# Show Reference: "Attentional Modulation of Visual Processing"

Attentional Modulation of Visual Processing Annual Review of Neuroscience, Vol. 27, No. 1. (2004), pp. 611-647, doi:10.1146/annurev.neuro.26.041002.131039 by John H. Reynolds, Leonardo Chelazzi
@article{reynolds-and-chelazzi-2004,
abstract = {▪ Abstract Single-unit recording studies in the macaque have carefully documented the modulatory effects of attention on the response properties of visual cortical neurons. Attention produces qualitatively different effects on firing rate, depending on whether a stimulus appears alone or accompanied by distracters. Studies of contrast gain control in anesthetized mammals have found parallel patterns of results when the luminance contrast of a stimulus increases. This finding suggests that attention has co-opted the circuits that mediate contrast gain control and that it operates by increasing the effective contrast of the attended stimulus. Consistent with this idea, microstimulation of the frontal eye fields, one of several areas that control the allocation of spatial attention, induces spatially local increases in sensitivity both at the behavioral level and among neurons in area V4, where endogenously generated attention increases contrast sensitivity. Studies in the slice have begun to explain how modulatory signals might cause such increases in sensitivity.},
address = {Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037-1099, USA. reynolds@salk.edu},
author = {Reynolds, John H. and Chelazzi, Leonardo},
citeulike-article-id = {345511},
doi = {10.1146/annurev.neuro.26.041002.131039},
issn = {0147-006X},
journal = {Annual Review of Neuroscience},
keywords = {attention, biology, cortex, visual},
number = {1},
pages = {611--647},
pmid = {15217345},
posted-at = {2014-06-06 10:47:29},
priority = {2},
title = {Attentional Modulation of Visual Processing},
url = {http://dx.doi.org/10.1146/annurev.neuro.26.041002.131039},
volume = {27},
year = {2004}
}



Feature-based visual attention facilitates object detection across the visual field.

Spatial visual attention increases the activity of neurons in the visual cortex whose receptive fields overlap the attended region.

Visual spatial attention

• lowers the stimulus detection threshold,
• improves stimulus discrimination,

With two stimuli in the receptive field, one with features of a visual search target and one with different features

• increases average neural activity in cortex compared to the same two objects without attending to any features
• decreases average neural activity if spatial attention is on the location of the non-target compared to when it is on the target.

The fact that average neural activity in cortex is decreased if spatial attention is on the location of a non-target out of a target and a non-target compared to when it is on the target supports the notion that inhibition plays an important role in stimulus selection.

Two superimposed visual stimuli of different orientation, one optimal for a given simple cell in visual cortex, the other sub-optimal but excitatory, can elicit a weaker response than just the optimal stimulus.