Neuron
Volume 84, Issue 5, 3 December 2014, Pages 1034-1048
Journal home page for Neuron

Article
The Habenulo-Raphe Serotonergic Circuit Encodes an Aversive Expectation Value Essential for Adaptive Active Avoidance of Danger

https://doi.org/10.1016/j.neuron.2014.10.035Get rights and content
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Highlights

  • Negative reward expectation value is represented in the ventral habenula

  • The habenulo-raphe pathway is necessary for active avoidance learning

  • The habenulo-raphe pathway is dispensable for classical fear conditioning

  • Activation of the ventral habenula is sufficient for induction of avoidance behavior

Summary

Anticipation of danger at first elicits panic in animals, but later it helps them to avoid the real threat adaptively. In zebrafish, as fish experience more and more danger, neurons in the ventral habenula (vHb) showed tonic increase in the activity to the presented cue and activated serotonergic neurons in the median raphe (MR). This neuronal activity could represent the expectation of a dangerous outcome and be used for comparison with a real outcome when the fish is learning how to escape from a dangerous to a safer environment. Indeed, inhibiting synaptic transmission from vHb to MR impaired adaptive avoidance learning, while panic behavior induced by classical fear conditioning remained intact. Furthermore, artificially triggering this negative outcome expectation signal by optogenetic stimulation of vHb neurons evoked place avoidance behavior. Thus, vHb-MR circuit is essential for representing the level of expected danger and behavioral programming to adaptively avoid potential hazard.

Cited by (0)

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Present address: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria

9

Present address: Tokyo Medical and Dental University, Medical Research Institute, Tokyo 113-8510, Japan

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Present address: The Institute of Scientific Research and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan