Brain effective connectivity during motor-imagery and execution following stroke and rehabilitation

NeuroImage Clinical, Journal Year: 2015, Volume and Issue: 8, P. 572 - 582

Published: Jan. 1, 2015

Brain areas within the motor system interact directly or indirectly during motor-imagery and motor-execution tasks. These interactions their functionality can change following stroke recovery. How brain network reorganize recover recovery treatment are not well understood. To contribute to answering these questions, we recorded blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals from 10 survivors evaluated dynamical causal modeling (DCM)-based effective connectivity among three areas: primary cortex (M1), pre-motor (PMC) supplementary area (SMA), We compared between affected unaffected hemispheres before after mental practice combined physical therapy as treatments. The (intervention) period varied in length 14 51 days but all patients received same dose of 60 h treatment. Using Bayesian model selection (BMS) approach DCM approach, found that, intervention, dominated tasks modulatory parameters suggested a suppressive influence SM A on M1 task whereas was unrestricted task. that intervention caused reorganization both for hemisphere. averaging (BMA) improved regional PMC stronger M1, There significant behavioral improvement (p = 0.001) sensation movements because reflected by Fugl-Meyer (FMA) measures, which were significantly correlated 0.05) with subset connectivity. findings suggest play crucial role In addition, causes more exchange information than due its interaction A. This study expands our understanding involved two different tasks, commonly used rehabilitation stroke. clear networks leads better helping regain ability.

Language: Английский

---

Optogenetic Mapping after Stroke Reveals Network-Wide Scaling of Functional Connections and Heterogeneous Recovery of the Peri-Infarct

Journal of Neuroscience, Journal Year: 2014, Volume and Issue: 34(49), P. 16455 - 16466

Published: Dec. 3, 2014

We used arbitrary point channelrhodopsin-2 (ChR2) stimulation and wide-scale voltage sensitive dye (VSD) imaging in mice to map altered cortical connectivity at 1 8 weeks after a targeted stroke. Network analysis based on optogenetic revealed symmetrical sham network with distinct sensorimotor association groupings. This symmetry was disrupted stroke: week stroke, we observed widespread depression of optogenetically evoked activity that extended the non-injured hemisphere; by weeks, significant recovery observed. When considered as whole, scaling ChR2-evoked VSD responses from stroke groups match group mean resulted relative distribution indistinguishable group, suggesting network-wide down-scaling connectional diaschisis Closer inspection connections had little peri-infarct, such contralateral visual areas, tended escape damage, whereas some near peri-infarct were more severely affected. within isolated, did not observe equal Peri-infarct sites weak connection strength condition have greatest post-stroke recovery. Our findings suggest that, during recovery, most areas undergo homeostatic upscaling, resulting is similar pre-stroke (sham) network, albeit still depressed. However, zone heterogeneous these points do follow factor expected for entire network.

Language: Английский

---

Neuronal replacement therapy: previous achievements and challenges ahead

npj Regenerative Medicine, Journal Year: 2017, Volume and Issue: 2(1)

Published: Oct. 11, 2017

Lifelong neurogenesis and incorporation of newborn neurons into mature neuronal circuits operates in specialized niches the mammalian brain serves as role model for replacement strategies. However, to which extent can remaining parenchyma, never incorporates new during adulthood, be plastic readily accommodate networks that suffered loss due injury or neurological disease? Which microenvironment is permissive synaptic integration cells perform best? Can lost function restored how adequate participation pre-existing circuitry? Could aberrant connections cause malfunction especially dominated by excitatory neurons, such cerebral cortex? These questions show important connectivity circuitry aspects are regenerative medicine, focus this review. We will discuss impressive advances strategies success from exogenous well endogenous cell sources. Both have seen key novel technologies, like groundbreaking discovery induced pluripotent stem direct reprogramming, offering alternatives transplantation fetal both herald great expectations. For these become reality, analysis now. As our understanding increases, therapy should fulfill those prerequisites network structure function, brain-wide input output. Now time incorporate neural research medicine if we ever want truly repair injury.

Language: Английский

---

Structural connectome disruption at baseline predicts 6-months post-stroke outcome

Human Brain Mapping, Journal Year: 2016, Volume and Issue: 37(7), P. 2587 - 2601

Published: March 26, 2016

In this study, models based on quantitative imaging biomarkers of post-stroke structural connectome disruption were used to predict six-month outcomes in various domains. Demographic information and clinical MRIs collected from 40 ischemic stroke subjects (age: 68.1 ± 13.2 years, 17 female, NIHSS: 6.8 5.6). Diffusion-weighted images create lesion masks, which uploaded the Network Modification (NeMo) Tool. The NeMo Tool, using only MRIs, allows estimation at three levels: whole brain, individual gray matter regions between pairs regions. Partial Least Squares Regression constructed for each level outcomes: applied cognitive, basic mobility daily activity. Models volume created comparison. Cross-validation, bootstrapping multiple comparisons corrections implemented minimize over-fitting Type I errors. regional disconnection model best predicted cognitive (R(2) = 0.56) 0.70), while pairwise activity measure 0.72). These results demonstrate that metrics more accurate than ones increasing anatomical specificity does not always increase accuracy, likely due statistical adjustments concomitant increases data dimensionality. This work establishes Tool's measures baseline disruption, acquired routinely MRI scans, can 6-month functional domains including cognition, motor function activities. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc.

