A brain slice from a Parkinson’s sufferer

Hands-on research

Researchers can alter your brain function

Some techniques enable researchers to alter activity in the living human brain. One of these is transcranial magnetic stimulation (TMS), which uses a figure-of-eight-shaped coil placed on the scalp to deliver magnetic pulses to parts of the brain directly under the coil. This can be used in the lab to interrupt brain activity, to see how different brain regions contribute to certain functions. In the clinic, TMS can also be used to assess brain damage in people who have suffered a stroke and to aid their rehabilitation.

Transcranial electrical stimulation (tES) is a non-invasive, painless procedure which involves applying weak electrical currents to the head for a few minutes at a time via a pair of electrodes. There are a few different forms of tES, each utilising a different form of electrical current: transcranial direct current stimulaton (tDCS), transcranial random noise stimulation (tRNS) and transcranial alternating current stimulation (tACS).

tDCS is the most utilised method. It works by causing neurons to alter their firing rates by interfering with their own action potential production. Research on tDCS suggests that it could be effective in the treatment of a number of neurological disorders, including chronic pain, Parkinson’s disease, motor disorders and epilepsy. In this sense it is similar to TMS. There is also evidence that it can improve certain problems after a stroke and even alleviate some symptoms of Alzheimer’s. Some companies have created mechanisms for performing tES on your own at home, stating that it can improve normal cognitive function and performance. However, the mechanisms behind the effects of tES are still generally unknown and there is little scientific consensus about its use in daily life.

Deep brain stimulation is an invasive surgical procedure in which thin wire electrodes are implanted into the brain. By passing current through the wires from a control box outside the head, you can alter the activity of the region where the wires are implanted. Deep brain stimulation can help alleviate some symptoms of Parkinson’s disease, and so far it has been used to treat about 90,000 patients with the condition. It is also being used to treat other conditions, such as depression and obsessive–compulsive disorder, as well as drug addiction.

Lead image:

A brain slice from a Parkinson’s sufferer showing the depigmentation of the substantia nigra. Parkinson’s is one of the diseases that deep brain stimulation may be able to help treat.

UIC Department of Neurosurgery/Flickr CC BY NC ND


About this resource

This resource was first published in ‘Inside the Brain’ in January 2013 and reviewed and updated in November 2017.

Neuroscience, Psychology
Inside the Brain
Education levels:
16–19, Continuing professional development