Striatal and medial temporal lobe functional interactions during visuomotor associative learning.

A network of regions including the medial temporal lobe (MTL) and the striatum are integral to visuomotor associative learning. Here, we evaluated the contributions of the structures of the striatum and the MTL, as well as their interactions during an arbitrary associative learning task. We hypothesized that activity in the striatum would correlate with the rate of learning, while activity in the MTL would track how well associations were learned. Further, we expected functional correlations to show both facilitative as well as competitive relationships depending on the regions involved. Results showed that activity throughout the striatum was modulated by the rate of learning, while the sensorimotor and ventral striatum were also modulated by probability correct. Across the MTL, activity correlated with the probability of being correct, while the perirhinal cortex and right parahippocampal cortex were modulated by the rate of learning. The activity in the ventral striatum robustly coupled with activity in the MTL during learning, while interactions between the associative striatum and the MTL showed the opposite pattern. These findings suggest dissociable computational roles for different subregions of the striatum and MTL. These subregions interact in distinct ways, perhaps forming functionally integrated networks during the learning of arbitrary associations.