Behavioral correlates of infrequent two-point MMPI code types at a university mental health center. Presented interpretive correlates for 95 college students who were seeking mental health services and who generated the following infrequently occurring MMPI code types: Spike 2, 2-0/0-2, 2-4/4-2, 2-6/6-2, 3-4/4-3, 3-9/9-3, 4-7/7-4, 6-7/7-6, 7-9/9-7, and Spike O. Descriptors were derived from intake interview and mental status information collected without knowledge of the MMPI profile. Those items that discriminated between each profile type and the remainder of the student mental health population (Chi Square, alpha = .05, .01) are presented as tentative interpretive descriptors that may be helpful in generating hypotheses for use with college student psychiatric outpatients.


Complex factorial structure of Ellis' Irrational Beliefs. Previous research with a newly developed children's scale for measuring Ellis' constructs with regard to irrational beliefs showed that while the scale clearly reflected theoretically predicted developmental trends, the internal consistency reliability of the overall 11-item scale was relatively low (.56). This low internal consistency suggested that the 11 items were in fact heterogeneous and were not measuring a single, univocal, construct. An exploratory factor analysis was performed on the responses of 788 fifth-through thirteenth-grade students. Results of the Alpha factor and analysis clearly indicate that the scale is multifaceted, i.e., comprised of four orthogonal, interpretable factors. Estimates of internal consistency reliabilities for the separate factors, when corrected for length, revealed that each of the new factors was more reliable than the full scale score in this sample. Potential revisions of the scale, as well as cautions for its use in clinical applications on its present form are discussed.


Lewinsohn's behavioral measures of social skill: their stability and relationship to mood level and depression among college students. Reports on investigations of the stability of eight of Lewinsohn's (1975) measures of social skill and their relationship to indices of depression and mood level in college students who are attending small informal discussion groups. Five of his measures showed no significant degree of stability across group sessions. The remaining measures, mainly indices of activity level, showed a significant though only moderate degree of generalizability. No significant differences in activity level were found between depressed and nondepressed Ss. However, several post-hoc analyses revealed that the variability of the Ss' mood and behavior across group sessions was associated significantly with their D30 scores. Depressed Ss were more variable in their mood and behavior. Implications of these results are discussed briefly.


Normative and validity data for the Missouri Children's Behavior Checklist. Presented normative data, collected on an unselected sample of 302 7- and 9-year-old children, for the Missouri Children's Behavior Checklist. Boys were found to be rated as more deviant than girls, while age, occupation of head of household, and estimated IQ were found to be unrelated to checklist ratings of deviant behavior. The use of a cutting point on the Total Pathology Scale of the checklist derived from the normative data identified a group of clinic children, 89% of whom were found to be in need of professional attention. The potential usefulness of the checklist as an aid in making important clinical decisions is discussed, as is the need for more extensive normative data.


Three patterns of brain damage of the WAIS. Compared four groups of matched Ss (40 each) in order to examine different subtest patterns of brain damage on the WAIS, using F-tests and age mean profiles. The groups were: Normals, diffuse cortical degeneration, right and left hemisphere damage. The results indicated three patterns: (1) a normal pattern; (2) a diffuse degenerative and right hemisphere pattern; and (3) a left hemisphere pattern. The diffuse degenerative results were not significantly different from the right hemisphere results. The left hemisphere pattern had no large verbal vs. performance differences. These patterns appear to be produced by the interaction of three brain damage effects: (1) a general effect; (2) a right hemisphere effect; and (3) a left hemisphere effect. Verbal tests are both "hold" and left hemisphere tests, while three Performance Tests are "don't hold" and right hemisphere tests. The WAIS requires other specific tests of brain damage for an adequate assessment of brain damage.


Visual-motor test performance: race and achievement variables. Tested rural Michigan black (N = 60) and white (N = 60) children of variant academic achievement on the Minnesota Percepto-Diagnostic Test for visual-motor skill development. The test, which consists of six gestalt designs for the person to copy, includes four measures of such skill development: Degree of copied design rotation and errors of separation of circle-diamond, distortion of circle-diamond and distortion of dots. In general, analyses that statistically controlled for intellectual level indicated that race was not a significant variable in the relationship of achievement level and visual-motor test performance. That is, such analyses resulted only in a significant achievement effect; low achievers, in comparison with high achievers, performed poorly on the copying test. Only with distortion of circle-diamond errors was a race interactive effect noted; i.e., black low achievers had significantly more errors than black high achievers, white low achievers or white high achievers. Results were discussed in relation to environmental determinants and symptomatology correlates.


The modified WAIS: an alternative to short forms. The Modified WAIS is an approach for shortening the total administration time of the WAIS by approximately 25%. The Modified WAIS uses the Information subtest as a criterion for raising the point at which initial questioning begins on 5 of the 11 subscales. The Modified WAIS was shown to correlate quite highly with the Standard WAIS: .999 for Verbal, Performance, and Full Scale IQ (N = 200). While the number of cases for which the Modified WAIS is applicable will vary from setting to setting depending on the number of cases that meet the criterion, the Modified WAIS appears to be a viable alternative to short forms.


Rekitting the Wechsler Paired-Associate Task: the Waterford Index. The Waterford Index provides a new scoring system for the Wechsler paired-associate task. Item performances across successive trials were coded so as to reflect the psychological phenomena of learning, forgetting and item effects (N = 50). The Index describes two rules for differentiating between cases of cognitive impairment and non-impairment. Rule 1 contrasts the respective contributions of learning and forgetting. Rule 2 takes account of cases characterized by a high proportion of correct responses. Against a criterion index based on performances on other psychological tests of organic dysfunction, the Waterford Index yielded higher predictive efficiencies than associated with other Wechsler indices, intelligence, and age.


Therapist-patient agreement and outcome in group therapy. Examined the importance of therapist-client agreement for therapy outcome in group therapy. Fifty-five clients comprised 12 groups conducted by 6 therapists. The study considered data in two phases. In the first an attempt was made to reduce clients' ambiguity about relationship aspects of therapy via a preparation for therapy. The success of this preparation was measured by comparing experimental and control groups on the degree of agreement between therapist and patient about the quality of the relationship they conjointly experienced. The preparation did not improve agreement. The second phase hypothesis was that there would be a significant relationship between agreement and therapy outcome. While there were scattered significant correlations between agreement and outcome, they were not correlated consistently with the same outcome scores, nor were they consistently positive or negative correlations. This inconsistent relationship was due partially to artifacts of person perception scores. An ancillary finding was significant change after therapy intervention. Agreement was not a powerful predictor of outcome in this study.


Influence of modelling and feedback provided by the supervisors in a microskills training program for beginning counsellors. Investigated the influence of modelling and feedback on the effectiveness of a microskills training program for beginning counsellors. The microskills taught were: attending behavior, minimal encourages to talk, open questions, and reflection of feeling and content. Twenty-four trainee counsellors were allocated to three treatment groups: (1) no modelling, no feedback (NMF); (2) modelling and feedback from the supervisor (MF); and (3) feedback from the supervisor (F). Analysis of variance showed that MF was superior to NMF and F in increasing use of the skill reflection of feeling. These results lead to the conclusion that the microskills taught differ in level of difficulty, and, hence, in the amount of information, through instructions, practice, modelling or feedback, that will bring these skills to ceiling level. Supervisor modelling and feedback appear to improve learning of the comparatively difficult skill, reflection of feeling.


A comparison of MMPI two-point codes in four alcoholism treatment facilities. Compared the frequency of two-point MMPI codes in four different alcoholism treatment facilities. Even though some differences were noted in terms of the different code types, the comparisons were more indicative of the similarity between treatment facilities. The 2-4/4-2 code type occurred most frequently in all of the treatment settings, yet it accounted for only 12--21% of the profiles in any facility. The implication of these findings for describing the "alcoholic" personality and for individualized treatment planning was discussed.


Beliefs about the causes of alcohol-related problems among alcoholic and nonalcoholic women. Both problem drinker and non-problem drinker college students and adult women assigned major responsibility for problem drinking internally to the problem drinker (N = 479). A distressing event and present or past environment received the next highest responsibility ratings in all groups. Actor-observer differences predicted by Jones and Nisbett (1971) did not occur. However, persons were likely to rate several causes as responsible for drinking problems. Female college students were more likely to perceive drinking problems as due to external factors and less likely to believe them due to heredity than were older women.


Sex offenders: three personality types.

Sex offenders: three personality types. Analyzed by a Q-type factor analysis MMPI profiles of 92 sex offenders institutionalized for psychiatric evaluation, which yielded three basic MMPI profile types. Altogether 88 of the 92 Ss coult be categorized into one of three types characterized by profile peaks on F,Sc; Pd,MA; or D,PD. Analysis of background information, social history items, nature of present crime, primary diagnosis, and ward observations revealed significant differences among the types. Of particular interest was the finding that the primary diagnosis for 85% of the "F,Sc" MMPI type was "no mental disorder" in spite of the fact that this group showed significantly more disturbed behavior on the ward (anxiety, depression, suspicion, and manic excitement) and had uniquely degraded their victims. The fact that two-thirds of these persons who had F scores greater than or equal to 80 and 50% denied the crime may have inadvertently affected diagnostic decisions.


Assessment of assertiveness in drug abusers. Administered measures of assertion, social assertion, aggression, and social anxiety to a heroin-addicted population, psychotic outpatients, court-referred drug users and a college student group (N = 114). The addicts and court-referred drug patients were less assertive, less socially assertive, and more socially anxious than non-addict populations. Furthermore, the heroin and psychiatric outpatient groups had a very high correlation between their assertion and aggression scores, which was not found in the college student or court-referred, drug-using group.


Sex of client as a factor in preference for an approach to counseling. In a reversed order, 90 Ss, from a general psychology course, in two groups of equal size, viewed two audiovisual tapes of a simulated first counseling session. The same counselor, same client, and same presenting concern of a vocational-educational nature were portrayed as representative of a client-centered and a behavioral approach to counseling. The Ss were asked to identify which film they preferred and why. A chi square analysis showed no difference between males and females. However, there was a statistically significant preference for the behavioral approach by both males and females. The major factor in the preference appeared to be the "structure" of the behavioral approach.


