These "novelty detector neurons" quickly stop firing if a sound or sound pattern is repeated, but will briefly resume firing whenever some aspect of the sound changes, according to Ellen Covey, one of the authors of the study and a psychology professor at the University of Washington. The neurons can detect changes in the pitch, loudness or duration of a single sound and can even detect changes in the pattern of a complex series of sounds, she said.
Covey and her colleagues, Dr. Manuel Malmierca of the University of Salamanca and doctoral student David Perez-Gonzalez, who is currently a visiting scientist in the UW psychology department, report their findings in the early December issue of the European Journal of Neuroscience.
The neurons are located under the cortex in a part of the brain called the inferior colliculus. Covey said the research implies that these cells can "remember a frequently occurring pattern and perform relatively sophisticated cognitive tasks such as discriminating a novel pattern from a frequently occurring one."
She said that, contrary to popular belief, the new findings suggest that some cognitive processes for sorting and identifying sounds occur very early in the auditory pathway, and that novelty detector neurons could be involved in directing attention to unexpected sounds, possibly evoking rapid reflex responses.
Novelty detector neurons seem to act as gatekeepers, preventing information about unimportant sounds from reaching the cortex, thus allowing people to ignore sounds that do not require attention.
"It is probably a good thing to have this ability because it allows us to tune out background noises like the humming of a car's motor while we are driving or the regular tick-to
Contact: Joel Schwarz
University of Washington