title: Evidence of midline retinal nasotemporal overlap in healthy humans: a model for foveal sparing in hemianopia?
abstract: The existence of midline retinal nasotemporal overlap in humans is controversial. Here we used the Poffenberger paradigm and monocular vision to assess the existence of a midline retinal area projecting to both hemispheres and of a possible differential contribution of the two hemiretinae. When brief visual stimuli were presented at 1 degrees eccentricity they were responded to equally quickly with either hand while at 6 degrees the hand on the same side as the stimulated hemifield was consistently faster than the contralateral hand. This pattern of results is consistent with a nasotemporal overlap at 1 degrees and a complete lateralization at 6 degrees . Both hemiretinae contribute to the overlap area which can be considered as responsible for foveal sparing in hemianopic patients.
authors.affiliation: Department of Neurological & Visual Sciences, University of Verona and National Institute of Neuroscience, Verona, Italy. carloalberto.marzi@univr.it
authors.forename: C A
authors.initials: CA
authors.lastname: Marzi
authors.forename: F
authors.initials: F
authors.lastname: Mancini
authors.forename: I
authors.initials: I
authors.lastname: Sperandio
authors.forename: S
authors.initials: S
authors.lastname: Savazzi
mesh_terms: D000328:Adult; D005260:Female; D005584:Fovea Centralis; D006423:Hemianopsia; D006801:Humans; D008297:Male; D008959:Models, Neurological; D011930:Reaction Time; D012160:Retina / Q000502:physiology*; D015349:Vision, Monocular; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*