Functional connectivity of the superior human temporal sulcus in the brain resting state at 3T.

INTRODUCTION: The superior temporal sulcus (STS) constitutes a polymodal associative area providing higher-order visual representation of other's action and emotion, necessary for imitation, empathizing, and mentalizing. In monkeys, STS is connected with the cerebellum, which is also involved in motor, emotional, and cognitive functions. However, in humans, very few data are available concerning the functional connectivity of polymodal STS in general and its functional links with the cerebellum, in particular. This study was therefore designed to investigate the intrinsically connected network of STS during the brain resting state with possible involvement of the cerebellum.

METHODS: Data from 14 right-handed healthy volunteers were acquired at rest and analyzed by region of interest (ROI)-based functional connectivity. Blood-oxygen-level-dependent (BOLD) signal fluctuations of separate six ROIs located in the right and left posterior, medial, and anterior STS were successively used to identify significant temporal correlations with BOLD signal fluctuations of other brain regions.

RESULTS: Low-frequency BOLD signals of the right and left posterior, medial, and lateral STS share a common bilateral circuit encompassing the ventrolateral prefrontal, premotor/motor, insular, parietal temporal, occipital, and cerebellar cortices (lobules VI/VIIA), thalamus, and striatum.

CONCLUSION: The STS-centered network (1) is intrinsically connected during the brain resting, (2) encompasses the whole caudalmost two thirds of STS, (3) may partly represent the whole STS structural connectivity, and includes the motor and cognitive neocerebellum (lobules VI/VIIA).