Visual evoked potential evidence for parallel processing of depth- and form-related information in human visual cortex

1996 ◽  
Vol 111 (1) ◽  
Author(s):  
D.Aled Jeffreys
Keyword(s):  
Visual Cortex ◽  
Parallel Processing ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Human Visual Cortex ◽  
Related Information ◽  
Visual Evoked

scholarly journals Cortical Double-Opponent Cells in Color Perception: Perceptual Scaling and Chromatic Visual Evoked Potentials

i-Perception ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 204166951775271 ◽  
Author(s):  
Valerie Nunez ◽  
Robert M. Shapley ◽  
James Gordon
Keyword(s):  
Visual Cortex ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Color Perception ◽  
Neural Substrates ◽  
Response Dynamics ◽  
Early Visual Cortex ◽  
Visual Evoked

In the early visual cortex V1, there are currently only two known neural substrates for color perception: single-opponent and double-opponent cells. Our aim was to explore the relative contributions of these neurons to color perception. We measured the perceptual scaling of color saturation for equiluminant color checkerboard patterns (designed to stimulate double-opponent neurons preferentially) and uniformly colored squares (designed to stimulate only single-opponent neurons) at several cone contrasts. The spatially integrative responses of single-opponent neurons would produce the same response magnitude for checkerboards as for uniform squares of the same space-averaged cone contrast. However, perceived saturation of color checkerboards was higher than for the corresponding squares. The perceptual results therefore imply that double-opponent cells are involved in color perception of patterns. We also measured the chromatic visual evoked potential (cVEP) produced by the same stimuli; checkerboard cVEPs were much larger than those for corresponding squares, implying that double-opponent cells also contribute to the cVEP response. The total Fourier power of the cVEP grew sublinearly with cone contrast. However, the 6-Hz Fourier component’s power grew linearly with contrast-like saturation perception. This may also indicate that cortical coding of color depends on response dynamics.

scholarly journals Affective Bias without Hemispheric Competition: Evidence for Independent Processing Resources in Each Cortical Hemisphere

2020 ◽  
Vol 32 (5) ◽  
pp. 963-976
Author(s):  
Valeria Bekhtereva ◽  
Matt Craddock ◽  
Matthias M. Müller
Keyword(s):  
Visual Cortex ◽  
Steady State ◽  
Visual Field ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Low Level ◽  
Visual Hemifield ◽  
Early Visual Cortex ◽  
Processing Resources ◽  
Visual Evoked

We assessed the extent of neural competition for attentional processing resources in early visual cortex between foveally presented task stimuli and peripheral emotional distracter images. Task-relevant and distracting stimuli were shown in rapid serial visual presentation (RSVP) streams to elicit the steady-state visual evoked potential, which serves as an electrophysiological marker of attentional resource allocation in early visual cortex. A task-related RSVP stream of symbolic letters was presented centrally at 15 Hz while distracting RSVP streams were displayed at 4 or 6 Hz in the left and right visual hemifields. These image streams always had neutral content in one visual field and would unpredictably switch from neutral to unpleasant content in the opposite visual field. We found that the steady-state visual evoked potential amplitude was consistently modulated as a function of change in emotional valence in peripheral RSVPs, indicating sensory gain in response to distracting affective content. Importantly, the facilitated processing for emotional content shown in one visual hemifield was not paralleled by any perceptual costs in response to the task-related processing in the center or the neutral image stream in the other visual hemifield. Together, our data provide further evidence for sustained sensory facilitation in favor of emotional distracters. Furthermore, these results are in line with previous reports of a “different hemifield advantage” with low-level visual stimuli and are suggestive of independent processing resources in each cortical hemisphere that operate beyond low-level visual cues, that is, with complex images that impact early stages of visual processing via reentrant feedback loops from higher order processing areas.

The surface area of early visual cortex predicts the amplitude of the visual evoked potential

2014 ◽  
Vol 220 (2) ◽  
pp. 1229-1236 ◽  
Author(s):  
Torbjørn Elvsåshagen ◽  
Torgeir Moberget ◽  
Erlend Bøen ◽  
Per K. Hol ◽  
Ulrik F. Malt ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Surface Area ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Early Visual Cortex ◽  
Visual Evoked

Olfactory Modulation of Steady- State Visual Evoked Potential Topography in Comparison with Differences in Odor Sensitivity

2002 ◽  
Vol 16 (2) ◽  
pp. 71-81 ◽  
Author(s):  
Caroline M. Owen ◽  
John Patterson ◽  
Richard B. Silberstein
Keyword(s):  
Steady State ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Behavioral Responses ◽  
Simultaneous Recording ◽  
Odor Concentration ◽  
Odor Detection ◽  
Detection Response ◽  
Response Groups ◽  
Visual Evoked

Summary Research was undertaken to determine whether olfactory stimulation can alter steady-state visual evoked potential (SSVEP) topography. Odor-air and air-only stimuli were used to determine whether the SSVEP would be altered when odor was present. Comparisons were also made of the topographic activation associated with air and odor stimulation, with the view toward determining whether the revealed topographic activity would differentiate levels of olfactory sensitivity by clearly identifying supra- and subthreshold odor responses. Using a continuous respiration olfactometer (CRO) to precisely deliver an odor or air stimulus synchronously with the natural respiration, air or odor (n-butanol) was randomly delivered into the inspiratory airstream during the simultaneous recording of SSVEPs and subjective behavioral responses. Subjects were placed in groups based on subjective odor detection response: “yes” and “no” detection groups. In comparison to air, SSVEP topography revealed cortical changes in response to odor stimulation for both response groups, with topographic changes evident for those unable to perceive the odor, showing the presence of a subconscious physiological odor detection response. Differences in regional SSVEP topography were shown for those who reported smelling the odor compared with those who remained unaware of the odor. These changes revealed olfactory modulation of SSVEP topography related to odor awareness and sensitivity and therefore odor concentration relative to thresholds.

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