Corticostriatal Plasticity Established by Initial Learning Persists After Behavioral Reversal

The neural mechanisms that allow animals to adapt their previously learned associations in response to changes in the environment remain poorly understood. To probe the synaptic mechanisms that mediate such adaptive behavior, we trained mice on an auditory-motor reversal task, and tracked changes in the strength of corticostriatal synapses associated with the formation of learned associations. Using a ChR2-based electrophysiological assay in acute striatal slices, we measured the strength of these synapses after animals learned to pair auditory stimuli with specific actions. Here we report that the pattern of synaptic strength initially established by learning remains unchanged even when the task contingencies are reversed. Our results suggest that synaptic changes associated with the initial acquisition of this task are not erased or over-written, and that behavioral reversal of learned associations may recruit a separate neural circuit.