Attraction to therapy and therapist credibility as a function of therapy orientation. Exposed male and female Ss (N = 96) to psychoanalytic, behavioral, client-centered, or gestalt therapy, in the form of a brief written description and a 5-minute videotaped simulation. Attraction to therapy and various dimensions of therapist credibility were measured. The psychoanalytic presentation generated the greatest attraction and the greatest perceived total credibility. The gestalt presentation was next highest on these variables, followed by the behavioral and client-centered presentation. No significant effects for sex of S or sex by therapy approach interaction were reported. Explanations for and implications of these findings are discussed.


Employment of master's-level psychologists. Compared results from a survey of employment of Master's-level psychologists in the states of Michigan, Indiana, Ohio, and Kentucky to two previous studies recently published. It was found that results in all three studies are comparable; 87.6% of those mental health centers, state hospitals and other mental health organizations surveyed reported that they employ Master's-level psychologists. Duties of subdoctoral psychologists include testing, therapy, and community consultation. The finding that future Master's-level psychologists may find greater employment potential in towns with a population of less than 50,000 justifies future research in the area of Master's-level employment to consider demographic variables.


The influence of dosage form on papaverine bioavailability. The bioavailability of sustained-release papaverine HCl dosage forms were compared to equivalent doses of the drug administered as an elixir and conventional compressed tablets to 12 healthy human subjects. Papaverine plasma levels were determined using a gas-chromatographic procedure. The drug was absorbed more rapidly and completely from the two nonsustained-release formulations. There was a large intersubject variability, and the plasma half-life of the drug was esstimated to be 1 hour. The area under the plasma level-time curve for the nine sustained-release products ranged from 18 to 64% relative to the area achieved by the papaverine elixir. It was concluded that the sustained-release dosage forms of papaverine included in each study group could be considered bioequivalent, but they exhibited inadequate bioavailability relative to either the elixir or the compressed tablet dosage form.


Clinical pharmacology of sodium cellulose phosphate. The safety and effectiveness of sodium cellulose phosphate (SCP) in the treatment of calcium urolithiasis of absorptive hypercalciuria was explored. Eighteen patients with absorptive hypercalciuria with intestinal hyperabsorption of calcium, normal or suppressed parathyroid function, and active stone disease received 10 to 15 Gm SCP daily (2.5 to 5 Gm with meals) and 2 to 3 Gm magnesium gluconate daily (1 to 1.5 Gm twice daily orally separately from SCP) for eight to 54 months, while maintained on a moderate calcium and oxalate restriction. During treatment, serum calcium, immunoreactive parathyroid hormone, and urinary cyclic AMP remained within the normal range. Serum alkaline phosphatase and bone density (measured by photon absorptiometry) did not change significantly or remained within normal limits. Serum concentrations of magnesium, copper, zinc, and iron and blood hematocrit were not significantly altered by therapy. However, urinary calcium returned toward normal, and incidence of renal stone formation markedly decreased. The results suggest that SCP is a safe and an effective drug for absorptive hypercalciuria.


Anxious symptomatic volunteers in the Twin Cities: sociodemographic description and MMPI psychodiagnosis. This paper underscores the need for true sample selection before statistical inference of any value can be made. Its findings suggest that the sample selection strategy of symptomatic volunteers can produce samples of anxious subjects with remarkable demographic similarity across the country. Anxiety as a constitutional rather than pathognomonic symptom is illustrated by the heterogeneity of its psychometric evaluation in our volunteers. Expecting a drug to safely relieve the anxiety of all anxious symptomatic volunteers is akin to expecting a drug to safely relieve the headaches of all headache sufferers. We feel that careful psychodiagnosis remains the best sample selection strategy.


Bethanidine elimination from plasma.

Bethanidine elimination from plasma. Bethanidine was administered intravenously to six hypertensive patients with normal renal function and five hypertensive patients with renal impairment. After administration of 0.7 mumole/kg, blood was sampled at frequent intervals for measurement of plasma bethanidine. The plasma levels were analyzed on a three-compartment exponential open-model system. The second rapid elimination phase (beta) had a half-time of 3.4 hours in normal subjects and was insignificantly prolonged to 16.4 hours in renal impairment. There was an extended terminal elimination phase of 90 and 70 hours for normals and impaired, respectfully. The volume of distribution at pseudoequilibrium was 2.8 and 1.6 liters/kg, respectively, suggesting significant sequestration of the drug in body tissues. The pharmacokinetic constants of bethanidine in normal and impaired renal functions were similar.


An analgesic comparison study of indoprofen versus aspirin and placebo in surgical pain. Single oral doses of 100 and 200 mg indoprofen were compared with 600 mg aspirin and placebo in a double-blind, completely randomized study of hospitalized patients with postoperative, post-fracture, or musculoskeletal pain. The patients evaluated their pain for 5 hours after administration of the study drug. Each of the three active treatments performed significantly better than placebo. The 200-mg dose level of indoprofen demonstrated the greatest analgesic activity based on pain intensity and pain relief scores and on the patients' global evaluations. The analgesic activity of 100 mg indoprofen fell between that of 200 mg indoprofen and 600 mg aspirin and was not significantly different from either.


Blunting of exercise-induced tachycardia and renin release 24 hours after a single dose of sotalol. Sotalol significantly reduces resting and exercise-stimulated heart rate and plasma renin activity 2 hours and to a lesser degree also 24 hours after oral administration of a single 200-mg dose in healthy volunteers. Because of this 24-hour beta-adrenoceptor blocking effect, sotalol should be suitable for once-daily dosing in clinical practice.


Studies on the pharmacokinetics and pharmacodynamics of the beta-adrenergic blocking agent sotalol in normal man. After intravenous injection, sotalol follows a two-compartment distribution pattern. The processes of distribution and elimination are of first order; the intravenous biological half-life is 6 to 8 hours. The drug is mainly excreted by glomerular filtration via the kidney, and metabolites are not found. Of the pharmacodynamic parameters measured, the isoproterenol-induced changes in heart rate, diastolic blood pressure, and free fatty acid return to baseline values immediately during the injection of the beta blocker. Peripheral arterial circulation, lactate, glucose, and pyruvate respond to the beta blocker after a delay. Besides the compartmental distribution of sotalol, other mechanisms of sotalol such as varying responses of the receptors to sotalol or more sluggish intrinsic kinetics of the decrease of parameters measured have to be considered. The effects of various beta blockers may be qualitatively and quantitatively differentiated on the basis of experiments with our test model using steady-state isoproterenol infusion in humans.


Thrice-daily blood pressure readings on sotalol in the treatment of hypertension: once- versus twice-daily regimen. Thirty patients with mild to severe essential hypertension satisfactorily controlled by twice-daily sotalol therapy entered a double-blind, crossover study comparing the efficacy, tolerability, and safety of their usual twice-daily sotalol administration with the same dosage given once daily. Each double-blind period extended eight weeks, during which blood pressure and pulse rate were recorded by a nurse three times daily on alternate days during the last week of each period in the patients' usual living conditions. Plasma sotalol concentration was measured before the morning dosage of sotalol. No statistically significant differences in the parameters were found between once- and twice-daily sotalol administration using sotalol in daily dosages from 80 to 320 mg. All patients concluded the trial, and no increase in side effects was noted during the once-daily period.


Pharmacologic considerations in determining efficacy of once-daily sotalol administration to hypertensive patients. The beta-adrenergic blocker sotalol, administered only once a day, proved an extremely effective and safe agent for the 24-hour control of essential hypertension, even in patients with a severe form of the disease. Significant (P less than 0.01) decreases from the baseline levels were noted in both supine and standing blood pressures as early as the first week after sotalol administration in the 15 patients who participated in the open study. All patients were titrated and controlled by six to eight weeks or sooner. By the conclusion of the 12-week study, mean supine systolic blood pressure in the 15 patients fell 21 per cent (from 176 mm Hg to 139 mm Hg), and mean supine diastolic blood pressure was down 23 per cent (from 115 mm Hg to 89 mm Hg). Standing values were similarly decreased by sotalol administration at a mean daily dose of 341 mg. Two of the patients also received concomitant 25 mg hydrochlorothiazide per day, and four received 40 mg furosemide per day. A comparison with the pretherapy placebo values indicates that all the declines were highly significant (P less than 0.001). Sotalol was very well tolerated, an no adverse reactions were reported during the entire study. There were also no significant changes in laboratory findings except for a drop in serum cholesterol.


Golgi and EM studies of the formation of dendritic and axonal arbors: the interneurons of the substantia gelatinosa of Rolando in newborn kittens. Golgi studies in newborn kittens show that the two most prevalent interneurons in Rexed's lamina II of the dorsal horn of the medulla, the stalked cell and islet cell (Gobel, '75a,b, '78b) form their dendritic arbors in a similar fashion. At birth, both cell types are present in forms ranging from immature, in which numerous short dendrites radiate from the cell body in all directions, to relatively mature in which their dendritic arbors have elongated in specific directions and the adult branching pattern is already evident. During postnatal maturation, many dendrites are lost while only a few go on to lengthen. The unmyelinated axons of both cells are first recognized in forms in which lengthening dendrites have taken on their preferred direction of orientation. The two parts of Rexed's lamina II, i.e., layers IIa and IIb have already reached their adult mediolateral width at birth and the neuropil has nearly achieved its adult compactness. Space in the compact neuropil for elongating neuronal and astrocytic processes becomes available through the disintegration of many existing dendrites and by an overall fourfold increase in the rostrocaudal length of the dorsal horn of the medulla during postnatal maturation. At birth, the lengthening of the plasma membranes of elongating neuronal and astrocytic processes proceeds as vesicles (addition vesicles) found in aggregates throughout dendrites, unmyelinated axons and astrocytic processes fuse with and become incorporated into the existing plasma membranes. In addition, many dendrites in layers IIa and IIb are beading up and disintegrating. Within the beads, neurotubules are lost and addition vesicles fuse with each other to form small cavities. These cavities continue to enlarge, hollowing out the beads. The cavities ultimately open to the intercellular space as their membranes fuse with the plasma membrane of the beads. Finally, the beads disintegrate and their plasma membranes fragment. The thread-like segments between adjacent disintegrating beads shrivel until they ultimately disappear. Disintegration of beaded dendrites results in very little debris and does not provoke a phagocytic glial reaction. The disintegration of a dendritic branch takes place in spite of synaptic input from non-primary axons and is thought to occur from a failure to establish synaptic connections with primary axonal endings.


