Alzheimer’s disease (AD) is a major type of dementia and neurodegenerative disease, characterized by memory loss and cognitive decline. Over decades, significant efforts have been dedicated to finding its cause, pathogenic mechanisms, biomarkers for early detection, and clinical trials for its treatment. Earlier approved drugs mainly ameliorated the symptoms of AD, until recent years when two drugs targeting amyloid-beta (Aβ) protein were approved to slow down the progression of the disease. This review article encompasses the history of drug development in treating AD and clinical trials that failed and succeeded. Clinicaltrials.org website was systematically searched and screened for randomized controlled trials with results posted in the past 10 years. Among the 3,388 AD clinical trials, 211 interventional studies registered under AD have met eligibility. This review includes the interventional targets for drug discovery such as Aβ, tau, neurotransmitter receptors, neuroinflammation, multi-target studies, repurposing pharmacological agents, non-pharmacological interventions, and clinical therapy development for the neuropsychiatric symptoms of dementia. Current clinical trials are ongoing and no results are available as of yet. With the vast choices of drug targets that have been investigated, this review aims to present some insights into future AD drug design and trials and contribute to our ongoing efforts to find the cure.

Brain development, a complex process, consisting of several phases, starting as early as two weeks after conception, and continuing through childhood till early adolescence, is crucial for the development of properly functioning body systems, behavioral traits, and neurocognitive abilities. Infancy and childhood are recognized as important periods for initial brain formation, however in later stages of life, such as childhood and adulthood, experiences, together with environmental exposures, can still influence brain physiology. The developing brain is particularly susceptible to epigenetic changes with many factors being proposed as modifiers by directly impacting DNA methylation as well as histone and chromatin modifications within genes implicated in development. These factors include: maternal stress and diet, exposure to pollutants, sleep quality, as well as dietary habits. Evidence indicates exposures to environmental threats can lead to inappropriate neurological, metabolic, and endocrine functioning often mediated by epigenetic mechanisms with symptoms manifesting themselves as early as childhood or in later stages of life. Therefore, the main aim of this review is to evaluate the current studies focused on negative environmental exposures and their consequences on the developing brain directed by epigenetic mechanisms.

As an integral part of human chronobiology, the circadian system plays a crucial role in regulating key biological functions, including sleep and the intricate hormonal rhythms of melatonin (MLT) and cortisol (CORT). Scholars have increasingly recognized environmental stressors as significant contributors to disturbed sleep patterns. Albeit vigorously discussed individually, the literature lacks comprehensive insights into the synergistic effect of artificial light at night (ALAN) and noise. The aim of this review is to look into the intricate interplay of the ALAN effects on sleep architecture, the modulation of circadian function, and how this influences homeostatic sleep. Furthermore, ALAN suppresses MLT secretion, which is most pronounced in response to short wavelengths of light. In addition, this review will demonstrate how exposure to noise during sleep elevates CORT and noradrenaline levels, which contributes to stress-related diseases and sleep disturbances. ALAN and noise, persistently emitted into the environment, share intrinsic mechanisms with comparable characteristics. Therefore, understanding their combined impact has become increasingly urgent. Pre-sleep exposure to both ALAN and noise acts as a potent stressor, with the potential to disrupt sleep patterns. Interestingly, during sleep, noise emerges as the predominant influence on sleep quality. Moreover, these stressors often synergize and amplify one another’s adverse effects. Thus, limiting their exposure is crucial for cultivating a sustainable environment conducive to quality sleep and overall well-being.

All living organisms exhibit circadian rhythms. Humans show circadian rhythm of the different physiological functions such as sleep-wake cycle, core body temperature, feeding behavior, metabolic activity, heart rate variability, hormone secretion, and others. The hypothalamic suprachiasmatic nucleus (SCN) acts as a primary circadian pacemaker. Peripheral tissues have an endogenous circadian clock; however, SCN synchronizes the circadian activity of the peripheral clocks. The retinohypothalamic tract (RHT) from retinal ganglionic cells carries the photic signal into the SCN that regulates the rhythmic expression of the core clock genes through the feedback loop. At the output level, the SCN connects with the pineal gland and the peripheral tissues with the help of neuroendocrine mediators. Disruption of circadian clock functions is detrimental to health. Shift work, night work, chronic or acute jet lag, and light-at-night have adverse effects on circadian functions. Misalignment of circadian rhythm alters the expression of core clock genes, leading to deregulation of cellular activity and metabolic functions. Circadian rhythm dysfunction causes many pathologic conditions, including sleep disorders, cardiovascular problems, metabolic dysfunction, infertility, poor physical performance, as well as cancer. The present work has reviewed the relationship between circadian clock dysfunction and impaired physiological activities.

Epilepsy, a prevalent neurological disorder, is characterized by chronic seizures resulting from abnormal electrical activity in the brain. Adequate medical treatment allows roughly 70% of patients to enjoy a seizure-free life. However, throughout history, epilepsy has acquired diverse interpretations due to the experienced seizures, transforming the condition from a clinical issue into a social stigma. Therefore, the aim of this review study is to review stigma and psychosocial problems in patients with epilepsy (PwE). For this reason, this study utilises sources from the last ten years and reports current data. As a result of the review, it was found that societal discrimination in PwE arises primarily from inadequate knowledge, misconceptions, and negative attitudes toward the condition. Other contributing factors were include patients’ lower levels of education and income, frequent seizures due to inadequate treatment, age at onset, duration of the disease, depressive symptoms, and lack of social support. Also, it was found that the stigma individuals with epilepsy face plays a pivotal role in exacerbating their psychosocial problems. Unfortunately, stigma and psychosocial challenges appear to be in a vicious circle, with an increase in one increasing the other. Stigmatized patients tended to isolate themselves from society, further increasing their likelihood of experiencing a depressive mood or psychiatric comorbidity. Consequently, individuals with epilepsy encounter difficulties in various domains such as marriage, work, education, and personal life. Considering these significant psychosocial burdens, it is essential to recognize that epilepsy surpasses its medical implications. Unfortunately, current efforts to reduce stigma remain insufficient, necessitating urgent and comprehensive measures to address this issue.

Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O⁶-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.

The circadian rhythm is a critical system that governs an organism’s functions in alignment with the light-dark cycle. Melatonin release from the pineal gland plays a crucial role in regulating the internal clock of the body. Multiple neurotransmitter systems in the central nervous system are linked to the release of melatonin. In this review, the relationship between circadian rhythm, melatonin secretion and various neurotransmitter systems are mainly discussed. Serotonin regulates the circadian rhythm through projections from raphe nuclei. Agomelatine is an example of the synergistic interaction between melatonin and serotonin. Melatonergic agents and selective serotonin reuptake inhibitors also exert notable impacts on depression in concomitant use. Dopamine has an inhibitory effect on melatonin release, while melatonin also inhibits dopamine release. This should be taken into account when considering the use of melatonin in Parkinson’s disease. On the contrary, use of melatonin may offer therapeutic advantages for schizophrenia and tardive dyskinesia. The interaction between norepinephrine and melatonin exhibits diurnal variability, with norepinephrine promoting arousal and inhibiting daytime melatonin secretion. Melatonergic neurons also exert a specific protective influence on cholinergic neurons. Interaction between the histaminergic and melatonergic systems is significant, particularly in association with immunity, sleep, and circadian rhythm. Novel ligands with dual-acting properties, interacting with both the histaminergic and melatonergic systems are investigated. Currently, there is a limited number of approved melatonergic agents that primarily demonstrate positive effects in addressing insomnia and depression. However, there is considerable potential in studying new agents that target both the melatonergic and other neurotransmitter systems, which alleviate various conditions, including neurodegenerative diseases, dementia, autoimmune diseases, allergic diseases, epilepsy, and other neuropsychiatric disorders. The ongoing process of developing and evaluating new ligands selectively targeting the melatonergic system remains crucial in understanding the complex relationship between these systems.

