Effects of chronic ethanol consumption associated or not with experimental anterior thalamic lesions on spontaneous...

Previous studies from our team have shown that a 12 month ethanol administration induced deficits in a sequential alternation task, whereas a 6 month treatment had no effects. We have already shown that the 12 month treatment induced deficits both in diencephalic and hippocampal structures, whereas the 6 month treatment damaged only the mammillary bodies. Thus, the question remained whether or not increasing selectively the diencephalic damage by lesioning the anterior thalamic nuclei would disrupt sequential alternation in 6 month ethanol-treated mice. Results indicate that alcohol-treated mice exhibiting experimental lesions into the anterior thalamus were significantly impaired in the sequential task as compared to both controls or 6 month ethanol-treated mice. In contrast, anterior thalamic lesions in normal (no alcohol treatment) subjects induced no deficits. The relative contribution of the hippocampo-mammillo-thalamic circuitry in sequential alternation is discussed.