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2015 ; 25
(4
): 1080-92
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Neural mechanisms of object-based attention
#MMPMID24217991
Cohen EH
; Tong F
Cereb Cortex
2015[Apr]; 25
(4
): 1080-92
PMID24217991
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What neural mechanisms underlie the ability to attend to a complex object in the
presence of competing overlapping stimuli? We evaluated whether object-based
attention might involve pattern-specific feedback to early visual areas to
selectively enhance the set of low-level features corresponding to the attended
object. Using fMRI and multivariate pattern analysis, we found that activity
patterns in early visual areas (V1-V4) are strongly biased in favor of the
attended object. Activity patterns evoked by single faces and single houses
reliably predicted which of the 2 overlapping stimulus types was being attended
with high accuracy (80-90% correct). Superior knowledge of upright objects led to
improved attentional selection in early areas. Across individual blocks, the
strength of the attentional bias signal in early visual areas was highly
predictive of the modulations found in high-level object areas, implying that
pattern-specific attentional filtering at early sites can determine the quality
of object-specific signals that reach higher level visual areas. Through
computational modeling, we show how feedback of an average template to V1-like
units can improve discrimination of exemplars belonging to the attended category.
Our findings provide a mechanistic account of how feedback to early visual areas
can contribute to the attentional selection of complex objects.
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