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Neural consequences of competing stimuli in both visual hemifields: A physiological basis for visual extinction
Author(s) -
Fink Gereon R.,
Driver Jon,
Rorden Chris,
Baldeweg Torsten,
Dolan Raymond J.
Publication year - 2000
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/1531-8249(200004)47:4<440::aid-ana6>3.0.co;2-e
Subject(s) - psychology , neuroscience , stimulus (psychology) , binocular rivalry , extrastriate cortex , stimulation , visual cortex , extinction (optical mineralogy) , visual perception , perception , visual system , audiology , cognitive psychology , medicine , biology , paleontology
We used positron emission tomography in healthy volunteers to test hemispheric rivalry theories for normal and pathological spatial attention, which provide an influential account of contralesional extinction on bilateral stimulation after unilateral brain injury. Subjects reported visual characters presented either unilaterally or bilaterally. An extinction‐like pattern was found behaviorally, with characters in one hemifield reported less accurately when competing characters appeared in the other hemifield. Differences in neural activity for unilateral minus bilateral conditions revealed greater activation of striate and extrastriate areas for stimuli presented without competing stimuli in the other hemifield. Thus, simultaneous bilateral stimulation led to a significant reduction in response by spatiotopic visual cortex contralateral to a particular stimulus. These data provide physiological support for interhemispheric rivalry in the intact human brain, and demonstrate that such competition impacts at early levels of perceptual processing. Ann Neurol 2000;47:440–446.