The effect of computerized cognitive training and transcranial direct current stimulation on working memory among post-stroke individuals: a systematic review with meta-analysis and meta-regression.

BACKGROUND: Working memory (WM) impairment is a common phenomenon after stroke; however, its management in rehabilitation is less researched. This systematic review and meta-analysis aimed to provide a quantitative synthesis of the impact of computerised cognitive training (CCT) and transcranial direct current stimulation (tDCS) on WM span in post-stroke individuals. METHODS: The literature search in PubMed, Embase, Scopus, and Cochrane Library focused on randomized controlled trials testing the effect of CCT and tDCS on treated stroke patients as compared to untreated controls. Neuropsychological instruments such as Digit Span Forward/Backward and Visual Span Forward Tests defined the outcome of WM span. After extracting study characteristics and quality assessment using the Cochrane Risk of Bias Tool, we conducted a meta-analysis and meta-regression using standardised mean differences. RESULTS: The search yielded 4142 articles, nine of which (N = 461) fulfilled the inclusion criteria. In the case of CCT, we found significant improvement in Digit Span Backward Test (Z = 2.65, P = 0.008; 95% CI [0.10, 0.67]) and Visual Span Forward Test performance (Z = 3.05, P = 0.002; 95% CI [0.15, 0.69]), while for tDCS, we could not find a sufficient number of studies for the analysis. Furthermore, no significant moderating factor was found in the meta-regression. CONCLUSIONS: In conclusion, CCT appears to be a suitable choice to enhance WM span performance after stroke. However, further research is needed to investigate the effect of tDCS due to the limited number of studies. TRIAL REGISTRATION: The meta-analysis was conducted according to PRISMA (Preferred Reporting of Systematic Reviews and Meta-Analyses) standards with a PROSPERO registration protocol (ID: CRD42023387182).

Revolutionizing our understanding of Parkinson's disease: Dr. Heinz Reichmann's pioneering research and future research direction.

Millions of individuals around the world are afflicted with Parkinson's disease (PD), a prevalent and incapacitating neurodegenerative disorder. Dr. Reichmann, a distinguished professor and neurologist, has made substantial advancements in the domain of PD research, encompassing both fundamental scientific investigations and practical applications. His research has illuminated the etiology and treatment of PD, as well as the function of energy metabolism and premotor symptoms. As a precursor to a number of neurotransmitters and neuromodulators that are implicated in the pathophysiology of PD, he has also investigated the application of tryptophan (Trp) derivatives in the disease. His principal findings and insights are summarized and synthesized in this narrative review article, which also emphasizes the challenges and implications for future PD research. This narrative review aims to identify and analyze the key contributions of Reichmann to the field of PD research, with the ultimate goal of informing future research directions in the domain. By examining Reichmann's work, the study seeks to provide a comprehensive understanding of his major contributions and how they can be applied to advance the diagnosis and treatment of PD. This paper also explores the potential intersection of Reichmann's findings with emerging avenues, such as the investigation of Trp and its metabolites, particularly kynurenines, which could lead to new insights and potential therapeutic strategies for managing neurodegenerative disorders like PD.

The role of kynurenines in migraine-related neuroimmune pathways.

