Robust sensory gating in the cortical visual evoked potential using two spatially separated stimuli.
OBJECTIVE
Sensory gating has been reported to be either absent or weak in the cortical visual evoked potential (VEP) response to diffuse or spatially overlapping stimuli. In this study, the authors evaluated sensory gating to two spatially separated visual stimuli.


METHODS
Spatially separated stimuli were presented either singly or in combination at the same or different onset times and the VEP recorded at either Oz, or O1 and O2, referenced to Cz.


RESULTS
When one visual stimulus is flashed on, the VEP response to another non-overlapping stimulus is almost completely suppressed.


CONCLUSIONS
The VEP does not reflect the bulk activation of retinotopically organized visual cortex, but rather it primarily reflects a distributed mode of visual cortical activity that only indicates that at least one visual stimulus was presented, and not how many or in what order.


CONCLUSIONS
Other studies performing intracortical recordings of the local field potential (LFP) in visual cortex have identified a slow-distributed component that exhibits the same nonlinearity found here in the VEP, suggesting that these two phenomena are related.
Gawne
Timothy J
TJ
University of Alabama at Birmingham (UAB), 924 South 18th St., Birmingham, AL 35294, United States. Electronic address: tgawne@gmail.com.
Osbourne
Tiana S
TS
Oakwood University, 7000 Adventist Blvd. NW, Huntsville, AL 35896, United States.
Risner
Michael L
ML
University of Alabama at Birmingham (UAB), 924 South 18th St., Birmingham, AL 35294, United States.
D000328:Adult; D001767:Blinking / Q000502:physiology; D004569:Electroencephalography; D004585:Electrooculography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D010775:Photic Stimulation; D055139:Sensory Gating / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult