Noradrenergic activation of the basolateral amygdala modulates consolidation of object recognition memory.

Noradrenergic activation of the basolateral complex of the amygdala (BLA) modulates the consolidation of memory for many kinds of highly emotionally arousing training tasks. The present experiments investigated whether posttraining noradrenergic activation of the BLA is sufficient to enable memory consolidation of a low-arousing training experience. Sprague-Dawley rats received intra-BLA infusions of norepinephrine, the beta-adrenoceptor antagonist propranolol or saline immediately after either 3 or 10 min of object recognition training. Saline-infused controls exhibited poor 24-h retention when given 3 min of object recognition training and good retention when given 10 min of training. Norepinephrine administered after 3 min of object recognition training produced dose-dependent enhancement of 24-h object recognition memory whereas propranolol administered after 10 min of training produced dose-dependent impairment of memory. These findings provide evidence that posttraining noradrenergic activation of the BLA enhances memory of a low-arousing training experience that would otherwise not induce long-term memory. Thus, regardless of the degree of emotional arousal induced by an experience, noradrenergic activation of the BLA after the experience ensures that it will be better remembered.