Global neurotrauma research challenges and opportunities. Nature. 2015;527:S193-S197. [PMID: 26580327 DOI: 10.1038/nature16035]

Preso enhances mGluR1-mediated excitotoxicity by modulating the phosphorylation of mGluR1-Homer1 complex and facilitating an ER stress after traumatic brain injury

Glutamate receptor (GluR)-mediated excitotoxicity is an important mechanism causing delayed neuronal injury after traumatic brain injury (TBI). Preso, as a core scaffolding protein of postsynaptic density (PSD), is considered an important regulator during excitotoxicity and TBI and combines with glutamate receptors to form functional units for excitatory glutamatergic neurotransmission, and elucidating the mechanisms of these functional units will provide new targets for the treatment of TBI. As a multidomain scaffolding protein, Preso directly interacts with metabotropic GluR (mGluR) and another scaffold protein, Homer. Because the mGluR-Homer complex plays a crucial role in TBI, modulation of this complex by Preso may be an important mechanism affecting the excitotoxic damage to neurons after TBI. Here, we demonstrate that Preso facilitates the interaction between metabotropic mGluR1 and Homer1 to activate mGluR1 signaling and cause excitotoxic neuronal injury and endoplasmic reticulum (ER) stress after TBI. The regulatory effect of Preso on the mGluR1-Homer1 complex is dependent on the direct association between Preso and this complex and also involves the phosphorylation of the interactive binding sites of mGluR1 and Homer1 by Preso. Further studies confirmed that Preso, as an adaptor of cyclin-dependent kinase 5 (CDK5), promotes the phosphorylation of the Homer1-binding site on mGluR1 by CDK5 and thereby enhances the interaction between mGluR1 and Homer1. Preso can also promote the formation of the mGluR1-Homer1 complex by inhibiting the phosphorylation of the Homer1 hinge region by Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα). Based on these molecular mechanisms, we designed several blocking peptides targeting the interaction between Preso and the mGluR1-Homer1 complex and found that directly disrupting the association between mGluR1 and scaffolding proteins significantly promotes the recovery of motor function after TBI.

Lost Self to Present Self: A Case Report of Narrative Therapy for a Woman with Acquired Brain Injury

BACKGROUND

Psychotherapy for people with acquired brain injury (ABI) is considered to be an important component of a holistic neuropsychological rehabilitation approach. This helps in making sense of the loss of the sense of self they experience. Gender, premorbid personality, and socio-cultural discourses guide this process of understanding. Narrative formulation takes these considerations into account and, thus, can be used for formulating therapeutic plans.

AIM

To present a case report which highlights the use of narrative case formulation to understand the psychological, social, and cultural factors forming the dominant discourse of a woman with ABI.

METHODS

Ms. VA, a 43-year-old female, presented herself with a diagnosis of hypoxic ischemic encephalopathy with small chronic infarcts with gliosis in the bilateral cerebellar hemisphere, myoclonic seizures, mild cognitive impairment, depression, generalized dystonia, and bronchial asthma. Along with neuropsychological rehabilitation and cognitive retraining, 25 sessions of psychotherapy using narrative formulation were performed.

RESULTS

Following the therapy, microgains such as a developing strong therapeutic relationship, accommodating vulnerability in her narrative, and finding moments of independence and assertion within the constraints of ABI were observed. Acceptance of her current predicament vis-à-vis her lost self and finding meaning in her new self were facilitated.

CONCLUSION

There is paucity of research detailing psychotherapeutic management of ABI, especially in India. Psychotherapy, particularly using narrative formulation, can be helpful in understanding the intersections of gender role and expectations, premorbid personality and ABI, and aiding the post-ABI rehabilitation and adjustment. Future work in this area can explore the socio-cultural aspects that play an important role in the therapy process.

IMproving psYchosocial adjustment to Traumatic Brain Injury from acute to chronic injury through development and evaluation of the myTBI online psychoeducation platform: protocol for a mixed-methods study

INTRODUCTION

This protocol describes the myTBI study which aims to: (1) develop an online psychoeducation platform for people with traumatic brain injury (TBI), their family members/caregivers, and healthcare staff to improve psychosocial adjustment to TBI across different phases of injury (acute, postacute, and chronic), and (2) undertake an evaluation of efficacy, acceptability, and feasibility.

METHODS AND ANALYSIS

A three-stage mixed-methods research design will be used. The study will be undertaken across four postacute community-based neurorehabilitation and disability support services in Western Australia. Stage 1 (interviews and surveys) will use consumer-driven qualitative methodology to: (1) understand the recovery experiences and psychosocial challenges of people with TBI over key stages (acute, postacute, and chronic), and (2) identify required areas of psychosocial support to inform the psychoeducation platform development. Stage 2 (development) will use a Delphi expert consensus method to: (1) determine the final psychoeducation modules, and (2) perform acceptance testing of the myTBI platform. Finally, stage 3 (evaluation) will be a randomised stepped-wedge trial to evaluate efficacy, acceptability, and feasibility. Outcomes will be measured at baseline, postintervention, follow-up, and at final discharge from services. Change in outcomes will be analysed using multilevel mixed-effects modelling. Follow-up surveys will be conducted to evaluate acceptability and feasibility.

ETHICS AND DISSEMINATION

Ethics approval was granted by North Metropolitan Health Service Mental Health Research Ethics and Governance Office (RGS0000005877). Study findings will be relevant to clinicians, researchers, and organisations who are seeking a cost-effective solution to deliver ongoing psychoeducation and support to individuals with TBI across the recovery journey.

TRIAL REGISTRATION NUMBER

ACTRN12623000990628.

Non-stem cell-derived exosomes: a novel therapeutics for neurotrauma

Neurotrauma, encompassing traumatic brain injuries (TBI) and spinal cord injuries (SCI) impacts a significant portion of the global population. While spontaneous recovery post-TBI or SCI is possible, recent advancements in cell-based therapies aim to bolster these natural reparative mechanisms. Emerging research indicates that the beneficial outcomes of such therapies might be largely mediated by exosomes secreted from the administered cells. While stem cells have garnered much attention, exosomes derived from non-stem cells, including neurons, Schwann cells, microglia, and vascular endothelial cells, have shown notable therapeutic potential. These exosomes contribute to angiogenesis, neurogenesis, and axon remodeling, and display anti-inflammatory properties, marking them as promising agents for neurorestorative treatments. This review provides an in-depth exploration of the current methodologies, challenges, and future directions regarding the therapeutic role of non-stem cell-derived exosomes in neurotrauma.

Cognitive and Motor Function Effects of Antipsychotics in Traumatic Brain Injury: A Systematic Review of Pre-Clinical Studies

Traumatic brain injury (TBI) survivors often suffer from agitated behaviors and will most likely receive pharmacological treatments. Choosing an optimal and safe treatment that will not interfere with neurological recovery remains controversial. By interfering with dopaminergic circuits, antipsychotics may impede processes important to cognitive recovery. Despite their frequent use, there have been no large randomized controlled studies of antipsychotics for the management of agitated behaviors during the acute TBI recovery period. We conducted a systematic review and meta-analysis of pre-clinical studies evaluating the effects of antipsychotics post-TBI on both cognitive and motor recovery. MEDLINE and Embase databases were searched up to August 2, 2023. Pre-clinical studies evaluating the effects of antipsychotics on cognitive and motor functions post-TBI were considered. Risk of bias was evaluated with the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. We identified 15 studies including a total of 1188 rodents, mostly conducted in male Sprague-Dawley rats using cortical impact injury. The analysis revealed no consistent effect of haloperidol on motor functions, but risperidone was associated with a significant impairment in motor function on day 5 post-injury (7.05 sec; 95% confidence interval [CI]: 1.47, 12.62; I2 = 92%). Other atypical antipsychotics did not result in impaired motor function. When evaluating cognitive function, haloperidol- (23.00 sec; 95% CI: 17.42-28.59; I2 = 7%) and risperidone-treated rats (24.27 sec; 95% CI: 16.18-32.36; I2 = 0%) were consistently impaired when compared to controls. In studies evaluating atypical antipsychotics, no impairments were observed. Clinicians should avoid the regular use of haloperidol and risperidone, and future human studies should be conducted with atypical antipsychotics.

Reactive gliosis in traumatic brain injury: a comprehensive review

Traumatic brain injury (TBI) is one of the most common pathological conditions impacting the central nervous system (CNS). A neurological deficit associated with TBI results from a complex of pathogenetic mechanisms including glutamate excitotoxicity, inflammation, demyelination, programmed cell death, or the development of edema. The critical components contributing to CNS response, damage control, and regeneration after TBI are glial cells-in reaction to tissue damage, their activation, hypertrophy, and proliferation occur, followed by the formation of a glial scar. The glial scar creates a barrier in damaged tissue and helps protect the CNS in the acute phase post-injury. However, this process prevents complete tissue recovery in the late/chronic phase by producing permanent scarring, which significantly impacts brain function. Various glial cell types participate in the scar formation, but this process is mostly attributed to reactive astrocytes and microglia, which play important roles in several brain pathologies. Novel technologies including whole-genome transcriptomic and epigenomic analyses, and unbiased proteomics, show that both astrocytes and microglia represent groups of heterogenic cell subpopulations with different genomic and functional characteristics, that are responsible for their role in neurodegeneration, neuroprotection and regeneration. Depending on the representation of distinct glia subpopulations, the tissue damage as well as the regenerative processes or delayed neurodegeneration after TBI may thus differ in nearby or remote areas or in different brain structures. This review summarizes TBI as a complex process, where the resultant effect is severity-, region- and time-dependent and determined by the model of the CNS injury and the distance of the explored area from the lesion site. Here, we also discuss findings concerning intercellular signaling, long-term impacts of TBI and the possibilities of novel therapeutical approaches. We believe that a comprehensive study with an emphasis on glial cells, involved in tissue post-injury processes, may be helpful for further research of TBI and be the decisive factor when choosing a TBI model.

