Figure 7. DA release during performance of the Instrumental Social Distress Task.

(A) Average DA release (n = 24 sessions, 9 rats) over time for no-shock press trials (blue), shock-self no press trials (red), shock-other no press trials (orange), and no-shock non-press trials (light blue dashed). See Figure 7—figure supplement 1 for an example session. Note that trials during which the recording rats were shocked could not be shown due to significant noise in the signal and that there were no significant differences between shock-other press and no-shock press trials during the reward epoch (ttest; p = 0.08). (B–D) During the outcome cue epoch (5 s after cue onset) indices comparing DA release between trial-types were computed for each session. Distributions of these indices are shown in B-D. B = Shk self no press minus Shk-other no press; C = Shk self no press minus No-shock press; D = Shk other no press minus No-shock press. (E) Distributions of the same indices as in B-D except shown by session (small dots) and rat (large dots) color coded by rat identity. See Figure 7—figure supplement 2 for regression between behavior and DA release by sessions and rat. Distributions of indices were deemed significantly shifted from zero via Wilcoxon (insets provide mean (µ) and p-value).

Figure 7—figure supplement 1. Example false-color plots for no-shock press, shock-self no press, and shock-other no press trial-types.

In the main text we show average DA release over all rats and sessions during performance of the instrumental social distress task to show high DA release during no-shock press trials and shock-self no press trials. DA release was also present on shock-other no press trials but attenuated compared to the other two trial-types. Here we show false-color plots that indicate voltammetric current (z-axis) plotted against applied scan potential (y-axis) and time (x-axis) averaged across one session for no-shock press (A), shock-self no press (B), and shock-other no-press (C) trials to further illustrate these findings.

Figure 7—figure supplement 2. Regressions between ‘self’ and ‘other’ for behavior and DA release.

In the main text we show that during performance of the Instrumental conspecific distress paradigm that on shock-self and shock-other trials where shock was avoided (i.e., non-press trials) that DA release was present during the cue and during the period after the lever was extended but not pressed. In the main text we report that the increase in DA during the cue period was not significantly different between self-shock-avoid trials and no-shock reward-press trials. This suggests that rats similarly value avoiding the shock and obtaining reward as we have shown in a previous publication (Gentry et al., 2016). Although DA release is also present on trials when the conspecific is spared, it is at significantly lower levels (as in Figure 7). Figure 7—figure supplement 2 (A) shows DA release on the shock-self and shock-other trials were correlated (p < 0.05; r² = 0.59). This correlation was also present in the behavior (Figure 7—figure supplement 2B). (B) To quantify the degree that the rats valued the reward relative to the avoiding the shock we subtracted percent lever pressing on shock trials from no-shock trials and subtracted the reaction times on shock trials from no-shock trials and then averaged them together, after dividing by the sum for each. This gave us one measure (i.e., ‘behavioral index’) of the how much the recording rat valued saving themselves and the conspecific based on two behavior measures. The majority of the points fell above zero consistent with the Figure 6E and F showing that rats chose to press less often and were slower to press on shock-self and shock-other trials. Figure 7—figure supplement 2B shows that two were correlated (p < 0.05; r² = 0.25). Thus, DA release and behavior reflect the value the rats place on avoiding shock. (C,D) Although DA release was high when rats avoided shock, we found no significant correlation between behavior and DA release on self (C: p = 0.81; r² = 0.003) and other (D: p = 0.36; r² = 0.038) shock trials.