A study published in the Jan. 2 issue of Nature found that, in auditory synaptic transmission, synaptic depression is used to compute sound levels and to correct neuronal signals in order to better locate the source of a sound in space. The study, published in the "Letters to Nature" section, was accompanied by a "News and Views" letter describing the significance of the findings.
In the study, researchers characterized synaptic depression at the synapse between neurons in the embryonic chick auditory brain stem using a biophysically realistic computer model of neurons from the nucleus laminaris.
All synapses exhibit depression, a decrease in strength after rapid, repeated use, and all synapses can increase or decrease synaptic strength depending on the history of synaptic use (short-term synaptic plasticity). Among other findings, researchers noted that depressed synapses could compensate for an increased amount of stimulation produced by loud sounds. This compensation could help animals pinpoint sound irrespective of intensity.
UW authors from the Department of Physiology and Biophysics include Daniel Cook, research professor, Peter Schwindt, professor emeritus, and William Spain, associate professor (joint appointment with neurology and research affiliate at the Virginia Merrill Bloedel Hearing Research Center). Third-year medical student Lucinda Grande was also an author.
February 7, 2003