“How Our Brain Constructs a Meaningful Sonic World”
Nina Kraus is director of the Brainvolts lab at Northwestern University. They have developed a technique called FFR (Frequency Following Response) that can measure the brain’s sound processing. Using FFR, over the past 30 years or so, they’ve done a lot of investigations into how the brain’s sound processing works.
Interesting items:
Sound is processed in many “old” areas of the brain — I interpret these areas as the “lizard brain” — more areas than other sensory channels. There are tie-ins to the emotions and movement areas (fight-or-flight mechanisms?).
The book uses the analogy of a sound mixing board to summarize the different aspects of sound that the brain focuses on:
- Fundamental frequency
- Harmonics
- FM sweeps
- Timing
- Stability
- Phase
- Noise
Discussion of the afferent/efferent nerve path is fascinating. The afferent path is outside-to-inside. I.e., how sounds from the world are detected and processed internally. The efferent path is inside-to-outside. This path tunes (programs) the afferent signal processing to optimize it for the tasks that are most important to the person.
The book has chapters that summarize how this optimization impacts: music and dance, rhythm, language, bilingual language, noise rejection, athletics, and the aging brain. There are fascinating implications of the overlaps between these optimizations. E.g., learning to play a music instrument improves the ability to process speech; playing a sport also improves speech processing; speaking multiple languages improves musical activity; etc.
A very enjoyable and informative read. Highly recommended.