BASOLATERAL AMYGDALA LESIONS BLOCK GLUCOCORTICOID-INDUCED MODULATION OF MEMORY FOR SPATIAL-LEARNING

This study examined the role of the amygdala in mediating the effects of glucocorticoids on spatial memory in rats. Adrenalectomy (ADX) indu ced 4-5 days prior to training impaired memory in a water-maze spatial task. This effect was reversed by a posttraining injection of dexamet hasone (0.3 mg/kg sc) but not by corticosterone (0.3 mg/kg). Lesions o f the basolateral (BLA), but not the central (CEA) or the medial (MEA) , amygdala blocked the effects of ADX and dexamethasone. ADX also impa ired acquisition. CEA, MEA, and BLA lesions blocked the ADX effect on acquisition. In adrenally intact rats, intracerebroventricular posttra ining injections of a specific glucocorticoid receptor (GR or Type-II) antagonist impaired retention, and BLA lesions blocked the effect of the GR antagonist. These finding provide evidence that the BLA is invo lved in mediating glucocorticoid influences on learning and memory.