Brain Integrity Research Articles

Association between physical function and neuroimaging measures in a 2‐year multidomain lifestyle randomized controlled trial

AbstractBackgroundThis exploratory study investigated associations between physical function and neuroimaging biomarkers: brain magnetic resonance imaging (MRI) and Pittsburgh compound B‐positron emission tomography (PiB‐PET) measures during the 2‐year Finnish Geriatric Intervention Study to prevent cognitive impairment and disability (FINGER).MethodFINGER targeted 60–77‐year‐old general population at‐risk and without dementia or substantial cognitive impairment. Measures of physical function (activities of daily living (ADL), hand grip strength, physical performance, Fried’s frailty phenotype index and self‐rated health) from baseline and 2‐year visits were used. Baseline neuroimaging measures, MRI (hippocampus, total gray matter volumes, Alzheimer’s disease (AD) signature cortical thickness) were available for 115‐132 participants and PiB‐PET (composite score) for 44‐48 participants. Linear and logistic regressions were used to test the cross‐sectional associations and the impact of baseline imaging measures on changes in physical function. Models were adjusted for site, sex and education.ResultCross‐sectionally, higher ADL were associated with higher hippocampus volume (ß = 0.18 p = 0.048), total gray matter volume (ß = 0.15 p = 0.005) and AD signature cortical thickness (ß = 0.25 p = 0.006) while stronger hand grip and was associated with higher total gray matter volume (ß = 0.20 p = 0.041) significantly. Baseline imaging measures were associated with changes in physical function: higher baseline hippocampus volume was associated with maintenance/improvement in the ADL (OR = 0.56 p = 0.039) while lower hippocampus at baseline predicted poorer physical performance over time (OR = 1.66 p = 0.036).ConclusionHigher brain integrity is associated with better physical function while lower baseline brain integrity predicts poorer physical function over time.

Discovery of disease‐associated, tau, and inflammatory microglial subpopulations and molecular drivers in Alzheimer’s disease using network‐based deep learning integration of human brain single‐cell RNA‐sequencing data

AbstractBackgroundMicroglia have been implicated in the pathophysiology of Alzheimer’s disease (AD) for over 100 years, and substantial progress has been made in characterizing microglial heterogeneities and biology, including disease‐associated microglia (or DAM, amyloid‐pathology related, neuro‐protective), tau microglia (tau‐pathology related), and inflammatory microglia (neuro‐toxic). However, the crucial next step knowing how to apply these findings to develop new treatments for AD, through uncovering the functional roles and molecular drivers of each microglial subtype, has not yet been accomplished.MethodIn this study, we conducted single‐cell RNA‐sequencing data integration analyses of ∼0.8 million cells/nuclei by leveraging frozen brain samples from AD subjects across different brain regions from The Alzheimer’s Cell Atlas (https://taca.lerner.ccf.org/) using a deep learning analytic approach. We annotated three microglial subtypes (including DAM, tau, and inflammatory microglia) using well‐established marker genes and then used a human protein‐protein interactome network‐based approach to identify potential molecular drivers of different microglial subtypes across the spectrum of AD. We also applied transition gene network analysis to characterize microglial subtype transition from non‐disease associated to disease‐associated stages at transcriptomic levels.ResultVia trajectory analysis we pinpointed the existence of three microglial subtypes across AD progression. We also identified that tau microglia were significantly associated with synaptic processes. Compared to DAM, upregulated genes within inflammatory microglia were more significantly enriched within key immune pathways (e.g., NF‐kappa B and toll‐like receptor signaling pathways). In addition, transition gene networks of inflammatory microglia and DAM were found to contain potential AD pathobiology regulators (e.g., SYK, LYN, IRF8, and CSF1R) and genetic risk genes (including INPP5D, PICALM, and MEF2A). We further conducted network‐based drug repurposing prediction by simultaneously activating DAM while inhibiting inflammatory microglia, which indicated that several predicted repurposable drugs (i.e., fluticasone and mometasone) are significantly associated with reduced risk of AD in large patient databases.ConclusionThis study identifies potential underlying mechanisms of microglial subtypes involved in human AD brains, leading to potential drug targets for future development of microglia‐targeted therapies for AD.

