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Updated: Jun 13, 2026
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Extracting Visual Evoked Potentials from EEG Data Recorded During fMRI-guided Transcranial Magnetic Stimulation
Published on: May 12, 2014
Combining steady-state visual evoked potentials and f MRI to localize brain activity during selective attention
S A Hillyard1, H Hinrichs, C Tempelmann
1Department of Neurosciences, University of California, San Diego, La Jolla, California 92093, USA. shillyard@ucsd.edu
Human Brain Mapping
|April 22, 2010
Summary
Attention enhances brain activity in visual processing areas. Focusing attention on visual stimuli increases steady-state visual evoked potentials (SSVEPs) amplitude, localized to extrastriate cortex using fMRI.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Visual Perception
Background:
- Understanding how attention modulates neural activity is crucial for cognitive neuroscience.
- Previous research suggests attention influences visual processing, but precise localization remains an area of investigation.
- Employing multimodal neuroimaging techniques can provide a more comprehensive understanding of attentional mechanisms.
Purpose of the Study:
- To investigate the neural correlates of visual attention using functional magnetic resonance imaging (fMRI) and steady-state visual evoked potentials (SSVEPs).
- To determine if attentional focus modulates the amplitude of SSVEPs.
- To localize the brain regions responsible for attentional modulation within the visual cortex.
Main Methods:
- Subjects performed an attention task involving letter sequences presented in either the left or right visual field.
- Brain activity was measured using fMRI and SSVEPs elicited by flickering backgrounds (8.6 Hz and 12.0 Hz).
- Source analysis of SSVEP waveforms was performed to pinpoint the origin of the attentional modulation.
Main Results:
- The amplitude of frequency-coded SSVEPs was significantly larger when attention was directed to the attended visual field.
- fMRI data revealed activation in specific visual cortex regions.
- Source analysis of SSVEPs localized attentional modulation to ventral and lateral extrastriate visual cortex, consistent with fMRI findings.
Conclusions:
- Attentional focus enhances neural processing in specific visual cortical areas.
- SSVEPs, modulated by attention, provide a reliable measure of visual processing.
- The findings demonstrate the convergence of fMRI and SSVEP source analysis in mapping attentional networks in the extrastriate visual cortex.