Effect of continuous hypertonic saline infusion on clinical outcomes in patients with traumatic brain injury

Osmotic therapy has been recognized as an important treatment option for patients with traumatic brain injury (TBI). Nevertheless, the effect of hypertonic saline (HTS) remains unknown, as findings are primarily based on a large database. This study aimed to elucidate the effect of HTS on the clinical outcomes of patients with TBI admitted to the intensive care unit (ICU). We retrospectively identified patients with moderate-to-severe TBI from two public databases: Medical Information Mart for Intensive Care (MIMIC)-IV and eICU Collaborative Research Database (eICU-CRD). A marginal structural Cox model (MSCM) was used, with time-dependent variates designed to reflect exposure over time during ICU stay. Trajectory modeling based on the intracranial pressure evolution pattern allowed for the identification of subgroups. Overall, 130 (6.65%) of 1955 eligible patients underwent HTS. MSCM indicated that the HTS significantly associated with higher infection complications (e.g., urinary tract infection (HR 1.88, 95% CI 1.26-2.81, p = 0.002)) and increased ICU LOS (HR 2.02, 95% CI 1.71-2.40, p < 0.001). A protective effect of HTS on GCS was found in subgroups with medium and low intracranial pressure. Our study revealed no significant difference in mortality between patients who underwent HTS and those who did not. Increased occurrence rates of infection and electrolyte imbalance are inevitable outcomes of continuous HTS infusion. Although the study suggests slight beneficial effects, including better neurological outcomes, these results warrant further validation.

Consensus-Based Development of a Global Registry for Traumatic Brain Injury: Establishment, Protocol, and Implementation

BACKGROUND AND OBJECTIVES

Global disparity exists in the demographics, pathology, management, and outcomes of surgically treated traumatic brain injury (TBI). However, the factors underlying these differences, including intervention effectiveness, remain unclear. Establishing a more accurate global picture of the burden of TBI represents a challenging task requiring systematic and ongoing data collection of patients with TBI across all management modalities. The objective of this study was to establish a global registry that would enable local service benchmarking against a global standard, identification of unmet need in TBI management, and its evidence-based prioritization in policymaking.

METHODS

The registry was developed in an iterative consensus-based manner by a panel of neurotrauma professionals. Proposed registry objectives, structure, and data points were established in 2 international multidisciplinary neurotrauma meetings, after which a survey consisting of the same data points was circulated within the global neurotrauma community. The survey results were disseminated in a final meeting to reach a consensus on the most pertinent registry variables.

RESULTS

A total of 156 professionals from 53 countries, including both high-income countries and low- and middle-income countries, responded to the survey. The final consensus-based registry includes patients with TBI who required neurosurgical admission, a neurosurgical procedure, or a critical care admission. The data set comprised clinically pertinent information on demographics, injury characteristics, imaging, treatments, and short-term outcomes. Based on the consensus, the Global Epidemiology and Outcomes following Traumatic Brain Injury (GEO-TBI) registry was established.

CONCLUSION

The GEO-TBI registry will enable high-quality data collection, clinical auditing, and research activity, and it is supported by the World Federation of Neurosurgical Societies and the National Institute of Health Research Global Health Program. The GEO-TBI registry ( https://geotbi.org ) is now open for participant site recruitment. Any center involved in TBI management is welcome to join the collaboration to access the registry.

Physicians' beliefs and perceived importance of traumatic brain injury-associated agitation in critically ill patients: a survey of Canadian intensivists

PURPOSE

Agitation is a common behavioural problem following traumatic brain injury (TBI). Intensive care unit (ICU) physicians' perspectives regarding TBI-associated agitation are unknown. Our objective was to describe physicians' beliefs and perceived importance of TBI-associated agitation in critically ill patients.

METHODS

Following current standard guidance, we built an electronic, self-administrated, 42-item survey, pretested it for reliability and validity, and distributed it to 219 physicians working in 18 ICU level-1 trauma centres in Canada. We report the results using descriptive statistics.

RESULTS

The overall response rate was 93/219 (42%), and 76/93 (82%) respondents completed the full survey. Most respondents were men with ten or more years of experience. Respondents believed that pre-existing dementia (90%) and regular recreational drug use (86%) are risk factors for agitation. Concerning management, 91% believed that the use of physical restraints could worsen agitation, 90% believed that having family at the bedside reduces agitation, and 72% believed that alpha-2 adrenergic agonists are efficacious for managing TBI agitation. Variability was observed in beliefs on epidemiology, sex, gender, age, socioeconomic status, and other pharmacologic options. Respondents considered TBI agitation frequent enough to justify the implementation of management protocols (87%), perceived the current level of clinical evidence on TBI agitation management to be insufficient (84%), and expressed concerns about acute and long-term detrimental outcomes and burden to patients, health care professionals, and relatives (85%).

CONCLUSION

Traumatic brain injury-associated agitation in critically ill patients was perceived as an important issue for most ICU physicians. Physicians agreed on multiple approaches to manage TBI-associated agitation although agreement on epidemiology and risk factors was variable.

Traumatic brain injury disrupts state-dependent functional cortical connectivity in a mouse model

Traumatic brain injury (TBI) is the leading cause of death in young people and can cause cognitive and motor dysfunction and disruptions in functional connectivity between brain regions. In human TBI patients and rodent models of TBI, functional connectivity is decreased after injury. Recovery of connectivity after TBI is associated with improved cognition and memory, suggesting an important link between connectivity and functional outcome. We examined widespread alterations in functional connectivity following TBI using simultaneous widefield mesoscale GCaMP7c calcium imaging and electrocorticography (ECoG) in mice injured using the controlled cortical impact (CCI) model of TBI. Combining CCI with widefield cortical imaging provides us with unprecedented access to characterize network connectivity changes throughout the entire injured cortex over time. Our data demonstrate that CCI profoundly disrupts functional connectivity immediately after injury, followed by partial recovery over 3 weeks. Examining discrete periods of locomotion and stillness reveals that CCI alters functional connectivity and reduces theta power only during periods of behavioral stillness. Together, these findings demonstrate that TBI causes dynamic, behavioral state-dependent changes in functional connectivity and ECoG activity across the cortex.

Methylphenidate Ameliorates Behavioural and Neurobiological Deficits in Executive Function for Patients with Chronic Traumatic Brain Injury

(1) Background: Traumatic brain injury (TBI) often results in cognitive impairments, including in visuospatial planning and executive function. Methylphenidate (MPh) demonstrates potential improvements in several cognitive domains in patients with TBI. The Tower of London (TOL) is a visuospatial planning task used to assess executive function. (2) Methods: Volunteers with a history of TBI (n = 16) participated in a randomised, double-blinded, placebo-controlled, fMRI study to investigate the neurobiological correlates of visuospatial planning and executive function, on and off MPh. (3) Results: Healthy controls (HCs) (n = 18) and patients on placebo (TBI-placebo) differed significantly in reaction time (p < 0.0005) and accuracy (p < 0.0001) when considering all task loads, but especially for high cognitive loads for reaction time (p < 0.001) and accuracy (p < 0.005). Across all task loads, TBI-MPh were more accurate than TBI-placebo (p < 0.05) but remained less accurate than HCs (p < 0.005). TBI-placebo substantially improved in accuracy with MPh administration (TBI-MPh) to a level statistically comparable to HCs at low (p = 0.443) and high (p = 0.175) cognitive loads. Further, individual patients that performed slower on placebo at low cognitive loads were faster with MPh (p < 0.05), while individual patients that performed less accurately on placebo were more accurate with MPh at both high and low cognitive loads (p < 0.005). TBI-placebo showed reduced activity in the bilateral inferior frontal gyri (IFG) and insulae versus HCs. MPh normalised these regional differences. MPh enhanced within-network connectivity (between parietal, striatal, insula, and cerebellar regions) and enhanced beyond-network connectivity (between parietal, thalamic, and cerebellar regions). Finally, individual changes in cerebellar-thalamic (p < 0.005) and cerebellar-parietal (p < 0.05) connectivity with MPh related to individual changes in accuracy with MPh. (4) Conclusions: This work highlights behavioural and neurofunctional differences between HCs and patients with chronic TBI, and that adverse differences may benefit from MPh treatment.

Trends and hotspots in research of traumatic brain injury from 2000 to 2022: A bibliometric study

Traumatic brain injury (TBI) is a major health concern globally, which is characterized by high morbidity and mortality rates. Since the 21st century, TBI has received increasing attention and the number of publications is growing rapidly. This study aimed to characterize the volume and quality of scholarly output on TBI and identify the most impactful literature, research trends, and hotspots from the year 2000-2022. We searched publications on TBI through the Web of Science Core Collection-Science Citation Index Expanded database which were published from 2000 to 2022. Basic information of each paper, including publication year, countries, authors, affiliations, journal, fundings, subject areas, and keywords were collected for further analysis by using Microsoft Excel, VOSviewer, and CiteSpace software. A total of 47231 TBI-related publications were identified through database retrieval. The annual number of publications on TBI has increased steadily over the past twenty years and the number in the year 2022 is sevenfold higher than that in 2000. The United States of America (USA) was the leading country in both numbers of publications and citations, which is consistent with the finding that it had the most funding agencies. Menon DK was the author with the highest influence and the University of California System was the most productive affiliation. Moreover, keywords analysis suggested that the research topics can be mainly divided into six categories: management, rehabilitation, mechanisms, concussion, neuroimaging, and neuroendocrine. This study visualized the trends and focuses of scientific research related to TBI, both quantitatively and qualitatively. The USA had a relatively high academic impact owing to its productive experts and institutions in this field. Neuroinflammation, machine learning, tranexamic acid, and extracellular vesicles are currently hot topics in the field of TBI.

