2. J. Gandour, PhD, Linguistics B. Chandrasekaran, MS, Speech & Hearing J. Swaminathan, MS, Electrical Engineering Long term goal is to understand the nature of experience- dependent pitch representation at the brainstem level How pitch processing emerges from differential demands on auditory and linguistic processes Vary listeners: Mandarin Chinese, Thai, English Vary stimuli: speech/nonspeech (IRN); pitch contours R. KRISHNAN, PhD, Audiology

3. Previous Work (PET, fMRI, FFR) Cerebral CortexAuditory Brainstem

4. Current Work IRN (nonspeech stimuli; static vs. dynamic) Stimulus Response IRN block diagram IRN continuum Speech/Nonspeech Delay d Gain g + Delay d Gain g + Output, y(t)

5. Does language experience modulate the preattentive processing of linguistically- relevant pitch contours? Mismatch negativity mean amplitude reflects earliest levels of change detection in the cortex  MMN mean amplitude C>E: Early cortical processing of linguistic tones is facilitated by language experience  T2-T3 < T1-T2, T1-T3 in Chinese: Tonal space is shaped by language- specific phonological rules Chinese tone contrasts 050100150200250 70 80 90 100 110 120 130 140 050100150200250 70 80 90 100 110 120 130 140 050100150200250 70 80 90 100 110 120 130 140 Time (ms) T1-T3 T1-T2 T2-T3 Amplitude (microvolts) -4 -3 -2 0 1 2 -4 -3 -2 0 1 2 -1000100200300400500 -4 -3 -2 0 1 2 Time (ms) MMN Response T1-T3 T1-T2 T2-T3 F0 (Hz) CECE CECE Current Work MMN (Speech stimuli; Chinese vs. English) CECE

6. Future Directions develop non-invasive measures for multilingual population in USA and changes in pitch representation after retraining of hearing-impaired listeners develop optimal, language-sensitive signal processing strategies for conventional hearing aids and/or cochlear implants used by hearing- impaired listeners (i) linguistic sensitivity of this pitch representation by using stimuli changing in lexical status, direction of pitch change, and degree of similarity in the pitch contours (ii) tonal specificity … by using stimuli that either deviates in pitch contour from the lexical prototype of a given language or moves from one native phonetic prototype to another (iii) domain specificity … by using novel iterated ripple noise stimuli whose temporal regularity is systematically controlled (iv) laterality … by comparing pitch representation for right and left ear stimulation SPECIFIC AIMS PUBLIC HEALTH