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Sensory-motor mechanisms in human parietal cortex underlie arbitrary visual decisions
Annalisa Tosoni1, Gaspare Galati, Gian Luca Romani
1Department of Clinical Sciences and Bioimaging, Institute for Advanced Biomedical Technologies, G. d'Annunzio Foundation, Via dei Vestini 31, Chieti 66013, Italy. tosonia@npg.wustl.edu
Nature Neuroscience
|November 11, 2008
Summary
Simple decisions involve accumulating sensory evidence. This study shows complex, arbitrary decisions also use sensory-motor mechanisms in the posterior parietal cortex for evidence integration.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Decision Neuroscience
Background:
- Perceptual decision-making is often viewed as gradual sensory evidence accumulation.
- This mechanism is well-studied in simple tasks, like motion discrimination in monkeys.
- Generalizability to complex, arbitrary decisions remains unclear.
Purpose of the Study:
- To investigate if sensory evidence accumulation mechanisms apply to complex decisions based on arbitrary associations.
- To explore the role of the posterior parietal cortex in arbitrary stimulus-response decisions.
Main Methods:
- Utilized a task involving arbitrary associations between visual stimuli (faces/places) and actions (eye/hand movements).
- Measured neural activity in human posterior parietal cortex using functional neuroimaging.
- Analyzed how neural activity reflected the strength of sensory evidence.
Main Results:
- Activity in effector-specific regions of the posterior parietal cortex correlated with the strength of sensory evidence for a given response.
- These neural regions integrated sensory evidence rather than just responding to the stimuli.
- Evidence accumulation was observed even for arbitrary stimulus-response mappings.
Conclusions:
- The findings suggest that sensory-motor mechanisms, involving evidence integration, underlie even arbitrary decision-making.
- Contextual stimulus-response associations can trigger these integrative neural processes.
- This extends the concept of evidence accumulation beyond simple perceptual tasks.
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