Biology subjects

Ali, T.

Publications and source records attributed to Ali, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Dozens of genetic variants sustain adaptation to urban spatial heterogeneity in Arabidopsis thaliana

Urbanization creates mosaics of microhabitats that sustain diverse plant communities and offer untapped opportunities to understand contemporary ecological and evolutionary processes. Using a city-wide colonization experiment in Cologne (Germany), we identified the environmental factors limiting establishment and persistence of the ruderal species Arabidopsis thaliana and the genetic variants enabling adaptation. We show that standing genetic variation is essential for realizing the species urban niche, enabling rapid adaptation to fine-scale gradients in disturbance, vegetation, and soil conditions. Despite originating from only two parental genotypes, populations evolved substantial adaptive differentiation within three generations, revealing a highly polygenic basis of local adaptation. More broadly, our approach establishes cities as powerful open-air laboratories for uncovering and fostering ecological and evolutionary processes that generate and sustain biodiversity in human-dominated landscapes.

evolutionary biology↗

bioRxiv2026

Species-specific drivers of genetic diversity are decoupled from plant community diversity

Understanding how habitat connectivity shapes biodiversity remains a major ecological challenge. In particular, the roles of connectivity and ecological heterogeneity on co-variation in plant species diversity and intraspecific genetic diversity is not understood. We combined species distribution modelling, resistance-to-movement mapping, landscape connectivity analysis and population genomics to investigate diversity patterns in three wet meadow herbs, Scorzonera humilis, Oenanthe peucedanifolia and Lychnis flos-cuculi, and their surrounding plant communities. Genetic diversity patterns differed strongly among co-occurring species. Connectivity metrics explained genetic diversity only in O. peucedanifolia, and environmental drivers of genetic diversity were highly species specific. Importantly, genetic diversity changed with the presence of some species in the community, but it was consistently unrelated to indicators of local plant community diversity. Overall, the processes shaping within-species biodiversity may differ fundamentally from those structuring habitat connectivity and plant species communities, with important implications for conservation.

ecology↗

bioRxiv2026

Heterologous expression of lyngbyatoxin biosynthetic genes in Aspergillus oryzae reveals transcriptional barriers but enables LtxC-mediated biotransformation

Cyanobacterial natural products are a rich source of bioactive compounds, yet their heterologous production remains challenging. This study investigates the feasibility of expressing the lyngbyatoxin A (LTXA) biosynthetic gene cluster in a fungal host. The lyngbyatoxin biosynthetic genes (ltxA, ltxB, ltxC) were individually cloned and expressed in Aspergillus oryzae NSAR1 under the control of an inducible promoter. Metabolite production was assessed using LC- MS, and transcriptional analysis was performed by RT-PCR. Codon-optimized constructs and precursor feeding experiments were employed to evaluate pathway functionality. No production of LTXA or pathway intermediates was detected upon co-expression of ltxA-C despite confirmed transcription of ltxB and ltxC. RT-PCR analysis revealed truncation of the ltxA transcript, suggesting incompatibility with fungal transcriptional or splicing machinery. In contrast, expression of a codon-optimized ltxC enabled biotransformation of indolactam V to LTXA in A. oryzae, confirming functional expression of the prenyltransferase. These results highlight transcriptional limitations as a key barrier to heterologous expression of cyanobacterial NRPS pathways in fungal hosts, while demonstrating that downstream tailoring enzymes can remain functional. This work provides insights for future engineering of fungal platforms for cyanobacterial natural product biosynthesis.

synthetic biology↗

bioRxiv2026

ER Stress-Induced beta-Cell Apoptosis is Linked to Novel Select Lipid Signaling at the Transcriptional Level: Implications in T1D Development

