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1.
Methods Mol Biol ; 2861: 89-96, 2025.
Artigo em Inglês | MEDLINE | ID: mdl-39395099

RESUMO

Calcium imaging is a method that was first developed in the mid-1970s yet kept developing until current days to allow accurate measurement of free calcium ions in tissues. This widely used method has provided significant advances to our understanding of cellular signal transduction, including the discovery of subcellular compartmentalization of neurons and astrocytes, the identification of multiple signaling pathways, and mapping the functional connectivity between astrocytes and neuronal networks. Here we describe a method for the loading and imaging of cell-permeable AM ester calcium-sensitive dyes for the in vitro measurement of free intracellular Ca2+ ions in acute brain slices.


Assuntos
Encéfalo , Cálcio , Animais , Cálcio/metabolismo , Cálcio/análise , Encéfalo/metabolismo , Encéfalo/citologia , Camundongos , Astrócitos/metabolismo , Astrócitos/citologia , Neurônios/metabolismo , Neurônios/citologia , Sinalização do Cálcio , Corantes Fluorescentes/química , Imagem Molecular/métodos
2.
Dysphagia ; 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39387924

RESUMO

Swallowing is considered a three-phase mechanism involving the oral, pharyngeal, and esophageal phases. The pharyngeal phase relies on highly coordinated movements in the pharynx and larynx to move food through the aerodigestive crossing. While the brainstem has been identified as the primary control center for the pharyngeal phase of swallowing, existing evidence suggests that the higher brain regions can contribute to controlling the pharyngeal phase of swallowing to match the motor response to the current context and task at hand. This suggests that the pharyngeal phase of swallowing cannot be exclusively reflexive or voluntary but can be regulated by the two neural controlling systems, goal-directed and non-goal-directed. This capability allows the pharyngeal phase of swallowing to adjust appropriately based on cognitive input, learned knowledge, and predictions. This paper reviews existing evidence and accordingly develops a novel perspective to explain these capabilities of the pharyngeal phase of swallowing. This paper aims (1) to integrate and comprehend the neurophysiological mechanisms involved in the pharyngeal phase of swallowing, (2) to explore the reflexive (non-goal-directed) and voluntary (goal-directed) neural systems of controlling the pharyngeal phase of swallowing, (3) to provide a clinical translation regarding the pathologies of these two systems, and (4) to highlight the existing gaps in this area that require attention in future research. This paper, in particular, aims to explore the complex neurophysiology of the pharyngeal phase of swallowing, as its breakdown can lead to serious consequences such as aspiration pneumonia or death.

3.
Curr Biol ; 2024 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-39389059

RESUMO

For the brain to compute object motion in the world during self-motion, it must discount the global patterns of image motion (optic flow) caused by self-motion. Optic flow parsing is a proposed visual mechanism for computing object motion in the world, and studies in both humans and monkeys have demonstrated perceptual biases consistent with the operation of a flow-parsing mechanism. However, the neural basis of flow parsing remains unknown. We demonstrate, at both the individual unit and population levels, that neural activity in macaque middle temporal (MT) area is biased by peripheral optic flow in a manner that can at least partially account for perceptual biases induced by flow parsing. These effects cannot be explained by conventional surround suppression mechanisms or choice-related activity and have substantial neural latency. Together, our findings establish the first neural basis for the computation of scene-relative object motion based on flow parsing.

4.
Exp Brain Res ; 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39368025

RESUMO

Ischemic Conditioning (IC) is a procedure involving brief periods of occlusion followed by reperfusion in stationary limbs. Blood Flow Restriction with Exercise (BFR-E) is a technique comprising blood flow restriction during aerobic or resistance exercise. Both IC and BFR-E are Blood Flow Modulation (BFM) strategies that have shown promise across various health domains and are clinically relevant for stroke rehabilitation. Despite their potential benefits, our knowledge on the application and efficacy of either intervention in stroke is limited. This scoping review aims to synthesize the existing literature on the impact of IC and BFR-E on motor and neurophysiological outcomes in individuals post-stroke. Evidence from five studies displayed enhancements in paretic leg strength, gait speed, and paretic leg fatiguability after IC. Additionally, BFR-E led to improvements in clinical performance, gait parameters, and serum lactate levels. While trends toward motor function improvement were observed post-intervention, statistically significant differences were limited. Neurophysiological changes showed inconclusive results. Our review suggests that IC and BFR-E are promising clinical approaches in stroke, however high-quality studies focusing on neurophysiological mechanisms are required to establish the efficacy and underlying mechanisms of both in stroke. Recommendations regarding future directions and clinical utility are provided.

