We then proceeded to the calcium imaging 30 min after the last session of the stay task to see whether the activity pattern was

the same as or different from that in the avoidance task. Even after fish learned the stay task, we continued to observe activation in the dorsal telencephalon. However, remarkably, the activated areas observed after the stay task appeared slightly, but significantly, different from that observed Vorinostat cost in the initial avoidance task. The activated area was extended in a lateral and posterior direction (Figure 5C). The observed activity pattern difference was not the consequence of repeating conditioning in 2 consecutive days, because fish that were trained by the avoidance task on the first day and then by the avoidance task again on the next day showed calcium activity patterns similar to those observed 24 hr after the three avoidance conditioning

sessions were given and were not repeated any more (Figure S5C). In order to examine whether the enlargement did not appear simply because of the passage of time, we gave the fish Enzalutamide manufacturer only cues without punishment on the next day of the initial avoidance task. Even after four sessions, the acquired avoidance behavior was not extinguished (Figure S5D3). Consistent with the behavioral result, the calcium activity pattern in these fish was relatively similar to but did not get larger than that observed at 24 hr after the avoidance conditioning, further supporting the idea that the enlarged calcium activity pattern for the stay

task is specific to the learned stay behavior (Figures S5D1 and S5D2). When the centers of the activated areas for individual fish were collectively plotted with respect to standardized STK38 anatomical landmarks of the telencephalon (see Experimental Procedures), the clusters of activity centers between the avoidance task- and stay task-trained groups demonstrated a significantly different spatial pattern (Figure 5D). Importantly, the distances from the average point for the avoidance task (Figure 5D, orange crosses) to each activity center for the stay task were significantly larger than those to each activity center for the avoidance task in both hemispheres (Figure 5E1). Likewise, the distances from the average point for the stay task (Figure 5D, green crosses) to each activity center for the avoidance task were significantly larger than those to each activity center for the stay task in both hemispheres (Figure 5E2). These analyses indicate that the patterns of clustered activity were significantly shifted between the avoidance and stay tasks. We compared the time sequence of stay and avoidance activity and found no significant difference of the peak time (Figures S5B1, S5B2, and S5G, left telencephalon, p = 0.0931, unpaired t test; right telencephalon, p = 0.0599, unpaired t test).