Biology subjects

Rajagopal, S.

Publications and source records attributed to Rajagopal, S..

At least 19 recordsLinked to original sources

bioRxiv2026

Multi-lineage emergence of USA300 MRSA in in Chile and a potential role for environmental copper resistance

Methicillin-resistant S. aureus (MRSA) is prevalent worldwide, but individual strains of MRSA tend to spread and expand in relatively confined geographic areas. The USA300 lineage of MRSA is most well-known for its rapid epidemic spread in North America during the first decade of the 2000's leading to an overall increase in serious skin infections and the emergence of methicillin resistance in the majority of community acquired S. aureus infections. A distinct but closely related South American epidemic clade of MRSA USA300 (USA300-SAE), first reported in 2006, proliferated rapidly in Northern South America but was rarely found in other Latin American countries. In a new survey of 274 invasive MRSA isolates from 2022 collected in Chile, we saw a marked increase in USA300-SAE in Southern South America. We found that Chilean USA300-SAE is phylogenetically diverse and was likely introduced multiple times from multiple different South American countries over the course of more than a decade, but only recently became a highly prevalent clone. Using novel molecular diagnostic methods for isolates collected in 2023, we estimate that USA300-SAE made up more than 22% of invasive MRSA strains in Chile in that year and is likely still increasing. We show that copper-associated genes in the signature copper and mercury resistance mobile element (COMER) of USA300-SAE are strongly conserved, and that isogenic mutants of the copper resistance genes in COMER are highly susceptible to copper killing at concentrations seen in tap water. These findings suggest that environmental exposure to copper may provide a fitness advantage that enhances spread of this lineage.

microbiology↗

bioRxiv2026

BCKDK Inhibitors Directly Antagonize Angiotensin II Type 1 Receptor and Induce Vasodilation Independently of BCAA Catabolism or BCKDK

Branched-chain amino acids (BCAA) have been implicated in diabetes and heart failure, leading to ongoing clinical trials with inhibitors of BCKDK, a key regulator of BCAA catabolism. We have previously shown that these inhibitors promote vasodilation and lower blood pressure, well-known cardioprotective effects, but how this occurs remained unclear. We show here, using explanted vessels, in vivo hemodynamics and telemetry, and genetically modified mice, that the vasodilatory effect of BCKDK inhibitors is direct, rapid, independent of nitric oxide, independent of BCAA catabolism, and most strikingly, independent of BCKDK itself. Instead, we demonstrate, using structural and biochemical studies, that BCKDK inhibitors directly antagonize the angiotensin II type I receptor (AT1R) and consequent angiotensin-mediated vasoconstriction. These data demonstrate a strong off-target effect of BCKDK inhibitors, independent of BCAA or BCKDK, which may explain their cardioprotective effects but also questions if this protection would be additive to existing AT1R blockers.

physiology↗

bioRxiv2026

Changes in peripheral sensory afference do not alter predictive motor planning: evidence from carpal tunnel syndrome

Anticipatory control organises motor output prior to predictable perturbations and is expressed in multi-digit tasks as anticipatory synergy adjustments (ASAs), which coordinate digit forces before movement onset. Whether such feedforward coordination depends on peripheral sensory input remains unclear. Carpal tunnel syndrome provides a model of altered median nerve afference with within-subject restoration following surgical decompression. We quantified ASA onset and amplitude in eleven individuals with carpal tunnel syndrome performing a multi-finger grasp-and-release task before and three weeks after decompression surgery. Postoperatively, sensory function improved, and total grip force decreased significantly across task phases, indicating more efficient force regulation. In contrast, ASA onset timing and amplitude were unchanged. Equivalence testing confirmed that pre- and post-operative ASA measures fell within predefined bounds of practical equivalence. These findings demonstrate a central-peripheral dissociation: feedback-mediated grip force scaling is sensory-dependent and rapidly recalibrates following afferent restoration, whereas feedforward synergy coordination remains stable despite months of degraded peripheral input. The preserved ASA suggests that central motor planning circuits maintain anticipatory coordination through efferent copy or cerebellar-mediated internal models that do not require continuous peripheral recalibration. This resilience may reflect the brains ability to maintain predictive motor planning despite chronic sensory degradation, with implications for understanding compensatory mechanisms in peripheral neuropathies and the limits of sensory-dependent motor adaptation.

