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Attention and probability effects in the human occipital cortex: an optical imaging study
1Department of Psychology, University of Missouri, Columbia 85211, USA.
Neuroreport
|May 6, 1997
Summary
New imaging reveals neural activity, showing attention impacts extrastriate cortex early. Primary visual cortex responses are influenced by stimulus probability, suggesting pre-attentive memory.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Visual Neuroscience
Background:
- Understanding the temporal dynamics of neural activity is crucial for cognitive neuroscience.
- Previous research suggested attentional modulation in visual cortex, but precise timing remained unclear.
Purpose of the Study:
- To investigate the time course of neural activity in human visual cortex using a novel imaging technique.
- To examine the effects of spatial selective attention and stimulus probability on event-related activity in striate and extrastriate occipital areas.
Main Methods:
- Utilized the event-related optical signal (EROS) imaging technique to measure neural activity.
- Designed an experiment manipulating spatial selective attention and stimulus probability in normal human subjects.
- Analyzed event-related activity in striate (primary visual) and extrastriate occipital cortex.
Main Results:
- Attentional modulation was observed in extrastriate cortex with a latency under 100 ms.
- No significant attention effects were found in the initial response of the striate cortex.
- The initial response in the striate cortex was modulated by stimulus probability.
Conclusions:
- Attentional effects manifest early in extrastriate visual cortex, supporting prior models.
- The striate cortex's response to stimulus probability suggests pre-attentive memory mechanisms in primary visual processing.
- EROS imaging provides valuable temporal resolution for studying visual cortex function.