Cognitive Neuroscience Lecture 12: Language Lecture 2

''L12: Language Lecture 2''

Innateness of language

-         Bavelier: innateness

Applications

-         Weiduschat: rTMS for aphasia

Genetic blueprint for language

-         H1: left hemi spoken

-         H2: Left hemi grammatical

Deafness—sign language fMRI

-         asl is visuospatial and fully grammatical

-         not translation

-         can help determine between h1 and h2

Bavelier

-         determine if neural substrates for ASL are same as English

o normal speakers no SL

o congenitally deaf native ASL

o normally hearing, bilingual ASL and English

-         Scanning conditions designed to ID language processing

o English material: sentences vs. consonant strings

o ASL: sentences vs non-sign that look like sign

-         Presentation

o Each run: 4 cycles

o 2 english runs, 2 ASL runs

-         Behavioral task: recognition of stim in run

-         Data analysis:

o Broca’s area

o Wernicke’s area

-         Average activation of all voxels in ROI compared for sentences vs. non sentences in each subject group

-         2 critical questions

o Sig LH for both groups in both areas?

o Do the 2 groups differ to degree which activation is left lateralized?

-         Conclusions of Bavelier:

o Left hemisphere: IFG and STG recruited when both deaf and hearing individuals engaged in processing

o Consistent with hypothesis 2: grammatical, not spoken

o Right Hemi: ASL ALSO recruits right hemi in signers (deaf or hearing)àless LH lateralization

o What is happening in RH? à linguistic use of space in sign language

-         Paradoxical functionalr facilitation (Sprague)

o 1st lesion causes defecit

o 2nd lesion causes improvement

§ Overinhibition

o Sprague in language: balance between RH and LH may allow

o What happens when LH damaged?

§ Right hemi overinhibits

§ Additional damage/disruptionàless inhibitàimprove LH

o Aphasiaàbetter recovery after increase in LH recruitment not RH recruitment

-         Prediction: decrease right hemi decreases RH inhibition

-         Better LH recovery

-         rTMS à slow = permanent

-         PET scans measures language activation

-         Rehab: 2 weeks including rTMS

-         Stim group tMS over IFG

-         Sham group: vertex

-         Ifg localization from mr scans

-         rTMS and 45 mins of therapy

Data analysis

LI: laterality index (LH/total)

LI for IFG, upper temporal, sup. Motor

LI shift to left hemi from pre to post treatment in IFG/Broca’s

Greater lang improvement for TMS

Activation during verb generation pre and post

-         tms subject: reactivation of LH structures

-         sham subject: increasing RH activity

conclusions: inhibitory magnetic stim of right hemi broca and therapy prevents right hemi lateralization

RH negative? what if rTMS applied to LH