the facilitation or inhibition of gastrointestinal motility due to stress has been 
 previously reported ( 1 , 2 ) . as gastrointestinal motility
is partially reflected by egg activity ( 3 , 4 ) , the effects 
 of stress on the epigastric , supraumbilical and infraumbilical egg data can be correlated 
 with anxiety scores .
our previous study demonstrated that the local differences in the power 
 content during 16-location egg were more clearly shown at rest , during the postprandial 
 state and during the mirror drawing test ( mdt ) ( 5 ) . 

furthermore , we demonstrated the epigastric egg inhibition ( seen in 3 cpm activity ) and 
 infraumbilical egg facilitation ( seen in 6 cpm activity ) during mdt stress in a numerical 
 comparison of the power content ratio of the mdtr and topographic egg mapping 
 of mdtr ( power content during mdt / power content at rest ) ( 6 ) .
therefore , in the present study , we compared the effects of 
 mdt - related stress on each of the 16 locations of egg using the power content ratio of the 
 mdtr to clarify the correlation between stress and egg , which partially 
 reflects gastrointestinal motility ( 3 , 4 , 6 ) .
this project was conducted under the approval of the ethics committee of niigata 
 university , faculty of medicine ( project no . 179 ) .
informed consent was obtained from all of 
 the subjects after explanation about the informed consent immediately prior to the egg 
 recording .
there were 58 subjects , ( 52 
 males and six females ) , with 23 of the subjects ranging in age from 2038  years ( 23.1  1.0 , 
 n=23 ) , while the age of other 35 subjects was not known .
the methods used 
 for recording and analyzing eggs were the same as those used in the previous studies ( 7 , 8) .
briefly , 
 unipolar eggs were recorded from 16 locations ( channels , ch ) from the thoraco - abdominal skin 
 surface ( fig .
location of the electrodes . superimposed images of the body and the location of the 
 16 electrodes on the thoraco - abdominal body surface based on the xiphoid process , 
 costal arch , and iliac line .
the numbers ( 1 - 16 ) by the filled 
 circles indicate the roughly averaged location of the electrodes . the length of 
 x0~xmax was assumed to be 32  cm , and that of 
 y0~ymax 36  cm based on the superimposed body lines ( 5 ) . 

2012 ; 48(23 ) : 4757 ) ( 6 ) . ) , using a reference electrode on the right leg .
the amplifier was a modified 
 electroencephalographic ( eeg ) amplifier , with time constant set at 5 sec , with a high cut at 
 0.5  hz , a low cut of 6 dboct and a high cut of 12 dboct , ( biotop 
 6r 124 , nec - sanei , japan ) .
after cleaning the skin with ethanol , electrode cream was 
 applied to the disc electrode for the eeg ( diameter=11  mm ) .
resting eggs were recorded for about 20  min , in subjects who had 
 fasted for at least eight hours , and were sampled every 128 sec ( 1 file ) . after recording 
 the resting control data , subjects were exposed to the stress of the mdt .
the mdt involves 
 tracing the cue figure of a metal star , reflected onto a mirror with an electric pen , which 
 gives a click alarm when the tracing runs off the edge of the star ( error ) .
the mdt stress 
 was applied for about 5  min to obtain 23 egg files .
compiled running spectra were obtained 
 after the files were analyzed using the maximal entropy method ( mem ) .
the spectral frequency 
 readings were classified into five groups : the 1-cpm group ( 02.4 cpm ) , 3-cpm group ( 2.54.9 
 cpm ) , 6-cpm group ( 5.07.4 cpm ) , 8-cpm group ( 7.59.9 cpm ) and 10-cpm group ( 10.012.9 cpm ) . 

ensemble means were obtained during rest , during the stress of the mdt , and after the mdt . 
 with regard to the egg parameters , this study focused on the power content ratio of 
 mdtr for each channel .
the egg power content ratio of electrode locations1 cpm ( 02.4)3 cpm ( 2.54.9)6 cpm ( 5.07.4)8 cpm ( 7.59.9)10 cpm ( 10.012.9)ch.22.17  .580.95  .590.52  .077130.86  .0640.86  .12ch.51.95  .2610.90  .05440.89  .060140.96  .0890.84  .10ch.81.71  .161.01  .066121.08  .10150.84  .0730.83  .096ch.101.76  .181.11 
.07151.04  .089160.85  .0780.76  .088ch.111.59  .141.36  .1461.03  .091170.84  .0910.64  .079ch.121.64  .171.22  .09070.96  .074180.82  .0880.67  .096ch.131.63  .191.21  .07481.03  .084190.74  .0760.66  .081ch.141.48  .131.30  .1090.99  .081200.84  .121.28  .57ch.151.32  .1121.17  .076101.04  .073100.87  .100.79  .11ch.161.34  .1131.19 
.092111.04  .077220.81  .0730.69  .070the effect of the mdt on the power content ratio ( mdtr , 
 n=5258 , means  s.e.m . ) .
46 , 47 , 48 , 49 , 410 , and 1314 , 
 p<0.01 . 1315 , 1316 , 1317 , 1318 , 1319 , 1320 , 1321 , and 
 1322 , p<0.001 .
lists the figures for the epigastric 2 , 5 and 8 channels and the 
 infraumbilical 1216 channels found in our previous studies for simplicity ( 5 , 6 ) .
the anxiety 
 scores were estimated using the hads ( hospital anxiety and depression scales ) ( 9 , 10 ) .
the 
 electrode positions were represented by two - dimensional standard coordinates , xi 
 and yi , and a spectral peak at a certain electrode position was expressed as 
 zi = ( xi , yi ) ( 7 , 
 8 , 11 , 12 ) .  
superimposed images of the body and the location of the 
 16 electrodes on the thoraco - abdominal body surface based on the xiphoid process , 
 costal arch , and iliac line .
the numbers ( 1 - 16 ) by the filled 
 circles indicate the roughly averaged location of the electrodes . the length of 
 x0~xmax was assumed to be 32  cm , and that of 
 y0~ymax 36  cm based on the superimposed body lines ( 5 ) . 

