The Auditory System: From Sound Waves to Brain Waves
Our human experience is enriched by our senses. The world would appear to be a dull place if the brain did not endow us with the ability to construct visual images, appreciate the complexity of a song, experience the touch of a loved one, and perceive the smells and tastes of our favorite foods. Each of these sensory modalities (vision, hearing, touch, smell, and taste) is incredibly complex, requiring specialized structures working in sync with interconnected network of neural circuits. Together, they allow for a rich experience of the world.
Last Monday, Kate introduced exciting research that showed how certain cells give rise to hair cells, the receptors of the inner ear that enable hearing. While 30,000 of these cells carry out auditory transduction into the human brain, the entire hearing process is much more complex. How we are able to distinguish and give meaning to a remarkable range of sounds? In the video below, let’s watch this process, which is nothing short of astonishing.
[youtube=http://www.youtube.com/watch?v=PeTriGTENoc]
The ear is special structure, performing the task of transducing the air vibrations caused by sound waves to nerve impulses that are perceived by the brain. Similar to touch, hearing requires high sensitivity to the movement of molecules in our surroundings. Check back on Friday to find out how we know exactly where sounds are coming from (sound localization)!
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References:
Kandel ER, Schwartz JH, Jessell TM 2000. Principles of Neural Science, 4th ed. McGraw-Hill, New York. ISBN 0-8385-7701-6.
Images adapted from WikiMedia and Corbis.
A fantastic tour of some of the mechanics of the ear. Thanks.