Investigations of the functional organization of human auditory cortex typically examine responses to different sound categories. An alternative approach is to characterize sounds with respect to their amount of variation in the time and frequency domains (i.e., spectral and temporal complexity). Although the vast majority of published studies examine contrasts between discrete sound categories, an alternative complexity-based taxonomy can be evaluated through meta-analysis. In a quantitative meta-analysis of 58 auditory neuroimaging studies, we examined the evidence supporting current models of functional specialization for auditory processing using grouping criteria based on either categories or spectro-temporal complexity. Consistent with current models, analyses based on typical sound categories revealed hierarchical auditory organization and left-lateralized responses to speech sounds, with high speech sensitivity in the left anterior superior temporal cortex. Classification of contrasts based on spectro-temporal complexity, on the other hand, revealed a striking within-hemisphere dissociation in which caudo-lateral temporal regions in auditory cortex showed greater sensitivity to spectral changes, while anterior superior temporal cortical areas were more sensitive to temporal variation, consistent with recent findings in animal models. The meta-analysis thus suggests that spectro-temporal acoustic complexity represents a useful alternative taxonomy to investigate the functional organization of human auditory cortex.
Keywords: fMRI, category, time, frequency, hierarchy
Citation: Samson F, Zeffiro TA, Toussaint A and Belin P (2011) Stimulus complexity and categorical effects in human auditory cortex: an Activation Likelihood Estimation meta-analysis. Front. Psychology 1:241. doi: 10.3389/fpsyg.2010.00241
Received: 16 September 2010;
Accepted: 23 December 2010;
Published online: 17 January 2011.
Edited by:Josef P. Rauschecker, Georgetown University School of Medicine, USA
Reviewed by:Jonas Obleser, Max Planck Institute for Human Cognitive and Brain Sciences, Germany
Copyright: © 2011 Samson, Zeffiro, Toussaint and Belin. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
*Correspondence: Fabienne Samson, Hôpital Rivière-des-Prairies, Recherche TN, 7070 Boulevard Perras, Montréal, QC, Canada H1E 1A4. e-mail: firstname.lastname@example.org