5.
JDR Clin Trans Res ; : 23800844241277099, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39385370

RESUMO

INTRODUCTION: Xerostomia is a subjective sensation of dry mouth affecting millions of people worldwide. Current management has limitations, often causing side effects. This study aims to investigate whether electrical stimulation of the lingual nerve could offer effective relief for xerostomia sufferers. METHODS: Eligible participants were randomly assigned (1:1) to either the experimental or sham group, receiving electrical stimulation of the lingual nerve (n = 24) or sham stimulation (n = 23) for 12 wk. The primary outcome is the changes in xerostomia score using a 100-mm visual analog scale throughout the therapy. Participants assessed their dryness and assigned corresponding scores, with lower scores indicating more severe dry mouth. Secondary outcomes included remission rate in dry mouth frequency, changes in stimulated/unstimulated salivary flow rate (SSFR/USFR), and changes in Oral Health Impact Profile-14 (OHIP-14) questionnaire scores, where higher scores indicate greater impact on oral quality of life. RESULTS: At week 12, the electrical stimulation group showed greater improvement in xerostomia score compared to the sham group, with a mean between-group difference of 13.8 (95% confidence interval [CI], 10.0-17.6). The therapeutic effect of electrical stimulation was also confirmed by secondary outcomes. The remission rate of dry mouth was higher at 12 wk in the electrical stimulation group (61.9% [95% CI, 40.9%-79.3%] vs. 28.6% [95% CI, 13.8%-50.0%]). Participants in the electrical stimulation group also experienced a greater increase in USFR, with a mean difference of 14.5 (6.1-23.0) µL/min. Moreover, they exhibited significant improvement in OHIP-14 score after 12 wk of therapy, with a mean between-group difference of -10.0 (-13.9 to -6.2). No significant difference was observed between the 2 groups for SSFR (P = 0.702). CONCLUSIONS: Electric stimulation offers promise as a noninvasive, nonpharmacological strategy for the management of xerostomia. Further research is needed to understand its long-term effectiveness, optimal parameters, and underlying mechanisms. KNOWLEDGE TRANSFER STATEMENT: The study confirmed that electrical stimulation of the lingual nerve is a promising noninvasive and nonpharmacological modality for relief of xerostomia.

6.
Mov Disord ; 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39400359

RESUMO

BACKGROUND: Movement clinical neurophysiology studies can distinguish myoclonus, tremor, and other jerky movements; however, there has been limited demonstration of their real-world clinical impact. OBJECTIVE: The aim was to investigate movement study utility in clarifying movement classification and guiding patient management. METHOD: A retrospective study of myoclonus-related movement studies was performed. RESULTS: Of 262 patients referred for consideration of myoclonus, 105 (40%) had myoclonus, 156 (59%) had no myoclonus (the commonest alternative classifications were functional jerks and tremor), and 1 was uncertain. An additional 29 studies identified myoclonus without prior clinical suspicion. A total of 119 of 134 (89%) myoclonus patients had a specific neurophysiologic subtype identified, most commonly cortical (64, 54%). Diagnostic differential narrowed in 60% of patients, and a new diagnosis was made in 42 (14%) patients. Medication changes were made in 151 patients (52%), with improvement in 35 of 51 (67%) with follow-up. CONCLUSIONS: Movement studies effectively determined movement classification and identified unsuspected myoclonus, leading to changes in diagnosis and management. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

7.
Adv Biomed Res ; 13: 60, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39411688

RESUMO

Background: Autonomic function assessment provides valuable information regarding the status of the autonomic nervous system. The time lag between the onset of orthostasis and the peak/nadir of heart rate response is a surrogate of the integrity of underlying autonomic neural pathways. Autonomic response latency (ARL) is a relatively novel yet underreported parameter in this context. Test-retest repeatability of this parameter has not been evaluated previously. Materials and Methods: We recruited 31 healthy adults (17 males and 14 females; 29.00 ± 5.44 years) and subjected them to postural challenge tests on five instances - forenoon and afternoon of day 1, the next day, 1 week later, and 1 month later. Tachycardia and bradycardia latencies (TL and BL) were computed using heart rate derived from digital ECG data. Repeatability was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Results: ICCs for TL and BL were 0.69 (0.56, 0.82) and 0.77 (0.66, 0.87), respectively. The CoVs for TL and BL were 14.8% and 12.4%, respectively. Sex-based subgroup analysis revealed ICCs for TL and BL in males to be 0.71 (0.53, 0.86) and 0.74 (0.57, 0.88) and in females to be 0.68 (0.64, 0.86) and 0.82 (0.66, 0.93), respectively. CoVs for TL and BL were 14.4% and 13.8% in male subjects and 15.4% and 10.7% in female subjects, respectively. Conclusion: ARL to orthostatic challenge demonstrated moderate to good test-retest repeatability. Based on our observations, we propose that ARL has potential as a consistent and repeatable index for the assessment of the integrity of autonomic neural pathways and therefore can help in the diagnosis of autonomic neuropathy.

