Davis et al. (1982) proposed a primary acoustic startle circuit in rats consisting of the auditory nerve, posteroventral cochlear nucleus, an area near the ventrolateral lemniscus (VLL), nucleus reticularis pontis caudalis (PnC), and spinal motoneurons. Using fiber-sparing lesions, the present study reevaluated these and other structures together with the role of neurons embedded in the auditor...

Considerable evidence suggests that the lateral (LA) and basal (BA) nuclei of the amygdala are sites of plasticity and storage of emotional memory. Recent arguments, however, have seriously challenged this view, suggesting that the effects of amygdala lesions are attributable to interference with performance of fear behavior and not learning and memory. One way to address this controversy is to...

Previous studies have established the usefulness of endothelin-1 (ET-1) for the production of focal cerebral ischemia. The present study assessed the behavioral effects of focal ET-1-induced lesions of the sensorimotor cortex (SMC) in adult rats as well as cellular and structural changes in the contralateral homotopic motor cortex at early (2 days) and later (14 days) post-lesion time points. E...

It has been suggested that increased sympathetic activity and arterial chemoreceptors are important for the high blood pressure in spontaneously hypertensive rats (SHR). Electrolytic lesions of the commissural nucleus of the solitary tract (commNTS) abolish (1) the cardiovascular responses to chemoreflex activation with potassium cyanide (KCN) in normotensive rats and (2) the hypertension that ...

Three groups of rats were trained to perform a differential discrimination task in a 2-tone operant conditioning paradigm. One group received electrolytic lesions of the medial septal nuclei, another received electrolytic or knife cut lesions of the entorhinal cortex. These groups were compared with a normal control group. Recordings of granule cells in the fascia dentata were obtained in all a...

Social agonistic behaviour of intact male rats is strongly reduced by the experience of defeat by a dominant male conspecific. Small electrolytic lesions in the corticomedial amygdala strongly affected this behavioural change due to defeat. No effects of the lesions were observed before and during the defeat. Some learning is still possible in corticomedial amygdala lesioned animals. A comparis...

The role of the ventromedial nuclei of the hypothalamus (VMN) in food behavior was studied in adult male rats, allocated in 3 groups: control, sham and lesioned. Electrolytic lesions were induced stereotaxically (1.2 mA, 15 sec). Results revealed a significant decrease (p<O.05) in body weight (BW) and food intake (FI) in the order of lesioned <sham <control during the fIrst week. However, ...

Both monoaminergic and cholinergic afferent projections to the neocortex putatively modulate cortical morphogenesis and plasticity. Previously we showed that neonatal electrolytic lesions of the cholinergic nucleus basalis magnocellularis (nBM) projections to the neocortex result in significant decreases of cortical layer width that correlate with cognitive alterations. Such electrolytic lesion...

A large body of literature implicates the amygdala in Pavlovian fear conditioning. In this study, we examined the contribution of individual amygdaloid nuclei to contextual and auditory fear conditioning in rats. Prior to fear conditioning, rats received a large electrolytic lesion of the amygdala in one hemisphere, and a nucleus-specific neurotoxic lesion in the contralateral hemisphere. Neuro...