Type 1 diabetes (T1D) is a consequence of {beta}-cell death. ER stress precedes T1D onset and prolonged ER stress in {beta}-cells can lead to {beta}-cell apoptosis. We reported that lipid signaling generated by the Ca2+-independent phospholipase A2{beta} (iPLA2{beta}), encoded by Pla2g6, participates in ER stress-mediated {beta}-cell apoptosis. {beta}-Cell membranes are enriched in arachidonic acid containing glycerophospholipids and the iPLA2{beta} catalyzes the hydrolysis of arachidonic acid in ER stressed {beta}-cells. Metabolism of arachidonic acid leads to the generation of various proinflammatory lipids, raising the possibility that they contribute to ER stress and {beta}-cell death leading to T1D. However, molecular mechanisms by which such {beta}-cell-iPLA2{beta}-derived lipid (iDL) signaling contributes to {beta}-cell apoptosis are not understood. It is well known that ER stress-mediated {beta}-cell apoptosis is associated with induction of transcription factors, NF{kappa}B and STAT1. We report here that both induce Pla2g6 and, unexpectedly, we find that iPLA2{beta}, which lacks DNA-binding motifs, associates with NFkB, Stat1, and Pla2g6 promoter regions. Consistently, p65-NF{kappa}B and pSTAT1 induction is reduced with select inhibition or knockdown of iPLA2{beta}. Surprisingly, iPLA2{beta} expression is also reduced by select inhibition of iPLA2{beta}, raising the possibility of feedback regulation by iDLs. In support, we find that select iDLs, recognized to be proinflammatory, enhance association of iPLA2{beta} with Pla2g6, Nfkb, and Stat1 promoter regions leading to induction of all three gene products and {beta}-cell apoptosis. Our findings reveal previously unrecognized transcriptional regulation by iDL signaling and, iPLA2{beta} itself, that leads to gene products that promote {beta}-cell apoptosis. Analogous findings in human islets validate this mechanism raising the possibility that targeting select lipid signaling can reduce ER stress in {beta}-cells and ameliorate T1D development.

cell biology↗

bioRxiv2026

Investigating the versatility of cytochalasan cytochrome P450 monooxygenases using combinatorial biosynthesis reveals stereochemical restrictions

BackgroundCytochalasans are a large family of fungal metabolites which inhibit actin polymerization and ultimately lead to a broad range of biological effects in different assays. Investigations into the biosynthesis of cytochalasans has revealed that the cytochrome P450 monooxygenase (P450s) tailoring enzymes possess a somewhat relaxed substrate-specificity and may accept structurally-related intermediates for oxidation, partly explaining the variety of structural variations observed in this family of molecules. In this study, we investigate a broad range of P450 enzymes via combinatorial biosynthesis to better understand their substrate scope and potential applications as biocatalysts. ResultsGenome mining enabled us to identify cryptic cytochalasan biosynthetic gene clusters (BGCs) in six different species of fungi, each with at least two P450 enzymes encoded. Comparative genomics identified a cryptic thioredoxin-like enzyme encoded in cytochalasan BGCs that co-occurs with the gene encoding a Baeyer-Villiger monooxygenase. Heterologous expression of seven P450s in Magnaporthe grisea mutant strains, lacking P450s required for pyrichalasin H biosynthesis, enabled functional characterization of three P450s, two of which were previously cryptic. The experimental results, combined with phylogenetic analysis of the P450 sequences, reveal subtle information regarding the structures of the associated cytochalasans and begins to explain why some P450s are inactive on the substrates available to them. ConclusionsThe P450 enzymes involved in cytochalasan biosynthesis are known to be site-selective in their native host but also possess intrinsic promiscuity due to being able to modify structurally-related analogues. By investigating a diverse set of P450s from characterized and cryptic BGCs, we were able to identify that the stereochemistry of functional groups around the cytochalasan backbone is more restrictive than the size of the macrocycle when introducing the P450 enzyme to non-native substrates.

biochemistry↗

bioRxiv2025

The complex molecular basis of enhanced stress resilience in extreme drought-tolerant Arabis grassland species

