title: Changes in resting-state brain networks in writer's cramp.
abstract: OBJECTIVE
  Writer's cramp (WC) is characterized by excessive cocontractions of agonist and antagonist hand and forearm muscles during writing. Changes in functional magnetic resonance imaging activation patterns in such conditions can be ambiguous as they might either reflect some aspect of the primary pathophysiological mechanism or, alternatively, may be the result of adaptive actions during task execution. To circumvent this problem, we examined WC patients during rest, i.e., without a task, using independent component analysis (ICA) applied to the blood oxygen level-dependent time series.
  
  
  METHODS
  Functionally connected brain networks during rest were defined by ICA to assess differences between WC patients (n = 16) and healthy controls (n = 16). Analysis was carried out using FMRIB's Software Library.
  
  
  RESULTS
  Two functional networks showed between-group differences, the sensorimotor network and the default-mode network. In WC patients, the connectivity was reduced in the left postcentral area and increased in basal ganglia in contrast to healthy controls. These changes were not reversed after treatment with botulinum toxin.
  
  
  CONCLUSIONS
  In line with other studies, the results show a dysfunction in cortico-subcortical circuits in WC involving somatosensory cortex, areas interfacing the sensory and motor systems, and putamen contralateral to symptomatic hand.
authors.affiliation: Department of Neurology, University of Lübeck, Lübeck, Germany. bahram.mohammadi@neuro.uni-luebeck.de
authors.forename: Bahram
authors.initials: B
authors.lastname: Mohammadi
authors.forename: Katja
authors.initials: K
authors.lastname: Kollewe
authors.forename: Amir
authors.initials: A
authors.lastname: Samii
authors.forename: Christian F
authors.initials: CF
authors.lastname: Beckmann
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dengler
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Münte
mesh_terms: D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D020821:Dystonic Disorders / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000294:innervation / Q000503:physiopathology; D006225:Hand / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D012146:Rest