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The brain network underlying serial visual search: comparing overt and covert spatial orienting, for activations and
S L Fairhall1, I Indovina, J Driver
1Neuroimaging Laboratory, Santa Lucia Foundation, 00179 Rome, Italy. s.fairhall@hsantalucia.it
Cerebral Cortex (New York, N.Y. : 1991)
|April 28, 2009
Summary
Goal-directed attention engages the dorsal fronto-parietal network regardless of eye movements. However, information flow within this network and subcortical engagement differ between overt and covert attention during visual search.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Visual Attention Research
Background:
- Understanding the neural mechanisms of attention is crucial for cognitive neuroscience.
- Distinguishing between overt (eye-movement-accompanied) and covert (eye-movement-independent) attention is key to mapping attentional processes.
- Previous research suggests the dorsal fronto-parietal network is involved in goal-directed attention.
Purpose of the Study:
- To investigate the brain basis of overt and covert attention during visual search using functional magnetic resonance imaging (fMRI).
- To examine how eye movements and attentional shifts influence brain activity and connectivity.
- To compare goal-directed search with stimulus-driven tracking.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
- A factorial design compared overt and covert attention in goal-directed serial search versus stimulus-driven tracking.
- Effective connectivity analyses were performed to assess information flow within attention networks.
Main Results:
- Cortical activation in the dorsal fronto-parietal network was similar for overt and covert goal-directed attention, independent of oculomotor control.
- Effective connectivity within the dorsal fronto-parietal network significantly varied with task type (goal-directed vs. stimulus-driven) and attention form (overt vs. covert).
- Subcortical regions, including the pulvinar and caudate nucleus, were preferentially engaged during covert goal-directed search.
Conclusions:
- The dorsal fronto-parietal attentional system dynamically reorganizes based on task demands and oculomotor requirements.
- Information flow within attention networks is modulated by the interplay between task goals and the modality of attention.
- Distinct subcortical involvement highlights specialized neural substrates for different attentional control mechanisms.
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