Afferent projections to the ventral tegmental area of Tsai and interfascicular nucleus: a horseradish peroxidase study in the rat. Using the retrograde transport of horseradish peroxidase (HRP), a study has been made of projections to the ventral tegmental area of Tsai (VTA) and related dopaminergic cell groups (A 10). In order to minimise the possibility of damage to fibres of passage, a technique was evolved for the microiontophoresis of HRP such that minimal current strengths and durations were applied. In addition to a sham injection, control injections were also made to the medial lemnisuc, red nucleus, deep tegmental decussations, mesencephalic reticular formation and brachium conjunctivum. Following HRP injections confined to the areas of the VTA containing the dopamine cell groups, labelled neurons appeared in prefrontal cortex, dorsal bank of rhinal sulcus, nucleus accumbens, bed nucleus of stria terminalis, amygdala, diagonal band of Broca, substantis innominata, magnocellular preoptic area, medial and lateral preoptic areas, anterior, lateral and postero-dorsal hypothalamus, lateral habenular, nucleus parafascicular nucleus of thalamus, superior colliculus, nucleus raphe dorsalis, nucleus raphe nagnus and pontis, dorsal and ventral parabrachial nuclei, locus coeruleus and deep cerebellar nuclei. Regions containing catecholamine groups A 1, A 5, A 6, A 7, A 9, A 13 and the serotonin group B 7 corresponded to the topography of labeled cell groups. Injections of HRP to the interfascicular nucleus resulted in labeling predominantly confined to the medial habenular and median raphe nuclei. The results are discussed in relation to the known connections of these regions. Other regions of the brain labelled by VTA injections are assessed in relation to control injections and the limitations of the HRP technique. A review of the organisation of some of these afferents in relation to the known cortical-subcortical-mesencephalic projection systems, suggests that the VTA is in a position to recieve information from a massively convergent system derived ultimately from the entire archi-, paleo-, and neo-cerebral cortices. In addition A 10 dopaminergic neurons are known to project to restricted regions of both pre-frontal and entorhinal cortices, which themselves also recieve massively convergent association cortico-cortical connections. It would appear reasonable to propose that these neurons perform a correspondingly important integrative function.


Terminal proliferation in the partially deafferented dentate gyrus: time courses for the appearance and removal of degeneration and the replacement of lost terminals. The time courses for the appearance and removal of degenerating terminals and the loss and reappearance of intact terminals were investigated in the partially denervated inner molecular layer of the dentate gyrus of the adult rat. Dense degeneration was evident in the neuropil within 26 hours following contralateral hippocampectomy. These profiles increased rapidly in number until the maximal degree was reached at two to three days postlesion, after which the degenerating terminals were quickly removed from the neuropil. A more rapid rate of removal occurred during the 3-to 5-day survival period than from 6 to 50 days postlesion. The intact terminal population dropped 35% within two days of the lesion and remained at this level until six to eight days postlesion when the number began to steadily increase. The time course for this reappearance can be divided into two phases: a period of rapid terminal addition from 6 to 15 days followed by a phase of slower acquisition. This recovery continued until the normal synaptic density was regained by 50 to 65 days postlesion. These results indicate that a substantial proportion of degenerating endings are removed well in advance of the time at which terminal proliferation begins, suggesting that certain changes other than merely the removal of competitive inputs must take place prior to growth of new terminals. Possible explanation suggested by the present results for the delay in the onset of sprouting include: (1) an absence of appropriate postsynaptic targets during the 2-to 5-day postlesion period and (2) inhibition of axonal growth by the glial cells which are phagocytizing the degenerating products. Beyond the sixth postlesion day the rate at which new terminals appear does correlate with the rate at which degeneration is removed. This suggests that once underway the time course for sprouting may be determined by the avaiabliity of postsynaptic sites.


Determinants of cell shape and orientation: a comparative Golgi analysis of cell-axon interrelationships in the developing neocortex of normal and reeler mice. Patterns of dendritic development in the neocortex of normal and reeler E15-17 mouse embryos are studied in Golgi impregnations. Interactions between dendrites and axon-rich strata appear to be critical determinants of dendritic morphology in both genotypes. Firstly, axon-dendrite proximity appears to stimulate dendritic sprouting, elongation and branching. Secondly, the position of the axon-rich strata with respect to the differentiating cell appears to determine the direction of dendritic growth and thereby the ultimate configuration of the dendritic arbor. With regard to specific cell configurations, a multipolar form is generated when the cell is embedded in an axon-rich zone. A monopolar or bipolar configuration is achieved when the cell lies in the axon-poor cortical plate and addresses and axon-rich stratum with one or both radially extended migratory processes. Such variations in the configuration of neurons with polar dendritic systems may be observed uniquely in the mutant cortex because axon-rich zones are stratified anomalously at multiple levels in the cortical plate. As a consequence, polar dendritic systems develop from either the superior, the inferior or both somatic poles of postmigratory cells. Pyramidal cells may, therefore, develop a normal upright or an abnormal "upside-down" disposition. Regardless of the orientation of the polar dendritic system, the axon emerges from the inferior aspect of the cell suggesting that there has been no rotation of the original migratory axis of the cell.


The cytoarchitecture of the interfascicular nucleus and ventral tegmental area of Tsai in the rat. The cytoarchitecture of the ventral tegmental area of Tsai (VTA) has been studied in detail in the rat with the acid of both conventional techniques and glyoxylic acid-fluorescence histochemistry. Three main dopamine containing cells groups can be distinguished: nucleus paranigralis, nucleus parabrachialis pigmentosus, nucleus linearis raphe caudalis. Nucleus parabrachialis pigmentosus lies dorsally, and nucleus paranigaralis ventrally in the VTA, while nucleus linearis continues posteriorly and medially from VTA and extends dorsally in the midline up towards the dorsal raphe nucleus. Fluorescent neurons in these three groups correspond to the A10 group. In addition to these previously described findings, the present study shows evidence for further small but cytoarchitecturally distinct dopaminergic group called the interfascicular necleus. This lies anteriorly and ventrally in the ventral tegmentum in the midline, dorsal to the rostral portion of the interpeduncular nucleus and interpeduncular fossa. The significance of these cytoarchitectural findings is discussed in relation to the known connections of the region.


A Golgi study of the ventral tegmental area of Tsai and interfascicular nucleus in the rat. The ventral tegmental area of Tsai (VTA) and interfascicular nucleus of the adult rat brain has been studied with two variants of the Golgi method in three planes of section. Neurons were studied in relation to the cytoarchitectural groupings of the VTA. Dendritic organisation and dendritic fields were mapped out for each cytoarchitectural subgroup and cell types within each subgroup were classified on the basis of cell size and dendritic morphology. In each subnucleus of VTA, neurons had distinct characteristics. In nucleus paranigralis neurons were small to medium in size and their dendritic fields organised in an approximately horizontal plane orientated in an anteromedial direction and slanting dorsally over the interpeduncular nucleus and fossa. Neurons of the parabrachial group were small to medium sized with no preferential orientation. In nucleus linearis raphe caudalis small neurons were strongly orientated in the plane of the nucleus in a dorso-ventral direction slanting forwards. Neurons in the interfascicular group were small to very small and their maximum dendritic extents were seen in the horizontal plane. In frontal section they formed a compact ball of cells in the midline and were separated on either side from the larger neurons in the medial edge of nucleus paranigralis. In general VTA neurons tended to fall into one of two morphological categories. Type 1 were small to medium, and had two to four primary dendrites which divided into varicose secondary dendrites. Type 2 were medium sized, with two to five primary dendrites. Both primary and secondary dendrites and the cell soma of Type 2 neurons were moderately spiny. Secondary dendrites were not varicose. Forms also occurred which were intermediate between Types 1 and 2. In the nucleus paranigralis, Type 1 was more common medially, while Type 2 was more common laterally, particularly in the ventrolateral paranigral region. Only neurons of Type 1 were seen in nucleus linearis raphe and interfascicular nuclei. Local axon circuits were observed to arise from the primary dendrites of Type 1 neurons and to ramify close to neighbouring neurons. Axon swellings from such circuits were observed to make apparent contact with primary dendrites of nearby neurons and clusters of axon swellings were observed near cell somas of neighbouring impregnated neurons of similar type. The results are discussed and particular attention is paid to the similarities and differences between VTA and the substantia nigra pars compacts (SNC). The major difference appears to be that, whereas in SNC dendrites are organised in vertical as well as horizontal planes, in the VTA no long ventrally directed dendrites were observed. Combining these results with known cytoarchitecture and connections of VTA and SNC, it appears that fundamental differences occur between VTA and some neurons of the SNC, both in the nature of their morphology and intrinsic organisation, and in the organisation of their efferent and afferent connections.


