PUPILLARY DILATATION INDUCED BY STIMULATION OF AMYGDALOID NUCLEI

Abstract

1) Through stimulation of the medial principal nucleus of amygdala proper (T of Völsch), most remarkable pupillary dilatation was called forth generally in both sides and in response to unilateral stimulation. Exophthalmus, abduction of eyeballs, retraction of the nictitating membranes, and nystagmus of small amplitude were also manifested. 2) Through stimulation of the lateral principal nucleus of amygdala proper (M of Völsch), there appeared in the most cases a slight degree of mydriasis. The movement of the nictitating membranes and nystagmus were also observed. 3) The stimulation of the intermediate principal nucleus of amygdala proper (T of Völsch prepared a causative also to the same phenomena, but owing to lesions in the neighboring nuclei, the results remained far from being eviding. Still, a small anterior part of nucleus T' seemed to stand in connection with pupillary constriction. 4) Functional bearing of the periamygdaloid cortex upon the pupillary dilatation was to be said quite weak, likely concerned with periamygdaloid area Pam2 of Rose. Unlike tremor of the eyelids which came out most remarkably and more frequently, nystagmus appeared upon periamygdaloid stimulation only in three cases out of 10 experiments and was of large amplitude, its quick component directed toward the operated side and making a good contrast to the excitatory case observable in cases of the nucleus T stimulation. The movement of eyes was not exactly recognizable. The nictitating membranes were protruded in about half of the cases, presumably to be concerned with fuxction of Pam1 of Rose. 5) Stimulation of Walker's ares 13 aroused a moderate till remarkable pupillary dilatation. The neuronal relationship of this area was to consider as definitely different from that of amygdala. It should be added that Brodmann's area 53 showed also dilatatory effect 6) Removal of the cervical sympathetic ganglion worked toward diminution of the dilatatory effect of amygdala. 8) The neuronal relationship of the dilatatory effect of amygdala was attacked through series of sectioning experiments and resulted in proving that the fiber path passed through the fibers correspondent to the M. V. and M. D. of Fukuchi in Ungulata.