Brain Sciences最新文献

Background/Objectives: Unilateral hand movements alter the excitability of the ipsilateral primary motor cortex (ipsi-M1) and contralateral spinal motoneurons. Although this excitability increases during complex, high muscle-activity movements, few studies have examined the excitability of ipsi-M1 and contralateral spinal motoneurons during complex movements while accounting for muscle activity. This study investigated the excitability of ipsi-M1 and contralateral spinal motoneurons during complex and simple movement tasks with comparable muscle activity between the two tasks. Methods: Nineteen healthy adult volunteers participated in this study. The ball rotation task was set as the complex movement task (BR condition), and the grasping task was set as the simple movement task (grasp condition), with peak muscle activity values comparable between the tasks. Motor-evoked potentials (MEPs) and F-waves were recorded from the abductor pollicis brevis muscle contralateral to the movement during task execution. The excitability parameters of ipsi-M1 and contralateral spinal motoneurons were calculated by dividing the MEP, F-wave persistence, and F/M amplitude values recorded in each condition by the corresponding values recorded at rest. These parameters were compared across the rest, BR, and grasp conditions. Results: All the excitability parameters of ipsi-M1 and contralateral spinal motoneurons increased during both the BR and grasp conditions compared with the rest condition but did not differ significantly between the BR and grasp conditions. Conclusions: The excitability of ipsi-M1 and contralateral spinal motoneurons was strongly influenced by the amount of muscle activity but not by the complexity of the movement.

Background/objectives: The misuse of veterinary drugs is a growing concern, with increasing evidence of their presence in illicit drug markets and their use as alternatives to traditional substances.

Methods: This study explores Reddit discussions on the misuse of veterinary drugs on Reddit, focusing on xylazine, carfentanil, medetomidine, pentobarbital, phenylbutazone, and acepromazine. Reddit was utilised for its abundant real-time data on users' thoughts and experiences with substance misuse. Through a combination of manual and Artificial Intelligence (AI)-driven thematic analysis, we examined posts and comments to explore patterns of misuse.

Results: The themes analysed included adverse effects, polysubstance misuse, routes of administration, motivations for misuse, and methods of obtaining these drugs. Our findings revealed that xylazine, medetomidine, carfentanil, and pentobarbital exhibit significant potential for misuse, while phenylbutazone and acepromazine are not widely misused. Despite this, phenylbutazone and acepromazine have been identified as adulterants in the illicit drug supply in the United States. The most discussed themes included motivations for misuse, followed by public experiences and perceptions, as well as adverse effects.

Conclusions: The dual-method approach of combining manual interpretation with AI analysis allowed for a comprehensive understanding of social media discussions. This research highlights the importance of monitoring online platforms for early indicators of emerging drug trends, offering valuable insights to inform public health policies and intervention strategies. Impact Statement: This research highlights the growing public health risk posed by veterinary drug misuse, underscoring the need for enhanced monitoring, regulatory frameworks, and education to address their diversion into illicit markets. By leveraging social media as an early detection tool for emerging drug trends, our findings can inform targeted interventions.

Background: Transient ischemic attack (TIA) is a recognized precursor of stroke that also indicates a high risk of recurrence. The Hyperintense Acute Reperfusion Marker (HARM), which is linked to blood-brain barrier disruption, may serve as a novel imaging biomarker for TIA.

Methods: A retrospective cohort study of 715 patients with TIA evaluated the predictive value of HARM for stroke recurrence and its association with TOAST subtype. Imaging findings, including those of diffusion-weighted imaging, were analyzed using logistic regression.

Results: HARM-positive patients had significantly higher recurrence rates at 3 months (20.9%; odds ratio [OR] = 5.3) and 1 year (30.2%; OR = 5.8) compared to HARM-negative patients, relative to other imaging markers (p < 0.001). HARM was significantly associated with the cardioembolic stroke (p < 0.001).

Conclusions: HARM is a promising imaging biomarker for predicting stroke recurrence and etiology in patients experiencing TIA. Incorporating HARM into clinical frameworks may enhance diagnostic and prognostic accuracy.

