title: Dynamics of functional and effective connectivity within human cortical motor control networks.
abstract: OBJECTIVE
  Praxis, the performance of complex motor gestures, is crucial to the development of motor and social/communicative capacities. Praxis relies on a network consisting of inferior parietal and premotor regions, particularly on the left, and is thought to require transformation of spatio-temporal representations (parietal) into movement sequences (premotor).
  
  
  METHODS
  We examined praxis network dynamics by measuring EEG effective connectivity while healthy subjects performed a praxis task.
  
  
  RESULTS
  Propagation from parietal to frontal regions was not statistically greater on the left than the right. However, propagation from left parietal regions to all other regions was significantly greater during gesture preparation than execution. Moreover, during gesture preparation only, propagation from the left parietal region to bilateral frontal regions was greater than reciprocal propagations to the left parietal region. This directional specificity was not observed for the right parietal region.
  
  
  CONCLUSIONS
  These findings represent direct electrophysiological evidence for directionally predominant propagation in left frontal-parietal networks during praxis behavior, which may reflect neural mechanisms by which representations in the human brain select appropriate motor sequences for subsequent execution.
  
  
  CONCLUSIONS
  In addition to bolstering the classic view of praxis network function, these results also demonstrate the relevance of additional information provided by directed connectivity measures.
authors.affiliation: Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA. Electronic address: ewen@kennedykrieger.org.
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Ewen
authors.affiliation: Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD 21205, USA. Electronic address: lakshmanan@kennedykrieger.org.
authors.forename: Balaji M
authors.initials: BM
authors.lastname: Lakshmanan
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Building 10, Room 7D37, 10 Center Drive, MSC 1428, Bethesda, MD 20892-1428, USA. Electronic address: hallettm@ninds.nih.gov.
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA; Laboratory for Neurocognitive and Imaging Research, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA. Electronic address: mostofsky@kennedykrieger.org.
authors.forename: Stewart H
authors.initials: SH
authors.lastname: Mostofsky
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA. Electronic address: ncrone@jhmi.edu.
authors.forename: Nathan E
authors.initials: NE
authors.lastname: Crone
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA. Electronic address: akorzen@jhmi.edu.
authors.forename: Anna
authors.initials: A
authors.lastname: Korzeniewska
mesh_terms: D000328:Adult; D063132:Connectome; D005260:Female; D005868:Gestures; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills; D010296:Parietal Lobe / Q000502:physiology*
keywords: EEG; Effective connectivity; Efference copy; Praxis