Transcranial direct current stimulation (tDCS) is a form of neuromodulation that uses constant, low direct current delivered via electrodes on the head. It was originally developed to help patients with brain injuries or neuropsychiatric conditions such as major depressive disorder.
Popularity in recent years
tDCS has become a popular brain stimulation method that is used to modulate cortical excitability, producing facilitatory or inhibitory effects upon a variety of behaviors. tDCS is popular because it is non-invasive, non-pharmaceutical and when done by trained professionals produces fast results. Below excerpts taken from an article published by Thair, Holloway, Newport and Smith in 2017.
Why use tDCS?
tDCS is a non-invasive method, allowing for the reversible modulation of activity in particular brain regions. This has provided a valuable tool for establishing brain-behaviour relationships across a variety of cognitive, motor, social, and affective domains (for a review see Filmer et al., 2014) and, in healthy populations, it has been shown to temporarily modify behaviour, accelerate learning, and boost task performance (Coffman et al., 2014; Parasuraman and McKinley, 2014).
For example, anodal stimulation has been shown to enhance facial expression recognition (Willis et al., 2015) or inhibit aggressive responses (Dambacher et al., 2015; Riva et al., 2015), whereas cathodal stimulation has been shown to foster implicit motor learning when stimulating the dorsolateral prefrontal cortex by suppressing working memory activity (Zhu et al., 2015). Findings suggest this form of electric stimulation could make you better at math, more creative and even boost memory.
Indeed, tDCS has even been successfully applied to reduce symptoms of depression (Fregni et al., 2006; Nitsche et al., 2009), although the field needs to expand further to support its use for this purpose. In small-scale studies it has been shown to reduce hallucinations in people with schizophrenia (Agarwal et al., 2013) and to improve delays of syntax acquisition in autism spectrum disorder (Schneider and Hopp, 2011).
There are no reported indications of any serious adverse effects with the use of 1–2 mA tDCS (Arul-Anandam et al., 2009).