Alzheimer Plasma Biomarkers Distinguish SuperAgers from their Cognitively Average Peers

AbstractBackgroundSuperAgers are individuals ≥80 years old who were selected for having episodic memory performance that is at least as good as individuals 20‐30 years their junior. We have previously shown that on average SuperAgers show lower neurofibrillary tangle density in the entorhinal cortex than cognitively average controls, which may be one biological factor contributing to superior memory beyond the 8th decade. This preliminary study investigated whether plasma concentrations of Alzheimer and related neurodegenerative biomarkers differ between SuperAgers and their cognitively average peers.MethodSuperAgers (N = 61) and Cognitively Average Controls (N = 28) were enrolled through the SuperAging Research Program. The plasma biomarkers amyloid β peptide 40 (Aβ40), amyloid β peptide 42 (Aβ42), neurofilament light (NFL), phosphorylated tau‐181 (pTau‐181), and glial fibrillary acidic protein (GFAP) were measured in SuperAgers and Cognitively Average participants using the Quanterix single molecule protein detection (SIMOA) platform. Independent samples t‐tests were used for statistical analyses (significance was set at p<0.05, uncorrected).ResultThere were no significant differences in mean age between SuperAgers and Cognitively Average Controls. Concentrations of Aβ42, Aβ40, the ratio of Aβ42/Aβ40, NFL or GFAP did not significantly differ between groups. On average, SuperAgers and Controls showed pTau‐181 levels that were <16.5 pg/mL, falling within the “Unlikely Alzheimer’s” designation according to Quanterix guidelines. SuperAgers showed significantly lower pTau‐181 levels compared to Cognitively Average Controls [M = 5.42 pg/mL (SD = 2.60) vs M = 7.10 pg/mL (SD = 3.14), respectively].ConclusionPlasma phosphotau biomarkers are promising for the assessment of brain integrity versus degeneration across the age‐Alzheimer continuum. The current results provide preliminary support for the contention that the SuperAger brain may be even more removed from the Alzheimer side of the continuum than neurotypical controls.Emily Rogalski and Changiz Geula contributed equally to this study.

Common neurobiological mechanisms underlying anosognosia and neuropsychiatric symptoms across the Alzheimer’s disease spectrum

AbstractBackgroundBoth loss of awareness for cognitive decline (a.k.a. anosognosia) and neuropsychiatric symptoms (NPS) are common symptoms in Alzheimer’s disease (AD) and have been associated with AD pathology. Recent studies have shown a co‐occurrence between these symptoms across the AD spectrum, suggesting shared underlying neurophysiological processes, especially within the default mode network (DMN). Here, we investigated the relationship between NPS and altered awareness and the structural integrity (as assessed with diffusion tensor imaging, DTI) of brain regions supporting the DMN in participants with and without amyloid pathology.MethodsThree‐hundred participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) underwent an amyloid positron emission tomography (PET), using 18F‐AV45 (florbetapir), and were classified into two groups: amyloid‐positive (A+) and negative (A‐). Individual mean fractional anisotropy (FA) was calculated from tracts overlapping the DMN regions. An awareness index was computed using the discrepancy between Everyday Cognition questionnaire scores from participants and informants. The Neuropsychiatric Inventory Total Score was used to assess the informant‐reported NPS. We compared amyloid groups on demographics and our different measures of interest. Pearson correlations were used to determine associations between measures of interest in each amyloid group. A multivariate multiple regression (MMR) model was performed to determine whether structural brain integrity predicts altered awareness and NPS jointly.ResultsA+ participants were significantly older (74 ± 7 vs. 72 ± 7 for A‐), more impaired (CDR global), and showed lower awareness and diffusion, and greater NPS (all p<0.001, see Table 1). Significant correlations were found between the FA, NPS, and awareness measures in A+ participants, with decreased FA associated with decreased awareness and more NPS. The MMR confirmed these associations between FA, awareness and NPS (p<0.02, see Table 2). The Pillai test revealed that the DTI effect jointly contributed to both models. No significant relationships were observed in the A‐ group.ConclusionOur results show that, in amyloid‐positive individuals across the AD spectrum, decreased awareness and increased NPS were related to decreased structural integrity of the DMN. This supports the hypothesis of common neurobiological mechanisms underlying anosognosia and NPS in AD.

Rôle de l’axe microbiote-intestin-cerveau dans la dérégulation du comportement alimentaire au cours de l’obésité et de l’hyperphagie boulimique : les mécanismes: Implication of the microbiota-gut-brain axis in the changes of eating behavior in obesity and binge eating disorder (BED): the mecanisms

Eating disorders (ED), particularly compulsive ED such as binge eating disorder (BED), play an important role in the pathophysiology of obesity. Recent data have highlighted the involvement of the microbiotagut-brain axis in the regulation of eating behavior; its deregulation could therefore contribute to the onset of obesity via the development or perpetuation of ED, in particular BED. This review highlights the various peripheral and central pathophysiological mechanisms linking intestinal dysbiosis and the disruption of eating behavior leading to obesity and BED. The main peripheral regulatory signals involved are peptides associated with food intake (ghrelin, GLP-1), short-chain fatty acids and bacterial components. The brain integration of peripheral and central signals modulating food intake, involving at homeostatic (arcuate nucleus of the hypothalamus) and hedonic (reward system) levels, will be described during BED and obesity. This better understanding of the role of the microbiota-gut-brain axis in the control of eating behavior in relation to the pathophysiology of obesity opens up prospects for innovative therapeutic strategies targeting gut microbiota reshaping.© 2023 Société francophone nutrition clinique et métabolisme (SFNCM).Published by Elsevier Masson SAS. All rights reserved.

