Abstract: BACKGROUND: The subgenual cingulate gyrus (SCG) has been proposed as a target for
deep brain stimulation (DBS) in neuropsychiatric disorders, mainly major depression.
Despite promising clinical results, the mechanism of action of DBS in this region is poorly
understood. Knowledge of the connections of the SCG can elucidate the network involved
by DBS in this area and can help refine the targeting for DBS electrode placement.
OBJECTIVE: To investigate the anatomic connections of the SCG region.
METHODS: An anatomic study of the connections of the SCG was performed on
postmortem specimens and in vivo with MR diffusion imaging tractography. Postmortem
dissections were performed according to the Klingler technique. Specimens
were fixed in 10% formalin and frozen at 215C for 2 weeks. After thawing, dissection
was performed with blunt dissectors. Whole brain tractography was performed using
spherical deconvolution tractography.
RESULTS: Four main connections were found: (1) fibers of the cingulum, originating at
the level of the SCG and terminating at the medial aspect of the temporal lobe (parahippocampal
gyrus); (2) fibers running toward the base of the frontal lobe, connecting
the SCG with frontopolar areas; (3) fibers running more laterally, converging onto the
ventral striatum (nucleus accumbens); (4) fibers of the uncinate fasciculus, connecting
the orbitofrontal with the anterior temporal region.
CONCLUSION: The SCG shows a wide range of white matter connections with limbic,
prefrontal, and mesiotemporal areas. These findings can help to explain the role of the
SCG in DBS for psychiatric disorders.
