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PubMed2026

Retinal microstructural alterations as early phenotypes of depression in radiogenomics analysis.

BACKGROUND: With the increasing prevalence of depression, there is an urgent clinical need for early screening in depression. The retina offers a promising window for early screening in depression due to its rapid, non-invasive, objective, eye-brain correlated characteristics, but previous research has yielded conflicting alterations in retinal microstructure in depression. METHODS: We screened retinal optical coherence tomography and brain magnetic resonance imaging data in the UK Biobank to enroll 23,225 participants for retinal study of depression occurrence, and 1475 participants for the eye-brain association study. We also used genetic data (ID: ebi-a-GCST90014267 and ukb-d-20,448) from the Integrative Epidemiology Unit Open Genome-Wide Association Study for Mendelian randomization analysis. We used Cox regression to assess the association between retinal microstructure and depression risk, Mendelian randomization to infer causality, and mediation analysis to explore retina-brain pathway association. RESULTS: The Cox regression analysis showed that retinal ganglion cell-inner plexiform layer (GCIPL) thickness remained a significant predictor of depression. The Mendelian randomization analysis indicated a positive statistical association between GCIPL thickness and depression. Moreover, there was a significant positive correlation (all p < 0.001) between the volume of specific depression-related brain regions and the GCIPL thickness. Adjusting for age, sex, and head size, the mediation analysis provided preliminary evidence for a potential anatomical pathway linking retinal GCIPL thickness to depression-related brain regions through primary visual cortex and secondary visual cortex volumes. CONCLUSION: Thickened retinal GCIPL is a potential early phenotype of depression and has a potential association pathway with depression-related brain regions using a radiogenomics approach.

Humans↗

PubMed2026

Ultra-high-field 7T MRI reveals neural abnormalities of attention networks in relation to cognitive impairment in hypertension.

Hypertension is a significant risk factor for cognitive impairment (CI), yet the corresponding neural network abnormalities remain underexplored. In this study, we examined the associations among global and domain-specific cognitive dysfunction, neuroimaging measures, and blood pressure in a subgroup of hypertensive patients with CI (N = 41) from a randomized controlled trial who underwent ultra-high-field 7 T MRI. Structural atrophy related to CI was localized to regions overlapping the attention networks. Both whole-brain and within-network dysfunction of the attention networks were associated with worse global cognitive performance. Notably, hyperconnectivity within key attention network hubs, including the right anterior insula and posterior intraparietal sulcus, was associated with declined processing speed in hypertensive patients, mediating the association between pulse pressure and processing speed. These findings provide new insights into the neural pathophysiology of hypertension-related CI and suggest potential network-based targets for intervention.

Magnetic Resonance Imaging↗

PubMed2026

Novel splice site variants in GBA1 are associated with Gaucher disease and genotype-phenotype correlations.

BACKGROUND: Variants in GBA1 are associated with neurodegenerative disease. This study aimed to explore pathogenic GBA1 variants. METHODS: Four patients with progressive myoclonic epilepsy (PME) and extremely low β-glucosidase levels were recruited. Whole-exome sequencing and long-range PCR were performed to identify GBA1 variants. Bioinformatic analyses were used to predict the impact of the identified variants. A literature review was performed to explore the genotype-phenotype correlations. GBA1 expression data across different brain regions and developmental stages were analyzed using the BrainSpan database. RT-PCR was performed to verify the splicing effects. RESULTS: Compound heterozygous GBA1 variants were identified in four patients. Five distinct variants were detected, including two novel splice site variants (c.308-2A>G and c.762-2A>C) and three previously reported variants. All identified variants were rare or absent in gnomAD. Splice site variants c.308-2A>G and c.762-2A>C were predicted to cause aberrant splicing. Minigene-based splicing assays coupled with RT-PCR and Sanger sequencing confirmed that both variants cause complete exon skipping (exon 4 and exon 7, respectively). All patients presented with PME onset in childhood/adolescence, intellectual regression, low β-glucosidase, and diffuse brain atrophy and were subsequently diagnosed with Gaucher disease type 3. GBA1 expression in the brain showed two distinct peaks: one in infancy and another after five years of age. The onset age of PME aligned with the second GBA1 expression peak (after five years of age). CONCLUSION: This study identified compound heterozygous GBA1 variants, including two novel candidate pathogenic splice site variants, in Gaucher disease type 3 patients, expanding the known mutational spectrum.

