K. LISSAK AND E. ENDROCZI 



301 



behavie:)ur. Stimulation of the hippocampus in various laboratory animals 

 diminished the resting corticoid level in the blood of the adrenal vein 

 and prevented the adrenocortical hyperactivity elicited by humoral or 

 neurotropic stimuli (Endroczi and Lissak, 1959). 



Except for a slight initial orientation-reaction no changes were observed 

 during hippocampal stimulation. This is in agreement with die findings of 

 other authors (Pentield and Jasper, 1953; Akert and Andy, 1953). 



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^5 



t 



'i ^ K' f6 20 z'i li jz 36 'ji "vr 



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CpdF 



CpcJb 



Fig. 7 

 rhc mrtucncc iif hippocampal stinuilation (through 

 1 5 minutes) on the corticoid content of blood in the 

 adrenal vein of cats. Marked lowering of corticoid 

 level v^'as observed. 



It may be asked in what pathways these neuroendocrine processes and 

 behavioural changes are regulated by the archicortex and archistriatum. 

 Without going into the details of relevant literary data we suppose that 

 the chief ascending afferent pathways of archicortex and archistriatum 

 pass through the septum and c^riginate from the tegmental nuclei. Electro- 

 coagulation destruction of the subcallosal area in the septum resulted in a 

 spectrum of corticoids similar to that found after repeated stmiulation of 

 the medial part of the pyriform-amygdale complex. Other lesions of the 

 septum touched only the subcallosal grey matter and elicited an opposing 

 effect. In these animals a diminished content of corticoids in the blood of 

 the adrenal vein was found 2-3 weeks after the operation. With regard to 

 the varied localization of these lesions, we suppose it must be due to the 

 chronic irritation of afferent connections related to the hippocampus. 

 Complete destruction of these afferent pathways can abolish the hippo- 

 campal inhibitory influence on the stress mechanism and the control of 



