Scientists are not sure what causes Tourette syndrome and many other brain disorders. We know that it is inherited in the majority of cases. But we don't know the exact mode of inheritance, and scientists have not yet found a specific Tourette's gene. What they can seem to agree on is that the tics of Tourette syndrome result from abnormalities in the brain. Specifically, they have pinpointed dysfunctions in the thalamus, basal ganglia and frontal cortex of the brain, as well as dysfunctions in the neurotransmitters between the brain's nerve cells.
Scientists suspect these parts of the brain because of their roles in brain function. The thalamus works to relay sensory and motor information to the cerebral cortex and the brain stem. The basal ganglia is located at the base of the brain and works in the coordination of motor movements. Therefore, disorders of the basal ganglia usually result in a patient whose movements are unintentional and occur unexpectedly. The frontal cortex is located, as the name suggests, in the front of the brain, directly behind the forehead. This part of the brain is in charge of controlling skilled motor activity, which includes speech.
Abnormalities in the neurotransmitters -- specifically, excessive amounts of the neurotransmitter dopamine -- may be involved in the syndrome as well, with some suggesting that it could be the underlying mechanism of Tourette's. Dopamine works in the brain to help regulate normal movement and emotions. Therefore, any disruption can change these factors. Decreased levels of dopamine have been a suggested cause of Parkinson's disease, an affliction that is characterized by slow movements, facial paralysis and overall weakness. In patients with excessive amounts of dopamine, sudden, spasmodic, involuntary muscular contractions, like those found in Tourette's, would be expected.
Now let's find out about the many different symptoms of Tourette syndrome.