Humans↗

PubMed2026

Pathogenic Variants in HEPACAM Alter Protein Localization and Interactome in Astrocytes of the Developing Mouse Cortex.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy characterized by early-onset macrocephaly, white matter edema, seizures, and motor and cognitive decline. Approximately 25% of MLC patients carry HEPACAM pathogenic variants, many of which are dominant missense variants causing remitting MLC Type 2b. HEPACAM encodes hepatic and glial cell adhesion molecule (hepaCAM), also known as GlialCAM, an astrocyte-enriched transmembrane protein with important roles in astrocyte territory establishment, gap junction coupling, branching organization, synaptic function, and development of the gliovascular unit. The molecular mechanisms through which pathogenic variants in HEPACAM alter hepaCAM protein function in vivo and facilitate MLC pathogenesis during brain development remain largely unknown. Here, we used new viral tools and proximity-based proteomics to examine how three different dominant pathogenic variants alter hepaCAM subcellular localization and protein interactome in astrocytes of the developing mouse cortex. We found dramatic changes in hepaCAM distribution throughout the astrocyte, which were common to all mutants tested. We also observed significant changes in protein interactome between wild type and mutant hepaCAM, including decreased association with previously described hepaCAM-interacting proteins Connexin 43 and CLC-2. Moreover, we identified the epilepsy-associate potassium channel KCNQ2 as a novel hepaCAM interaction partner and found reduced association between KCNQ2 and pathogenic variants. Collectively, our data provide new insights into hepaCAM protein function in astrocytes during brain development, reveal altered protein dynamics of pathogenic variants, and provide a new resource to explore the molecular underpinnings of MLC pathogenesis.

Animals↗

PubMed2026

Long-term outcomes after a randomized phase II trial of nerve growth factor eye drops for optic pathway gliomas: four-year follow-up findings in children.

PURPOSE: A previous double-blind, randomized, placebo-controlled, phase II clinical trial reported beneficial effects of a short-term treatment (10 days) with murine nerve growth factor (mNGF) eye drops on visual function in children with optic pathway gliomas (OPG). The present study aimed to evaluate long-term changes in clinical and neuroradiological parameters in the cohort of OPG patients who had previously participated in the phase II mNGF trial. METHODS: Fifteen of the 18 patients originally enrolled in the phase II mNGF trial agreed to undergo clinical and neuroradiological monitoring over a 48-month follow-up period. Of these, 9 had originally been randomized to mNGF and 6 to placebo; no additional treatment (mNGF, chemotherapy, or radiotherapy) was administered during the extended follow-up. Every 6 months, patients underwent general clinical and neuro-ophthalmological examination, visual evoked potentials (VEP), and photopic negative response of the electroretinogram (PhNR). Brain MRI was performed every 12 months. RESULTS: Comparison of initial and final follow-up median values revealed no statistically significant changes in visual acuity, VEP amplitude, PhNR amplitude, or visual field radius. No significant differences were observed in any parameter relative to baseline values of the mNGF trial. Brain MRI demonstrated stable disease in all patients throughout the observation period. CONCLUSION: These findings, obtained in an observational extension of the original randomized cohort, indicate favorable long-term safety and tolerability of a short-term course of topical mNGF in children with OPG, with sustained visual and neuroradiological stability over four years, rather than evidence of persistent treatment efficacy. Further prospective, adequately powered and randomized clinical studies are needed to confirm both the short- and long-term clinical efficacy of NGF treatment in preventing OPG-induced visual loss.

Humans↗

PubMed2025

Impact of Chewing Behavior Change on Cognition and Cerebral Hemodynamics.

