title: Ultra-High Field MRI Post Mortem Structural Connectivity of the Human Subthalamic Nucleus, Substantia Nigra, and Globus Pallidus.
abstract: BACKGROUND
  The subthalamic nucleus, substantia nigra, and globus pallidus, three nuclei of the human basal ganglia, play an important role in motor, associative, and limbic processing. The network of the basal ganglia is generally characterized by a direct, indirect, and hyperdirect pathway. This study aims to investigate the mesoscopic nature of these connections between the subthalamic nucleus, substantia nigra, and globus pallidus and their surrounding structures.
  
  
  METHODS
  A human post mortem brain specimen including the substantia nigra, subthalamic nucleus, and globus pallidus was scanned on a 7 T MRI scanner. High resolution diffusion weighted images were used to reconstruct the fibers intersecting the substantia nigra, subthalamic nucleus, and globus pallidus. The course and density of these tracks was analyzed.
  
  
  RESULTS
  Most of the commonly established projections of the subthalamic nucleus, substantia nigra, and globus pallidus were successfully reconstructed. However, some of the reconstructed fiber tracks such as the connections of the substantia nigra pars compacta to the other included nuclei and the connections with the anterior commissure have not been shown previously. In addition, the quantitative tractography approach showed a typical degree of connectivity previously not documented. An example is the relatively larger projections of the subthalamic nucleus to the substantia nigra pars reticulata when compared to the projections to the globus pallidus internus.
  
  
  CONCLUSIONS
  This study shows that ultra-high field post mortem tractography allows for detailed 3D reconstruction of the projections of deep brain structures in humans. Although the results should be interpreted carefully, the newly identified connections contribute to our understanding of the basal ganglia.
authors.affiliation: Department of Biomedical Image Analysis, Eindhoven University of TechnologyEindhoven, Netherlands; Department of Translational Neuroscience, Maastricht UniversityMaastricht, Netherlands.
authors.forename: Birgit R
authors.initials: BR
authors.lastname: Plantinga
authors.affiliation: Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Alard
authors.initials: A
authors.lastname: Roebroeck
authors.affiliation: Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Valentin G
authors.initials: VG
authors.lastname: Kemper
authors.affiliation: Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Kâmil
authors.initials: K
authors.lastname: Uludağ
authors.affiliation: Department of Translational Neuroscience, Maastricht University Maastricht, Netherlands.
authors.forename: Maartje
authors.initials: M
authors.lastname: Melse
authors.affiliation: Department of Neuroanatomy, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mai
authors.affiliation: Department of Neurology, Maastricht University Medical Center Maastricht, Netherlands.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Kuijf
authors.affiliation: Department of Anatomy and Embryology, Maastricht University Maastricht, Netherlands.
authors.forename: Andreas
authors.initials: A
authors.lastname: Herrler
authors.affiliation: Department of Neurosurgery, Maastricht University Medical Center Maastricht, Netherlands.
authors.forename: Ali
authors.initials: A
authors.lastname: Jahanshahi
authors.affiliation: Department of Biomedical Image Analysis, Eindhoven University of Technology Eindhoven, Netherlands.
authors.forename: Bart M
authors.initials: BM
authors.lastname: Ter Haar Romeny
authors.affiliation: Department of Translational Neuroscience, Maastricht UniversityMaastricht, Netherlands; Department of Neurosurgery, Maastricht University Medical CenterMaastricht, Netherlands.
authors.forename: Yasin
authors.initials: Y
authors.lastname: Temel
keywords: globus pallidus; post mortem; substantia nigra; subthalamic nucleus; tractography; ultra-high field MRI