AMYGDALA 



1407 



place during stimulation (41, 61, 129, 160, 198). 

 This suggests that stimulation of the amya;dala may 

 easily interfere with memory-recording mechanisms 

 and processes integrating conscious perception. 

 E\idence that this is also tlie case in animals, although 

 the\' may display the pantomime of attentive be- 

 havior, is given by Gastaut and his collaborators (72, 

 82, 88, 186, 190J. An interesting observation is that 

 lack of awareness in these animals is sometimes re- 

 stricted to stimuli applied to the side of stimulation 

 from which the head is turned due to the contraversive 

 effect of stimulation less (88). 



Topographical Representation of Function in Amygdala 



Two groups of workers have tried to correlate 

 specific amygdaloid stimulation responses with par- 

 ticular subdivisions of the amygdala. Kaada et al. 

 (135) state that the autonomic and immediate somato- 

 motor responses are obtained by stimulating the 

 anteriomesial part, comprising the corticomedial 

 complex and the medial portion of the basal nucleus. 

 Stimulation of the lateral amygdala, comprising the 

 lateral part of the basal nucleus and the lateral nu- 

 cleus, is said to elicit behavioral responses such as 

 attention, fear and rage and also responses suggestive 

 of some subjective sensory experience. There was, 

 however, a striking accumulation of autonomic, 

 somatomotor and behavioral types of responses in 



the basal nucleus, the densitv of responsi\e points 

 falling off rather rapidly both in the medial and 

 lateral direction. The work of Koikegami and his 

 collaborators (146-152) also shows that most of the 

 responses were obtained from the basal nucleus. 

 According to the results of Kaada el al. (133) only a 

 small proportion of the autonomic and somato- 

 motor responses were obtained from points clearly 

 within the corticomedial subdivision. It may there- 

 fore not he significant that no behavioral responses 

 were obtained from the corticomedial subdivision 

 in this experimental series. 



Koikegami and his collaborators (146-152) attrib- 

 ute to the medial portion of the basal nucleus pre- 

 dominantly sympathetic effects, and consider the 

 lateral portion of the basal nucleus and the cortical 

 and medial nuclei as activating parasympathetic 

 functions. 



Other authors have been more impressed by the 

 wide range of overlap of points yielding a rich variety 

 of responses and felt that no topographical organiza- 

 tion of functions could be deduced from stimulation 

 results (fig. 7) (i 1-15, 82, 172, 190). However, despite 

 this hesitancy to attribute certain functions to certain 

 definite amygdaloid subdivisions, many authors in- 

 dicate the locations from which they obtained par- 

 ticular stimulation effects. A comparison of all these 

 findings, as shown in table i , fails however to reveal 

 any consistency in localization of the various amygda- 



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