Short timescale modulation of cortical and cerebellar activity in the early phase of motor sequence learning: an fMRI study

Motor learning is a multi-stage process, in which the involvement of different brain regions is related to the specific stage. We aimed at characterising short timescale changes of brain activity induced by motor sequence learning. Twenty healthy volunteers performed a serial reaction time task during an MRI session in a 3 T scanner. The task consisted of two conditions: repeated and random, that were compared over the whole fMRI run, as well as within sections, to investigate brain activity modulating related to the learning stage. The whole fMRI run analysis showed a stronger response for the repeated condition in fronto-parietal regions, cerebellum and thalamus. The analysis on sections showed initially increased right cerebellar activity. In the subsequent phase, bilateral cerebellar activity was observed, while no increased activity was seen in the last phase, when the learning was established. At the neocortical level, the repeated condition showed stronger activity at first in fronto-parietal regions bilaterally, then lateralized to the right hemisphere in the last learning phase. This study showed short time scale brain activity modulation in cortical and cerebellar regions with involvement of different brain regions over the learning process not restricted to the motor circuit.