tDCS possibly stimulates glial cells

ObjectiveExplore the possibility that transcranial direct current stimulation (tDCS) of the brain affects glial cells.MethodsCable theory is used to estimate roughly transmembrane potential in neurons and glial cells. tDCS is additionally compared to neuronal stimulation techniques for which the mechanisms are well known.ResultsTheoretical calculations indicated that tDCS can affect the glial transmembrane potential. The change is similar to what is physiologically observed in astrocytes during neuronal activation. In neurons, transmembrane potential changes are much weaker than the threshold for eliciting action potentials.ConclusionsBased on simplified cable theory, tDCS may affect glial cells’ transmembrane potential and thereby the balance of neurotransmitters. No physiological evidence or proof is available, however.SignificanceIt is an exciting possibility that tDCS could manipulate glial cells because they are active participants in brain function, and have multiple essential roles in the human brain. This approach may change greatly the therapeutic potential of tDCS, and also affects the safety considerations.

► It is theoretically possible that tDCS stimulates glial cells instead of neurons.
► Calculations indicate that transmembrane potential change is of similar magnitude as observed physiologically in astrocytes during neuronal activation.
► Possibility to stimulate non-invasely glial cells would be a great therapeutic breakthrough.