Translational Neuroscience Research Research Articles

CSF neurofilament light chain profiling and quantitation in neurological diseases.

Neurofilament light chain is an established marker of neuroaxonal injury that is elevated in CSF and blood across various neurological diseases. It is increasingly used in clinical practice to aid diagnosis and monitor progression and as an outcome measure to assess safety and efficacy of disease-modifying therapies across the clinical translational neuroscience field. Quantitative methods for neurofilament light chain in human biofluids have relied on immunoassays, which have limited capacity to describe the structure of the protein in CSF and how this might vary in different neurodegenerative diseases. In this study, we characterized and quantified neurofilament light chain species in CSF across neurodegenerative and neuroinflammatory diseases and healthy controls using targeted mass spectrometry. We show that the quantitative immunoprecipitation-tandem mass spectrometry method developed in this study strongly correlates to single-molecule array measurements in CSF across the broad spectrum of neurodegenerative diseases and was replicable across mass spectrometry methods and centres. In summary, we have created an accurate and cost-effective assay for measuring a key biomarker in translational neuroscience research and clinical practice, which can be easily multiplexed and translated into clinical laboratories for the screening and monitoring of neurodegenerative disease or acute brain injury.

Macaque Brainnetome Atlas: A multifaceted brain map with parcellation, connection, and histology

The rhesus macaque (Macaca mulatta) is a crucial experimental animal that shares many genetic, brain organizational, and behavioral characteristics with humans. A macaque brain atlas is fundamental to biomedical and evolutionary research. However, even though connectivity is vital for understanding brain functions, a connectivity-based whole-brain atlas of the macaque has not previously been made. In this study, we created a new whole-brain map, the Macaque Brainnetome Atlas (MacBNA), based on the anatomical connectivity profiles provided by high angular and spatial resolution ex vivo diffusion MRI data. The new atlas consists of 248 cortical and 56 subcortical regions as well as their structural and functional connections. The parcellation and the diffusion-based tractography were evaluated with invasive neuronal-tracing and Nissl-stained images. As a demonstrative application, the structural connectivity divergence between macaque and human brains was mapped using the Brainnetome atlases of those two species to uncover the genetic underpinnings of the evolutionary changes in brain structure. The resulting resource includes: (1) the thoroughly delineated Macaque Brainnetome Atlas (MacBNA), (2) regional connectivity profiles, (3) the postmortem high-resolution macaque diffusion and T2-weighted MRI dataset (Brainnetome-8), and (4) multi-contrast MRI, neuronal-tracing, and histological images collected from a single macaque. MacBNA can serve as a common reference frame for mapping multifaceted features across modalities and spatial scales and for integrative investigation and characterization of brain organization and function. Therefore, it will enrich the collaborative resource platform for nonhuman primates and facilitate translational and comparative neuroscience research.

The influence of acute dopamine transporter inhibition on manic-, depressive-like phenotypes, and brain oxidative status in adult zebrafish

Functional changes in dopamine transporter (DAT) are related to various psychiatric conditions, including bipolar disorder (BD) symptoms. In experimental research, the inhibition of DAT induces behavioral alterations that recapitulate symptoms found in BD patients, including mania and depressive mood. Thus, developing novel animal models that mimic BD-related conditions by pharmacologically modulating the dopaminergic signaling is relevant. The zebrafish (Danio rerio) has been considered a suitable vertebrate system for modeling BD-like responses, due to the well-characterized behavioral responses and evolutionarily conservation of the dopaminergic system of this species. Here, we investigate whether GBR 12909, a selective inhibitor of DAT, causes neurobehavioral alterations in zebrafish similar to those observed in BD patients. Behaviors were recorded after a single intraperitoneal (i.p.) administration of GBR 12909 at different doses (3.75, 7.5, 15 and 30 mg/kg). To observe temporal effects on behavior, swim path parameters were measured immediately after the administration period during 30 min. Locomotion, anxiety-like behavior, social preference, aggression, despair-like behavior, and oxidative stress-related biomarkers in the brain were measured 30 min post administration. GBR 12909 induced prominent effects on locomotor activity and vertical exploration during the 30-min period. Hyperactivity was observed in GBR 30 group after 25 min, while all doses markedly reduced vertical drifts. GBR 12909 elicited hyperlocomotion, anxiety-like behavior, decreased social preference, aggression, and induced depressive-like behavior in a behavioral despair task. Depending on the dose, GBR 12909 also decreased SOD activity and TBARS levels, as well as increased GR activity and NPSH content. Collectively, our novel findings show that a single GBR 12909 administration evokes neurobehavioral changes that recapitulate manic- and depressive-like states observed in rodents, fostering the use of zebrafish models to explore BD-like responses in translational neuroscience research.

