Biology subjects

Weiner, K. S.

Publications and source records attributed to Weiner, K. S..

34 records · Page 2Linked to original sources

bioRxiv2022

Ventral temporal and posteromedial sulcal morphology in autism spectrum disorder

Two recent parallel research tracks link tertiary sulcal morphology--sulci that emerge last in gestation and continue to develop after birth--with functional features of the cerebral cortex and cognition, respectively. The first track identified a relationship between the mid-fusiform sulcus (MFS) in ventral temporal cortex (VTC) and cognition in individuals with Autism Spectrum Disorder (ASD). The second track identified a new tertiary sulcus, the inframarginal sulcus (IFRMS), that serves as a tripartite landmark within the posteromedial cortex (PMC). As VTC and PMC are structurally and functionally different in individuals with ASD compared to neurotypical controls (NTs), here, we integrated these two tracks with a twofold approach. First, we tested if there are morphological differences in VTC and PMC sulci between 50 NTs and 50 individuals with ASD. Second, we tested if tertiary sulcal morphology was linked to cognition in ASD individuals. Our twofold approach replicates and extends recent findings in five ways. First, in terms of replication, the standard deviation (STD) of MFS cortical thickness (CT) was increased in ASDs compared to NTs. Second, MFS length was shorter in ASDs compared to NTs. Third, the CT STD effect extended to other VTC and PMC sulci. Fourth, a subset of VTC and PMC morphological features were correlated between regions in ASD. Fifth, IFRMS depth was negatively associated with ADOS-GS score. These results empirically support a relationship between later-developing, tertiary sulci and ASD, providing a novel framework to study the relationship between brain structure and cognition in additional neurodevelopmental disorders in future studies. Lay SummaryWe observed that some, but not all, morphological features of later-developing tertiary indentations (sulci) in the cerebral cortex differed significantly between neurotypical controls and individuals with autism spectrum disorder (ASD). In ASD, a subset of sulcal morphological features also correlated between brain areas and one feature reflected differences in cognition. Thus, studying these structures provides insight into how individual variability in structure is related to individual variability in cognition in ASD.

neuroscience↗

bioRxiv2022

Superficial white matter across the lifespan: volume, thickness, change, and relationship with cortical features

Superficial white matter (SWM) represents a significantly understudied part of the human brain, despite comprising a large portion of brain volume and making up a majority of cortical structural connections. Using multiple, high-quality, datasets with large sample sizes (N=2421, age range 5-100) in combination with methodological advances in tractography, we quantified features of SWM volume and thickness across the brain and across the lifespan. We address four questions: (1) How does U-fiber volume change with age? (2) What does U-fiber thickness look like across the brain? (3) How does SWM thickness change with age? (4) Are there relationships between SWM thickness and cortical features? Our main findings are that (1) SWM volume shows unique volumetric trajectories with age that are distinct from gray matter and other white matter trajectories; (2) SWM thickness varies across the brain, with patterns robust across individuals and across the population at the region-level and vertex-level; (3) SWM shows nonlinear changes across the lifespan that vary across regions; and (4) SWM thickness is associated with cortical thickness and curvature. For the first time, we show that SWM volume follows a similar trend as overall white matter volume, peaking at a similar time in adolescence, leveling off throughout adulthood, and decreasing with age thereafter. Notably, the relative fraction of total brain volume of SWM continuously increases with age, and consequently takes up a larger proportion of total white matter volume, unlike the other tissue types that decrease with respect to total brain volume. This study represents the first characterization of SWM features across the lifespan and provides the background for characterizing normal aging and insight into the mechanisms associated with SWM development and decline.