BACKGROUND: Impaired chewing ability is a recognized risk factor for cognitive decline in older adults, potentially due to reduced neural stimulation in cognition-related brain regions. While short-term studies have demonstrated transient increases in neural activity from chewing, the sustained cognitive and neurophysiological effects of encouraging thorough chewing habits in daily life remain unclear. OBJECTIVE: This randomized controlled trial investigated whether promoting thorough chewing during meals could improve cognitive function and cerebral hemodynamics in older adults. METHODS: Fifty participants aged 65 y or older were randomly assigned to either a 1-mo intervention group, which used a wearable device to monitor and increase chewing strokes during meals, or a control group that maintained usual chewing habits. Chewing behavior, cognitive performance (including memory and executive function via the color Stroop test), and cerebral hemodynamics in the dorsolateral prefrontal cortex (DLPFC) were measured at baseline and after 1 mo. Statistical analyses included t tests, chi-square tests, 2-way analysis of variance with post hoc tests, Pearson correlations, and generalized linear models to evaluate group differences and associations between chewing and cognitive outcomes. RESULTS: Significant time-by-group interactions were observed for memory, F(1, 48) = 6.24, P = 0.043, and hemodynamic responses in the left DLPFC, F(1, 48) = 6.19, P = 0.013. The intervention group showed increased chewing frequency (P = 0.017), improved memory performance, and reduced left DLPFC responses compared with controls. Chewing frequency was positively correlated with Stroop test scores (r = 0.53, P = 0.010) and negatively with hemodynamic changes in the left DLPFC (r = -0.30, P = 0.040). Although improvements in other cognitive outcomes and hemodynamic measures favored the intervention group, these differences did not reach statistical significance. CONCLUSIONS: Promoting intentional chewing habits for 1 mo may enhance memory-related cognitive performance and neural efficiency in the DLPFC during working memory tasks in older adults. This nonpharmacologic, low-burden strategy warrants further research with longer interventions to support cognitive health and dementia prevention. TRIAL REGISTRATION ID: UMIN000044280Knowledge Transfer Statement:This study demonstrates that promoting thorough chewing habits in older adults can improve memory and enhance neural efficiency in the brain. Encouraging intentional mastication is a simple, nonpharmacologic approach that may help maintain cognitive health and prevent dementia, providing a practical strategy for clinicians and policymakers to support healthy aging.

Humans↗

PubMed2026

Multi-Omics Genome-Wide to Explore the Formation and Development Targets for Intracranial Aneurysms.

Intracranial aneurysms (IAs) represent a significant and potentially life-threatening category of disease, and there is currently a lack of effective treatment options aimed at preventing the progression of the disease. Accordingly, this study is dedicated to exploring and identifying effective drug targets that can help in the prevention of both the formation and rupture of IAs, along with a detailed examination of the underlying potential mechanisms involved in these processes. The data related to IAs for this research was obtained from the ISGC Biobank and UK Biobank. Then, we investigated the possible biological functions and unintended consequences of targeting the specific genes that were highlighted in IAs by using mediation analysis, virtual knockout experiments, and PW-MR studies. A total of 5 unique potential drug targets for IAs (FKTN, MAP3K1, PSMA4, SLC22A4, ADAM17), 4 unique potential drug targets for SAH (PSMA4, ADAM17, GPR160, SLC22A4), and 2 unique potential drug targets for UIA (SLC22A4, PRCP) were identified across brain or blood samples. Among the various candidates identified, SLC22A4 has emerged as a promising potential drug target, showing significant expression levels in both blood and brain tissues. Additionally, phenome-wide MR of SLC22A4 across 32 selected phenotypes did not identify statistically significant adverse associations after FDR correction. Virtual knockout (KO) experiments on SLC22A4 revealed that SLC22A4 KO disrupted 81 genes, all of which are involved in IAs-related pathways. Besides, we recognized BRD-K85337334 as potential candidates for targeting SLC22A4. This research indicates that an increase in SLC22A4 gene expression within the blood or brain is directly linked to a heightened risk of IAs rupture, which will aid in prioritizing the development of drugs for IAs.

Humans↗

PubMed2026

Disentangling oscillatory and aperiodic neural activity in autism: A spectral parameterization analysis of neurofeedback intervention.

