PMID-11105648 Involvement of basal ganglia and orbitofrontal cortex in goal-directed behavior.
- Many regions have a complex set of activations, but dopamine neurons appear more homogenous: they report the error in reward prediction.
- "The homogeneity of responsiveness across the population of dopamine neurons indicates that this error signal is widely broadcast to dopamine terminal regions where it could provide a teaching signal for synaptic modifications underlying the learning of goal-directed appetitive behaviors."
- Signals are not contingent on the type of behavior needed to obtain the reward, and hence represent a relatively 'pure' reward prediction error.
- Unlike dopamine neurons, many striatal neurons respond to predicted rewards, although at least some may reflect the relative degree of predictability in the magnitude of the responses to reward.
- Neuronal activations in the orbitofrontal cortex appear to involve less integration of behavioral and reward-related information, but rather incorporate another aspect of reward, the relative motivational significance of different rewards.
- Processing is hierarchical (or supposed to be so):
- Dopamine neurons provide a relatively pure signal of an error in reward prediction,
- Striatal neurons signal not only reward, but also behavioral contingencies,
- Orbitofrontal neurons signal reward and incorporate relative reward preference.
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