Background and AimsPlant species in competitive meadows must tolerate extreme stress, yet the mechanisms underlying resilience remain poorly understood. Arabis nemorensis, an endangered selfing species of Euro- pean floodplain grasslands, experiences both flooding and drought and hybridizes with its close relative, A. sagittata. We investigated how these species differ in drought survival and the molec- ular basis of their responses. MethodsSympatric lineages of A. nemorensis and A. sagittata were compared in a controlled dry-down experiment, complemented by transcriptome and small RNA profiling, and machine-learning anal- ysis of cis-regulatory motifs. Key ResultsBoth species wilted at 5% soil moisture, but A. sagittata recovered more effectively (90% vs. 50%). This difference was not explained by a major QTL, suggesting a polygenic basis. Transcrip- tome profiling revealed stronger induction in A. sagittata (6,359 vs. 5,571 differentially expressed genes). Small RNA analysis identified species-specific regulation of miR408, a conserved drought regulator. Machine-learning identified 307 sequence motifs predictive of stress-responsive expres- sion, with motif distributions indicating distinct regulatory networks. ConclusionsThis study reveals the polygenic and regulatory complexity underlying divergent drought resili- ence strategies in the closely related species thriving in grassland environments. Arabis nemorensis and its close relative A. sagittata co-occur in a floodplain meadow exposed to flooding and drought. In dry-down experiments, A. sagittata recovered more effectively than A. nemorensis. Transcriptome and small RNA analyses revealed stronger stress responses in A. sagittata, including regulation of miR408. These differences result from different regulatory networks and have a polygenic basis.

plant biology↗

bioRxiv2025

Contemporary hybridization among Arabis floodplain species creates opportunities for adaptation

Hybridization between closely related species is increasingly recognized as a major source of biodiversity. Yet, whether it can create advantageous trait combinations while purging harmful alleles remains unknown. We studied Arabis nemorensis and A. sagittata, two endangered species that currently hybridize in a single hotspot. We measured 22 phenotypic traits and mapped their genetic basis in an F2 population, after generating high quality genome assemblies for both species. In total, 58 QTLs were identified for 20 traits, with additive and dominance effects best fitting Gaussian and logistic distributions, respectively. Six large-effect QTLs were linked to significant hybrid fitness loss. Two genomic regions showed strong transmission bias favoring A. sagittata alleles, potentially accelerating their introgression. However, 48% of QTLs were unlinked to reduced fitness or segregation distortion and may generate genotypes exceeding parental performance. Notably, a major QTL affecting flowering time explained 23% of phenotypic variation and implicated TFL1 as a candidate gene for life history adaptation. While most QTLs lacked overlap with past selective sweeps, indicating limited recent positive selection, 5 of 7 QTLs for rosette size overlapped with sweep signatures in the parental lineages. Overall, our findings offer unique insights into incipient stages of hybridization.

evolutionary biology↗

bioRxiv2025

Heat-induced secondary dormancy contributes to local adaptation in Arabidopsis thaliana

Seeds should not germinate in conditions unsuitable for seedling growth. Dormancy, which allows seeds to remain inactive in an environment that would otherwise enable germination, helps optimize the timing of germination. Primary dormancy, developed during seed maturation on the parent plant, prevents immediate germination post-dispersal, regardless of external conditions. Secondary dormancy, however, is triggered post-dispersal when seeds face unfavorable conditions, enabling them to re-enter dormancy even if initially non-dormant. This mechanism allows seeds to fine-tune germination according to environmental conditions. In this study, we examined the role of heat-induced secondary dormancy in local adaptation by analyzing natural variations within 361 Arabidopsis thaliana accessions from across Europe. We discovered that secondary dormancy acquisition varies with primary dormancy levels and after-ripening. Both primary and heat-induced secondary dormancy exhibited adaptive clines along temperature and precipitation gradients, with secondary dormancy showing a steeper cline, indicating its significant role in local adaptation. Using species distribution models, we predicted that genotypes with high secondary dormancy would show greater resilience to future climate changes. Additionally, we identified specific genomic regions controlling secondary dormancy levels, including a novel candidate gene for secondary dormancy variation. Our findings show that secondary dormancy is a complex adaptive mechanism and a predominant contributor to the dormancy trait syndrome that favors plant survival in habitats exposed to harsh summers. Summary statementSecondary dormancy induced by heat exposure allows seed to adjust their germination strategies to the environment. This study shows that heat-induced secondary dormancy in Arabidopsis thaliana depends on levels of primary dormancy. Its covariance with climatic parameter indicates that it can contribute to population resilience to climate change. This study further identifies the specific genetics underlying the ability to induce dormancy after dispersal.

