The studies reported in this chapter argue for a flexible organization of higher mental processes, including perceptual and attentional systems in the visual modality and attentional systems related to action. There is electrophysiologic evidence that the visual perceptual system has a modularized structure, and that selection of perceived features is adjustable to sensory, conceptual, and utility constraints, both with respect to the hierarchy of selection cues and the transmission of information between perception and action. A distributed neural network subserves these functions and may therefore provide a source for plasticity and reorganization after brain damage by flexibility in the allocation of resources to various stages of stimulus analysis.