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Signed and spoken language perception studied by positron emission tomography
B Söderfeldt1, M Ingvar, J Rönnberg
1Department of Clinical Neuroscience, University Hospital, Linköping, Sweden.
Neurology
|July 1, 1997
Summary
Sign and spoken language perception activate overlapping brain regions in bilingual individuals. This suggests a shared neural basis for visual and auditory language processing, impacting brain activity patterns.
Area of Science:
- Neuroscience
- Cognitive Science
- Linguistics
Background:
- Sign and spoken languages appear to engage similar brain regions.
- Similar regional cerebral blood flow (rCBF) patterns are observed, despite sign language's spatial nature.
Purpose of the Study:
- Investigate sign and spoken language perception in healthy bilingual subjects.
- Examine the neural correlates of visual (sign) versus auditory (spoken) language processing.
Main Methods:
- Utilized Positron Emission Tomography (PET) imaging during four videotaped conditions.
- Conditions included sign language, spoken language, spoken language with mouth covered, and spoken language with a motionless face.
Main Results:
- Spoken language (condition 4) activated the bilateral perisylvian cortex (Brodmann areas 22 and 43).
- Sign language activated visual association areas (Brodmann areas 37 and 19) but not selectively parietal regions.
- A reciprocal relationship was found between visual and auditory perception area activation levels.
Conclusions:
- Sign language perception, via the visual route in bilinguals, shows functional anatomy overlap with language processing.
- This overlap encompasses both auditory and visual components of language.
- Findings suggest a unified neural framework for processing different language modalities.