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bioRxiv2022

Distinct population and single-neuron selectivity for executive and episodic processing in human dorsal posterior cingulate

Posterior cingulate cortex (PCC) is an enigmatic region implicated in psychiatric and neurological disease, yet its role in cognition remains unclear. Human studies link PCC to episodic memory and default mode network (DMN), while findings from the non-human primate emphasize executive processes more associated with the cognitive control network (CCN) in humans. We hypothesized this difference reflects an important functional division between dorsal (executive) and ventral (episodic) PCC. To test this, we utilized human intracranial recordings of population and single unit activity targeting dorsal PCC during an alternated executive/episodic processing task. Dorsal PCC population responses were significantly enhanced for executive, compared to episodic, task conditions, consistent with the CCN. Single unit recordings, however, revealed four distinct functional types with unique executive (CCN) or episodic (DMN) response profiles. Our findings provide critical electrophysiological data from human PCC, bridging incongruent views within and across species, furthering our understanding of PCC function.

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bioRxiv2022

Defining tertiary sulci in lateral prefrontal cortex in chimpanzees using human predictions

Similarities and differences in brain structure and function across species is of major interest in systems neuroscience, comparative biology, and brain mapping. Recently, increased emphasis has been placed on tertiary sulci, which are shallow indentations of the cerebral cortex that appear last in gestation, continue to develop after birth, and are largely either human- or hominoid-specific. While tertiary sulcal morphology in lateral prefrontal cortex (LPFC) has been linked to functional representations and cognition in humans, it is presently unknown if LPFC tertiary sulci also exist in non-human hominoids. To fill this gap in knowledge, we leveraged two freely available multimodal datasets to address the following main question: Can LPFC tertiary sulci be defined in chimpanzee cortical surfaces from human predictions? We found that 1-3 components of the posterior middle frontal sulcus (pmfs) in the posterior middle frontal gyrus are identifiable in nearly all chimpanzee hemispheres. In stark contrast to the consistency of the pmfs components, we could only identify components of the paraintermediate frontal sulcus (pimfs) in two chimpanzee hemispheres. LPFC tertiary sulci were relatively smaller and shallower in chimpanzees compared to humans. In both species, two of the pmfs components were deeper in the right compared to the left hemisphere. As these results have direct implications for future studies interested in the functional and cognitive role of LPFC tertiary sulci across species, we share probabilistic predictions of the three pmfs components to guide the definitions of these sulci in future studies.

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bioRxiv2022

Functionally and structurally distinct fusiform face area(s) in over 1000 participants

The Fusiform Face Area (FFA) is a widely studied region causally involved in face perception. Even though cognitive neuroscientists have been studying the FFA for over two decades, answers to foundational questions regarding the structure, function, and connectivity of the FFA from a large (N>1000) group of participants are still lacking. To fill this gap, we quantified structural, functional, and connectivity features of fusiform face-selective regions in 1080 participants in the Human Connectome Project (HCP). After manually defining over 4,000 fusiform face-selective regions, we report five main findings. First, 68.94% of hemispheres have two cortically separate regions (pFus-faces/FFA-1 and mFus-faces/FFA-2). Second, in 26.48% of hemispheres, pFus-faces/FFA-1 and mFus-faces/FFA-2 are spatially contiguous, yet functionally and structurally distinct. Third, pFus-faces/FFA-1 is more face-selective than mFus-faces/FFA-2, and the two regions have distinct functional connectivity fingerprints. Fourth, pFus-faces/FFA-1 is cortically thinner and more heavily myelinated than mFus-faces/FFA-2. Fifth, face-selective patterns and functional connectivity fingerprints of each region were more similar in monozygotic than dizygotic twins and more so than structural gradients. As we share our areal definitions with the field, future studies can explore how structural and functional features of these regions will inform theories regarding how visual categories are represented in the brain.

