Differences in Connectivity Between the Anterior and Mediodorsal Nuclei of Thalamus in the Human Brain: Diffusion Tensor Tractography Study

Objectives: No study that compares the connectivity of the Anterior Nucleus (AN) and Mediodorsal Nucleus (MDN) has been reported yet. In the present study, we attempted to investigate differences in connectivity between the AN and MDN in the human brain, using probabilistic Diffusion Tensor Tractography (DTT). Methods: Forty-one healthy subjects were recruited for this present study. For connectivity of the AN and MDN, a seed region of interest was placed on the AN and MDN according to the known anatomical location using probabilistic DTT. Connectivity was defined as the incidence of connection between the AN/MDN and each brain region. Results: The AN showed high connectivity to the lateral prefrontal cortex (lPFC, 92.7%), ventromedial prefrontal cortex (vmPFC,91.5%), and orbitofrontal cortex (OFC,67.1%). The MDN showed high connectivity to the lPFC (86.6%), vmPFC (84.1%), primary motor cortex (M1, 73.2%), premotor cortex (PMC,72.0%), and OFC (53.7%). In comparison to the difference of connectivity, no difference in the lPFC, vmPFC, and OFC was observed between the AN and MDN. Conclusion: We found that both the AN and MDN showed high connectivity to the PFC. In addition, degree of connectivity from the AN and MDN to the PFC was similar.