Therapeutic Effects of Melatonin in the Regulation of Ferroptosis: A Review of Current Evidence

Ferroptosis is implicated in the pathogenesis of multiple diseases, including neurodegenerative diseases, cardiovascular diseases, kidney pathologies, ischemia-reperfusion injury, and cancer. The current review article highlights the involvement of ferroptosis in traumatic brain injury, acute kidney damage, ethanol-induced liver injury, and PM2.5-induced lung injury. Melatonin, a molecule produced by the pineal gland and many other organs, is well known for its anti- aging, anti-inflammatory, and anticancer properties and is used in the treatment of different diseases. Melatonin's ability to activate anti-ferroptosis pathways including sirtuin (SIRT)6/p- nuclear factor erythroid 2-related factor 2 (Nrf2), Nrf2/ antioxidant responsive element (ARE)/ heme oxygenase (HO-1)/SLC7A11/glutathione peroxidase (GPX4)/ prostaglandin-endoperoxide synthase 2 (PTGS2), extracellular signal-regulated kinase (ERK)/Nrf2, ferroportin (FPN), Hippo/ Yes-associated protein (YAP), Phosphoinositide 3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) and SIRT6/ nuclear receptor coactivator 4 (NCOA4)/ ferritin heavy chain 1 (FTH1) signaling pathways suggests that it could serve as a valuable therapeutic agent for preventing cell death associated with ferroptosis in various diseases. Further research is needed to fully understand the precise mechanisms by which melatonin regulates ferroptosis and its potential as a therapeutic target.

Identification and Validation of Synapse-related Hub Genes after Spinal Cord Injury by Bioinformatics Analysis

BACKGROUND

Spinal cord injury (SCI) is a neurological disease with high morbidity and mortality. Previous studies have shown that abnormally expressed synapse-related genes are closely related to the occurrence and development of SCI. However, little is known about the interaction of these aberrantly expressed genes and the molecular mechanisms that play a role in the injury response. Therefore, deeply exploring the correlation between synapse-related genes and functional recovery after spinal cord injury and the molecular regulation mechanism is of great significance.

METHODS

First, we selected the function GSE45006 dataset to construct three clinically meaningful gene modules by hierarchical clustering analysis in 4 normal samples and 20 SCI samples. Subsequently, we performed functional and pathway enrichment analyses of key modules.

RESULTS

The results showed that related module genes were significantly enriched in synaptic structures and functions, such as the regulation of synaptic membranes and membrane potential. A protein-protein interaction network (PPI) was constructed to identify 10 hub genes of SCI, and the results showed that Snap25, Cplx1, Stxbp1, Syt1, Rims1, Rab3a, Syn2, Syn1, Cask, Lin7b were most associated with SCI. Finally, these hub genes were further verified by quantitative real-time fluorescence polymerase chain reaction (qRT-PCR) in the spinal cord tissues of the blank group and SCI rats, and it was found that the expression of these hub genes was significantly decreased in the spinal cord injury compared with the blank group (P ≤ 0.05).

CONCLUSION

These results suggest that the structure and function of synapses play an important role after spinal cord injury. Our study helps to understand the underlying pathogenesis of SCI patients further and identify new targets for SCI treatment.

International classification of functioning, disability and health with long-term consequences of cranio-brain injury

OBJECTIVE

Aim: To describe health status and related functioning of patients with different severity of traumatic brain injury (TBI) in past medical history in Ukraine and determining the feasibility of using the International Classification of Functioning, Disability and Health (ICF) Brief Core Set for TBI.

PATIENTS AND METHODS

Materials and Methods: A total of 102 patients, who were treated in the neurological department of Dnipropetrovsk regional clinical hospital and State Institution ≪Ukrainian State Scientific Research Institute of Medical and Social Problems of Disability of Health Ministry of Ukraine≫, had been examined. Patients were divided into three groups: mild, moderate and severe TBI in past history and evaluated using ICF Brief Core Set for TBI.

RESULTS

Results: Тhe most common problems in the functioning and health of patients in remote period of TBI, along with the influencing factors have been identified in the study. The most frequent categories from ≪Body Functions≫ and ≪Activity and Participation≫ sections in which patients had alterations were: memory functions, emotional functions, sensation of pain, functions of attention, brain structure, complex interpersonal interactions, family relationships. The increase in the amount and severity of disturbances with increasing severity of TBI had been established in all categories, except complex interpersonal interactions and family relationships.

CONCLUSION

Conclusions: Patients of all groups identified the family and close relatives, healthcare service and social welfare services, as the most frequent relieving factors of life activity. The use of the ICF Brief Core Set for assessing the subjects with TBI in past history provides a convenient procedure to standardize and structure functioning description. Information collected by the ICF Brief Core Set may be used for different purposes: clinical assessment, administration of medical services, planning and implementation of rehabilitation and evaluation of results, in scientific research, reports and health care statistics.

Traumatic Brain Injury-Induced Fear Generalization in Mice Involves Hippocampal Memory Trace Dysfunction and Is Alleviated by (R,S)-Ketamine

BACKGROUND

Traumatic brain injury (TBI) is a debilitating neurological disorder caused by an impact to the head by an outside force. TBI results in persistent cognitive impairments, including fear generalization and the inability to distinguish between aversive and neutral stimuli. The mechanisms underlying fear generalization have not been fully elucidated, and there are no targeted therapeutics to alleviate this symptom of TBI.

METHODS

To identify the neural ensembles mediating fear generalization, we utilized ArcCreERT2 × enhanced yellow fluorescent protein (EYFP) mice, which allow for activity-dependent labeling and quantification of memory traces. Mice were administered a sham surgery or the controlled cortical impact model of TBI. Mice were then administered a contextual fear discrimination paradigm and memory traces were quantified in numerous brain regions. In a separate group of mice, we tested if (R,S)-ketamine could decrease fear generalization and alter the corresponding memory traces in TBI mice.

RESULTS

TBI mice exhibited increased fear generalization when compared with sham mice. This behavioral phenotype was paralleled by altered memory traces in the dentate gyrus, CA3, and amygdala, but not by alterations in inflammation or sleep. In TBI mice, (R,S)-ketamine facilitated fear discrimination, and this behavioral improvement was reflected in dentate gyrus memory trace activity.

CONCLUSIONS

These data show that TBI induces fear generalization by altering fear memory traces and that this deficit can be improved with a single injection of (R,S)-ketamine. This work enhances our understanding of the neural basis of TBI-induced fear generalization and reveals potential therapeutic avenues for alleviating this symptom.

Mild Traumatic Brain Injury as a Risk Factor for Parkinsonism, Tics, and Akathisia: A Systematic Review and Meta-Analysis

This meta-analysis aimed to assess the association between mild traumatic brain injury (mTBI) and the risk of developing Parkinsonism. A systematic literature review was conducted using PubMed, Embase, and Cochrane Library databases. Studies were eligible if they reported on the association between MTBI and Parkinsonism. Pooled odds ratios (ORs) were calculated using a random-effects model. Publication bias was assessed using Egger's and Begg's tests. A total of 18 studies were included in this meta-analysis, with 1,484,752 participants. The overall OR for Parkinsonism in individuals with a history of mTBI was 1.637 (95% CI, 1.203-2.230; p = 0.01), indicating a significant association. The OR for Parkinson's disease (PD) specifically was 1.717 (95% CI, 1.206-2.447; p = 0.01). However, insufficient data on tics and akathisia limited a meta-analysis. There was no evidence of publication bias according to Egger's (p = 0.8107) and Begg's (p = 0.4717) tests. This meta-analysis provides evidence that mTBI is a significant risk factor for Parkinsonism, particularly PD. However, the findings should be interpreted with caution due to the heterogeneity among the studies included and the study's limitations. Further research is needed to confirm these findings and to investigate the underlying mechanisms of the mTBI-Parkinsonism association.

Fingolimod (FTY720) Hinders Interferon-γ-Mediated Fibrotic Scar Formation and Facilitates Neurological Recovery After Spinal Cord Injury

Following spinal cord injury (SCI), fibrotic scar inhibits axon regeneration and impairs neurological function recovery. It has been reported that T cell-derived interferon (IFN)-γ plays a pivotal role in promoting fibrotic scarring in neurodegenerative disease. However, the role of IFN-γ in fibrotic scar formation after SCI has not been declared. In this study, a spinal cord crush injury mouse was established. Western blot and immunofluorescence showed that IFN-γ was surrounded by fibroblasts at 3, 7, 14, and 28 days post-injury. Moreover, IFN-γ is mainly secreted by T cells after SCI. Further, in situ injection of IFN-γ into the normal spinal cord resulted in fibrotic scar formation and inflammation response at 7 days post-injection. After SCI, the intraperitoneal injection of fingolimod (FTY720), a sphingosine-1-phosphate receptor 1 (S1PR1) modulator and W146, an S1PR1 antagonist, significantly reduced T cell infiltration, attenuating fibrotic scarring via inhibiting IFN-γ/IFN-γR pathway, while in situ injection of IFN-γ diminished the effect of FTY720 on reducing fibrotic scarring. FTY720 treatment inhibited inflammation, decreased lesion size, and promoted neuroprotection and neurological recovery after SCI. These findings demonstrate that the inhibition of T cell-derived IFN-γ by FTY720 suppressed fibrotic scarring and contributed to neurological recovery after SCI.

