PSYCHOSOMATICS 



'73 1 



most crucial to a state of wakefulness, and hence 

 awareness, is contained in the reticulum of the mid- 

 brain which is, of course, possessed by the decerebrate 

 animal (43). In regard to the question of emotion 

 only a few observations come to mind, and these per- 

 tain to intact preparations. It has been observed that 

 cats which upon chemical or threshold electrical stim- 

 ulation of the hypothalamus show angry manifesta- 

 tions will nevertheless continue lapping milk (46), or 

 will be submissive to petting and stop to purr and lick 

 the examiner's face between growls (36). As Masser- 

 man (46) emphasized, such paradoxical behavior 

 suggests that the animal, although expressing anger, 

 does not 'feel' angry. Using conditioning methods he 

 attempted to obtain information that would allow 

 further inferences about this matter. In brief, he found 

 that cats could not become conditioned to the 

 prospect of receiving electrical stimulation of the 

 hypothalamus with intensities that were just sufficient 

 to elicit signs of angry behavior. He believed these 

 findings supported his original assumption, and he 

 concluded that whereas the hypothalamus serves as 

 an integrator of emotional expression, it is not con- 

 cerned in the experience of emotion. 



With this background in regard to the basic, but 

 limited, contribution of the neural chassis to emo- 

 tional processes, we turn now to an analysis of the 

 mechanisms of the cerebral 'driver' embodied in the 

 forebrain which evokes forward of the anterior neuro- 

 pore. This will entail a consideration of the basal 

 ganglia and the cerebral cortex, and their dependent 

 relationship to the dicncephalon and other structures 

 of the brain stem. 



Basal Ganglia 



The basal ganglia of the forebrain are made up of 

 a complex of structures comprising the striatum 

 (putamen and caudate) and the globus pallidus. 

 Johnston (27) gives convincing reasons for not includ- 

 ing the amygdala, often considered as 'archistriatum,' 

 as one of the basal ganglia. Edinger (15) referred to 

 the corpus striatum as a "mighty part of the brain 

 which must be of enormous significance; otherwise it 

 would not be present from fishes on upwards. . . ." 

 This portion of the basal ganglia has continued since 

 Edinger's time to be one of the most enigmatic struc- 

 tures of the brain. Considering its size and central 

 location, one wonders if there can be any significant 

 strides in the knowledge of cerebral physiology until 

 more is known about its function. (The present status 

 is presented in Chapter XXXV of this Handbook.) 



Most of the clues about its role in behavior have been 

 given by clinical observations. On the basis of deficits 

 resulting from lesions, it has been inferred that it is 

 essentially a motor apparatus concerned with coor- 

 dinating postural, locomotor and visceral adjustments 

 invoked in all forms of behavior, including, of course, 

 emotional expression. There are intimations from 

 Rogers' ablation studies in pigeons (56) that this 

 purely 'motor" interpretation represents too restricted 

 a view of its activities. He found that pigeons de- 

 prived of the corresponding part of the brain could 

 neither retain nor acquire the ability to place in 

 proper sequence their otherwise retained patterns of 

 behavior making up the rituals of mating and nesting 

 behavior. This would indicate that the striatum 

 plays an important role in learning and becomes a 

 reservoir of learned performance. Except for an ap- 

 parent loss of fear, Rogers could discern no deficits 

 that could be attributed to the deprivation of cortex 

 alone. In contrast to the bird, Bard & Rioch (4) con- 

 cluded from an analysis of their ablation studies on 

 cats that, in the absence of neocortex and hippo- 

 campus, "the striatum plays a very minor role in 

 behavior" and that there is no evidence that in itself 

 it represents .1 center' for the elaboration of emo- 

 tional activity. 



(.111 hull ('.mil \ 



On the basis of phylogenetic and cytoarchitectural 

 considerations the cerebral cortex can be subdivided 

 into three general types. These may be designated as 

 archicortex, mesocortex and neocortex. The archi- 

 cortex and the greater part of the mesocortex are 

 contained in the great limbic lobe which lies medially 

 in the cerebrum and surrounds the brain stem. In 

 the evolution of mammals, the neocortex undergoes 

 an exuberant growth with the result that in higher 

 forms it covers over and obscures the 'old' cortex. 



neocortex. The integrity of function of the neocortex 

 depends on its connections with the neothalamus. 

 There is no evidence that the cortex posterior to the 

 central fissure is specifically concerned with emo- 

 tional behavior. Rather, it appears to elaborate on 

 the sensory data it receives in such a way as to derive 

 information required for behavior that may be suc- 

 cinctly described as intellectual in character. In 

 man, it participates in the elaboration of language. 



Forward of the central fissure a wide variety of 

 autonomic effects have been elicited upon stimula- 

 tion of the so-called 'motor' areas. Observations 



