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Feeling with the mind's eye: contribution of visual cortex to tactile perception
1Department of Neurology, Emory University School of Medicine, WMRB 6000, PO Drawer V, Atlanta, GA 30322, USA. ksathia@emory.edu
Behavioural Brain Research
|October 3, 2002
Summary
Visual cortex activation is necessary for tactile orientation sensing in sighted individuals. This research explores cross-modal interactions between vision and touch, highlighting the visual cortex's role in tactile perception.
Area of Science:
- Neuroscience
- Sensory Perception
- Cross-modal Interactions
Background:
- Normal perception involves cross-modal interactions, where senses influence each other.
- Visual imagery plays a role in tactile perception of object properties.
Purpose of the Study:
- To investigate cross-modal interactions between vision and touch in normally sighted humans.
- To determine the necessity of visual cortex involvement in tactile perception.
Main Methods:
- Utilized positron emission tomography (PET) to identify brain regions active during tactile tasks.
- Employed transcranial magnetic stimulation (TMS) to disrupt specific brain regions and assess functional necessity.
Main Results:
- PET scans showed activation in the extrastriate visual cortex (near the parieto-occipital fissure) during tactile orientation discrimination.
- TMS applied to this visual cortex region impaired performance on the tactile orientation task.
- Visual cortex involvement was specific to orientation discrimination, not spatial frequency discrimination.
Conclusions:
- The identified extrastriate visual cortex region is not only active but also necessary for optimal tactile sensing of orientation.
- These findings suggest a crucial role for visual processing areas in tactile perception of orientation.
- Re-evaluation of visual cortex involvement in Braille reading for the blind may be warranted from this perspective.
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