neuroscience↗

bioRxiv2025

CXCR1 and CXCR2 display receptor bias for shared chemokine agonists

G protein-coupled receptors (GPCRs) mediate diverse signaling outputs through their proximal transducers: G proteins, GRKs, and {beta}-arrestins. Although ligand bias at chemokine receptors (CKRs), where ligands for the same receptor display distinct signaling patterns, is well recognized, receptor bias, where the same agonist at different receptors yields distinct transducer engagement, remains poorly understood. We compared endogenous chemokine ligands (CXCL1, CXCL5, CXCL7, CXCL8) at the highly homologous CXCR1 and CXCR2 receptors using biosensor assays to measure Gi activation, {beta}-arrestin1/2 recruitment, GRK2/3/5/6 translocation, and receptor internalization. Our data reveal qualitatively different signaling patterns, most notably where CXCL1 acts as a G protein-biased partial agonist at CXCR1 but as a balanced full agonist at CXCR2. These signaling differences correlate with receptor internalization but not subcellular ERK activation patterns measured using compartment-specific biosensors. Collectively, our findings demonstrate receptor bias in CKR signaling, transducer activation, and compartmentalized kinase activation in translating chemokine identity into discrete functional outcomes. SIGNIFICANCE STATEMENTChemokine ligand bias, where different ligands for the same receptor display different signaling patterns, is now well appreciated. However, there are only few examples of receptor bias, where the same agonist generates distinct signaling profiles at different receptors. Here we used biosensors and compartmental ERK biosensors, to show that CXCL1, CXCL5, CXCL7, and CXCL8 differentially engage G proteins, {beta}-arrestins, and GRKs, at CXCR1 and CXCR2. This work provides mechanistic insight into CXCR1/CXCR2 signaling diversity.

biochemistry↗

bioRxiv2025

β-arrestin recruitment facilitates a direct association with G proteins

G protein-coupled receptors (GPCRs) are targets for almost a third of all FDA-approved drugs. GPCRs are known to signal through both heterotrimeric G proteins and {beta}-arrestins. Traditionally these pathways were viewed as largely separable, with G proteins primarily initiating downstream signaling while {beta}-arrestins modulate receptor trafficking and desensitization in addition to regulating their own signaling events. Recent studies suggest an integrated role of G proteins and {beta}-arrestins in GPCR signaling, however the cellular and biochemical requirements for G protein: {beta}-arrestin interactions remain unclear. Here we show that G proteins and {beta}-arrestins can directly interact. Through utilization of {beta}-arrestin-biased receptors and artificially enforced {beta}-arrestin relocalization, we demonstrate that recruitment of {beta}-arrestin to the plasma membrane is sufficient to interact with the G protein Gi. Using purified proteins, we show that Gi directly interacts with {beta}-arrestin. In addition, we find that Gi family members differ in their degree of association with {beta}-arrestin, and that a large degree of this selectivity resides within the alpha helical domain of Gi. These findings delineate the cellular and biochemical conditions that drive direct interactions between G proteins and {beta}-arrestins and illuminate the molecular basis for how they work together to effect GPCR signaling.

biochemistry↗

bioRxiv2025

β-Arrestin Condensates Regulate G Protein-Coupled Receptor Function

G protein-coupled receptors (GPCRs) are the largest class of receptors in the genome and control many signaling cascades essential for survival. GPCR signaling is regulated by {beta}-arrestins, multifunctional adapter proteins that direct receptor desensitization, internalization, and signaling. While at many GPCRs, {beta}-arrestins interact with a wide array of signaling effectors, it is unclear how {beta}-arrestins promote such varied functions. Here we show that {beta}-arrestins undergo liquid-liquid phase separation (LLPS) to form condensates that regulate GPCR function. We demonstrate that {beta}-arrestin oligomerization occurs in proximity to the GPCR and regulates GPCR functions such as internalization and signaling. This model is supported by a cryoEM structure of the adhesion receptor ADGRE1 in a 2:2 complex with {beta}-arrestin 1, with a {beta}-arrestin orientation that can promote oligomerization. Our work provides a paradigm for {beta}-arrestin condensates as regulators of GPCR function, with LLPS serving as an important promoter of signaling compartmentalization at GPCRs.