Exposure to stressful conditions plays a critical role in brain processes, including neural plasticity, synaptic transmission, and cognitive functions. Since memory-related brain regions, the hippocampus (Hip), the amygdala, and the prefrontal cortex, express high glucocorticoid receptors (GRs), these areas are the potential targets of stress hormones. Stress affects memory encoding, consolidation, and retrieval, which may depend on many factors such as the type, duration, the intensity of the stressor or the brain region. Here, this review mainly focused on the mechanisms involved in stress-induced memory impairment. Acute/chronic stress induces structural and functional changes in neurons and glial cells. Dendritic arborization, reduction of dendritic spine density, and alteration in glutamatergic-mediated synaptic transmission via N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are mechanisms that stress affect long-term memory formation. Exposure to acute or chronic stress could interplay with multiple neurotransmitter signaling, modulating the neuronal circuits involved in memory impairment or state-dependent learning. Stress hormones also modulate the expression of microRNAs in the specific brain regions responsible for stress-induced behaviors. Because of expressing GRs in astrocytes and microglial cells, stress could affect the morphology, structure, and functions of these glial cells in memory-related brain regions. Astrocytes play a crucial role in stress-induced aversive or fear memory formation. Over-activation of the microglial cells enhances the release of inflammatory cytokines, which results in neuronal injury. Stress has a prominent role in cognitive decline to induces memory problems, particularly in older adults. Due to the issue’s importance, here the provided overview attempted to address the question of how stress alters neuronal epigenetic regulators, synaptic transmissions, and glial activity in the brain.

Neural disorders refer to conditions of the nervous system due to infection or degeneration of the neurons leading to either neurodegenerative disorder or neuropsychiatric disorder. Some such disorders of the nervous system include Parkinsons’s disease, depression, amnesia, dementia, Alzheimer’s disease, schizophrenia, cerebrovascular impairment, epilepsy, seizure disorders, etc. In conventional medical system, some medicines belonging to the class of psychodelic drugs, sedatives, neurotransmitters, neuro-stimulants, etc. are in extensive use. Unfortunately, most of these drugs either delay the progression of the neural disorder or leave the patient with prominent adverse side effects. Several potent bioactive compounds with neuroprotective potential have been reported from medicinal plants and some of them have been found to be highly effective. Belonging from natural sources, mostly, the plant derived compounds exhibit minimum or no cytotoxicity at a prescribed standardised dose against a particular health ailment. Many such phytocompounds from plant sources with potent neuroprotective activities have been in use in Ayurvedacharya, Unani, and Chinese medicine for ages. The compounds if isolated chemically, modified to make more potent neuroprotective derivatives and utilised to make highly effective neuroprotective pharmaceutical formulations with minimum side effects, may open new revolutionary doorways in neuropharmacology. In this review, it has been briefly discussed about the neuroprotective compounds isolated from certain indigenous plants of West Bengal, India, and their mechanism of action.

The SAR-CoV-2 virus has evolved to co-exist with human hosts, albeit at a substantial energetic cost resulting in post-infection neurological manifestations [Neuro-post-acute sequelae of SARS-CoV-2 infection (PASC)] that significantly impact public health and economic productivity on a global scale. One of the main molecular mechanisms responsible for the development of Neuro-PASC, in individuals of all ages, is the formation and inadequate proteolysis/clearance of phase-separated amyloid crystalline aggregates—a hallmark feature of aging-related neurodegenerative disorders. Amyloidogenesis during viral infection and persistence is a natural, inevitable, protective defense response that is exacerbated by SARS-CoV-2. Acting as chemical catalyst, SARS-CoV-2 accelerates hydrophobic collapse and the heterogeneous nucleation of amorphous amyloids into stable β-sheet aggregates. The clearance of amyloid aggregates is most effective during slow wave sleep, when high levels of adenosine triphosphate (ATP)—a biphasic modulator of biomolecular condensates—and melatonin are available to solubilize amyloid aggregates for removal. The dysregulation of mitochondrial dynamics by SARS-CoV-2, in particular fusion and fission homeostasis, impairs the proper formation of distinct mitochondrial subpopulations that can remedy challenges created by the diversion of substrates away from oxidative phosphorylation towards glycolysis to support viral replication and maintenance. The subsequent reduction of ATP and inhibition of melatonin synthesis during slow wave sleep results in incomplete brain clearance of amyloid aggregates, leading to the development of neurological manifestations commonly associated with age-related neurodegenerative disorders. Exogenous melatonin not only prevents mitochondrial dysfunction but also elevates ATP production, effectively augmenting the solubilizing effect of the adenosine moiety to ensure the timely, optimal disaggregation and clearance of pathogenic amyloid aggregates in the prevention and attenuation of Neuro-PASC.

