Motor response inhibition in children with Tourette's disorder.

Tourette's disorder has long been regarded as a disorder of involuntary movement. Here the authors show that children with Tourette's disorder do not differ from healthy comparison subjects in stop-signal inhibition. These results suggest the importance of considering motor tics as voluntary rather than as involuntary.

Attentional blink in adolescents with varying levels of impulsivity.

We explore the temporal attention function in a non-clinical sample of adolescents varying in impulsivity, as assessed with the Barratt Impulsiveness Scale. In a Rapid Serial Visual Presentation task, in which two targets (T(1) and T(2)) were presented in close temporal proximity among distractors, participants tried to identify T(1) and detect T(2) in one (dual-task) experiment and only to detect T(2) in a second, control (single-task) experiment. The sensitivity of T(2) detection was analyzed using signal detection theory. The attentional blink -- the impairment in T(2) detection following the identification of T(1) -- was increased in magnitude and protracted in adolescents with high impulsivity, compared with those with low impulsivity. Moreover, a few more participants with high impulsivity appeared to have a blink temporally weighing toward a later time, an observation also made in children with attention deficit hyperactivity disorder (ADHD) in an earlier study. Taken together, these findings suggest impairment in temporal attention in adolescents with high impulsivity. As in ADHD children, a gating deficit may play a central role in this attention impairment.