Figure 7. Lesions of NAc GABAergic neurons do not impair signaled avoidance learning or performance. A, Coronal NeuroTrace (green) stained section of a Vgat-Cre mouse injected with a Cre-dependent AAV-dtA in the NAc to kill GABAergic neurons. We counted the number of cells in the NAc in controls and lesion mice. There was a significant reduction in the number of NAc neurons in the lesion mice. B, Behavioral performance during learning of AA1, followed by AA2 and AA3 procedures showing the percentage of active avoids (top), avoid latency (middle), and ITCs (bottom) for control and lesion mice. The AA3 procedure shows CS1 and CS2 trials for the same sessions. Active avoids during AA3-CS2 trials are errors, as the mice must passively avoid during CS2. Lesion mice tended to have shorter avoid latencies, but as is usual both control and lesion mice shifted their avoid latencies longer during AA2 compared with AA1 (n = 9 lesion mice; n = 6 control mice). C, Movement (speed) from the CS onset (left) and from avoid occurrence (right) during AA1 and AA2 procedures for control and lesion mice. The lesion had little effect on movement other than the tendency to shift avoid movement sooner. However, the overall avoid speed measured from response occurrence was not faster in lesion mice. As typically observed in controls, lesion mice avoided faster during AA2 compared with AA1. D, Same as C for AA3. E, Population measures of orienting, avoidance, and escape responses from the CS onset (left) and from response occurrence (right) for overall movement. F, Bilateral electrolytic lesions targeting the NAc. G, Effect of bilateral electrolytic NAc lesions on behavioral performance in a RM design. The plot shows the percentage of active avoids (filled black circles), avoid latency (open orange squares), and ITCs (cyan bars). Mice were trained in AA1 prior to the lesion and then placed back in AA1, followed by AA2 and AA3. The main effect of the lesion was to increase the number of ITCs during AA1, with little negative effect on active avoids. During AA2, lesion mice normally abolished their ITCs, which are punished, and shifted avoid latencies longer with little effect on avoidance performance. During AA3, lesion mice also performed AA3 normally, actively avoiding during CS1 and passively avoiding during CS2 (n = 9 lesion mice).