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Motor imagery in amyotrophic lateral Sclerosis: An fMRI study of postural control.
Abidi, Malek Pradat, Pierre-Francois Termoz, Nicolas Couillandre, Annabelle Bede, Peter de Marco, Giovanni
Abidi, Malek
Pradat, Pierre-Francois
Termoz, Nicolas
Couillandre, Annabelle
Bede, Peter
de Marco, Giovanni
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Editors
Other Contributors
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Date
2022-05-17
Date Submitted
Keywords
ALS
Connectivity
DCM
Motor imagery
Neuroimaging
fMRI
Connectivity
DCM
Motor imagery
Neuroimaging
fMRI
Other Subjects
Subject Mesh
Planned Date
Start Date
Collaborators
Principal Investigators
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Abstract
BACKGROUND: The functional reorganization of brain networks sustaining gait is poorly characterized in amyotrophic lateral sclerosis (ALS) despite ample evidence of progressive disconnection between brain regions. The main objective of this fMRI study is to assess gait imagery-specific networks in ALS patients using dynamic causal modeling (DCM) complemented by parametric empirical Bayes (PEB) framework.
METHOD: Seventeen lower motor neuron predominant (LMNp) ALS patients, fourteen upper motor neuron predominant (UMNp) ALS patients and fourteen healthy controls participated in this study. Each subject performed a dual motor imagery task: normal and precision gait. The Movement Imagery Questionnaire (MIQ-rs) and imagery time (IT) were used to evaluate gait imagery in each participant. In a neurobiological computational model, the circuits involved in imagined gait and postural control were investigated by modelling the relationship between normal/precision gait and connection strengths.
RESULTS: Behavioral results showed significant increase in IT in UMNp patients compared to healthy controls (P < 0.05) and LMNp (P < 0.05). During precision gait, healthy controls activate the model's circuits involved in the imagined gait and postural control. In UMNp, decreased connectivity (inhibition) from basal ganglia (BG) to supplementary motor area (SMA) and from SMA to posterior parietal cortex (PPC) is observed. Contrary to healthy controls, DCM detects no cerebellar-PPC connectivity in neither UMNp nor LMNp ALS. During precision gait, bilateral connectivity (excitability) between SMA and BG is observed in the LMNp group contrary to UMNp and healthy controls.
CONCLUSIONS: Our findings demonstrate the utility of implementing both DCM and PEB to characterize connectivity patterns in specific patient phenotypes. Our approach enables the identification of specific circuits involved in postural deficits, and our findings suggest a putative excitatory-inhibitory imbalance. More broadly, our data demonstrate how clinical manifestations are underpinned by network-specific disconnection phenomena in ALS.
Language
en
Citation
ISSN
2213-1582
eISSN
ISBN
DOI
10.1016/j.nicl.2022.103051
PMID
35598461