Consciousness and attention

This article addresses the relationship between attention and consciousness. I take consciousness to refer, at least in an approximate sense, to those thoughts, memories, sensations, and actions of which one is aware, whereas attention refers to those processes that modulate neuronal activity. This modulation may be achieved by virtue of linking or binding distinct neuronal populations or by selecting information for further processing. Thus, consciousness and attention are different but closely related in that attention provides the glue that binds processes and representations to the prevailing cognitive set, thereby rendering them conscious. In this context, then, attention may be viewed as a control process. A number of neurologic syndromes in which disorders of attention result in the fragmentation of consciousness are discussed. Finally, the anatomic bases of attention, both cortical and subcortical, are reviewed.