Supplementary Figure 2: Examples of rapid task-adaptive changes in neuronal response timing, amplitude and selectivity.

Each row in this figure shows responses of separate, individual VPr neurons in three behavioral conditions: (i) pre-task passive or quiet listening, (ii) during behavioral performance of either the PT-D or the CLR-D discrimination tasks, (iii) post-task quiet listening. Blue shaded areas indicate the duration of Safe sounds; Red shaded areas show the duration of Warning sounds. Red vertical dashed lines indicate the duration of the behavioral response window. The responses of the two VPr neurons in A and B (in the PT-D task) change from relatively short onset (latency of 25–30 ms) and peak latency of 75 ms in the passive condition to a very different response pattern during behavior. As shown in the two middle panels, the initial onset response observed in the passive condition is nearly completely suppressed during behavior in both cells, and much longer latency responses emerge (the neuron in the top row has a new longer latency peak at 375 ms and the neuron in the second row has two new longer latency peaks at 175 and 525 ms in the active task condition). In both cells, the longer latency responses vanish again in the passive condition and the cells return to having one peak response at 75 ms in the post-passive condition. The responses of the two VPr neurons in C and D (in the CLR-D task) also illustrate behavioral state changes in timing (onset and duration), amplitude, and stimulus selectivity. During passive listening the cell in C responds to TORC onset and to both the Warning and Safe click trains. However, during behavior, the cell selectively responds only to the Warning click trains and stops responding to the TORC stimuli or to the Safe click trains. The pattern of responses to the Warning stimuli (fast click trains) also changes, now showing a buildup response during behavior. Similarly, the neuron in D responds to both click train rates during quiescent listening, but then, as in the cell above (C), it responds selectively to the Warning stimulus during behavior. What makes the neuron in D even more interesting, is that the response timing to the Warning stimulus, shifts from Warning stimulus to sound offset – marking the timing of the shock window. In both cells (C and D), responses return to the original pre-passive form in the post-passive condition.