Neural control of behavior: countermanding eye movements

Understanding the self-control of action entails knowledge about how actions are initiated, how planned actions are canceled and how the consequences of actions are registered. We have investigated neural correlates of these processes using the countermanding paradigm--a task that required subjects to occasionally cancel a planned speeded response, and an analysis that provides an estimate of the time needed to cancel a planned movement. By monitoring the activity of single neurons in the frontal cortex of macaque monkeys performing this task we have distinguished signals responding to the visual stimuli, other signals that control the production of movements, and still other signals that seem to monitor behavior.