The timing of feature-based attentional effects during object perception

Department of Psychology, University of Toronto at Scarborough, Toronto, Ontario, Canada.
Neuropsychologia (Impact Factor: 3.3). 08/2011; 49(12):3406-18. DOI: 10.1016/j.neuropsychologia.2011.08.017
Source: PubMed


Allocating attention to basic features such as colour enhances perception of the respective features throughout the visual field. We have previously shown that feature-based attention also plays a role for more complex features required for object perception. To investigate at which level object perception is modulated by feature-based attention we recorded high-density event-related potentials (ERPs). Participants detected contour-defined objects or motion, and were informed to expect each feature dimension. Participants perceived contour-defined objects and motion better when they expected the congruent feature. This is consistent with modulation of the P1 when attending to lower-level features. For contours, modulation occurred at 290 ms, first at frontal electrodes and then at posterior sites, associated with sources in ventral visual areas accompanied by greater signal strength. This pattern of results is consistent with what has been observed in response to illusory contours. Our data provide novel insights into the contribution of feature-based attention to object perception that are associated with higher tier brain areas.

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Available from: Bobby (Boge) Stojanoski, Mar 11, 2014
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    • "The difference in feature-based attention is arguably seen in the small HI/LO effect during the late P1 phase, likely because the lower spatial frequencies were less salient (Singh et al., 2011) and required more attentional effort. An influence of feature-based attention is consistent with the timing of the effect (Stojanoski & Niemeier, 2011; Zhang & Luck, 2009) and with source localization, estimating that the effect originated from the dorsal parietal cortex (Liu, Hospadaruk, Zhu, & Gardner, 2011). It showed a trend of left-sided activation, perhaps due to a task-specific larger P1 amplitude and better signal-to-noise ratio on the left. "
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