Modulation of visual perception by eye gaze direction in patients with spatial neglect and extinction.
Parietal neurons have retinotopic receptive fields whose response is modulated by eye gaze signals. We examined the role of eye position and eye movement direction on visual extinction in three patients with parietal damage and left neglect, characterized by impaired perception of contralesional field stimuli despite intact visual cortex. Patients tracked a horizontally moving fixation point, while discriminating fine changes at the fixated point and detecting more salient targets flashed on either side of fixation. Eye position modulated extinction, with worse detection of left field targets during eccentric fixation towards the left. Direction of eye movement also modulated extinction, with worse detection of left targets during rightward scanning. These results demonstrate that extinction in contralesional field is influenced by extra-retinal factors related to eye position and eye movements, consistent with a convergence of these signals in parietal cortex.
Vuilleumier
P
P
Institute of Cognitive Neuroscience, University College, Alexandra House, 17 Queen Square, London WC1N 3AR, UK.
Schwartz
S
S
D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D005108:Extinction, Psychological / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000503:physiopathology*; D010775:Photic Stimulation; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*