Complex motor task associated with non-linear BOLD responses in cerebro-cortical areas and cerebellum.
Previous studies have used fMRI to address the relationship between grip force (GF) applied to an object and BOLD response. However, whilst the majority of these studies showed a linear relationship between GF and neural activity in the contralateral M1 and ipsilateral cerebellum, animal studies have suggested the presence of non-linear components in the GF-neural activity relationship. Here, we present a methodology for assessing non-linearities in the BOLD response to different GF levels, within primary motor as well as sensory and cognitive areas and the cerebellum. To be sensitive to complex forms, we designed a feasible grip task with five GF targets using an event-related visually guided paradigm and studied a cohort of 13 healthy volunteers. Polynomial functions of increasing order were fitted to the data.



(1) activated motor areas irrespective of GF; (2) positive higher-order responses in and outside M1, involving premotor, sensory and visual areas and cerebellum; (3) negative correlations with GF, predominantly involving the visual domain. Overall, our results suggest that there are physiologically consistent behaviour patterns in cerebral and cerebellar cortices; for example, we observed the presence of a second-order effect in sensorimotor areas, consistent with an optimum metabolic response at intermediate GF levels, while higher-order behaviour was found in associative and cognitive areas. At higher GF levels, sensory-related cortical areas showed reduced activation, interpretable as a redistribution of the neural activity for more demanding tasks. These results have the potential of opening new avenues for investigating pathological mechanisms of neurological diseases.
NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK. adnan.alahmadi.11@ucl.ac.uk.|Department of Diagnostic Radiology, Faculty of Applied Medical Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia. adnan.alahmadi.11@ucl.ac.uk.
Adnan A S
AA
Alahmadi
NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.
Rebecca S
RS
Samson
Department of Neuroimaging, Institute of Psychiatry, King's College London, London, UK.
David
D
Gasston
NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.|Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
Matteo
M
Pardini
Wellcome Centre for Imaging Neuroscience, UCL Institute of Neurology, University College London, London, UK.
Karl J
KJ
Friston
Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy.|Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.
Egidio
E
D'Angelo
NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.|Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, UK.
Ahmed T
AT
Toosy
NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.|Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy.
Claudia A M
CA
Wheeler-Kingshott
D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002531:Cerebellum / Q000098:blood supply* / Q000502:physiology*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000502:physiology*; D005260:Female; D018737:Hand Strength; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009043:Motor Activity; D009044:Motor Cortex / Q000098:blood supply / Q000502:physiology; D009434:Neural Pathways / Q000098:blood supply / Q000502:physiology; D017711:Nonlinear Dynamics; D010296:Parietal Lobe / Q000098:blood supply / Q000502:physiology; D014793:Visual Cortex / Q000098:blood supply / Q000502:physiology; D055815:Young Adult
Force; MVC; Power grip; Visuomotor task; fMRI