The incidence of brain trauma caused by road injuries: Results from the Global Burden of Disease Study 2019

BACKGROUND

Road collisions are a significant source of traumatic brain injury (TBI). We aimed to determine the pattern of road injury related TBI (RI-TBI) incidence, as well as its temporal trends.

METHODS

We collected detailed information on RI-TBI between 1990 and 2019, derived from the Global Burden of Disease Study 2019. Estimated annual percentage changes (EAPCs) of RI-TBI age standardized incidence rate (ASIR), by sex, region, and cause of road injuries, were assessed to quantify the temporal trends of RI-TBI burden.

RESULTS

Globally, incident cases of RI-TBI increased 68.1% from 6,900,000 in 1990 to 11,600,000 in 2019. The overall ASIR increased by an average of 0.43% (95% CI 0.30%-0.56%) per year during this period. The ASIR of RI-TBI due to cyclist, motorcyclist and other road injuries increased between 1990 and 2019; the corresponding EAPCs were 0.56 (95% CI 0.37-0.75), 1.60 (95% CI 1.35-1.86), and 0.75 (95% CI 0.59-0.91), respectively. In contrast, the ASIR of RI-TBI due to motor vehicle and pedestrian decreased with an EAPC of -0.12 and -0.14 respectively. The changing pattern for RI-TBI was heterogeneous across countries and regions. The most pronounced increases were observed in Mexico (EAPC = 3.74), followed by China (EAPC = 2.45) and Lesotho (EAPC = 1.91).

CONCLUSIONS

RI-TBI remains a major public health concern worldwide, although road safety legislations have contributed to the decreasing incidence in some countries. We found an unfavorable trend in several countries with a relatively low socio-demographic index, suggesting that much more targeted and specific approaches should be adopted in these areas to forestall the increase in RI-TBI.

Sonographic Evaluation of Deep Vein Thrombosis in Hospitalized Neurosurgical Trauma Patients in Ibadan, Nigeria

BACKGROUND

Deep vein thrombosis (DVT) is a major cause of morbidity and mortality in hospitalized trauma patients. Ultrasonography (US) has replaced venography as the initial diagnostic tool for DVT.

AIMS

The study aimed to determine the incidence of lower limb DVT in hospitalized neurosurgical trauma patients in hospitalized neurosurgical patients. It also aimed to determine the effect of combined thrombo-prophylaxis on the incidence of lower limb deep DVT relative to a single regimen.

PATIENTS AND METHODS

This was a prospective study of 154 adult neurotrauma patients who consecutively had lower limb Doppler ultrasound, initially within 72 hours of admissions and subsequently weekly or when DVT was suspected for the first 3 weeks of admission. The study spanned a 12-month period. The data generated were analyzed using the statistical package for social sciences software version 20, Chicago IL. Inc. Chi-square test was used to compare the outcome (DVT incidence) between single and combined prophylaxis groups.

RESULTS

The study participants consisted of 116 (75.3%) and 38 (24.7%) cases of head and spine injuries, respectively, with a mean age of 38.8 ± 6.3 years and 85.1% being males. A total of four cases of DVT were detected during the study period, with the majority of the cases (3) detected within the first week of admission, giving an incidence of 2.6%. All four cases of DVT were detected in patients on single thrombo-prophylaxis (4/55 = 7.3%), while none was found in those on a combined regimen (0/34, P = 0.046).

CONCLUSION

Most cases of DVT developed in the first week of hospitalization. Combined thrombo-prophylaxis was more effective than single regimen at reducing rate of DVT in neurosurgical trauma patients. Routine Doppler ultrasound DVT surveillance should be part of the management protocol for neurosurgical trauma patients on admission to increase DVT detection and prevent possible fatal pulmonary embolism.

Artificially reprogrammed stem cells deliver transcytosable nanocomplexes for improved spinal cord repair

Stem cell transplantation holds great promise for restoring function after spinal cord injury (SCI), but its therapeutic efficacy heavily depends on the innate capabilities of the cells and the microenvironment at the lesion site. Herein, a potent cell therapeutic (NCs@SCs) is engineered by artificially reprogramming bone marrow mesenchymal stem cells (BMSCs) with oxidation-responsive transcytosable gene-delivery nanocomplexes (NCs), which endows cells with robust oxidative stress resistance and improved cytokine secretion. NCs@SCs can accumulate in the injured spinal cord after intravenous administration via chemotaxis and boost successive transcytosis to deliver NCs to neurons, augmenting ciliary neurotrophic factor (CNTF) production in both BMSCs and neurons in response to elevated ROS levels. Furthermore, NCs@SCs can actively sense and eliminate ROS and re-educate recruited M1-like macrophages into the anti-inflammatory M2 phenotype via a paracrine pathway, ultimately reshaping the inflammatory microenvironment. Synergistically, NCs@SCs exhibit durable survival and provide neuroprotection against secondary damage, enabling significant locomotor function recovery in SCI rats. Transcriptome analysis reveals that regulation of the ROS/MAPK signaling pathway is involved in SCI therapy by NCs@SCs. This study presents a nanomaterial-mediated cell-reprogramming approach for developing live cell therapeutics, showing significant potential in the treatment of SCI and other neuro-injury disorders.

Evidence-based management of adult traumatic brain injury with raised intracranial pressure in intensive critical care unit at resource-limited settings: a literature review

Background

In underdeveloped countries, there is a greater incidence of mortality and morbidity arising from trauma, with traumatic brain injury (TBI) accounting for 50% of all trauma-related deaths. The occurrence of elevated intracranial pressure (ICP), which is a common pathophysiological phenomenon in cases of TBI, acts as a contributing factor to unfavorable outcomes. The aim of this systematic review is to analyze the existing literature regarding the management of adult TBI with raised ICP in an intensive critical care unit, despite limited resources.

Methods

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis protocol. Search engines such as PubMed, the Cochrane database, and Google Scholar were utilized to locate high-level evidence that would facilitate the formation of sound conclusions.

Result

A total of 11 715 articles were identified and individually assessed to determine their eligibility for inclusion or exclusion based on predetermined criteria and outcome variables. The methodological quality of each study was evaluated using recommended criteria. Ultimately, the review consisted of 51 articles.

Conclusion

Physical examination results and noninvasive assessments of the optic nerve sheath diameter (ONSD) via sonography are positively associated with elevated ICP, and are employed as diagnostic and monitoring tools for elevated ICP in resource-limited settings. Management of elevated ICP necessitates an algorithmic approach that utilizes prophylactic measures and acute intervention treatments to mitigate the risk of secondary brain injury.

Burden and predictions of hospitalized injuries in a low-middle income country: results from a Tunisian university hospital

Injuries are responsible for a high premature mortality and disability. They are poorly explored in low and middle income-countries. We aimed to estimate the burden of hospitalized injuries in the Monastir governorate (Tunisia) according to the nature of the injury, trends and projections of hospitalizations for injuries up until 2024, and to identify the distribution of this disease burden based on age and sex. We performed a descriptive study from 2002 to 2012 including all hospitalizations for injuries. Data were collected from morbidity and mortality register of the University Hospital of Monastir (Tunisia). We estimated the burden of injuries using the Disability Adjusted Life Years (DALYs). We described injuries (crude prevalence rate (CPR) and age standardized prevalence rate (ASR)), related mortality (lethality and standardized mortality ratio (SMR)), trends and prediction for 2024. A total of 18,632 hospitalizations for injuries representing 10% of all hospitalizations during study period were recorded. Per 1000 inhabitants per year, CPR was 3.36 and the ASR was 3.44. The lethality was of 17.5 deaths per 1000 injured inpatients per year and the SMR was of 2.95 (Confidence Interval of 95%: 2.64-3.29). Burden related to injuries was 2.36 DALYs per 1000 population per year, caused mainly by Years of Life Lost (83.4%), most frequent among men aged under 40 years. The predicted ASR for 2024 was 4.46 (3.81-5.23) per 1000 person-years. Injuries to the head was the most prevalent (20.7%) causing 67.7% of DALYs; and increasing by 226% through 2024. Injuries had a high prevalence and an important burden in a Tunisian university hospital. Prediction showed increased prevalence for 2024. Preventive measures and a trauma surveillance register should be implemented soon.

Schwann Cell-Derived Exosomes and Methylprednisolone Composite Patch for Spinal Cord Injury Repair

Spinal cord injury (SCI) can cause permanent loss of sensory and motor function, and there is no effective clinical treatment, to date. Due to the complex pathological process involved after injury, synergistic treatments are very urgently needed in clinical practice. We designed a nanofiber scaffold hyaluronic acid hydrogel patch to release both exosomes and methylprednisolone to the injured spinal cord in a non-invasive manner. This composite patch showed good biocompatibility in the stabilization of exosome morphology and toxicity to nerve cells. Meanwhile, the composite patch increased the proportion of M2-type macrophages and reduced neuronal apoptosis in an in vitro study. In vivo, the functional and electrophysiological performance of rats with SCI was significantly improved when the composite patch covered the surface of the hematoma. The composite patch inhibited the inflammatory response through macrophage polarization from M1 type to M2 type and increased the survival of neurons by inhibition neuronal of apoptosis after SCI. The therapeutic effects of this composite patch can be attributed to TLR4/NF-κB, MAPK, and Akt/mTOR pathways. Thus, the composite patch provides a medicine-exosomes dual-release system and may provide a non-invasive method for clinical treatment for individuals with SCI.