There is a complex relationship between circadian rhythm dysfunctions and various psychiatric disorders. Circadian (~24 h) rhythms indicate the rhythmic change of different physiological activities in relation to the environmental light-dark cycle. Shift work, light exposure at night, and chronic and acute jet lag affect circadian rhythm that have a negative impact on psychological functions, and behaviors. Additionally, professional stress, mental instability, and social disintegration influence psychiatric disorders. PubMed/MEDLINE, Springer Nature, Science Direct (Elsevier), Wiley Online, ResearchGate, and Google Scholar databases were searched to collect relevant articles. Circadian rhythm disruption causes impaired neurotransmitter release, impaired melatonin and cortisol rhythm, metabolic dysfunctions, neuroinflammation, and neural apoptosis; collectively these factors influence the development of psychiatric disorders. Circadian dysfunction also alters the expression of several clock control genes in the mesolimbic areas that are associated with pathologies of psychiatric disorders. Additionally, chronotherapy and applications of anti-psychotic medicine can improve psychiatric diseases. This review focuses on the effects of circadian clock dysfunction on the vulnerability of psychiatric disorders and the implications of chronotherapy.

Depression poses a significant global health burden, yet current therapeutic approaches focusing on monoaminergic neurotransmission often fall short of achieving full remission and managing acute episodes effectively. This article explores novel treatment avenues beyond conventional monoaminergic approaches, focusing on emerging strategies targeting glutamatergic modulation, electrophysiological/magnetic brain stimulation techniques, anti-inflammatory agents, gut-brain axis interventions, gamma-aminobutyric acid (GABA) modulation, and psychedelic-assisted therapy. Through a narrative review of recent literature, this paper elucidates the mechanisms, clinical efficacy, safety profiles, and future directions of these innovative treatments. These insights offer valuable perspectives for advancing depression management and bridging existing therapeutic gaps.

Stroke is a leading cause of morbidity and mortality. The advent of mechanical thrombectomy has largely improved patient outcomes. This article reviews the features and outcomes associated with aspiration, stent retrievers, and combination catheters used in current practice. There is also a discussion on clinical considerations based on anatomical features and clot composition. The reperfusion grading scale and outcome metrics commonly used following thrombectomy when a patient is still in the hospital are reviewed. Lastly, there are proposed discharge and outpatient follow-up goals in caring for patients hospitalized for a stroke.

Bipolar disorder (BD) is a debilitating psychiatric disorder characterized by recurrent depression, mania, and hypomania episodes. The interaction of psychological, neuropsychological, and neurobiological factors (cognitive, behavioral, and emotional) is implicated in the development and persistence of BD. Accordingly, almost all investigators confirm that BD is the outcome of psychological and genetic interactions. Therefore, researchers should consider various factors in the psychopathology and psychotherapy of BD. This selective review first reviews research on these factors, then points to a variety of therapeutic methods for BD [interpersonal and social rhythm therapy (IPSRT), cognitive behavioral therapy (CBT), dialectical behavior therapy (DBT), mindfulness-based cognitive therapy (MBCT), and family-focused therapy (FFT)], and finally suggested a new comprehensive integrated model for the assessment and therapy of BD.

Epileptic seizures are prevalent in people with brain vascular abnormalities like arteriovenous malformations (AVMs) and cavernous malformations, greatly affecting their quality of life. The connection between intracranial vascular abnormalities and epilepsy is still under debate. Therefore, investigating epilepsy in individuals with AVMs is a crucial and current research area. This review presents a comprehensive examination of recent developments in epilepsy among individuals with brain AVMs. The authors conducted a detailed analysis of the natural progression, epidemiology, diagnostic methods, therapeutic approaches, and post-treatment outcomes for individuals with epilepsy associated with AVMs.

