Figure 4.

Effect of nomifensine infusion on average timing functions. Average maximum percent response (lever pressing) rate in rats trained to time a 40 s criterion signaled by a visual stimulus when presented with a neutral distracter (CTRL group, upper panels) or an emotionally charged distracter (noise previously paired with foot shock, FEAR group, lower panels). Left panels: Peak interval (PI) trials (without noise): nomifensine has no reliable effects in either group. Right panels: Peak interval with noise (PI + N) trials (with noise): when emotionally charged (FEAR group), the distracter shifts the response function rightward considerably relative to neutral events (CTRL); nomifensine reduces the delaying effect of the distracter only when the distracter is emotionally charged (FEAR group). The gray bars indicate the presentation of the auditory distracters.