Iron overload enhances TBI-induced cardiac dysfunction by promoting ferroptosis and cardiac inflammation

Previous studies have proved that cardiac dysfunction and myocardial damage can be found in TBI patients, but the underlying mechanisms of myocardial damage induced by TBI can't be illustrated. We want to investigate the function of ferroptosis in myocardial damage after TBI and determine if inhibiting iron overload might lessen myocardial injury after TBI due to the involvement of iron overload in the process of ferroptosis and inflammation. We detect the expression of ferroptosis-related proteins in cardiac tissue at different time points after TBI, indicating that TBI can cause ferroptosis in the heart in vivo. The echocardiography and myocardial enzymes results showed that ferroptosis can aggravate TBI-induced cardiac dysfunction. The result of DHE staining and 4-HNE expression showed that inhibition of ferroptosis can reduce ROS production and lipid peroxidation in myocardial tissue. In further experiments, DFO intervention was used to explore the effect of iron overload inhibition on myocardial ferroptosis after TBI, the production of ROS, expression of p38 MAPK and NF-κB was detected to explore the effect of iron overload on myocardial inflammation after TBI. The results above show that TBI can cause heart ferroptosis in vivo. Inhibition of iron overload can alleviate myocardial injury after TBI by reducing ferroptosis and inflammatory response induced by TBI.

Cognitive biases regarding utilization of emergency severity index among emergency nurses

AIM

The study aimed to measure emergency nurses' prevalence of cognitive biases when utilizing Emergency Severity Index (ESI). Moreover, the study aimed to measure the differences between cognitive biases and demographic variables.

BACKGROUND

Nurses use Emergency Severity Index (ESI) to prioritize the patients. Cognitive biases could compromise the clinical decisions of nurses in triage. Consequently, this hinders the delivery of safe and quality patient care.

METHODS

A cross-sectional analytical approach invited 208 emergency nurses from four tertiary care hospitals. Institutional review board approval and permission from institutional heads were obtained. Informed consent was attained before data collection. Data was collected through a structured scenario-based questionnaire to measure cognitive biases at five levels of ESI. Descriptive and inferential statistics were obtained through v25.0 of SPSS.

RESULTS

Among the 86.6% response rate, 56.2% of nurses were male. 62.90% had nursing diplomas. Cognitive biases were present at all ESI levels one to five, in order 51%, 45%, 90%, 89%, and 91% among nurses. Premature closure 22%, tolerance to risk 12%, satisfying bias 25%, framing effect 22%, and blind obedience 34% from level one to five consecutively. Demographic variables, including males, experience between 2 and 5 years, general nursing as qualification, and without emergency severity index certification, were identified to encounter more cognitive biases when making triage decisions.

CONCLUSION

Numerous cognitive biases are considerably existing among emergency nurses when prioritizing patients. Cognitive de-biasing measures can improve triage decisions among nurses that could enhance quality care and patient safety.

A placebo-controlled randomized clinical trial of amantadine hydrochloride for evaluating the functional improvement of patients following severe acute traumatic brain injury

BACKGROUND

Considering the known derangements in the dopaminergic neurotransmitter systems following traumatic brain injury (TBI), dopamine agonists are used as a pharmacologic option. In this study, we evaluate the effects of amantadine hydrochloride on the functional improvement of severe TBI patients.

METHODS

Within a triple-blinded (patients, intervention administrators, and outcome assessors) placebo-controlled randomized clinical trial, we evaluated the effects of amantadine (100 mg BD (twice a day) for 14 days, then 150 mg BD for another 7 days, and 200 mg BD for another 21 days) on outcome measurements of weekly mean Glasgow Outcome Scale (GOS) and Disability Rating Scale (DRS), through six weeks of trial for 57 patients (29 amantadine, 28 placeboes) with severe TBI admitted in our hospital.

RESULTS

Although both groups had improvement in their DRS, the change from baseline was significantly better in the amantadine group (10.88±5.24 for amantadine vs. 8.04±4.07 for placebo, P=0.015). No significant difference was observed between groups for GOS (1.04±0.55 for amantadine vs. 1.12±1.05 for placebo, P=0.966).

CONCLUSIONS

Based on our findings, amantadine hydrochloride might improve the speed of functional ability improvement in severe TBI patients, evaluated by DRS, and is also well tolerated by patients. Although, there were some limitations in this study, including small sample size, short time interval, not providing a wash-off period and invalidity of GOS for measuring recovery rates in short-term periods.

Outcomes and associated factors of traumatic brain injury among adult patients treated in Amhara regional state comprehensive specialized hospitals

BACKGROUND

Globally, traumatic brain injury is the leading cause of death and disability which affects more than 69 million individuals a year.

OBJECTIVE

This study aimed to assess the outcome and associated factors of traumatic brain injury among adult patients treated in Amhara regional state comprehensive specialized hospitals.

METHOD

Institutional-based cross-sectional study design was conducted from January 1, 2018, to December 30, 2020. A simple random sampling technique was used and a checklist was used to extract data between March 15 and April 15, 2021. The data were entered into Epi-data version 4.2 and exported to SPSS version 25 for analysis after being checked for consistency. Associated variables with outcomes of traumatic brain injury were determined by a binary logistic regression model. The degree of association was interpreted by using AOR and a 95% confidence interval with a p-value less than or equal to 0.05 at 95% CI was considered statistically significant.

RESULT

In this study road traffic injury was the most frequent cause of traumatic brain injuries among adult patients, accounting for 181 (37.5%), followed by assault, accounting for 117 (24.2%) which affects adult age groups. One-third of the participant had a moderate Glasgow coma scale of 174(36%). Only 128(26.8%) patients arrived within one hour. One hundred sixty, 160 (33.1%) of patients had a mild traumatic brain injury, whereas, 149(36%) of patients had a severe traumatic brain injury. Regarding computerized tomography scans findings, the hematoma was the most common (n = 163, 33.7%). Ninety-one, 91(18.8%) of participants had cerebrospinal fluid otorrhea, and, 92(19%) were diagnosed with a positive battle sign. The overall prevalence of unfavorable outcomes after traumatic brain injury was found to be 35.2% (95%CI (30.8-39.1). Having additional Injury, hypoxia, time to hospital presentation after 24 h, severe Glasgow Coma Scale, moderate Glasgow Coma Scale, tachypnea, bradypnea, and cerebrospinal fluid Othorrhea, were factors associated with unfavorable outcomes.

CONCLUSION AND RECOMMENDATION

In this study, the overall unfavorable outcome was experienced by about four out of every 10 victims of traumatic brain injury. Time of arrival > 24 h, low Glasgow coma scale, additional injury, Cerebrospinal fluid otorrhea, abnormal respiration, and hypoxia were significant predictors of unfavorable outcomes. To reduce the adverse effects of traumatic brain injury in adults, it is therefore desirable to guarantee safe road traffic flow and improve health care services.

Cardiovascular events in children with brain injury: A systematic review

BACKGROUND

Brain injury is a leading cause of morbidity and mortality in the pediatric population. Neurogenic stunned cardiomyopathy is a complication associated with several neurological conditions that can lead to worse outcomes. It presents as alterations in blood pressure, cardiac rhythm disturbances and the increase in cardiac injury biomarkers. This systematic review aims to assess the hemodynamic consequences of brain injury in the pediatric population to identify better management strategies and improve outcomes.

METHODS

An electronic literature search was performed in Pubmed, Scopus and WebOfScience, up until October 3rd, 2022. The selected articles underwent quality assessment using the National Heart, Lung and Blood Institute tools for cohort and case-control studies.

RESULTS

This systematic review includes thirteen articles on the effects of brain injury in arterial pressure, rhythm disturbances and biomarkers of myocardial injury. These studies showed the following key results: both hypotension and hypertension are associated with worse outcomes; brain injury could be related to longer QTc intervals; neurogenic stunned cardiomyopathy was a common found after brain injury.

CONCLUSION

This is the first systematic review to report cardiovascular abnormalities arising from brain injury in children. An early arterial pressure, electrocardiographic and echocardiographic evaluation, as well as the measure of serum biomarkers for myocardial injury, can be critical in identifying poor prognostic factors. Further research is required to understand the implications of our findings in clinical practice.

Outcome of 1939 traumatic brain injury patients from road traffic accidents: Findings from specialist medical reports in a low to middle income country (LMIC)

OBJECTIVE

Road traffic accident (RTA) is the major cause of traumatic brain injury (TBI) in developing countries and affects mostly young adult population. This research aimed to describe the factors predicting functional outcome after TBI caused by RTA in a Malaysian setting.

METHODS

This was a retrospective cross-sectional study conducted on specialist medical reports written from 2009 to 2019, involving patients who survived after TBI from RTA. The functional outcome was assessed using the Glasgow Outcome Scale-Extended (GOSE). Factors associated with good outcome were analysed via logistic regression analysis. Multivariate logistic regression analysis was used to derive the best fitting Prediction Model and split-sample cross-validation was performed to develop a prediction model.