The decussation of the retinothalamic pathway in the cat, with a note on the major meridians of the cat's eye. We have studied the naso-temporal division of the retinothalamic pathway of the cat by making large unilateral injections of horseradish peroxidase into the lateral geniculate nucleus. In confirmation of previous work, our retinal whole-mounts show a distinct vertical decussation line separating the contralaterally projecting nasal retina from the ipsilaterally projecting temporal retina. The ipsilateral decussation line is quite sharp, while the contralateral decussation is somewhat more diffuse, with numbers of large cells extending a few degrees into the temporal retina. However, in contrast to the results of optic tract section, our material (demonstrating the thalamic component only) does not reveal any significant population of contralaterally projecting small cells across most of the temporal retina. The previous observation of approximately 200 micrometer of naso-temporal overlap in the area centralis is confirmed here, and evidence is presented that this overlap may increase at eccentricities above the horizontal meridian. Taken together with previously published data, this demonstration of the vertical decussation line has allowed us to estimate the relative inclinations of the major meridians of the cat's eye.


The retinothalamic pathways in Siamese cats. By injecting one lateral geniculate nucleus with large amounts of horseradish peroxidase (HRP), we have determined the retinal distributions of contra- and ipsilaterally projecting retinothalamic ganglion cells in the Siamese cat. In accord with the data of others, we observe that large numbers of temporal ganglion cells, which normally send axons ipsilaterally, instead misproject to the contralateral thalamus. However, in contrast to the expectations raised by previous work, we do not find the Siamese defect to be a simple 20 degrees shift of the naso-temporal decussation line. Rather, there is intermingling of the crossed and uncrossed retinothalamic populations in the temporal retina, with a gradual increase in the proportion of ipsilaterally projecting ganglion cells as one moves temporally. Thus, the Siamese abnormality represents not only a temporal displacement of the retinothalamic decussation line, but also a smearing of the normally rather sharp division between regions of ipsilateral and contralateral projection. Cell size measurements and anterograde transport of H3-proline confirm the HRP findings and suggest differential effects of the Siamese abnormality according to ganglion cell class. In particular, it appears that the large ganglion cells to misproject to a greater degree than the rest of the retinothalamic population.


A cerebello-pulvino-cortical and a retino-pulvino-cortical pathways in the cat as revealed by the use of the anterograde and retrograde transport of horseradish peroxidase. A cerebello-pulvino-cortical and a retino-pulvino-cortical pathways were revealed in the cat by means of the horseradish peroxidase (HRP) method. The sites of termination of the cerebellofugal and retinofugal fibers in the pulvinar nucleus (Pul) were visualized by the use of the anterograde transport of HRP. The cerebello-pulvinar fibers were found to arise mainly from the parvicellular region of the lateral cerebellar nucleus and to terminate contralaterally in a narrow area at the extreme dorsolateral edge of the Pul at the level of the stereotaxic frontal plane A-7.0. The area of terminal ramification of retino-pulvinar fibers was seen as a thin sheet lying at the extreme lateral edge of the Pul through most of the rostrocaudal extent of the Pul, bilaterally with contralateral predominance. The cerebellorecipient area in the Pul did not seem to overlap with the retinorecipient Pul area; the former appeared to be contiguous ventrolaterally to the latter. The cerebellorecipient and retinorecipient Pul areas were also observed to be connected reciprocally with the cerebral cortical areas; the former was connected with the most posterior part of the area 20, and the latter with the area 19.


Development of synaptic arrays in the inner plexiform layer of neonatal mouse retina. Retinas from mice of the C57BL/6 strain were sampled at frequent intervals from birth to postnatal day 33 to determine the numerical density of conventional and ribbon synapses within the inner plexiform layer (IPL) as a function of time. Synaptic arrays of the IPL were formed in three phases. During Phase I, from day 3 to day 10, conventional synapses were produced at a mean rate of 0.44 synapses/1,000 micrometer3/hour, but no ribbons were seen. During Phase II, from day 11 to day 15, ribbons formed at a rate of 0.38 ribbons/1,000 micrometer3/hour and conventional synapses were produced at a rate of 1.15 synapses/1,000 micrometer3/hour. Phase III began at day 15, the approximate time of eye opening in these animals, and was characterized by a sharp reduction in the rate of production of both ribbons and conventional synapses. During this phase ribbons achieved a final mean density of 113 ribbons/1,000 micrometer3 and conventionals achieved a final mean density of 250 synapses/1,000 micrometer3. Serial appeared in Phase II but remained at low densities.


Spinal projections from the mesencephalic and pontine reticular formation in the North American Opossum: a study using axonal transport techniques. The results from several experimental approaches lead to the following conclusions. The nucleus cuneiformis projects to at least lumbar levels of the spinal cord. Its axons course through the ipsilateral sulcomarginal and ventral funiculi to distribute within lamina VIII and adjacent portions of lamina VII. Neurons within the nucleus reticularis pontis (RP), particularly within more medial parts of the nucleus, project through comparable routes to the same laminae. In addition, however, neurons within the lateral and dorsolateral RP relay through the lateral and dorsolateral funiculi, ipsilaterally, and the dorsolateral funiculus, contralaterally. Axons could be traced from the dorsolateral tracts to laminae IV through VII, lamina X and, in some instances, to laminae I and II. Injections of the dorsolateral pons also label the intermediolateral cell column and an area presumed to be the sacral parasympathetic nucleus. Many of the neurons which contribute to the contralateral bundle are located adjacent to the ventral nucleus of the lateral lemniscus. The nucleus reticularis gigantocellularis projects mainly via the sulcomarginal, ventral and lateral funiculi to laminae VIII and adjacent portions of lamina VII. The nucleus reticularis gigantocellularis pars ventralis innervates the same laminae; but, in addition, projects heavily to laminae I and II, to lateral portions of laminae IV through VII; to laminae IX and X and to the intermediolateral cell column. Axons destined for laminae I and II, as well as IV through VII and X, traverse the dorsolateral funiculi as described for the cat by Basbaum et al. ('78). Neurons within the nucleus reticularis parvocellularis project to cervical levels, mainly through the ventral funiculi. In general our results show that reticulospinal projections are more complex than suggested by degeneration methods and that laminae I, II. lateral parts of laminae IV-VII, laminae IX and X, as well as the intermediolateral cell column and sacral parasympathetic nucleus are targets of axons from specific areas.


Afferent connections to the amygdaloid complex of the rat and cat. I. Projections from the thalamus. By the use of the retrograde transport of horseradish peroxidase (HRP), the projections from the thalamus to the amygdala were investigated in the rat and cat, with main emphasis on the former species. HRP was injected stereotactically by microiontophoresis in the various amygdaloid nuclei. Several control procedures including the use of different approaches for the introduction of the micropipette were undertaken to eliminate the possibility of misinterpretation due to uptake of the protein by adjacent structures or fibers en passant. The paraventricular and paratenial nuclei of the thalamus were found to project throughout the entire amygdaloid complex. The medial geniculate complex and the basal nucleus of the ventromedial complex (the thalamic taste relay) mainly project to the centromedial part of the amygdala. The basolateral nucleus is the main recipient of a hitherto undescribed bilateral thalamo-amygdaloid pathway originating in the interanteromedial nucleus. The parafasciculare nucleus projects to the central nucleus of the amygdala; in the cat mainly to the lateral subdivision of the central nucleus. The findings are discussed in relation to previous anatomical and electrophysiological studies centered on the amygdaloid complex. Special reference is made to the possible role of the thalamo-amygdaloid connections in the conveyance of sensory information to the amygdala.


Cell death of motoneurons in the chick embryo spinal cord. IV. Evidence that a functional neuromuscular interaction is involved in the regulation of naturally occurring cell death and the stabilization of synapses. Embryos immobilized with neuromuscular blocking agents for differing periods between 4.5 and 9 days of incubation had an increased number of motoneurons in the brachial and lumbar lateral motor columns. Treatment with alpha-cobratoxin (alpha-CTX) on days 4--9, for instance, was able to prevent virtually all natural cell death during this period; control embryos had an average of 22,500 lumbar motoneurons on day 5.5, and 13,500 on day 10, whereas treated embryos had approximately 21,000 cells on day 10. Curare, alpha-CTX, alpha-bungarotoxin (alpha-BTX) and botulinum toxin were all about equally effective in preventing cell death. Similar treatment begun after day 12, however, had no effect on cell number. If even a partial immobilization was continued after day 10 (in embryos totally immobilized earlier) most of the excess neurons were maintained, in some cases right up to hatching, at which time the embryos died due to respiratory failure. In contrast, when administration of the immobilizing agents was stopped, allowing the embryos' motility to return to control levels, the excess neurons underwent a delayed cell death and total cell number fell to below control levels by days 16--18. Limb muscles from embryos with excess motoneurons exhibited relatively normal differentiation and had acetylcholinesterase (AChE) stained endplates which were innervated. Following curare treatment the two wing muscles, anterior and posterior latissimus dorsi, were found to have an increased number of AChE-stained endplates, whereas the only leg muscle examined quantitatively--the ischioflexorius (IFL)--did not; the IFL, did, however, have a markedly reduced variance in endplate distance, as well as other apparent differences suggesting an altered pattern of innervation. Our findings imply that the number of motoneurons undergoing natural cell death is closely related to muscle activity. Thus, functional interactions at the developing neuromuscular junction seem to be critical in controlling cell death. If a retrograde trophic factor is involved its action is somehow related to muscle activity.


