| Abstract: | To access the role of attention in visual processing, we have recorded single-unit activity from area V4 of visual cortex in macaque monkeys, and the results of these experiments provide a clear demonstration of the relationship between inter-stimulus competition and attention. Specifically, attended stimuli elicit larger responses than ignored stimuli, and these attention effects are increased when: a) the total number of distracting stimuli is increased; b) both attended and ignored stimuli are located inside the neuron's receptive field; and c) the attended and ignored stimuli are presented simultaneously rather than sequentially. We have also examined the role of inter-stimulus competition in human subjects by recording event-related potentials (ERPs), which are electrophysiological responses that can be recorded noninvasively from the scalp. In these experiments, we have found that the attention-sensitive N2pc wave is present when subjects focus attention onto target stimuli when they are surrounded by competing distractor stimuli, but is absent when the competition is eliminated (e.g. by removing the distractors). (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
