Neural Activity During Mental Rotation in Deaf Signers: The Influence of Long-Term Sign Language Experience

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Mental rotation is a key visuospatial ability.
• Deaf signers have previously shown enhanced nonlinguistic visual task performance.
• Neural underpinnings of these enhancements are not fully understood.

Purpose of the Study:

• To investigate neural differences in mental rotation processing between deaf signers and hearing nonsigners.
• To utilize functional magnetic resonance imaging (fMRI) to compare brain activation patterns.
• To explore how long-term sign language use impacts visuospatial cognition.

Main Methods:

• Participants included deaf signers and hearing nonsigners.
• A block-designed fMRI experiment was employed.
• Participants performed 3D mental rotation and comparison tasks.
• Data analyzed using factorial ANOVA for group and task effects.

Main Results:

• Both groups activated bilateral occipital, parietal, and posterior temporal lobes during rotation.
• Significant group-by-task interactions were observed in areas including the anterior cingulate and inferior frontal gyrus.
• Deaf signers showed right-hemisphere dominant activation, while hearing nonsigners showed bilateral activation during rotation.
• Deaf signers exhibited decreased activation in regions like the parahippocampal gyrus and posterior cingulate cortex compared to hearing nonsigners.

Conclusions:

• Decreased activation in deaf signers suggests enhanced neural efficiency and refined circuitry from sign language experience.
• Findings tentatively suggest a right-hemisphere lateralization pattern for mental rotation in deaf signers.
• Sign language processing may positively influence nonlinguistic visuospatial abilities.