Authors:

Duncan, J., Humphreys, G. & Ward, R.

Reference:

Year of publication:

1997

CBU number:

3474

Abstract:

This article considers the problem of visual attention from the perspective of distributed brain activity engendered by visual input. We propose that objects in the visual environment compete for representation in multiple brain systems, sensory and motor, cortical and subcortical. Competition is integrated, however, such that multiple systems converge, working on the different properties of a selected object and its different implications for action. Top-down priming biases competition towards objects relevant to current behaviour. Single unit studies are reviewed to show widespread suppression of ignored-object representations in extrastriate cortex, and distinct pattern of task-specific priming or sustained cellular activity. Human and monkey lesion studies show the strong tendency of different spatial systems to integrate, a tendency also shown in studies of normal behaviour. Both the extent of integration and its limitations are considered. According to our view, no specific brain system is responsible for higher cognitive activities such as attention. Unified function emerges from the tendency of distinct systems to work together on common cognitive problems.