Experience-dependent changes in neuronal processing in the nucleus accumbens shell in a discriminative learning task in differentially housed rats.

Environmental enrichment is associated with enhanced learning of complex tasks, attenuated seeking of natural and drug rewards, and altered function of the nucleus accumbens (NAcc), a brain region involved in goal-directed behavior. For example, during acquisition of a discriminative learning task, neurons in the NAcc core subregion are more responsive to discrete, goal-directed movements in rats raised in an enriched condition (EC) relative to an isolated condition (IC), but as learning materialized, this enhanced responsiveness shifts to the cues that predict these movements. Here, we report that these results do not extend to NAcc shell: neuronal responses in this subregion are similar in EC and IC rats during goal-directed movement and the presentation of associative cues both during and after task acquisition.

AA/12-Lipoxygenase Signaling Contributes to Inhibitory Learning in Hermissenda Type B Photoreceptors.

Conditioned inhibition (CI) is a major category of associative learning that occurs when an organism learns that one stimulus predicts the absence of another. In addition to being important in its own right, CI is interesting because its occurrence implies that the organism has formed an association between stimuli that are non-coincident. In contrast to other categories of associative learning that are dependent upon temporal contiguity (pairings) of stimuli, the neurobiology of CI is virtually unexplored.