The role of habenula in dopamine reward prediction errors


April 30, 2014 - 1:00pm
NW 243
About the Speaker
Ju Tian (Uchida Lab)

To behave optimally in an uncertain environment, we must integrate information about reward and punishment. In addition to the absolute amount of reward, it is crucial to know the amount of reward relative to our expectation. In the brain, it has been found that both midbrain dopamine neurons and lateral habenula neurons encode the discrepancy between actual reward and expected reward, or reward prediction error (RPE). Interestingly, they do so with opposite signs. An influential hypothesis is that the lateral habenula sends the reward prediction error signal to dopamine neurons. To study what information is conveyed from habenula to dopamine neurons, we recorded from optogenetically-identified dopamine neurons while mice performed a conditioning task. We compared dopamine neurons’ responses in animals where the habenula had been electrolytically lesioned or left intact.

We found that habenula lesions decreased dopamine neurons’ RPE response. Unexpectedly, dopamine neurons’ response to punishing airpuff stimuli was not impaired by habenula lesion. These results suggest that different mechanisms may underlie responses to rewarding and aversive stimuli in dopamine neurons.