Background: Sexual characteristics in brain neurophysiological activity are a significant area of research in cognitive neuroscience. As a sport that involves minimal physical movement, shooters remain largely stationary during aiming, facilitating the collection of their neural activity compared to athletes in other sports. Objectives: To investigate the neural characteristics of novice shooters of different genders under competitive conditions. Methods: Sixteen subjects participated in a shooting competition following four weeks of training. Electroencephalogram (EEG) data and behavioral data (shooting scores, aiming curves, and pressure curves) were recorded during the competition, and the power spectral density (PSD) and phase-locking value (PLV) network features were extracted to explore further the correlation between the shooting scores and neural activity. Results: In our sample, (1) there were no significant differences in shooting scores between males and females; (2) there were differences in PSD values across the theta, alpha, alpha-2, beta, and gamma frequency bands between males and females; and (3) there were differences in PLV network properties in the theta, alpha, beta, and gamma frequency bands between males and females. Correlation analysis revealed associations between shooting scores and neural activity in male and female novices. Conclusions: The case study demonstrated that males and females exhibited different neural activity characteristics in the shooting competition, providing a foundation for further investigation into the sex differences in neural activity in shooting competition.

Background: Autism spectrum disorder has been argued to involve impairments in domain-general predictive abilities. There is strong evidence that individuals with ASD have trouble navigating the dynamic world due to an inability to predict the outcomes of particular events. There is also evidence that this is apparent across the diagnostic criteria of ASD and common among correlates of ASD. However, the question remains as to whether this impairment in predictive abilities is domain-specific or domain-general, with little research investigating prediction in linguistic measures.

Methods: The current study investigated whether individuals with ASD showed atypicalities in linguistic prediction using a cloze probability task. In Experiment 1, 33 individuals with ASD were compared to 64 typically developing individuals in an offline cloze task.

Results: There was no significant effect of an ASD diagnosis on the cloze probability. However, individuals with higher levels of autistic traits were significantly more likely to produce lower-probability (non-modal) cloze responses. In Experiment 2, 19 individuals with ASD were compared to 22 typically developing individuals in a lab-based cloze task, in which we also measured the reaction times to begin speaking (i.e., voice onset time). The results showed that individuals with ASD had significantly slower reaction times (~200 ms) but, similarly to Experiment 1, did not show differences in the cloze probability of the responses produced.

Conclusions: We conclude that individuals with ASD do show inefficiency in linguistic prediction, as well as indicating which ASD traits most strongly correlate with these inefficiencies.

Background/Objectives: This study evaluates the potential of electroencephalography (EEG) as a noninvasive tool for distinguishing between healthy individuals (n = 79), those with mild cognitive impairment (MCI; n = 36), and dementia patients (n = 7). Methods: Using a 14-channel Emotiv EPOC-X headset, we analyzed power spectral density during a 2-min eyes-closed resting state. Results: Our results demonstrated that while EEG effectively differentiated dementia patients from healthy controls, it did not show significant differences between MCI and healthy controls. This indicates that EEG holds promise for identifying advanced cognitive decline but faces challenges in early-stage detection. Conclusions: The study contributes to the growing body of literature by highlighting EEG's potential as a cost-effective alternative to invasive diagnostic methods while also identifying the need for larger sample sizes and task-oriented approaches to improve its diagnostic precision.

Cerebral lateralisation is a core organising principle of the brain that is characterised by a complex pattern of hemispheric specialisations and interhemispheric interactions. In various mental disorders, functional and/or structural hemispheric asymmetries are changed compared to healthy controls, and these alterations may contribute to the primary symptoms and cognitive impairments of a specific disorder. Since multiple genetic and epigenetic factors influence both the pathogenesis of mental illness and the development of brain asymmetries, it is likely that the neural developmental pathways overlap or are even causally intertwined, although the timing, magnitude, and direction of interactions may vary depending on the specific disorder. However, the underlying developmental steps and neuronal mechanisms are still unclear. In this review article, we briefly summarise what we know about structural, functional, and developmental relationships and outline hypothetical connections, which could be investigated in appropriate animal models. Altered cerebral asymmetries may causally contribute to the development of the structural and/or functional features of a disorder, as neural mechanisms that trigger neuropathogenesis are embedded in the asymmetrical organisation of the developing brain. Therefore, the occurrence and severity of impairments in neural processing and cognition probably cannot be understood independently of the development of the lateralised organisation of intra- and interhemispheric neuronal networks. Conversely, impaired cellular processes can also hinder favourable asymmetry development and lead to cognitive deficits in particular.