Mechanisms linking proteins and structural brain integrity to biological markers of Alzheimer’s Disease

AbstractBackgroundMedial temporal lobe (MTL) networks, including posterior‐medial (PM) and anterior‐temporal (AT) subnetworks, are early affected by Alzheimer’s disease (AD) pathologies (tau, neurodegeneration) and are critical for memory, which declines in AD. The biological pathways linking AD pathology, changes in MTL‐AT‐PM structural connectivity (SC), and cognitive decline, are unknown. Plasma protein levels reflect those in the cerebrospinal fluid, providing a low‐invasive potential means of understanding molecular brain changes that occur in AD. These measures may help explain how AD pathology, MTL‐AT‐PM SC, and cognitive decline are linked at the molecular level. We used predefined aging‐related plasma proteins from a meta‐analysis to explore links between MTL‐AT‐PM SC, AD pathologies, and cognitive decline.MethodMTL‐AT‐PM SC scores and plasma protein levels from 100 participants (Stanford ADRC: mean age = 73.7y, 82 healthy control, 16 mild cognitive impairment, and 2 AD) were entered into an Coupled tensor and matrix factorization algorithm, generating clusters based on shared SC‐protein variance. Linear regression analyses were conducted to evaluate cluster relationships with domains of AD (memory, plasma tau, and neurodegeneration by plasma NfL and cortical thickness index).ResultTwo (out of 12 total) SC‐protein clusters significantly related to both tau and neurodegeneration. Both had similar highly contributing proteins (TNFRSF1B.3152.57.1, TNFRSF1B.8368.102.3, GRN.4992.49.1, TNC.4155.3.2, RPS3A.5484.63.3, CD163.5028.59.1, EFNA4.2614.28.2) and SC regions (bilateral: hippocampus, and left: parahippocampal cortex, precuneus, thalamus, and isthmus cingulate). Hippocampal laterality (bilateral vs. opposite directions for left vs. right) and the direction of their relationship to tau/neurodegeneration differentiated these clusters. A 3rd cluster was uniquely associated with composite memory (SC: bilateral: lateral occipital and parahippocampus, left: inferior temporal and hippocampus; proteins: EGFR.2677.1.1, SFRP1.3221.54.1, FAS.9459.7.3, ERBB3.2617.56.35, CFD.13678.169.3, LRP1.8601.167.3, and LPO.4801.13.3).ConclusionProtein‐SC clusters showed both overlapping and unique associations to AD‐associated memory, tau, and neurodegeneration. Two clusters centered on the hippocampus and proteins related to inflammation showed relationships to both tau and neurodegeneration, suggesting they may be important for linking these two aspects of AD pathology. A memory‐related cluster was dominated by neurogenesis related proteins, and occipital/parahippocampal cortex. These findings suggest molecular pathways may differentially affect the left vs. right hippocampus, and AD‐associated pathologies vs. cognition.

Sleep Patterns and Prospective Diffusion Weighted Imaging Biomarkers: the Sleep and Dementia Consortium (SDC)

