•73 2 



II WIU'.i ll iK i H IIIV SIl il i ii. \ 



NEUROPHYSIOLOGY III 



made on animals and man in the absence of anes- 

 thesia have given no indication that these responses 

 are associated with emotion. It has been suggested 

 that they reflect the cortical integration of supporting 

 autonomic adjustments with existing or anticipated 

 movements of the skeletal musculature. The second 

 possibility has relevance to functions of the neigh- 

 boring prefrontal cortex and its role in emotion 

 which will now be considered. 



In !<)■;(> I'm hi in .iiul Jacobsen reported on the effects 

 of excising in two chimpanzees the tips of the frontal 

 lobes containing the prefrontal cortex. Their observa- 

 tion that this operation had the effect of alleviating 

 the symptoms of an experimental neurosis in the 

 animal called Becky led Moniz to introduce frontal 

 lobotomy as a treatment for mental illness (20). This 

 once popular procedure has provided a wealth of 

 clinical material pertaining to the functions of the 

 frontal lobes. From an analysis of the data it appears 

 that the prefrontal cortex is a neural elaboration that 

 is primarily concerned with anticipation and planning 

 .in ii applies to both the self and the species. As far as 

 one is able to judge, the relief of emotional symptoms 

 following lobotomy is primarily attributable to the 

 alleviation of anxiety. As previously noted, anxiety is 

 an emotional state associated with alerting for and 

 anticipation of future events. It might be inferred 

 therefore that emotional guilt feelings are relieved by 

 lobotomy because there is no longer the anxiety that 

 attends anticipation of discovery and punishment for 

 asocial thoughts or acts; that intractable pain, al- 

 though still experienced, is alleviated because there is 

 no longer the anxiety associated with the anticipa- 

 tion of continued suffering. Similarly, the socially 

 unacceptable behavior which is so frequently seen 

 as one ill the undesirable effects of lobotomy might 

 be attributed to an individual's failure to anticipate 

 the consequences of giving expression to his immedi- 

 ate impulses. 



In line with the views of Cannon that were re- 

 ferred to in the historical section, it was the consensus 

 prior 10 M).;!) that the diencephalon was the pan of 



the brain thai elaborated the experience and expres- 

 sion of emotion. Except for its alleged capacity to 



arbitrate upon and inhibit the expression of emotion, 

 ii was believed thai the cerebral cortex did not par- 

 ticipate in emotional processes. The new findings in 

 regard to frontal lobotomy led to the assumption that 

 the prefrontal cortex was necessary for the experience 

 nf emotion. But a sole emphasis on the prefrontal 

 cortex in this regard was hardly justified in the lighl 

 nl the two following considerations, 0) Lashley has 



pointed out that "fundamental patterns of emotional 

 reaction and temperamental types seem to have 

 undergone little change in mammalian evolution. 

 The major changes are rather the result of the develop- 

 ment of intelligent foresight and the inhibition of ac- 

 tion in anticipation of more remote prospects" (31). 

 /)) The prefrontal area, in contrast to the phylogenet- 

 ically old cortex with which we are next to deal, 

 represents one of the cortical formations of the brain 

 that has undergone a very extensive degree of develop- 

 ment in the evolution of the mammal. 



THE PHYLOGENETICALLY OLD CORTEX. The phv lo- 



genetically old cortex comprises the archicortex and 

 the mesocortex. The archicortex and the greater part 

 of the mesocortex are contained in a large cerebral 

 convolution which Broca (10) in 1878 named the 

 great limbic lobe. The term limbic was used to indi- 

 cate that this lobe surrounds the brain stem. The 

 limbic lobe, as Broca pointed out, is found as a 

 common denominator in the brains of all mammals. 

 As shown schematically in figure 1, the archicortex 

 and mesocortex envelop the ring-like limbic lobe in 

 two concentric bands. The mesocortex, which forms 

 the outer band, makes up most of the superficial 

 cortex of the limbic lobe and extends somewhat be- 

 yond its boundaries as perilimbic cortex. In evolu- 

 tion, the inner band of archicortex becomes largely 

 buried through a process of folding; and in higher 

 forms, it undergoes so much displacement by the 

 corpus callosum that the bulk of it comes to lie in the 

 hippocampus in the inferomedial part of the temporal 

 lobe. 



Broca emphasized the close evolutionary relation- 

 ship between the limbic lobe and the olfactory ap- 

 paratus. This led some authors to refer to this lobe 

 as the rhinencephalon, believing it subserved only 

 olfactory functions. Many physiologists still refer to 

 11 as such. The term limbic has the advantage that it 

 is a short and descriptive term and, as Broca pointed 

 out, implies no theory iii regard to function. 



The nuclear structures associated with the limbic 

 cortex include the hypothalamus, septum, amygdala, 

 anterior and mid-line thalamic nuclei, the habenula, 

 and parts of the basal ganglia. Ii has become evident 

 thai the limbic cortex and its subcortical cell stations 

 comprise a functionally integrated system. In keeping 

 with Broca's terminology, thissytem may be appropri- 

 ately referred to as the limbic system (34). 



In i<).;7 in a paper called "A Proposed Mechanism 

 oi Emotion, 1 Papez 1 ,1 1 drew extensh ely from his own 

 research and the literature to show that a number 



