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Lookup NU author(s): Professor Alexander Thiele
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations "around the clock." Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations.
Author(s): Connolly JD, Vuong QC, Thiele A
Publication type: Article
Publication status: Published
Journal: Cerebral Cortex
Print publication date: 01/06/2015
Online publication date: 18/12/2013
Date deposited: 07/07/2015
ISSN (print): 1047-3211
ISSN (electronic): 1460-2199
Publisher: Oxford University Press
PubMed id: PMC4428299
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