Disentangling neuroplasticity mechanisms in post-stroke language recovery

Brain and Language, Journal Year: 2024, Volume and Issue: 251, P. 105381 - 105381

Published: Feb. 24, 2024

A major objective in post-stroke aphasia research is to gain a deeper understanding of neuroplastic mechanisms that drive language recovery, with the ultimate goal enhancing treatment outcomes. Subsequent recent advances neuroimaging techniques, we now have ability examine more closely how neural activity patterns change after stroke. However, way these changes relate impairments and recovery still debated. The aim this review provide theoretical framework better investigate interpret neuroplasticity underlying aphasia. We detail two sets observed at synaptic level may explain functional findings network level: feedback-based homeostatic plasticity associative Hebbian plasticity. In conjunction mechanisms, higher-order cognitive control processes dynamically modulate other regions meet communication demands, despite reduced resources. This work provides network-level neurobiological for can be used define guidelines personalized development.

Language: Английский

---

Pain without presence: a narrative review of the pathophysiological landscape of phantom limb pain

Frontiers in Pain Research, Journal Year: 2025, Volume and Issue: 6

Published: Feb. 18, 2025

Phantom limb pain (PLP) is defined as the perception of in a that has been amputated. In United States, approximately 30,000-40,000 amputations are performed annually with an estimated 2.3 million people living amputations. The prevalence PLP among amputees 64%. Over years, various theories regarding etiology have proposed, some gaining more prominence than others. Yet, there lack consensus on mechanisms current literature exploring pathophysiology multifactorial, involving complex interactions between central and peripheral nervous systems, psychosocial factors, genetic influences. This review seeks to enhance understanding by its multifaceted pathophysiology, including predispositions. We highlight historical aspects PLP, examining how these expanded include dimensions associated chronic amputees. Additionally, we present significant findings from both human animal studies focused neuroaxial systems recent advances molecular research further elucidate multifactorial nature PLP. Ultimately, hope integration theoretical frameworks will lay robust foundation for future

Language: Английский

---

Motor somatotopy impacts imagery strategy success in human intracortical brain-computer interfaces

Journal of Neural Engineering, Journal Year: 2025, Volume and Issue: 22(2), P. 026004 - 026004

Published: Feb. 24, 2025

Objective:The notion of a somatotopically organized motor cortex, with movements different body parts being controlled by spatially distinct areas is well known. However, recent studies have challenged this and suggested more distributed representation movement control. This shift in perspective has significant implications, particularly when considering the implantation location electrode arrays for intracortical brain-computer interfaces (iBCIs). We sought to evaluate whether neural recordings from precentral gyrus, thus underlying somatotopy, any impact on imagery strategies that can enable successful iBCI control.Approach:Three individuals spinal cord injury were enrolled an ongoing clinical trial iBCI. Participants had two microelectrode implanted arm and/or hand gyrus based presurgical functional imaging. Neural data recorded while participants attempted perform hand, wrist, elbow, shoulder.Main results:We found located medially significantly activity during proximal (elbow, shoulder) than did lateral arrays, which captured related distal (hand, wrist). also evaluated relative contribution each participant decoding accuracy calibration decoder translation grasping tasks. For both task types, strategy (e.g. reaching vs wrist movements) contributions array decoding. Overall, we some evidence broad tuning movements; however, there was clear bias amount information accessible about type cortex.Significance:These results demonstrate classical concepts somatotopy real consequences use, highlight importance planning implantation.

Language: Английский

---

Longitudinal stability of individual brain plasticity patterns in blindness

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(32)

Published: July 30, 2024

The primary visual cortex (V1) in blindness is engaged a wide spectrum of tasks and sensory modalities, including audition, touch, language, memory. This widespread involvement raises questions regarding the constancy its role whether it might exhibit flexibility function over time, connecting to diverse network functions specific task demands. would suggest that reorganized V1 assumes like multiple-demand system regions. Alternatively, varying patterns plasticity blind may be attributed individual factors, with different individuals recruiting preferentially for functions. In support this, we recently showed functional connectivity (FC) varies greatly across individuals. But do these represent stable plasticity, or are they driven more by instantaneous changes, now inhabiting V1? Here, tested FC from time. We show two years, unique highly small sample repeatedly sampled congenitally Further, using multivoxel pattern analysis, demonstrate reorganization allow decoding participant identity. Together recent evidence substantial differences connectivity, this indicates there consistent blindness, which differ each individual. suggests variability could used seek neuromarkers sight rehabilitation assistive approaches.

Language: Английский

---

Remapping and Reconnecting the Language Network after Stroke

Brain Sciences, Journal Year: 2024, Volume and Issue: 14(5), P. 419 - 419

Published: April 24, 2024

Here, we review the literature on neurotypical individuals and with post-stroke aphasia showing that right-hemisphere regions homologous to language network other regions, like right cerebellum, are activated in tasks support even healthy people. We propose recovery occurs largely by potentiating hemisphere networks previously supported a lesser degree modulating connection strength between nodes of undamaged left-hemisphere network. Based this premise (supported evidence review), interventions should be aimed at through Hebbian learning or augmenting connections neuroplasticity, such as non-invasive brain stimulation perhaps modulation neurotransmitters involved neuroplasticity. treatment studies have taken approach. conclude further rehabilitation aim is justified.