2012 ; 48(23 ) : 4757 ) ( 6 ) . the effect of the mdt on the power content ratio ( mdtr , 
 n=5258 , means  s.e.m . ) .
46 , 47 , 48 , 49 , 410 , and 1314 , 
 p<0.01 . 1315 , 1316 , 1317 , 1318 , 1319 , 1320 , 1321 , and 
 1322 , p<0.001 .
the mean and standard errors ( sem ) were calculated , and the student 's t 
 test was used to determine the level of statistical significance .
the epigastric ( ch.2 , 5 and 8) and infraumbilical ( ch.1216 ) power content ratio of the 
 mdtr of five spectral frequencies in addition to umbilical channels 10 and 11 
 are shown in table 1 .
the power content ratio of 
 mdtr of 3- and 6 cpm in the epigastric channels was generally , significantly 
 lower than that of the infraumbilical channels .
the significant linear correlations 
 ( p<0.05 ) between the anxiety scores and power content ratio of 
 mdtr are shown in table 
 2table 2 .
the linear correlation parametersprch.2 ( 3 cpm)1.610.0460.071ch.10 ( 6 cpm)1.310.0130.11ch.11 ( 6 cpm)1.110.0330.080ch.13 ( 6 cpm)1.180.0370.077ch.15 ( 6 cpm)1.710.0080.123ch.16 ( 6 cpm)1.280.0380.076tabulation of the the significant linear correlation parameters 
 ( p<0.05 ) between the anxiety scores and the power content ratio of 
 the mdt to that at rest ( mdtr ) . and fig .
2 . a : the correlation between the anxiety scores and the egg power content ratio of 3 
 cpm .
the linear correlation between the anxiety scores ( y axis ) and the power content 
 ratio ( mdtr ) of 3 cpm of epigastric channel 2 ( x - axis ) .
slope (  ) = 1.61 , 
 p = 0.046 , and r = 0.071 .
b : the correlation between 
 anxiety scores and the egg power content ratio of 6 cpm .
the linear correlation 
 between anxiety scores ( y - axis ) and the power content ratio ( mdtr ) of 6 
 cpm of infraumbilical channel 15 ( x - axis ) .
slope = 1.71 , p = 0.008 , 
 and r = 0.123 .. the slope of the ch.2 correlation ( 3 cpm ) was negative ( fig .
2a ) and the slopes of ch.10 , 11 , 13 , 15 , and 16 ( 6 cpm ) were 
 positive ( fig .
tabulation of the the significant linear correlation parameters 
 ( p<0.05 ) between the anxiety scores and the power content ratio of 
 the mdt to that at rest ( mdtr ) .  
a : the correlation between the anxiety scores and the egg power content ratio of 3 
 cpm .
the linear correlation between the anxiety scores ( y axis ) and the power content 
 ratio ( mdtr ) of 3 cpm of epigastric channel 2 ( x - axis ) .
slope (  ) = 1.61 , 
 p = 0.046 , and r = 0.071 .
b : the correlation between 
 anxiety scores and the egg power content ratio of 6 cpm .
the linear correlation 
 between anxiety scores ( y - axis ) and the power content ratio ( mdtr ) of 6 
 cpm of infraumbilical channel 15 ( x - axis ) .
it is well known that egg records gastrointestinal electrical activity or myoelectric 
 activity , which reflects some of the motility as power content ( 3 , 4 ) .
the power content ratio or 
 the normalization of egg change , mdtr ( power content during mdt / power content 
 at rest ) reflects the real change of the local egg for each electrode as demonstrated in 
 topographic egg maps ( 6 ) .
it is also well known that stress influences the gastric and colonic activity measured with 
 egg .
in fact , stress induces dual excitatory and inhibitory effects that can be observed 
 with egg .
cold pressor test stress , interviews and performing arithmetic calculations 
 increased the colonic egg ( 13 ) .
electric shock 
 significantly decreased the percentage of the 3 cpm frequency and tachyarrhythmia ( % ) 
 component of the egg , but forehead cooling increased the percentage of the 3 cpm frequency 
 ( 14 ) .
the induction of similar gastric inhibition 
 or facilitation by stress has been reported using manometry ( 14 , 15 , 16 , 17 ) .
we have previously reported the 
 effects of the acute stress of mdt on the gastric and colonic facilitation or inhibition 
 with egg .
however , mdt stress did not appear to exert effects on the intestinal egg activity 
 ( 6 , 8 , 12 ) .
it is generally accepted that the normal gastric spectral activity of egg is 3 cpm ( 3 , 18 , 19 ) .
however , the gastric and colonic egg activity 
 includes both 3- and 6- cpm egg activity according to gastrectomy and colectomy studies 
 ( 7 , 20 , 21 , 22 , 23 , 24 ) . 

