Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations
BMC Neurosci. 2004-01-01; 5(1): 35
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1. BMC Neurosci. 2004 Sep 19;5:35.
Early visual evoked potentials are modulated by eye position in humans induced by
whole body rotations.
Andersson F(1), Etard O, Denise P, Petit L.
(1)Groupe d’Imagerie Neurofonctionnelle (GIN) UMR6194, CNRS-CEA-University of
Caen and Paris 5, GIP CYCERON, BP5229, Bd. Becquerel, 14074 Caen, France.
BACKGROUND: To reach and grasp an object in space on the basis of its image cast
on the retina requires different coordinate transformations that take into
account gaze and limb positioning. Eye position in the orbit influences the
image’s conversion from retinotopic (eye-centered) coordinates to an egocentric
frame necessary for guiding action. Neuroimaging studies have revealed eye
position-dependent activity in extrastriate visual, parietal and frontal areas
that is along the visuo-motor pathway. At the earliest vision stage, the role of
the primary visual area (V1) in this process remains unclear. We used an
experimental design based on pattern-onset visual evoked potentials (VEP)
recordings to study the effect of eye position on V1 activity in humans.
RESULTS: We showed that the amplitude of the initial C1 component of VEP,
acknowledged to originate in V1, was modulated by the eye position. We also
established that putative spontaneous small saccades related to eccentric
fixation, as well as retinal disparity cannot explain the effects of changing C1
amplitude of VEP in the present study.
CONCLUSIONS: The present modulation of the early component of VEP suggests an eye
position-dependent activity of the human primary visual area. Our findings also
evidence that cortical processes combine information about the position of the
stimulus on the retinae with information about the location of the eyes in their
orbit as early as the stage of primary visual area.
PMID: 15377390 [Indexed for MEDLINE]