Jesse H. Goldberg, Department of Neurobiology, Cornell University, will present seminar. Professor Carl Franck, host.
Seminar Title: Signals and circuits underlying performance evaluation in singing birds
Abstract: Virtually all of our behaviors are learned by a gradual process of trial and error, but the neural mechanisms of performance evaluation remain poorly understood. For example, when practicing a piano concerto, how do you know if you strike the right or wrong note? The problem is that there is nothing intrinsically ‘good’ or ‘bad’ about the sound of A-sharp – it depends if that’s the key you wanted to strike at that time of the song. In contrast to reward processing, performance evaluation requires sensory feedback to be compared with internal benchmarks that change from moment to moment in a sequence. In tasks where animals seek primary rewards such as food or juice, dopamine neurons in the ventral tegmental area (VTA) encode reward prediction error, the difference between reward predicted and obtained. Yet it is not known if dopamine activity also evaluates behaviors that are not learned for primary rewards but are instead learned by matching performance outcomes to internal goals. We recorded dopamine neurons in singing zebra finches as we controlled perceived error with distorted auditory feedback. Dopamine neurons exhibited phasic suppressions after distorted syllables, consistent with a worse-than-predicted outcome, and exhibited phasic activations at the precise moment of the song when a predicted distortion did not occur, consistent with a better-than-predicted outcome. Thus dopamine activity encodes performance error by evaluating the quality of ongoing behavior relative to internal performance benchmarks.
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