AbstractBackgroundAdequate sleep is necessary to maintain brain health, with sleep disturbances associated with higher Alzheimer’s disease (AD) risk. Diffusion‐weighted imaging (DWI) metrics are increasingly recognized as useful neuroimaging biomarkers to detect AD‐related white matter degeneration. We assessed the relationship between sleep patterns and prospective DWI metrics in the Sleep and Dementia Consortium (SDC). The SDC studies associations between polysomnography (PSG)‐derived sleep with dementia risk and cognitive and MRI endophenotypes.MethodThe SDC includes five community‐based cohorts, two of which have DWI acquisitions: The Framingham Heart Study (FHS) and the Atherosclerosis Risk in Communities study (ARIC). Dementia‐free participants who underwent both PSG and DWI‐MRI were selected, including 354 FHS participants (56.6±7.1y, 57%W), and 184 ARIC participants (61.6±5.0y, 52%W). The MRI session was approximately 15 years after the PSG on average (FHS:17.0±1.3y; ARIC:15.8±0.8y). Fractional anisotropy (FA) and mean diffusivity (MD) were considered for both cohorts, in addition to free‐water (FW) in the FHS. Sleep metrics were harmonized centrally, distributed for cohort‐specific linear regressions, and study‐level estimates were pooled in random effects meta‐analyses. Analyses were adjusted for demographics, obesity, time between PSG and MRI, antidepressants and sedative medication usage. An interaction term by APOE4 allele carrier status in regression models was used to test its moderating effect.ResultIn the FHS, sleep fragmentation was associated with DWI measures in the expected direction: Higher Wake After Sleep Onset and lower Sleep Maintenance Efficiency were associated with lower FA (β±SE = ‐0.17±0.09,p = 0.04; β±SE = 0.23±0.10,p = 0.03), higher MD (β±SE = 0.15±0.07,p = 0.04; β±SE = ‐0.20±0.09,p = 0.03), and higher FW (β±SE = 0.17±0.07,p = 0.02; β±SE = ‐0.22±0.08,p = 0.008). Meta‐analysis of FHS and ARIC revealed significant pooled effects between lower Sleep Maintenance Efficiency and lower FA (β±SE = 0.17±0.08,p = 0.04). In the FHS, APOE4 allele significantly moderated the association between REM sleep proportion with FA and MD, where lower REM sleep percentage was associated with higher MD (β±SE = ‐4.89±1.95,p = 0.02) and lower FA (β±SE = 4.93±2.26,p = 0.03) in APOE4 carriers only.ConclusionIn the SDC, sleep fragmentation was associated with MRI markers of poorer white matter integrity 15 years later. Less REM sleep was associated with poorer white matter integrity in APOE4 allele carriers only, suggesting that disrupted sleep architecture may contribute and interact with neurodegenerative processes to affect brain integrity.

Brain Endothelial Cells as Potential Therapeutic Targets in Neurological Diseases

Brain homeostasis highly depends on Blood Brain Barrier (BBB) function and integrity. BBB displays some changes as individuals age, and brain endothelium damage has a key role in the pathology of neurological diseases such as ischemic stroke and neurodegenerative disorders

Neural correlates of cross-alphabetic interference and integration in the biliterate brain

Neural correlates of cross-alphabetic interference and integration in the biliterate brain

Lipophorin receptors genetically modulate neurodegeneration caused by reduction of Psn expression in the aging Drosophila brain.

Mutations in the Presenilin (PSEN) genes are the most common cause of early-onset familial Alzheimer's disease (FAD). Studies in cell culture, in vitro biochemical systems, and knockin mice showed that PSEN mutations are loss-of-function mutations, impairing γ-secretase activity. Mouse genetic analysis highlighted the importance of Presenilin (PS) in learning and memory, synaptic plasticity and neurotransmitter release, and neuronal survival, and Drosophila studies further demonstrated an evolutionarily conserved role of PS in neuronal survival during aging. However, molecular pathways that interact with PS in neuronal survival remain unclear. To identify genetic modifiers that modulate PS-dependent neuronal survival, we developed a new DrosophilaPsn model that exhibits age-dependent neurodegeneration and increases of apoptosis. Following a bioinformatic analysis, we tested top ranked candidate genes by selective knockdown (KD) of each gene in neurons using two independent RNAi lines in Psn KD models. Interestingly, 4 of the 9 genes enhancing neurodegeneration in Psn KD flies are involved in lipid transport and metabolism. Specifically, neuron-specific KD of lipophorin receptors, lpr1 and lpr2, dramatically worsens neurodegeneration in Psn KD flies, and overexpression of lpr1 or lpr2 does not alleviate Psn KD-induced neurodegeneration. Furthermore, lpr1 or lpr2 KD alone also leads to neurodegeneration, increased apoptosis, climbing defects, and shortened lifespan. Lastly, heterozygotic deletions of lpr1 and lpr2 or homozygotic deletions of lpr1 or lpr2 similarly lead to age-dependent neurodegeneration and further exacerbate neurodegeneration in Psn KD flies. These findings show that LpRs modulate Psn-dependent neuronal survival and are critically important for neuronal integrity in the aging brain.

Interfering TRIB3 protects the blood brain barrier through PI3K/Akt pathway to alleviate cerebral ischemia-reperfusion injury in diabetes mellitus mice

