2015年3月9日月曜日

Activation of Dorsal Raphe Serotonergic Neurons Promotes Waiting but Is Not Reinforcing

Madalena S. Fonseca, Masayoshi Murakami, Zachary F. Mainen
Current Biology, Volume 25, Issue 3, 2 February 2015, Pages 306–315

背側縫線核(dorsal raphe nucleus)のセロトニン・ニューロンの活動は「報酬が出るまで待つ」ことに重要だが、強化学習には効いていない。

Background
The central neuromodulator serotonin (5-HT) has been implicated in a wide range of behaviors and affective disorders, but the principles underlying its function remain elusive. One influential line of research has implicated 5-HT in response inhibition and impulse control. Another has suggested a role in affective processing. However, whether and how these effects relate to each other is still unclear.

Results
Here, we report that optogenetic activation of 5-HT neurons in the dorsal raphe nucleus (DRN) produces a dose-dependent increase in mice’s ability to withhold premature responding in a task that requires them to wait several seconds for a randomly delayed tone. The 5-HT effect had a rapid onset and was maintained throughout the stimulation period. In addition, movement speed was slowed, but photostimulation did not affect reaction time or time spent at the reward port. Using similar photostimulation protocols in place preference and value-based choice tests, we found no evidence of either appetitive or aversive effects of DRN 5-HT neuron activation.

Conclusions
These results provide strong evidence that the efficacy of DRN 5-HT neurons in promoting waiting for delayed reward is independent of appetitive or aversive effects and support the importance of 5-HT in behavioral persistence and impulse control.

0 件のコメント:

コメントを投稿