Quantitative electron microscopic evidence for reinnervation in the adult rat interpeduncular nucleus after lesions of the fasciculus retroflexus. The method of electron dense degeneration has been used to make a quantitative study of the projection from the habenula through the fasciculus retroflexus (FR) to the interpeduncular nucleus (IPN) in the rat. The IPN si a midline structure onto which the right and left fasciculi converge. In the rostral part of the IPN the fascicular axons from each side form synapses throughout the mediolateral extent of the ventral two-thirs of the nucleus. In the caudal part of the IPN the fascicular axons from each side terminate to an equal extent in two discrete, parasagittal zones, situated one on side in the mid-mediolateral extent of the IPN. These zones contain clusters of neurons located along the course of a characteristic row of arterioles and venules penetrating the IPN from its ventral surface. In both rostral and caudal parts of the IPN the fascicular axons form single synaptic contaerpeduncular neurons, but caudally, in the two parasagittal zones they also form crest synapses. Crest synapses are only found in this part of the IPN. In crest synapses two presynaptic terminals form markedly asymmetrical contacts with the parallel opposing sides of an attenuated dendritic appendage (the crest).  After unilateral fascicular lesions only one member of a pair of axon terminals contacting a crest degenerates. After bilateral fascicular lesions, however, there are many instances in which both members of a crest pair degenerate. This indicates that the axon terminals from the right and left fasciculi are segregated at the level of the crests, in such a way that one terminal comes from the right fasciculus and one from the left. At longer survivals after unilateral or bilateral fasciculus lesions the degeneration is completely removed, but crest synapses are still present, indicating that the presence of fascicular axons is not necessary for the maintenan ce of crests in the IPN. To investigate the effects of chronic deafferentation, the left fasciculus was destroyed and, after a survival of at least six weeks (sufficient for all degeneration to be removed) the right fasciculus was destroyed one day before killing. Under these conditions there are many crests in which both axon terminals  show degeneration. The proportion of such doubly degenerating crest synapses is similar to that found after acute (1 day) bilateral lesions, indicating that axons from the right fasciculus have reinnervated sites formerly occupied by the left fasciculus. We conclude that during normal development there is some constraint which prevents both sides of a crest being innervated by axons from the fasciculus of the same side of the brain, but that this constraint is not effective after unilateral fascicular lesions in the adult.


Differentiation of photoreceptors and horizontal cells in the embryonic mouse retina: an electron microscopic, serial section analysis. The early differentiation of photoreceptors and horizontal cells in the mouse retina has been studied with serial thin sections and reconstructions in embryos on the fifteenth and seventeenth days of gestation (E15 and E17). The following developmental sequences have been inferred. At E15 photoreceptors develop from ventricular cells when a long vitreal process fails to develop following mitosis, and the end of the ventricular process forms a bulbous enlargement (the future inner segment) which contains a pair of centrioles and a cilium and extends into the optic ventricle. This future inner segment is considerably larger at E17, but otherwise the photoreceptors resemble those seen at E15. At E15 horizontal cells develop from ventricular cells when a long vitreal process fails to develop following mitosis, and the end of the ventricular process detaches from the junctional complex at the ventricular surface. By E17 future horizontal cells are located in the middle of the ventricular layer (neuroblastic layer) and have developed from bipolar shaped cells into cells with multiple branching processes, predominantly radially arranged but rarely with a more tangential orientation. These relatively advanced cells at E17 resemble closely the earliest stage of horizontal cell formation described previously in silver studies by Cajal. A scheme is proposed which explains the initial differentiation of several of the major cell types in the retina in terms of two key features: whether or not the call remains attached to the junctional complex and whether or not a vitreal process grows into the ganglion cell layer. By independent variations in these two features, four classes of cells are produced that, by virtue of their differing environments, differentiate into four cell types: ganglion (and amacrine) cells, horizontal cells, photoreceptors, and Müller cells.


The origin of descending pathways in the dorsolateral funiculus of the spinal cord of the cat and rat: further studies on the anatomy of pain modulation. There is considerable evidence that the dorsolateral funiculus (DLF) of the spinal cord contains descending pathways critical for both opiate and brainstem stimulation-produced analgesia. To obtain a comprehensive map of brainstem neurons projecting to the spinal cord via the DLF, large injections of horseradish peroxidase (HRP) were made into the lumbosacral spinal cord of cat and rat. These injections were made caudal to midthoracic lesions which spared only a single DLF or ventral quadrant (VQ); thus only those neurons whose axons descended in the spared funiculus would be labelled. Cells with descending axons in the VQ were concentrated in the medullary nucleus raphe pallidus and obscurus, nucleus retroambiguus and in various subregions of the reticular formation including the nucleus reticularis ventralis, gigantocellularis, magnocellularis, pontis caudalis and pontis oralis. Significant numbers of neurons were also found in medial and lateral vestibular nuclei and in several presumed catecholamine-containing neurons of the dorsolateral pons. In the rat, but not in the cat, considerable numbers of cells are present in the mesencephalic reticular formation just lateral to the periaqueductal gray. In both species, some cells were found in the paraventricular nucleus of the hypothalamus. Brainstem cells projecting in the DLF were concentrated in the nucleus raphe magnus and in the adjacent nucleus reticularis magnocellularis, ipsilateral to the spared funiculus. Significant numbers of cells were found in the dorsolateral pons, differing somewhat in their distribution from those projecting in the VQ. DLF-projecting cells were also present in the ipsilateral Edinger-Westphal nucleus and periaqueductal grey contralateral red nucleus of the midbrain and in the ipsilateral hypothalamus. Smaller projections from other sites are described. These results are discussed in terms of the differential contribution of several brainstem neuronal groups, including the serotonergic nucleus, raphe magnus, the ventromedial reticular formation of the medulla, and various catecholamine-containing neurons of the dorsolateral pontine tegmentum to the analgesia produced by opiates and electrical brain stimulation.


Interneuron circuits in the lateral geniculate nucleus of monocularly deprived cats. This work investigated the function of interneurons and other types of cells in the lateral geniculate nucleus (LGN) in cats raised to adulthood with one eye sutured closed. In order to understand the basis of the commonly found deficit of Y-type relay cells in the deprived layers of the LGN, we looked for reduced or defective activity in other cells which also receive an afferent projection from Y-type ganglion cells in the visually deprived retina. Monocular deprivation did not produce a deficit in the activity of a class of interneurons which receive direct optic inputs from the same ganglion cells in the deprived eye that also drive the Y-type relay cells. Likewise, the Y-type afferent input from the deprived eye to XY-type relay cells was normal. The XY-type cells have mixed or hybrid receptive field properties and both X and Y excitatory inputs; although the Y-inputs to these cells are often much weaker than the X-inputs. The normal properties of Y-type interneurons and XY-type relay cells in the deprived LGN suggest that neither a retinal dysfunction nor an inherent inability of the Y-type optic tract axons to form adequate synapses onto LGN neurons are factors which would readily account for the reduction of Y-type relay cells in monocularly deprived cats. The hypothesis that the deprived Y-type relay cells may have difficulty in forming synaptic connections onto postsynaptic, binocular neurons was supported by observations of responses of cells in the perigeniculate region. Normally, perigeniculate neurons receive a strong binocular input from Y-type relay cells as well as an X-input in at least some cases. In binocular perigeniculate cells of the sutured cats, no inputs from deprived Y-type relay cells could be identified although a longer latency input, typical of that from X-type relay cells, was present.


Postnatal neurogenesis in the kitten retina. Postnatal neurogenesis in the kitten retina was studied using 3H-thymidine radioautography. Kittens were injected with 3H-thymidine at 1 day, 10 days, 3 weeks or 4 weeks after birth and allowed to survive until 14 weeks of age. Labeled neuronal nuclei were not found in the ganglion cell layer in any of the retinas, but they were seen in the other nuclear layers of the same retinas. In retinas from kittens injected at one day after birth, the peripheral 80% of the length of the retina (in sections cut parallel to the dorsoventral meridian) contained labeled nuclei; the central 20%, around the optic disc, contained no labeled nuclei. Near the ora serrata most nuclei in both inner and outer nuclear layers were labeled. Away from the ora serrata the proportion of labeled to unlabeled nuclei gradually decreased. Labeled nuclei extended farther centrally in the the inner than the outer nuclear layer. The same pattern of labeling was repeated in retinas from kittens injected at ten days after birth, but fewer nuclei were labeled, and the central, unlabeled region around the optic disc was longer--55% of the length of the retina. Only a few nuclei near the ora serrata were labeled in retinas from kittens injected at three weeks after birth, and no labeled neurons were found in kittens injected at four weeks. From these results we conclude that all of the ganglion cells in the kitten retina are present by one day after birth, as are all of the other neurons in the central retina. In peripheral regions of the inner and outer nuclear layers, proliferation of cells destined to become neurons continues up to three weeks after birth.


The longitudinal zonal pattern in the paramedian lobule of the cat's cerebellum: an analysis based on a correlation of recent HRP data with results of studies with other methods. In a preceding study of the distribution of retrogradely labeled cells in the inferior olive of the cat after microinjections of horseradish peroxidase (HRP) in the contralateral paramedian lobule (Brodal and Walberg, '77b), three longitudinal zones were distinguished. The zones were assumed to correspond to Voogd's zones C1, C2 and D, receiving their afferents from parts of the dorsal accessory olive, of the medial accessory olive and of the dorsal lamella of the principal olive, respectively. Labeled cells were not found in the ventral lamella of the principal olive, however, although there is no doubt that also this projects to the paramedian lobule. In the present study, iontophoretic ejections, covering the extreme lateral part of the paramedian lobule, gave rise to labeling of cells in the ventral lamella. It is concluded that the zone D in the paramedian lobule can be subdivided into two, a lateral, D2, and a medial, D1, receiving fibers from the ventral and dorsal lamella, respectively. Neither zone extends throughout the entire length of the paramedian lobule. Both are lacking most rostrally and most caudally. This and other findings prompted a renewed analysis of the entire pattern of zonal representation in the paramedian lobule, based on correlations of our observations with the HRP method with data obtained with other methods. The results of this analysis are briefly described and summarized in a diagram (fig. 3B). It is particularly remarkable that zone B is present in some folia medially. A somatotopical arrangement appears to be present within all zones. A full account and documentation will be presented separately (Brodal and Kawamura, '80).