RESULTS

A total of 1939 reports were evaluated. The mean age of the study participants was 32.4 ± 13.7 years. Most patients were male, less than 40, and with average post RTA of two years. Good outcome (GOSE score 7 & 8) was reported in 30.3% of the patients. Factors significantly affecting functional outcome include age, gender, ethnicity, marital status, education level, severity of brain injury, neurosurgical intervention, ICU admission, presence of inpatient complications, cognitive impairment, post-traumatic headache, post traumatic seizures, presence of significant behavioural issue; and residence post discharge (p<0.05). After adjusting for confounding factors, prediction model identified age less than 40, mild TBI, absence of post traumatic seizure, absence of behaviour issue, absence of cognitive impairment and independent living post TBI as significant predictors of good functional outcome post trauma. Discrimination of the model was acceptable (C-statistic, 0.67; p<0.001, 95% CI: 0.62-0.73).

CONCLUSION

Good functional outcome following TBI due to RTA in this study population is comparable to other low to middle income countries but lower than high income countries. Factors influencing outcome such as seizure, cognitive and behavioural issues, and independent living post injury should be addressed early to achieve favourable long-term outcomes.

Intracranial Hypertension following Acute Mesenteric Ischemia: A Case Study on the Multiple Compartment Syndrome

In this case study, we describe a 25-year-old male who was admitted due to a severe traumatic brain injury, requiring invasive intracranial pressure monitoring. At 48 hours posttrauma, he developed intracranial hypertension refractory to medical treatment without tomographic changes in the brain. Subsequently, intra-abdominal hypertension and tomographic signs of abdominal surgical pathology were observed. An exploratory laparotomy was performed with an intraoperative diagnosis of acute mesenteric ischemia. After surgical intervention for the abdominal pathology, intracranial pressure was restored to physiological values with a favorable recovery of the patient. In this report, the relationship between intracranial pressure and intra-abdominal pressure is discussed, highlighting the delicate association between the brain, abdomen, and thorax. Measures should be taken to avoid increases in intra-abdominal pressure in neurocritical patients. When treating intracranial hypertension refractory to conventional measures, abdominal causes and multiple compartment syndrome must be considered. The cranial compartment has physiological interdependence with other body compartments, where one can be modified by variations from another, giving rise to the concept of multiple compartment syndrome. Understanding this relationship is fundamental for a comprehensive approach of the neurocritical patient. To the best of our knowledge, this is the first report of a comatose patient post-traumatic brain injury, who developed medically unresponsive intracranial hypertension secondary to acute mesenteric ischemia, in which surgical resolution of intra-abdominal pathology resulted in intracranial pressure normalization and restitutio ad integrum of neurological status.

Post-mortem detection of neuronal and astroglial biochemical markers in serum and urine for diagnostics of traumatic brain injury

Currently available epidemiological data shows that traumatic brain injury (TBI) represents one of the leading causes of death that is associated with medico-legal practice, including forensic autopsy, criminological investigation, and neuropathological examination. Attention focused on TBI research is needed to advance its diagnostics in ante- and post-mortem cases with regard to identification and validation of novel biomarkers. Recently, several markers of neuronal, astroglial, and axonal injury have been explored in various biofluids to assess the clinical origin, progression, severity, and prognosis of TBI. Despite clinical usefulness, understanding their diagnostic accuracy could also potentially help translate them either into forensic or medico-legal practice, or both. The aim of this study was to evaluate post-mortem pro-BDNF, NSE, UCHL1, GFAP, S100B, SPTAN1, NFL, MAPT, and MBP levels in serum and urine in TBI cases. The study was performed using cases (n = 40) of fatal head injury and control cases (n = 20) of sudden death. Serum and urine were collected within ∼ 24 h after death and compared using ELISA test. In our study, we observed the elevated concentration levels of GFAP and MAPT in both serum and urine, elevated concentration levels of S100B and SPTAN1 in serum, and decreased concentration levels of pro-BDNF in serum compared to the control group. The obtained results anticipate the possible implementation of performed assays as an interesting tool for forensic and medico-legal investigations regarding TBI diagnosis where the head injury was not supposed to be the direct cause of death.

The Role of Substance P Within Traumatic Brain Injury and Implications for Therapy

This review examines the role of the neuropeptide substance P within the neuroinflammation that follows traumatic brain injury. It examines it in reference to its preferential receptor, the neurokinin-1 receptor, and explores the evidence for antagonism of this receptor in traumatic brain injury with therapeutic intent. Expression of substance P increases following traumatic brain injury. Subsequent binding to the neurokinin-1 receptor results in neurogenic inflammation, a cause of deleterious secondary effects that include an increased intracranial pressure and poor clinical outcome. In several animal models of TBI, neurokinin-1 receptor antagonism has been shown to reduce brain edema and the resultant rise in intracranial pressure. A brief overview of the history of substance P is presented, alongside an exploration into the chemistry of the neuropeptide with a relevance to its functions within the central nervous system. This review summarizes the scientific and clinical rationale for substance P antagonism as a promising therapy for human TBI.

Supramolecular assemblies with spatio-temporal sequential drug delivery capability treat spinal cord injury via neuroprotection and immunoregulation

Spinal cord injury (SCI) can result in irreversible motor and sensory deficits. However, up to data, clinical first-line drugs have ambiguous benefits and debilitating side effects, mainly due to the insufficient accumulation, poor physiological barrier penetration, and lack of spatio-temporal controlled release at lesion tissue. Herein, we proposed a supramolecular assemblies composed of hyperbranched polymer-formed core/shell structure through host-guest interactions. Such HPAA-BM@CD-HPG-C assemblies co-loaded with p38 inhibitor (SB203580) and insulin-like growth factor 1(IGF-1) are able to achieve time- and space-programmed sequential delivery benefiting from their cascaded responsiveness. The core-shell disassembly of HPAA-BM@CD-HPG-C occurs in acidic micro-environment around lesion, achieving preferentially the burst release of IGF-1 to protect survival neurons. Subsequently, the HPAA-BM cores containing SB203580 are endocytosed by the recruited macrophages and degraded by intracellular GSH, accelerating the release of SB203580 to promote the conversion from M1 to M2 macrophage. Hence, the successive synergy of neuroprotection and immunoregulation effects contribute to subsequent nerve repair and locomotor recovery as demonstrated in vitro and in vivo studies. Thus, our fabrication provides a strategy that multiple drugs co-delivery in a spatio-temporal selective manner adapting to the disease progression through self-cascaded disintegration, are expected to realize multidimensional precise treatment of SCI.

Clinical outcomes and prognostic factors of traumatic basal ganglia hematomas: A 4-year single-center study

BACKGROUND

Traumatic basal ganglia hematomas (TBGH) are rare entities. They are situated in the deep cerebral parenchyma and have also been termed as intermediate coup contusions. Available literature is sparse with regards to the characteristics and prognosis of TBGH. We aim to share our experience in the management, outcomes, and prognostic factors of TBGH.

METHODS

A 4-year retrospective study which included all cases of TBGH, except dot contusions (<2 mL) and those with coagulopathies. Admission variables were correlated with Glasgow Outcome Scale score at discharge and 12 months.

RESULTS

Thirty-two patients were analyzed. The mean age was 39.2 years. Two-thirds were due to road traffic accidents. Around 60% were severe head injuries. The mean Glasgow coma scale (GCS) score at presentation was 8.5. Twenty patients had moderate-to-severe hemiparesis. The mean hematoma volume was 18.1 mL. Associated traumatic intracranial lesions were seen in 28 cases. Only 7 patients (22%) underwent surgery. The mean follow-up was 17.4 months (range 14-34 months). The mortality rate was 12.5% (n = 4). Among the survivors, only 39% (n = 11) had good outcomes at discharge which showed modest improvement to 54% (n = 15) at 12 months.

CONCLUSION

Our study noted that poor admission GCS scores, poor motor response, presence of significant hemiparesis, and larger hematoma volumes (>20 mL) correlated with poor outcomes at 12 months. The overall outcomes have been mostly unfavorable as observed in majority of studies due to deeper location of these hematomas, high proportion of severe head injuries, and high proportion of residual weakness in survivors.

Towards modern post-coma care based on neuroscientific evidence

Background

Understanding the mechanisms underlying human consciousness is pivotal to improve the prognostication and treatment of severely brain-injured patients. Consciousness remains an elusive concept and the identification of its neural correlates is an active subject of research, however recent neuroscientific advances have allowed scientists to better characterize disorders of consciousness. These breakthroughs question the historical nomenclature and our current management of post-comatose patients.

Method

This review examines the contribution of consciousness neurosciences to the current clinical management of severe brain injury. It investigates the major impact of consciousness disorders on healthcare systems, the scientific frameworks employed to identify their neural correlates and how evidence-based data from neuroimaging research have reshaped the landscape of post-coma care in recent years.

Results

Our increased ability to detect behavioral and neurophysiological signatures of consciousness has led to significant changes in taxonomy and clinical practice. We advocate for a multimodal framework for the management of severely brain-injured patients based on precision medicine and evidence-based decisions, integrating epidemiology, health economics and neuroethics.

Conclusions

Major progress in brain imaging and clinical assessment have opened the door to a new era of post-coma care based on standardized neuroscientific evidence. We highlight its implications in clinical applications and call for improved collaborations between researchers and clinicians to better translate findings to the bedside.

