What is tDCS
The basic idea of tDCS or Transcranial Direct Current Stimulation to stimulate an area of interest in the brain, has been around for over 100 years. Unfortunately, the discovery did not receive much attention. When electroshock therapy was developed in the 1930s and was found to be a relatively effective treatment against depression, tDCS was completely abandoned. There was a brief rise of interest in tDCS in the 1960's but more recently with the advent of new brain imaging techniques such as MRI and fMRI, which have led to a better understanding of basic brain functioning, tDCS is finally at the center of attention.
During a treatment session, the tDCS machine uses a small electric current (very unlike electroshock therapy). Electrodes (sponges soaked in salt water) are placed over certain parts of the head. The electrodes are held in place using a rubber headband. The direct current flows through the electrodes, penetrating the scalp, creating a flow of electrical current in the brain. Usually a slight itching or tingling sensation can be felt on the scalp. The weak currents enhance brain activity under the site of the electrodes.
tDCS differs from other brain stimulation techniques such as transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS), by not inducing neuronal action potentials. This contributes to the safety of tDCS.