title: Bottom-up and top-down processes in body representation: a study of brain-damaged and amputee patients.
abstract: OBJECTIVE
  Body representation is a complex process involving different sources of top-down and bottom-up information. Processing the position and the relations among different body parts is necessary to build up a specific body representation, that is, the visuospatial body map (or topological map of the body). Here we aimed to investigate how the loss of peripheral or central information affects this representation by testing amputee and brain-damaged patients.
  
  
  METHODS
  Thirty-two unilateral brain-damaged patients (i.e., left-brain-damaged patients and right-brain-damaged patients who were or were not affected by personal neglect), 18 lower limb amputees and 15 healthy controls took part in the study. The topological body map was assessed by means of the "Frontal body-evocation subtest" (Daurat-Hmeljiak, Stambak, & Berges, 1978), in which participants have to put tiles (each representing a body part) on a small wooden board on which a head is depicted.
  
  
  RESULTS
  Group statistical analysis showed that in amputee patients the loss of peripheral information about the right lower limb affects the ability to represent relations among different body parts as much as the loss of top-down information in brain-damaged patients with personal neglect. Single case analysis of brain-damaged patients without personal neglect showed that the topological map of the body was deficient in 1 right-brain-damaged and 2 left-brain-damaged patients.
  
  
  CONCLUSIONS
  Studying amputee and brain-damaged patients together allowed us to highlight the importance of visuospatial information about one's own limbs and the role of both hemispheres (not only the left one) in creating an efficient topological body representation.
authors.affiliation: Department of Psychology, Sapienza University of Rome and IRCCS Santa Lucia Foundation.
authors.forename: Liana
authors.initials: L
authors.lastname: Palermo
authors.affiliation: IRCCS Santa Lucia Foundation.
authors.forename: Antonella
authors.initials: A
authors.lastname: Di Vita
authors.affiliation: Life, Health and Environmental Science Department, L'Aquila University.
authors.forename: Laura
authors.initials: L
authors.lastname: Piccardi
authors.affiliation: IRCCS Santa Lucia Foundation.
authors.forename: Marco
authors.initials: M
authors.lastname: Traballesi
authors.affiliation: Department of Psychology, Sapienza University of Rome.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Guariglia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000674:Amputees / Q000523:psychology*; D001828:Body Image; D001930:Brain Injuries / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D008875:Middle Aged; D009483:Neuropsychological Tests; D013028:Space Perception; D014796:Visual Perception