This study aimed to treat diabetic cerebral ischemia-reperfusion injury (CI/RI) by affecting blood brain barrier (BBB) permeability and integrity. The CI/RI model in DM mice and a high glucose (HG) treated oxygen and glucose deprivation/reoxygenation (OGD/R) brain endothelial cell model were established for the study. Evans blue (EB) staining was used to evaluate the permeability of BBB in vivo. TTC staining was used to analyze cerebral infarction. The location and expression of tribbles homolog 3 (TRIB3) in endothelial cells were detected by immunofluorescence. Western blotting was used to detect the protein expressions of TRIB3, tight junction molecules, adhesion molecules, phosphorylated protein kinase B (p-AKT) and AKT. The levels of pro-inflammatory cytokines were detected by qRT-PCR. Trans-epithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran were used to measure vascular permeability in vitro. TRIB3 ubiquitination and acetylation levels were detected. Acetyltransferase bound to TRIB3 were identified by immunoprecipitation. TRIB3 was localized in cerebral endothelial cells and was highly expressed in diabetic CI/R mice. The BBB permeability in diabetic CI/R mice and HG-treated OGD/R cells was increased, while the junction integrity was decreased. Interference with TRIB3 in vitro reduces BBB permeability and increases junction integrity. In vivo interfering with TRIB3 reduced cerebral infarction volume, BBB permeability and inflammation levels, and upregulated p-AKT levels. The phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin reversed the effects of TRIB3-interfering plasmid. In vitro HG treatment induced TRIB3 acetylation through acetyltransferase p300, which in turn reduced ubiquitination and stabilized TRIB3. Interfering TRIB3 protects BBB by activating PI3K/AKT pathway and alleviates brain injury, which provides a new target for diabetic CI/RI.

Cerebrovascular Function is Altered in Hemodialysis Patients.

Hemodialysis (HD) patients have declines in cerebral blood flow (CBF) and cerebral oxygenation during HD that may lead to ischemic brain injury. Cerebrovascular reactivity (CVR) may indicate which individuals are more susceptible to intradialytic hypoperfusion and ischemia. We hypothesized that HD patients would have decreased CVR and increased CBF relative to controls and deficits in CVR would be related to brain structural deficits. We measured cortical thickness and white matter hyperintensity (WMH) volume from T1 and T2 FLAIR images respectively, CVR from a breath hold BOLD CVR fMRI and arterial transit time (ATT) and CBF from ASL. Cerebrovascular and structural deficits in gray and white matter (GM and WM) were tested by averaging across the tissue and with a pothole analysis. Finally, we correlated cortical thickness and WMH volume with GM and WM cerebrovascular variables to assess the relationship between brain structure and cerebrovascular health. In ten HD patients, cortical thickness was found to be decreased (p= 0.002), WMH volume increased (p=0.004), and WM CBF increased (p=0.02) relative to ten controls. Pothole analysis indicated a higher number of increased GM and WM CBF voxels (p=0.03, p=0.02) and a higher number of decreased GM and WM CVR voxels (p=0.02, p=0.01). This pilot study demonstrates that HD patients have decreased CVR and increased CBF relative to controls, along with reduced brain integrity. Further investigation is required to fully understand if these cerebrovascular deficits may lead to structural changes.

11 Contributions of Cardiovascular Burden, Peripheral Inflammation, and Brain Integrity on Digital Clock Drawing Performance in Non-Demented Older Adults

Objective:Higher cardiovascular burden and peripheral inflammation are associated with small vessel vascular disease, a predominantly dysexecutive cognitive profile, and a higher likelihood of conversion to vascular dementia. The digital clock drawing test, a digitized version of a standard neuropsychological tool, is useful in identifying cognitive dysfunction related to vascular etiology. However, little is known about the specific cognitive implications of vascular risk, peripheral inflammation, and varying levels of overall brain integrity. The current study aimed to examine the role of cardiovascular burden, peripheral inflammation, and brain integrity on digitally acquired clock drawing latency and graphomotor metrics in non-demented older adults.Participants and Methods:The final prospectively recruited IRB-consented participant sample included 184 non-demented older adults (age: 69±6 years, education: 16±3 years, 46% female, 94% white) who completed digital clock drawing, vascular assessment, blood draw, and brain MRI. Digital clock drawing variables of interest included: total completion time (TCT), pre-first hand latency (PFHL), digit misplacement, hour hand distance from center, and clock face area (CFA). Cardiovascular burden was calculated using the revised version of the Framingham Stroke Risk Profile (FSRP-10). Peripheral inflammation was operationalized using interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-a), and high sensitivity C-reactive protein (hsCRP). The brain integrity composite was comprised of bilateral entorhinal cortex volume, bilateral ventricular volume, and whole brain leukoaraiosis.Results:Over and above age and cognitive reserve, hierarchical regressions showed FSRP-10, inflammatory markers, and brain integrity explained an additional 13.3% of the variance in command TCT (p< 0.001), with FSRP-10 (p=0.001), IL-10 (p= 0.019), and hsCRP (p= 0.019) as the main predictors in the model. FSRP-10, inflammatory markers, and brain integrity explained an additional 11.7% of the variance in command digit misplacement (p= 0.009), with findings largely driven by FSRP-10 (p< 0.001).Conclusions:Overall, in non-demented older adults, subtle behavioral nuances seen in digital clock drawing metrics (i.e., total completion time and digit misplacement) are partly explained by cardiovascular burden, peripheral inflammation, and brain integrity over and above age and cognitive reserve. These nuanced behaviors on digitally acquired clock drawing may associate with an emergent disease process or overall vulnerability.Funding sources: Barber Fellowship; K07AG066813; R01 AG055337; R01 NR014810; American Psychological Foundation Dissertation Award; APA Dissertation Research Award

