Examining early spatial selection through a novel brightness illusion: Voluntary attention shapes the early selection of information.

摘要

Introduction: Recent behavioral work showed that internal cognitive factors played a role in regulating brightness perception, suggesting that higher order regions may modulate early visual activations through early attentional selection. A recently developed visual illusion (Tse, Vision Research, 2005) provides a strong example of a circumstance under which spatial attention influences perceived brightness in a "consciously perceptible" and "voluntarily manipulable" manner, providing an excellent means to assess the neural mechanisms of early attentional selection. We predicted that early visual evoked potentials would be enhanced for attended stimuli in this study, which would provide a compelling neural correlate for early attentional selection. Methods: Twenty-eight neurologically typical participants were included in this study. High-density EEG and eye-tracking were recorded. In each trial, participants selected a circular surface in the illusion that they would covertly attend. Subsequently, a sinusoidal grating appeared in one of the circles, and participants responded whether or not they detected a target (white ring in the grating). Early visual components (C1 and P1) were analyzed using Field-Trip. Results: For d-prime, a main effect of attention (p =.001) and a stimulus location x attention interaction (p = .005) were found. For reaction times, a main effect of attention (p =.000) and a stimulus location x attention interaction (p = .024) were observed. For the EEG data, a main effect of attention was found for the C1, (p = .047), but only in upper stimulus locations. For the P1, main effects of stimulus location (p = .000) and attention (p = .028) were observed. Conclusions: These findings revealed that voluntary attention modulated behavior and early visual evoked potentials, and these effects differed based on the spatial location of stimuli. These results suggest that voluntary, self-directed attention influences the early selection of information in hierarchically early visual cortices.