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Abstract

The supplementary motor area (SMA) is situated in the medial parts of Brodmann area (BA) 6 in the frontal lobe. This cortical area is not only involved in the planning and execution of motor sequences that require precise temporal ordering, it also engages in the perceptual processing of temporal information (Macar et al., 2006). Increasingly detailed descriptions of SMA functions are accompanied by a dissociation of at least two subregions along a rostrocaudal axis. This organization is mirrored in the connections from the SMA to the Basal ganglia (BG, Lehéricy et al., 2004). However, the more rostral pre-SMA is also connected to the nonmotor part of the cerebellar dentate nucleus and the prefrontal cortex, whereas the more caudal SMA proper is connected to the motor part of the dentate and the primary motor cortex (Picard and Strick, 2001; Akkal et al., 2007). These anatomical links to BG and cerebellar temporal processing systems (Buhusi and Meck, 2005) suggest that the SMA performs a general computation related to the temporal, i.e. rhythmic patterning of events, with the pre-SMA supporting perceptual and the SMA proper supporting productive rhythm processing. In line with this assumption, the current meta-analysis of imaging literature identified clusters of fMRI activation when relevant studies are grouped with respect to rhythmic perception or production of temporal structure.