Progress in brain research
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An impressive array of neural processing appears to be dedicated to the extraction of reward-related information from environmental stimuli and use of this information in the generation of goal-directed behaviors. While other structures are certainly involved in these processes, the characteristics of activations seen in mesencephalic dopamine neurons, striatal neurons and neurons of the orbitofrontal cortex provide distinct examples of the different ways in which reward-related information is processed. In addition, the differences in activations seen in these three regions demonstrate the different roles they may play in goal-directed behavior. ⋯ As such they would be of use for the execution of appropriate goal-directed behaviors in response to known environmental stimuli, as well as for generating behaviors in response to novel stimuli that may be associated with desirable goals. 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. These activations would serve a function similar to those striatal neurons that encode exclusively reward-related information in situations in which only a single outcome is obtainable. (ABSTRACT TRUNCATED)