title: Neural correlates of finger gnosis.
abstract: Neuropsychological studies have described patients with a selective impairment of finger identification in association with posterior parietal lesions. However, evidence of the role of these areas in finger gnosis from studies of the healthy human brain is still scarce. Here we used functional magnetic resonance imaging to identify the brain network engaged in a novel finger gnosis task, the intermanual in-between task (IIBT), in healthy participants. Several brain regions exhibited a stronger blood oxygenation level-dependent (BOLD) response in IIBT than in a control task that did not explicitly rely on finger gnosis but used identical stimuli and motor responses as the IIBT. The IIBT involved stronger signal in the left inferior parietal lobule (IPL), bilateral precuneus (PCN), bilateral premotor cortex, and left inferior frontal gyrus. In all regions, stimulation of nonhomologous fingers of the two hands elicited higher BOLD signal than stimulation of homologous fingers. Only in the left anteromedial IPL (a-mIPL) and left PCN did signal strength decrease parametrically from nonhomology, through partial homology, to total homology with stimulation delivered synchronously to the two hands. With asynchronous stimulation, the signal was stronger in the left a-mIPL than in any other region, possibly indicating retention of task-relevant information. We suggest that the left PCN may contribute a supporting visuospatial representation via its functional connection to the right PCN. The a-mIPL may instead provide the core substrate of an explicit bilateral body structure representation for the fingers that when disrupted can produce the typical symptoms of finger agnosia.
authors.affiliation: Department of Neurosciences, University of Parma, I-43100 Parma, Italy, Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom, Division of Psychology, Abertay University, Dundee DD1 1HG, United Kingdom, elena.rusconi@gmail.com.
authors.forename: Elena
authors.initials: E
authors.lastname: Rusconi
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Tamè
authors.affiliation: Department of Psychology, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom.
authors.forename: Michele
authors.initials: M
authors.lastname: Furlan
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom.
authors.forename: Patrick
authors.initials: P
authors.lastname: Haggard
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy.
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Demarchi
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Adriani
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferrari
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy, MEG-Center, Werner Reichardt Centre for Integrative Neuroscience, Eberhard-Karls-University of Tübingen, D-72076 Tübingen, Germany, and Department of Psychology and Cognitive Science, University of Trento, I-38068 Rovereto, Italy.
authors.forename: Christoph
authors.initials: C
authors.lastname: Braun
authors.affiliation: Centre for Mind/Brain Sciences, University of Trento, I-38123 Mattarello, Italy, Department of Psychology and Cognitive Science, University of Trento, I-38068 Rovereto, Italy.
authors.forename: Jens
authors.initials: J
authors.lastname: Schwarzbach
mesh_terms: D000328:Adult; D000377:Agnosia / Q000503:physiopathology; D001828:Body Image; D001931:Brain Mapping; D004292:Dominance, Cerebral; D005260:Female; D005385:Fingers; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D012016:Reference Values; D055698:Touch Perception / Q000502:physiology
keywords: body structure representation; finger gnosis; intraparietal circuits