Studies in non-human primates have shown that medial premotor projections to the striatum are characterized as a set of distinct circuits conveying different type of information. This study assesses the anatomical projections from the supplementary motor area (SMA), pre-SMA and motor cortex (MC) to the human striatum using diffusion tensor imaging (DTI) axonal tracking. Eight right-handed volunteers were studied at 1.5 T using DTI axonal tracking. A connectivity matrix was computed, which tested for connections between cortical areas (MC, SMA and pre-SMA) and subcortical areas (posterior, middle and anterior putamen and the head of the caudate nucleus) in each hemisphere. Pre-SMA projections to the striatum were located rostral to SMA projections to the striatum. The SMA and the MC were similarly connected to the posterior and middle putamen and not to the anterior striatum. These data show that the MC and SMA have connections with similar parts of the sensorimotor compartment of the human striatum, whereas the pre-SMA sends connections to more rostral parts of the striatum, including the associative compartment.
Bibliographical noteFunding Information:
This study was supported by grants from NIH (NS44825), BTRR P41-RR008079, the Keck Foundation, the Human Frontiers Science Program, PHRC AOR01109 and ACI 2001.
- Basal ganglia
- Diffusion tensor imaging
- Fiber tracking
- Supplementary motor area