Language: Английский

---

A roadmap for implanting microelectrode arrays to evoke tactile sensations through intracortical microstimulation

medRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: April 28, 2024

Abstract Intracortical microstimulation (ICMS) is a method for restoring sensation to people with paralysis as part of bidirectional brain-computer interface restore upper limb function. Evoking tactile sensations the hand through ICMS requires precise targeting implanted electrodes. Here we describe presurgical imaging procedures used generate functional maps area somatosensory cortex and subsequent planning that guided implantation intracortical microelectrode arrays. In five participants cervical spinal cord injury, across two study locations, this procedure successfully enabled ICMS-evoked localized at least first four digits hand. The developed clinical trial provide roadmap other studies ensure successful placement stimulation

Language: Английский

---

Evoking stable and precise tactile sensations via multi-electrode intracortical microstimulation of the somatosensory cortex

Nature Biomedical Engineering, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 6, 2024

Tactile feedback from brain-controlled bionic hands can be partially restored via intracortical microstimulation (ICMS) of the primary somatosensory cortex. In ICMS, location percepts depends on electrode's and percept intensity stimulation frequency amplitude. Sensors a hand thus linked to somatotopically appropriate electrodes, contact force each sensor used determine amplitude stimulus. Here we report systematic investigation localization ICMS-evoked in three participants with cervical spinal cord injury. A retrospective analysis projected fields showed that they were typically composed focal hotspot diffuse borders, arrayed keeping their underlying receptive stable throughout duration study. When testing participants' ability rapidly localize single ICMS presentation, individual electrodes evoked only weak sensations, making object discrimination difficult. However, overlapping multiple produced more localizable intense sensations allowed for precise use hand. An injury shows produce are easily localizable.

Language: Английский

---

Developing cortex is functionally pluripotent: Evidence from blindness

Developmental Cognitive Neuroscience, Journal Year: 2024, Volume and Issue: 66, P. 101360 - 101360

Published: Feb. 21, 2024

How rigidly does innate architecture constrain function of developing cortex? What is the contribution early experience? We review insights into these questions from visual cortex in people born blind. In blindness, occipital cortices are active during auditory and tactile tasks. 'cross-modal' plasticity tells us about cortical flexibility debated. On one hand, networks blind respond to higher cognitive information, such as sentence grammar, suggesting drastic repurposing. other, line with 'metamodal' accounts, sighted populations show shared domain preferences ventral occipito-temporal (vOTC), areas switch input modality but perform same or similar perceptual functions (e.g., face recognition) blindness. Here we bring disparate literatures together, reviewing synthesizing evidence that speaks whether have different people. Together, suggests incorporated higher-cognitive fronto-parietal) networks, which a major source long-range system. propose connectivity-constrained experience-dependent account. Functional development constrained by anatomical connectivity, experience behavioral needs. Infant pluripotent, constraints develop functional outcomes.

Language: Английский

---

Adaptation in the spinal cord after stroke: Implications for restoring cortical control over the final common pathway

The Journal of Physiology, Journal Year: 2024, Volume and Issue: 603(3), P. 685 - 721

Published: May 24, 2024

Control of voluntary movement is predicated on integration between circuits in the brain and spinal cord. Although damage often restricted to supraspinal or cases neurological injury, both motor neurons axons linking these cells cortical origins descending commands begin showing changes soon after injured by stroke. The concept 'transneuronal degeneration' not new has been documented histological, imaging electrophysiological studies dating back over a century. Taken together, evidence from comports more with system attempting survive rather than one passively surrendering degeneration. There tends be at least some preservation fibres brainstem origin along course white matter tracts, even severe cases. Myelin-associated proteins are observed cord years stroke onset. Spinal remain morphometrically unaltered. Skeletal muscle once innervated that lose their source trophic input receive collaterals adjacent neurons, causing units consolidate increase size. level excitability within distributed network mediating needed facilitate recovery, minimal structural connectivity can support meaningful distal limb function. Restoring access final common pathway via remains therefore represents viable target for directed plasticity, particularly light recent advances rehabilitation medicine.

Language: Английский

---

Changes in primary visual and auditory cortex of blind and sighted adults following 10 weeks of click-based echolocation training

Cerebral Cortex, Journal Year: 2024, Volume and Issue: 34(6)

Published: May 25, 2024

Recent work suggests that the adult human brain is very adaptable when it comes to sensory processing. In this context, has also been suggested structural "blueprints" may fundamentally constrain neuroplastic change, e.g. in response deprivation. Here, we trained 12 blind participants and 14 sighted echolocation over a 10-week period, used MRI pre-post design measure functional changes. We found together showed training-induced increase activation left right V1 echoes, finding difficult reconcile with view cortex strictly organized by modality. Further, training induced A1 sounds per se (i.e. not echo-specific), was accompanied an gray matter density adjacent acoustic areas participants. The similarity results between consistent idea reorganization be governed similar principles two groups, yet our analyses differences groups suggesting more nuanced required.

Language: Английский

---