Figure 2

Decrease of tonic dopamine level degrades social learning. (A) Prior to each exposure session, the naïve observer gerbils were given an injection of a dopamine receptor antagonist (5 males; age = 99.5 ± 8.6 days; see “Methods” section for details). After 15–20 min of recovery, the exposure session began (left) with same-sex demonstrators (age = 138 ± 3.7). No drug was injected during the practice sessions (right). (B) Similar to A, except that saline was injected to the observers (5 males; age = 104.3 ± 10.7) prior to each exposure session (left) with the demonstrators (age = 143 ± 5.4). No drug was injected during the practice sessions (right). (C) Individual and mean ± SEM of the overall number of Go and Nogo trials performed by the observer gerbils during the practice sessions (antagonist-injected observers in red and saline-injected observers in blue). (D) Individual and mean ± SEM of the performance d′ of the observer gerbils as a function of practice sessions. (E) Prior to each exposure session, the yoked reward observer gerbils were given an injection of a dopamine receptor antagonist (4 males; age = 111.3 ± 8.9). After 15–20 min of recovery, the exposure session began (left) with the demonstrators (age = 166 ± 4.5). No drug was injected during the practice sessions (right). (F) Similar to E, except that saline was injected to the observers (5 males; age = 110.3 ± 8.5) prior to each exposure session (left) with the demonstrators (age = 119 ± 5.7). No drug was injected during the practice sessions (right). (G) Similar to C for the yoked reward observers. (H) Similar to D for the yoked reward observers.