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Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
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Phasic modulation of visual representations during sustained attention
Mats W J van Es1,2, Tom R Marshall1,2, Eelke Spaak1
1Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
The European Journal of Neuroscience
|December 15, 2020
Summary
Sustained attention influences perception rhythmically, not continuously. Brain activity in specific attention networks, not visual cortex, modulates this effect, suggesting top-down attentional sampling.
Area of Science:
- Cognitive Neuroscience
- Neuroimaging
- Visual Perception
Background:
- Sustained attention traditionally viewed as continuous.
- Emerging evidence suggests attention operates discretely and rhythmically.
- Oscillatory brain activity (theta/alpha frequencies) linked to attentional sampling.
Purpose of the Study:
- Investigate if discrete attentional sampling is reflected in visual stimulus decodability from brain signals.
- Examine periodic fluctuations in decoding visual orientation based on brain activity phase.
- Determine the role of frontoparietal networks in attention-modulated perception.
Main Methods:
- Magnetoencephalography (MEG) recorded from human subjects attending to visual stimuli.
- Support Vector Machine (SVM) used to decode stimulus orientation (clockwise/counterclockwise) from MEG signals.
- Analysis of whether decoder performance depended on theta/alpha phase in specific brain regions.
Main Results:
- Decoding performance of visual stimulus orientation was modulated by theta/alpha phase.
- Modulation was observed in frontal eye fields and parietal cortex, contralateral to the attended stimulus.
- No modulation of decoding performance was found based on visual cortex activity phase.
Conclusions:
- Phasic modulations in visual stimulus representation are driven by frequency-specific top-down activity in the frontoparietal attention network.
- Suggests a rhythmic, top-down mechanism for attentional sampling in visual processing.
- Behavioral relevance of these observed neural effects remains to be established.