Background: In motor imagery brain-computer interface (MI-BCI) research, electroencephalogram (EEG) signals are complex and nonlinear. This complexity and nonlinearity render signal processing and classification challenging when employing traditional linear methods. Information entropy, with its intrinsic nonlinear characteristics, effectively captures the dynamic behavior of EEG signals, thereby addressing the limitations of traditional methods in capturing linear features. However, the multitude of entropy types leads to unclear application scenarios, with a lack of systematic descriptions. Methods: This study conducted a review of 63 high-quality research articles focused on the application of entropy in MI-BCI, published between 2019 and 2023. It summarizes the names, functions, and application scopes of 13 commonly used entropy measures. Results: The findings indicate that sample entropy (16.3%), Shannon entropy (13%), fuzzy entropy (12%), permutation entropy (9.8%), and approximate entropy (7.6%) are the most frequently utilized entropy features in MI-BCI. The majority of studies employ a single entropy feature (79.7%), with dual entropy (9.4%) and triple entropy (4.7%) being the most prevalent combinations in multiple entropy applications. The incorporation of entropy features can significantly enhance pattern classification accuracy (by 8-10%). Most studies (67%) utilize public datasets for classification verification, while a minority design and conduct experiments (28%), and only 5% combine both methods. Conclusions: Future research should delve into the effects of various entropy features on specific problems to clarify their application scenarios. As research methodologies continue to evolve and advance, entropy features are poised to play a significant role in a wide array of fields and contexts.

Background: The gut microbiome directly impacts brain health and activity, meaning the two are closely associated. This relationship suggests a link between microbial imbalances and diseases such as Alzheimer's, although multiple other contributing factors, such as genetics, also play a part. Additionally, recent studies discovered that cerebrospinal fluid has some microbial deoxyribonucleic acid (DNA), which can be interpreted to mean a microbiome exists in the brain too. The vagus nerve and the central nervous and immune systems are responsible for the connection between the brain and gut microbiome. Aims and Objectives: The main aim of this systematic review is to analyze existing research on the gut-brain axis and the brain microbiome to fill the current knowledge gap. Materials and Methods: A search was conducted on the PubMed database based on a set of predefined MeSH terms. Results: After the search, 2716 articles meeting the MeSH parameters were found in PubMed. This list was then downloaded and analyzed according to the inclusion/exclusion criteria, and 63 relevant papers were selected. Discussion: Bacteria in the gut microbiome produce some substances that are considered neuroactive. These compounds can directly or indirectly affect brain function through the gut-brain axis. However, various knowledge gaps on the mechanisms involved in this connection need to be addressed first.

Oxidative stress levels are exacerbated in Alzheimer's disease (AD). This phenomenon feeds back into the overactivation of oxidase enzymes, mitochondrial dysfunction, and the formation of advanced glycation end-products (AGEs), with the stimulation of their receptors (RAGE). These factors stimulate Aβ peptide aggregation and tau hyperphosphorylation through multiple pathways, which are addressed in this paper. The aim of this study was to evaluate the regulatory effect of N-acetyl cysteine (NAC) on oxidant/antioxidant balance as an adjuvant treatment in patients with AD. The results obtained showed that NAC supplementation produced improved cognitive performance, decreased levels of oxidative stress markers, lowered activities of oxidase enzymes, increased antioxidant responses, and attenuated inflammatory and apoptotic markers. Moreover, NAC reversed mitochondrial dysfunction, lowered AGEs-RAGE formation, attenuated Aβ peptide oligomerization, and reduced phosphorylation of tau, thereby halting the formation of neurofibrillary tangles and the progression of AD.