evolutionary biology↗

bioRxiv2024

A consensus variant-to-function score to functionally prioritize variants for disease

Identifying and functionally characterizing causal disease variants in genome-wide association studies remains a pressing challenge. Here, we construct a consensus variant-to-function (cV2F) score that assigns a single value to each common single-nucleotide variant in the genome, and helps to predict and characterize causal disease variants. The cV2F score leverages features reflecting variant-level experimentally and computationally predicted function (e.g. allelic imbalance and sequence-based deep learning models) and element-level function (e.g. predicted enhancers), and learns optimal combinations of features by training a gradient boosting model on GWAS fine-mapping results. The cV2F-annotated variants attained an AUPRC of 0.822 at identifying held-out fine-mapped variants. Variants with high cV2F scores are highly enriched for heritability (14.2x, s.e. 0.5) across 66 diseases/traits, are uniquely informative for disease heritability, and are highly predictive of variants implicated by reporter assays; cV2F substantially outperforms previous variant-to-function scores using all of these metrics. GWAS fine-mapping of 110 diseases/traits informed by cV2F identified 14.3% more confidently fine-mapped (PIP > 0.95) variants than non-functionally informed fine-mapping. We further constructed tissue/cell line-specific cV2F scores that prioritize variants based on regulatory potential in specific tissues/cell lines, attaining high heritability enrichment for tissue-related diseases/traits (15.6x, s.e. 2.3) while providing independent information (average correlation of 0.27 with the primary cV2F score). We highlight examples of GWAS loci for which cV2F pinpoints causal variants with high confidence and elucidates their functional role.

genetics↗

bioRxiv2024

The Area Law of Molecular Entropy: Moving Beyond Harmonic Approximation.

Inspired by black hole thermodynamics, the area law that entropy is proportional to horizon area has been proposed in quantum entanglement entropy and has largely maintained its validity. This article shows that the area law is also valid for the thermodynamic entropy of molecules. We showed that the gas-phase entropy of molecules obeys the area law with our proposed correction for the different curvatures of the molecular surface. The coefficient for the ultraviolet cutoff for the molecular entropy, calculated from our curated experimental data, is tantalizingly close to the value [Formula] proposed by Hawking [Hawking, 1976]. The ability to estimate gas-phase entropy by the area law also allows us to calculate molecular entropy faster and more accurately than currently popular methods of estimating molecular entropy with harmonic oscillator approximation. The speed and accuracy of our method will open up new possibilities for the explicit inclusion of entropy in computational biology methods, such as virtual screening applications.

biophysics↗

bioRxiv2022

Shift of the insoluble content of the proteome in aging mouse brain

Aging and protein aggregation diseases are inextricably linked. During aging, cellular response to unfolded proteins are believed to decline which results in diminished protein homeostasis (proteostasis). Indeed, in model organisms, such as C. elegans, proteostatic decline with age has even been linked to the onset of aggregation of proteins in wild-type animals. However, this correlation has not been extensively characterized in aging mammals. To reveal the insoluble portion of the proteome, we analyzed the detergent-insoluble fraction of mouse brain tissues after high-speed centrifugation by quantitative mass spectrometry. We identified a cohort of 171 proteins enriched in the pellet fraction of older mice including the alpha crystallin small heat shock protein. We then performed a meta-analysis to compare features among distinct groups of detergent-insoluble proteins reported in the literature. Surprisingly, our analysis revealed that features associated with proteins found in the pellet fraction differ depending on the ages of the mice. In general, insoluble proteins from young models (<15 weeks) were more likely to be RNA-binding, more disordered and more likely to be found in membraneless organelles. These traits become less prominent with age within the combined dataset, as proteins with more structure enter the pellet fraction. This analysis suggests that age-related changes to proteome organization lead a specific group of proteins to enter the pellet fraction as a result of loss of proteostasis.

cell biology↗

bioRxiv2022

Small-spored Alternaria spp. (section Alternaria) are common on wild tomato species

