May 2005
Volume 46, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2005
Retinotopic Mapping in Patients With Scotomas From Retinal Disease
Author Affiliations & Notes
  • J.S. Sunness
    Ophthalmology, Johns Hopkins Wilmer Eye Inst, Baltimore, MD
  • B.J. Rosenau
    Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD
  • A.S. Greenberg
    Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD
  • C.A. Applegate
    Ophthalmology, Johns Hopkins Wilmer Eye Inst, Baltimore, MD
  • S. Yantis
    Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD
  • Footnotes
    Commercial Relationships  J.S. Sunness, None; B.J. Rosenau, None; A.S. Greenberg, None; C.A. Applegate, None; S. Yantis, None.
  • Footnotes
    Support  NIH Grant EY14148
Investigative Ophthalmology & Visual Science May 2005, Vol.46, 4786. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      J.S. Sunness, B.J. Rosenau, A.S. Greenberg, C.A. Applegate, S. Yantis; Retinotopic Mapping in Patients With Scotomas From Retinal Disease . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4786.

      Download citation file:


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

      ×
  • Supplements
Abstract

Abstract: : Purpose: To determine whether there is cortical remapping in the lesion projection zone (LPZ), the region of visual cortex corresponding to the position of the retinal lesion. Methods: We tested five patients with scotomas caused by retinitis pigmentosa (peripheral lesion, spared fovea), chorioretinal atrophy (nasal to the fovea and extending superior and inferior to the fovea in each eye), or age–related macular degeneration (one with eccentric fixation and no sparing of the fovea, one with a central scotoma with a tiny spared foveal area, and one with a thin annular scotoma). Scanning laser ophthalmoscope (SLO) perimetry was used to define the area of dense scotoma and the site and stability of fixation. Subjects met criteria for participation if their scotomas included retina within the central 25.6 degrees of vision and if they could maintain stable fixation. Functional magnetic resonance imaging (fMRI) of visual cortex was performed while patients viewed sequences of five logarithmically scaled annular rings consisting of contrast reversing radial checks that tiled the visual field from 1.5 to 12.8 degrees eccentricity. During scanning, one ring at a time was displayed in 16 second epochs, interspersed with fixation–only epochs. FMRI data from all epochs of each ring were contrasted with data from fixation epochs, separately for each patient. Functional maps from each contrast were projected onto a cortical surface representation. Results: In regions of cortex outside each subject’s LPZ, retinotopic mapping yielded patterns of activation similar to those found in normal subjects: a progressive change of the location of cortical activation evoked by the rings as they stimulated adjacent areas of retina. In the LPZ, four patients failed to exhibit retinotopic activation. In one patient, whose scotoma was in the shape of a thin ring, all stimulus rings that overlaid the scotoma also overlaid areas of intact retina. This prevented a clear demarcation of the LPZ for this thin scotoma. Conclusions: In areas of cortex innervated by intact retina, we observed retinotopically organized cortical activation. Retinotopic activation was absent in the LPZ in four of five patients. If remapping had occurred, activity should have been observed in the LPZ during stimulation of good retina outside the lesion. These results suggest that little significant cortical remapping has occurred in these patients, whose lesions have been present for several years in each case.

Keywords: low vision • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual cortex 
×
×

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.

×