Mydriasis pupil) or overactivity of the sympathetic nervous system (SNS). Pupil diameter also increases in reaction to cognitive tasks requiring memory and attention, and this phenomenon is used as an indicator of mental activation (‘arousal’) in psychophysiological experiments . Natural release of the hormone oxytocin can cause mild to moderate mydriasis. Parasympathetic fibers travel with cranial nerve III, the oculomotor nerve, to innervate the circular layer of muscle of the eye (sphincter pupillae). Damage to this nerve typically manifests itself as mydriasis, because the sympathetic supply to the pupil, which causes mydriasis, remains unaffected, and therefore unopposed. Multiple central nervous system
Sum of normally distributed random variables distribution are obvious by comparison with the standard normal distribution. Sum of normally distributed random variables In probability theory, calculation of the sum of normally distributed random variables is an instance of the arithmetic of random variables, which can be quite complex based on the probability distributions of the random variables involved and their relationships. This is not to be confused with the sum of normal distributions which forms a mixture distribution. If "X" and "Y" are independent random variables that are normally distributed (and therefore also jointly so), then their sum is also normally distributed. i.e., if then This