BACKGROUND: Autism Spectrum Disorder (ASD) is characterized by atypical neural oscillations and heterogeneous alterations in excitation/inhibition (E/I) balance, the directionality of which varies across individuals, neural circuits, and developmental stages. While Alpha-band neurofeedback (NFB) is a promising intervention, its underlying neurophysiological mechanisms remain unclear, partly due to the conflation of periodic and aperiodic signals in traditional EEG analysis. METHODS: This randomized controlled trial recruited 40 children with ASD, assigned to either an experimental group (Alpha-training NFB) or a no-feedback group. Resting-state EEG and behavioral assessments (SRS, ABC) were collected pre- and post-intervention. We employed spectral parameterization to decompose neural activity into aperiodic (1/f slope, offset) and periodic (periodic alpha power, center frequency) components. RESULTS: NFB training yielded significant behavioral improvements in social cognition and relating skills. Physiologically, the experimental group exhibited a significant steepening of the aperiodic slope (increased exponent), reflecting a reduction in neural noise and potential optimization of inhibitory modulation. Furthermore, we observed enhanced periodic alpha power and an acceleration of the alpha center frequency (ACF), indicative of improved neural efficiency and maturation. These physiological shifts in frontal and occipital regions were significantly correlated with improvements in behavioral scores. CONCLUSION: Alpha-training NFB was associated with improvements in caregiver-rated behavioral scores and modulated spectral features of resting-state EEG in children with ASD. These findings validate the utility of spectral parameterization markers in evaluating neuromodulatory interventions.

Humans↗

PubMed2026

Migration intentions among nigerian neurosurgeons: a national survey of workforce retention.

Physician emigration from low- and middle-income countries creates critical workforce shortages. This study explored factors influencing migration intentions among Nigerian neurosurgeons and trainees. We conducted an anonymized survey of consultant neurosurgeons, fellows, and residents practicing in Nigeria. Invitations were sent by email and professional messaging platforms, and snowball sampling was used to increase participation. The survey included quantitative and open-ended questions on demographics, income, migration plans, and retention factors. Seventy-nine respondents participated (61.5 % consultants; 93.7 % male; median age: 44 years). Nearly all practiced general neurosurgery (97.3 %), and many also performed trauma (65.3 %) and spine (61.3 %) neurosurgery. Most (85.7 %) reported that their earnings were insufficient to support their families. Nearly 40 % were considering emigration, most often citing financial pressures (88.5 %) and poor working conditions (63.5 %) as push factors. By contrast, personal or family ties (63.0 %) and relocation costs (45.2 %) were cited as reasons to stay. Respondents identified higher salaries (58.1 %) and greater investment in the health sector (51.4 %) as key measures to improve retention. In univariable analyses, younger age, income insufficiency, income dissatisfaction, and feeling undervalued at work were associated with migration intention. Financial insecurity emerged as the dominant driver of migration intentions among Nigerian neurosurgeons. In addition to salary increases, sustained investment in healthcare infrastructure and workforce support is essential to improve retention. International partnerships may complement these efforts by building neurosurgical capacity and mitigating brain drain.

Humans↗

PubMed2026

Restrictive vs Liberal Transfusion Strategy in Traumatic Brain Injury: A Secondary Analysis of the TRAIN Trial.

