Asymmetric directed functional connectivity within the frontoparietal motor network during motor imagery and execution

Introduction. Sensorimotor cortex is activated similarly during motor execution and motor imagery. The study of functional connectivity networks (FCNs) aims at successfully modeling the dynamics of information flow between cortical areas.Materials and Methods. Seven healthy subjects performed 4 motor tasks (real foot, imaginary foot, real hand, and imaginary hand movements), while electroencephalography was recorded over the sensorimotor cortex. Event-Related Desynchronization/Synchronization (ERD/ERS) of the mu-rhythm was used to evaluate MI performance. Source detection and FCNs were studied with eConnectome.Results and Discussion. Four subjects produced similar ERD/ERS patterns between motor execution and imagery during both hand and foot tasks, 2 subjects only during hand tasks, and 1 subject only during foot tasks. All subjects showed the expected brain activation in well-performed MI tasks, facilitating cortical source estimation. Preliminary functional connectivity analysis shows formation of networks on the sensorimotor cortex during motor imagery and execution.Conclusions. Cortex activation maps depict sensorimotor cortex activation, while similar functional connectivity networks are formed in the sensorimotor cortex both during actual and imaginary movements. eConnectome is demonstrated as an effective tool for the study of cortex activation and FCN. The implementation of FCN in motor imagery could induce promising advancements in Brain Computer Interfaces.

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Functional Brain Connectivity during Multiple Motor Imagery Tasks in Spinal Cord Injury

Neural Plasticity ◽

10.1155/2018/9354207 ◽

2018 ◽

Vol 2018 ◽

pp. 1-20 ◽

Cited By ~ 2

Author(s):

Alkinoos Athanasiou ◽

Nikos Terzopoulos ◽

Niki Pandria ◽

Ioannis Xygonakis ◽

Nicolas Foroglou ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Functional Connectivity ◽

Motor Imagery ◽

Healthy Subjects ◽

Brain Connectivity ◽

Descending Pathways ◽

Brain Organization ◽

Sensorimotor Network ◽

Cord Injury

Reciprocal communication of the central and peripheral nervous systems is compromised during spinal cord injury due to neurotrauma of ascending and descending pathways. Changes in brain organization after spinal cord injury have been associated with differences in prognosis. Changes in functional connectivity may also serve as injury biomarkers. Most studies on functional connectivity have focused on chronic complete injury or resting-state condition. In our study, ten right-handed patients with incomplete spinal cord injury and ten age- and gender-matched healthy controls performed multiple visual motor imagery tasks of upper extremities and walking under high-resolution electroencephalography recording. Directed transfer function was used to study connectivity at the cortical source space between sensorimotor nodes. Chronic disruption of reciprocal communication in incomplete injury could result in permanent significant decrease of connectivity in a subset of the sensorimotor network, regardless of positive or negative neurological outcome. Cingulate motor areas consistently contributed the larger outflow (right) and received the higher inflow (left) among all nodes, across all motor imagery categories, in both groups. Injured subjects had higher outflow from left cingulate than healthy subjects and higher inflow in right cingulate than healthy subjects. Alpha networks were less dense, showing less integration and more segregation than beta networks. Spinal cord injury patients showed signs of increased local processing as adaptive mechanism. This trial is registered with NCT02443558.

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Current knowledge on selected rehabilitative methods used in post-stroke recovery

Rehabilitacja Medyczna ◽

10.5604/01.3001.0011.6823 ◽

2018 ◽

Vol 21 (3) ◽

pp. 51-57

Author(s):

Pawel Kiper ◽

Aneta Pirowska ◽

Joanna Stożek ◽

Alfonc Baba ◽

Michela Agostini ◽

...

Keyword(s):

Motor Imagery ◽

Brain Plasticity ◽

Current Knowledge ◽

Stroke Recovery ◽

Active Movement ◽

Phantom Pain ◽

Mirror Therapy ◽

Therapeutic Modalities ◽

Constraint Induced Movement Therapy ◽

Motor Network

Understanding brain plasticity after stroke is important in developing rehabilitation strategies. Active movement therapies show considerable promise but their individual application is still not fully implemented. Among the analysed, available therapeutic modalities, some became widely used in therapeutic practice. Thus, we selected three relatively new methods, i.e. mirror therapy, motor imagery and constraint-induced movement therapy (CIMT). Mirror therapy was initially used in the treatment of phantom pain in patients with amputated limbs and later, in stroke patients. Motor imagery is widely used in sport to improve performance, which raises the possibility of applying it both as a rehabilitative method and in accessing the motor network independently of recovery. Whereas CIMT is based on the paradigm that impairment of arm function is exacerbated by learned non-use and that this, in turn, leads to loss of cortical representation in the upper limb.

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Local GABA concentration is related to network-level resting functional connectivity

eLife ◽

10.7554/elife.01465 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 86

Author(s):

Charlotte J Stagg ◽

Velicia Bachtiar ◽

Ugwechi Amadi ◽

Christel A Gudberg ◽

Andrei S Ilie ◽

...

Keyword(s):

Functional Connectivity ◽

Resting State ◽

Primary Motor Cortex ◽

Empirical Studies ◽

Network Connectivity ◽

Resting State Fmri ◽

Resonance Spectroscopy ◽

Resting State Networks ◽

Inhibitory Neurotransmitter ◽

Motor Network

Anatomically plausible networks of functionally inter-connected regions have been reliably demonstrated at rest, although the neurochemical basis of these ‘resting state networks’ is not well understood. In this study, we combined magnetic resonance spectroscopy (MRS) and resting state fMRI and demonstrated an inverse relationship between levels of the inhibitory neurotransmitter GABA within the primary motor cortex (M1) and the strength of functional connectivity across the resting motor network. This relationship was both neurochemically and anatomically specific. We then went on to show that anodal transcranial direct current stimulation (tDCS), an intervention previously shown to decrease GABA levels within M1, increased resting motor network connectivity. We therefore suggest that network-level functional connectivity within the motor system is related to the degree of inhibition in M1, a major node within the motor network, a finding in line with converging evidence from both simulation and empirical studies.

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