Topological analysis of the brain stem of the lungfish Lepidosiren paradoxa. The ventricular sulcal pattern and the cellular structure of the brain stem of the lungfish Lepidosiren paradoxa have been studied in transversely cut Nissl and Bodian stained sections. Five longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis and the sulcus medianus superior could be distinguished. In the isthmus region a number of obliquely oriented sulci is present. One of these, designated here as sulcus d, continues as a longitudinal groove into the mesencephalon. In Lepidosiren most neuronal perikarya are contained within a diffuse periventricular gray. However, 24 separate cell masses could be delineated. Six of these are primary efferent nuclei, six are primary afferent center, six nuclei are considered to be components of the reticular formation and the remaining six may be interpreted as "relay" nuclei. The distribution of the cell masses and their relations to the ventricular sulci were studied with the aid of the graphical reconstruction procedure termed tolopogical analysis (cf. Nieuwenhuys, '74, and fig. 11). This analysis yielded the following results. In the rhombencephalon the gray matter is arranged in four longitudinal columns or areas which have been termed the area ventralis, area intermedioventralis, area intermediodorsalis and area dorsalis. In many places the sulcus intermedius ventralis, the sulcus limitans and the sulcus intermedius dorsalis mark the boundaries between these morphological entities. These longitudinal areas coincide largely, but not entirely, with so-called functional columns of Herrick and Johnston. The most obvious incongruity is that the area intermediodorsalis contains, in addition to the nucleus of the solitary tract, two non-visceral sensory cell masses, namely the magnocellular and parvocellular vestibular nuclei. The four longitudinal zones cannot be distinguished in the mesencephalon nor can the sulcus limitans be recognized here. Functionally, however, the medial part of the tegmentum mesencephali may be considered the rostral extreme of the somatic motor column, whereas the remainder of the midbrain contains a number of somatic sensory centers.


Topological analysis of the brain stem of the crossopterygian fish Latimeria chalumnae. The ventricular sulcal pattern and the cellular structure of the brain stem of the single surviving crossopterygian species Latimeria chalumnae have been studied in transversely cut Nissl, Klüver-Barrera and Bodian stained serial sections. Five longitudinal sulci, the sulcus medianus inferior, the sulcus medianus superior, the sulcus intermedius ventralis, the sulcus limitans and the sulcus intermedius dorsalis could be delimited. The latter three of these sulci are confined to the rhombencephalon. The walls of the mesencephalon also display some longitudinal grooves, but none of these could be traced into continuity with any of the rhombencephalic sulci. Although the neuronal perikarya in many places show a diffuse arrangement, 27 cell masses could be delineated; eight of these are primary efferent nuclei, seven are primary afferent centers, seven nuclei are considered as components of the reticular formation, and the remaining five cell masses may be interpreted as "relay" nuclei. In order to study the zonal pattern of the brain stem, this structure was subjected to a topological analysis (cf., Nieuwenhuys, '74, and fig. 16). This analysis yielded the following results. The sulcus limitans divides the greater part of the rhombencephalon into a basal plate and an alar plate. In the basal plate the sulcus intermedius ventralis marks the boundary between an area ventralis and an area intermedioventralis. The area ventralis contains two somatic motor centers (i.e., the rostral end of the spinal motor column and the nucleus of IV) and most the entire rhombencephalic medial reticular formation. The latter may be primarily considered as a somatic motor coordinating center. The area intermedioventralis contains the visceral motor nuclei of V, VII, IX and X. However, the basal plate also harbours a number of non-motor centers, for example the sensory princeps nucleus of V and the inferior olive. The alar plate is subdivided by the sulcus intermedius dorsalis into an area intermediodorsalis and an area dorsalis. The area intermediolateralis is largely occupied by the common visceral sensory center of VII, IX and X; however, this area also contains a number of somatic sensory cell masses, as e.g. the nucleus descendens of V and the magnocellular vestibular nucleus. The area dorsalis is entirely occupied by two large lateral line centers. The cell masses in the isthmus region do not exhibit a clear-cut morphological pattern. As regards the mensencephalon, the medial part of the tegmentum, which contains a primary somatic motor center (the nucleus of III) and a somatic motor coordination center (the nucleus of the f.l.m.) may be considered a direct rostral continuation of the area ventralis. The remainder of the midbrain contains a number of somatic sensory centers of primary and higher order.


Origin, course and terminations of the rubrospinal tract in the pigeon (Columba livia). The red nucleus and its spinal projections in the pigeon (Columba livia) have been studied using both normal and experimental material. The cytoarchitecture of the nucleus is described on the basis of Nissl-stained sections and reveals an organization generally similar to that of mammals. The large neurons (40-50 mum) tend to be located dorsomedially and ventrolaterally at more caudal nuclear levels, while the small- and medium-sized neurons (15-35 mum) predominate at rostral levels. However, neurons of all sizes are present throughout the nucleus. Following lesions of the nucleus, the course of degenerating axons stained with the Fink-Heimer method has been traced throughout the brainstem and spinal cord. The rubrospinal tract crosses the midline, courses past the ventrocaudal aspect of the contralateral nucleus ruber, and then descends rostro-ventral and lateral to the nucleus tegmenti pontinus. In its caudal continuation the tract lies ventral to the brachium conjunctivum and the entering radix of the trigeminal nerve. It then assumes a ventrolateral position in the caudal brainstem before shifting to a dorsolateral position in the lateral funiculus of the spinal cord. Within the spinal grey the rubrospinal tract terminates in laminae V, VI and to a lesser extent VII. The possibility of a topographical organization of the nucleus was investigated with injections of horseradish peroxidase into brachial, thoracic and lumbar spinal cord. Regardless of the level of injection, labelled neurons of all sizes were present throughout the contralateral nucleus ruber, indicating the absence of an obvious topography.


Striate cortex and visual acuity functions in the cat. Using a two-choice visual discrimination paradigm, thresholds for size (gratings), parallelness (parallel vs. non-parallel lines), contour alignment (vernier offset), and angularity (polygon figures) were behaviorally determined in cats before and after ablations of portions of the geniculo-cortical system. Animals with a total loss of cortical area 17, and with a loss, in some cases, of up to 90% of areas 18 (with and without infringement into area 19), showed about a 30% reduction in grating acuity, a three-fold increase in parallelness and angularity thresholds, and a total loss of contour alignment ability. Control animals with ablations sparing area 17 showed no significant threshold changes. All animals were able to learn classic form discriminations postoperatively, but those with area 17-18 lesions at a somewhat slower than normal rate. Control procedures indicated that all tested discrimination capabilities did not depend on luminance differences between targets, local flux cues within the targets, or on the animals' use of residual portions of area 17 representing the peripheral visual field. Since the cat has multiple thalamo-cortical visual pathways, the results of the present study are consistent with the hypothesis that pathways parallel to the geniculo-striate system are capable of processing spatial information of considerable detail. The results also suggest, however, that the geniculo-striate system is uniquely necessary for the processing of the finest attributes of spatial contours.


The afferent connections and laminar distribution of cells in the cat striate cortex. A laminar distribution of different functional cell types in the striate cortex of the cat is drawn up from the visual responses of single cells recorded in 64 electrode penetrations in 38 cats. In summary, S cells were found to be concentrated in laminae 4 and 6; SH cells in laminae 2, 3 and 4; C cells in laminae 5 and lower 3; B cells in laminae 3 and upper 5 and cells with non-oriented receptive fields in lamina 4. In addition, the nature of afferent innervation to striate neurons was derived from the latency of the orthodromic response to electrical stimulation in the optic chiasm and optic radiations in 19 cats. An analysis of latency values allowed the afferent innervation to a cell to be classed as belonging either to fast or slow conducting streams in the population of dLGN axons and also permitted a decision to be made on whether or not the afferent path passed directly to the cell. Direct afferent innervation from the dLGN was not found to be confined to a single class of striate neuron. Instead, examples of cells with S, SH, C, B and non-oriented receptive fields all had orthodromic latencies that met the requirement for direct innervation. Instances of cells with orthodromic latencies suggestive of indirect innervation were also found for most receptive field classes but these cells were encountered less frequently than those with a direct afferent input. It is argued that a variety of different cell types may act as first order neurons in the striate cortex and that cells occurring at later stages in the sequence of cortical processing may have been incompletely studied because they are more difficult to stimulate either visually or electrically.


An electron microscope study of synaptic contacts in the abdominal ganglion of Aplysia californica. The fine structure of the abdominal ganglion of Aplysia californica has been studied in preparations fixed by immersion in aldehydes, either directly or after a survival of a few hours in artificial sea water. The central core of neuropil is surrounded by a rind of neuronal cell bodies floating in a subcapsular space containing a loose meshwork of neuronal and glial processes, separated by wide extracellular spaces. Large primary processes with deeply infolded membranes leave the neuronal perikarya and enter the neuropil where they branch into smaller processes containing either neurofilaments, neurotubules or both. Some have the appearance of initial segments. The neuropil is not a homogeneous structure. Rather, four types of zones can be distinguished: (1) zones of fibers of passage coursing together in the neuropil and making few synaptic contacts: (2) zones of neurosecretory fibers containing large granules and dense-core vesicles, again making few synaptic contacts: (3) zones with a great variety of synaptic contacts between medium size and small profiles; and (4) glomerular zones. The differentiated membranes of the synapses are characterized by a slight increase in density and by being regularly parallel to each other. Presynaptic densities are sometimes quite prominent but specialized dense cytoplasmic opacities have never been seen bordering the postsynaptic membranes, i.e., all synapses are of the symmetrical type. Interlemmal opacities vary considerably in density. In zone 3, the synaptic vesicles are of several sizes, are round, oval or flat, and are either clear or filled with different types of dense material. The population of vesicles within a single profile may consist either of a homogeneous group of similar vesicles or of various mixtures of two or three kinds of vesicles. In profiles with mixtures of clear and large dense-core vesicles, it is often only the clear vesicles which agglomerate towards the differentiated membranes. In such cases the large dense-core vesicles lie as a peripheral halo around the clear vesicles. Here, and especially in other large neuronal profiles not forming contact in the plane of section, they can be seen to associate specifically with mitochondria and glycogen. It is proposed that they do not contain neurotransmitters but are related to mitochondrial activities such as the storage of ATP or the movement of calcium ions. In profiles with mixtures of clear and small dense-core vesicles, both types of vesicles often touch the presynaptic membrane, suggesting the release of two transmitters or of a modulator or neurohormone with a transmitter, by a single terminal. Serial synapses are present in this zone. The glomerular zones contain small profiles forming many synaptic contacts, some of which are arranged in such a way as to suggest the existence of "reciprocal" serial synapses.