IMPORTANCE: Anemia is a prevalent condition among patients with traumatic brain injury (TBI); however, the optimal hemoglobin (Hb) threshold to initiate red blood cell transfusion (RBCT) is not well defined. OBJECTIVE: To assess which of 2 different Hb thresholds for guiding RBCT in patients with anemia and TBI is associated with a more favorable neurological outcome. DESIGN, SETTING, AND PARTICIPANTS: This was a preplanned secondary analysis of the Transfusion Strategies in Acute Brain Injured Patients multicentric randomized clinical trial, conducted in 72 intensive care units across 22 countries between September 1, 2017, and December 31, 2022. Follow-up was completed June 30, 2023. Only patients with TBI were included in the present analysis, conducted from February to May 2025. INTERVENTIONS: Liberal (transfusion at Hb <9 g/dL [to convert to g/L, multiply by 10.0]) vs restrictive (transfusion at Hb <7 g/dL) RBCT strategy over a maximum of 28 days. MAIN OUTCOME AND MEASURES: The primary outcome was the occurrence of unfavorable neurological outcome, defined as a Glasgow Outcome Scale Extended score of 1 to 5 (overall range, 1-8, with higher scores indicating more favorable outcome) at 180 days. In addition, 14 prespecified serious adverse events, including infection and cerebral ischemia, were assessed. Data were analyzed using both the intention-to-treat and per-protocol principles. RESULTS: Of 486 patients who presented with TBI (mean [SD] age, 46.8 [17.6] years; 347 [71.4%] male), 475 were included in the primary outcome analysis: 236 were randomized to the liberal transfusion strategy group and 239 to the restrictive transfusion strategy group. Both groups had similar baseline characteristics. In total, 534 RBCTs were administered in the liberal transfusion strategy group, compared with 246 RBCTs in the restrictive group. At 180 days after randomization, 138 patients (58.5%) in the liberal group had unfavorable neurological outcome compared with 161 patients (67.4%) in the restrictive group (relative risk [RR], 0.86 [95% CI, 0.75-1.00]; P = .047; fragility index = 1). There were no significant differences in the occurrence of secondary outcomes (eg, 28-day mortality: 42 of 240 [17.5%] vs 51 of 244 [20.9%]; RR, 0.84 [95% CI, 0.58-1.21]; P = .34) or serious adverse events (eg, RR, 1.13 [95% CI, 0.88-1.43]; P = .34 for infection and RR, 0.87 [95% CI, 0.40-1.90]; P = .72 for cerebral ischemia). After adjustment for several confounders, being randomized to the liberal group was associated with a lower observed probability of unfavorable neurological outcome (odds ratio, 0.60 [95% CI, 0.38-0.94]; P = .03). CONCLUSIONS AND RELEVANCE: In this secondary analysis of a multicenter randomized clinical trial, a liberal RBCT strategy was associated with a lower risk than a restrictive RBCT strategy of unfavorable neurological outcome at 180 days among patients with TBI. These findings should be interpreted with caution in light of the inherent uncertainty of the estimate. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02968654.

Humans↗

PubMed2026

Co-Use of Some Substances Associated With Higher Doses in Adolescents: Findings From the Adolescent Brain Cognitive Development Study.

PURPOSE: Adolescence is a critical developmental period marked by heightened vulnerability to initiating substance use, with long-term implications for health and behavior. Nicotine, alcohol, and cannabis are the most commonly used substances among adolescents. Their use often co-occurs but few studies have described or quantified the patterns and doses of substance co-use in this vulnerable population. METHODS: We used data from six waves of the Adolescent Brain Cognitive Development study. Substance use was measured through a web-based timeline followback interview, and outcomes are operationalized into substance use quantity (in standard units), single use, and co-use (use of two substances on the same day) of alcohol, cannabis, and nicotine. Group differences of average dose in standard units between single use and co-use for each substance class were analyzed using linear mixed-effects modeling in years 4-6. RESULTS: The average dose of nicotine was significantly higher when co-used with alcohol (4.32; 95% confidence interval [CI]: 2.55-6.09; p < .001) or when co-used with cannabis (4.41; 95% CI: 2.76-6.05; p < .001) in year 6; nicotine trends were similar in years four and five. In year 6, the average dose of alcohol was higher when co-used with cannabis (1.87; 95% CI: 0.37-3.36; p = .004) or co-used with nicotine (1.64; 95% CI: 0.06-3.22; p = .03) compared to single use of alcohol. The average dose of cannabis was not significantly different when used singularly or co-used with either alcohol or nicotine in our study years. DISCUSSION: During adolescence, the co-use of substances (namely alcohol and nicotine) may lead to higher average doses compared to single-substance use.

Humans↗

PubMed2026

Dissociable neural mechanisms of cognitive enhancement through transcranial stimulation and behavioral training.

