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Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping
Published on: June 26, 2012
Electrocorticography links human temporoparietal junction to visual perception
Michael S Beauchamp1, Ping Sun, Sarah H Baum
1Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, Texas, USA. michael.s.beauchamp@uth.tmc.edu
Nature Neuroscience
|June 5, 2012
Summary
Electrical stimulation of the visual cortex creates phosphenes only when it triggers high-frequency gamma oscillations in the temporoparietal junction (TPJ). This brain region is linked to visual neglect and influences stimulus detection.
Area of Science:
- Neuroscience
- Visual Perception
- Electrophysiology
Background:
- Electrical stimulation of the visual cortex can elicit phosphenes, which are visual perceptions.
- The temporoparietal junction (TPJ) is implicated in visual extinction and neglect.
Purpose of the Study:
- To investigate the relationship between electrical stimulation of the visual cortex, phosphene perception, and neural activity in the temporoparietal junction (TPJ).
- To determine if TPJ activity is necessary for phosphene generation and if TPJ stimulation affects visual stimulus detection.
Main Methods:
- Subdural electrodes were implanted in humans to stimulate the visual cortex.
- Simultaneous electrophysiological recordings were made from other brain sites, including the TPJ.
- The detectability of low-contrast visual stimuli was assessed before and after TPJ electrical stimulation.
Main Results:
- Phosphene perception was consistently associated with the evocation of high-frequency gamma oscillations in the TPJ.
- Electrical stimulation of the TPJ altered the detectability of low-contrast visual stimuli, suggesting its role in visual processing.
- Gamma oscillations in the TPJ appear to be a critical correlate of visually evoked percepts.
Conclusions:
- High-frequency gamma oscillations in the TPJ are necessary for the perception of phosphenes induced by visual cortex stimulation.
- The TPJ plays a crucial role in modulating visual awareness and the detection of visual stimuli.
- These findings link direct cortical stimulation effects to specific network dynamics in higher-order visual areas.
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