The two mainstays of therapy for refractory epilepsy are medication and surgery. Child behavioral and cognitive aspects of epilepsy can be improved by using a specialized dietary regimen such as the ketogenic diet (KD). The purpose of this review is to expand our understanding of KD as a nutritional therapy for children with refractory epilepsy and to provide insight into the physiological aspects of its efficacy as an alternative to anti-seizure medication. Either directly or indirectly, ketones, glucose restriction, and polyunsaturated fatty acids regulate epileptic seizures. For KD to be effective, all three of these components must be present, even though the exact mechanism is unknown. Increasing gamma-aminobutyric acid, mitochondrial biogenesis, and oxidative phosphorylation levels can also serve as a means of promoting stable synaptic function while also decreasing neural activity and excitability. Most side effects of KD are caused by mild metabolic abnormalities such as acidosis, hyperuricemia, hypercholesterolemia, hypocalcemia, and hypomagnesemia. Since medium-chain triglycerides (MCTs) produce more ketones per calorie than long-chain triglycerides, individuals who consume MCTs can consume more carbohydrates and protein. This review demonstrated that KD therapy led to positive outcomes for patients with refractory epilepsy. Further study is needed to evaluate whether less restrictive and easier-to-follow diets, such as the modified Atkins diet and MCT diets, have a similar effect on seizure treatment as the standard KD.

Receptor tyrosine kinases (RTKs) are known to perform versatile roles in disease landscapes, which determine the fate of the cell. Although much has been discussed from the perspective of proliferation, this review focuses on the impact of RTK-mediated signaling and its role in cytoskeletal degradation, the penultimate stage of cellular degeneration. In the case of degenerative diseases such as Alzheimer’s disease (AD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), age-related macular degeneration (AMD), and type 2 diabetes mellitus (T2DM), RTK signaling has been reported to be perturbed in several studies. The implications of downstream signaling via these receptors through canonical and noncanonical pathways alter the status of actin filaments that provide structural integrity to cells. Degenerative signaling leads to the altered status of rat sarcoma (Ras), Ras homologous (Rho), Ras-related C3 botulinum toxin substrate (Rac), and cell division control protein 42 (Cdc42), the best-characterized components of the cytoskeleton remodeling machinery. RTKs, along with their diverse adaptor partners and other membrane receptors, affect the functionality of Rho family guanosine triphosphate hydrolases (GTPases), which are discussed in this review. To conclude, this review focuses on therapeutic strategies targeting RTKs and Rho GTPase-mediated pathways that can be more effective due to their combined multifactorial impact on neurodegenerative cascades.

Neurodegenerative disorders, including Alzheimer’s, Parkinson’s, Huntington’s, and amyotrophic lateral sclerosis, are among the most significant health concerns worldwide, characterized by neuronal dysfunction, oxidative stress, neuroinflammation, and protein misfolding. Epigallocatechin gallate, a green tea polyphenol, has been reported to possess multifaceted neuroprotective properties. It reduces oxidative stress through free radical scavenging, activation of antioxidant enzymes, and stabilization of mitochondrial function. It also inhibits neuroinflammation through modulation of key signaling pathways. It suppresses amyloid-beta aggregation in Alzheimer’s and alpha-synuclein fibrillation in Parkinson’s, thus attenuating toxic protein accumulation. Its activity in the induction of autophagy and promotion of synaptic plasticity supports neuronal survival and function. However, low bioavailability and metabolic instability hinder its translation into the clinic. Strategies including nanoparticle encapsulation, structural modifications, and combination therapies are being explored to overcome these challenges. Future research could establish epigallocatechin gallate as a viable candidate for managing neurodegenerative disorders.

This brief statement describes some recent achievements of neuropathological research, with the focus on Alzheimer’s and other age-related diseases, neurodegenerative disorders (tauopathies, synucleinopathies), multimorbidity of the aged brain, multiple sclerosis (MS), and other neuroinflammatory disorders, including central nervous system involvement by coronavirus disease 2019 (COVID-19), as well as new developments in neurovascular diseases, neurooncology, and myopathies. Although neuropathology, using modern technologies, such as cryo-electron microscopy, proteomic and experimental methods, has helped to increase diagnostic accuracy and provided insight into the pathogenesis of many neurological disorders, future studies in co-operation with clinical and other neurosciences should overcome the challenges of disease-influencing therapeutic approaches.