A Pilot Study on the Effects of Transcranial Direct Current Stimulation on Brain Rhythms and Entropy during Self-Paced Finger Movement using the Epoc Helmet

Abstract

Transcranial direct current stimulation (tDCS) of the cerebellum is emerging as a novel non-invasive tool to modulate the activity of the cerebellar circuitry. In a single blinded study, we applied anodal tDCS (atDCS) of the cerebellum to assess its effects on brain entropy and brain rhythms during self-paced sequential finger movements in a group of healthy volunteers. Although wearable electroencephalogram (EEG) systems cannot compete with traditional clinical/laboratory set-ups in terms of accuracy and channel density, they have now reached a sufficient maturity to envision daily life applications. Therefore, the EEG was recorded with a comfortable and easy to wear 14 channels wireless helmet (Epoc headset; electrode location was based on the 10–20 system). Cerebellar neurostimulation modified brain rhythmicity with a decrease in the delta band (electrode F3 and T8, p < 0.05). By contrast, our study did not show any significant change in entropy ratios and laterality coefficients (LC) after atDCS of the cerebellum in the 14 channels. The cerebellum is heavily connected with the cerebral cortex including the frontal lobes and parietal lobes via the cerebello-thalamo-cortical pathway. We propose that the effects of anodal stimulation of the cerebellar cortex upon cerebral cortical rhythms are mediated by this key-pathway. Additional studies using high-density EEG recordings and behavioral correlates are now required to confirm our findings, especially given the limited coverage of Epoc headset.

Consensus Paper: Experimental Neurostimulation of the Cerebellum

“…Furthermore, studies on the effects of cerebellar tDCS on healthy patients have revealed which circuits and functions can be modulated. Similar to DBS, tDCS impacts the cerebellum, the thalamus, the basal ganglia, and the cortex, as measured by the cerebellar brain inhibition (CBI), EEG, and behavioral indices [201–204]. For example, tDCS has been shown to modulate CBI in healthy subjects [205].…”

Consensus Paper: Cerebellum and Emotion

“…The most recent studies show that cerebellar stimulation using continuous theta-burst stimulation (cTBS) is NMDA receptordependent and most likely involves long-term potentiation (LTP) and long-term depression (LTD) [11]. This translates to an altered functional connectivity with remote cortical areas [12], which is also observed after transcranial alternating current stimulation (tACS) [13] and after transcranial direct current stimulation (tDCS) [14]. Although tACS and tDCS modulate cerebellar plasticity and functional connectivity, these electric techniques most likely operate in a different way than the transcranial magnetic stimulation (TMS) techniques such as cTBS [10].…”

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…”