Attentional Modulation of Apparent Stimulus Contrast

Abstract

Voluntary attention modulates sensory processing in the visual system of primates by multiplying the response of neurons to attended/unattended stimuli. This effect resembles the modulation of neuronal responses caused by varying stimulus contrast. Additionally, attentional and contrast modulation of neuronal responses in monkey cortical area MT share a nonlinearity. Neuronal responses are more strongly modulated by attention and contrast changes for intermediate contrast stimuli than for low and high contrast stimuli. These similarities between attention and contrast suggests that they use similar or closely related mechanisms to modulate visual processing in the cortex.