— 국제 심포지움 시리즈 –

건국대학교 생명과학특성학과/대학원 생명과학과

4단계 BK21 미래통합형 생명과학 인재양성 사업단

Dopamine transient: prediction or prediction error?

Transient changes in the firing of dopamine neurons to rewards have been proposed to signal temporal difference prediction errors that drive associative learning. A key feature of this error signal is the backpropagation of the dopamine response to cue that are good predictors of rewards. This cue-evoked dopamine response is considered to represent an error signal, that is, the excess or unpredicted future reward predicted by the cue. The consequence of such a cue-evoked signal is that it should reinforce learning in a manner similar to that seen to actual rewards. Evidence for this position is sparse. Most correlative studies showing that dopamine transients behave as prediction errors (and not predictions as is typically the interpretation of cue-evoked firing in other brain regions) focus on the reward-evoked response, and there are no causal studies showing that the cue-evoked dopamine response is necessary for learning. Causal studies are particularly tricky since it is important to both show that the cue-evoked response is required for learning while also ruling out the possibility that this is simply because it carries the reward prediction rather than the prediction error signal. To provide insight into whether the cue-evoked dopamine signal is a prediction about upcoming reward or a prediction-error, we used optogenetic suppression or shunting of the dopamine transient to a CS+ in the context of second-order conditioning and also blocking. The results show that disrupting this signal impairs the ability of the CS+ to reinforce learning in second-order conditioning, without affecting the ability of the CS+ to serve as a predictor of subsequent reward, in blocking. These results support the proposal that the dopamine transient evoked by cues and rewards serves as a temporal difference error.

연사: Mihaela Iordanova, PhD, Professor, Department of Psychology/Centre for Studies in Behavioural Neurobiology, Concordia University

일시: 2021년 4월 30일 (금) 오전 9시~10시

Zoom 회의 참가

https://us02web.zoom.us/j/87501576901?pwd=d0NEa0pXSXpLaVVZNXVKbGl2VFlWUT09

회의 ID: 875 0157 6901

암호: 309832