Neural selection and control of visually guided eye movements

We review neural correlates of perceptual and motor decisions, examining wh ether the time they occupy explains the duration and variability of behavio ral reaction times. The location of a salient target is identified through a spariotemporal evolution of visually evoked activation throughout the vis ual system. Selection of the target leads to stochastic growth of movement- related activity toward a fixed threshold to generate the gaze shift. For a given image, the neural concomitants of perceptual processing occupy a rel atively constant interval so that stochastic variability in response genera tion introduces additional variability in reaction times.