i68 



PHYSIOLOGICAL TRIGGERS 



cortex and fornix, without blocking the neuroendocrine reflex. Similarly in- 

 eflfective have been relatively large lesions in the septum, lateral amygdaloid 



L C I 



V MH 



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 ■ Nembutol — • i"^^ 



C. D E 



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Fig. 3. Effect of histamine-Nembutal on EEG of rabbit brain. ^4, control run under ether. 

 5, 10 minutes after 0.5 mg histamine intraventricularly and more ether. Nembutal dosage, 

 6 mg/kg, i.v. C, 10 minutes after B, 20 minutes after histamine. D, 10 minutes after C, 

 2 minutes after AgNOa on orbitofrontai cortex, '2 minute before cutting ofactory bulb, E, ^^ 

 minute after transecting left ofactory bulb. (From Af>i. J. Physiol. 180: 37, 1955.) 



Abbreviations used in this and subsequent records and diagrams: AC, Anterior commis- 

 sure; AMYG, amygdaloid nuclei; C, caudate nucleus; CC, corpus callosum; EKG, electro- 

 cardiogram; FC, frontal cortex; IC, internal capsule; LC, limbic cortex; LH.\, lateral hy- 

 pothalamic area; LPO, lateral preoptic area; MFB, medial forebrain bundle; ML, lateral 

 mammillary nucleus; MM, medial mammillary nucleus; MP, mammillary peduncle; MPO, 

 medial preoptic area; OB, olfactory bulb; OCH, optic chiasma; PO, preoptic area; PUT, 

 putamen; SO, supraoptic nucleus; SP, septum; VHPC, ventral hippocampus; VMH, ventro- 

 medial hypothalamic nucleus. 



nuclei, thalamus and dorsal hypothalamus. Large anterior hypothalamic and 

 preoptic lesions were usually fatal, probably due to an upset thermoregulatory 

 mechanism, before they could be tested by mating. Five hypothalamic lesions 