cell biology↗

bioRxiv2024

Location-biased β-arrestin conformations direct GPCR signaling

{beta}-arrestins are multifunctional intracellular proteins that regulate the desensitization, internalization and signaling of over 800 different G protein-coupled receptors (GPCRs) and interact with a diverse array of cellular partners1,2. Beyond the plasma membrane, GPCRs can initiate unique signaling cascades from various subcellular locations, a phenomenon known as "location bias"3,4. Here, we investigate how {beta}-arrestins direct location-biased signaling of the angiotensin II type I receptor (AT1R). Using novel bioluminescence resonance energy transfer (BRET) conformational biosensors and extracellular signal-regulated kinase (ERK) activity reporters, we reveal that in response to the endogenous agonist Angiotensin II and the {beta}-arrestin-biased agonist TRV023, {beta}-arrestin 1 and {beta}-arrestin 2 adopt distinct conformations across different subcellular locations, which are intricately linked to differential ERK activation profiles. We also uncover a population of receptor-free catalytically activated {beta}-arrestins in the plasma membrane that exhibits insensitivity to different agonists and promotes ERK activation on the plasma membrane independent of G proteins. These findings deepen our understanding of GPCR signaling complexity and also highlight the nuanced roles of {beta}-arrestins beyond traditional G protein pathways.

biochemistry↗

bioRxiv2024

Menopause status and sex affect memory for spatial context information and white matter microstructure at midlife

Decline in spatial context memory emerges in midlife, the time when most females transition from pre-to post-menopause. Recent evidence suggests that, among post-menopausal females, advanced age is associated with functional brain alterations and lower spatial context memory. However, it is unknown whether similar effects are evident for white matter (WM) and, moreover, whether such effects contribute to sex differences at midlife. To address this, we conducted a study on 96 cognitively unimpaired middle-aged adults (30 males, 32 pre-menopausal females, 34 post-menopausal females). Spatial context memory was assessed using a face-location memory paradigm, while WM microstructure was assessed using diffusion tensor imaging. Behaviorally, advanced age was associated with lower spatial context memory in post-menopausal females but not pre-menopausal females or males. Additionally, advanced age was associated with microstructural variability in predominantly frontal WM (e.g., anterior corona radiata, genu of corpus callosum), which was related to lower spatial context memory among post-menopausal females. Our findings suggest that post-menopausal status enhances vulnerability to age effects on the brains WM and episodic memory.

neuroscience↗

bioRxiv2024

ACKR3 Proximity Labeling Identifies Novel G protein- and β-arrestin-independent GPCR Interacting Proteins

The canonical paradigm of GPCR signaling recognizes G proteins and {beta}-arrestins as the two primary transducers that promote GPCR signaling. Recent evidence suggests the atypical chemokine receptor 3 (ACKR3) does not couple to G proteins, and {beta}-arrestins are dispensable for some of its functions. Here, we employed proximity labeling to identify proteins that interact with ACKR3 in cells devoid of {beta}-arrestin. We identified proteins involved in the endocytic machinery and evaluated a subset of proteins conserved across several GPCR-based proximity labeling experiments. We discovered that the bone morphogenic protein 2-inducible kinase (BMP2K) interacts with many different GPCRs with varying dependency on {beta}-arrestin. Together, our work highlights the existence of modulators that can act independently of G proteins and {beta}-arrestins to regulate GPCR signaling and provides important evidence for other targets that may regulate GPCR signaling. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=190 SRC="FIGDIR/small/577545v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@56a61org.highwire.dtl.DTLVardef@18b17baorg.highwire.dtl.DTLVardef@c2bd55org.highwire.dtl.DTLVardef@11c39b0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2023

The influence of chronological age and menopause status on the functional neural correlates of spatial context memory in middle-aged females.

