2015年3月20日金曜日

Observation of Reward Delivery to a Conspecific Modulates Dopamine Release in Ventral Striatum

Vadim Kashtelyan, Nina T. Lichtenberg, Mindy L. Chen, Joseph F. Cheer, Matthew R. Roesch
Current Biology, Volume 24, Issue 21, 3 November 2014, Pages 2564–2568

「他個体が報酬を得ている」ことの観察が、腹側線条体(ventral striatum)におけるドーパミンの放出に影響を与える。

Dopamine (DA) neurons increase and decrease firing for rewards that are better and worse than expected, respectively. These correlates have been observed at the level of single-unit firing and in measurements of phasic DA release in ventral striatum (VS) [1, 2, 3, 4, 5, 6, 7, 8, 9 and 10]. Here, we ask whether DA release is modulated by delivery of reward, not to oneself, but to a conspecific. It is unknown what, if anything, DA release encodes during social situations in which one animal witnesses another animal receive reward. It might be predicted that DA release will increase, suggesting that watching a conspecific receive reward is a favorable outcome. Conversely, DA release may be entirely dependent on personal experience, or perhaps observation of receipt of reward might be experienced as a negative outcome because another individual, rather than oneself, receives the reward. Our data show that animals display a mixture of affective states during observation of conspecific reward, first exhibiting increases in appetitive calls (50 kHz), then exhibiting increases in aversive calls (22 kHz) [11, 12, 13 and 14]. Like ultrasonic vocalizations (USVs), DA signals were modulated by delivery of reward to the conspecific. We show stronger DA release during observation of the conspecific receiving reward relative to observation of reward delivered to an empty box, but only on the first trial. During the following trials, this relationship reversed: DA release was reduced during observation of the conspecific receiving reward. These findings suggest that positive and negative states associated with conspecific reward delivery modulate DA signals related to learning in social situations.

0 件のコメント:

コメントを投稿