Neural strength of visual attention gauged by motion adaptation

Single-cell and neuroimaging studies reveal that attention focused on a visual object markedly amplifies neural activity produced by features of the attended object. In a psychophysical study, we found that visual attention could modulate the strength of weak motion signals to the point that the perceived direction of motion, putatively registered early in visual processing, was powerfully altered. This strong influence of attention on early motion processing, beside complementing neurophysiological evidence for attentional modulation early in the visual pathway, can be measured in terms of equivalent motion energy, and thus provides a useful metric for quantifying attention's effects.