by John Wong
The science of the transmission of information in the auditory system is a subject of research of Malvin Teich, a professor of Columbia's electrical engineering department who recently was elected to the Acoustical Society of America for his research in helping people understand how sound is converted to electrical impulses in the human nervous system.
In the human ear, the snail shaped cochlea transforms incoming sound waves into a sequence of electrical impulses. The intermediate processes take many forms. The incoming sounds take the form of mechanical vibrations that hits the inner ear. Then, the vibrations comes into contact with fluids inside the ear, causing a hydrodynamic force. This force hits the hairs inside the ear, which in turn triggers a chemical change, as the hairs causes the flow of ions to run through an ion channel. These ions are then amplified, causing the transfer of neurotransmitters through synapses. These neurotransmitters attach themselves to certain nerve fibers, causing a series of electrical impulses, which take the form of digital signals. The action potential from this process causes nerve spikes, transferred by clusters of as many as 50,000 nerve fibers to the higher auditory centers in the brain.
The transmission of information from the inner ear to the auditory center occurs through the VIIth cranial nerve. The electrical signals are transferred through the individual fibersof this nerve, called auditory neurons. This topic of research is important because the results tell us about the nature of information encoding. This electric signal is made up of short electrical action potentials called nerve spikes. Professor Teich found that these electric signals manifest themselves as fractals, which are series of clusters, with each cluster itself made of clusters. He believes that the research is important for helping people understand aspects of sound such as loudness and pitch.
An interesting part of Teich's research is that it is interdisciplinary. Teich initially became interested in hearing research from listening to a lecture by William J. McGill, a mathematical psychologist in 1974. The lecture was based on a mathematical explanation of how auditory information was detected and stored in the higher centers of the brain. Teich, then a researcher in the field of electrical engineering, along with McGill, eventually found that Teich's own field of research, the detection of laser light, and McGill's research interest, the transmission of neural information in the auditory system, had identical explanations.
Teich, who joined Columbia's faculty in 1967, has also conducted research in fractal point processes in physical and biological systems, quantum optics, and photonics.