Built-in Amps: How Subtle Head Motions, Quiet Sounds Are Reported to the Brain

(Original Link - http://www.sciencedaily.com/releases/2010/02/100209091842.htm)

The phrase "perk up your ears" made more sense last year after scientists discovered how the quietest sounds are amplified in the cochlea before being transmitted to the brain.

When a sound is barely audible, extremely sensitive inner-ear "hair cells" -- which are neurons equipped with tiny, sensory hairs on their surface -- pump up the sound by their very motion and mechanically amplify it. Richard Rabbitt of the University of Utah, a faculty member in the MBL's Biology of the Inner Ear course, reported last spring on the magnification powers of the hair cell's hairs.

Now, Rabbitt and MBL senior scientist Stephen Highstein have evidence that hair cells perform similarly in another context -- in the vestibular system, which sends information about balance and spatial orientation to the brain.

"The bottom line is we have 'accelerometers' in the head that report on the direction of gravity and the motion of the head to the brain," says Highstein. "What we found is they respond with a greater magnitude than expected for very small motions of the head. This brought to mind a similar amplification of very small signals by the human inner-ear cochlea. And, in fact, the vestibular system and the cochlea have a sensory element in common: the hair cells." Rabbitt and Highstein found that, in both the auditory and the vestibular systems, the hair cell response exhibits "compressional nonlinearity": The lower the strength of the stimulus, the more the hair cells "tune themselves up to amplify the stimulus," Highstein says.

The toadfish was used for this study. "What's interesting is the boney fishes evolved some 3 to 4 million years ago; subsequently this feature of its hair cells was apparently co-opted by the mammalian cochlea. Evolution conserved this feature, and the mammal later used it to improve hearing sensitivity," Highstein says.

Hearing the Music, Honing the Mind

(Original Link - http://www.scientificamerican.com/article.cfm?id=hearing-the-music-honing)

Music produces profound and lasting changes in the brain. Schools should add classes, not cut them.

 

Nearly 20 years ago a small study advanced the notion that listening to Mozart’s Sonata for Two Pianos in D Major could boost mental functioning. It was not long before trademarked “Mozart effect” products appealed to neurotic parents aiming to put toddlers on the fast track to the Ivy League. Georgia’s governor even proposed giving every newborn there a classical CD or cassette.

The evidence for Mozart therapy turned out to be flimsy, perhaps nonexistent, although the original study never claimed anything more than a temporary and limited effect. In recent years, however, neuroscientists have examined the benefits of a concerted effort to study and practice music, as opposed to playing a Mozart CD or a computer-based “brain fitness” game once in a while. Advanced monitoring techniques have enabled scientists to see what happens inside your head when you listen to your mother and actually practice the violin for an hour every afternoon. And they have found that music lessons can produce profound and lasting changes that enhance the general ability to learn. These results should disabuse public officials of the idea that music classes are a mere frill, ripe for discarding in the budget crises that constantly beset public schools.

Studies have shown that assiduous instrument training from an early age can help the brain to process sounds better, making it easier to stay focused when absorbing other subjects, from literature to tensor calculus. The musically adept are better able to concentrate on a biology lesson despite the racket in the classroom or, a few years later, to finish a call with a client when a colleague in the next cubicle starts screaming at an underling. They can attend to several things at once in the mental scratch pad called working memory, an essential skill in this  era of multitasking.

Discerning subtleties in pitch and timing can also help children or adults in learning a new language. The current craze for high school Mandarin classes furnishes an ideal example. The difference between m¯a (a high, level tone) and mà (falling tone) represents the difference between “mother” and “scold.” Musicians, studies show, are better than nonmusicians at picking out easily when your m¯a is màing you to practice. These skills may also help the learning disabled improve speech comprehension.
Sadly, fewer schools are giving students an opportunity to learn an instrument.

In Nature Reviews Neuroscience this summer, Nina Kraus of Northwestern University and Bha­rath Chandrasekaran of the University of Texas at Austin, who research how music affects the brain, point to a disturbing trend of a decline of music education as part of the standard curriculum. A report by the advocacy organization Music for All Foundation found that from 1999 to 2004 the number of students taking music programs in California public schools dropped by 50 percent.

Research of our brains on music leads to the conclusion that music education needs to be preserved—and revamped, as needed, when further insights demonstrate, say, how the concentration mustered to play the clarinet or the oboe can help a problem student focus better in math class. The main reason for playing an instrument, of course, will always be the sheer joy of blowing a horn or banging out chords. But we should also be working to incorporate into the curriculum our new knowledge of music’s beneficial effect on the developing brain. Sustained involvement with an instrument from an early age is an achievable goal even with tight budgets. Music is not just an “extra.”
 

Music and the Mind - Aniruddh Patel Ph.D. - VIDEO