Magnocellular and parvocellular visual pathway contributions to visual field anisotropies.
It is well established that sensitivity is not necessarily equivalent at isoeccentric locations across the visual field. The focus of this study was a psychophysical examination of the spatial sensitivity differences between the upper and lower visual hemifields under conditions biased toward the presumed magnocellular or parvocellular visual pathway. Experiment 1 showed higher contrast sensitivity in the lower visual field when visual sensitivity was biased toward the parvocellular pathway; no visual field anisotropy was found when sensitivity was biased toward the magnocellular pathway. Experiment 2 showed that the magnitude of the contrast sensitivity anisotropy within the presumed parvocellular pathway increased when test targets of higher spatial frequency were used. The results of this study have relevance for the design both of psychophysical paradigms and clinical training programs for patients with heterogeneous visual field loss.
McAnany
J Jason
JJ
Department of Psychology and Laboratory of Integrative Neuroscience, The University of Illinois at Chicago, M/C 285, 1007 West Harrison Street, Chicago, IL 60607-7137, USA. jmcana1@uic.edu
Levine
Michael W
MW
D000328:Adult; D016880:Anisotropy; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012684:Sensory Thresholds / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*