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A large-scale distributed network for covert spatial attention: further anatomical delineation based on stringent
D R Gitelman1, A C Nobre, T B Parrish
1Cognitive Neurology and Alzheimer's Disease Center, Department of Neurology, Northwestern University Medical School, Chicago, IL, USA. d-gitelman@nwu.edu
Brain : a Journal of Neurology
|June 4, 1999
Summary
This study used functional MRI to map brain activity during a spatial attention task. Findings reveal a network including frontal eye fields, parietal, and cingulate cortex, with right hemisphere dominance for spatial attention.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Neuroimaging
Background:
- Spatial attention is crucial for processing visual information.
- Previous functional MRI studies have identified brain networks involved in spatial attention.
- However, stringent controls for confounding factors like motor output and working memory are often lacking.
Purpose of the Study:
- To investigate cerebral activations during a spatial attention task using functional MRI.
- To apply rigorous behavioral and cognitive controls to isolate the neural correlates of spatial attention.
- To identify the specific cortical and subcortical brain regions involved in spatial attention networks.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed to measure brain activity in 12 healthy subjects.
- A spatial attention task was administered with strict controls to exclude motor output, visual fixation, eye movement inhibition, working memory, and no-go response components.
- Subjects were included only if they demonstrated attentional shifts during the task within the MRI scanner.
Main Results:
- Significant activations were observed in the hypothesized spatial attention network: lateral premotor cortex (frontal eye fields), posterior parietal cortex, and cingulate cortex.
- Subcortical activations were detected in the basal ganglia and thalamus.
- Eight out of ten subjects showed greater activation in the right parietal cortex, suggesting right hemisphere specialization for spatial attention. Posterior temporo-occipital cortex (MT+) and anterior insula also showed activation.
Conclusions:
- The study successfully identified a distributed network for spatial attention, including key cortical and subcortical areas.
- The findings support the specialization of the right hemisphere in processing spatial attention.
- The activation in the temporo-occipital area (MT+) suggests its role in the inferred shift of attentional focus across the visual scene.