Interactions between the Central Nervous System and Hormones 81 



and Derbyshire (15). Their findings have been confirmed repeatedly during the 

 past 20 years, and a basal tuberal area especially sensitive to this type of 

 stimulation has been outlined by Saul and Sawyer (16, 17) (Fig. 1). Localized 

 electrolytic lesions in the middle of this area block copulation-induced 

 ovulation in the rabbit with or without causing ovarian atrophy (18,19). 

 An almost identical site, extending from ventromedial nuclei to mammillary 

 bodies, has been delineated in the cat hypothalamus by Robison and Sawyer 



OLFACTORY, 

 BULB 



LAT 

 OLFACTORY 

 STRIA 



AMYGDALA 



Fig. 2. Relationships of rhinencephalic structures and sites of lesions. A, transection of 

 olfactory tracts or removal of bulbs; B, transection of fornix; C, septal lesion; D, amygdaloid 

 lesion. MB, mammillary body; MFB, medial forebrain bundle; PIT, hypophysis. From 



Sawyer (19). 



(20, 17) (Fig. 1) in which stimulation during estrus induces ovulation and 

 lesions cause ovarian atrophy. Differential regions have been outlined which 

 appear to control reproductive behavior in the two species (Fig. 1). Stimu- 

 lation of these areas does not induce ovulation, and lesions do not lead to 

 ovarian atrophy but do produce a condition of permanent anestrus which 

 cannot be reversed by exogenous estrogen; ovulation can still be induced 

 by direct stimulation of the gonadotropic area. 



Projecting into the hypothalamus are numerous fiber tracts from the 

 rhinencephalon or limbic lobe, the part of the brain which Papez (21) proposed 

 as the anatomical substrate of emotion. These pathways include the medial 

 forebrain bundle from olfactory and other rostral areas, the fornix from the 

 hippocampus and the stria terminalis from the amygdala. The projections 

 are now considered two-way circuits (22), but evidence of their involvement 



