Periodic Reporting for period 1 - cRETMS (Cerebellar Rhythmic Entrainment with Transcranial Magnetic Stimulation: A new approach for the study of cerebellar connections with the cortex.)
Reporting period: 2021-01-01 to 2022-12-31
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.
The second part of my work consisted of addressing two research questions: (1) does pre-movement beta oscillatory activity (20 Hz) reflect the ability of the cerebellar-cortical network to adapt to the changes of the environment? (2) can we enhance motor adaptation by entraining cerebellar oscillations? In the first study, we analysed the data of 17 healthy participants performing a visuomotor adaptation task while their brain oscillatory activity was recorded with magnetoencephalography (MEG). We aimed to characterize pre-movement oscillatory related to the adaptation to visual biases. Preliminary results show a modulation of anticipatory beta activity (20 Hz) based on motor adjustments due to the bias, localized in a network including the right cerebellum (crus II), the left parietal inferior lobule and the right frontal inferior lobe. Finally, I also collaborated on a second study in which we analysed data from 16 Writer’s Cramp (WC) dystonic patients and age- and gender-matched healthy controls who performed the visuomotor task during MEG recordings. Here, we aimed at determining whether cerebellar oscillations related to motor adaptation are affected in WC patients. Furthermore, we wanted to determine whether it is possible to boost motor adaptation by driving cerebellar oscillations with transcranial alternating current stimulation (tACS). Transcranial ACS is an electrical non-invasive stimulation technique that can entrain brain oscillations and modulate motor performance. Our results show that anticipatory cerebellar activity in WC patients, compared to healthy controls, was normal at beta frequency but abnormal at gamma frequency, which was also related to aberrant adaptation. Furthermore, tACS (but not placebo stimulation) was able to compensate for cerebellar gamma dysrhythmia and increase patients’ learning performance via modulation of a thalamic relay. The findings of the second study are currently being submitted for publication.
The results of this project have been presented at 2 national and 3 international conferences (1 poster award). One study is being prepared for submission to a top-tier journal and one abstract has been published.