Epidemiological study of paediatric traumatic brain injury in Brazil

Background

Traumatic brain injury (TBI) has a high economic and social impact on the family dynamics, particularly among children. High-quality and comprehensive epidemiological studies about TBI in this population are limited worldwide, specifically in Latin America. Therefore, this study aimed to elucidate the epidemiology of TBI among children in Brazil and its effects on the public health system.

Methods

This epidemiological (cohort) retrospective study collected data from the Brazilian healthcare database between 1992 and 2021.

Results

The mean annual volume of hospital admission (HA) due to TBI in Brazil was 29,017. Moreover, the incidence of TBI in the paediatric population was 45.35 admissions per 100,000 inhabitants/year. Furthermore, approximately 941 paediatric hospital deaths per year were caused by TBI, with an in-hospital lethality rate of 3.21%. The average annual financial transfer for TBI was 12,376,628 USD, and the mean cost per admission was 417 USD. In addition, the mean length of hospital stay was 4.2 days. Notably, the length of stay in the hospital was longer among males, Afro-Brazilians patients and individuals aged 15-19 years.

Conclusion

Paediatric TBI is an important public health issue worldwide with high social and economic costs. The incidence of paediatric TBI in Brazil is similar to that in developing countries. Moreover, male predominance (2.3:1) was observed in relation paediatric TBI. Notably, during the pandemic, the incidence of paediatric HA has decreased. To the best of our knowledge, this is the first epidemiological study that specifically evaluates paediatric TBI in Latin America.

Nervous tract-bioinspired multi-nanoyarn model system regulating neural differentiation and its transcriptional architecture at single-cell resolution

Bioinspired by native nervous tracts, a spinal cord-mimicking model system that was composed of multiple nanofibrous yarns (NYs) ensheathed in a nanofibrous tube was constructed by an innovative electrospinning-based fabrication and integration strategy. The infilling NYs exhibited uniaxially aligned nanofibrous architecture that had a great resemblance to spatially-arranged native nervous tracts, while the outer nanofibrous tubes functioned as an artificial dura matter to provide a stable intraluminal microenvironment. The three-dimensional (3D) NYs were demonstrated to induce alignment, facilitate migration, promote neuronal differentiation, and even phenotypic maturation of seeded neural stem and progenitor cells (NSPCs), while inhibiting gliogenesis. Single-cell transcriptome analysis showed that the NSPC-loaded 3D NY model shared many similarities with native spinal cords, with a great increase in excitatory/inhibitory (EI) neuron ratio. Curcumin, as a model drug, was encapsulated into nanofibers of NYs to exert an antioxidant effect and enhanced axon regeneration. Overall, this study provides a new paradigm for the development of a next-generation in vitro neuronal model system via anatomically accurate nervous tract simulation and constructs a blueprint for the research on NSPC diversification in the biomimetic microenvironment.

Neurosurgical Emergencies in the Amazon: An Epidemiologic Study of Patients Referred by Air Transport for Neurosurgical Evaluation at a Referral Center in Amazonas

BACKGROUND

Amazonas is the largest state in Brazil, covering an area of 1,559,159.148 km2 and primarily occupied by the Amazon rainforest. Fluvial and aerial transport are the primary means of transportation. Studying the epidemiologic profile of patients transported by neurologic emergencies is essential because there is only 1 referral center hospital serving approximately 4 million inhabitants in Amazonas.

METHODS

This work studies the epidemiologic profile of patients referred by air transport for evaluation by the neurosurgery team at a referral center in the Amazon.

RESULTS

Of the 68 patients transferred, 50 (75.53%) were men. The study covered 15 municipalities in Amazonas. Of the patients, 67.64% had a traumatic brain injury due to various causes, and 22.05% had had a stroke. Of all patients, 67.65% did not undergo surgery and 43.9% evolved with good evolution and without complications.

CONCLUSIONS

Air transportation for neurologic evaluation is essential in Amazonas. However, most patients did not require neurosurgical intervention, indicating that investments in medical infrastructures, such as computed tomography scanners and telemedicine, may optimize health costs.

National Trauma Registries in LMICs: Long-Overdue Priority Comment on "Neurotrauma Surveillance in National Registries of Low- and Middle-Income Countries: A Scoping Review and Comparative Analysis of Data Dictionaries"

The burden of trauma-related mortality is inversely related to income on an individual and national scale. Barthélemy et al highlight the significant variation of neurotrauma data included in national injury registries of low- and middle-income countries (LMICs) when compared to the World Health Organization (WHO) minimal dataset for injury (MDI). Moreover, the authors emphasize that the non-existence and underutilization of nationally standardized trauma registries hinder the data-driven identification of factors contributing to neurotrauma and subsequent attempts to improve neurotrauma care. Establishing a nationally standardized trauma registry should be prioritized by all stakeholders involved in curbing trauma-related mortality and building research capacity in LMICs. In this commentary, previous successful efforts to establish and maintain robust registries in LMICs through local and international partnerships are highlighted. The lessons and challenges chronicled in establishing such registries can inform future efforts to implement a nationally standardized trauma registry.

Bioactive Spinal Cord Scaffold Releasing Neurotrophic Exosomes to Promote In Situ Centralis Neuroplasticity

Spinal cord injury (SCI), one of the most serious injuries of the central nervous system, causes physical functional dysfunction and even paralysis in millions of patients. As a matter of necessity, redressing the neuroleptic pathologic microenvironment to a neurotrophic microenvironment is essential in order to alleviate this dilemma and facilitate the recovery of the spinal cord. Herein, based on cell-sheet technology, two functional cell types─uninduced and neural-induced stem cells from human exfoliated deciduous teeth─were formed into a composite membrane that subsequently self-assembled to form a bioactive scaffold with a spinal-cord-like structure, called a spinal cord assembly (SCA). In a stable extracellular matrix microenvironment, SCA continuously released SCA-derived exosomes containing various neurotrophic factors, which effectively promoted neuronal regeneration, axonal extension, and angiogenesis and inhibited glial scar generation in a rat model of SCI. Neurotrophic exosomes significantly improved the pathological microenvironment and promoted in situ centralis neuroplasticity, ultimately eliciting a strong repair effect in this model. SCA therapy is a promising strategy for the effective treatment of SCI based on neurotrophic exosome delivery.

Recent Advances in Nanomedicine Development for Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the major causes of morbidity and mortality worldwide, and it is also a risk factor for neurodegeneration. However, there has not been perceptible progress in treating acute TBI over the last few years, mainly due to the inability of therapeutic drugs to cross the blood-brain barrier (BBB), failing to exert significant pharmacological effects on the brain parenchyma. Recently, nanomedicines are emerging as a powerful tool for the treatment of TBI where nanoscale materials (also called nanomaterials) are employed to deliver therapeutic agents. The advantages of using nanomaterials as a drug carrier include their high solubility and stability, high carrier capacity, site-specific, improved pharmacokinetics, and biodistribution. Keeping these points in consideration, this article reviews the pathophysiology, current treatment options, and emerging nanomedicine strategies for the treatment of TBI. The review will help readers to gain insight into the state-of-the-art of nanomedicine as a new tool for the treatment of TBI.

Implantation with SHED sheet induced with homogenate protein of spinal cord promotes functional recovery from spinal cord injury in rats

Introduction: After spinal cord injury (SCI) occurs, the lesion is in a growth inhibitory microenvironment that severely hinders neural regeneration. In this microenvironment, inhibitory factors are predominant and factors that promote nerve regeneration are few. Improving neurotrophic factors in the microenvironment is the key to treating SCI.

Methods: Based on cell sheet technology, we designed a bioactive material with a spinal cord‐like structure –SHED sheet induced with homogenate protein of spinal cord (hp–SHED sheet). Hp–SHED sheet was implanted into the spinal cord lesion for treating SCI rats with SHED suspensions as a control to investigate the effects on nerve regeneration.

Results: Hp–SHED sheet revealed a highly porous three–dimensional inner structure, which facilitates nerve cell attachment and migration. Hp-SHED sheet in vivo restored sensory and motor functions in SCI rats by promoting nerve regeneration, axonal remyelination, and inhibiting glial scarring.

Discussion: Hp–SHED sheet maximally mimics the microenvironment of the natural spinal cord and facilitate cell survival and differentiation. Hp–SHED sheet could release more neurotrophins and the sustained action of neurotrophins improves the pathological microenvironment, which effectively promotes nerve regeneration, axonal extension, and inhibits glial scarring, thereby promoting the in situ centralis neuroplasticity. Hp–SHED sheet therapy is a promising strategy for effective treatment of SCI based on neurotrophins delivery.

Inhibition of Astrocytic Carbohydrate Sulfotransferase 15 Promotes Nerve Repair After Spinal Cord Injury via Mitigation of CSPG Mediated Axonal Inhibition

Nerve tissue regeneration is a significant problem. After neural diseases and damage such as spinal cord injury (SCI), the accumulation of chondroitin sulfate proteoglycans (CSPG) comprising axonal inhibitory glycosaminoglycan chains in the microenvironment is a major barrier that obstructs nerve repair. Interfering with the production of glycosaminoglycans, especially the critical inhibitory chains, could be a potential therapeutic strategy for SCI, which is, however, poorly defined. This study identifies Chst15, the chondroitin sulfotransferase controlling the generation of axonal inhibitory chondroitin sulfate-E, as a therapeutic target of SCI. Using a recently reported small molecular Chst15 inhibitor, this study investigates the effects of Chst15 inhibition on astrocyte behaviors and the associated consequences of in vivo disruption of the inhibitory microenvironment. Deposition of CSPGs in the extracellular matrix and migration of astrocytes are both significantly impaired by Chst15 inhibition. Administration of the inhibitor in transected spinal cord tissues of rats effectively promotes motor functional restoration and nerve tissue regeneration by a mechanism related to the attenuation of inhibitory CSPGs, glial scar formation and inflammatory responses. This study highlights the role of Chst15 in the CSPG-mediated inhibition of neural recovery after SCI and proposes an effective neuroregenerative therapeutic strategy that uses Chst15 as a potential target.

