The basal ganglia are a group of specialised brain cells located deep inside the brain. The cells help regulate the body’s movements.
Research suggests the basal ganglia may also play a role in higher brain functions such as motivation and decision making. In people with Tourette Syndrome, it appears tics are the result of a temporary problem occurring within the basal ganglia which disrupts the decision-making process. The person suddenly develops an unconscious urge to perform an action (the tic) that the conscious mind regards as both unwanted and unexplained.
It’s not known what actually goes wrong with the basal ganglia. One theory suggests excessive levels of a naturally occurring chemical called dopamine, which can have powerful effects on the brain, could be responsible.
Alternatively, the dopamine levels could be normal in people with Tourette Syndrome, but they may be particularly sensitive to its effects.
Brain imaging studies have also shown the structure of the basal ganglia is different in people with Tourette Syndrome. However, it is unclear whether these changes are due to a dopamine imbalance or sensitivity, or the cause of it.