Reductions in the ability to encode and retrieve past experiences in rich spatial contextual detail (episodic memory) are apparent by midlife - a time when most females experience spontaneous menopause. Yet, little is known about how menopause status affects episodic memory-related brain activity at encoding and retrieval in middle-aged pre- and post-menopausal females, and whether any observed group differences in brain activity and memory performance correlate with chronological age within group. We conducted an event-related task fMRI study of episodic memory for spatial context to address this knowledge gap. Multivariate behavioral partial least squares (PLS) was used to investigate how chronological age and retrieval accuracy correlated with brain activity in 31 premenopausal (age range: 39.55 - 53.30 yrs, Mage = 44.28 yrs, SDage = 3.12 yrs) and 41 postmenopausal females (age range: 46.70 to 65.14 yrs, Mage = 57.56 yrs, SDage = 3.93 yrs). We found that postmenopausal status, and advanced age within post-menopause, was associated with lower spatial context memory. The fMRI analysis showed that only in postmenopausal females, advanced age was correlated with decreased activity in occipitotemporal, parahippocampal, and inferior parietal during encoding and retrieval, and poorer spatial context memory performance. In contrast, only premenopausal females exhibited an overlap in encoding and retrieval activity in angular gyrus, midline cortical regions, and prefrontal cortex, which correlated with better spatial context retrieval accuracy. These results highlight how menopause status and chronological age, nested within menopause group, affect episodic memory and its neural correlates at midlife. Significance StatementThis is the first fMRI study to examine how pre- and post-menopause status affects the neural correlates of episodic memory encoding and retrieval, and how chronological age contributes to any observed group similarities and differences. We found that both menopause status (endocrine age) and chronological age affect spatial context memory and its neural correlates. Menopause status directly affected the direction of age- and performance-related correlations with brain activity in inferior parietal, parahippocampal and occipitotemporal cortices across encoding and retrieval. Moreover, we found that only premenopausal females exhibited cortical reinstatement of encoding-related activity in midline cortical, prefrontal, and angular gyrus, at retrieval. This suggests that spatial context memory abilities may rely on distinct brain systems at pre-compared to post-menopause.

neuroscience↗

bioRxiv2023

Tag attachment reduces the initiation of recruitment in the rock ant, Temnothorax rugatulus

Technological advances continue to push the boundaries of scientific inquiry in animal behavior. One such development is the emergence of automated tracking systems, which enable the collection of high-resolution spatio-temporal information for animals. Although tag-based tracking systems provide valuable insights into animal movement and collective behavior, the attachment of devices can have detrimental effects in some cases. Here, we investigated the effects of recently developed miniature tracking tags using the rock ant, Temnothorax rugatulus, as a model system. To do so, we compared the foraging activities of tagged and untagged ants within partially tagged colonies. Additionally, we compared the foraging activities of these tagged colonies with those of untagged control colonies. We found that tags did not reduce individual activity, with tagged ants visiting the food source as frequently as untagged ants. However, our analysis revealed a marked difference in recruitment behavior--tagged ants were significantly less likely to participate in tandem runs. This study demonstrates, for the first time, that tracking tags can negatively impact ant behavior. Although tracking devices are powerful tools for understanding complex behavioral patterns, it is crucial to carefully consider their potential impact on animal behavior to ensure accurate conclusions.

ecology↗

bioRxiv2023

Phosphorylation barcodes direct biased chemokine signaling at CXCR3

G protein-coupled receptor (GPCR) biased agonism, the activation of some signaling pathways over others, is thought to largely be due to differential receptor phosphorylation, or "phosphorylation barcodes." At chemokine receptors, ligands act as "biased agonists" with complex signaling profiles, which contributes to the limited success in pharmacologically targeting these receptors. Here, mass spectrometry-based global phosphoproteomics revealed that CXCR3 chemokines generate different phosphorylation barcodes associated with differential transducer activation. Chemokine stimulation resulted in distinct changes throughout the kinome in global phosphoproteomic studies. Mutation of CXCR3 phosphosites altered {beta}-arrestin conformation in cellular assays and was confirmed by molecular dynamics simulations. T cells expressing phosphorylation-deficient CXCR3 mutants resulted in agonist- and receptor-specific chemotactic profiles. Our results demonstrate that CXCR3 chemokines are non-redundant and act as biased agonists through differential encoding of phosphorylation barcodes and lead to distinct physiological processes.

biochemistry↗

bioRxiv2022

Subcellular localization of GPCR kinases differentially modulate biased signaling at CXCR3

Some G protein-coupled receptors (GPCRs) demonstrate biased signaling, where ligands of the same receptor differentially activate specific downstream signaling pathways over others. Ligand-specific receptor phosphorylation by GPCR kinases (GRKs) is one mechanism underlying this phenomenon. Recent evidence demonstrates that GPCRs traffic to and signal from subcellular compartments beyond the plasma membrane, a paradigm termed location bias. Here, we show that GRKs translocate to endosomes following stimulation of the chemokine receptor CXCR3 and other GPCRs. The GRK recruitment patterns at the plasma membrane and endosome are distinct and depend on the identity of the ligand used to activate the receptor. Using cells deficient of GRKs, we demonstrate that biased ligands have unique signaling profiles upon rescue of location-specific GRK isoforms. Our work highlights a role of the GRKs in location-biased GPCR signaling and demonstrates the complex interactions between ligand, GRK isoform and cellular location that contribute to biased signaling.

