Abstract
The amygdala has been implicated in either mediating or modulating affective memory formation. To evaluate these two views, female Long-Evan rats received lesions of the amygdala central nucleus (CEA) or basolateral complex (BLC) and were trained on the step-through and step-down inhibitory avoidance tasks. Both responses learned under an inescapable procedure were impaired by CEA or BLC lesions, whereas those learned under an escapable procedure were impaired only by BLC lesions, suggesting that learning the two different tasks relied on the same amygdala circuit, but deploying different coping strategies engaged different circuits. To further address the issue, CEA and BLC ensemble activities were recorded in retention tests of an escapable step-down task and an inescapable step-through task. For both tasks, repeated exposure to a training apparatus caused habituation of neuronal firing, and training led to increased firing activities in both the CEA and BLC. Some neurons were highly reactive in one task, and others highly reactive in both. These data suggest that CEA and BLC neurons may be involved in processing both specific and general information inherent in inhibitory avoidance tasks and that the amygdala may play both modulating and mediating roles for different aspects of affective memory.