The rabbit and the cat: a comparison of some features of response properties of single cells in the primary visual cortex. Receptive field characteristics of single cells in primary visual cortex of rabbit were studied. Seventy-two percent of cells were found to be orientation selective, and the remainder had concentric, uniform, movement selective or pure direction selective receptive fields. Single cells were also recorded from primary visual cortex of cat to permit a comparison of visual cortical organization in cats and rabbits. Laminar organization of receptive field types was observed in rabbits which was similar in most respects to that described in the cat. Although the major categories of orientation selective cells (simple, complex, hypercomplex) were similar for both cat and rabbit, many differences emerged: (I) tuning of orientation selectivity was narrower in cats than in rabbits; (II) units which preferred oblique orientations were less frequently represented in rabbits than in cats; (III) orientation preferences appeared to be arranged in clusters in rabbit cortex; in rabbits we found no evidence of the columnar organization of orientation selectivity which characterizes cat visual cortex. A comparison of our data with those previously reported for mouse, rat, hamster and opossum visual cortex suggest that mammals in which a significant proportion of visual cortical cells are not orientation selective have in common certain patterns of cortical organization involving a less precise and less specilized representation of stimulus orientation.


Spiral ganglion cell counts in an age-graded series of rat cochleas. Spiral ganglion cells in the cochleas of Sprague-Dawley rats in various age groups were counted in order to assess the extent and location of cell degeneration with age. Cells in every tenth section of serially sectioned plastic embedded cochleas were counted in the light microscope. The median cell number for the 1- to 2-month-old animals was 15,800 cells. This number was first seen to be significantly reduced (-14%) in the 23-month-old animals. At 27 to 29 months the ganglion cell number was reduced by 20%, while at 33 to 34 months there was a 17% loss. Losses were found throughout the length of the ganglion with the greatest losses at the lower basal and apical ends. In the oldest group, these losses amounted to 28% and 33%, respectively. Type II ganglion cells first showed a significant decrease in number in the 27- to 29-month-old group, when a 32% loss was seen. The same loss was seen in the 33- to 34-month-old group. Unlike the type I cells which are lost throughout the length of the ganglion, type II cells were not significantly reduced in number at the basal end, but decreased by as much as 42% in the middle and apical regions.


Development of the diencephalon in the rat. IV. Quantitative study of the time of origin of neurons and the internuclear chronological gradients in the thalamus. Groups of pregnant rats were injected with two successive daily doses of 3H-thymidine from gestational days 13 and 14 (E13 + 14) until the day before birth (E21 + 22). With this progressively delayed comprehensive labelling procedure we determined the time of origin of neurons in the nuclei of the epithalamus, thalamus, and ventral thalamus. The zona incerta, subthalamic nucleus, reticular nucleus, posterior nucleus, and ventral lateral geniculate nucleus are composed of the earliest arising neurons (E13, or before, to E15). The neurons of the lateral habenular nucleus are produced between days E13--16. The neurons of the medial geniculate and lateral geniculate nuclei, the ventrobasal and ventrolateral complexes, and the nucleus lateralis, pars posterior, arise rapidly on days E14--15; the medial geniculate nucleus with a peak on day E14, the others with a peak on day E15. Neurons of a group of nuclei, with ill-defined boundaries medial to the sensory relax nuclei, arise apparently on days E15--16, with a peak on day E15; these may represent the intralaminar nuclei. The next group is generated on days E15--16 but with peak formation time on day E16; this includes the anteroventral, anterodorsal, anteromedial and mediodorsal nuclei. The rhomboid, reuniens and paratenial nuclei, and the paraventricular nucleus, pars anterior, arise next (E16--17). The medial habenular nucleus forms last and over a protracted period (E15--19). With their lengthy generation time the lateral and medial habenular nuclei resemble more the nuclei of the hypothalamus than the nuclei of the dorsal thalamus.


Development of the diencephalon in the rat. V. Thymidine-radiographic observations on internuclear and intranuclear gradients in the thalamus. Groups of pregnant rats were injected with two successive daily doses of 3H-thymidine from gestational days 13 and 14 (E13 + 14) until the day before birth (E21 + 22). Internuclear and intranuclear cytogenetic gradients were examined in radiograms of the thalamus sectioned in the coronal, sagittal and horizontal planes. There was a precise and segregated lateral-to-medial gradient between and within the habenular nuclei. In the ventral thalamus the reticular nucleus had a lateral-to-medial gradient, the subthalamic nucleus a laterodorsal-to-medioventral gradient. There was a caudal-to-rostral gradient between the medial geniculate and dorsal lateral geniculate nuclei, and between the pars posterior and pars anterior of the lateral nucleus. A clear intranuclear gradient could not be detected in the sensory relay nuclei with the exception of the medial geniculate nucleus. A lateral-to-medial internuclear gradient was seen between the relay nuclei and the intralaminar nuclei, and between the latter and some of the midline nuclei. On the basis of a consideration of the time of origin and time span of production of neurons of various thalamic nuclei, and taking into account some of the recognizable internuclear and intranuclear gradients, the thalamus was divided into five principal cytogenetic components; the epithelamus, the ventral thalamus, the dorsal thalamus, the medial thalamus, and the posterior thalamus. The epithalamic nuclei form over a protracted period resembling the nuclei of the hypothalamus. The nuclei of the ventral thalamus are generated early and over a relatively long period. The dorsal thalamus consists of the relay nuclei and the intralaminar nuclei; they form rapidly and ahead of the medial thalamus. The medial thalamus was subdivided into the earlier-forming anteromedial nuclei and the latest-forming midline nuclei. The posterior thalamus was not examined in detail.


Development of the diencephalon in the rat. VI. Re-evaluation of the embryonic development of the thalamus on the basis of thymidine-radiographic datings. The development of the thalamus was examined in normal and X-irradiated embryos from day 13 (E13) to the day before birth (E22). The differentiating, radioresistant neurons of the lateral habenular nucleus, derived from a portion of the superior neuroepithelial lobule (SL1), were settling by day E15 and by this time the habenulopeduncular tract was forming. The neurons of the reticular nucleus, derived from the middle neuroepithelial lobe, began to settle on day E15 but a massive migration was still evident on day E16. Adjacent to the reticular nucleus the internal capsule appeared on day E16; this fiber bundle seemed to be continuous with fibers embedded in the first transitory zone of cells issuing from the dorsal neuroepithelial lobe. Because of the immaturity of the neocortex at this time, it was postulated that thalamocortical fibers of the dorsal thalamus are the earliest components of the internal capsule. By day E17 all the sensory relay nuclei of the thalamus were recognizable and it was assumed that the second transitory zone issuing from the receding dorsal neuroepithelial lobe contained the neurons of the later forming intralaminar nuclei. Suggestive evidence was obtained that the late arising neurons of the medial thalamus (the anterior nuclei, the mediodorsal nucleus, and some or all of the midline nuclei) originate in a portion of the superior neuroepithelial lobule designated as SL2. Our present and previous studies showed that the major divisions of the hypothalamus and thalamus are derived embryonically from distinguishable parts of the third ventricle neuroepithelium. This implies the te third ventricle neuroepithelium has a "mosaic" organization and suggests that the fate of hypothalamic and thalamic neurons may be determined to some extent while their precursors are still proliferating.


Treatment of lentigo maligna and lentigo maligna melanoma. The results of treatment of 42 cases of lentigo maligna and 16 of lentigo maligna melanoma at the New York University Medical Center was reviewed. The recurrence rate after surgical excision of 22 lesions of lentigo maligna was 9% (2/22), but after treatment of 20 such lesions with destructive techniques (X rays, curettage-electrodesiccation, cryosurgery), it was 35% (7/20). Of 11 cases of lentigo maligna melanoma that were excised, none recurred locally, but fatal metastases ensued in one case. Five patients who were eventually classified as having lentigo maligna melanomas had been treated by destructive techniques. In four of them there were local recurrences and in two, metastases as well; the fifth patient had metastases without local recurrence. On the basis of this review of these 58 cases, we conclude that surgical excision and careful histologic study of step sections through the entire lesion insure accurate diagnosis and provide the highest cure rates for lentigo maligna and lentigo maligna melanoma.


Narrow-band AP latencies in normal and recruiting human ears. Derived narrow-band action potential latencies increase monotonically with decreasing central frequency, and can be interpreted as reflecting the traveling wave delay in the cochlea. It was found that, for recruiting human ears with average flat hearing losses around 40 dB, this accumulating latency increase was smaller than for normal ears. A comparison of 15 normal ears and 37 recruiting ears showed, however, that in only half of the recruiting ears this difference was significant. These recruiting ears were therefore divided in two groups based on the waveform of the narrow-band action potential AP, which correlated well with the subdivision according to latency. The findings have been explained on the basis that latency of the narrow-band APs is not determined solely by the mechanical traveling-wave delay, but also by the response time of the (second?) cochlear filter. When this filter broadens, one expects a decrease in its impulse response time. Since this impulse response time. Since this impulse response depends on the sum of the high- and low-frequency slope values of the cochlear filter, one expects only a latency decrease when the steep high-frequency slope also becomes more shallow. A support for the influence of the response times of the cochlear filter is found in the narrow-band AP latencies for restricted cochlear losses (e.g., in a 4-kHz noise dip). It appears that the latency in that area actually is shorter than for the higher central frequencies, a fact which cannot be explained solely on the basis of a traveling wave phenomenon.


