Power spectral parameter variations after transcranial direct current stimulation in a bimanual coordination task

Transcranial direct current stimulation (tDCS) can shift neuronal membrane excitability by applying a weak slow electric current to the brain through the scalp. Attendant electroencephalography (EEG) can provide valuable information about the tDCS mechanisms. This study investigated the effects of anodal tDCS on parietal cortex and cerebellum activity to reveal possible modulation of spontaneous oscillatory brain activity. Timing of the tDCS priming protocol in relation to the intervention especially with respect to bimanual coordination task was also studied. EEG activity was measured in 120 healthy participants before and after sessions of anodal stimulation of the parietal cortex and cerebellum to detect the tDCS-induced alterations. Variations of the delta, theta, alpha, beta, and sensorimotor rhythm (SMR) power bands were analyzed using a MATLAB program. The results showed that anodal parietal and cerebellar tDCS cause changes in brain wave frequencies. They also showed an increase in alpha, beta, and SMR power bands during stimulation sessions for during stimulation parietal group (p <= .01). Also, theta, alpha, beta, and SMR power bands were increased in during stimulation cerebellum group in stimulation sessions and 48 h later (p <= .01). Moreover, the results revealed that the tDCS intervention led to a variety of activations in some areas of the brain. Altogether, the cerebellar tDCS during motor task had a significant improvement in off-line learning.

Automated summary

Transcranial direct current stimulation (tDCS) can modulate neuronal membrane excitability by applying a weak electric current to the brain, particularly in the parietal cortex and cerebellum. This study found that anodal tDCS led to changes in brain wave frequencies, with increases in alpha, beta, and SMR power bands during stimulation sessions for the parietal group, and increases in theta, alpha, beta, and SMR power bands in the cerebellum group during and after stimulation sessions. Additionally, tDCS intervention resulted in various brain activations, particularly showing significant improvement in off-line learning with cerebellar tDCS during a motor task.