biochemistry↗

bioRxiv2022

Endothelial beta-arrestins Regulate Mechanotransduction by the Type II Bone Morphogenetic Protein Receptor in Primary Cilia

RationaleModulation of endothelial cell behavior and phenotype by hemodynamic forces involves many signaling components, including cell surface receptors, intracellular signaling intermediaries, transcription factors, and epigenetic elements. Many of the signaling mechanisms that underlie mechanotransduction by endothelial cells are inadequately defined. ObjectiveWe sought to better understand how {beta}-arrestins, intracellular proteins that regulate agonist-mediated desensitization and integration of signaling by transmembrane receptors, may be involved in the endothelial cell response to shear stress. Methods and ResultsIn vitro studies with primary endothelial cells subjected to {beta}-arrestin knockdown, and in vivo studies using mice with endothelial specific deletion of {beta}-arrestin 1 and {beta}-arrestin 2 were conducted. We found that {beta}-arrestins are localized to primary cilia in endothelial cells, which are present in subpopulations of endothelial cells in relatively low shear states. Recruitment of {beta}-arrestins to cilia involved its interaction with IFT81, a component of the flagellar transport protein complex in the cilia. {beta}-arrestin knockdown led to marked reduction in shear stress response, including induction of NOS3 expression. Within the cilia, {beta}-arrestins were found to associate with the type II bone morphogenetic protein receptor (BMPR-II), whose disruption similarly led to an impaired endothelial shear response. {beta}-arrestins also regulated Smad transcription factor phosphorylation by BMPR-II. Mice with endothelial specific deletion of {beta}-arrestin 1 and {beta}-arrestin 2 were found to have impaired retinal angiogenesis. ConclusionWe have identified a novel role for endothelial {beta}-arrestins as key transducers of ciliary mechanotransduction that play a central role in shear signaling by BMPR-II and contribute to vascular development. NOVELTY AND SIGNIFICANCE What Is Known?O_LIEndothelial cells respond to flow-induced shear stress with biochemical changes, such as phosphorylation of endothelial nitric oxide synthase, that promote morphological changes, such as cell alignment. C_LIO_LIThe endothelial response to shear stress can involve primary cilia, microtubule-based sensory organelles that detect extracellular stimuli and generates intracellular signals. C_LIO_LIThe specific ciliary signaling pathways that regulate endothelial mechanotransduction have not been fully elucidated. C_LI What New Information Does This Article Contribute?O_LI{beta}-arrestins directly interact with the ciliary protein intraflagellar transport protein 81 (IFT81), which is present in the primary cilia of endothelial cells, and are required for the morphological response to flow-induced shear stress. C_LIO_LI{beta}-arrestins regulates type II bone morphogenetic protein receptor signaling, which is required for the endothelial response to shear stress, and is required for the phosphorylation of Smad transcription factors. C_LIO_LI{beta}-arrestins are required for endothelial nitric oxide synthase-mediated flow-induced shear stress response in endothelial cells. C_LIO_LIEndothelial cell-specific knockout of {beta}-arrestins results in abnormal vascular development, with a loss of vessel length and branchpoints. C_LI

molecular biology↗

bioRxiv2022

Single-Cell Analysis Identifies Distinct Immune and Smooth Muscle Cell Populations that Contribute to Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a sequelae of acute pulmonary embolism (PE) in which the PE remodels into a chronic scar in the pulmonary arteries. This results in vascular obstruction, small vessel arteriopathy and pulmonary hypertension. Our current understanding of CTEPH pathobiology is primarily derived from cell-based studies limited by the use of specific cell markers or phenotypic modulation in cell culture. Here we used single cell RNA sequencing (scRNAseq) of tissue removed at the time of pulmonary thromboendarterectomy (PTE) surgery to identify the multiple cell types, including macrophages, T cells, and smooth muscle cells, that comprise CTEPH thrombus. Notably, multiple macrophage subclusters were identified but broadly split into two categories, with the larger group characterized by an upregulation of inflammatory signaling predicted to promote pulmonary vascular remodeling. Both CD4+ and CD8+ T cells were identified and likely contribute to chronic inflammation in CTEPH. Smooth muscle cells were a heterogeneous population, with a cluster of myofibroblasts that express markers of fibrosis and are predicted to arise from other smooth muscle cell clusters based on pseudotime analysis. Additionally, cultured endothelial, smooth muscle and myofibroblast cells isolated from CTEPH thrombus have distinct phenotypes from control cells with regards to angiogenic potential and rates of proliferation and apoptosis. Lastly, our analysis identified protease-activated receptor 1 (PAR1) as a potential therapeutic target that links thrombosis to chronic PE in CTEPH, with PAR1 inhibition decreasing smooth muscle cell and myofibroblast proliferation and migration. These findings suggest a model for CTEPH similar to atherosclerosis, with chronic inflammation promoted by macrophages and T cells driving vascular remodeling through smooth muscle cell modulation, and suggest new approaches for pharmacologically targeting this disease.

