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Neural and vascular responses to fused binocular stimuli: a VEP and fNIRS study.

Abstract

PURPOSE
The aim of our study was to investigate the correlation between neural and hemodynamic responses to stereoscopic stimuli recorded over visual cortex.
METHODS
Test stimuli consisted of a static checkerboard (checks) and dichoptic static random dot (RD) presentations with no binocular disparity (ZD) or with horizontal disparity (HD). Hemodynamic responses were recorded from right and left occipital sites using functional near-infrared spectroscopy (fNIRS). Visual evoked potentials (VEPs) were recorded over three occipital sites to the onset of the same stimuli.
RESULTS
Early components, N1 and P2, were sensitive to HD, suggesting that an enhanced N1-reduced P2 complex could be an indicator of binocular disparity and stereopsis. VEPs to checks and ZD stimulation were similar. fNIRS recordings showed changes in hemodynamic activation from baseline levels in response to all stimuli. In general, HD elicited a larger vascular response than ZD. Oxyhemoglobin concentration (HbO) was correlated with the VEP amplitude during the checks and HD presentations.
CONCLUSIONS
We report an association between neural and hemodynamic activation in response to checks and HD. In addition, the results suggested that N1-P2 complex in the VEP could be a neural marker for stereopsis and fNIRS demonstrated differences in HbO. Specifically, checks and HD elicited larger hemodynamic responses than random dot patterns without binocular disparity.

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  • Publisher Full Text

    • Authors

    Wijeakumar S, Shahani U, McCulloch DL, Simpson WA

    Institution

    Glasgow Caledonian University, Vision Sciences, Department of Life Sciences, Glasgow, United Kingdom. swijea11@gcal.ac.uk

    Source

    Investigative ophthalmology & visual science 53:9 2012 Aug pg 5881-9

    MeSH

    Adolescent
    Adult
    Analysis of Variance
    Evoked Potentials, Visual
    Female
    Hemodynamics
    Humans
    Male
    Oxyhemoglobins
    Photic Stimulation
    Spectroscopy, Near-Infrared
    Vision Disparity
    Vision, Binocular
    Visual Cortex
    Young Adult

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    22871839