Multimodal Connectivity-based Individual Parcellation and Analysis for Humans and Rhesus Monkeys.

Individual brains vary greatly in morphology, connectivity and organization. Individualized brain parcellation is capable of precisely localizing subject-specific functional regions. However, most individualization approaches examined single modality of data and have not generalized to nonhuman primates. The present study proposed a novel multimodal connectivity-based individual parcellation (MCIP) method, which optimizes within-region homogeneity, spatial continuity and similarity to a reference atlas with the fusion of personal functional and anatomical connectivity. Comprehensive evaluation demonstrated that MCIP outperformed state-of-the-art multimodal individualization methods in terms of functional and anatomical homogeneity, predictability of cognitive measures, heritability, reproducibility and generalizability across species. Comparative investigation showed a higher topographic variability in humans than that in macaques. Therefore, MCIP provides improved accurate and reliable mapping of brain functional regions over existing methods at an individual level across species, and could facilitate comparative and translational neuroscience research.

Translational neurobiology of zebrafish (<i>Danio rerio</i>)

The zebrafish (Danio rerio) is a small freshwater teleost fish species that is increasingly utilized in biomedical research, particularly in neuroscience and biological psychiatry. Currently, zebrafish is the second-most utilized model organism in biomedicine globally, after mice, based on the number of animals tested each year. The model’s significance results from its experimental ease of use, affordability, conservation of fish physiology, relatively high genetic homology with humans (70%), rapid development, and potential for high-throughput bioscreening of drugs and genetic mutations. Over the past 15 years, our laboratory has conducted extensive experimental work to establish the principles behind using zebrafish to study various brain pathologies, including acute and chronic stress, anxiety, and depression, as well as probing their molecular mechanisms. In addition, existing behavioral models to study the central nervous system (CNS) development and new data on the zebrafish’s critical role in memory research were reviewed. Furthermore, this study will illustrate the effectiveness of integrating zebrafish models with advanced biological research techniques, such as molecular biology, bioinformatics, omics technologies, and chemical biology methods. For example, adult zebrafish experiencing chronic stress exhibit behavioral affective syndromes along with changes in neurochemistry, specifically in the metabolism of serotonin and dopamine in the telencephalon. Moreover, alterations in the expression of genes regulating neurotransmitter receptors, glial biomarkers, cytoskeleton, and pro- and anti-inflammatory cytokines, occur in the brain. In particular, we will focus on neuroimmune and epigenetic mechanisms of CNS pathogenesis in zebrafish models, including changes in the expression of apoptotic genes in the brain. Additionally, our own findings on using artificial intelligence (AI) systems to study zebrafish behavior after administering various neurotropic drugs, such as anxiolytics, antidepressants, psychostimulants, and hallucinogens will be presented. In general, zebrafish is a strategic and promising model organism for translational neuroscience research, creating new models of CNS pathogenesis and finding new drugs to treat various human brain diseases. Studies of CNS pathogenesis in zebrafish are critical because of their evolutionary conservatism and ease of laboratory application, revealing novel brain disease biomarkers and potential remediation targets. Meanwhile, certain distinctive aspects of the biology and neurophysiology of zebrafish facilitate the resolution of supplementary experimental issues, thereby enhancing data and discoveries attained in typical animal models using rodents.

An ultra-compact promoter drives widespread neuronal expression in mouse and monkey brains

Promoters are essential tools for basic and translational neuroscience research. An ideal promoter should possess the shortest possible DNA sequence with cell-type selectivity. However, whether ultra-compact promoters can offer neuron-specific expression is unclear. Here, we report the development of an extremely short promoter that enables selective gene expression in neurons, but not glial cells, in the brain. The promoter sequence originates from the human CALM1 gene and is only 120bp in size. The CALM1 promoter (pCALM1) embedded in an adeno-associated virus (AAV) genome directed broad reporter expression in excitatory and inhibitory neurons in mouse and monkey brains. Moreover, pCALM1, when inserted into an all-in-one AAV vector expressing SpCas9 and sgRNA, drives constitutive and conditional invivo gene editing in neurons and elicits functional alterations. These data demonstrate the ability of pCALM1 to conduct restricted neuronal gene expression, illustrating the feasibility of ultra-miniature promoters for targeting brain-cell subtypes.

Atypical fetal brain development in fetuses with non-syndromic isolated musculoskeletal birth defects (niMSBDs).

Non-syndromic, isolated musculoskeletal birth defects (niMSBDs) are among the leading causes of pediatric hospitalization. However, little is known about brain development in niMSBDs. Our study aimed to characterize prenatal brain development in fetuses with niMSBDs and identify altered brain regions compared to controls. We retrospectively analyzed in vivo structural T2-weighted MRIs of 99 fetuses (48 controls and 51 niMSBDs cases). For each group (19-31 and >31 gestational weeks (GW)), we conducted repeated-measures regression analysis with relative regional volume (% brain hemisphere) as a dependent variable (adjusted for age, side, and interactions). Between 19 and 31GW, fetuses with niMSBDs had a significantly (P < 0.001) smaller relative volume of the intermediate zone (-22.9 ± 3.2%) and cerebellum (-16.1 ± 3.5%,) and a larger relative volume of proliferative zones (38.3 ± 7.2%), the ganglionic eminence (34.8 ± 7.3%), and the ventricles (35.8 ± 8.0%). Between 32 and 37 GW, compared to the controls, niMSBDs showed significantly smaller volumes of central regions (-9.1 ± 2.1%) and larger volumes of the cortical plate. Our results suggest there is altered brain development in fetuses with niMSBDs compared to controls (13.1 ± 4.2%). Further basic and translational neuroscience research is needed to better visualize these differences and to characterize the altered development in fetuses with specific niMSBDs.

Update on Rapid-Eye-Movement Sleep Behavior Disorder (RBD): Focus on Its Strong Association with α-Synucleinopathies

REM sleep behavior disorder (RBD) is a parasomnia in which the customary generalized skeletal muscle atonia of REM sleep, “REM-atonia”, is compromised, allowing for the injurious acting-out of dreams. RBD can be idiopathic/isolated (iRBD) or symptomatic of neurological disorders, and can be triggered by most antidepressants. RBD mainly affects middle-aged and older adults, and is strongly linked with alpha-synucleinopathies, mainly Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). iRBD is now known to be the earliest and strongest predictor of future PD/DLB, which has stimulated a major international clinical and basic science research effort to enroll iRBD patients for upcoming neuroprotective/disease-modifying trials and to identify the most promising interventions to test in these cohorts. This review will provide the latest pertinent information on the rapidly expanding field of RBD. The methods included a PubMed literature search that included PubCrawlers, which utilizes the NCBI (National Center for Biotechnology Information) E-utils tools for publication retrieval, using the keywords “REM sleep behavior disorder” and “RBD”. The results yielded the latest updates on iRBD as prodromal PD/DLB, with the most promising biomarkers for phenoconversion provided, along with a presentation of three clinical research consortiums that are systematically gathering patients in preparation for enrollment in upcoming clinical trials: (i) The International RBD Study Group; (ii) The North American Prodromal Synucleinopathy (NAPS and NAPS2) Consortium; and (iii) The FARPRESTO Italian multicenter RBD research consortium. In addition, updates on the Parasomnia Overlap Disorder (RBD + NREM parasomnia) and on narcolepsy-RBD are provided, along with new epidemiologic data, the latest RBD management guidelines, and updates on animal models of RBD. Emerging areas of critical RBD research are also highlighted. In conclusion, RBD is a notable example of clinical and translational neuroscience research.

Larval zebrafish as a model for studying individual variability in translational neuroscience research.

The larval zebrafish is a popular model for translational research into neurological and psychiatric disorders due to its conserved vertebrate brain structures, ease of genetic and experimental manipulation and small size and scalability to large numbers. The possibility of obtaining in vivo whole-brain cellular resolution neural data is contributing important advances into our understanding of neural circuit function and their relation to behavior. Here we argue that the larval zebrafish is ideally poised to push our understanding of how neural circuit function relates to behavior to the next level by including considerations of individual differences. Understanding variability across individuals is particularly relevant for tackling the variable presentations that neuropsychiatric conditions frequently show, and it is equally elemental if we are to achieve personalized medicine in the future. We provide a blueprint for investigating variability by covering examples from humans and other model organisms as well as existing examples from larval zebrafish. We highlight recent studies where variability may be hiding in plain sight and suggest how future studies can take advantage of existing paradigms for further exploring individual variability. We conclude with an outlook on how the field can harness the unique strengths of the zebrafish model to advance this important impending translational question.

Imaging Approaches to Investigate Pathophysiological Mechanisms of Brain Disease in Zebrafish.

Zebrafish has become an essential model organism in modern biomedical research. Owing to its distinctive features and high grade of genomic homology with humans, it is increasingly employed to model diverse neurological disorders, both through genetic and pharmacological intervention. The use of this vertebrate model has recently enhanced research efforts, both in the optical technology and in the bioengineering fields, aiming at developing novel tools for high spatiotemporal resolution imaging. Indeed, the ever-increasing use of imaging methods, often combined with fluorescent reporters or tags, enable a unique chance for translational neuroscience research at different levels, ranging from behavior (whole-organism) to functional aspects (whole-brain) and down to structural features (cellular and subcellular). In this work, we present a review of the imaging approaches employed to investigate pathophysiological mechanisms underlying functional, structural, and behavioral alterations of human neurological diseases modeled in zebrafish.

Solfeggio-frequency music exposure reverses cognitive and endocrine deficits evoked by a 24-h light exposure in adult zebrafish

Music therapy has long been used as a non-pharmacological intervention to improve cognitive function and mood in humans. Mounting rodent evidence also supports beneficial impact of music exposure on animal cognitive performance. The zebrafish (Danio rerio) is an important emerging aquatic animal model in translational biomedical and neuroscience research. Here, we evaluate the effects of intermittent (2-h or 6-h twice daily) and continuous (24-h) solfeggio-frequency music exposure on behavioral, cognitive and endocrine parameters in adult zebrafish whose circadian rhythm was disturbed by a 24-h light exposure. Overall, a 24-h light exposure stress evokes overt cognitive deficits in the inhibitory avoidance test and elevates zebrafish whole-body cortisol levels. However, these effects were reversed by solfeggio-frequency music exposure for 2 or 6 h twice daily, and by continuous 24-h exposure. Collectively, these findings suggest a positive modulation of cognitive and endocrine responses in adult zebrafish by environmental enrichment via the long-term exposure to music, and reinforces zebrafish as a robust, sensitive model organism for neurocognitive and neuroendocrine research.

Current State of Modeling Human Psychiatric Disorders Using Zebrafish.

Psychiatric disorders are highly prevalent brain pathologies that represent an urgent, unmet biomedical problem. Since reliable clinical diagnoses are essential for the treatment of psychiatric disorders, their animal models with robust, relevant behavioral and physiological endpoints become necessary. Zebrafish (Danio rerio) display well-defined, complex behaviors in major neurobehavioral domains which are evolutionarily conserved and strikingly parallel to those seen in rodents and humans. Although zebrafish are increasingly often used to model psychiatric disorders, there are also multiple challenges with such models as well. The field may therefore benefit from a balanced, disease-oriented discussion that considers the clinical prevalence, the pathological complexity, and societal importance of the disorders in question, and the extent of its detalization in zebrafish central nervous system (CNS) studies. Here, we critically discuss the use of zebrafish for modeling human psychiatric disorders in general, and highlight the topics for further in-depth consideration, in order to foster and (re)focus translational biological neuroscience research utilizing zebrafish. Recent developments in molecular biology research utilizing this model species have also been summarized here, collectively calling for a wider use of zebrafish in translational CNS disease modeling.

Non-Dose-Dependent Relationship between Antipredator Behavior and Conspecific Alarm Substance in Zebrafish

A series of behavioral detection paradigms have been developed for zebrafish (Danio rerio) to examine anxiety-like behavioral responses. Among them, the novel tank diving test is rapidly gaining popularity in translational neuroscience and behavioral research for the investigation of psychopharmacological activity focusing on stress. Zebrafish respond to conspecific epidermal-released alarm substances with antipredator reactions. Although the alarm responses of zebrafish were well characterized in a novel tank diving experiment, the relationship between the intensity of the alarm behavior and the concentration of the alarm substance needed to be understood more adequately. In the current paper, we investigated the behavioral phenotypes and potencies of zebrafish elicited by the serial dilution of an alarm substance in the novel tank diving test. Using a video-tracking assisted behavioral quantification approach, we demonstrated no linear concentration-dependent relationship between antipredator behavior and skin extracts, suggesting that an optimal concentration induced each typical behavioral response. The results showed that the freezing duration (%) significantly increased when stimulated with 104-fold times dilutions of skin extract (equivalent 5 × 10−5 fish/L), while erratic movements (%), time in the bottom half (%), and latency to the upper half (s) significantly elevated when stimulated with 103-fold times dilutions (equivalent 5 × 10−4 fish/L). Therefore, the concentration threshold for an alarm substance that elicited innate fear behavior in zebrafish was presumed to be an equivalent concentration of approximately 5 × 10−4 fish/L. The conclusions may fill a knowledge gap between the innate fear response triggered by injured skin and a novel tank diving paradigm that provides insights into the characterization of alarm substance, behavioral responses, and physiological response mechanisms in zebrafish.

Collaboration and knowledge integration for successful brain therapeutics – lessons learned from the pandemic

Brain diseases are a major cause of death and disability worldwide and contribute significantly to years of potential life lost. Although there have been considerable advances in biological mechanisms associated with brain disorders as well as drug discovery paradigms in recent years, these have not been sufficiently translated into effective treatments. This Special Article expands on Keystone Symposia's pre- and post-pandemic panel discussions on translational neuroscience research. In the article, we discuss how lessons learned from the COVID-19 pandemic can catalyze critical progress in translational research, with efficient collaboration bridging the gap between basic discovery and clinical application. To achieve this, we must place patients at the center of the research paradigm. Furthermore, we need commitment from all collaborators to jointly mitigate the risk associated with the research process. This will require support from investors, the public sector and pharmaceutical companies to translate disease mechanisms into world-class drugs. We also discuss the role of scientific publishing in supporting these models of open innovation. Open science journals can now function as hubs to accelerate progress from discovery to treatments, in neuroscience in particular, making this process less tortuous by bringing scientists together and enabling them to exchange data, tools and knowledge effectively. As stakeholders from a broad range of scientific professions, we feel an urgency to advance brain disease therapies and encourage readers to work together in tackling this challenge.

Degenerative cervical myelopathy and alterations in functional cerebral connectivity.

Degenerative cervical myelopathy and alterations in functional cerebral connectivity.

Mapping sheep to human brain: The need for a sheep brain atlas.

A brain atlas is essential for understanding the anatomical relationship between neuroanatomical structures. Standard stereotaxic coordinates and reference systems have been developed for humans, non-human primates and small laboratory animals to contribute to translational neuroscience research. Despite similar neuroanatomical and neurofunctional features between the sheep and human brain, little is known of the sheep brain stereotaxy, and a detailed sheep atlas is scarce. Here, we briefly discuss the value of using sheep in neurological research and the paucity of literature concerning the coordinates system during neurosurgical approaches. Recent advancements such as computerized tomography, positron emission tomography, magnetic resonance imaging, functional magnetic resonance imaging and diffusion tensor imaging are used for targeting and localizing the coordinates and brain areas in humans. Still, their application in sheep is rare due to the lack of a 3D stereotaxic sheep atlas by which to map sheep brain structures to its human counterparts. More recently, a T1- and T2-weighted high-resolution MRI 3D stereotaxic atlas of the sheep brain has been generated, however, the journey to create a sheep brain atlas by which to map directly to the human brain is still uncharted. Therefore, developing a detailed sheep brain atlas is valuable for the future to facilitate the use of sheep as a large animal experimental non-primate model for translational neurological research.

Exploring CNS Effects of American Traditional Medicines using Zebrafish Models.

Although American traditional medicine (ATM) has been practiced for millennia, its complex multi-target mechanisms of therapeutic action remain poorly understood. Animal models are widely used to elucidate the therapeutic effects of various ATMs, including their modulation of brain and behavior. Complementing rodent models, the zebrafish (Danio rerio) is a promising novel organism in translational neuroscience and neuropharmacology research. Here, we emphasize the growing value of zebrafish for testing neurotropic effects of ATMs and outline future directions of research in this field. We also demonstrate the developing utility of zebrafish as complementary models for probing CNS mechanisms of ATM action and their potential to treat brain disorders.

Carbon-Based Fiber Materials as Implantable Depth Neural Electrodes.

Implantable brain electrophysiology electrodes are valuable tools in both fundamental and applied neuroscience due to their ability to record neural activity with high spatiotemporal resolution from shallow and deep brain regions. Their use has been hindered, however, by the challenges in achieving chronically stable operations. Furthermore, implantable depth neural electrodes can only carry out limited data sampling within predefined anatomical regions, making it challenging to perform large-area brain mapping. Minimizing inflammatory responses and associated gliosis formation, and improving the durability and stability of the electrode insulation layers are critical to achieve long-term stable neural recording and stimulation. Combining electrophysiological measurements with simultaneous whole-brain imaging techniques, such as magnetic resonance imaging (MRI), provides a useful solution to alleviate the challenge in scalability of implantable depth electrodes. In recent years, various carbon-based materials have been used to fabricate flexible neural depth electrodes with reduced inflammatory responses and MRI-compatible electrodes, which allows structural and functional MRI mapping of the whole brain without obstructing any brain regions around the electrodes. Here, we conducted a systematic comparative evaluation on the electrochemical properties, mechanical properties, and MRI compatibility of different kinds of carbon-based fiber materials, including carbon nanotube fibers, graphene fibers, and carbon fibers. We also developed a strategy to improve the stability of the electrode insulation without sacrificing the flexibility of the implantable depth electrodes by sandwiching an inorganic barrier layer inside the polymer insulation film. These studies provide us with important insights into choosing the most suitable materials for next-generation implantable depth electrodes with unique capabilities for applications in both fundamental and translational neuroscience research.

Using bibliometrics to evaluate outcomes and influence of translational biomedical research centers.

Federal grant funding to support infrastructure development of translational biomedical research centers is a form of public health intervention. Establishing rigorous methods for measuring center success and outcomes is essential to justify continued funding. Bibliometric data compiled from a 5-year funding cycle of neurodegeneration and translational neuroscience research center were analyzed using the package bibliometrix for open-source software R and the NIH-developed research tool iCite. The research team and their collaborators (n = 485) produced 157 grant-citing publications from 2015-2020. The science was produced by small research teams clustered around three main communities of topics: Alzheimer's Disease, brain imaging, and neuropsychological testing in the elderly. Using the relative citation ratio, the publications produced by the research team were found to be influential when compared to other R01-funded publications. Recent developments in bibliometric analysis expand beyond traditional measurement capabilities to better understand the characteristics, outcomes, and influences of research teams. These findings can be used to inform researchers and institutions about research team composition, productivity, and success. Measures of research influence may be used to justify return on investment to funders.

Ethical dimensions of translational developmental neuroscience research in autism.

BackgroundSince the 1990s, increasing research has been devoted to the identification of biomarkers for autism to help attain more objective diagnosis; enable early prediction of prognosis; and guide individualised intervention options. Early studies focused on the identification of genetic variants associated with autism, but more recently, research has expanded to investigate neurodevelopmental markers. While ethicists have extensively discussed issues around advances in autism genomics, much less ethical scrutiny has focused on research on early neurodevelopment and on the interventions being developed as a result.ObjectivesWe summarise the current state of the science on the identification of early markers for autism and its potential clinical applications, before providing an overview of the ethical issues arising from increasing understanding of children’s neurodevelopment in very early life.ResultsAdvances in the understanding of brain and behavioural trajectories preceding later autism diagnosis raise ethical concerns around three themes: (1) New models for understanding autism; (2) Risks and benefits of early identification and intervention; and (3) Communication of early concerns to families. These ethical issues should be further investigated in research conducted in partnership with autistic people and their families.ConclusionsThis paper highlights the need for ethical scrutiny of early neurodevelopmental research in autism. Scrutiny requires expertise and methods from the basic sciences and bioethics, as well as constructive collaborations among autistic people, their parents, and autism researchers to anticipate early interventions that serve the community’s interests and accommodate the varied experiences and preferences of people on the spectrum and their families.