June 2004
Volume 4, Issue 8
Free
Vision Sciences Society Annual Meeting Abstract  |   August 2004
Dipole source modelling of the magnetoencephalogram to stereopsis, binocular fusion and rivalry.
Author Affiliations
  • David C. Mansfield
    Department of Vision Sciences Glasgow Caledonian University, Glasgow, UK
  • Uma Shahani
    Department of Vision Sciences Glasgow Caledonian University, Glasgow, United Kingdom
  • Daphne L. McCulloch
    Department of Vision Sciences Glasgow Caledonian University, Glasgow, United Kingdom
  • William S. Simpson
    DRDC-Toronto, Canada
Journal of Vision August 2004, Vol.4, 601. doi:10.1167/4.8.601
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      David C. Mansfield, Uma Shahani, Daphne L. McCulloch, William S. Simpson; Dipole source modelling of the magnetoencephalogram to stereopsis, binocular fusion and rivalry.. Journal of Vision 2004;4(8):601. doi: 10.1167/4.8.601.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract
 

Purpose: To characterise magnetoencephalographic activity (MEG) during normal binocular fusion, binocular rivalry and stereopsis using red/green stereograms. Methods: Subjects viewed red/green random dot stereo pairs. A horizontal grating (0.2 cycles/degree) was detectable only when stereo-pairs contained horizontal disparity. Similar vertical disparity produced binocular rivalry. Zero disparity was the control condition for flat fusion. MEG signals were recorded from 9 normal subjects using a helmet-shaped 306-channel detector array, and band-passed from 0.03 to 200 Hz with a sampling rate of 600 Hz excluding blink artefacts. Visually evoked fields (VEFs) time-locked to each stimulus pair were modelled as equivalent current dipoles whose 3-D locations, orientations and strengths were found using signals from several sensors over the maximum response area. Results: Maximal activity in the VEF was present at about 150 ms and again between 250 and 300 ms. A 3-dipole model was developed consisting of left and right occipital dipoles and a single parietal dipole. This model accounted for over 80% of the MEG activity at the maxima. The maxima at 150 ms had contributions from all three dipoles. After 250 ms the activity could be represented by a single parietal dipole which was strongest during horizontal disparity and was weaker during vertical disparity. Conclusion: Stimuli containing stereoscopic depth selectively increase MEG activity in the parietal cortex while activity localised to the occipital areas is relatively constant for stimulus patterns containing fusion, rivalry and stereoscopic depth cues.

 
Mansfield, D. C., Shahani, U., McCulloch, D. L., Simpson, W. S.(2004). Dipole source modelling of the magnetoencephalogram to stereopsis, binocular fusion and rivalry[Abstract]. Journal of Vision, 4( 8): 601, 601a, http://journalofvision.org/4/8/601/, doi:10.1167/4.8.601. [CrossRef]
Footnotes
 Support: European Union under the NeuroBirch III Initiative, Helsinki, Finland
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×