8.
Epileptic Disord ; 2024 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-39412218

RESUMO

Subclinical rhythmic electrographic discharge of adults (SREDA) is one of the rarest and most challenging non-epileptic electroencephalographic variants. Although the pathogenesis of this activity is unclear, an association with vascular insufficiency and cerebral hypoxia has been proposed. SREDA usually occurs in adulthood, but there are few reports in the pediatric population. We performed a systematic review of the literature, confirming the rarity of this condition in children, and added 5 more subjects. We report on a total of 16 children with SREDA. Sufficient data are available for 15 patients. The mean age at first detection of SREDA was 11.5 years. We observed that 67% (10/15) of the subjects had previous seizures: 80% (8/10) of them had an epilepsy diagnosis and 38% (3/8) had generalized epilepsy. Moreover, 8 of 13 subjects whose medical history was available (61%) had a neurodevelopmental disorder. From an electroencephalographic point of view, we noted a prevalence of bilateral SREDA with atypical localization and abrupt onset and end. Since SREDA can be incorrectly interpreted as an epileptic discharge, with possible therapeutic implications, it is important to consider its possible occurrence also in pediatric patients, perhaps more frequently in those with neurodevelopmental disorders.

9.
Phys Ther ; 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39385459

RESUMO

OBJECTIVE: People who have survived stroke may have motor and cognitive impairments. High dose of motor rehabilitation was found to provide clinically relevant improvement to upper limb (UL) motor function. Besides, mounting evidence suggests that clinical, neural, and neurophysiological features are associated with spontaneous recovery. However, the association between these features and rehabilitation-induced, rather than spontaneous, recovery has never been fully investigated.The objective was to explore the association between rehabilitation dose and UL motor outcome after stroke, as well as to identify which variables can be considered potential candidate predictors of motor recovery. METHODS: People who survived stroke were assessed before and after a period of rehabilitation using motor, cognitive, neuroanatomical, and neurophysiological measures. We investigated the association between dose of rehabilitation and UL response (ie, Fugl-Meyer Assessment for upper extremity [FMA-UE]), using ordinary least squares regression as the primary analysis. To obtain unbiased estimates, adjusting covariates were selected using a directed acyclic graph. RESULTS: Baseline FMA-UE was the only factor associated with motor recovery (b = 0.99; 95% CI = 0.83 to 1.15 points). Attention emerged as a confounder of the association between rehabilitation and final FMA-UE (b = 5.5; 95% CI = -0.8 to 11.9 points), influencing both rehabilitation and UL response. CONCLUSION: Preserved attention in people who have survived stroke might lead to greater UL motor recovery, albeit estimates have high levels of variability. Moreover, the increase in the dose of rehabilitation can lead to 5.5 points improvement on the FMA-UE, a nonsignificant but potentially meaningful finding. The approach described here discloses a new framework for investigating the effect of rehabilitation treatment as a potential driver of recovery. IMPACT: Attentional resources could play a key role in UL motor recovery. There is a potential association between amount of UL recovery and dose of rehabilitation delivered, needing further exploration. Preserved attention and rehabilitation dose are candidate predictors of UL motor recovery.

11.
J Undergrad Neurosci Educ ; 22(3): A160-A166, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39355673

RESUMO

The Sherlock Holmes (SH) Project is a collaborative problem-solving activity in the form of a murder mystery that is a great resource for upper-level undergraduate courses in neurophysiology that emphasize synaptic transmission and neuromuscular communication. This project, originally described by Adler and Schwartz (2006), has become a central focus of the Neurophysiology course at Allegheny College, along with many complementary activities that work to reinforce the neuroscience material and skills such as creative experimental design and analysis. Active Learning research in advanced levels of undergraduate courses is rare in the pedagogy literature, and this paper adds to that body of research. Formal assessment of the course generally and the SH Project specifically support the hypothesis that the active learning pedagogical strategies employed foster a positive and successful learning environment.