Migraine, a primary headache disorder whose mechanism remains incompletely understood, appears to involve the activation of the trigeminovascular system (TS) during attacks. Research suggests that inflammatory processes mediated by the immune system may play a role in migraine pathophysiology. Neuroinflammation is often associated with migraine attacks, with cytokines serving as crucial mediators in the process. Elevated levels of pro-inflammatory cytokines, such as interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), have been observed in the blood and cerebrospinal fluid of individuals experiencing migraine attacks. These cytokines have the capacity to sensitize pain pathways in the brain, thereby increasing sensitivity to pain stimuli. This phenomenon, known as central sensitization, is believed to contribute to the intensity and persistence of migraine pain. Kynurenines, endogenous mediators of glutamatergic mechanisms, can significantly influence the pathophysiology of primary headache disorders. The kynurenine system is collectively known as the kynurenine pathway (KP), which can act on multiple receptors, such as glutamate receptors, aryl hydrocarbon receptors (AhRs), G protein-coupled receptors 35 (GPR35), and α-7 nicotinic acetylcholine (α7 nACh) receptors. These receptors are also found on various cells of the immune system, so the role of the KP in the pathomechanism of primary headaches may also be mediated through them. In this review, our goal is to show a possible link between the receptors of the KP and immune system in the context of inflammation and migraine. Migraine research in recent years has focused on neuropeptides, such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) as potential pathogenic factors and possible therapeutic approaches. These peptides share many similarities in their characteristics and roles. For instance, they exhibit potent vasodilation, occur in both the peripheral and central nervous systems, and play a role in transmitting nociception and neurogenic inflammation. The investigation of potential connections between the aforementioned neuropeptides and the kynurenine pathway could play a significant role in uncovering the pathomechanism of migraine and identifying new drug candidates.

Validation of the Fatigue Impact Scale in Multiple Sclerosis Patients in Serbia.

Fatigue is one of the most frequent complaints of patients with multiple sclerosis (MS). The Fatigue Impact Scale (FIS), one of the 30 available fatigue questionnaires, is commonly applied because it evaluates multidimensional aspects of fatigue. The chief objectives of this study were to validate FIS and evaluate the psychometric properties of MS patients in Serbia. One hundred and twenty-one (121) MS patients and one hundred and twenty-two (122) age-, gender- and education-matched healthy control (HC) subjects completed the FIS and the Beck Depression Inventory. Internal consistency of the FIS subscales was determined using Cronbach's Alpha Coefficient. Test/retest reliability with an intra-class correlation coefficient (ICC) for each FIS subscale was performed. The total FIS score and subscale scores showed statistically significant differences between the MS patients and the HC subjects in both FIS sessions. Cronbach's Alpha was 0.966. All ICCs were statistically significant (p < 0.05). The Serbian version of this instrument may be useful as a clinical measure for fatigue and functionality in patients with MS.

Kynurenic acid protects against ischemia/reperfusion injury by modulating apoptosis in cardiomyocytes.

Acute myocardial infarction, often associated with ischemia/reperfusion injury (I/R), is a leading cause of death worldwide. Although the endogenous tryptophan metabolite kynurenic acid (KYNA) has been shown to exert protection against I/R injury, its mechanism of action at the cellular and molecular level is not well understood yet. Therefore, we examined the potential involvement of antiapoptotic mechanisms, as well as N-methyl-D-aspartate (NMDA) receptor modulation in the protective effect of KYNA in cardiac cells exposed to simulated I/R (SI/R). KYNA was shown to attenuate cell death induced by SI/R dose-dependently in H9c2 cells or primary rat cardiomyocytes. Analysis of morphological and molecular markers of apoptosis (i.e., membrane blebbing, apoptotic nuclear morphology, DNA double-strand breaks, activation of caspases) revealed considerably increased apoptotic activity in cardiac cells undergoing SI/R. The investigated apoptotic markers were substantially improved by treatment with the cytoprotective dose of KYNA. Although cardiac cells were shown to express NMDA receptors, another NMDA antagonist structurally different from KYNA was unable to protect against SI/R-induced cell death. Our findings provide evidence that the protective effect of KYNA against SI/R-induced cardiac cell injury involves antiapoptotic mechanisms, that seem to evoke independently of NMDA receptor signaling.

Navigating the Neurobiology of Migraine: From Pathways to Potential Therapies.

Migraine is a debilitating neurological disorder characterized by recurring episodes of throbbing headaches that are frequently accompanied by sensory disturbances, nausea, and sensitivity to light and sound [...].

Pituitary cyclase-activating polypeptide targeted treatments for the treatment of primary headache disorders.