BACKGROUND: Transcranial direct current stimulation (tDCS) and adaptive working memory (WM) training are promising cognitive enhancement approaches; however, their neural mechanisms and potential synergies remain poorly understood. OBJECTIVE: We directly compared how tDCS and WM training modulate neural oscillations during WM performance and examined whether combining both interventions produces additive effects. METHODS: We randomized 112 healthy adults into four groups: control (sham tDCS + non-adaptive 1-back), tDCS-only (active tDCS + non-adaptive 1-back), training-only (sham tDCS + adaptive n-back training), or combined (active tDCS + adaptive training). Participants underwent five daily intervention sessions. We recorded high-density EEG during transfer n-back tasks at baseline, post-intervention, and one-week follow-up. RESULTS: All active interventions improved WM performance relative to the control group, with the combined group showing the largest gains (n-back accuracy: +15.6% vs. + 10.1% tDCS-only, +9.7% training-only, +0.7% control; all p < 0.001). Critically, tDCS selectively increased gamma-band (30-50 Hz) power in the frontal and parietal regions (cluster p = 0.018, d > 1.0), whereas WM training enhanced frontal theta-band (4-8 Hz) power and theta-gamma phase-amplitude coupling (both cluster p < 0.012, d > 0.85). The combined group exhibited both neural signatures. Brain-behavior correlations revealed dissociable relationships: gamma increases predicted n-back accuracy improvements (r = 0.61, p < 0.001), whereas theta enhancements correlated with operation span gains (r = 0.58, p = 0.002). CONCLUSIONS: tDCS and WM training enhance cognition through distinct yet complementary neural mechanisms: tDCS via gamma-mediated cortical excitability and WM training via theta-mediated cognitive control. These findings provide neurophysiological evidence for multimodal enhancement strategies that target parallel pathways within WM networks.

Humans↗

PubMed2026

An automated geometric modeling framework in GATE for the design and optimization of high-sensitivity converging-beam SPECT collimators.

Objective.The trade-off between detection sensitivity and spatial resolution is a fundamental challenge in designing organ-dedicated Single-photon emission computed tomography (SPECT) collimators. While converging-hole geometries offer a solution, their optimization is often hindered by the lack of flexible computational tools capable of modeling large-scale, non-parallel hole arrays. This study aims to develop an automated geometric modeling framework to facilitate the design and evaluation of complex converging- and diverging-hole collimators within standard Monte Carlo environments.Approach.We developed a specialized modeling framework by implementing custom C++ classes and a vector-based alignment algorithm within GATE. This platform enables automated, orientation-consistent construction of large-scale converging arrays not natively supported by standard implementations. A high-sensitivity pure cone-beam collimator (CBC) was designed using this framework. The evaluation used hot-rod, disc, and Jaszczak phantoms for physical characterization, while XCAT and dedicated brain models were employed for clinical tasks, including cardiac, brain perfusion, and DaTscan SPECT simulations.Main results.The CBC achieved a nearly fourfold sensitivity increase compared to a conventional low-energy high-resolution parallel-hole collimator at a 20 cm radius of rotation, while maintaining comparable spatial resolution. Despite a 52.3% field of view reduction, the CBC yielded a 2.2-fold noise reduction (CV: 11.7% vs 25.9%) and mitigated partial volume effects via geometric magnification. XCAT and brain phantom simulations confirmed enhanced anatomical definition and contrast recovery in cardiac, perfusion, and DaTscan tasks.Significance.This work provides an efficient computational tool for rapid design space exploration of advanced collimator geometries. The results demonstrate that the proposed CBC design offers a significant sensitivity advantage, making it highly suitable for high-performance, small-volume clinical applications such as brain and cardiac molecular imaging.

Tomography, Emission-Computed, Single-Photon↗

PubMed2026

Cognitive-metabolic relationship in temporal lobe epilepsy: A systematic review.

