Frequency-Dependent Effects of Transcranial Alternating Current Stimulation on Cerebro-Cerebellar Connectivity and...

Area of Science:

• Neuroscience
• Motor Control
• Brain Stimulation

Background:

• The cerebellum plays a crucial role in sensorimotor functions.
• Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique with potential for modulating neural activity.
• The specific effects of different tACS frequencies on cerebro-cerebellar networks and sensorimotor performance remain unclear.

Purpose of the Study:

• To investigate the frequency-specific effects of cerebellar tACS on cerebro-cerebellar effective connectivity and sensorimotor performance.
• To compare the impact of low-frequency (10 Hz) and high-frequency (70 Hz) tACS against sham stimulation.

Main Methods:

• A within-participant, single-blind, sham-controlled study design was employed.
• Magnetic resonance imaging (MRI)-based computational modeling determined optimal tACS current intensity for a cerebellar montage (F6-O2).
• Participants received 20-minute sessions of 10 Hz, 70 Hz, or sham tACS, followed by assessments of electroencephalogram (EEG)-based cerebro-cerebellar connectivity and sensorimotor task performance.

Main Results:

• Computational modeling identified 2.0 mA as the optimal current for the cerebellar montage.
• 10 Hz cerebellar tACS generally increased effective connectivity, while 70 Hz tACS predominantly decreased it.
• Both 10 Hz and 70 Hz tACS significantly improved sensorimotor performance by reducing errors compared to sham stimulation.

Conclusions:

• Cerebellar tACS exhibits frequency-dependent effects on cerebro-cerebellar network connectivity.
• Despite opposing neural effects, both low and high tACS frequencies can enhance sensorimotor performance.
• These findings suggest that different neural pathways can be recruited to facilitate motor learning through cerebellar tACS.