OBJECTIVE: Migraine is a complex and disabling neurological disorder. Recent years have witnessed the development and emergence of novel treatments for the condition, namely those targeting calcitonin gene-related peptide (CGRP). However, there remains a substantial need for further treatments for those unresponsive to current therapies. Targeting pituitary adenylate cyclase-activating polypeptide (PACAP) as a possible therapeutic strategy in the primary headache disorders has gained interest over recent years. METHODS: This review will summarize what we know about PACAP to date: its expression, receptors, roles in migraine and cluster headache biology, insights gained from preclinical and clinical models of migraine, and therapeutic scope. RESULTS: PACAP shares homology with vasoactive intestinal polypeptide (VIP) and is one of several vasoactive neuropeptides along with CGRP and VIP, which has been implicated in migraine neurobiology. PACAP is widely expressed in areas of interest in migraine pathophysiology, such as the thalamus, trigeminal nucleus caudalis, and sphenopalatine ganglion. Preclinical evidence suggests a role for PACAP in trigeminovascular sensitization, while clinical evidence shows ictal release of PACAP in migraine and intravenous infusion of PACAP triggering attacks in susceptible individuals. PACAP leads to dural vasodilatation and secondary central phenomena via its binding to different G-protein-coupled receptors, and intracellular downstream effects through cyclic adenosine monophosphate (cAMP) and phosphokinase C (PKC). Targeting PACAP as a therapeutic strategy in headache has been explored using monoclonal antibodies developed against PACAP and against the PAC1 receptor, with initial positive results. INTERPRETATION: Future clinical trials hold considerable promise for a new therapeutic approach using PACAP-targeted therapies in both migraine and cluster headache.

Innovation at the Intersection: Emerging Translational Research in Neurology and Psychiatry.

Translational research in neurological and psychiatric diseases is a rapidly advancing field that promises to redefine our approach to these complex conditions [...].

A Decade of Dedication: Pioneering Perspectives on Neurological Diseases and Mental Illnesses.

Welcome to Biomedicines' 10th Anniversary Special Issue, a journey through the human mind's labyrinth and complex neurological pathways [...].

Neural Correlates and Molecular Mechanisms of Memory and Learning.

Memory and learning are essential cognitive processes that enable us to obtain, retain, and recall information [...].

Neurodegeneration in Cognitive Impairment and Mood Disorders for Experimental, Clinical and Translational Neuropsychiatry.

Neurodegeneration poses a significant challenge for the fields of neuroscience and medicine, as it is the underlying cause of the development and advancement of numerous neurodegenerative and psychiatric disorders [...].

From Lab to Life: Exploring Cutting-Edge Models for Neurological and Psychiatric Disorders.

Neuroscience, neurology, and psychiatry are rapidly evolving fields that aim to understand the complex mechanisms underlying brain function and dysfunction, as well as to develop effective interventions for various neurological and psychiatric disorders [...].

The Impact of C-3 Side Chain Modifications on Kynurenic Acid: A Behavioral Analysis of Its Analogs in the Motor Domain.

The central nervous system (CNS) is the final frontier in drug delivery because of the blood-brain barrier (BBB), which poses significant barriers to the access of most drugs to their targets. Kynurenic acid (KYNA), a tryptophan (Trp) metabolite, plays an important role in behavioral functions, and abnormal KYNA levels have been observed in neuropsychiatric conditions. The current challenge lies in delivering KYNA to the CNS owing to its polar side chain. Recently, C-3 side chain-modified KYNA analogs have been shown to cross the BBB; however, it is unclear whether they retain the biological functions of the parent molecule. This study examined the impact of KYNA analogs, specifically, SZR-72, SZR-104, and the newly developed SZRG-21, on behavior. The analogs were administered intracerebroventricularly (i.c.v.), and their effects on the motor domain were compared with those of KYNA. Specifically, open-field (OF) and rotarod (RR) tests were employed to assess motor activity and skills. SZR-104 increased horizontal exploratory activity in the OF test at a dose of 0.04 µmol/4 µL, while SZR-72 decreased vertical activity at doses of 0.04 and 0.1 µmol/4 µL. In the RR test, however, neither KYNA nor its analogs showed any significant differences in motor skills at either dose. Side chain modification affects affective motor performance and exploratory behavior, as the results show for the first time. In this study, we showed that KYNA analogs alter emotional components such as motor-associated curiosity and emotions. Consequently, drug design necessitates the development of precise strategies to traverse the BBB while paying close attention to modifications in their effects on behavior.

