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Updated: Jun 13, 2026
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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
From prestimulus alpha oscillation to visual-evoked response: an inverted-U function and its attentional modulation.
Rajasimhan Rajagovindan1, Mingzhou Ding
1University of Florida, Gainesville, FL 32611, USA.
Journal of Cognitive Neuroscience
|May 13, 2010
Summary
This study models how prestimulus neural activity, specifically background synaptic activity, influences brain responses to stimuli. Enhanced attention shifts neural excitability for improved stimulus processing and increased gain.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Human Visual Processing
Background:
- Prestimulus neural activity influences stimulus processing, but mechanisms in humans remain unclear.
- Existing EEG/MEG studies on prestimulus alpha oscillations and visual-evoked potentials lack consensus.
- Understanding background synaptic activity's role in cortical neuron responsiveness is crucial.
Purpose of the Study:
- To develop a theoretical model linking background synaptic activity to neural firing rate and stimulus-evoked responses.
- To extend this model to human visual processing using EEG and investigate attention's effects.
- To elucidate the relationship between neural excitability, attention, and visual processing gain.
Main Methods:
- Developed a computational model with a sigmoidal function relating background synaptic activity to neural firing rate, defining 'local gain'.
- Adapted the model for human EEG studies, reinterpreting variables in terms of oscillations and event-related potentials.
- Recorded high-density scalp EEG during a cued spatial visual attention task in healthy volunteers.
Main Results:
- The model predicted that local gain, the derivative of the sigmoidal function, is inverted-U shaped and proportional to trial-by-trial responses.
- Attention enhanced stimulus processing, correlating with an increased slope in the sigmoidal function.
- Reduced alpha magnitude during attention indicated a shift towards optimal neural excitability, increasing global gain.
Conclusions:
- Attention enhances visual stimulus processing by optimizing neural excitability and increasing overall gain, as modeled by a sigmoidal function.
- Prestimulus alpha oscillations may serve as an indicator of neural ensemble excitability state.
- The study provides a framework for understanding how background neural activity modulates sensory processing in humans.
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