Alterations of dynamic and static brain functional activities and integration in stroke patients

ObjectiveThe study aimed to investigate the comprehensive characteristics of brain functional activity and integration in patients with subcortical stroke using dynamic and static analysis methods and to examine whether alterations in brain functional activity and integration were associated with clinical symptoms of patients.MethodsDynamic amplitude of low-frequency fluctuation (dALFF), static amplitude of low-frequency fluctuation (sALFF), dynamic degree centrality (dDC), and static degree centrality (sDC) were calculated for 19 patients with right subcortical stroke, 16 patients with left subcortical stroke, and 25 healthy controls (HC). Furthermore, correlation analysis was performed to investigate the relationships between changes in brain functional measurements of patients and clinical variables.ResultsGroup comparison results showed that significantly decreased dALFF in the left angular (ANG_L) and right inferior parietal gyrus (IPG_R), decreased sALFF in the left precuneus (PCUN_L), and decreased sDC in the left crus II of cerebellar hemisphere (CERCRU2_L) and IPG_R, while significantly increased sDC in the right lobule X of cerebellar hemisphere (CER10_R) were detected in patients with right subcortical stroke relative to HC. Patients with left subcortical stroke showed significantly decreased sALFF in the left precuneus (PCUN_L) but increased sDC in the right hippocampus (HIP_R) compared with HC. Additionally, the altered sDC values in the CER10_R of patients with right subcortical stroke and in the HIP_R of patients with left subcortical stroke were associated with the severity of stroke and lower extremities motor function. A correlation was also found between the altered sALFF values in the PCUN_L of patients with left subcortical stroke and lower extremities motor function.ConclusionThese findings suggest that time-varying brain activity analysis may supply complementary information for static brain activity analysis. Dynamic and static brain functional activity and integration analysis may contribute to a more comprehensive understanding of the underlying neuropathology of dysfunction in stroke patients.

Astrogliosis in multiple sclerosis and neuro-inflammation: what role for the notch pathway?

Multiple sclerosis is an autoimmune inflammatory disease of the central nervous system leading to neurodegeneration. It affects 2.3 million people worldwide, generally younger than 50. There is no known cure for the disease, and current treatment options - mainly immunotherapies to limit disease progression - are few and associated with serious side effects. In multiple sclerosis, disruption of the blood-brain barrier is an early event in the pathogenesis of lesions, predisposing to edema, excito-toxicity and inflammatory infiltration into the central nervous system. Recently, the vision of the blood brain barrier structure and integrity has changed and include contributions from all components of the neurovascular unit, among which astrocytes. During neuro-inflammation, astrocytes become reactive. They undergo morphological and molecular changes named "astrogliosis" driving the conversion from acute inflammatory injury to a chronic neurodegenerative state. Astrogliosis mechanisms are minimally explored despite their significance in regulating the autoimmune response during multiple sclerosis. Therefore, in this review, we take stock of the state of knowledge regarding astrogliosis in neuro-inflammation and highlight the central role of NOTCH signaling in the process of astrocyte reactivity. Indeed, a very detailed nomenclature published in nature neurosciences in 2021, listing all the reactive astrocyte markers fully identified in the literature, doesn't cover the NOTCH signaling. Hence, we discuss evidence supporting NOTCH1 receptor as a central regulator of astrogliosis in the pathophysiology of neuro-inflammation, notably multiple sclerosis, in human and experimental models.

P049 Actigraphic rest-activity rhythms in older adults ‘at risk’ for dementia: associations with reduced cortical thickness in frontal, temporal and occipital cortices

