title: An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation.
abstract: Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson's disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson's disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment.
authors.affiliation: NIF - Neuroimagem Funcional, LIM44 - Laboratório de Investigação Médica 44 - LIM - 44, Department of Radiology, University of São Paulo, São Paulo, Brazil.
authors.forename: Andrea Cristina
authors.initials: AC
authors.lastname: de Lima-Pardini
authors.affiliation: NIF - Neuroimagem Funcional, LIM44 - Laboratório de Investigação Médica 44 - LIM - 44, Department of Radiology, University of São Paulo, São Paulo, Brazil.
authors.forename: Raymundo Machado
authors.initials: RM
authors.lastname: de Azevedo Neto
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Daniel Boari
authors.initials: DB
authors.lastname: Coelho
authors.affiliation: NIF - Neuroimagem Funcional, LIM44 - Laboratório de Investigação Médica 44 - LIM - 44, Department of Radiology, University of São Paulo, São Paulo, Brazil.
authors.forename: Catarina Costa
authors.initials: CC
authors.lastname: Boffino
authors.affiliation: Department of Psychosis Studies, King's College London, London, UK.
authors.forename: Sukhwinder S
authors.initials: SS
authors.lastname: Shergill
authors.affiliation: Movement Disorders Clinic, Department of Neurology, Hospital das Clínicas of the University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: de Oliveira Souza
authors.affiliation: Movement Disorders Clinic, Department of Neurology, Hospital das Clínicas of the University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Rachael
authors.initials: R
authors.lastname: Brant
authors.affiliation: Movement Disorders Clinic, Department of Neurology, Hospital das Clínicas of the University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Egberto Reis
authors.initials: ER
authors.lastname: Barbosa
authors.affiliation: NIF - Neuroimagem Funcional, LIM44 - Laboratório de Investigação Médica 44 - LIM - 44, Department of Radiology, University of São Paulo, São Paulo, Brazil.
authors.forename: Ellison Fernando
authors.initials: EF
authors.lastname: Cardoso
authors.affiliation: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Luis Augusto
authors.initials: LA
authors.lastname: Teixeira
authors.affiliation: Department of Psychology &Communication Studies, University of Idaho, Moscow, Idaho, USA.
authors.forename: Rajal G
authors.initials: RG
authors.lastname: Cohen
authors.affiliation: Department of Neurology, Oregon Health and Science University, Portland, Oregon, USA.
authors.forename: Fay Bahling
authors.initials: FB
authors.lastname: Horak
authors.affiliation: NIF - Neuroimagem Funcional, LIM44 - Laboratório de Investigação Médica 44 - LIM - 44, Department of Radiology, University of São Paulo, São Paulo, Brazil.
authors.forename: Edson
authors.initials: E
authors.lastname: Amaro
mesh_terms: D000368:Aged; D005260:Female; D005684:Gait; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055595:Mechanical Phenomena; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology*; D004856:Postural Balance