title: The "handwriting brain": a meta-analysis of neuroimaging studies of motor versus orthographic processes.
abstract: BACKGROUND
  Handwriting is a modality of language production whose cerebral substrates remain poorly known although the existence of specific regions is postulated. The description of brain damaged patients with agraphia and, more recently, several neuroimaging studies suggest the involvement of different brain regions. However, results vary with the methodological choices made and may not always discriminate between "writing-specific" and motor or linguistic processes shared with other abilities.
  
  
  METHODS
  We used the "Activation Likelihood Estimate" (ALE) meta-analytical method to identify the cerebral network of areas commonly activated during handwriting in 18 neuroimaging studies published in the literature. Included contrasts were also classified according to the control tasks used, whether non-specific motor/output-control or linguistic/input-control. These data were included in two secondary meta-analyses in order to reveal the functional role of the different areas of this network.
  
  
  RESULTS
  An extensive, mainly left-hemisphere network of 12 cortical and sub-cortical areas was obtained; three of which were considered as primarily writing-specific (left superior frontal sulcus/middle frontal gyrus area, left intraparietal sulcus/superior parietal area, right cerebellum) while others related rather to non-specific motor (primary motor and sensorimotor cortex, supplementary motor area, thalamus and putamen) or linguistic processes (ventral premotor cortex, posterior/inferior temporal cortex).
  
  
  CONCLUSIONS
  This meta-analysis provides a description of the cerebral network of handwriting as revealed by various types of neuroimaging experiments and confirms the crucial involvement of the left frontal and superior parietal regions. These findings provide new insights into cognitive processes involved in handwriting and their cerebral substrates.
authors.affiliation: INSERM, Imagerie Cérébrale et Handicaps Neurologiques UMRS 825, Toulouse, France; Université de Toulouse, UPS, Imagerie Cérébrale et Handicaps Neurologiques UMRS 825, CHU Purpan, Toulouse, France; URI Octogone (EA 4156), Université Toulouse II Le Mirail, Toulouse, France. Electronic address: samuel.planton@inserm.fr.
authors.forename: Samuel
authors.initials: S
authors.lastname: Planton
authors.forename: Mélanie
authors.initials: M
authors.lastname: Jucla
authors.forename: Franck-Emmanuel
authors.initials: FE
authors.lastname: Roux
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Démonet
mesh_terms: D000381:Agraphia / Q000503:physiopathology; D001288:Attention / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D002531:Cerebellum / Q000502:physiology; D003627:Data Interpretation, Statistical; D005625:Frontal Lobe / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006236:Handwriting; D006801:Humans; D008606:Mental Processes / Q000502:physiology*; D008959:Models, Neurological; D009048:Motor Skills / Q000502:physiology*; D059906:Neuroimaging / Q000379:methods*; D009801:Oculomotor Muscles / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology
keywords: Functional neuroimaging; Handwriting; Meta-analysis; Spelling