In seven mongrel dogs the syndrome of depression was evoked by bilateral electrolytic lesions in lateral hypothalamus and/or dorsomedial amygdala. The effects of tricyclic antidepressants on general mood, spinal reflexes recorded by electromyographic method, and head rate were tested. The reactivity to most external stimuli was increased and general depression was slightly reduced.

The mating behavior of a group of male golden hamsters was observed before and after bilateral electrolytic lesions or knife cuts interrupting the stria terminalis (ST). Whereas males with bilateral lesions of the medial nucleus of the amygdala had previously been observed to stop mating, a majority of hamsters with bilateral ST destruction, whether by electrolytic lesions or knife cuts, contin...

The dorsal (DH) and ventral (VH) subregions of the hippocampus are involved in contextual fear conditioning. However, it is still unknown whether these two brain areas also play a role in defensive behavior induced by electrical stimulation of the dorsal periaqueductal gray (dPAG). In the present study, rats were implanted with electrodes into the dPAG to determine freezing and escape response ...

Electrolytic lesions were placed in the hypothalamus of two-day-old female rats. Destruction of the mediobasal part of the preoptic area resulted in persistent vaginal estrus starting on the day of vaginal opening, while lesions placed laterally in the preoptic-anterior hypothalamic area did not interfere with normal cycles. Therefore, the mediobasal hypothalamus is capable of undergoing matura...

Two groups of rats--1 with electrolytic lesions of the hippocampus and 1 consisting of sham-operated controls--received flavor-aversion conditioning with 2 flavors. All subjects had received prior nonreinforced exposure to Flavor A. Latent inhibition was apparent in slower acquisition of the aversion to Flavor A than to Flavor B. Hippocampal lesions had no effect on acquisition to the nonpreexp...

Clinical and recent imaging reports demonstrate the involvement of various cerebral prefrontal areas in the processing of pain. This has received further confirmation from animal experimentation showing an alteration of the threshold of acute nociceptive reflexes by various manipulations in the orbito-frontal cortical areas. The present study investigates the possible involvement of this area i...

Restricted electrolytic lesions of the lateral hypothalamus (LH) evoke sleeplessness in the rat. The present study was aimed to analyze a possible anatomical substrate of the LH hyposomnia within the hypothalamus. In a group of electrolytically lesioned LH rats the intensity of sleep disturbances, assessed on the basis of EEG records from the neocortex and the hippocampus, was confronted with t...

The goal of this work was to test the involvement of the central nucleus and basolateral complex of the amygdala in fear conditioning, using auditory and visual conditioned stimuli (CSs). The acoustic startle reflex in rats was used as the behavioral index of conditioning because startle is reliably enhanced in the presence of a conditioned stimulus (CS) previously paired with a footshock. Init...

Specific destruction of at least 90% of the noradrenergic neurons in the preoptic/anterior hypothalamic region (PO/AH) by local injection of 9-hyroxydopamine (6-HDA) did not disrupt thermoregulation by rats either in the heat or the cold. Examination of the multiple effector mechanisms suggested that thermal balance was maintained in a normal fashion, and that compensatory adjustments did not c...

The role of the lower brain stem in controlling preovulatory gonadotropin surges was investigated in female rats under acute experimental conditions. Electrolytic lesions or diethyldithiocarbamate implantations in the ventrolateral part of the medulla oblongata (VLMO), which were carried out at 1100-1330 h on the day of proestrus, resulted in a blockade of the preovulatory surges of LH, FSH and...