Lateralization of tonal signals which have neither onsets nor offsets. In order to ascertain the special importance of binaural cues conveyed in the transient portions of dichotic signals, thresholds for interaural differences of time (delta t) and intensity (delta I) were studied using stimuli whose onsets and offsets were masked. Intense noise was used to mask all portions of each experimental trial except for the two intervals of a two-interval, forced-choice detection task. During the intervals,  the noise was turned off with decay-rise times of 10 ms. What remained were tones whose interaural phase or intensity was different for intervals one and two. Performance was compared to control conditions which used unmasked gated sinusoids. For longer durations, detection without onsets and offsets was about as good as that with no masker. For the shorter signals, detection without transients was poorer than with standard lateralization, but this is attributed to forward and backward masking which reduced the effective durations of those stimuli. The ability to detect interaural differences of time with the onsets and offsets masked was extended to conditions in which the decay times of the noise were 100 ms. Performance here was slightly worse, but not by so much as to change the basic result. This is interpreted as showing that performance with the faster decay-rise times was not a product of momentary undershoots in neural following, but depended, rather, upon a true encoding of the interaural information in the stimulus fine-structure.


A stereo-fiberscope with a magnetic interlens bridge for laryngeal observation. A stereoscopic method of observation of the larynx and the pharynx during speech utterances has been devised, making use of fiber-optic cables and a magnetic bridge. The cables are inserted via the subject's nostrils. The bridge makes the two objective lenses at the tips of the cables abut within the pharynx near the uvula, and the two images viewed through the separate lenses at the prescribed mutual distance are recorded on each frame of a 16-mm film side by side for computer processing of the three-dimensional data.


Automatic speech recognition using psychoacoustic models. An approach to automatic speech recognition is described, which, in a straightforward way, follows the concept of (1) preprocessing in terms of auditory parameters and (2) subsequent classification and recognition. The preprocessing system has been realized in analog hardware, while recognition is carried out on a digital computer. In the preprocessing system, the essential psychoacoustic principles of the perception of loudness, pitch, roughness, and subjective duration are implemented with some approximation. The system essentially consists of 24 bandpass filters, nonlinear transformation of each filter output into specific loudness and specific roughness, and final transformation of these parameters into total loudness, total roughness, and three spectral momenta. As a means to further reduce the information flow, continuous selection of dominant parameters is also considered on the basis of psychoacoustic data. The subsequent recognition process is mainly characterized by (1) discrimination between speech and silent periods, (2) detection of syllable peaks and classification of syllable nuclei, and (3) assumption of syllable boundaries and classification of consonant clusters. Though the entire system as yet is far from being complete and perfect, the present results indicate that the concept provides a systematic and promising way towards automatic recognition of continuous speech.


The relationship between collagen and ultrasonic attenuation in myocardial tissue. The relationship between ultrasonic attenuation and collagen content is examined in hearts from normal dogs and in hearts from dogs subjected to ischemic injury by coronary occlusion as an approach toward elucidating the physical mechanisms responsible for the attenuation of soft tissue. Increased ultrasonic attenuation is shown to correlate well with increased collagen concentration determined biochemically in regions of ischemic injury studied 2, 4, and 6 weeks following occlusion. Extrapolation of experimentally determined relationship between attenuation and collagen concentration suggests that collagen is responsible for not more than 15% of the attenuation observed in normal myocardium. These results indicate that collagen appears to be the principal determinant of the elevated attenuation detected in regions of myocardial infarction, but is apparently not the primary determinant of the attenuation of normal myocardium.


Auditory detection of a single gap in noise. The detection threshold of a single gap in white noise was measured as a function of the gap duration. The results can be described with an auditory integration time of about 25 ms. This value is much larger than the 3--4 ms usually found in experiments on auditory temporal integration. The discrepancy shows that a system theoretical description of the detection of arbitrary amplitude changes in noise in terms of a modulation transfer function, fails to explain the detection of a single gap.


Detectability of a pulsed tone in the presence of a masker with time-varying interaural correlation. Detectability of a filtered probe tone (250, 500, or 1000 Hz) was measured in the presence of a narrow-band Gaussian masker centered at the signal frequency. The signal was interaurally phase-reversed (Spi), and the masker's interaural correlation varied sinusoidally between +1.00 (NO) and -1.00 (Npi) at a varaible rate (fm = 0--4 Hz). The signal was presented at various points on the masker's modulation cycle. For 0-Hz modulation (fixed interaural correlation) signal threshold decreased monotonically as the masker's interaural correlation was changed from -1.00 to +1.00 (by a total of about 20, 16, and 8 dB, respectively, for 250-, 500-, and 1000-Hz signals). For fm greater than 0 the function relating signal threshold to the masker's interaural correlation at the moment of signal presentation became progressively flatter with increasing fm for all signal frequencies. For fm = 4 Hz the function was flat; there was no measurable effect of masker interaural correlation on signal detectability. Estimates of minimum binaural integration time based on these data ranged from 44--243 ms, supporting previous studies which have noted the binaural system's relative insensitivity to dynamic stimulation. Additionally, the estimated time constants were approximately twice as large at 250 Hz as at 500 Hz, indicating observers could follow binaural fluctuations better at 500 Hz. The time-constant estimates at 1000 Hz were not suggiciently reliable to permit comparisons with the lower-frequency data.


Some experiments on the sound of silence in phonetic perception. The results of several experiments demonstrate that silence is an important cue for the perception of stop-consonant and affricate manner. In some circumstances, silence is necessary; in others, it is sufficient. But silence is not the only cue to these manners. There are other cues that are more or less equivalent in their perceptual effects, though they are quite different acoustically. Finally, silence is effective as a cue when it separates utterances produced by male and female speakers. These findings are taken to imply that, in these instances, perception is constrained as if by some abstract conception of what vocal tracts do when they make linguistically significant gestures.


The role of medial consonant transitions in word perception. In VCV nonsense forms (such as /epsilondepsilon/, while both the CV transition and the VC transition are perceptible in isolation, the CV transition dominates identification of the stop consonant. Thus, the question arises, what role, if any, do VC transitions play in word perception? Stimuli were two-syllable English words in which the medial consonant was either a stop or a fricative (e.g., "feeding" and "gravy"). Each word was constructed in three ways: (1) the VC transition was incompatible with the CV in either place, manner of articulation, or both; (2) the VC transition was eliminated and the steady-state portion of first vowel was substituted in its place; and (3) the original word. All versions of a particular word were identical with respect to duration, pitch contour, and amplitude envelope. While an intelligibility test revealed no differences among the three conditions, data from a paired comparison preference task and an unspeeded lexical decision task indicated that incompatible VC transitions hindered word perception, but lack of VC transitions did not. However, there were clear differences among the three conditions in the speeded lexical decision task for word stimuli, but not for nonword stimuli that were constructed in an analogous fashion. We discuss the use of lexical tasks for speech quality assessment and possible processes by which listeners recognize spoken words.


Detection versus discrimination of brief tones by cats with auditory cortex lesions. In recent years, a number of investigators have provided evidence that the auditory cortex has a critical role in both the detection and discrimination of brief sounds. Dogs and humans with lesions of the neocortical auditory centers have been reported to exhibit significantly elevated detection thresholds for signals shorter than 16 ms in duration. In tests of frequency discrimination, the same subjects also exhibited severe deficits whenever tonal signals were less than 20--40 mn in lengths. In the present report, we present evidence brief tones. Operated cats, while exhibiting normal difference limens for 1-kHz tones of 100-ms duration, have significantly elevated limens for discriminating tones of 8- and 2-ms duration. With further testing, the same operated cats can be shown to have normal absolute thresholds for detecting brief tones.


Tone-segregation by phase: on the phase sensitivity of the single ear. A monaural complex tone is synthesized from 12 harmonically related pure tones, played in phase. In each of 12 segments, one of the tones (the target) is played out of phase so that the sequence of targets is increasing or decreasing in frequency. If the target is at least 30 degrees out of phase, the targets are perceptually segregated. This tone-segregation by phase raises doubts concerning several current theories of pitch perception. The phenomenon is conjectured to be caused by the ear's nonlinear compressive transfer characteristic or by a temporal analysis of the stimulus.


Discrimination of uniform spectrum pulse sequences. Random polarity-modulated sequences were produced with a uniform short-term spectrum over defined sampling intervals by a method described by Pierce, Lipes, and Cheetham [J. Acoust. Soc. Am. 61, 1609-1621 (1977)]. These are identified as PLC sequences. By contrast, unconstrained random polarity-modulated pulse trains with a constant interpulse interval may depart from a short-term uniform spectrum. It is shown that listeners can clearly discriminate between PLC sequences and unconstrained random sequences, and can discriminate among different PLC sequences. This discrimination is more nearly related to the statistical redundancy of the PLC sequences. This discrimination is more nearly related to the statistical redundancy of the PLC sequences than to their run-length distribution. Such discrimination is relatively resistant to moderate degrees of temporal jitter and is obtained with other forms of information coding. Discrimination of PLC sequences is presumably based upon phase information.


Children's understanding of monosyllabic nouns in quiet and in noise. A four-alternative, forced choice adaptive procedure was used to measure the lowest intensity at which children could identify monosyllabic nouns that had been standardized to be understandable (at comfortable listening levels) to inner city, 3-year-old children. Results showed no age-related performance changes when the words were presented against a 12-talker babble or against filtered noise. In quit, however, performance improved between the ages of 5 and 10 years. Performance of children with learning problems was poorer than performance of children achieving normal school progress, even though clinical measures of auditory sensitivity showed no differences. Results are discussed in terms of "semantic closure" skills of children.


Cochlear macromechanics: time domain solutions. In this paper we report on a new method of solving a previous derived, two-dimensional model, integral equation for basilar membrane (BM) motion. The method uses a recursive algorithm for the solution of an initial-value problem in the time domain, combined with a fast Fourier transform (FFT) convolution in the space domain at each time step. Thus, the method capitalizes on the high speed and accuracy of the FFT yet allows the BM to have nonlinear mechanical properties. Using the new method we compute (linear) solutions for various choices of model parameters and compare the results to the experimental measurements of Rhode. [J. Acoust. Soc. Am. 49, 1218-1231 (1971)]. We also demonstrate the effect of including longitudinal stiffness along the BM and conclude that it is useful in matching the high-frequency slope as measured by Rhode.