Neural selection and control of visually guided eye movements.

We review neural correlates of perceptual and motor decisions, examining whether the time they occupy explains the duration and variability of behavioral reaction times. The location of a salient target is identified through a spatiotemporal evolution of visually evoked activation throughout the visual 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 relatively constant interval so that stochastic variability in response generation introduces additional variability in reaction times.