Biology subjects

Maboudian, S. A.

Publications and source records attributed to Maboudian, S. A..

5 recordsLinked to original sources

bioRxiv2025

Overlooked neuroanatomical markers of face processing and developmental prosopagnosia in posteromedial cortex

Recent functional imaging studies implicate human posteromedial cortex (PMC)--composed of the posterior cingulate cortex, the precuneus, and retrosplenial cortex--in face processing. Separately, anatomical studies have identified previously overlooked cortical folds (sulci) in PMC associated with higher-level cognitive abilities. Here, we tested whether these newly identified sulci support face processing in neurotypical individuals and individuals with developmental prosopagnosia (DP). After manually labeling 1,642 sulci in 164 hemispheres, we first identified a gradient of face selectivity along the anterior-posterior axis of PMC that was consistent across three samples, including DP individuals. Second, we discovered a new anatomical locus in PMC that differed structurally and functionally between neurotypical and DP individuals. Finally, data-driven analysis revealed that right-hemisphere PMC sulcal morphology was associated with face recognition ability. These findings reveal a sulcal network in PMC that supports face processing, and they identify the first structural neuroanatomical marker of face processing deficits in PMC.

neuroscience↗

bioRxiv2025

Anterior cingulate folding pattern is altered in autism spectrum disorder

Neuroimaging research has identified focal differences in the cerebral cortex of individuals with autism spectrum disorder (ASD), particularly in the cortical folds (sulci) within higher-level association cortices. The present study investigated the sulcal patterning and morphology of the anterior cingulate cortex (ACC) in individuals with ASD compared to neurotypical (NT) individuals for the first time. We used neuroimaging data from 50 NT and 50 ASD participants. All participants were under 20 years old and male. The two groups were age-matched. Using established criteria and cortical reconstructions generated from each participants T1-weighted magnetic resonance imaging scans with FreeSurfer, we identified the defining sulcal feature of ACC, the variably present paracingulate sulcus (PCGS): its presence in the left and right hemispheres, and asymmetry in PCGS presence between hemispheres. Finally, multiple quantitative morphological features (length, depth, and cortical thickness mean and standard deviation) were extracted from the PCGS using FreeSurfer tools. Analyses revealed that NT participants were more likely to have asymmetrical PCGS patterns than ASD participants (controlling for age and scanner site). However, none of the quantitative morphological features differed between groups. These findings suggest the presence of a variation in the prenatal neurodevelopment of ACC in young males with ASD; however, further research is necessary to uncover the role of this observed difference in the pathogenesis of ASD. The present study also adds to the growing literature implicating variations in PCGS patterning as a trait marker across multiple disorders. Lay SummaryThis study found that young males with autism spectrum disorder (ASD) show less hemispheric asymmetry in the presence of a notoriously variable brain structure (paracingulate sulcus (PCGS)) compared to neurotypical individuals. Considering that this feature of the PCGS develops before birth, the reduced asymmetry may indicate focal differences in brain development in ASD. These findings further enhance our understanding of the neurodevelopmental characteristics of ASD and highlight growing findings indicating that the PCGS may be a useful transdiagnostic marker for various psychiatric conditions.

neuroscience↗

bioRxiv2024

Variable Presence of an Evolutionarily New Brain Structure is Related to Trait Impulsivity

BackgroundImpulsivity is a multidimensional construct reflecting poor constraint over ones behaviors. Clinical psychology research identifies separable impulsivity dimensions that are each unique transdiagnostic indicators for psychopathology. Yet, despite this apparent clinical importance, the shared and unique neuroanatomical correlates of these factors remain largely unknown. Concomitantly, neuroimaging research identifies variably present human brain structures implicated in cognition and disorder: the folds (sulci) of the cerebral cortex located in the latest developing and most evolutionarily expanded hominoid-specific association cortices. MethodsWe tethered these two fields to test whether variability in one such structure in anterior cingulate cortex (ACC)--the paracingulate sulcus (PCGS)--was related to individual differences in trait impulsivity. 120 adult participants with internalizing or externalizing psychopathology completed a magnetic resonance imaging scan and the Three-Factor Impulsivity Index. Using precision imaging techniques, we manually identified the PCGS, when present, and acquired quantitative folding metrics (PCGS length and ACC local gyrification index). ResultsNeuroanatomical-behavioral analyses revealed that participants with leftward or symmetrical PCGS patterns had greater severity of Lack of Follow Through (LFT)--which captures inattention and lack of perseverance--than those with rightward asymmetry. Neuroanatomical-functional analyses identified that the PCGS co-localized with a focal locus found in a neuroimaging meta-analysis on a feature underlying LFT. Both quantitative folding metrics did not relate to any impulsivity dimension. ConclusionsThis study advances understanding of the neuroanatomical correlates of impulsivity and establishes the notion that the topographical organization of distinct, hominoid-specific cortical expanses underlie separable impulsivity dimensions with robust, transdiagnostic implications for psychopathology.

neuroscience↗

bioRxiv2023

Defining overlooked structures reveals new associations between cortex and cognition in aging and Alzheimer's disease

Recent work suggests that indentations of the cerebral cortex, or sulci, may be uniquely vulnerable to atrophy in aging and Alzheimers disease (AD) and that posteromedial cortex (PMC) is particularly vulnerable to atrophy and pathology accumulation. However, these studies did not consider small, shallow, and variable tertiary sulci that are located in association cortices and are often associated with human-specific aspects of cognition. Here, we first manually defined 4,362 PMC sulci in 432 hemispheres in 216 participants. Tertiary sulci showed more age- and AD-related thinning than non-tertiary sulci, with the strongest effects for two newly uncovered tertiary sulci. A model-based approach relating sulcal morphology to cognition identified that a subset of these sulci were most associated with memory and executive function scores in older adults. These findings support the retrogenesis hypothesis linking brain development and aging, and provide new neuroanatomical targets for future studies of aging and AD.

neuroscience↗

bioRxiv2023

Sulcal morphology of posteromedial cortex substantially differs between humans and chimpanzees

Recent studies identify a surprising coupling between evolutionarily new sulci and the functional organization of human posteromedial cortex (PMC). Yet, no study has compared this modern PMC sulcal patterning between humans and non-human hominoids. To fill this gap in knowledge, we first manually defined 918 sulci in 120 chimpanzee (Pan Troglodytes) hemispheres and 1619 sulci in 144 human hemispheres. We uncovered four new PMC sulci, and quantitatively identified species differences in incidence, depth, and surface area. Interestingly, some PMC sulci are more common in humans and others, in chimpanzees. Further, we found that the prominent marginal ramus of the cingulate sulcus differs significantly between species. Contrary to classic observations, the present results reveal that the surface anatomy of PMC substantially differs between humans and chimpanzees -- findings which lay a foundation for better understanding the evolution of neuroanatomical-functional and neuroanatomical-behavioral relationships in this highly expanded region of the human cerebral cortex.

neuroscience↗