Involvement of striate and extrastriate visual cortical areas in spatial attention.
We investigated the cortical mechanisms of visual-spatial attention while subjects discriminated patterned targets within distractor arrays. Functional magnetic resonance imaging (fMRI) was used to map the boundaries of retinotopic visual areas and to localize attention-related changes in neural activity within several of those areas, including primary visual (striate) cortex. Event-related potentials (ERPs) and modeling of their neural sources, however, indicated that the initial sensory input to striate cortex at 50-55 milliseconds after the stimulus was not modulated by attention. The earliest facilitation of attended signals was observed in extrastriate visual areas, at 70-75 milliseconds. We hypothesize that the striate cortex modulation found with fMRI may represent a delayed, re-entrant feedback from higher visual areas or a sustained biasing of striate cortical neurons during attention. ERP recordings provide critical temporal information for analyzing the functional neuroanatomy of visual attention.
Martínez
A
A
Department of Psychology, University of California at San Diego, La Jolla 92093-0608, USA.
Anllo-Vento
L
L
Sereno
M I
MI
Frank
L R
LR
Buxton
R B
RB
Dubowitz
D J
DJ
Wong
E C
EC
Hinrichs
H
H
Heinze
H J
HJ
Hillyard
S A
SA
D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D004192:Discrimination, Psychological / Q000502:physiology; D005074:Evoked Potentials, Visual; D005246:Feedback; D005260:Female; D005829:Geniculate Bodies / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008959:Models, Neurological; D010296:Parietal Lobe / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology