cRETMS · Cerebellar Rhythmic Entrainment with Transcranial Magnetic Stimulation: A new approach for the study of cerebellar connections with the cortex.

Cerebellar Rhythmic Entrainment with Transcranial Magnetic Stimulation: A new approach for the study of cerebellar connections with the cortex.

Humans have the ability to adapt their actions according to environmental demands. Flexible realization of intentions and goals relies on making online predictions, processing external feedback and changing behaviour when needed. Imagine playing golf, and a light wind blowing towards the left. To send the ball in the right direction, you will need to adapt your stroke to compensate for the drift of the wind. If you are new to golf, correctly aiming your stroke may be challenging, and you may reach the target after numerous trials and errors. Particularly, the errors from prior strokes and the resulting feedback will be essential to adapt your movement. Adaptation is one of the most important features of the nervous system, as impairments of the brain network appointed to motor adaptation can seriously impact daily life. The cerebellum exerts a key role in adapting to environmental changes. It forms and stores internal models, i.e., sensory predictions based upon the expected movement results and compares them with actual sensory reafference. If a mismatch is detected, changes to the motor plan are implemented. Although the functional mechanisms of this process have been well studied in humans, the temporal dynamics mediating cerebellar activity are largely unknown, as most evidence comes mainly from direct recordings in animal models. This project aims at characterizing temporal biomarkers responsible to shape cerebellar local activity and its communication with other brain areas involved in the adaptation to environmental changes. Specifically, it aims to 1) characterize cerebellar oscillatory activity both at rest and during motor adaptation, 2) determine the relationships between the cerebellar oscillatory activity, its structural connections with areas and structures of the motor network, and motor adaptation, 3) assess whether externally and non-invasively boosting such oscillations can improve visuomotor adaptation. Preliminary results show two possible biomarkers subtending the communication between the cerebellum and the cortex that support motor adaptation, i.e., beta (20 Hz) and gamma frequency (40 Hz). As a side project (not initially considered within MCSA goals), we were also able to show that by modulating gamma activity with transcranial alternate current stimulation (tACS), it is possible to improve motor adaptation in Writer’s cramp (WC) dystonic patients who show abnormal cerebellar gamma oscillatory activity in the cerebellum.

Data: CORDIS, © European Union