Cerebellar Transcranial Direct Current Stimulation Modulates Anticipatory Postural Adjustments in Healthy Adults

During forward swinging of the arm, the central nervous system must anticipate the effect of upraising upon the body. Little is known about the cerebellar network that coordinates these anticipatory postural adjustments (APAs). Stimulating different cerebellar regions with transcranial direct current stimulation (tDCS) and with different polarities modulated the APAs. We used surface electromyography (sEMG) to measure muscle activities in a bilateral rapid shoulder flexion task. The onset of APAs was altered after tDCS over the vermis, while the postural stability and the kinematics of arm raising were not affected. To our knowledge, this is the first human cerebellar-tDCS (c-tDCS) study to separate cerebellar involvement in core muscle APAs in bilateral rapid shoulder flexion. These data contribute to our understanding of the cerebellar network supporting APAs in healthy adults. Modulated APAs of the erector spinae by tDCS on the vermis may be related to altered cerebellar brain inhibition (CBI), suggesting the importance of the vermal-cerebral connections in APAs regulation.

Automated summary

During forward swinging of the arm, the cerebellar network plays a crucial role in coordinating anticipatory postural adjustments (APAs), which are necessary to anticipate the effect of arm raising on the body. In this study, transcranial direct current stimulation (tDCS) was used to modulate different cerebellar regions and their polarities, leading to changes in the onset of APAs without affecting postural stability and arm raising kinematics. This study provides valuable insights into the cerebellar network involved in APAs and highlights the importance of cerebellar-brain connections in regulating APAs.