12.
BMJ Open ; 14(10): e088000, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39353692

RESUMO

OBJECTIVES: To investigate the association between subelements of physical job demands and cognitive impairment risk in middle-aged and older workers in Korea. DESIGN: Longitudinal study using eight waves (2006-2020) of the Korean Longitudinal Study of Aging. SETTING: Nationally representative sample of the Korean population aged 45 years and older. PARTICIPANTS: 2170 workers aged 45 and older at baseline. PRIMARY OUTCOME MEASURES: Cognitive function was evaluated using the Korean version of the Mini-Mental State Examination and cognitive impairment was defined as a score below 24. RESULTS: High physical strength demands were inversely associated with cognitive impairment (OR 0.31, 95% CI 0.14 to 0.68 for 'always' vs 'never' category). Conversely, frequent heavy lifting (OR 2.67, 95% CI 1.36 to 5.26) and bending, kneeling or squatting (OR 1.69, 95% CI 0.82 to 3.47) tasks were associated with increased impairment risk. Dose-response relationships were observed between all physical job demands and cognitive impairment, persisting among those with lower education but not among those with higher education. CONCLUSIONS: Different types of physical job demands have varying relationships with cognitive impairment in middle-aged and older workers. Tasks requiring high physical strength may protect against cognitive impairment while tasks involving heavy lifting and bending, kneeling or squatting may increase the risk. These findings highlight the need for tailored interventions that consider the type of physical job demands and workers' educational levels to mitigate cognitive impairment risks. Further research is needed to explore the underlying mechanisms and validate these findings.


Assuntos
Disfunção Cognitiva , Humanos , Masculino , Disfunção Cognitiva/epidemiologia , Estudos Longitudinais , República da Coreia/epidemiologia , Pessoa de Meia-Idade , Feminino , Idoso , Remoção , Fatores de Risco , Carga de Trabalho/psicologia , Força Muscular , Envelhecimento/psicologia , Envelhecimento/fisiologia
13.
Brain Sci ; 14(9)2024 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-39335441

RESUMO

BACKGROUND: Musculoskeletal pain is a leading cause of medical visits, posing significant challenges both socially and economically, encouraging the scientific community to continue researching and exploring the most effective methods to address the problem. An alternative way to deal with chronic pain is pain neuroscience education (PNE), a lesson plan that addresses the neurobiology, neurophysiology, and nervous system processing of pain. This method takes the place of the conventional one, which connected pain to tissue damage or nociception. RESULTS: As a result, patients are taught that pain is often not a reliable measure of the health of the tissues but rather the outcome of the nervous system interpreting the injury in conjunction with additional psychosocial variables. In addition to finding research that examine, using neuroimaging, whether the administration of PNE has detectable effects at the level of the central nervous system, this narrative review seeks to clarify what PNE is, how it is administered, and if it is an effective treatment for musculoskeletal pain. CONCLUSIONS: Based on the findings, it appears that PNE is more therapeutically beneficial when combined with therapeutic exercise, when done one-on-one, and during lengthy, frequent sessions. Lastly, even though PNE has no effect on the morphological properties of the gray matter, it appears to cause decreased activation of the regions linked to pain.

14.
Front Comput Neurosci ; 18: 1293279, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39268151

RESUMO

The question of how consciousness and behavior arise from neural activity is fundamental to understanding the brain, and to improving the diagnosis and treatment of neurological and psychiatric disorders. There is significant murine and primate literature on how behavior is related to the electrophysiological activity of the medial prefrontal cortex and its role in working memory processes such as planning and decision-making. Existing experimental designs, specifically the rodent spike train and local field potential recordings during the T-maze alternation task, have insufficient statistical power to unravel the complex processes of the prefrontal cortex. We therefore examined the theoretical limitations of such experiments, providing concrete guidelines for robust and reproducible science. To approach these theoretical limits, we applied dynamic time warping and associated statistical tests to data from neuron spike trains and local field potentials. The goal was to quantify neural network synchronicity and the correlation of neuroelectrophysiology with rat behavior. The results show the statistical limitations of existing data, and the fact that making meaningful comparison between dynamic time warping with traditional Fourier and wavelet analysis is impossible until larger and cleaner datasets are available.