Kynurenines, Neuronal Excitotoxicity, and Mitochondrial Oxidative Stress: Role of the Intestinal Flora.

The intestinal flora has been the focus of numerous investigations recently, with inquiries not just into the gastrointestinal aspects but also the pathomechanism of other diseases such as nervous system disorders and mitochondrial diseases. Mitochondrial disorders are the most common type of inheritable metabolic illness caused by mutations of mitochondrial and nuclear DNA. Despite the intensive research, its diagnosis is usually difficult, and unfortunately, treating it challenges physicians. Metabolites of the kynurenine pathway are linked to many disorders, such as depression, schizophrenia, migraine, and also diseases associated with impaired mitochondrial function. The kynurenine pathway includes many substances, for instance kynurenic acid and quinolinic acid. In this review, we would like to show a possible link between the metabolites of the kynurenine pathway and mitochondrial stress in the context of intestinal flora. Furthermore, we summarize the possible markers of and future therapeutic options for the kynurenine pathway in excitotoxicity and mitochondrial oxidative stress.

The Orexin/Hypocretin System, the Peptidergic Regulator of Vigilance, Orchestrates Adaptation to Stress.

The orexin/hypocretin neuropeptide family has emerged as a focal point of neuroscientific research following the discovery that this family plays a crucial role in a variety of physiological and behavioral processes. These neuropeptides serve as powerful neuromodulators, intricately shaping autonomic, endocrine, and behavioral responses across species. Notably, they serve as master regulators of vigilance and stress responses; however, their roles in food intake, metabolism, and thermoregulation appear complementary and warrant further investigation. This narrative review provides a journey through the evolution of our understanding of the orexin system, from its initial discovery to the promising progress made in developing orexin derivatives. It goes beyond conventional boundaries, striving to synthesize the multifaceted activities of orexins. Special emphasis is placed on domains such as stress response, fear, anxiety, and learning, in which the authors have contributed to the literature with original publications. This paper also overviews the advancement of orexin pharmacology, which has already yielded some promising successes, particularly in the treatment of sleep disorders.

DNA methylome, R-loop and clinical exome profiling of patients with sporadic amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the death of motor neurons, the aetiology of which is essentially unknown. Here, we present an integrative epigenomic study in blood samples from seven clinically characterised sporadic ALS patients to elucidate molecular factors associated with the disease. We used clinical exome sequencing (CES) to study DNA variants, DNA-RNA hybrid immunoprecipitation sequencing (DRIP-seq) to assess R-loop distribution, and reduced representation bisulfite sequencing (RRBS) to examine DNA methylation changes. The above datasets were combined to create a comprehensive repository of genetic and epigenetic changes associated with the ALS cases studied. This repository is well-suited to unveil new correlations within individual patients and across the entire patient cohort. The molecular attributes described here are expected to guide further mechanistic studies on ALS, shedding light on the underlying genetic causes and facilitating the development of new epigenetic therapies to combat this life-threatening disease.

The 7-year follow-up of the Hungarian BICAMS validation cohort implies that cognitive performance may improve in multiple sclerosis patients.