OBJECTIVE: To summarize the current literature on neurometabolic dysfunction identified through brain imaging and its cognitive correlates in temporal lobe epilepsy (TLE). BACKGROUND: Cognitive decline contributes to chronic disability in TLE. The pathophysiology of cognitive decline in TLE is poorly understood, limiting therapeutic advances. Characterizing metabolic changes in patients with TLE and cognitive impairment may identify biomarkers and inform new treatment strategies. DESIGN/METHODS: We conducted a systematic review of five major databases, gathering studies published through December 2024, in accordance with PRISMA guidelines. We included all observational studies describing associations between metabolic imaging findings and cognitive measures in TLE. RESULTS: Of 1449 reports, 38 met the inclusion criteria, encompassing 1161 patients with TLE aged 5-66 years. Twenty-two studies applied fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to assess interictal brain glucose metabolism. Two studies utilized PET with other tracers to assess more specific metabolic aspects. Fourteen studies used proton magnetic resonance spectroscopy (1H-MRS) to quantify local concentrations of brain metabolites. Impairment of verbal memory was consistently associated with left temporal lobe metabolite changes. Non-memory cognitive impairments correlated with changes in glucose metabolism, N-acetylaspartate, and gamma-aminobutyrate in both temporal and extratemporal areas. CONCLUSION: 18F-FDG PET remains the most widely used imaging modality to assess cognitive-metabolic correlates in TLE, while other PET tracers and 1H-MRS are potentially underexplored. Verbal memory impairment correlates robustly with left temporal dysmetabolism. Cognitive impairment in TLE is multifaceted and correlates with measurable changes in metabolism in both temporal and extratemporal regions. While our synthesis was restricted by some methodological limitations, these neurometabolic signatures may hold promise as potential biomarkers for identifying risk of cognitive decline and highlight avenues for future research.

Humans↗

PubMed2026

Genetic evidence for a causal relationship between melatonin metabolism and depression.

To investigate the causal relevance of melatonin metabolism, which provides the biological basis for circulating melatonin levels, to specific depression symptom subtypes, we performed a targeted systematic review of melatonin metabolism pathways in the human brain and liver. Using two-sample Mendelian randomization (MR), we assessed the causal effects of metabolism pathways and/or individual genes on major depressive disorder (MDD) and nine symptom subtypes derived from Patient Health Questionnaire-9 (PHQ-9). Instrumental variables (IVs) were expression quantitative trait loci (eQTL) for eight individual genes, one synthesis route, and three degradation routes. Results were assessed using Bayesian colocalization and phenome-wide association analyses. At the pathway-level, the genetically proxied synthesis-route signal was associated with PHQ-9 Assessment 5 (PHQ9A5, OR: 0.89, 95% CI: 0.85-0.93), but sensitivity analyses suggested this association was primarily driven by TPH1 and may reflect serotonin-related biology. In contrast, higher brain melatonin degradation raised the risk of both PHQ9A1 (OR: 1.03, 95% CI: 1.02-1.04) and PHQ9A7 (OR: 1.03, 95% CI: 1.02-1.03). Within degradation, up-regulation of the kynurenine sub-pathway increased the odds of PHQ9A3 (OR: 1.05, 95% CI: 1.02-1.07), PHQ9A4 (OR = 1.04, 95% CI: 1.02-1.06) and PHQ9A7 (OR: 1.05, 95% CI: 1.02-1.07). Gene-level analyses were largely concordant, except for SULT1A1, whose higher expression was genetically protective for PHQ9A3 but risk-increased for PHQ9A1 and PHQ9A4. Overall, these results demonstrate that melatonin metabolism exerts symptom-specific and pathway-specific causal effects on depression. A stratified view of melatonin's role may help optimize the application of exogenous melatonin supplementation.

Melatonin↗

PubMed2026

Does high fructose consumption trigger microglia activation and neuroinflammation? A systematic review.

This systematic review evaluated the effects of fructose intake on neuroinflammatory markers in rodent models. The search terms Fructose AND neuroinflammation OR Neurodegeneration OR chemokines OR interleukins OR microglia OR behaviour OR memory OR cognition were used in Google Scholar, Scopus and Web of Science. Thirteen animal studies investigating fructose-induced neuroinflammation that matched the eligibility criteria were included in the study. Across the studies, 16 inflammatory markers were identified and significantly altered following exposure to fructose. The findings consistently demonstrated elevated expression of pro-inflammatory cytokines, TNF-α, IL-6, and IL-1β, following fructose administration. Fructose consumption also dysregulated MCP-1, fractalkine, and CX3CR1 levels, thereby promoting inflammatory signalling and microglial activation. Furthermore, fructose exposure significantly increased IBA-1 and CD11b, indicating sustained neuroimmune activation. Alterations in important inflammatory pathways involving TLR4, NLRP3, NF-κB, MyD88, iNOS, and cyclooxygenases (COX-1 and COX-2) were also observed. In contrast, expression of the anti-inflammatory regulator peroxisome proliferator-activated receptor gamma (PPARγ) was reduced after fructose treatment. Overall, the findings suggest that chronic fructose consumption induces neuroinflammation through multiple inflammatory and immune-related mechanisms in the brain. These effects appear to be dose- and duration-dependent and may contribute significantly to neurodegeneration and cognitive impairment.

