PSYCHOSOMATICS 



'733 



fig. I. Schematic drawing, placing 

 emphasis on the medial forebrain 

 bundle (M.F.B.) as a major line of 

 communication between the limbic 

 lobe and the hypothalamus and mid- 

 brain. The concentric rings of archi- 

 cortex and mesocortex of the limbic 

 lobe are shown, respectively, in dark 

 and light stipple. In this diagram only 

 the ascending pathways of the M.F.B. 

 are indicated, and attention is focused 

 on the divergence of two streams of 

 fibers to the ( / ) amygdala and (2) septum 

 where there are confluences with fibers 

 from the olfactory apparatus. Limbic 

 structures associated with the amygdala 

 and septum are allegedly concerned, 

 respectively, with self-preservation and 

 preservation of the species. .17-, 

 anterior thalamic nuclei, C.G., central 

 gray of midbrain, D.B., diagonal band 

 of Broca; G., ventral and dorsal teg- 

 mental nucleus of Gudden; HYP., 

 hypothalamus; L.M.A., limbic midbrain 

 area of Nauta; .1/., mammillary body; 

 PIT., pituitary; S.C., superior colliculus. 

 [From MacLean (39).] 



CINGULATE GYRUS 



CNGULUM BUNDLE 



of structures making up the limbic system consti- 

 tuted a "harmonious mechanism which ma\ elabo- 

 rate the functions of central emotion, as well as par- 

 ticipate in emotional expression." The kernel of this 

 idea can be found in the writings of Herrick and he- 

 fore him in those of Elliot Smith (J"")). In [949 the 

 present author enlarged on the Papez thesis and 

 reviewed the interim developments which tended 

 to support the general validity of his them \ (33). Of 

 these the following were particularly notable: a) the 

 findings of Kliiver & Bucy that in wild monkeys 

 bitemporal lobectomy, provided it included the 

 limbic structures, resulted in apparent tameness, in a 

 compulsive type of oral behavior and in bizarre sexual 

 activity (29); />) the work of Spiegel et al. (63) and of 

 Bard & Mountcastle (3), concluding that ablations of 

 the amygdala in carnivora led to manifestations of 

 rage; c) the reports of Smith (62) and of Ward (67) 

 that bilateral removal of the anterior cingulate por- 

 tion of the limbic lobe in monkeys was followed by 

 loss of fear and other changes in emotional behavior; 

 d) the observations of several workers that autonomic 

 manifestations commonly seen to accompany emo- 

 tional states could be elicited by electrical stimulation 

 from the entire rostral part of the limbic cortex in 

 both man and animal; and e) electroencephalographic 

 findings that in psychomotor epilepsy, in which there 



is a wide variety of emotional and viscerosomatic 

 manifestations, the epileptogenic focus is frequently 

 found in or near limbic structures at the base of the 

 brain. The majority of these findings have been con- 

 firmed, but their is unresolved conflicting evidence in 

 regard to the ablation studies referred to under b ) and 



Further work has recently begun to suggest that 

 respective portions of the limbic system are pre- 

 dominantly concerned with emotionally determined 

 functions pertaining to the preservation of the self or 

 of the species. 



Self-preservation. The frontotcmporal portion of the 

 limbic s\stem appears to mediate functions that pri- 

 marily promote the preservation of the self (cf. 34, 35). 

 This region embraces the interrelated mesocortex 

 of the orbital, insular, temporal polar and pyriform 

 areas, all of which have likewise been shown neuro- 

 nographically to be connected with the amvgdala 

 and to the archicortex in the part of the hippocampus 

 lying proximal to the amygdala (54). This group of 

 structures is played upon by a confluence of afferents 

 from the lateral olfactory tract and ascending path- 

 ways from the brain stem (cf. fig. 1). 



An analysis of stimulation studies in unrestrained 

 and waking animals reveals that the responses ob- 

 tained from intermixed points in the frontotemporal 



