The hypothalamus: Neural systems involved in feeding, irritability, aggression, and copulation in male rats.

In 3 experiments with a total of 58 male hooded rats, cuts of the ventral amygdalofugal pathway resulted in slight aphagia, and cuts anterior to the medial preoptic area resulted in transient hyposexuality. A unilateral posterior medial forebrain bundle (MFB) cut combined with a contralateral parasagittal cut resulted in severe hyposexuality if the parasagittal cut lay lateral to the anterior hypothalamic nucleus, and in irritability if the parasagittal cut lay lateral to the ventromedial hypothalamic nucleus. It is concluded that (a) the medial hypothalamic nuclei exert their effects on irritability and copulation through their lateral connections with those components of the MFB that descend on, or ascend from, the lower brain stem; and (b) the neural pathways mediating the consummatory aspects of feeding, irritability, aggression, and copulation are distinct. (58 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)