Modulation of cerebellar excitability by frequency-specific noninvasive alternating current stimulation
Year: 2021
Type: article
Abstract: Oscillatory activity in the cerebellum plays a fundamental role in neuronal processing, plasticity, and functional implementation of motor and cognitive behavior. The emergence of transcranial alternating current stimulation (tACS), a technique capable of boosting specific brain oscillations, presents an intriguing strategy to better understand human cerebellar physiology. In this talk, I will show how applying tACS over the cerebellum can modulate cerebellar excitability. To do this, a well-characterized dual-coil transcranial magnetic stimulation paradigm was utilized to measure the connectivity between the cerebellar and M1 (CBI). Specifically, I will demonstrate that CBI only changes during the application of 5Hz cerebellar tACS, but not immediately following tACS at this frequency nor when applying 50-Hz tACS. Interestingly, we also found no changes to M1 intracortical circuits (i.e. SICI) or sensorimotor interaction (i.e. SAI). This indicates that the effects of 5Hz tACS over the cerebellum are site-specific and do not affect the cortex. Overall, this indicates that cerebellar tACS can modulate cerebellar excitability in a time- and frequency-dependent manner without inducing any long-lasting effects (i.e. plasticity). Since the rhythmic activity of neuronal populations plays a crucial role in brain plasticity, I will also present data that shows the effects of co-stimulating the cerebellum with tACS and continuous theta-burst stimulation (cTBS). As cTBS is known to induce long-term potentiation-like plasticity, one prediction is that tACS may increase and prolong the effects of cTBS. Preliminary results show that only theta boosts cerebellar excitability and reduces cortical excitability. Therefore, this co-stimulation approach may present as a novel strategy to enhance mechanisms of cerebellar plasticity, thereby lending itself to future applications in the neurorehabilitation setting and also for facilitating learning in future behavioral studies. Keywords: TMS, Cerebellum, tACS, Modulation
Source: Brain stimulation
Author: Danny Spampinato
Institution: Fondazione Santa Lucia
Language: English
Subfield: Neurology
Field: Neuroscience
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,310
OpenAlex ID: W3216702147