Chris Plack, University of Manchester
Temporal fluctuations in sounds are represented by the synchronized firing patterns of neurons in the auditory nerve and auditory brainstem. These patterns can be measured in humans using electroencephalography, and are reflected in a sustained response called the frequency-following response (FFR). When two musical notes with simple frequency ratios are played simultaneously the resulting musical chord is pleasing and evokes a sense of resolution or consonance. Complex frequency ratios, on the other hand, evoke feelings of tension or dissonance. Consonance and dissonance form the basis of harmony, a central component of Western music. We have shown that musical harmony is well represented in the FFR, and that individual differences in the perception of musical harmony are related to individual differences in neural temporal coding. Harmony perception declines with age, and again this is reflected in FFR. The deterioration may be related to the loss and/or dysfunction of neurons in the auditory system, even for listeners with clinically normal hearing.