The human auditory system^18 also contains a rich descending system that could mold
behaviourally significant sounds such as music.
This chapter considers temporal processing in humans relevant to musical processing. I
will consider functional imaging (using PET, fMRI, and MEG) and the psychophysical
assessment of patients with lesions. Functional imaging allows the determination of struc-
tures normally involvedin temporal analysis, and patient studies allow inference about the
necessarystructures for temporal analysis. For discussion of the extension of this approach
above the level of acoustic pattern analysis, I refer the reader to Chapter 16 by Zatorre in
this volume.Lesion studies
Fine temporal structure
There have been a number of studies suggesting that the detection of sounds of different
frequencies (as measured in the routine pure tone audiogram) depends on an intact170 Figure 11.2 Simplified representation of ascending auditory pathway to the auditory cortex. This is based on
animal and human studies (e.g. Refs 18 and 34) and demonstrates extensive processing of auditory information
before the cortex is reached. For clarity, only the convergence of the input from both ears at the right-sided brain
stem auditory nucleii is shown. A dorsal pathway, via the dorsal cochlear nucleus (DCN) and inferior colliculus
(IC) is shown, which is involved in animals in the analysis of spectrally complex waveforms. The diagram also
shows a ventral pathway, via the ventral cochlear nucleus (VCN), trapezoid body, and medial superior olive
(MSO), thought to be important in animals for the analysis of spatial information. LSOlateral superior olive,
MNTBmedial nucleus of the trapezoid body, MGBmedial geniculate body, SCsuperior colliculus.