'734 



HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY III 



region fall principally into two categories. One cate- 

 gory includes responses of an alimentary nature such 

 as licking, chewing, retching, etc. In the other cate- 

 <_!Mi\ are responses that one associates with the ani- 

 mal's search for food and its struggle for survival. 

 These include sniffing, searching, and angry attack or 

 defense with appropriate vocalization. 



Patients who sufTcr from psychomotor epilepsy as a 

 consequence of epileptogenic foci in this region show 

 parallel manifestations during their seizures. At the 

 same time they have symptoms that lend insight into 

 the subjective functions of this region. In keeping 

 with the automatisms that appear, they commonly 

 experience during the aura alimentary symptoms and 

 vivid emotions. There may lie alimentary feelings of 

 thirst, hunger, nausea, etc. The emotional feelings 

 are characteristically self-protective in nature and 

 are therefore unpleasant. Such feelings as fear, terror, 

 dread or anger may be variously associated with a 

 sense of epigastric distress, suffocation, choking or a 

 racing heart. Sometimes there is an alternation of 

 contrasting ■feeling' states, e.g. fear and anger. This 

 suggests there may be a neuroanatomical substratum 

 for the reciprocal innervation of "feeling' states that 

 compares to the reciprocal innervation of muscles 



(36)- 



Bilateral ablations of the frontotemporal region in 

 animals appear to abolish a number of self-preserva- 

 tive functions related to eating and self-protection. 

 As shown by Pribram & Bagshaw I 53) in ail extension 

 of Kliiver & Bucy's classic studies, wild animals 

 appear to become tame and docile after such an 

 operation. They lose their sense of fear and will expose 

 themselves again and again to painful and harmful 

 situations. A monkey which ordinarily eats fruit will 

 eat raw meat or fish. Ii will put feces, or nuts and I mils 

 in its mouth and sometimes swallow them. In short 

 such an animal loses the ,ibilil\ to look after its self- 

 protection and to eat properly. 



I rom the foregoing findings one is led to infer that 

 the frontotemporal region is largely concerned with 

 sin\ i\ .il mechanisms involved in obtaining and assimi- 

 lating food. 



Curiouslv enough, animals with bilateral ablations 

 of the frontotemporal region, in addition to lameness 

 .mil docility, reveal exaggerated sexuality that is 

 often bizarre in nature. This was well illustrated by 

 the experiments "I Schreiner & Kiing (59) in which 

 the) removed pan of this region in cats. Male cats 

 would indiscriminately mount another male cat, .1 

 female dog, a female monkey or even a chicken. 



These findings suggest that there was a release, in the 

 Jacksonian sense, of other parts of the brain involved 

 in procreative functions. 



Preservation of the species. This leads to the con- 

 sideration of another group of related limbic struc- 

 tures that seems to be invoked in forms of behavior 

 which, taken together, might be interpreted as being 

 conducive to the preservation of the species rather than 

 the self. As will be indicated, continuing investigation 

 is beginning to suggest that a neural system involving 

 parts of the hippocampus, cingulate gyrus and sep- 

 tum are implicated in pleasure and grooming reac- 

 tions and in sexual manifestations. Long ago Ramon 

 \ ( '.i jal emphasized the close anatomical relationship 

 of these structures (55). As indicated in figure 1, the 

 septal region is a place of confluence for sensory data 

 coming by way of the medial olfactory tract and as- 

 cending from the brain stem. 



In the course of investigating the structures under 

 consideration the author's laboratory has employed 

 a method (37) that permits simultaneous electrical 

 or chemical stimulation of the brain and recording of 

 the electroencephalographic and behavioral changes 

 in unrestrained and waking animals. Chemical stimu- 

 lation has usually been carried out by depositing 

 microamounts of cholinergic drugs in crystalline form. 

 Most of the observations have been made on cats. In a 

 study focusing on an intermediate segment of the 

 hippocampus, enhanced pleasure and grooming reac- 

 tions occurred in association with certain chemically 

 induced and long-enduring electroencephalographic 

 changes. The reader must be referred to the original 

 papers for details (37, 38). Contrary to what is usually 

 the case, male cats would readily submit to genital 

 stimulation, and sustained penile erections could In- 

 induced. Occasionally one observed a spontaneous 

 partial erection. Similar sexu.il manifestations and 

 enhanced pleasure and grooming reactions ,11c also 

 seen following hippocampal after-discharges induced 

 b\ electrical stimulation. The rat likewise engages in 

 intensive self-giooming lor several minutes following 

 electricall) induced hippocampal after-discharges, and 

 here too one inav note the presence of penile erections. 

 The investigations on the septum and cingulate 

 gyrus were largelv carried out bv Trembly, Kim and 

 l.cickhart.' Enhanced pleasure and grooming reac- 

 tions were seen in association with chemical stimula- 

 tion of certain parts of the septum and following aflcr- 

 discharges induced bv electrical stimulation In the 



' I lieu as vet 1 in piil >listu-< I <>liM 1 vations .ire referred in in the 

 literature (36, 38). 