The wild relatives of modern tomato crops are native to South America. These plants occur in habitats as different as the Andes and the Atacama Desert and are to some degree all susceptible to fungal pathogens of the genus Alternaria. Alternaria is a large genus. On tomato, several species cause early blight, leaf spot, and other diseases. We collected Alternaria-like infection lesions from the leaves of eight wild tomato species from Chile and Peru. Using molecular barcoding markers, we characterized the pathogens. The infection lesions were caused predominantly by small-spored species of Alternaria of the section Alternaria, like A. alternata, but also by Stemphylium spp., Alternaria spp. from the section Ulocladioides, and other related species. Morphological observations and an infection assay confirmed this. Comparative genetic diversity analyses show a larger diversity in this wild system than in studies of cultivated Solanum species. As A. alternata has been reported to be an increasing problem on cultivated tomato, investigating the evolutionary potential of this pathogen is not only interesting to scientists studying wild plant-pathosystems. It could also inform crop protection and breeding programs to be aware of potential epidemics caused by species still confined to South America.

microbiology↗

bioRxiv2022

The lncRNA Sweetheart regulates compensatory cardiac hypertrophy after myocardial injury

After myocardial infarction in the adult heart the remaining, non-infarcted tissue adapts to compensate the loss of functional tissue. This adaptation requires changes in gene expression networks, which are mostly controlled by transcription regulating proteins. Long non-coding transcripts (lncRNAs) are now recognized for taking part in fine-tuning such gene programs. We identified and characterized the cardiomyocyte specific lncRNA Sweetheart RNA (Swhtr), an approximately 10 kb long transcript divergently expressed from the cardiac core transcription factor coding gene Nkx2-5. We show that Swhtr is dispensable for normal heart development and function, but becomes essential for the tissue adaptation process after myocardial infarction. Re-expressing Swhtr from an exogenous locus rescues the Swhtr null phenotype. Genes depending on Swhtr after cardiac stress are significantly occupied, and therefore most likely regulated by NKX2-5. Our results indicate a synergistic role for Swhtr and the developmentally essential transcription factor NKX2-5 in tissue adaptation after myocardial injury.

developmental biology↗

bioRxiv2022

X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and harvest index

O_LIAnnual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning and end of the lifetime of the vineyard. C_LIO_LIX-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits. C_LIO_LIModeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay thereafter, consistently shortening ring width throughout the lifetime of the vine. The ratio of yield to vegetative growth, juice pH, photosynthetic assimilation and transpiration rates, and stomatal conductance are correlated with scion trunk radius. C_LIO_LIRootstocks modulate secondary growth over years, altering hydraulic conductance, physiology, and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species. C_LI

plant biology↗

bioRxiv2022

Aging-regulated TUG1 is dispensable for endothelial cell function

The evolutionary conserved Taurine Upregulated Gene 1 (TUG1) is a ubiquitously expressed gene that is one of the highest expressed genes in human and rodent endothelial cells (ECs). We here show that TUG1 expression decreases significantly in aging mouse carotid artery ECs and human ECs in vitro, indicating a potential role in the aging endothelial vasculature system. We therefore investigated if, and how, TUG1 might function in aging ECs, but despite extensive phenotyping found no alterations in basal EC proliferation, apoptosis, barrier function, migration, mitochondrial function, or monocyte adhesion upon TUG1 silencing in vitro. TUG1 knockdown did slightly and significantly decrease cumulative sprout length upon vascular endothelial growth factor A stimulation in human umbilical vein endothelial cells (HUVECs), though TUG1-silenced HUVECs displayed no transcriptome-wide mRNA expression changes explaining this effect. Further, ectopic expression of the highly conserved and recently discovered 153 amino acid protein translated from certain TUG1 transcript isoforms did not alter angiogenic sprouting in vitro. Our data show that, despite a high expression and strong evolutionary conservation of both the TUG1 locus and the protein sequence it encodes, TUG1 does not seem to play a major role in basic endothelial cell function.

cell biology↗

bioRxiv2021

Fendrr synergizes with Wnt signalling to regulate fibrosis related genes during lung development

