Regional heterogeneity in the processing and the production of speech in the human planum temporale.
BACKGROUND
The role of the left planum temporale (PT) in auditory language processing has been a central theme in cognitive neuroscience since the first descriptions of its leftward neuroanatomical asymmetry. While it is clear that PT contributes to auditory language processing there is still some uncertainty about its role in spoken language production.


METHODS
Here we examine activation patterns of the PT for speech production, speech perception and single word reading to address potential hemispheric and regional functional specialization in the human PT. To this aim, we manually segmented the left and right PT in three non-overlapping regions (medial, lateral and caudal PT) and examined, in two complementary experiments, the contribution of exogenous and endogenous auditory input on PT activation under different speech processing and production conditions.


RESULTS
Our results demonstrate that different speech tasks are associated with different regional functional activation patterns of the medial, lateral and caudal PT. These patterns are similar across hemispheres, suggesting bilateral processing of the auditory signal for speech at the level of PT.


CONCLUSIONS
Results of the present studies stress the importance of considering the anatomical complexity of the PT in interpreting fMRI data.
Center for Mind & Brain Sciences (CIMeC), The University of Trento, Italy. Electronic address: Pascale.Tremblay@fmed.ulaval.ca.
Pascale
P
Tremblay
Isabelle
I
Deschamps
Vincent L
VL
Gracco
D000328:Adult; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D059907:Functional Neuroimaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D013060:Speech / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*