Language: Английский

---

Resolution of High-Frequency Mesoscale Intracortical Maps Using the Genetically Encoded Glutamate Sensor iGluSnFR

Journal of Neuroscience, Journal Year: 2016, Volume and Issue: 36(4), P. 1261 - 1272

Published: Jan. 27, 2016

Wide-field-of-view mesoscopic cortical imaging with genetically encoded sensors enables decoding of regional activity and connectivity in anesthetized behaving mice; however, the kinetics most can be suboptimal for vivo characterization frequency bands higher than 1-3 Hz. Furthermore, existing sensors, particular those that measure calcium (genetically indicators; GECIs), largely monitor suprathreshold activity. Using a sensor extracellular glutamate imaging, we demonstrate rapid virally transduced or transgenically expressed glutamate-sensing fluorescent reporter iGluSnFR. In both awake mice, imaged an 8 × mm field view through intact transparent skull preparation. iGluSnFR revealed representation sensory stimuli were also reflected correlation maps spontaneous activities at frequencies up to alpha band (8-12 Hz). resolved temporal features processing such as intracortical reverberation during visual stimuli. The reporting signals more Emx-GCaMP3 GCaMP6s comparable responses seen RH1692 voltage sensitive dye (VSD), similar signal amplitude. Regional detected by brain identified functional circuits consistent generated from GCaMP3 VSD sensors. Viral transgenic tools have potential utility normal physiology, well neurologic psychiatric pathologies which abnormalities glutamatergic signaling are implicated.We characterized usage perform wide-field-of-view cortex mice. Probes neurotransmitter concentration enable monitoring provide direct is less dependent on nonlinearities associated voltage-gated ion channels. We this has high-frequency signaling. This strategy physiology altered observed. Moreover, comparisons between indicators voltage-sensitive dyes.

Language: Английский

---

Multimodal image registration and connectivity analysis for integration of connectomic data from microscopy to MRI

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: Dec. 3, 2019

Abstract 3D histology, slice-based connectivity atlases, and diffusion MRI are common techniques to map brain wiring. While there many modality-specific tools process these data, is a lack of integration across modalities. We develop an automated resource that combines histologically cleared volumes with atlases MRI, enabling the analysis histological features multiple fiber tracts networks, their correlation in-vivo biomarkers. apply our pipeline in murine stroke model, demonstrating not only strong correspondence between abnormalities CLARITY-tissue staining, but also uncovering acute cellular effects areas connected ischemic core. provide improved maps by quantifying projection terminals from CLARITY viral injections, integrate tracing compare scales. Finally, we demonstrate tract-level changes through this multimodal integration. This can propel investigations network alterations underlying neurological disorders.

Language: Английский

---

Enhancing the alignment of the preclinical and clinical stroke recovery research pipeline: Consensus-based core recommendations from the Stroke Recovery and Rehabilitation Roundtable translational working group

International Journal of Stroke, Journal Year: 2017, Volume and Issue: 12(5), P. 462 - 471

Published: July 1, 2017

Stroke recovery research involves distinct biological and clinical targets compared to the study of acute stroke. Guidelines are proposed for pre-clinical modeling stroke alignment studies trials in recovery.

Language: Английский

---

Rewiring the connectome: Evidence and effects

Neuroscience & Biobehavioral Reviews, Journal Year: 2018, Volume and Issue: 88, P. 51 - 62

Published: March 14, 2018

Neuronal connections form the physical basis for communication in brain. Recently, there has been much interest mapping "connectome" to understand how brain structure gives rise function, and ultimately, behaviour. These attempts map connectome have largely assumed that are stable once formed. Recent studies, however, indicate mammalian brains may undergo rewiring during learning experience-dependent plasticity. This suggests is more dynamic than previously thought. To what extent can neural circuitry be rewired healthy adult brain? The subdivided into multiple levels of scale, from synapses microcircuits through long-range tracts. Here, we examine evidence at each level. We then consider role played by learning. conclude harnessing offers new avenues treat diseases.

Language: Английский

---

Pathoconnectomics of cognitive impairment in small vessel disease: A systematic review

Alzheimer s & Dementia, Journal Year: 2016, Volume and Issue: 12(7), P. 831 - 845

Published: Feb. 25, 2016

Abstract Introduction Cerebral small vessel disease (CSVD) is a highly prevalent condition associated with diffuse ischemic damage and cognitive dysfunction particularly in executive function attention. Functional brain imaging studies can reveal mechanisms of impairment CSVD, although findings are mixed. Methods A systematic review integrating from functional magnetic resonance electroencephalography CSVD involved. Results damages long‐range white matter tracts connecting nodes within distributed networks. It also disrupts frontosubcortical circuits cholinergic fiber mediating attentional processes. These changes, illustrated model network dynamics, synergistically relate to neurodegenerative pathology contributing dementia. Discussion The effects on attention functioning best understood cognition as revealed by neuroimaging. Analysis improve characterization severity treatment effects, it inform theoretical models function.

Language: Английский

---

Enhancing Brain Plasticity to Promote Stroke Recovery

Frontiers in Neurology, Journal Year: 2020, Volume and Issue: 11

Published: Oct. 30, 2020

Stroke disturbs both the structural and functional integrity of brain. The understanding stroke pathophysiology has improved greatly in past several decades. However, effective therapy is still limited, especially for patients who are subacute or chronic phase. Multiple novel therapies have been developed to improve clinical outcomes by improving brain plasticity. These approaches either focus on remodeling restoration constructing a neural bypass avoid injury. This review describes emerging therapies, including modern rehabilitation, stimulation, cell therapy, brain-computer interfaces, peripheral nervous transfer, highlights treatment-induced Key evidence from basic studies underlying mechanisms also briefly discussed. insights should lead deeper overall circuit changes, relevance these changes stroke, treatment progress, which will assist development future enhance function after stroke.

Language: Английский

---