Technical Program

Paper Detail

Paper: PS-1A.16
Session: Poster Session 1A
Location: Symphony/Overture
Session Time: Thursday, September 6, 16:30 - 18:30
Presentation Time:Thursday, September 6, 16:30 - 18:30
Presentation: Poster
Paper Title: Repetition Suppression during Movement Execution Reflects Different Mechanisms in the Striatum than in the Neocortex
Manuscript:  Click here to view manuscript
Authors: Eva Berlot, Nicola J. Popp, Jörn Diedrichsen, Western University, Canada
Abstract: Repetition suppression (RS) provides an important tool to investigate brain representations. Repetition of the same stimulus evokes a reduction in elicited brain activity. While the reduction in activity is consistently observed across modalities and species, it is unclear what mechanisms drive this effect. Several models of RS have been proposed, which vary in their prediction of stimulus ‘tuning’ in the second repetition. Here we examined RS mechanisms in two motor cortical areas and the striatum while participants executed motoric finger sequences, twice in a row. We distinguished the RS models by investigating the changes in the sequence-dependent fMRI activity patterns in concert with the changes in overall activity. In the striatum, we observed that the tuning for individual sequences is ‘sharpened’ on the second execution, whereas in the cortex we found a ‘fatigued’ representation. This dissociation might indicate different computational roles along the cortico-striatal circuitry, with the striatum solving the selection problem, and signaling its novelty to the cortex.