The ASHA Leader, June 2015, Vol. 20, 16. doi:10.1044/leader.RIB3.20062015.16
Brain cells may be able to “wait” to determine what we hear, according to new research on gerbils at the Laboratory for Auditory Neurophysiology in Leuven, Belgium.
Human ears locate sounds in space by accounting for differences in intensity and timing between signals that reach our two ears. Cells in the brainstem, which receive electrical pulses from the auditory nerve when the cochlea hears sound, are “hyper-specialized” to respond to certain time differences, according to the lab’s Philip X. Joris, who worked with lead author Tom P. Franken on the study, published in Nature Neuroscience.
“For example, one cell may respond to sounds right in front of us, which reach both ears at the same time, while another cell may respond to sounds to our side, which reach the ears with a time difference of half a millisecond,” Joris says. “Depending on which cell is active, we know where the sound source is in space. But how cells compute this time difference has been a matter of conjecture because it is exceedingly difficult to study these cells in the brainstem.”
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