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Strong Functional Connectivity among Homotopic Brain Areas Is Vital for Motor Control in Unilateral Limb Movement.

ABSTRACT: The mechanism underlying brain region organization for motor control in humans remains poorly understood. In this functional magnetic resonance imaging (fMRI) study, right-handed volunteers were tasked to maintain unilateral foot movements on the right and left sides as consistently as possible. We aimed to identify the similarities and differences between brain motor networks of the two conditions. We recruited 18 right-handed healthy volunteers aged 25 ± 2.3 years and used a whole-body 3T system for magnetic resonance (MR) scanning. Image analysis was performed using SPM8, Conn toolbox and Brain Connectivity Toolbox. We determined a craniocaudally distributed, mirror-symmetrical modular structure. The functional connectivity between homotopic brain areas was generally stronger than the intrahemispheric connections, and such strong connectivity led to the abovementioned modular structure. Our findings indicated that the interhemispheric functional interaction between homotopic brain areas is more intensive than the interaction along the conventional top-down and bottom-up pathways within the brain during unilateral limb movement. The detected strong interhemispheric horizontal functional interaction is an important aspect of motor control but often neglected or underestimated. The strong interhemispheric connectivity may explain the physiological phenomena and effects of promising therapeutic approaches. Further accurate and effective therapeutic methods may be developed on the basis of our findings.

SUBMITTER: Wei P

PROVIDER: S-EPMC5506200 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Strong Functional Connectivity among Homotopic Brain Areas Is Vital for Motor Control in Unilateral Limb Movement.

Wei Pengxu P Zhang Zuting Z Lv Zeping Z Jing Bin B

Frontiers in human neuroscience 20170712

The mechanism underlying brain region organization for motor control in humans remains poorly understood. In this functional magnetic resonance imaging (fMRI) study, right-handed volunteers were tasked to maintain unilateral foot movements on the right and left sides as consistently as possible. We aimed to identify the similarities and differences between brain motor networks of the two conditions. We recruited 18 right-handed healthy volunteers aged 25 ± 2.3 years and used a whole-body 3T syst ...[more]

PMID: 28747880

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Project description:BackgroundConstraint-induced movement therapy (CIMT) is a prominent neurorehabilitation approach for improving affected upper extremity motor function in children with unilateral cerebral palsy (UCP). However, the restraint of the less-affected upper extremity and intensive training protocol during CIMT may decrease children's motivation and increase the therapist's workload and family's burden. A kinect-based CIMT program, aiming to mitigate the concerns of CIMT, has been developed. The preliminary results demonstrated that this program was child-friendly and feasible for improving upper extremity motor function. However, whether the kinect-based CIMT can achieve better or at least comparable effects to that of traditional CIMT (i.e., therapist-based CIMT) should be further investigated. Therefore, this study aimed to compare the effects of kinect-based CIMT with that of therapist-based CIMT on upper extremity and trunk motor control and on daily motor function in children with UCP.MethodsTwenty-nine children with UCP were recruited and randomly allocated to kinect-based CIMT (n = 14) or therapist-based CIMT (n = 15). The intervention dosage was 2.25 h a day, 2 days a week for 8 weeks. Outcome measures, namely upper extremity and trunk motor control and daily motor function, were evaluated before and after 36-h interventions. Upper extremity and trunk motor control were assessed with unimanual reach-to-grasp kinematics, and daily motor function was evaluated with the Revised Pediatric Motor Activity Log. Between-group comparisons of effectiveness on all outcome measures were analyzed by analysis of covariance (α = 0.05).ResultsThe two groups demonstrated similar improvements in upper extremity motor control and daily motor function. In addition, the kinect-based CIMT group demonstrated greater improvements in trunk motor control than the therapist-based CIMT group did (F(1,28) > 4.862, p < 0.036).ConclusionKinect-based CIMT has effects comparable to that of therapist-based CIMT on UE motor control and daily motor function. Moreover, kinect-based CIMT helps decrease trunk compensation during reaching in children with UCP. Therefore, kinect-based CIMT can be used as an alternative approach to therapist-based CIMT.Trial registrationClinicalTrials.gov Identifier: NCT02808195. Registered on 2016/06/21, https://clinicaltrials.gov/ct2/show/NCT02808195 .

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Project description:BackgroundStroke rehabilitation may be improved with a better understanding of the contribution of ipsilateral motor pathways to the paretic limb and alterations in transcallosal inhibition. Few studies have evaluated these factors during dynamic, bilateral lower limb movements, and it is unclear whether they relate to functional outcomes.ObjectiveDetermine if lower limb ipsilateral excitability and transcallosal inhibition after stroke depend on target limb, task, or number of limbs involved, and whether these factors are related to clinical measures.MethodsIn 29 individuals with stroke, ipsilateral and contralateral responses to transcranial magnetic stimulation were measured in the paretic and nonparetic tibialis anterior during dynamic (unilateral or bilateral ankle dorsiflexion/plantarflexion) and isometric (unilateral dorsiflexion) conditions. Relative ipsilateral excitability and transcallosal inhibition were assessed. Fugl-Meyer, ankle movement accuracy, and walking characteristics were assessed.ResultsRelative ipsilateral excitability was greater during dynamic than isometric conditions in the paretic limb (P ≤ .02) and greater in the paretic than the nonparetic limb during dynamic conditions (P ≤ .004). Transcallosal inhibition was greater in the ipsilesional than contralesional hemisphere (P = .002) and during dynamic than isometric conditions (P = .03). Greater ipsilesional transcallosal inhibition was correlated with better ankle movement accuracy (R2 = 0.18, P = .04). Greater contralateral excitability to the nonparetic limb was correlated with improved walking symmetry (R2 = 0.19, P = .03).ConclusionsIpsilateral pathways have increased excitability to the paretic limb, particularly during dynamic tasks. Transcallosal inhibition is greater in the ipsilesional than contralesional hemisphere and during dynamic than isometric tasks. Ipsilateral pathways and transcallosal inhibition may influence walking asymmetry and ankle movement accuracy.

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Strong Functional Connectivity among Homotopic Brain Areas Is Vital for Motor Control in Unilateral Limb Movement.

Publications

Strong Functional Connectivity among Homotopic Brain Areas Is Vital for Motor Control in Unilateral Limb Movement.

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