therefore , the infraumbilical 6 cpm egg activity in this study is considered to reflect the 
 colonic myoelectric activity . both colonic facilitation and inhibition
however , the finding of a 
 significantly higher power ratio of the mdtr of the infraumbilical 3 cpm than 
 that in the epigastric recording during mdt suggested that the mdt stress inhibited gastric 
 egg and facilitated colonic egg .
in addition , topographic egg maps drawn according to the 
 power content ratio of the mdtr and the absolute power ratio of 
 mdtr supported this idea ( 6 ) . similar 
 findings of colonic facilitation have been reported with manometry ( 13 , 25 , 26 , 27 , 28 , 29 ) .
mdt - related stress significantly increased bowel evacuation 
 frequency , while it is known that depressed patients tend to be constipated ( 30 ) .
, a linear correlation with a negative slope was found between the 
 anxiety scores and the mdtr of 3 cpm egg of channel 2 in this study ( table 2 , fig . 

, the correlation between the anxiety scores and the 3 cpm 
 mdtr was not calculated in channel 2 ( ch2 ) alone , and the mean of 
 mdtr for channels 3 , 4 , 5 , and 6 channels was defined as the epigastric ch1 
 ( 8 , 12 ) .
a 
 significant linear correlation was not found between the anxiety scores and the 3 cpm of ch1 
 mdtr ( 12 ) . a significant linear 
 correlation with a positive slope
was also found in the mdtr of 6 cpm of 
 umbilical channels 10 and 11 ( table 2 ) . 

similarly , the infraumbilical ch3 was calculated using the mean of channels 12 , 13 , and 14 
 ( 12 ) . however
, a linear correlation with a positive 
 slope was found between the anxiety scores and infraumbilical 6 cpm of ch3 mdtr 
 6 cpm ( 12 ) and channel 13 ( one of the ch3 
 substituents ) in this study in addition to channel 15 ( fig .
2b ) and channel 16 ( table 2 ) . a 
 significant linear correlation with a positive slope
was also found in the mdtr 
 of 6 cpm of umbilical channels 10 and 11 ( table 
 2 ) .
the locations of channels 10 and 11 may correspond to the right and left 
 flexure of the colon .
it is has been suggested that various stressors depress stomach contractility and emptying , 
 and facilitate colonic motility , transit and defecation through the limbic , hypothalamic and 
 autonomic nervous system via rf - r2 ( corticotrophin - releasing factor receptor and crf - r1 , 
 respectively ( 32 , 33 , 34 , 35 ) .
our egg findings in human subjects provide further supports for these studies 
 ( 6 ) .
finally , the present results further support the idea that mdt stress inhibits stomach 
 motility and facilitates colonic motility .
the author does not have any financial relationship with the organization that sponsored 
 the research .
 electrogastrograms ( eggs ) were recorded at 16 locations on the thoraco - abdominal 
 surface at rest and then both during and after the acute stress of performing the mirror 
 drawing test ( mdt ) . a significant linear correlation with a negative slope was found 
 between the anxiety scores and the ratio of the power content during mdt to the power 
 content at rest ( r ) ( mdtr1 ) of the 3 cpm component from the epigastric channel 
 2 recording . 
 in contrast , significant linear correlations with positive slopes were found 
 between the anxiety scores and mdtr1 of the 6 cpm component of the recordings 
 from the infraumbilical channels ( channels 13 , 15 , and 16 ) . 
 the epigastric 3-cpm egg 
 activity reflects gastric myoelectric activity , while the infraumbilical 3- and 6-cpm 
 activity reflects that of the colon . 
 therefore , these results seem to further support the 
 previous report of the inhibition of gastric egg by stress and the stress - mediated 
 facilitation of colonic egg ( homma s , j smooth muscle res . 2012 ; 48(23 ) : 4757 ) . 
Introduction
Methods
Results
Discussion
Conflict of interest