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. Author manuscript; available in PMC: 2009 Nov 16.
Published in final edited form as: Biol Psychiatry. 2009 Apr 1;65(7):548–549. doi: 10.1016/j.biopsych.2009.01.022

Figure 1.

Figure 1

Illustration of the race model for the stop-signal task and the effect of atomoxetine proposed in Chamberlain et al. The race model includes a GO process (green) and a STOP process (red) that are racing independently toward a common threshold. The GO stimulus onset is at time 0 (green arrow), triggering a rise in the GO process (green) after a delay. The stop stimulus onset is at 200 msec (red arrow), triggering a rise in the STOP process (red) after a delay. If the GO process reaches threshold first (upper panel), then a response is generated (non-cancelled trials). Conversely, if the STOP process finishes before the GO process (lower panel), then the response is cancelled. Functional magnetic resonance imaging studies show relatively higher activation of the right inferior frontal gyrus (RIFG) on cancelled trials. Atomoxetine decreases stop-signal reaction times and increases RIFG activation on cancelled trials, possibly by increasing the strength (rate of rise) of the Stop process. Modified with permission from Hanes et al. (6).