title: Distinct basal ganglia territories are engaged in early and advanced motor sequence learning.
abstract: In this study, we used functional MRI (fMRI) at high field (3T) to track the time course of activation in the entire basal ganglia circuitry, as well as other motor-related structures, during the explicit learning of a sequence of finger movements over a month of training. Fourteen right-handed healthy volunteers had to practice 15 min daily a sequence of eight moves using the left hand. MRI sessions were performed on days 1, 14 and 28. In both putamen, activation decreased with practice in rostrodorsal (associative) regions. In contrast, there was a significant signal increase in more caudoventral (sensorimotor) regions of the putamen. Subsequent correlation analyses between signal variations and behavioral variables showed that the error rate (movement accuracy) was positively correlated with signal changes in areas activated during early learning, whereas reaction time (movement speed) was negatively correlated with signal changes in areas activated during advanced learning stages, including the sensorimotor putamen and globus pallidus. These results suggest the possibility that motor representations shift from the associative to the sensorimotor territories of the striato-pallidal complex during the explicit learning of motor sequences, suggesting that motor skills are stored in the sensorimotor territory of the basal ganglia that supports a speedy performance.
authors.affiliation: Center for Magnetic Resonance Research/Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA. lehericy@cmrr.umn.edu
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehéricy
authors.forename: Habib
authors.initials: H
authors.lastname: Benali
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Van de Moortele
authors.forename: Mélanie
authors.initials: M
authors.lastname: Pélégrini-Issac
authors.forename: Tobias
authors.initials: T
authors.lastname: Waechter
authors.forename: Kamil
authors.initials: K
authors.lastname: Ugurbil
authors.forename: Julien
authors.initials: J
authors.lastname: Doyon
mesh_terms: D000328:Adult; D001479:Basal Ganglia / Q000502:physiology*; D002531:Cerebellum / Q000502:physiology; D005260:Female; D005385:Fingers / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology