Human Brain Disorders Research Articles

The Emergence of Stem Cell-Based Brain Organoids: Trends and Challenges.

Recent developments in 3D cultures exploiting the self-organization ability of pluripotent stem cells have enabled the generation of powerful in vitro systems termed brain organoids. These 3D tissues recapitulate many aspects of human brain development and disorders occurring in vivo. When combined with improved differentiation methods, these in vitro systems allow the generation of more complex "assembloids," which are able to reveal cell diversities, microcircuits, and cell-cell interactions within their 3D organization. Here, the ways in which human brain organoids have contributed to demystifying the complexities of brain development and modeling of developmental disorders is reviewed and discussed. Furthermore, challenging questions that are yet to be addressed by emerging brain organoid research are discussed.

Pig Brains Have Homologous Resting-State Networks with Human Brains.

Many neurological and psychiatric diseases in humans are caused by disruptions to large-scale functional properties of the brain, including functional connectivity. There has been growing interest in discovering the functional organization of brain networks in larger animal models. As a result, the use of translational pig models in neuroscience has significantly increased in the past decades. The gyrencephalic pig brain resembles the human brain more in anatomy, growth, and development than the brains of commonly used small laboratory animals such as rodents. In this work, resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) data were acquired from a group of pigs (n = 12). rs-fMRI data were analyzed for resting-state networks (RSNs) by using independent component analysis and sparse dictionary learning. Six RSNs (executive control, cerebellar, sensorimotor, visual, auditory, and default mode) were detected that resemble their counterparts in human brains, as measured by Pearson spatial correlations and mean ratios. Supporting evidence of the validity of these RSNs was provided through the evaluation and quantification of structural connectivity measures (mean diffusivity, fractional anisotropy, fiber length, and fiber density) estimated from the DTI data. This study shows that as a translational, large animal model, pigs demonstrate great potential for mapping connectome-scale functional connectivity in experimental modeling of human brain disorders.

Quantitative Rodent Brain Receptor Imaging

Positron emission tomography (PET) is a non-invasive imaging technology employed to describe metabolic, physiological, and biochemical processes in vivo. These include receptor availability, metabolic changes, neurotransmitter release, and alterations of gene expression in the brain. Since the introduction of dedicated small-animal PET systems along with the development of many novel PET imaging probes, the number of PET studies using rats and mice in basic biomedical research tremendously increased over the last decade. This article reviews challenges and advances of quantitative rodent brain imaging to make the readers aware of its physical limitations, as well as to inspire them for its potential applications in preclinical research. In the first section, we briefly discuss the limitations of small-animal PET systems in terms of spatial resolution and sensitivity and point to possible improvements in detector development. In addition, different acquisition and post-processing methods used in rodent PET studies are summarized. We further discuss factors influencing the test-retest variability in small-animal PET studies, e.g., different receptor quantification methodologies which have been mainly translated from human to rodent receptor studies to determine the binding potential and changes of receptor availability and radioligand affinity. We further review different kinetic modeling approaches to obtain quantitative binding data in rodents and PET studies focusing on the quantification of endogenous neurotransmitter release using pharmacological interventions. While several studies have focused on the dopamine system due to the availability of several PET tracers which are sensitive to dopamine release, other neurotransmitter systems have become more and more into focus and are described in this review, as well. We further provide an overview of latest genome engineering technologies, including the CRISPR/Cas9 and DREADD systems that may advance our understanding of brain disorders and function and how imaging has been successfully applied to animal models of human brain disorders. Finally, we review the strengths and opportunities of simultaneous PET/magnetic resonance imaging systems to study drug-receptor interactions and challenges for the translation of PET results from bench to bedside.

Multivariate graph learning for detecting aberrant connectivity of dynamic brain networks in autism.

Alterations in static functional brain networks have previously been reported in Autistic Spectrum Disorder (ASD). Although functional brain networks are known to be time-varying, alterations in time-varying or dynamic brain networks in ASD is largely unknown. Hence, in this study, we analyze resting-state fMRI data of ASD group versus Typically Developing Control (TDC) group to understand alterations in dynamic functional brain networks in ASD vis-à-vis healthy controls. We introduce a new framework for extracting overlapping dynamic functional brain networks to study these alterations. We utilize sliding window approach along with the recent Multivariate Vector Regression-based Connectivity (MVRC) method to construct functional connectivity (FC) matrices in each time-window. Further, we build three-mode subject-summarized spatio-temporal tensor in both ASD and TDC groups. This tensor is utilized to determine a set of overlapping dynamic functional brain networks and their temporal profiles. This helps us in studying alterations in dynamic brain networks in ASD subjects at the group-level. The proposed framework is tested on two publicly available resting-state fMRI dataset of ASD and normal controls. Our analyses on resting-state fMRI data indicate that dynamic functional brain networks of ASD subjects are altered compared to the TDC group. Two-sample t-test is used to establish the statistical significance of the differences observed in network strengths of the two groups. Compared to the TDC subjects, autistic subjects showed alterations in multiple functional brain networks including cognitive control, subcortical, auditory, visual, bilateral limbic, and default mode network. The proposed methodology is able to provide information on alterations in dynamic functional brain networks in ASD and may provide potential biomarkers for studying human brain disorders.

A cross-disorder connectome landscape of brain dysconnectivity.

Many human brain disorders are associated with characteristic alterations in the structural and functional connectivity of the brain. In this article, we explore how commonalities and differences in connectome alterations can reveal relationships across disorders. We survey recent literature on connectivity changes in neurological and psychiatric disorders in the context of key organizational principles of the human connectome and observe that several disturbances to network properties of the human brain have a common role in a wide range of brain disorders and point towards potentially shared network mechanisms underpinning disorders. We hypothesize that the distinct dimensions along which connectome networks are organized (for example, 'modularity' and 'integration') provide a general coordinate system that allows description and categorization of relationships between seemingly disparate disorders. We outline a cross-disorder 'connectome landscape of dysconnectivity' along these principal dimensions of network organization that may place shared connectome alterations between brain disorders in a common framework.

Using brain organoids to study human neurodevelopment, evolution and disease.

The brain is one of the most complex organs, responsible for the advanced intellectual and cognitive ability of humans. Although primates are to some extent capable of performing cognitive tasks, their abilities are less evolved. One of the reasons for this is the vast differences in the brain of humans compared to other mammals, in terms of shape, size and complexity. Such differences make the study of human brain development fascinating. Interestingly, the cerebral cortex is by far the most complex brain region resulting from its selective evolution within mammals over millions of years. Unraveling the molecular and cellular mechanisms regulating brain development, as well as the evolutionary differences seen across species and the need to understand human brain disorders, are some of the reasons why scientists are interested in improving their current knowledge on human corticogenesis. Toward this end, several animal models including primates have been used, however, these models are limited in their extent to recapitulate human-specific features. Recent technological achievements in the field of stem cell research, which have enabled the generation of human models of corticogenesis, called brain or cerebral organoids, are of great importance. This review focuses on the main cellular and molecular features of human corticogenesis and the use of brain organoids to study it. We will discuss the key differences between cortical development in human and nonhuman mammals, the technological applications of brain organoids and the different aspects of cortical development in normal and pathological conditions, which can be modeled using brain organoids. This article is categorized under: Comparative Development and Evolution > Regulation of Organ Diversity Nervous System Development > Vertebrates: General Principles.

The Body Size of Stimulus Conspecifics Affects Social Preference in a Binary Choice Task in Wild-Type, But Not in dyrk1aa Mutant, Zebrafish.

The zebrafish has become an appropriate animal model in the analysis of numerous human brain disorders. A variety of neuropsychiatric conditions and neurodevelopmental disorders are comorbid with abnormal social behavior. Given the translational relevance of zebrafish, multidisciplinary studies employing behavioral, neurobiological, and molecular methods with this species may provide insights into human central nervous system (CNS) disorders. Many of these studies impinge upon our ability to properly induce and quantify the behavior of zebrafish, a relatively understudied aspect of this species. In this study, we investigate how the body size of conspecifics relative to that of the test subject influences social (shoaling) responses in zebrafish. We found a robust preference by wild-type (WT) test zebrafish toward big conspecifics, but not toward smaller conspecifics. Additionally, we tested an autism-relevant zebrafish knockout (KO) model. The dyrk1aa KO zebrafish showed impaired social preference compared with WT in the social behavior test. Our results confirm the effect of relative body size on social preference and that the social preference task developed for zebrafish may uncover the function of genes and biological mechanisms potentially associated with human CNS disorders.

Brain organoids: advances, applications and challenges.

Brain organoids are self-assembled three-dimensional aggregates generated from pluripotent stem cells with cell types and cytoarchitectures that resemble the embryonic human brain. As such, they have emerged as novel model systems that can be used to investigate human brain development and disorders. Although brain organoids mimic many key features of early human brain development at molecular, cellular, structural and functional levels, some aspects of brain development, such as the formation of distinct cortical neuronal layers, gyrification, and the establishment of complex neuronal circuitry, are not fully recapitulated. Here, we summarize recent advances in the development of brain organoid methodologies and discuss their applications in disease modeling. In addition, we compare current organoid systems to the embryonic human brain, highlighting features that currently can and cannot be recapitulated, and discuss perspectives for advancing current brain organoid technologies to expand their applications.

A New Family of Imidazoline I2 Receptor Ligands Improves Behavior and Cognition in SAMP8 Mice

Imidazoline I2 receptors (I2‐IR) are widely distributed in the central nervous system. I2‐IR are associated with human brain disorders and I2‐IR proteins are increased in the patients that suffered from Alzheimer's disease (AD). Since structural data for I2‐IR remains unknown, the discovery of selective I2‐IR ligands devoid of alfa2‐adrenoceptor affinity is likely to provide valuable tools to define the pharmacological characterization of these receptors.We reported a new family of (2‐imidazoline‐4‐yl)phosphonates that showed, in radioligand binding studies, higher affinity and selectivity for I2‐IR than idazoxan and other standard I2‐IR ligands. New compounds exhibit good blood‐brain‐barrier properties (PAMPA assay). In vivo studies in mice showed that acute treatments with two of the new ligands induces hypothermia, significantly increases p‐FADD/FADD ratio, an index of cell survival, and reduced hippocampal p35 cleavage into neurotoxic p25, indicating a neuroprotective role.Herein, we present the cognitive and molecular analysis of the treatment of female senescence accelerated mouse‐prone 8 mice (SAMP8) with two leads of our new family of I2‐IR ligands. In particular, 12 months‐old SAMP8 (n=26) were divided randomly into three groups (control, n=10), SAMP8 treated with I2‐IR ligands (compound 1, n= 8 and compound 2, n= 8). Compounds were administered through drinking water and concentration dose adjusted to reach a 5 mg/kg/day during 4 weeks. Behavior and cognitive effects were investigated through three well‐established tests, OFT, EPM and NORT, showing beneficial effects on treated animals. These results were supported by the assessment of key molecular markers for oxidative stress, inflammation indicators, synapsis and apoptosis, parameters related with cognitive decline and AD.Further, in vitro selectivity and ADME‐TOX profiling (human and mice microsomal stability, cytotoxicity, cytochromes inhibition, Caco‐2 permeability, hERG inhibition) and pharmacokinetics will be presented for a lead candidate.In summary, here we present the effectiveness of two new I2‐IR ligands in an in vivo model (SAMP8) for cognitive decline. Although different authors reported the relationship between I2‐ IR and cognitive decline, this study is the first experimental evidence that propose I2‐IR as a new therapeutic target to face AD, an unmet medical need.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

An aggregation-prone mutant of eIF3a forms reversible assemblies escaping spatial control in exponentially growing yeast cells

Cells have elaborated a complex strategy to maintain protein homeostasis under physiological as well as stress conditions with the aim to ensure the smooth functioning of vital processes and producing healthy offspring. Impairment of one of the most important processes in living cells, translation, might have serious consequences including various brain disorders in humans. Here, we describe a variant of the translation initiation factor eIF3a, Rpg1-3, mutated in its PCI domain that displays an attenuated translation efficiency and formation of reversible assemblies at physiological growth conditions. Rpg1-3-GFP assemblies are not sequestered within mother cells only as usual for misfolded-protein aggregates and are freely transmitted from the mother cell into the bud although they are of non-amyloid nature. Their bud-directed transmission and the active movement within the cell area depend on the intact actin cytoskeleton and the related molecular motor Myo2. Mutations in the Rpg1-3 protein render not only eIF3a but, more importantly, also the eIF3 core complex prone to aggregation that is potentiated by the limited availability of Hsp70 and Hsp40 chaperones. Our results open the way to understand mechanisms yeast cells employ to cope with malfunction and aggregation of essential proteins and their complexes.

The potential role of magnetic resonance brain relaxometry in veterinary medicine: a preliminary study.

Magnetic Resonance (MR) is a non-invasive modality of choice for the evaluation of brain morphology, with superior performance as compared to other techniques. However, MR images are typically assessed qualitatively, thus relying on the experience of the involved radiologist. This may lead to errors of interpretation in the presence of subtle alterations and does not exploit the full potential of this technique as a quantitative diagnostic tool. To this end Magnetic Resonance Relaxometry (MRR), which is able to quantitively characterize the tissues under investigation through their relaxation rates, seems extremely promising. Many studies assessed the feasibility of relaxometry as a diagnostic tool in human brain disorders, with the most promising results obtained in the evaluation of neurodegenerative diseases and in the oncologic field. However, despite such extensive literature in human medicine, due to the lack of standardized protocols and the need of high-field MRI scanners, to date few studies have been performed on companion animals. In this work, first we describe relaxometry applications in human neuropathology and their possible extension to companion animals both in the experimental and clinical fields. Then, we present two experiments performed on a typical standard clinical scanner operating at 0.25 T to show that, despite the low field intensity, this technique may be promising even in the clinical setup. We tested the relaxometry protocol in a phantom study and then applied it to a real clinical case study. The results showed that this protocol used on a phantom led to a higher contrast, as compared to the standard approach. Furthermore, when applied to a real case study, this protocol revealed brain lesions undetected by the standard technique which were confirmed by a histopathological examination. These preliminary results are encouraging and support the development of this approach as an advanced diagnostic tool even in a clinical setting where low field MRI scanners are typically employed.

Neuroethical Issues of the Brain/MINDS Project of Japan

The Brain/MINDS project aims to further understand the human brain and neuropsychiatric disorders through "translatable" biomarkers. Here, we describe the neuroethical issues of the project that have arisen from clinical data collection and the use of biological models of neuropsychiatric disorders.

29 - CHARACTERIZATION OF CROSS-TISSUE mQTL EFFECTS AND THEIR RELEVANCE IN PSYCHIATRIC DISORDERS

Background Epigenetics has been known to mediate genetic risks and regulate gene expression in complex diseases. Due to substantial epigenetic variation, particularly DNA methylation, is tissue specific, sample accessibility has been one of the major road blockers in epigenetic research for human brain disorders. However, previous studies have shown that DNA methylation can also be significantly regulated by genetics and such effect is relatively consistent cross tissues. A better understanding of this genetic and epigenetic relationship can be very beneficial for the investigation of diseases pathology. In this work, we conducted a comprehensive analysis of genetic influence on DNA methylation across brain and peripheral tissues, characterized genetics and their target CpGs, and their functional relevance to psychiatric diseases. Methods We performed a genome-wide methylation quantitative trait loci (meQTLs) analysis on postmortem brain prefrontal cortex, whole blood and saliva. Cis-acting SNP-methylation pairs (distance Results We found significant overlap of meQTLs and targeted CpGs cross tissue (34%-73%). MeQTLs in blood showed the strongest cis-effect followed by brain and saliva regardless of direction of effect. Cross-tissue meQTL targeted CpGs were highly distributed on CpG island shore regions (OR: odds ratio = 1.3, P = 2.8e-99) and had a much higher probability being blood brain correspondent than non-meQTL target CpGs (OR=6.6). Cross-tissue meQTLs showed significant enrichment in risk loci of five major psychiatric disorders (OR: odds ratio = [1.65 - 5.42]). In addition, these cross-tissue meQTLs also enriched significantly in cross-tissue eQTLs (OR = 16.21), where 351 SNPs were meQTl, eQTL, and carried significant schizophrenia risk, mainly from regions 6p21.1 – 6p24.3. Finally, we found more similar co-methylation network structure between brain and blood than brain and saliva, and identified one consensus module showing significant schizophrenia risk (Z= -4.54, p = 5.5e-6). Discussion Results show strong cross-tissue similarity of meQTLeffects, especially between brain and blood, and their significant enrichment in psychiatric disorders, supporting the surrogate role of peripheral tissues in studying pathology of genetic effect on brain disorders through methylation.

Animal models of depression: pros and cons.

Animal models of depression are certainly needed but the question in the title has been raised owing to the controversies in the interpretation of the readout in a number of tests, to the perceived lack of progress in the development of novel treatments and to the expressed doubts in whether animal models can offer anything to make a true breakthrough in understanding the neurobiology of depression and producing novel drugs against depression. Herewith, it is argued that if anything is wrong with animal models, including those for depression, it is not about the principle of modelling complex human disorder in animals but in the way the tests are selected, conducted and interpreted. Further progress in the study of depression and in developing new treatments, will be supported by animal models of depression if these were more critically targeted to drug screening vs. studies of underlying neurobiology, clearly stratified to vulnerability and pathogenetic models, focused on well-defined endophenotypes and validated for each setting while bearing the existing limits to validation in mind. Animal models of depression need not to rely merely on behavioural readouts but increasingly incorporate neurobiological measures as the understanding of depression as human brain disorder advances. Further developments would be fostered by cross-fertilizinga translational approach that is bidirectional, research on humans making more use of neurobiological findings in animals.

Alterations of Expression of the Serotonin 5-HT4 Receptor in Brain Disorders.

The serotonin 4 receptor, 5-HT4R, represents one of seven different serotonin receptor families and is implicated in a variety of physiological functions and their pathophysiological variants, such as mood and depression or anxiety, food intake and obesity or anorexia, or memory and memory loss in Alzheimer’s disease. Its central nervous system expression pattern in the forebrain, in particular in caudate putamen, the hippocampus and to lesser extent in the cortex, predispose it for a role in executive function and reward-related actions. In rodents, regional overexpression or knockdown in the prefrontal cortex or the nucleus accumbens of 5-HT4R was shown to impact mood and depression-like phenotypes, food intake and hypophagia; however, whether expression changes are causally involved in the etiology of such disorders is not clear. In this context, more data are emerging, especially based on PET technology and the use of ligand tracers that demonstrate altered 5-HT4R expression in brain disorders in humans, confirming data stemming from post-mortem tissue and preclinical animal models. In this review, we would like to present the current knowledge of 5-HT4R expression in brain regions relevant to mood/depression, reward and executive function with a focus on 5-HT4R expression changes in brain disorders or caused by drug treatment, at both the transcript and protein levels.

Long-term behavioural effects of maternal obesity in C57BL/6J mice

Diet is increasingly being recognised as an important contributor to mental health. A diet high in sugar and polyunsaturated fatty acids can have negative consequences for disease symptoms and outcomes in schizophrenia patients. There is also evidence that particular diets can have beneficial, therapeutic-like properties for human brain disorders. Additionally, dietary choices of mothers have been found to affect cognitive domains and anxiety behaviour of offspring. Here we investigated the effects of maternal high fat diet (HFD) on a variety of behavioural domains in offspring and also consider behaviours, which are schizophrenia-relevant. Female C57BL/6 J mice were fed HFD (N = 13) or chow (N = 11) from 6 weeks prior to mating, during gestation and lactation. The male offspring of these mothers were weaned onto chow on PND24 and underwent testing for a range of behavioural outcomes starting at 38 weeks of age. Offspring of HFD mothers were significantly heavier compared to those of control mothers from weaning and throughout the duration of the experiment. Offspring of HFD mothers had significantly improved sensorimotor gating compared to offspring of control mothers but showed no altered behavioural response in tests for cognition, sociability, locomotion or exploration. Future investigations are required to assess which HFD-induced factors are responsible for the effects, e.g. altered maternal nursing behaviour, altered gestational physiology, or others warrants further investigation.

Differential Effects of Heparin and Hyaluronic Acid on Neural Patterning of Human Induced Pluripotent Stem Cells.

A lack of well-established animal models that can efficiently represent human brain pathology has led to the development of human induced pluripotent stem cell (hiPSC)-derived brain tissues. Brain organoids have enhanced our ability to understand the developing human brain and brain disorders (e.g., Schizophrenia, microcephaly), but the organoids still do not accurately recapitulate the anatomical organization of the human brain. Therefore, it is important to evaluate and optimize induction and signaling factors in order to engineer the next generation of brain organoids. In this study, the impact of hyaluronic acid (HA), a major brain extracellular matrix (ECM) component that interacts with cells through ligand-binding receptors, on the patterning of brain organoids from hiPSCs was evaluated. To mediate HA- binding capacity of signaling molecules, heparin was added in addition to HA or conjugated to HA to form hydrogels (with two different moduli). The neural cortical spheroids derived from hiPSCs were treated with either HA or heparin plus HA (Hep- HA) and were analyzed for ECM impacts on neural patterning. The results indicate that Hep-HA has a caudalizing effect on hiPSC-derived neural spheroids, in particular for stiff Hep-HA hydrogels. Wnt and Hippo/Yes-associated protein (YAP) signaling was modulated (using Wnt inhibitor IWP4 or actin disruption agent Cytochalasin D respectively) to understand the underlying mechanism. IWP4 and cytochalasin D promote forebrain identity. The results from this study should enhance the understanding of influence of biomimetic ECM factors for brain organoid generation.

Bridging the species gap in translational research for neurodevelopmental disorders.

The prevalence and societal impact of neurodevelopmental disorders (NDDs) continue to increase despite years of research in both patient populations and animal models. There remains an urgent need for translational efforts between clinical and preclinical research to (i) identify and evaluate putative causes of NDD, (ii) determine their underlying neurobiological mechanisms, (iii) develop and test novel therapeutic approaches, and (iv) translate basic research into safe and effective clinical practices. Given the complexity behind potential causes and behaviors affected by NDDs, modeling these uniquely human brain disorders in animals will require that we capitalize on unique advantages of a diverse array of species. While much NDD research has been conducted in more traditional animal models such as the mouse, ultimately, we may benefit from creating animal models with species that have a more sophisticated social behavior repertoire such as the rat (Rattus norvegicus) or species that more closely related to humans, such as the rhesus macaque (Macaca mulatta). Here, we highlight the rat and rhesus macaque models for their role in previous psychological research discoveries, current efforts to understand the neurobiology of NDDs, and focus on the convergence of behavior outcome measures that parallel features of human NDDs.

FAK family kinases in brain health and disease

Brain disorders are now identified as one of the largest and costliest health risks throughout human life. While most brain disorders are not life threatening per se, their chronic and incurable nature renders the overall burden from these disorders much greater than would be suggested by mortality figures alone. Several neurodevelopmental conditions, including autism and dyslexia, are being diagnosed at increasing rates throughout the last few decades. Adolescence is now well recognized as a vulnerable brain developmental phase, in which mental disorders such as schizophrenia, depression, and bipolar disorder first appear. Additionally, the constant increase in life expectancy has led to a significant rise in the risk of several neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD). A primary research goal of neuroscience is to decipher the molecular mechanisms that play direct roles in the pathophysiology of brain disorders, including those of the young and old alike. Research into these mechanisms will have the most significant impact on brain diseases and mental health. The focal adhesion kinase (FAK) and its homologous FAK-related proline-rich tyrosine kinase 2 (Pyk2) define a distinct family of non-receptor tyrosine kinases that are predominantly expressed in the developing as well as in the adult brain. Despite their high similarity, they are believed to fulfill distinct roles within the brain, which are partially determined by their different expression patterns, localization, and interacting proteins. Here, we provide a comprehensive and up-to-date overview of all known neuronal interactors and signaling pathways in which Pyk2 and FAK are involved. Using bioinformatics analysis and statistical tools, we validate, for the first time, the long-term hypothesis by which FAK is involved in axonal guidance and neurodevelopmental signaling, while Pyk2 has a more prominent role in functions of the adult brain, such as memory and learning. We also characterize two new and previously unidentified roles of Pyk2 in neuropathic pain signaling and neuroinflammation. Correlation of the most significant pathways for each kinase with human brain disorders revealed the involvement of Pyk2 in neurodegenerative diseases such as PD, AD, Huntington's disease (HD), and schizophrenia, while FAK was found to be mostly related to neurodevelopmental disorders in which axonal guidance plays a major role, and to a lesser extent to amyotrophic lateral sclerosis (ALS), schizophrenia, mood disorders, and AD. The involvement of FAK in these non-developmental pathways may suggest its possible role in compensating for Pyk2 in specific processes and/or brain disorders. Understanding the molecular mechanisms underlying regulation of FAK family proteins in brain and behavior may lead to novel therapeutic approaches for preventing or treating the underlying causes of neurodevelopmental abnormalities, psychiatric disorders, and neurodegenerative diseases.

Extracellular Vesicles for Research on Psychiatric Disorders.

Extracellular vesicles (EVs) have gained increasing attention as underexplored intercellular communication mechanisms in basic science and as potential diagnostic tools in translational studies, particularly those related to cancers and neurological disorders. This article summarizes accumulated findings in the basic biology of EVs, EV research methodology, and the roles of EVs in brain cell function and dysfunction, as well as emerging EV studies in human brain disorders. Further research on EVs in neurobiology and psychiatry may open the door to a better understanding of intercellular communications in healthy and diseased brains, and the discovery of novel biomarkers and new therapeutic strategies in psychiatric disorders.