title: The neural correlates of self-paced finger tapping in bipolar depression with motor retardation.
abstract: OBJECTIVE
  Motor retardation is a characteristic feature of bipolar depression, and is also a core feature of Parkinson's disease. Within the framework of the functional deafferentiation theory in Parkinson's disease, we hypothesised that motor retardation in bipolar depression is mediated by disrupted subcortical activation, leading to decreased activation of cortical motor areas during finger tapping.
  
  
  METHODS
  We used functional magnetic resonance imaging to investigate neural activity during self-paced finger tapping to elucidate whether brain regions that mediate preparation, control and execution of movement are activated differently in subjects with bipolar depression (n = 9) compared to healthy controls (n = 12).
  
  
  RESULTS
  An uncorrected whole-brain analysis revealed significant group differences in dorsolateral and ventromedial prefrontal cortex. Corrected analyses showed non-significant differences in patients compared to controls: decreased and less widespread activation of the left putamen and left pallidum; increased activity in the left thalamus and supplementary motor area; decreased activation in the left lateral pre- and primary motor cortices; absence of activation in the pre-supplementary motor area; activation of the bilateral rostral cingulate motor area.
  
  
  CONCLUSIONS
  Both movement preparation and execution may be affected in motor retardation, and the activity in the whole left-side motor circuit is altered during self-initiated motor performance in bipolar depression.
authors.affiliation: 1 Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Benny
authors.initials: B
authors.lastname: Liberg
authors.affiliation: 1 Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Adler
authors.affiliation: 2 Department of Diagnostic Medical Physics, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Jonsson
authors.affiliation: 1 Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Landén
authors.affiliation: 1 Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Rahm
authors.affiliation: 4 Department of Neurobiology, Care Sciences and Society, Division of Clinical Geriatrics, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
authors.affiliation: 5 Department of Clinical Science, Intervention and Technology, Division of Medical Imaging and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Kristoffersen-Wiberg
authors.affiliation: 1 Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Wahlund