Adamian, N and Andersen, SK (2022) Attentional Enhancement of Tracked Stimuli in Early Visual Cortex Has Limited Capacity. Journal of Neuroscience, 42 (46). pp. 8709-8715. ISSN 0270-6474

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Abstract

Keeping track of the location of multiple moving objects is one of the well documented functions of visual attention. However, the mechanism of attentional selection that supports such continuous tracking is unclear. In particular, it has been proposed that target selection in early visual cortex occurs in parallel, with tracking errors arising because of attentional limitations at later processing stages. Here, we examine whether, instead, total attentional capacity for enhancement of early visual processing of tracked targets is shared between all attended stimuli. If the magnitude of attentional facilitation of multiple tracked targets was a key limiting factor of tracking ability, then one should expect it to drop systematically with increasing set-size of tracked targets. Human observers (male and female) were instructed to track two, four, or six moving objects among a pool of identical distractors. Steady-state visual evoked potentials (SSVEPs) recorded during the tracking period revealed that the processing of tracked targets was consistently amplified compared with the processing of the distractors. The magnitude of this amplification decreased with increasing set size, and at lateral occipital electrodes it closely followed inverse proportionality to the number of tracked items, suggesting that limited attentional resources must be shared among the tracked stimuli. Accordingly, the magnitude of attentional facilitation predicted the behavioral outcome at the end of the trial. Together, these findings demonstrate that the limitations of multiple object tracking (MOT) across set-sizes stem from the limitations of top-down selective attention already at the early stages of visual processing.

Item Type:	Article
Uncontrolled Keywords:	Visual Cortex; Humans; Photic Stimulation; Visual Perception; Motion Perception; Evoked Potentials, Visual; Visual Fields; Female; Male; EEG; attention; frequency tagging; multiple object tracking; spatial attention; steady-state visual evoked potentials; Male; Female; Humans; Evoked Potentials, Visual; Motion Perception; Visual Perception; Visual Fields; Visual Cortex; Photic Stimulation; 11 Medical and Health Sciences; 17 Psychology and Cognitive Sciences; Neurology & Neurosurgery
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Divisions:	Psychology (from Sep 2019)
Publisher:	Society for Neuroscience
SWORD Depositor:	A Symplectic
Date Deposited:	23 Jul 2024 13:52
Last Modified:	23 Jul 2024 13:52
DOI or ID number:	10.1523/JNEUROSCI.0605-22.2022
URI:	https://researchonline.ljmu.ac.uk/id/eprint/23787

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