The in vivo reduction of afferent facilitation induced by low frequency electrical stimulation of the motor cortex is antagonized by cathodal direct current stimulation of the cerebellum

Abstract

BackgroundLow-frequency electrical stimulation to the motor cortex (LFSMC) depresses the excitability of motor circuits by long-term depression (LTD)-like effects. The interactions between LFSMC and cathodal direct current stimulation (cDCS) over the cerebellum are unknown.MethodsWe assessed the corticomotor responses and the afferent facilitation of corticomotor responses during a conditioning paradigm in anaesthetized rats. We applied LFSMC at a frequency of 1 Hz and a combination of LFSMC with cDCS.ResultsLFSMC significantly depressed both the corticomotor responses and the afferent facilitation of corticomotor responses. Simultaneous application of cDCS over the cerebellum antagonized the depression of corticomotor responses and cancelled the depression of the afferent facilitation.ConclusionOur results demonstrate that cDCS of the cerebellum is a potent modulator the inhibition of the motor circuits induced by LFSMC applied in vivo. These results expand our understanding of the effects of cerebellar DCS on motor commands and open novel applications for a cerebellar remote control of LFSMC-induced neuroplasticity. We suggest that the cerebellum acts as a neuronal machine supervising not only long-term potentiation (LTP)-like effects, but also LTD-like effects in the motor cortex, two mechanisms which underlie cerebello-cerebral interactions and the cerebellar control of remote plasticity. Implications for clinical ataxiology are discussed.

State-Dependent Entrainment of Prefrontal Cortex Local Field Potential Activity Following Patterned Stimulation of the Cerebellar Vermis

“…The stimulation in the cerebellar vermis, in reaching the prefrontal cortex, likely coursed through the fastigial nucleus and then to the thalamus (Bostan et al, 2013; Lisberger and Thach, 2013). Stimulation of Purkinje cells, in the outermost layer of the cerebellum, leads to changes in the cerebellar output, which in turn modulates the output of deep cerebellar nuclei (DCN) (Oulad Ben Taib and Manto, 2013, 2016; Das et al, 2017). Because inputs from Purkinje cells to the DCN are inhibitory, increased activation of Purkinje cells with high frequency stimulation (Maeda et al, 2000b; Hallett, 2007) inhibits the tonic activity of the DCN.…”

Consensus Paper: Experimental Neurostimulation of the Cerebellum

“…So far, it is hypothesized that (1) on-line benefits to stimulation might be the result of directly modulating Purkinje neuron activity, whereas off-line benefits may be the result from long-lasting changes to the activity of Golgi cells [267, 268], and (2) severe cerebellar atrophy with a major loss of neurons above a threshold is unlikely to respond well to non-invasive stimulation. Stimulating patients earlier, stimulating multiple sites, or delivering distinct modes of stimulation [265] are being considered, but have not been validated as viable alternative approaches, yet.…”

Effects of Anodal Cerebellar Transcranial Direct Current Stimulation on Movements in Patients with Cerebellar Ataxias: A Systematic Review

“…A total of 397 records were identified from the databases and reduced to 57 records after removal of duplicates (Figure 1). Among the 57 records, 52 records were further excluded: 40 records were reviews [6,16,18,19,22,[25][26][27][28][29][30][31][32][33][34], conference proceedings [35][36][37][38][39][40], responses [41,42], editors' notes [43], letters to the editors [44], reports [45], corrections [46], updates [47], theoretical papers [48], commentaries [49,50], book chapters [51], published protocols [52], or clinical trials registration records [53][54][55][56][57][58][59]; two studies did not recruit human participants [60,61]; one study did not recruit patients with cerebellar ataxias [62]; one study did not apply tDCS [63]; three studies used cranial electrotherapy stimulation, CES…”