Data from: Concurrent temporal channels for auditory processing: oscillatory neural entrainment reveals segregation of function at different scales

Natural sounds convey perceptually relevant information over multiple
timescales, and the necessary extraction of multi-timescale information
requires the auditory system to work over distinct ranges. The simplest
hypothesis suggests that temporal modulations are encoded in an equivalent
manner within a reasonable intermediate range. We show that the human
auditory system selectively and preferentially tracks acoustic dynamics
concurrently at 2 timescales corresponding to the neurophysiological theta
band (4–7 Hz) and gamma band ranges (31–45 Hz) but, contrary to
expectation, not at the timescale corresponding to alpha (8–12 Hz), which
has also been found to be related to auditory perception. Listeners heard
synthetic acoustic stimuli with temporally modulated structures at 3
timescales (approximately 190-, approximately 100-, and approximately
30-ms modulation periods) and identified the stimuli while undergoing
magnetoencephalography recording. There was strong intertrial phase
coherence in the theta band for stimuli of all modulation rates and in the
gamma band for stimuli with corresponding modulation rates. The alpha band
did not respond in a similar manner. Classification analyses also revealed
that oscillatory phase reliably tracked temporal dynamics but not
equivalently across rates. Finally, mutual information analyses
quantifying the relation between phase and cochlear-scaled correlations
also showed preferential processing in 2 distinct regimes, with the alpha
range again yielding different patterns. The results support the
hypothesis that the human auditory system employs (at least) a 2-timescale
processing mode, in which lower and higher perceptual sampling scales are
segregated by an intermediate temporal regime in the alpha band that
likely reflects different underlying computations.