Neural correlates of attention in primate visual cortex

The processing of visual information combines bottom-up sensory aspects wit h top-down influences, most notably attentional processes. Attentional infl uences have now been demonstrated throughout visual cortex, and their influ ence on the processing of visual information is profound. Neuronal response s to attended locations or stimulus features are enhanced, whereas those fr om unattended locations or features are suppressed. This influence of atten tion increases as one ascends the hierarchy of visual areas in primate cort ex, ultimately resulting in a neural representation of the visual world tha t is dominated by the behavioral relevance of the information, rather than designed to provide an accurate and complete description of it. This realiz ation has led to a rethinking of the role of areas that have previously bee n considered to be 'purely sensory'.