15.
Brain Stimul ; 17(5): 1024-1033, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39218350

RESUMO

BACKGROUND: Awareness is a state of consciousness that enables a subject to interact with the environment. Transient alteration of awareness (AA) is a disabling sign of many types of epileptic seizures. The brain mechanisms of awareness and its alteration are not well known. OBJECTIVE/HYPOTHESIS: Transient and isolated AA induced by electrical brain stimulation during a stereoelectroencephalography (SEEG) recording represents an ideal model for studying the associated modifications of functional connectivity and locating the hubs of awareness networks. METHODS: We investigated the SEEG signals-based brain functional connectivity (FC) changes vs background occurring during AA triggered by three thalamic and two insular stimulations in three patients explored by SEEG in the frame of presurgical evaluation for focal drug-resistant epilepsy. The results were compared to the stimulations of the same sites that did not induce clinical changes (negative stimulations). RESULTS: We observed decreased node strength in the pulvinar, insula, and parietal associative cortices during the thalamic and insular stimulations that induced AA. The link strengths characterizing functional coupling between the thalamus and the insular, prefrontal, temporal, or parietal associative cortices were also decreased. In contrast, there was an increased synchronization between the precuneus and the temporal lateral cortex. These FC changes were absent during the negative stimulations. CONCLUSION: Our study highlights the role of the pulvinar, insular, and parietal hubs in maintaining the awareness networks and paves the way for invasive or non-invasive neuromodulation protocols to reduce AA manifestations during epileptic seizures.

16.
J Physiol ; 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39316518

RESUMO

Excitatory glutamatergic NMDA receptors (NMDARs) are key regulators of spinal pain processing, and yet the biophysical properties of NMDARs in dorsal horn nociceptive neurons remain poorly understood. Despite the clinical implications, it is unknown whether the molecular and functional properties of synaptic NMDAR responses are conserved between males and females or translate from rodents to humans. To address these translational gaps, we systematically compared individual and averaged excitatory synaptic responses from lamina I pain-processing neurons of adult Sprague-Dawley rats and human organ donors, including both sexes. By combining patch-clamp recordings of outward miniature excitatory postsynaptic currents with non-biased data analyses, we uncovered a wide range of decay constants of excitatory synaptic events within individual lamina I neurons. Decay constants of synaptic responses were distributed in a continuum from 1-20 ms to greater than 1000 ms, suggesting that individual lamina I neurons contain AMPA receptor (AMPAR)-only as well as GluN2A-, GluN2B- and GluN2D-NMDAR-dominated synaptic events. This intraneuronal heterogeneity in AMPAR- and NMDAR-mediated decay kinetics was observed across sex and species. However, we discovered an increased relative contribution of GluN2A-dominated NMDAR responses at human lamina I synapses compared with rodent synapses, suggesting a species difference relevant to NMDAR subunit-targeting therapeutic approaches. The conserved heterogeneity in decay rates of excitatory synaptic events within individual lamina I pain-processing neurons may enable synapse-specific forms of plasticity and sensory integration within dorsal horn nociceptive networks. KEY POINTS: Synaptic NMDA receptors (NMDARs) in spinal dorsal horn nociceptive neurons are key regulators of pain processing, but it is unknown whether their functional properties are conserved between males and females or translate from rodents to humans. In this study, we compared individual excitatory synaptic responses from lamina I pain-processing neurons of male and female adult Sprague-Dawley rats and human organ donors. Individual lamina I neurons from male and female rats and humans contain AMPA receptor-only as well as GluN2A, GluN2B- and GluN2D-NMDAR-dominated synaptic events. This may enable synapse-specific forms of plasticity and sensory integration within dorsal horn nociceptive networks. Human lamina I synapses have an increased relative contribution of GluN2A-dominated NMDAR responses compared with rodent synapses. These results uncover a species difference relevant to NMDAR subunit-targeting therapeutic approaches.