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bioRxiv2022

Presence or absence of a prefrontal sulcus is linked to reasoning performance during child development

The relationship between structural variability in late-developing association cortices like the lateral prefrontal cortex (LPFC) and the development of higher-order cognitive skills is not well understood. Recent findings show that the morphology of LPFC sulci predicts reasoning performance; this work led to the observation of substantial individual variability in the morphology of one of these sulci, the para-intermediate frontal sulcus (pimfs). Here, we sought to characterize this variability and assess its behavioral significance. To this end, we identified the pimfs in a developmental cohort of 72 participants, ages 6-18. When controlling for age, the presence or absence of the ventral component of the pimfs was associated with reasoning, as was the total surface area of pimfs. These findings show that multiple features of sulci can support the development of complex cognitive abilities and highlight the importance of considering individual differences in local morphology when exploring the neurodevelopmental basis of cognition.

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bioRxiv2022

Hominoid-specific sulcal variability is related to face perception ability

Human perception requires complex cortical networks that function at neuroanatomical scales of microns and temporal scales of milliseconds. Despite this complexity, what if just one morphological feature of the brain could predict perceptual ability? Here, we tested this hypothesis with pre-registered analyses of neuroanatomy and face perception in neurotypical controls (NTs) and individuals with developmental prosopagnosia (DPs). Results show that the length of the mid-fusiform sulcus (MFS), a hominoid-specific tertiary sulcus in ventral temporal cortex (VTC), was shorter in DPs than NTs. Furthermore, individual differences in MFS length in the right, but not left, hemisphere predicted individual differences in face perception. These results support theories linking brain structure and function to perception, as well as indicate that one feature - variability in MFS length - can predict face perception. Finally, these findings add to growing evidence supporting a role of morphological variability of late developing, tertiary sulci and individual differences in cognition.

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bioRxiv2021

Sulcal depth in prefrontal cortex: A novel predictor of working memory performance

The neuroanatomical changes that underpin cognitive development is of major interest in neuroscience. Of the many aspects of neuroanatomy to consider, tertiary sulci are particularly appealing as they emerge last in gestation, show a protracted development after birth, and are either human- or hominoid-specific. Thus, they are ideal targets for exploring morphological-cognitive relationships with cognitive skills, such as verbal working memory (WM), that also show protracted development. Yet, the relationship between sulcal morphology and verbal WM is unknown, either in development or more generally. To fill this gap, we adopted a data-driven approach with cross-validation to examine the relationship between sulcal depth in lateral prefrontal cortex (LPFC) and verbal WM in 60 participants ages 6-18. These analyses identified nine left, but not right, LPFC sulci (of which six were tertiary) whose depth predicted verbal WM performance. Most of these sulci are located within and around contours of functionally defined parcellations of LPFC proposed previously. This sulcal depth model out-performed models with age or cortical thickness. Taken together, these findings contribute to building empirical support for a classic theory that tertiary sulci serve as landmarks in association cortices that contribute to aspects of human behavior that show a protracted development.

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bioRxiv2021

A new tripartite landmark in posterior cingulate cortex

Understanding brain structure-function relationships, and their development and evolution, is central to neuroscience research. Here, we show that morphological differences in posterior cingulate cortex (PCC), a hub of functional brain networks, predict individual differences in macroanatomical, microstructural, and functional features of PCC. Manually labeling 4,319 sulci in 552 hemispheres, we discovered a consistently localized shallow cortical indentation (termed the inframarginal sulcus; ifrms) within PCC that is absent from neuroanatomical atlases, yet co-localized with a region within the cognitive control, but not default mode, network. Morphological analyses in humans and chimpanzees showed that unique properties of the ifrms differ across the lifespan and between hominoid species. Intriguingly, the consistency of the ifrms also debunks the uniqueness of the morphology of Einsteins PCC. These findings support a classic theory that shallow, tertiary sulci serve as landmarks in association cortices. They also beg the question: how many other cortical indentations have we missed?

