EMOTIONAL BEHAVIOR 



'54' 



analyses of affective processes. Not only has the 

 conditioned behavior of the individual animal with 

 limbic system involvement begun to come under 

 careful scrutiny in specifically controlled testing 

 situations, but even the integration of social be- 

 havior and its dependence upon these neural systems 

 has now been explored. Rosvold el al. (321) observed 

 that the effects of amydalectomy in eight male 

 Rhesus monkeys generally changed their hierarchical 

 position in a group-cage situation from dominant 

 to submissive, even though they appeared somewhat 

 more 'aggressive' when in individual cages. Cer- 

 tainly, the results of these experiments would seem 

 to suggest that the postsurgical social environment 

 and the length of time preoperative relationships 

 have existed can be as important a consideration as 

 differences in the extent and location of the lesion in 

 evaluating the consequences of limbic system ablations 

 for emotional behavior. And indeed, clinical reports 

 of observations following temporal lobe and amyg- 

 daloid lesions in man by Terzian & Ore (363) and 

 Sawa et al. (326) have emphasized this same diminu- 

 tion of 'social aggressiveness.' Gastaut and colleague 

 (144) have also pointed out that discharging lesions 

 in these limbic system structures, as seen in psycho- 

 motor epilepsy, apparently produce a lowered 

 'rage' threshold since these patients frequently show 

 violent temper outbursts in social situations. Ii ma) 

 also be significant that Gastaut & Collomb (142) 

 have observed a decrease in sexual behavior in these 

 patients with irritative lesions of the temporal lobe- 

 amygdala region, while Gastaut & Mileto (143) 

 have further elaborated upon the disturbances in 

 sexual behavior which follow involvement of the 

 hippocampus in both human and animal cases of 

 rabies. 



Many physiological studies (4, <), (>8, 77, 78, 132, 

 141, 202-204, 221-226, 257, 260, 307, 311. 33 6 > 380 

 in both animals and man, using chemical and elec- 

 trical stimulation as well as electrical recording 

 methods, have also demonstrated limbic system in- 

 volvement in a wide variety of somatic and auto- 

 nomic phenomena closely related to the broad range 

 of behavioral activities conventionally associated with 

 emotional expression. Significantly, it has been 

 difficult to discern any clear-cut topographical or- 

 ganization for specific behavioral components, 

 even though the observations of Kaada et al. (203) 

 would seem to suggest that such delineation may be 

 possible. For the most part, however, the striking 

 features of such correlative data would seem to be 

 the extensive overlap of all sorts of behavioral re- 



sponses in their representation at this limbic system 

 level (203, 221-226), and the remarkably broad 

 spectrum of psychological activities in which these 

 structures can be presumed to participate (132, 141, 

 202, 257, 311). Heath and his collaborators (169, 

 238) have even recently proposed extensive involve- 

 ment of these specific neural systems in the elabora- 

 tion of 'thought' and 'psychological awareness.' 

 The intimate relationship of these limbic structures 

 (particularly the amygdala) to the mechanisms of 

 neuroendocrine integration has been convincinglv 

 demonstrated by both stimulation and ablation 

 studies (166, 190, 223, 225, 267, 308, 327, 331-333). 

 Finally, electrophysiological methods have con- 

 tinued to define the characteristic functional inter- 

 relationships within the limbic svsiein and subcor- 

 tical regions basically involved in the elaboration of 

 emotional behavior (68, Il8, 119, [53— 155, 157, 

 241, 242). Of particular importance in this respect 

 would seem to be the extensive studies of Macl.ean 

 and his collaborators (2 , 260), and of Gloor (153- 

 [55), carefully delineating the limbic system role in 



affective processes. 



Imi with this host of clinical and experimental 

 observations, and the rapidly accumulating body 

 of anatomical, physiological and psychological in- 

 formation, however, no completely satisfactory in- 

 tegration of the limbic system with the neeessarilv 

 broad range of central neural participants in emo- 

 tional behavior has .is vei emerged. There never has 

 been ,mv shortage of speculative efforts assigning 

 specific functional roles to the various components 

 of this anatomical complex, and a significant thread 

 of similarity is indeed discernible among the many 

 neurological hypotheses which have characterized 

 the multidisciplinary theorizing in this area. Almost 

 30 years ago, for example, Herrick ( 1 7 ~, ) , on a com- 

 parative an.itomie.il basis, suggested that the limbic 

 system mav serve as .1 nonspecific activator for all 

 cortical activities, influencing "the internal appara- 

 tus of general bodily attitude, disposition, and affec- 

 tive tone." Even Kleist's (215) speculations of the 

 same era about the 'inner brain,' as he referred to the 

 more medial aspects of the hemisphere, can be 

 seen to emphasize the fact that these limbic struc- 

 tures were not only basic for 'emotional behavior,' 

 'attitudes' and 'drives,' but were also instrumental 

 in correlating 'visceral receptions' from the oral, 

 anal and genital regions, as well as the intestines, 

 thus subserving functions related to the search for 

 food and sexual objects. And clinical observations of 

 human patients with limbic system involvement led 



