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Speech Sound Processing in the Brain. Mike Kilgard University of Texas at Dallas. Hearing and Language. Hearing. is in the BRAIN. What was that sound?. ?. ?. ?. ?. OR. ?. ?. ?. ?. High. 20. 18. 14. 16. 12. 10. 8. 6. 4. Low. 2 kHz.
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Speech Sound Processing in the Brain Mike Kilgard University of Texas at Dallas
Hearing is in the BRAIN.
What was that sound? ? ? ? ?
OR ? ? ? ?
High 20 18 14 16 12 10 8 6 4 Low 2 kHz 0 0.1 0.2 0.3 0.4 0.5 Seconds 20 High 18 14 16 12 10 8 6 4 Low 2 kHz 0 0.1 0.2 0.3 0.4 0.5 Seconds
8000 Hz 7000 6000 5000 4000 3000 2000 Frequency 1000 0 0 .5 1.0 1.5 2.0 2.5 Seconds Spectrogram - Example Sounds
Example Speech Sound - “Bad” 8000 Hz 7000 6000 5000 4000 3000 2000 Frequency 1000 0 0 .1 .2 .3 .4 .5 Seconds
“Pad” vs. “Bad” 8000 Hz 7000 6000 5000 4000 3000 2000 Frequency 1000 Time 0 0 .1 .2 .3 .4 .5 Seconds
Brain Responses Da vs. Ga Normal Learning Impaired Kraus and colleagues, Science 1996
Molfese, Brain & Language, 2000 Infant brain responses may predict reading 8 years later.
Environmental Enrichment RedGroup Enriched Blue Enriched 20±10 vs. 75±20μV81±19 vs. 37±20 μV 22 rats total
Environment Physically Alters the Brain! Standard Enriched
Training Improves the Brain
Before Training After Training
“Pad” vs. “Bad” 8000 Hz 7000 6000 5000 4000 3000 2000 Frequency 1000 Time 0 0 .1 .2 .3 .4 .5 Seconds
Sad vs. Dad is Easy. High Medium Low Time (milliseconds)
Rad vs. Lad is Hard. High Medium Low Time (milliseconds)
But rats can’t hear speech. (or can they?) Dad? or Sad?
Although rats will never learn to talk or read, this new model is providing new insights into the early stages of speech processing and how they might be improved.
Conclusions: 1. Hearing happens in the brain. ? ? ? ? 2. Fractions of a second matter. 3. The brain doesn’t always do a good job. 4. The brain can change. 5. Our new understanding of neural speech processing may aid development of new therapies.
Acknowledgements: www.utd.edu/~kilgard Crystal Engineer Claudia Perez Helen Chen National Institute for Deafness and Other Communicative Disorders