Cerebrospinal fluid-derived extracellular vesicles after spinal cord injury promote vascular regeneration via PI3K/AKT signaling pathway

Background

The cerebrospinal fluid (CSF), which surrounds the brain and spinal cord, is predominantly produced by the choroid plexus of the ventricle. Although CSF-derived extracellular vesicles (CSF-EVs) may be utilized as diagnostic and prognostic indicators for illnesses of the central nervous system (CNS), it is uncertain if CSF-EVs may have an impact on neurological function after spinal cord injury (SCI).

Methods

Here, we isolated EVs using ultracentrifugation after extracting CSF from Bama miniature pigs. We then combined CSF-EVs with hydrogel and put it on the spinal cord's surface. To determine if CSF-EVs had an impact on mice's neurofunctional recovery, behavioral evaluations were employed. Both in vitro and in vivo, the effect of CSF-EVs on angiogenesis was assessed. We investigated whether CSF-EVs stimulated the PI3K/AKT pathway to alter angiogenesis using the PI3K inhibitor LY294002.

Results

CSF-EVs were successfully isolated and identified by transmission electron microscope (TEM), nano-tracking analysis (NTA), and western blot. CSF-EVs could be ingested by vascular endothelial cells as proved by in vivo imaging and immunofluorescence. We demonstrated that CSF-EVs derived from pigs with SCI (SCI-EVs) showed a better effect on promoting vascular regeneration as compared to CSF-EVs isolated from pigs receiving laminectomy (Sham-EVs). Behavioral assessments demonstrated that SCI-EVs could dramatically enhance motor and sensory function in mice with SCI. Western blot analysis suggested that SCI-EVs promote angiogenesis by activating PI3K/AKT signaling pathway, and the pro-angiogenetic effect of SCI-EVs was attenuated by the application of the LY294002 (PI3K inhibitor).

Conclusion

Our study revealed that CSF-EVs could enhance vascular regeneration by activating the PI3K/AKT pathway, hence improving motor function recovery after SCI, which may offer potential novel therapeutic options for acute SCI.

The translational potential of this article

This study demonstrated the promotion of vascular regeneration and neurological function of CSF-derived exosomes, which may provide a potential therapeutic approach for the treatment of spinal cord injury.

Trends in Neurotrauma Epidemiology, Management, and Outcomes during the COVID-19 Pandemic in Kigali, Rwanda

National regulations to curb the coronavirus disease 2019 (COVID-19) transmission and health care resource reallocation may have impacted incidence and treatment for neurotrauma, including traumatic brain injury (TBI) and spinal trauma, but these trends have not been characterized in Sub-Saharan Africa. This study analyzes differences in epidemiology, management, and outcomes preceding and during the COVID-19 pandemic for neurotrauma patients in a Rwandan tertiary hospital. The study setting was the Centre Hospitalier Universitaire de Kigali (CHUK), Rwanda's national referral hospital. Adult injury patients presenting to the CHUK Emergency Department (ED) were prospectively enrolled from January 27, 2020 to June 28, 2020. Study personnel collected data on demographics, injury characteristics, serial neurological examinations, treatment, and outcomes. Differences in patients before (January 27, 2020 to March 21, 2020) and during (June 1, 2020 to June 28, 2020) the COVID-19 pandemic were assessed using chi-squared and Mann-Whitney U tests. The study population included 216 patients with neurotrauma (83.8% TBI, 8.3% spine trauma, and 7.9% with both). Mean age was 34.1 years (standard deviation [SD] = 12.5) and 77.8% were male. Patients predominantly experienced injury following a road traffic accident (RTA; 65.7%). Weekly volume for TBI (mean = 16.5 vs. 17.1, p = 0.819) and spine trauma (mean = 2.0 vs. 3.4, p = 0.086) was similar between study periods. During the pandemic, patients had lower Glasgow Coma Scale (GCS) scores (mean = 13.8 vs. 14.3, p = 0.068) and Kampala Trauma Scores (KTS; mean = 14.0 vs. 14.3, p = 0.097) on arrival, denoting higher injury severity, but these differences only approached significance. Patients treated during the pandemic period had higher occurrence of hemorrhage, contusion, or fracture on computed tomography (CT) imaging (47.1% vs. 26.7%, p = 0.003) and neurological decline (18.6% vs. 7.5%, p = 0.016). Hospitalizations also increased significantly during COVID-19 (54.6% vs. 39.9%, p = 0.048). Craniotomy rates doubled during the pandemic period (25.7% vs. 13.7%, p = 0.003), but mortality was unchanged (5.5% vs. 5.7%, p = 0.944). Neurotrauma volume remained unchanged at CHUK during the COVID-19 pandemic, but presenting patients had higher injury acuity and craniotomy rates. These findings may inform care during pandemic conditions in Rwanda and similar settings.

Altered endocannabinoid metabolism compromises the brain-CSF barrier and exacerbates chronic deficits after traumatic brain injury in mice

Endocannabinoids [2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA)], endogenously produced arachidonate-based lipids, are anti-inflammatory physiological ligands for two known cannabinoid receptors, CB1 and CB2, yet the molecular and cellular mechanisms underlying their effects after brain injury are poorly defined. In the present study, we hypothesize that traumatic brain injury (TBI)-induced loss of endocannabinoids exaggerates neurovascular injury, compromises brain-cerebrospinal fluid (CSF) barriers (BCB) and causes behavioral dysfunction. Preliminary analysis in human CSF and plasma indicates changes in endocannabinoid levels. This encouraged us to investigate the levels of endocannabinoid-metabolizing enzymes in a mouse model of controlled cortical impact (CCI). Reductions in endocannabinoid (2-AG and AEA) levels in plasma were supported by higher expression of their respective metabolizing enzymes, monoacylglycerol lipase (MAGL), fatty acid amide hydrolase (FAAH), and cyclooxygenase 2 (Cox-2) in the post-TBI mouse brain. Following increased metabolism of endocannabinoids post-TBI, we observed increased expression of CB2, non-cannabinoid receptor Transient receptor potential vanilloid-1 (TRPV1), aquaporin 4 (AQP4), ionized calcium binding adaptor molecule 1 (IBA1), glial fibrillary acidic protein (GFAP), and acute reduction in cerebral blood flow (CBF). The BCB and pericontusional cortex showed altered endocannabinoid expressions and reduction in ventricular volume. Finally, loss of motor functions and induced anxiety behaviors were observed in these TBI mice. Taken together, our findings suggest endocannabinoids and their metabolizing enzymes play an important role in the brain and BCB integrity and highlight the need for more extensive studies on these mechanisms.

Traumatic Brain Injury: Intraoperative Management and Intensive Care Unit Multimodality Monitoring

Traumatic brain injury is a devastating event associated with substantial morbidity. Pathophysiology involves the initial trauma, subsequent inflammatory response, and secondary insults, which worsen brain injury severity. Management entails cardiopulmonary stabilization and diagnostic imaging with targeted interventions, such as decompressive hemicraniectomy, intracranial monitors or drains, and pharmacological agents to reduce intracranial pressure. Anesthesia and intensive care requires control of multiple physiologic variables and evidence-based practices to reduce secondary brain injury. Advances in biomedical engineering have enhanced assessments of cerebral oxygenation, pressure, metabolism, blood flow, and autoregulation. Many centers employ multimodality neuromonitoring for targeted therapies with the hope to improve recovery.

Traumatic brain injury-induced fear generalization in mice involves hippocampal memory trace dysfunction and is alleviated by ( R,S )-ketamine

INTRODUCTION

Traumatic brain injury (TBI) is a debilitating neurological disorder caused by an impact to the head by an outside force. TBI results in persistent cognitive impairments, including fear generalization, the inability to distinguish between aversive and neutral stimuli. The mechanisms underlying fear generalization have not been fully elucidated, and there are no targeted therapeutics to alleviate this symptom of TBI.

METHODS

To identify the neural ensembles mediating fear generalization, we utilized the ArcCreER T2 x enhanced yellow fluorescent protein (EYFP) mice, which allow for activity-dependent labeling and quantification of memory traces. Mice were administered a sham surgery or the controlled cortical impact (CCI) model of TBI. Mice were then administered a contextual fear discrimination (CFD) paradigm and memory traces were quantified in numerous brain regions. In a separate group of mice, we tested if ( R,S )-ketamine could decrease fear generalization and alter the corresponding memory traces in TBI mice.

RESULTS

TBI mice exhibited increased fear generalization when compared with sham mice. This behavioral phenotype was paralleled by altered memory traces in the DG, CA3, and amygdala, but not by alterations in inflammation or sleep. In TBI mice, ( R,S )-ketamine facilitated fear discrimination and this behavioral improvement was reflected in DG memory trace activity.

CONCLUSIONS

These data show that TBI induces fear generalization by altering fear memory traces, and that this deficit can be improved with a single injection of ( R,S )-ketamine. This work enhances our understanding of the neural basis of TBI-induced fear generalization and reveals potential therapeutic avenues for alleviating this symptom.