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bioRxiv2020

Cognitive insights from evolutionarily new brain structures in prefrontal cortex

While the disproportionate expansion of lateral prefrontal cortex (LPFC) in humans compared to non-human primates is accepted, the relationship between evolutionarily new LPFC brain structures and uniquely human cognitive skills is largely unknown. Here, we tested the relationship between variability in evolutionarily new LPFC tertiary sulci and reasoning skills in a pediatric cohort. A novel data-driven approach in independent discovery and replication samples revealed that the depth of specific LPFC tertiary sulci predicts individual differences in reasoning skills beyond age. These findings support a classic, yet untested, theory linking the protracted development of tertiary sulci to late-developing cognitive processes. We suggest that deeper LPFC tertiary sulci reflect reduced short-range connections in white matter, which in turn, improve the efficiency of local neural signals underlying cognitive skills such as reasoning that are central to human cognitive development. To expedite discoveries in future neuroanatomical-behavioural studies, we share sulcal definitions with the field.

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bioRxiv2020

Extensive individual differences of category information in ventral temporal cortex in the congenitally blind

Human ventral temporal cortex (VTC) is a cortical expanse that performs different functions and computations, but is especially critical for visual categorization. Nevertheless, accumulating evidence shows that category-selective regions persist in VTC in the absence of visual experience - for example, in congenitally blind (CB) participants. Despite this evidence, a large body of previous work comparing functional representations in VTC between sighted and CB participants performed univariate analyses at the group level, which assume a homogeneous population - an assumption that has not been formally tested until the present study. Specifically, using fMRI in CB and sighted participants (male and female), we empirically show that at the group level, distributed category representations in VTC are more reliable in the sighted (when viewing visual stimuli) compared to the CB (when hearing auditorily-substituted visual stimuli). Despite these group differences, there is extensive heterogeneity in VTC category representations in the CB to the point that VTC category representations in a subset of CB participants (some who were born without eyes, but not all) are more similar to sighted individuals compared to other CB participants. Together, our findings support a novel idea that driving factors contributing to the formation of VTC category representations in the blind are subject-specific, which complements factors that may generalize across group members. More broadly, the present findings caution conclusions of homogeneity across subjects within a group when performing group neuroimaging analyses without explicitly quantifying individual differences.

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bioRxiv2020

A new sulcal landmark identifying anatomical and functional gradients in human lateral prefrontal cortex

Understanding the relationship between neuroanatomy and function in portions of human cortex that are expanded compared to other mammals such as lateral prefrontal cortex (LPFC) is of major interest in systems and cognitive neuroscience. When considering neuroanatomical-functional relationships in LPFC, shallow indentations in cortex known as tertiary sulci have been largely ignored. Here, by implementing a multi-modal approach and manually defining 936 neuroanatomical structures in 72 hemispheres (males and females), we show that a subset of these overlooked tertiary sulci serve as a meso-scale link between microstructural (myelin content) and functional (network connectivity) properties of human LPFC in individuals. For example, the posterior middle frontal sulcus (pmfs) is a tertiary sulcus with three components that differ in their myelin content, resting state connectivity profiles, and engagement across meta-analyses of 83 cognitive tasks. Further, generating microstructural profiles of myelin content across cortical depths for each pmfs component and the surrounding middle frontal gyrus (MFG) shows that both gyral and sulcal components of the MFG have greater myelin content in deeper compared to superficial layers and that the myelin content in superficial layers of the gyral components is greater than sulcal components. These findings support a classic, yet largely unconsidered theory that tertiary sulci may serve as landmarks in association cortices, as well as a modern cognitive neuroscience theory proposing a functional hierarchy in LPFC. As there is a growing need for computational tools that automatically define tertiary sulci throughout cortex, we share pmfs probabilistic sulcal maps with the field. Significance statementLateral prefrontal cortex (LPFC) is critical for higher-order cognitive control and goal-directed behavior and is disproportionately expanded in the human brain. However, relationships between fine-scale neuroanatomical structures largely specific to hominoid cortex and functional properties of LPFC remain elusive. Here, we show that these structures, which have been largely neglected throughout history, surprisingly serve as markers for anatomical and functional organization in human LPFC. These findings have theoretical, methodological, developmental, and evolutionary implications for improved understanding of neuroanatomical-functional relationships not only in LPFC, but also in association cortices more broadly. Finally, these findings ignite new questions regarding how morphological features of these neglected neuroanatomical structures contribute to functions of association cortices that are critical for human-specific aspects of cognition.