pathology↗

bioRxiv2022

Location bias contributes to functionally selective responses of biased CXCR3 agonists

Some G protein-coupled receptor (GPCR) ligands act as "biased agonists" which preferentially activate specific signaling transducers over others. Although GPCRs are primarily found at the plasma membrane, GPCRs can traffic to and signal from many subcellular compartments. Here, we determine that differential subcellular signaling contributes to the biased signaling generated by three endogenous ligands of the chemokine GPCR CXCR3. The signaling profile of CXCR3 changed as it trafficked from the plasma membrane to endosomes in a ligand-specific manner. Endosomal signaling was critical for biased activation of G proteins, {beta}-arrestins, and ERK1/2. In CD8+ T cells, the chemokines promoted unique transcriptional responses predicted to regulate inflammatory pathways. In a mouse model of contact hypersensitivity, {beta}-arrestin-biased CXCR3-mediated inflammation was dependent on receptor internalization. Our work demonstrates that differential subcellular signaling is critical to the overall biased response observed at CXCR3, which has important implications for drugs targeting chemokine receptors and other GPCRs.

biochemistry↗

bioRxiv2021

Environment dependent benefits of individual differences in the recruitment behaviour of honey bees

Inter-individual differences in behaviour within the members of a social group can affect the groups productivity. In eusocial insects, individual differences amongst workers in a colony play a central role division of labour and task allocation. Extensive empirical and theoretical work has highlighted variation in response thresholds as a proximate mechanism underlying individual behavioural differences and hence division of labour. However, other response parameters, like response probability and intensity, can affect these differences. In this study, we first extended a previously published agent-based model on honey bee foraging to understand the relative importance of response (dance) probability and response (dance) intensity in the task of recruitment. Comparing variation obtained from the simulations with previously published empirical data, we found that response intensity plays a more important role than probability in producing consistent inter-individual differences in recruitment behaviour. We then explored the benefits provided by this individual variation in recruitment behaviour to the colonys collective foraging effort under different environmental conditions. Our results revealed that individual variation leads to a greater energetic yield per forager, but only when food is abundant. Our study highlights the need to consider all response parameters while studying division of labour and adds to the growing body of evidence linking individual variation in behavioural responses to the success of social groups.

animal behavior and cognition↗

bioRxiv2021

Sex differences in age- and episodic memory-related effects on task-based functional connectivity

Aging is associated with episodic memory decline and changes in functional brain connectivity. Understanding whether and how biological sex influences age- and memory performance-related functional connectivity has important theoretical and clinical implications for our understanding of brain and cognitive aging. Yet, little is known about the effect of sex on neurocognitive aging. Here, we scanned 161 healthy adults between 19-76 yrs of age in an event-related functional magnetic resonance imaging (fMRI) study of face-location spatial context memory. Adults were scanned while performing easy and difficult versions of the task at both encoding and retrieval. We used multivariate whole-brain partial least squares (PLS) connectivity to test the hypothesis that there are sex differences in age- and episodic memory performance-related functional connectivity. We examined how individual differences in age and retrieval accuracy correlated with task-related connectivity. We then repeated this analysis after disaggregating the data by self-reported sex. We found that increased encoding and retrieval-related connectivity within the dorsal attention network (DAN), and between DAN and frontoparietal network (FPN) and visual networks, was positively correlated to retrieval accuracy and negatively correlated with age in both sexes. We also observed sex differences in age- and performance-related functional connectivity: i) greater between-network integration was apparent at both levels of task difficulty in women only, and ii) increased DAN-DMN connectivity with age was observed in men and was correlated with poorer memory performance. Therefore, the neural correlates of age-related episodic memory decline differ in women and men and has important theoretical and clinical implications for the cognitive neuroscience of memory, aging and dementia prevention.

neuroscience↗