CH 5 Auditory Perception (TERMS)

Question 1

Sound (2)

Answer 1

• Mechanical energy
• Consists of waves of compression and rarefaction

Question 2

Compression

Answer 2

High pressure (crest)

Question 3

Rarefaction

Answer 3

Low pressure (trough)

Question 4

Transduction

Answer 4

The process of converting environmental energy (light wave, sound waves) into neural signals

Question 5

Place theory (4)

Answer 5

• Works best with higher frequencies

States that different frequencies stimulate specific locations on the basilar membrane, allowing the brain to perceive pitch based on where activation occurs.

• High frequencies stimulate the narrow, stiff base near the oval window.
• Low frequencies stimulate the wider, more flexible apex of the cochlea.

This spatial coding of sound helps explain how we perceive high-pitched sounds, as different pitches are mapped along the basilar membrane.

Question 6

Tonotopic mapping

Answer 6

Orderly layout of frequency coding along basilar membrane

• Resolution for high frequencies good but poor for low frequencies (less than 250 Hz)

Question 7

Frequency theory (5)

Answer 7

• Works best with lower frequencies
• The entire basilar membrane vibrates at the same frequency as the incoming sound wave
• The neural firing rate in the auditory nerve matches the frequency of the sound.
  
  • Example: A 200 Hz sound causes neurons to fire 200 times per second
• Limitation neurons have a maximum firing rate of about 1,000 times per second, which limits the ability to encode higher frequencies
  
  • Solved by Volley Principle

Question 8

Volley Principle (1,2)

Answer 8

• Solves the limitation of frequency theory

Networks of coordinated neurons fire sequentially to code for frequency above 1000/sec

• Neurons are firing at different times, creating a higher response rate than the refractory period (max neural firing rate)