Microglia↗

PubMed2026

Neuroimaging anxious children and adolescents before and after cognitive behavioral therapy: a systematic review.

OBJECTIVE: This systematic review investigates brain changes in youths with anxiety disorders following cognitive behavioral therapy (CBT) and neural markers that predict CBT responses. METHODS: We conducted a systematic search using the electronic databases PubMed, Web of Science, and ProQuest. The inclusion deadline was set to October 27, 2025. We included fifteen peer-reviewed neuroimaging studies that examined the effects of CBT in youths under 19 years old with a primary clinical diagnosis of an anxiety disorder based on DSM-5 criteria. RESULTS: Although the existing literature is marked by substantial diversity in methods and outcomes, task-related neural response in the anterior cingulate cortex (ACC, 2/8, 25.0%), insula (1/8, 12.5%) increased from pre to post CBT and these changes were further correlated with clinical symptom improvements. Moreover, CBT outcomes were predicted by pre-treatment activity or connectivity in the ACC and amygdala (3/13, 23.0%). A smaller proportion of studies (2/13, 15.3%) found that activity or connectivity in the insula, precuneus/cuneus, postcentral gyrus, and activity or structure in the nucleus accumbens (NAcc) predicted response to CBT. The low consistency of these findings was driven by methodological variability, low reliability of the neural markers, and relatively small sample sizes. CONCLUSIONS: This review highlights promises of neural predictors and outcomes to enhance anxiety disorder treatments in children and adolescents, facilitating future personalized and effective CBT. Beyond this initial promise, the field is hindered by methodological inconsistencies and limited replications. While longitudinal and personalized approaches are important next steps, the central challenge remains: identifying neural markers that are both reliable and robust.

Adolescent↗

PubMed2026

Dissociating behavioral, neural and experiential effects of prefrontal HD-tDCS during conflict resolution.

Inconsistent evidence regarding the cognitive effects of transcranial direct current stimulation (tDCS) highlights the need for more comprehensive approaches to assess its impact. This study aimed to investigate the effects of high-definition tDCS (HD-tDCS) on conflict resolution by combining behavioral, neural, and subjective experience measures. Sixty participants were randomly assigned to anodal, cathodal, or sham HD-tDCS groups and completed a 30-min flanker task. EEG was recorded during the first and last blocks (without stimulation), while stimulation was applied during the intermediate blocks of the task. Using a multidimensional methodological approach including Drift-Diffusion Modeling (DDM), EEG spectral analysis, Lempel-Ziv complexity, and Temporal Experience Tracing (TET), we assessed the cognitive, neural, and phenomenological effects of stimulation. Behavioral results indicated no significant improvements in reaction times or accuracy across the stimulation groups. Similarly, DDM parameters showed no effect of HD-tDCS on latent cognitive processes. However, EEG data revealed a significant reduction in neural complexity in the anodal group during resting-state, suggesting a stabilization or reorganization of neural dynamics. Subjective experience analysis identified two distinct clusters of task-related feelings, though time spent in these experiential states did not differ between groups. Interestingly, sensation of stimulation was significantly higher for anodal stimulation than sham when analyzed as a single dimension. Despite null behavioral effects, this study provides important insights into the neural and subjective responses to HD-tDCS and highlights the value of integrating complementary multidimensional approaches to better characterize brain stimulation effects. These findings contribute to the ongoing debate about the efficacy of tDCS in cognitive enhancement.

Humans↗