1 / 33

SPHSC 462 HEARING DEVELOPMENT

This course provides a comprehensive review of hearing science, focusing on sound characteristics, auditory nerve responses, and coding mechanisms. Explore how intensity, frequency, and temporal aspects of sound are represented in the auditory system, from conduction to transduction. Discover the active mechanism involved in representing sound and decoding auditory information. Gain insights into psychophysics and the fascinating world of sound perception. Enhance your understanding of auditory development and frequency representation through engaging discussions and take-home exams. For detailed lecture notes and resources, visit the course website. 8

jeanniee
Download Presentation

SPHSC 462 HEARING DEVELOPMENT

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SPHSC 462HEARING DEVELOPMENT Overview Review of Hearing Science Introduction

  2. Overview of course and requirements • Lecture/discussion; lecture notes on website http://faculty.washington.edu/lawerner/sphsc462/ • No text; chapter and other readings on website • Requirements: two take-home exams (40% grade each) and discussion questions/in-class discussion of articles (20% grade).

  3. Exams • Take-home • Essay • Open book • Must work alone; penalty for breaking this rule is failing grade

  4. Article discussion • Articles every week starting Oct 15. • I will provide some questions to guide you through the articles. • You will submit one question about things you didn’t understand, one question that you think it would be interesting to discuss and answer the question, “How is this article relevant to me? by 5:30 am on discussion day.

  5. Drop boxes • Your discussion questions: • https://catalysttools.washington.edu/collectit/dropbox/lawerner/7177 • Take-home exams • https://catalysttools.washington.edu/collectit/dropbox/lawerner/7143

  6. Review of Hearing Science

  7. Hearing in a nutshell Wow! Psychophysics is interesting! TIME FREQUENCY

  8. What are the characteristics of sound represented in the auditory nerve response? • Intensity • Frequency • Temporal characteristics (changes in intensity or frequency over time)

  9. How does the ear come to represent these characteristics of sound? • Conduction • Transduction • Traveling wave and Active Mechanism

  10. Level (dB) Frequency (Hz) Level (dB) Frequency (Hz) Level (dB) Level (dB) Frequency (Hz) Frequency (Hz) Conduction

  11. Transduction: changing acoustic energy to electrochemical energy A C D B E F

  12. Where does the code for intensity come from? High level Low level Combined firing rate of auditory nerve fibers with the same best frequency

  13. Where does the code for frequency come from?

  14. Coding of the time waveform of sound: Tone Hair cell potential 0 Pressure Time Spikes Time Time

  15. Coding of the time waveform of sound: Complex waveform Hair cell potential 0 Time Pressure Time Spikes Time

  16. Coding of the time waveform of sound: High frequency tone Hair cell potential 0 Pressure Time Spikes Time Time

  17. Coding of the time waveform of sound: High frequency complex Hair cell potential 0 Pressure Time Spikes Time Time

  18. Where does the code for frequency come from? For low frequencies, a code for frequency is carried in the timing of auditory nerve action.

  19. Where does the code for temporal characteristics come from?

  20. Coding of the time waveform of sound: Temporal characteristics 0 0 Pressure Pressure Time Time Spikes Spikes Time Time

  21. Traveling wave and active mechanism The other code for frequency

  22. Basilar membrane motion Apex Base

  23. Traveling wave

  24. Traveling wave

  25. The active mechanism

  26. Intensity Frequency Temporal characteristics Combined firing rate of auditory nerve fibers with the same CF Place code and temporal code Phase-locking, but with limitations How are these three characteristics of sound represented in the auditory nerve response?

  27. So the message in the auditory nerve is sort of like a spectrogram TIME FREQUENCY = POSITION OF AN FIBER ALONG BASILAR MEMBRANE

  28. Hearing in a nutshell Wow! Psychophysics is interesting! TIME FREQUENCY

  29. Sound source segregation TIME FREQUENCY

  30. Cues that could be used to segregate components into sources • Spectral separation • Spectral profile • Harmonicity • Spatial separation • Temporal separation • Temporal onsets and offsets • Temporal modulations

  31. Hearing in a nutshell and sound source segregation Wow! Psychophysics is interesting! TIME FREQUENCY

  32. Acoustic cues used in localization Interaural intensity differences Interaural time differences Spectral shape cues

  33. For next time • Read p. 1-14 of “Human auditory development” chapter, Intro and Frequency representation

More Related