Abstract

Motor adaptation- an error based learning process, involves contributions from multiple cortical and subcortical regions of the human brain organized in widespread networks, in which the cerebellum seems to play a fundamental role. Large-scale synchronization of oscillatory activity could be an effective strategy to integrate the cerebellar function with the rest of the system, however there is no direct evidence of this proposal. To investigate the impact of cerebellar stimulation on motor adaptation and brain connectivity, we conducted a study where 18 healthy participants carried out a visuo-motor adaptation task in parallel to receive a protocol of cerebellar transcranial alternating stimulation (tACS), a form of electrical stimulation that could entrain the nervous system in a frequency-specific oscillatory activity. Applying tACS in different days, we yielded evidence that tACS at 50Hz, but not at 20Hz or sham, accelerated the rate of adaptation in parallel to enhance the event-related power modulation and phase-synchronization. This effect was evident for the comparison between tACS-50Hz and sham in a range of alpha and beta band (8-30 Hz). Notably, active tACS conditions (50Hz and 20Hz) imposed a particular modulation of neural activity that prevent a direct comparison between them in the 13-30Hz range. No changes in visuomotor coordination were detected. Our results support the notion that purkinje cell-deep nucleus, a key network for motor error processing, could be the target of tACS. Overall, tACS demonstrated the potential to entrain the nervous system in a function-related oscillatory activity, which bring the opportunity to modulate cognitive functions.