I recently ran into a website making some pretty interesting claims about "transcranial Direct Current Stimulation (tDCS)". The claims are as follows:
Overclock your brain using transcranial Direct Current Stimulation (tDCS) to increase the plasticity of your brain. Make your synapses fire faster.
While this seemed to be to be pretty obvious snake-oil pitch, I was curious as to whether there was any scientific basis for the claims made. There is a Wikipedia entry for Transcranial direct-current stimulation, indicating that it is "form of neurostimulation originally developed to help patients with brain injuries such as strokes." It also makes similar claims of beneficial effects in the article's initial summary, but they don't seem to be appropriately referenced:
Tests on healthy adults demonstrated that tDCS can increase cognitive performance on a variety of tasks , depending on the area of the brain being stimulated. tDCS has been utilized to enhance language and mathematical ability, attention span, problem solving, memory, and coordination.
While I haven't conducted a thorough review of every scientific article referenced, most seem to relate to treatment of brain disorders rather than any effects on a healthy adult brain.
Is there any scientifically verifiable evidence that passing an electrical current across certain parts of a healthy person's brain can either a) increase the plasticity of the brain, b) make synapses fire faster, or c) otherwise improve a person's cognitive ability.