Prosodic and narrative processing in American Sign Language: an fMRI study.

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Signed languages like American Sign Language (ASL) share core linguistic properties with spoken languages.
• Previous research suggests left hemisphere dominance for both signed and spoken languages.
• The role of the right hemisphere (RH) in sign language processing remains less understood.

Purpose of the Study:

• To investigate the role of the right hemisphere in processing narrative information in American Sign Language (ASL).
• To compare brain activation patterns for ASL narrative cues with those in spoken languages.
• To determine if modality or linguistic content drives brain organization for language.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to study Deaf native signers.
• Participants processed ASL sentences with and without narrative devices.
• Brain activation was analyzed for differences related to narrative content.

Main Results:

• Robust bilateral activation of language cortices, basal ganglia, and medial regions was observed for all ASL sentences.
• Greater right hemisphere activation in the inferior frontal gyrus and superior temporal sulcus was found for ASL sentences with narrative devices.
• These RH areas are known to process narrative content in spoken languages.

Conclusions:

• Natural human languages, regardless of modality, utilize a core set of left hemisphere brain regions.
• Right hemisphere involvement in processing narrative linguistic functions is conserved across signed and spoken languages.
• This study extends understanding of RH contributions to language processing in signed languages.