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Superior parietal cortex activation during spatial attention shifts and visual feature conjunction
M Corbetta1, G L Shulman, F M Miezin
1Department of Neurology and Neurological Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA.
Science (New York, N.Y.)
|November 3, 1995
Summary
Researchers used positron emission tomography to study brain activity during visual search tasks. A specific brain region in the superior parietal cortex was activated when searching for combined color and motion targets.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Visual Perception
Background:
- Understanding the neural mechanisms of visual attention is crucial for cognitive neuroscience.
- Previous research suggests spatial attention involves shifts within the visual field.
Purpose of the Study:
- To investigate regional cerebral blood flow changes during visual search for targets defined by color, motion, or conjunctions thereof.
- To identify brain regions involved in processing conjunction targets and their relation to spatial attention.
Main Methods:
- Positron emission tomography (PET) was employed to measure regional cerebral blood flow (rCBF).
- Participants performed visual search tasks with targets defined by single features (color or motion) or combined features (color and motion).
Main Results:
- A region in the superior parietal cortex showed activation exclusively during the conjunction search task.
- This activated region corresponds to a previously identified area involved in successive shifts of spatial attention.
- Detection time for conjunction targets increased with the number of display items, suggesting serial processing.
Conclusions:
- The superior parietal cortex plays a specific role in processing conjunction targets during visual search.
- The findings support a model where conjunction search relies on a mechanism that serially analyzes items, engaging spatial attention shifts.