Neural processing of language in the absence of auditory input

Naja Ferjan RamirezIn collaboration with Matt Leonard, Christina Torres, Marla

Hatrak, Eric Halgren, & Rachel Maybery

Mayberry LabMultimodal Imaging Lab

Cognitive Neuroscience 2013 Spring Retreat & Kavli Institute for Brain and Mind Symposium

AUDITORY WORDS WRITTEN WORDS

• Are the neural underpinnings of word meaning dependent on auditory language experience?– Congenitally deaf individuals receive no auditory input– Some acquire sign language as their native language from birth

Is the meaning of ASL signs in deaf native signers processed like the meaning of auditory & written words in hearing people (i.e. left dominant, fronto-temporal areas)?

Early stages = modality specific

Later stages = modality independent?Left dominant lexico-semantic network

Marinkovic et al. 2003

100 200 300 400 500 600

ms

ampl

itude

700

Word Onset

Average waveform from single MEG sensor

- Deaf native signers (n=11) watch ASL signs

- Hearing English speakers (n=8) listen to English words

Anatomically constrained Magnetoencephalography

Integrating MEG (temporal resolution)…

100 200 300 400 500 600

ms700

… with MRI (spatial resolution)

Method: Dale et al, 2000

Sensory processing: Modality specific

Lexico-semantic processing:Independent of modality through which early language is received

Neural systems for high-level language processing are supramodal!

Sign in native deaf 300-350 ms

Speech in hearing 300-350 ms

Thank you!

NSF BCS-0924539NIH RO1DC012797