Brain and neuroscience advances最新文献

Mental disorders pose a significant global burden and constitute a major cause of disability worldwide. Despite strides in treatment, a substantial number of patients do not respond adequately, underscoring the urgency for innovative approaches. Traditional non-invasive brain stimulation techniques show promise, yet grapple with challenges regarding efficacy and specificity. Variations in mechanistic understanding and reliability among non-invasive brain stimulation methods are common, with limited spatial precision and physical constraints hindering the ability to target subcortical areas often implicated in the disease aetiology. Novel techniques such as transcranial ultrasonic stimulation and temporal interference stimulation have gained notable momentum in recent years, possibly addressing these shortcomings. Transcranial ultrasonic stimulation (TUS) offers exceptional spatial precision and deeper penetration compared with conventional electrical and magnetic stimulation techniques. Studies targeting a diverse array of brain regions have shown its potential to affect neuronal excitability, functional connectivity and symptoms of psychiatric disorders such as major depressive disorder. Nevertheless, challenges such as target planning and addressing acoustic interactions with the skull must be tackled for its widespread adoption in research and potentially clinical settings. Similar to transcranial ultrasonic stimulation, temporal interference (TI) stimulation offers the potential to target deeper subcortical areas compared with traditional non-invasive brain stimulation, albeit requiring a comparatively higher current for equivalent neural effects. Promising yet still sparse research highlights TI's potential to selectively modulate neuronal activity, showing potential for its utility in psychiatry. Overall, recent strides in non-invasive brain stimulation methods like transcranial ultrasonic stimulation and temporal interference stimulation not only open new research avenues but also hold potential as effective treatments in psychiatry. However, realising their full potential necessitates addressing practical challenges and optimising their application effectively.

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Apolipoprotein E ε4 is a major genetic risk factor for Alzheimer's disease, and some apolipoprotein E ε4 carriers show Alzheimer's disease-related neuropathology many years before cognitive changes are apparent. Therefore, studying healthy apolipoprotein E genotyped individuals offers an opportunity to investigate the earliest changes in brain measures that may signal the presence of disease-related processes. For example, subtle changes in functional magnetic resonance imaging functional connectivity, particularly within the default mode network, have been described when comparing healthy ε4 carriers to ε3 carriers. Similarly, very mild impairments of episodic memory have also been documented in healthy apolipoprotein E ε4 carriers. Here, we use a naturalistic activity (movie watching), and a marker of episodic memory encoding (transient changes in functional magnetic resonance imaging activity and functional connectivity around so-called 'event boundaries'), to investigate potential phenotype differences associated with the apolipoprotein E ε4 genotype in a large sample of healthy adults. Using Bayes factor analyses, we found strong evidence against existence of differences associated with apolipoprotein E allelic status. Similarly, we did not find apolipoprotein E-associated differences when we ran exploratory analyses examining: functional system segregation across the whole brain, and connectivity within the default mode network. We conclude that apolipoprotein E genotype has little or no effect on how ongoing experiences are processed in healthy adults. The mild phenotype differences observed in some studies may reflect early effects of Alzheimer's disease-related pathology in apolipoprotein E ε4 carriers.

Humans feel visceral disgust when faced with potential contaminants like bodily effluvia. The emotion serves to reject potentially contaminated food and is paired with proto-nausea: alterations in gastric rhythm in response to disgust. Here, we offer a narrative synthesis of the existing literature on the effects of disgust on the stomach as measured through electrogastrography, a non-invasive technique that measures stomach activity with electrodes placed on the abdominal skin surface. After identifying and assessing 368 studies for eligibility and inclusion based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses process, we reviewed a final sample of only 10 articles that employed electrogastrography to assess gastric responses to unpleasant stimuli, including disgust elicitors. Reviewed findings illustrate that changes in gastric rhythm are associated with negatively valenced emotions, and most reliably with visceral disgust elicitors. This rhymes with recent evidence for a causal role of gastric state in reductions in visceral disgust avoidance. Because limitations in the reviewed body of work come from the low number of studies and relatively small sample sizes, we strongly encourage studies of proto-nausea in designs with higher statistical power, ideally paired with experimental manipulations of gastric state.

Considering the broad scope covered by the field of neuroscience, this study compares neuroscience undergraduate degree programmes across the United Kingdom, with a focus on the distribution of core and optional neuroscience-specific modules. Data from 13 universities were analysed; this revealed significant variation in the proportion of NS module credits acquired by graduation, ranging from 28% to 100% across institutions. The findings highlight particularly low core NS content in Year 1, potentially affecting informed choice of subsequent modules. The observed flexibility in module selection throughout a neuroscience undergraduate degree is a promising opportunity for students to explore their interdisciplinary interests. However, in response to the high variability in NS core and total credits demonstrated by this research, this study calls for further discussion on establishing an accreditation framework to ensure consistency in neuroscience undergraduate degrees across the United Kingdom.

Although a role of the thalamus in different arousal and awareness states is well established, there is a surprising lack of knowledge on subregional specificity within this complex, multinucleated structure of the diencephalon. In their recent paper 'Extrasynaptic GABA-A receptors in central medial thalamus mediate anaesthesia in rats', Muheyati et al. evaluated whether GABA_A receptors expressed in the central medial (CM), paraventricular (PV) or lateral mediodorsal (MD) nuclei of the thalamus contribute to the loss of the righting reflex (LORR) in rats. Deficits in this reflex have previously been interpreted as a surrogate marker of altered levels of consciousness. Using a range of convergent techniques, the authors report the novel finding that delta subunit-expressing GABA_A receptors in the CM contribute to distinct awareness states. This important discovery implicates a tonic GABA_A-mediated conductance in the CM that may be relevant for minimally conscious states and other conditions of altered awareness.