title: Diffusion spectrum imaging shows the structural basis of functional cerebellar circuits in the human cerebellum in vivo.
abstract: BACKGROUND
  The cerebellum is a complex structure that can be affected by several congenital and acquired diseases leading to alteration of its function and neuronal circuits. Identifying the structural bases of cerebellar neuronal networks in humans in vivo may provide biomarkers for diagnosis and management of cerebellar diseases.
  
  
  OBJECTIVE
  To define the anatomy of intrinsic and extrinsic cerebellar circuits using high-angular resolution diffusion spectrum imaging (DSI).
  
  
  METHODS
  We acquired high-resolution structural MRI and DSI of the cerebellum in four healthy female subjects at 3T. DSI tractography based on a streamline algorithm was performed to identify the circuits connecting the cerebellar cortex with the deep cerebellar nuclei, selected brainstem nuclei, and the thalamus.
  
  
  RESULTS
  Using in-vivo DSI in humans we were able to demonstrate the structure of the following cerebellar neuronal circuits: (1) connections of the inferior olivary nucleus with the cerebellar cortex, and with the deep cerebellar nuclei (2) connections between the cerebellar cortex and the deep cerebellar nuclei, (3) connections of the deep cerebellar nuclei conveyed in the superior (SCP), middle (MCP) and inferior (ICP) cerebellar peduncles, (4) complex intersections of fibers in the SCP, MCP and ICP, and (5) connections between the deep cerebellar nuclei and the red nucleus and the thalamus.
  
  
  CONCLUSIONS
  For the first time, we show that DSI tractography in humans in vivo is capable of revealing the structural bases of complex cerebellar networks. DSI thus appears to be a promising imaging method for characterizing anatomical disruptions that occur in cerebellar diseases, and for monitoring response to therapeutic interventions.
authors.affiliation: Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Cristina.Granziera@chuv.ch
authors.forename: Cristina
authors.initials: C
authors.lastname: Granziera
authors.forename: Jeremy Dan
authors.initials: JD
authors.lastname: Schmahmann
authors.forename: Nouchine
authors.initials: N
authors.lastname: Hadjikhani
authors.forename: Heiko
authors.initials: H
authors.lastname: Meyer
authors.forename: Reto
authors.initials: R
authors.lastname: Meuli
authors.forename: Van
authors.initials: V
authors.lastname: Wedeen
authors.forename: Gunnar
authors.initials: G
authors.lastname: Krueger