BACKGROUND: Cognitive impairment (CI) is a frequent symptom of multiple sclerosis (MS) and has a great impact on the patients' quality of life, so screening is essential. The brief international cognitive assessment for multiple sclerosis (BICAMS) was developed for this purpose. However, longitudinal data is lacking with the use of the battery. OBJECTIVE: This study is to assess the performance of patients after 5 and 7 years of the original BICAMS validation study and to identify any influencing factors. METHODS: BICAMS was used to measure cognitive function of 52 relapsing-remitting MS patients (RRMS) from the original validation study after 5 years (n = 43) and again, after 7 years (n = 42). Patients filled out the fatigue impact scale (FIS) and multiple sclerosis quality of life-54 (MSQoL-54) questionnaire, and we evaluated expanded disability status scale (EDSS). RESULTS: There was an improvement in the BVMT-R and the CVLT-II assessments at both the 5-year (p<0.001 and p=0.025) and the 7-year retest (p<0.001 and p=0.002). The prevalence of CI significantly decreased at the 5-year mark (p=0.021) but remained stable after that. There was no deterioration in MSQoL scores during the study. The basic cognitive performance is the most important influencing factor, but the duration of the disease, the EDSS score, and the escalation of the therapy also affect the cognitive scores. CONCLUSION: This is the longest longitudinal study utilizing the BICAMS battery, reinforcing its feasibility as a clinical screening tool. It seems that cognitive performance may improve in the long term and early initiation of effective therapy may influence this outcome.

Ion Channel Disturbances in Migraine Headache: Exploring the Potential Role of the Kynurenine System in the Context of the Trigeminovascular System.

Migraine is a primary headache disorder, which is an enormous burden to the healthcare system. While some aspects of the pathomechanism of migraines remain unknown, the most accepted theory is that activation and sensitization of the trigeminovascular system are essential during migraine attacks. In recent decades, it has been suggested that ion channels may be important participants in the pathogenesis of migraine. Numerous ion channels are expressed in the peripheral and central nervous systems, including the trigeminovascular system, affecting neuron excitability, synaptic energy homeostasis, inflammatory signaling, and pain sensation. Dysfunction of ion channels could result in neuronal excitability and peripheral or central sensitization. This narrative review covers the current understanding of the biological mechanisms leading to activation and sensitization of the trigeminovascular pain pathway, with a focus on recent findings on ion channel activation and modulation. Furthermore, we focus on the kynurenine pathway since this system contains kynurenic acid, which is an endogenous glutamate receptor antagonist substance, and it has a role in migraine pathophysiology.

Personality traits and psychological complaints under patients suffering from headaches.

Background and purpose:

Although headaches are often comorbid with psychological symptoms, the underlying psychological processes, e.g. the role of personality dimensions as headache determinants remains unclear. Studies found associations between headaches and various personality traits; according to the Big Five model of personality, persons suffering from headaches exhibit a higher rate in neuroticism, while a lower rate in extraversion, openness to experiences and positive emotions. This is the first study to clarify the associations among duration, intensity, and frequency of headaches and personality dimensions. Through this study we could get into the personality dimensions in the background of pain experience and that which personality dimensions bear a part in the behaviour of the persons, who suffered from headache, but do not seek treatment through this complaint. 

Treated (Group1) and untreated (Group2) headache patients and healthy controls (Group3) were investigated (total of 360 participants). The main headache components of intensity, duration, and frequency were used as dependent variables with personality dimensions in the Big Five concept investigated by the NEO-PI-R Personality Inventory.

Employing multiple regression analysis, facets of personality described 14.7% of headache intensity, 10.9 % of duration, and 18.7 % of frequency variance. Group1 and Group2 reached significantly higher values on the dimension of anxiety, depression, and vulnerability to stress than Group3. Group1 showed a significantly higher value on trust personality dimension than Group3 and Group2. Group3 exhibited a significantly higher value in the trust dimension than Group2. Concerning vulnerability to stress, the highest value was yielded by the “treated and suffering from headaches” group and there was a significant difference also with the “untreated and suffering from headaches” group and with the control group. In this dimension, the “untreated and suffering from headaches” group’s point value was significantly higher than the control group’s (p<0.01, U=-4.501).

Our study demonstrates that the three headache components are not independent from personality traits, and personality traits may interact with treatment seeking behavior even in the presence of significant headache complaints. The role of the personality traits are significant in the intensity, duration and frequency of headaches. 

Emerging Translational Research in Neurological and Psychiatric Diseases: From In Vitro to In Vivo Models.

Revealing the underlying pathomechanisms of neurological and psychiatric disorders, searching for new biomarkers, and developing novel therapeutics all require translational research [...].