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bioRxiv2020

Sulcal depth in medial ventral temporal cortex predicts the location of a place-selective region in macaques, children, and adults.

The evolution and development of anatomical-functional relationships in the cerebral cortex is of major interest in neuroscience. Here, we leveraged the fact that a functional region selective for visual scenes is located within a sulcus in medial ventral temporal cortex (VTC) in both humans and macaques to examine the relationship between sulcal depth and place-selectivity in medial VTC across species and age groups. To do so, we acquired anatomical and functional magnetic resonance imaging scans in 9 macaques, 26 human children, and 28 human adults. Our results revealed a strong structural-functional coupling between sulcal depth and place-selectivity across age groups and species in which selectivity was strongest at the deepest sulcal point (the sulcal pit). Interestingly, this coupling between sulcal depth and place-selectivity strengthens from childhood to adulthood in humans. Morphological analyses suggest that the stabilization of sulcal-functional coupling in adulthood may be due to sulcal deepening and areal expansion with age as well as developmental differences in cortical curvature at the pial, but not the white matter surfaces. Our results implicate sulcal features as functional landmarks in high-level visual cortex and highlight that sulcal-functional relationships in medial VTC are preserved between macaques and humans despite differences in cortical folding.

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bioRxiv2019

Opposing transcriptomic gradients explain orthogonal maps in human visual areas

Opposing transcriptomic gradients explain the large-scale organization of cortex. Here, we show that opposing transcriptomic gradients also explain the fine-scale organization of orthogonal maps in human visual areas. We propose a model relating transcriptomics, cell density, and function, which predicts that specific cortical locations within these visual maps are microanatomically distinct and differentially susceptible to genetic mutations. We conclude with histological and translational data that support both predictions.

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bioRxiv2018

Modeling neural tuning in human ventral temporal cortex predicts the perception of visual ambiguity

We have an amazing ability to categorize objects in the world around us. Nevertheless, how cortical regions in human ventral temporal cortex (VTC), which is critical for categorization, support this behavioral ability, is largely unknown. Here, we examined the relationship between neural responses and behavioral performance during the categorization of morphed silhouettes of faces and hands, which are animate categories processed in cortically adjacent regions in VTC. Our results reveal that the combination of neural responses from VTC face- and body-selective regions more accurately explains behavioral categorization than neural responses from either region alone. Furthermore, we built a model that predicts a persons behavioral performance using estimated parameters of brain-behavioral relationships from a different group of people. We further show that this brain-behavioral model generalizes to adjacent face- and body-selective regions in lateral occipito-temporal cortex. Thus, while face- and body-selective regions are located within functionally-distinct domain-specific networks, cortically adjacent regions from both networks likely integrate neural responses to resolve competing and perceptually ambiguous information from both categories.

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bioRxiv2018

Apparent thinning of visual cortex during childhood is associated with myelination, not pruning

Microstructural mechanisms underlying apparent cortical thinning during childhood development are unknown. Using functional, quantitative, and diffusion magnetic resonance imaging in children and adults, we tested if tissue growth (lower T1 relaxation time and mean diffusivity (MD)) or pruning (higher T1 and MD) underlies cortical thinning in ventral temporal cortex (VTC). After age 5, T1 and MD decreased in mid and deep cortex of functionally-defined regions in lateral VTC, and in their adjacent white matter. T1 and MD decreases were (i) consistent with tissue growth related to myelin proliferation, which we verified with adult postmortem histology and (ii) correlated with apparent cortical thinning. Thus, contrary to prevailing theories, cortical tissue does not thin during childhood, it becomes more myelinated, shifting the gray-white matter boundary deeper into cortex. As tissue growth is prominent in regions with protracted functional development, our data suggest an intriguing hypothesis that functional development and myelination are interlinked.

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