Neural systems underlying lexical retrieval for sign language

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Spoken language research indicates specific neural areas for lexical retrieval.
• The neural organization of signed languages, like American Sign Language (ASL), remains less understood.

Purpose of the Study:

• To investigate if signed languages activate similar neural regions as spoken languages during lexical retrieval.
• To compare brain activation patterns for different types of ASL signs (fingerspelled vs. native).

Main Methods:

• Positron emission tomography (PET) was employed to scan the brains of ten deaf native ASL signers.
• Participants were presented with images of famous persons and animals to elicit signed responses (fingerspelled or native signs).

Main Results:

• Retrieving ASL signs activated neural sites comparable to those for spoken English words.
• Naming famous persons activated the left temporal pole; naming animals activated the left inferotemporal cortex.
• Fingerspelled signs engaged additional premotor areas compared to native signs, likely due to increased motor planning.

Conclusions:

• Similar neuroanatomical areas are involved in lexical retrieval for both signed and spoken languages.
• The study supports the universality of brain organization for language, regardless of modality.