Long non-coding RNAs are a very versatile class of molecules that can have important roles in regulating a cells function, including regulating other genes on the transcriptional level. One of these mechanisms is that RNA can directly interact with DNA thereby recruiting additional components such as proteins to these sites via a RNA:dsDNA triplex formation. We genetically deleted the triplex forming sequence (FendrrBox) from the lncRNA Fendrr in mice and find that this FendrrBox is partially required for Fendrr function in vivo. We find that the loss of the triplex forming site in developing lungs causes a dysregulation of gene programs, associated with lung fibrosis. A set of these genes contain a triplex site directly at their promoter and are expressed in fibroblasts. We confirm the formation of RNA:dsDNA formation with target promoters. We find that Fendrr with the Wnt signalling pathway regulates these genes, implicating that Fendrr synergizes with Wnt signalling in lung fibrosis.

developmental biology↗

bioRxiv2021

P2X4 Purinergic Receptors as a Therapeutic Target in Aggressive Prostate Cancer

Prostate cancer (PCa) remains a leading cause of cancer-related deaths in American men and treatment options for metastatic PCa are limited. There is a critical need to identify new mechanisms that contribute to PCa progression, that distinguish benign from lethal disease, and that have potential for therapeutic targeting. P2X4 belongs to the P2 purinergic receptor family that is commonly upregulated in cancer and is associated with poorer outcomes. Herein, we report that the P2X4 purinergic receptor is overexpressed in PCa, associated with PCa metastasis, and a driver of tumor development in vivo. We observed P2X4 protein expression primarily in epithelial cells of the prostate, a subset of CD66+ neutrophils, and most CD68+ macrophages. Our analysis of tissue microarrays representing 491 PCa cases demonstrated significantly elevated P2X4 expression in cancer compared to benign tissue spots, in prostatic intraepithelial neoplasia, in cancer from White compared to Black men, and in PCa with ERG positivity or with PTEN loss. High P2X4 expression in benign tissues was likewise associated with the development of metastasis after radical prostatectomy. Treatment with P2X4-specific agonist CTP increased transwell migration and invasion of PC3, DU145, and CWR22Rv1 PCa cells. P2X4 antagonist 5-BDBD treatment resulted in a dose-dependent decrease in viability of PC3, DU145, LNCaP, CWR22Rv1, TRAMP-C2, Myc-CaP, BMPC1, and BMPC2 cells and decreased DU145 cell migration and invasion. Knockdown of P2X4 attenuated growth, migration, and invasion of PCa cells. Finally, knockdown of P2X4 in Myc-CaP cells resulted in significantly attenuated subcutaneous allograft growth in FVB/NJ mice. Collectively, these data strongly support a role for the P2X4 purinergic receptor in PCa aggressiveness and identifies P2X4 as a candidate for therapeutic targeting.

cancer biology↗

bioRxiv2021

Modelling the depth-dependent VASO and BOLD responses in human primary visual cortex

Functional magnetic resonance imaging (fMRI) using a blood-oxygenation-level-dependent (BOLD) contrast is a common method for studying human brain function non-invasively. Gradient-echo (GRE) BOLD is highly sensitive to the blood oxygenation change in blood vessels; however, the spatial signal specificity can be degraded due to signal leakage from activated lower layers to superficial layers in depth-dependent (also called laminar or layer-specific) fMRI. Alternatively, physiological variables such as cerebral blood volume using the VAscular-Space-Occupancy (VASO) contrast have shown higher spatial specificity compared to BOLD. To better understand the physiological mechanisms such as blood volume and oxygenation changes and to interpret the measured depth-dependent responses, models are needed which reflect vascular properties at this scale. For this purpose, we extended and modified the "cortical vascular model" previously developed to predict layer-specific BOLD signal changes in human primary visual cortex to also predict a layer-specific VASO response. To evaluate the model, we compared the predictions with experimental results of simultaneous VASO and BOLD measurements in a group of healthy participants. Fitting the model to our experimental data provided an estimate of CBV change in different vascular compartments upon neural activity. We found that stimulus-evoked CBV change mainly occurs in small arterioles, capillaries and intracortical arteries, and that the contribution from venules and ICVs is small. Our results confirm that VASO is less susceptible to large vessel effects compared to BOLD, as blood volume changes in intracortical arteries did not substantially affect the resulting depth-dependent VASO profiles, whereas depth-dependent BOLD profiles showed a bias towards signal contributions from intracortical veins.

neuroscience↗