17.
Neuroimage Clin ; 44: 103671, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39305652

RESUMO

The consequences of frontotemporal lobar degeneration include changes in prefrontal cortical neurophysiology, with abnormalities of neural dynamics reported in the beta frequency range (14-30 Hz) that correlate with functional severity. We examined beta dynamics in two clinical syndromes associated with frontotemporal lobar degeneration: the behavioral variant of frontotemporal dementia (bvFTD) and progressive supranuclear palsy (PSP). Whilst these two syndromes are partially convergent in cognitive effects, they differ in disease mechanisms such as molecular pathologies and prefrontal atrophy. Whether bvFTD and PSP also differ in neurophysiology remains to be fully investigated. We compared magnetoencephalography from 20 controls, 23 people with bvFTD and 21 people with PSP (Richardson's syndrome) during an auditory roving oddball paradigm. We measured changes in low and high total beta power responses (14-22 and 22-30 Hz respectively) over frontotemporal cortex in the period of the mismatch negativity response (100-250 ms post-stimulus). In controls, we found increased 14-22 Hz beta power following unexpected sensory events (i.e. increased deviant versus standard response), from right prefrontal cortex. Relative to controls, PSP reversed the mismatch response in this time-frequency window, reflecting reduced responses to the deviant stimuli (relative to standard stimuli). Abnormal beta at baseline in PSP could account for the reduced task-modulation of beta. Across bvFTD and PSP groups, the beta response to deviant stimuli (relative to standard stimuli) correlated with clinical severity, but not with atrophy of the prefrontal source region. These findings confirm the proposed importance of higher-order cortical regions, and their beta-power generators, in sensory change detection and context-updating during oddball paradigms. The physiological effects are proposed to result from changes in synaptic density, cortical neurotransmitters and subcortical connections, rather than merely atrophy. Beta-power changes may assist clinical stratification and provide intermediate outcomes for experimental medicine studies of novel therapeutic strategies.

18.
Neuron ; 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39241778

RESUMO

Homeostatic regulation of neuronal activity is essential for robust computation; set-points, such as firing rate, are actively stabilized to compensate for perturbations. The disruption of brain function central to neurodegenerative disease likely arises from impairments of computationally essential set-points. Here, we systematically investigated the effects of tau-mediated neurodegeneration on all known set-points in neuronal activity. We continuously tracked hippocampal neuronal activity across the lifetime of a mouse model of tauopathy. We were unable to detect effects of disease in measures of single-neuron firing activity. By contrast, as tauopathy progressed, there was disruption of network-level neuronal activity, quantified by measuring neuronal pairwise interactions and criticality, a homeostatically controlled, ideal computational regime. Deviations in criticality correlated with symptoms, predicted underlying anatomical pathology, occurred in a sleep-wake-dependent manner, and could be used to reliably classify an animal's genotype. This work illustrates how neurodegeneration may disrupt the computational capacity of neurobiological systems.

20.
medRxiv ; 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39228732

RESUMO

Sports-related concussions (SRCs) pose significant challenges to college-aged athletes, eliciting both immediate symptoms and subacute cognitive and motor function impairment. While most symptoms and impairments resolve within weeks, athletes with repeat SRCs may experience heightened risk for prolonged recovery trajectories, future musculoskeletal injuries, and long-term neurocognitive deficits. This includes impaired dual task performance and altered neurophysiology that could persist across the lifespan and elicit future pathophysiology and neurodegeneration. Thus, it is imperative to improve our understanding of neurophysiology after SRC. This study aimed to investigate the impact of repeat SRCs on dual task performance and associated neural recruitment using functional near-infrared spectroscopy (fNIRS). A total of 37 college-aged athletes (ages 18-24) participated in this cross-sectional observational study. Among these athletes, 20 had a history of two or more SRCs, while 17 had never sustained a SRC and served as controls. Participants completed the Neuroimaging-Compatible Dual Task Screen (NC-DTS) while fNIRS measured neural recruitment in the frontoparietal attention network and the primary motor and sensory cortices. Behavioral analysis revealed that athletes with repeat SRCs exhibited comparable single task and dual task performance to control athletes. Additionally, dual task effects (DTE), which capture performance declines in dual tasks versus single tasks, did not significantly differ between groups. Notably, the cohort of athletes with repeat SRC in this study had a longer time since their last SRC (mean = 1.75 years) than majority of previous SRC studies. Neuroimaging results indicated altered neural recruitment patterns in athletes with multiple repeat SRCs during both single and dual tasks. Specifically, athletes with repeat SRCs demonstrated increased prefrontal cortex (PFC) activation during single motor tasks compared to controls (P < 0.001, d = 0.47). Conversely, during dual tasks, these same athletes exhibited reduced PFC activation (P < 0.001, d = 0.29) and primary motor cortex (M1) activation (P = 0.038, d = 0.16) compared to their single task activation. These findings emphasize the complex relationship between SRC history, dual task performance, and changes in neurophysiology. While athletes with repeat SRCs demonstrate recovery in behavioral dual task performance, persistent alterations in neural recruitment patterns suggest ongoing neurophysiological changes, possibly indicating compensatory neural strategies and inefficient neural resource allocation, even beyond symptom resolution and medical clearance. Understanding the compensatory neural recruitment strategies that support behavioral performance following repeat SRCs can inform return-to-play decisions, future musculoskeletal injury risk, and the long-term impact of SRCs on neurocognitive function.

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