Abstract Background Rest-activity rhythm disturbance is common in older adults ‘at risk’ for dementia. This may be an early marker of underlying disease pathology and risk of future decline. However, our understanding of how rest-activity rhythm relates to brain integrity remains unclear. Methods This study used vertex-wise analyses to examine the association between nonparametric actigraphy measures and cortical thickness in older adults ‘at risk’ for dementia. Primary measures of interest were intra-daily variability (IV), relative amplitude (RA), inter-daily stability (IS), and average activity during the least active 5-hour period (L5). Results 143 older adults ‘at risk’ for cognitive decline were included (mean age=67.41, SD=7.96). Higher IV was associated with lower cortical thickness in the right cuneus (CWP< 0.001), left middle frontal gyrus (CWP< 0.001) and lateral orbital frontal cortex (CWP=0.004). Higher L5 was linked with cortical thinning in the left superior temporal sulcus (CWP=0.004), superior middle temporal cortex (CWP=0.010) and middle temporal gyrus (CWP=0.013), as well as right inferior parietal lobe (CWP< 0.001). Lower IS was associated with cortical thinning in the left (CWP=0.002) and right (CWP< 0.001) superior frontal gyri, left superior temporal gyrus (CWP=0.043) and left post-central gyrus (CWP=0.033). Conclusions Markers of circadian rhythmicity are associated with reduced cortical thickness in frontal, temporal and occipital cortices in older adults ‘at risk’ for dementia. Future work is still required to delineate whether brain degeneration leads to altered daily rhythms and/or if circadian misalignment contributes to cognitive decline longitudinally.

Non-abstinent recovery in alcohol use disorder is associated with greater regional cortical volumes than heavy drinking.

Harm-reduction (i.e., non-abstinent recovery) approaches to substance use treatment have garnered increasing attention. Reduced levels of alcohol consumption post-treatment have been associated with better psychosocial functioning and physical health, yet less is known regarding differences in brain structures associated with varying levels of alcohol consumption. This study investigated regional cortical volumes after alcohol use disorder (AUD) treatment among individuals who achieved complete abstinence and those who returned to lower and higher levels of consumption. Data were collected from individuals with AUD (n = 68) approximately 8 months after the initiation of treatment. Using risk drinking levels defined by the World Health Organization, participants were classified as abstaining (AB) or relapsing with low (RL) or higher (RH) levels. Data were also obtained from 34 age-matched light/non-drinking controls (LN). All participants completed a 1.5 T magnetic resonance imaging session and volumes for 34 bilateral cortical regions of interest were quantitated with FreeSurfer. Generalized linear models were used to examine group differences in cortical volume. All group findings are significant at an FDR-corrected value of 0.018. Adjusting for age and intracranial volume, significant group differences were found in 13/34 cortical regions. AB showed greater volumes than RL in 2/13 regions and RH in 6/13 regions. RH demonstrated significantly smaller volumes than LN in 12/13 ROIs, whereas RL differed from LN in 9/13 regions. RH and RL differed in only two cortical regions. Individuals who consumed low-risk levels of alcohol post-treatment exhibited regional cortical volumes more similar to abstainers than individuals who returned to higher-risk levels. This suggests that low-risk levels of alcohol consumption are associated with brain integrity that is comparable to that seen with complete abstinence. Given the previously demonstrated improvement in psychosocial and physical health with reduced levels of alcohol consumption post-treatment, harm reduction may be a beneficial and more attainable goal for some individuals with AUD who are seeking treatment.

Neurodevelopment among children exposed to HIV and uninfected in sub-Saharan Africa.

The population of 16 million children exposed to HIV and uninfected (CHEU) under 15 years of age continues to expand rapidly, and the estimated prevalence of CHEU exceeds 20% in several countries in sub-Saharan Africa with high HIV prevalence. Some evidence suggests that CHEU experience suboptimal neurodevelopmental outcomes compared to children born to women without HIV. In this commentary, we discuss the latest research on biologic and socio-behavioural factors associated with neurodevelopmental outcomes among CHEU. Some but not all studies have noted that CHEU are at risk of poorer neurodevelopment across multiple cognitive domains, most notably in language and motor skills, in diverse settings, ages and using varied assessment tools. Foetal HIV exposure can adversely influence infant immune function, structural brain integrity and growth trajectories. Foetal exposure to antiretrovirals may also influence outcomes. Moreover, general, non-CHEU-specific risk factors for poor neurodevelopment, such as preterm birth, food insecurity, growth faltering and household violence, are amplified among CHEU; addressing these factors will require multi-factorial solutions. There is a need for rigorous harmonised approaches to identify children at the highest risk of delay. In high-burden HIV settings, existing maternal child health programmes serving the general population could adopt structured early child development programmes that educate healthcare workers on CHEU-specific risk factors and train them to conduct rapid neurodevelopmental screening tests. Community-based interventions targeting parent knowledge of optimal caregiving practices have shown to be successful in improving neurodevelopmental outcomes in children and should be adapted for CHEU. CHEU in sub-Saharan Africa have biologic and socio-behavioural factors that may influence their neurodevelopment, brain maturation, immune system and overall health and wellbeing. Multidisciplinary research is needed to disentangle complex interactions between contributing factors. Common environmental and social risk factors for suboptimal neurodevelopment in the general population are disproportionately magnified within the CHEU population, and it is, therefore, important to draw on existing knowledge when considering the socio-behavioural pathways through which HIV exposure could impact CHEU neurodevelopment. Approaches to identify children at greatest risk for poor outcomes and multisectoral interventions are needed to ensure optimal outcomes for CHEU in sub-Saharan Africa.

