How brain circuitry is reorganized during learning, set-shifting is the focus of our project. To adapt behavior to changes in the external and internal environment, one must ignore established stimulus-reinforcement contingencies and shift attention to a previously irrelevant stimulus. Such behavior flexibility is known as attentional set-shifting, it engages several different brain regions and it is strongly influenced by catecholamine neuromodulators. We identify multiple brain regions (including the hippocampus,prefrontal cortex and the striatum) activated by an extradimensional set-shifting task using c-fos immunohistochemistry and record simultaneously neuronal activity and local field potentials in these ROI regions in behaving animals during its acquistion and set-shifting by multi-channel recording technique for further understanding of the neural mechanisms.

We characterized cell responses as well as LFP coherence changes upon learning. These analyses showed that activity levels changed upon learning stage as well as set-shifting and were selective for the learned rule (visual cue discrimination vs spatial orientation) in the various striatum and prefrontal cortex zones. This indicates that different steps of learning correspond to neural network phenomena and are not simply dependent upon a single structure, consistent with the c-fos activation results.