In one groundbreaking study, investigators have for the first time measured the number of neurons in a particular area of the basal ganglia-the brain area involved in Tourette's-in patients with the disorder. Other studies suggest an imbalance in the basal ganglia's inhibitory function could interfere with its ability to suppress unwanted movements and vocalizations and thus lead to Tourette's syndrome.

One of the least understood brain disorders, Tourette's syndrome affects about one in 200 children. Symptoms usually appear between the ages of four and eight and include repetitive involuntary movements and utterances, or "tics." Tics vary according to where, how often, and how strongly they are expressed. They are often preceded by a sensory cue or "urge to tic" that can besiege the individual's consciousness. Tics wax and wane in severity and are typically worse during periods of emotional stress or fatigue.

Although many children experience their worst symptoms around the age of 10 or 11 and then improve, some patients show their worst symptoms as adults. In its most extreme form, the tics can be virtually nonstop and include "purposive"-appearing repetitive behaviors including obscene or socially inappropriate speech and more rarely self-injurious behaviors. In addition to tics, individuals with Tourette's also often have obsessions, compulsions, and attentional deficits.

Scientists now know that symptoms of Tourette's syndrome likely arise from dysfunction in a region deep within the brain called the basal ganglia. Neurons in the basal ganglia inhibit or initiate action plans by processing the information they receive from the "executive centers" in the brain's prefrontal cortex and sending it back to motor and sensory areas of the cortex through the
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Contact: Leah Arinello
dawn@sfn.org
202-462-6688
Society for Neuroscience
24-Oct-2004