Perspectives on informed assent and bodily integrity in prospective deep brain stimulation for youth with refractory obsessive-compulsive disorder

Background Deep brain stimulation is approved for treating refractory obsessive-compulsive disorder in adults under the US Food and Drug Administration Humanitarian Device Exemption, and studies have shown its efficacy in reducing symptom severity and improving quality of life. While similar deep brain stimulation treatment is available for pediatric patients with dystonia, it is not yet available for pediatric patients with obsessive-compulsive disorder, although soon could be. The prospect of growing indications for pediatric deep brain stimulation raises several ethical concerns relating to bodily integrity, the ability to offer informed assent, and the role pediatric patients play in the decision-making process. Objective The aim of this study is to solicit and assess the views of stakeholders (children, parents, clinicians) on pediatric assent, autonomy, and bodily integrity in the context of potential pediatric deep brain stimulation for obsessive-compulsive disorder. Methods Semi-structured interviews were conducted with pediatric obsessive-compulsive disorder patients ( n = 21), caregivers of pediatric obsessive-compulsive disorder patients aged 14–18 ( n = 19), and clinicians with experience treating refractory obsessive-compulsive disorder ( n = 25). Interviews were transcribed and coded in MAXQDA 2018 and 2020 software and processed for thematic content analysis to isolate and compare specific themes. Results A majority of respondents (74%, 48/65) across all three stakeholder groups voiced that the decision-making process should be collaborative and involve everyone (clinicians: 84% or 21/25, caregivers 71% or 15/21, and patients 63% or 12/19). We identified a split between respondents’ views on who should have the final say in the event of disagreement (38% or 25/65 favored the patient versus 35% or 23/65 favoring caregivers). A split between respondents also emerged concerning the maturity relevant for deep brain stimulation decision-making, with 45% (29/65) favoring developmental maturity (age/physiological development) and 45% (29/65) favoring decisional maturity (capacity to understand and weigh information). A majority of clinicians indicated that they would not move forward with deep brain stimulation without securing patient assent (80% or 20/25), with some stating the only exception is if patient quality of life was very poor and/or they lacked insight. Both caregivers and patients expressed a significant respect for the patient's right to bodily integrity, with 67% of caregivers (14/21) and 68% of patients (13/19) justifying patient involvement in decision-making specifically with reference to infringements of bodily integrity. Conclusion Our findings demonstrate that despite broad agreement across stakeholders that the decision-making process for pediatric deep brain stimulation for obsessive-compulsive disorder should be collaborative and somehow involve pediatric patients, there is disagreement about what this process entails and what factors determine patient involvement in the process. However, there is agreement that children have a right to bodily and brain integrity, which should only be infringed upon in rare circumstances.

Contributions of Cardiovascular Burden, Peripheral Inflammation, and Brain Integrity on Digital Clock Drawing Performance in Non-Demented Older Adults.

Greater cardiovascular burden and peripheral inflammation are associated with dysexecutive neuropsychological profiles and a higher likelihood of conversion to vascular dementia. The digital clock drawing test (dCDT) is useful in identifying neuropsychological dysfunction related to vascular etiology. However, the specific cognitive implications of the combination of cardiovascular risk, peripheral inflammation, and brain integrity remain unknown. We aimed to examine the role of cardiovascular burden, inflammation, and MRI-defined brain integrity on dCDT latency and graphomotor metrics in older adults. 184 non-demented older adults (age 69±6, 16±3 education years, 46% female, 94% white) completed dCDT, vascular assessment, blood draw, and brain MRI. dCDT variables of interest: total completion time (TCT), pre-first hand latency, digit misplacement, hour hand distance from center, and clock face area. Cardiovascular burden was calculated using the Framingham Stroke Risk Profile (FSRP-10). Peripheral inflammation markers included interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-alpha, and high sensitivity C-reactive protein. Brain integrity included bilateral entorhinal cortex volume, lateral ventricular volume, and whole brain leukoaraiosis. FSRP-10, peripheral inflammation, and brain integrity explained an additional 14.6% of the variance in command TCT, where FSRP-10 was the main predictor. FSRP-10, inflammatory markers, and brain integrity explained an additional 17.0% in command digit misplacement variance, with findings largely driven by FSRP-10. Subtle graphomotor behavior operationalized using dCDT metrics (i.e., TCT and digit misplacement) is partly explained by cardiovascular burden, peripheral inflammation, and brain integrity and may indicate vulnerability to a disease process.