For a general discussion of neural correlates of music perception, check out the review by Koelsch et al (2005).
Menon et al (2002) provide a starting point for learning about neural correlates of timbre processing. I quote the abstract. But have a look at the article for more info
Timbre is a major structuring force in music and one of the most
important and ecologically relevant features of auditory events. We
used sound stimuli selected on the basis of previous
psychophysiological studies to investigate the neural correlates of
timbre perception. Our results indicate that both the left and right
hemispheres are involved in timbre processing, challenging the
conventional notion that the elementary attributes of musical
perception are predominantly lateralized to the right hemisphere.
Signiﬁcant timbre-related brain activation was found in well-de- ﬁned
regions of posterior Heschl’s gyrus and superior temporal sulcus,
extending into the circular insular sulcus. Although the extent of
activation was not signiﬁcantly different between left and right
hemispheres, temporal lobe activations were signiﬁcantly posterior in
the left, compared to the right, hemisphere, suggesting a functional
asymmetry in their respective contributions to timbre processing. The
implications of our ﬁndings for music processing in particular and
auditory processing in general are discussed.
Halpern et al (2004) provide another relevant study:
The generality of findings implicating secondary auditory areas in
auditory imagery was tested by using a timbre imagery task with fMRI.
Another aim was to test whether activity in supplementary motor area
(SMA) seen in prior studies might have been related to
subvocalization. Participants with moderate musical background were
scanned while making similarity judgments about the timbre of heard or
imagined musical instrument sounds. The critical control condition was
a visual imagery task. The pattern of judgments in perceived and
imagined conditions was similar, suggesting that perception and
imagery access similar cognitive representations of timbre. As
expected, judgments of heard timbres, relative to the visual imagery
control, activated primary and secondary auditory areas with some
right-sided asymmetry. Timbre imagery also activated secondary
auditory areas relative to the visual imagery control, although less
strongly, in accord with previous data. Significant overlap was
observed in these regions between perceptual and imagery conditions.
Because the visual control task resulted in deactivation of auditory
areas relative to a silent baseline, we interpret the timbre imagery
effect as a reversal of that deactivation. Despite the lack of an
obvious subvocalization component to timbre imagery, some activity in
SMA was observed, suggesting that SMA may have a more general role in
imagery beyond any motor component.
- Menon, V., Levitin, D. J., Smith, B. K., Lembke, A., Krasnow, B. D., Glazer, D., ... & McAdams, S. (2002). Neural correlates of timbre change in harmonic sounds. Neuroimage, 17(4), 1742-1754. PDF
- Halpern, A. R., Zatorre, R. J., Bouffard, M., & Johnson, J. A. (2004). Behavioral and neural correlates of perceived and imagined musical timbre. Neuropsychologia, 42(9), 1281-1292. PDF
- Koelsch, S., & Siebel, W. A. (2005). Towards a neural basis of music perception. Trends in cognitive sciences, 9(12), 578-584. Koelsch, S., & Siebel, W. A. (2005). Towards a neural basis of music perception. Trends in cognitive sciences, 9(12), 578-584. HTML