Presentation is loading. Please wait.

Presentation is loading. Please wait.

Sound is a pressure wave Figure by MIT OCW. After figure 11.1 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the.

Similar presentations


Presentation on theme: "Sound is a pressure wave Figure by MIT OCW. After figure 11.1 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the."— Presentation transcript:

1 Sound is a pressure wave Figure by MIT OCW. After figure 11.1 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964. Speed of sound -1000 ft/sec - 770 mi/hr

2 Figure by MIT OCW. After figure 11.3 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

3 The middle ear Figure by MIT OCW. After figure 11.5 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

4 Impedance matching Fluid in cochlea has higher impedance than air : reflection could be a problem. Pressure at the cochlea is amplified relative to pressure at the eardrum Force = pressure x area Work = force x distance

5 The cochlea is a Fourier analyzer Input –Pressure Output –Auditory nerve fibers –Each fibers is selective for sounds of a characteristic frequency

6 Pure tones Figure by MIT OCW. After figure 11.2 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

7 Frequency tuning analogous to visual receptive field,with frequency playing the role of space Figure by MIT OCW. After figure 11.19 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

8 Fourier analysis and synthesis Any signal can be written as a sum of sine waves. Any sound is a combination of pure tones.

9 Power spectrum Graph of power versus frequency.

10 Spectrogram Power spectrum as a function of time. Power versus frequency and time.

11 Critical bands through masking Detection of pure tone depends on bandwidth of masking noise only if it is narrower than a critical value The critical value corresonds roughly to the width of frequency tuning of auditory nerve fibers

12 Three scale of the cochlea Figure by MIT OCW. After figure 11.7 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

13 Basilar membrane Images removed due to copyright reasons. Please see figure 11.8 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

14 Structural gradient Base is 100 times stiffer than apex. Frequency and amplitude of a traveling wave vary along the basilar membrane. Figure by MIT OCW. After figure 11.9 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

15 Place code for frequency Figure by MIT OCW. After figure 11.10 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

16 Hair cells and stereocilia Images removed due to copyright reasons. Please see figures 11.11 a and b in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.

17 The organ of Corti Inner hair cells –Single row of 3500 –Tip end below tectorial membrance Outer hair cells –Three rows of 5000 –Tip attached to tectorial membrance Synapse onto spiral ganglion cells. Figure by MIT OCW. After figure 12.11in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the Brain. 2nd ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2001. ISBN: 0683305964.


Download ppt "Sound is a pressure wave Figure by MIT OCW. After figure 11.1 in: Bear, Mark F., Barry W. Connors, and Michael A. Paradiso. Neuroscience: Exploring the."

Similar presentations


Ads by Google