G. Auzias

• PhD
• Researcher at French National Centre for Scientific Research

Quality control (QC) has long been considered essential to guarantee the reliability of neuroimaging studies. It is particularly important for fetal brain MRI, where acquisitions and image processing techniques are less standardized than in adult imaging. In this work, we focus on automated quality control of super-resolution reconstruction (SRR) v...

The shape of human brain is complex and highly variable, with interactions between brain size, cortical folding, and age well-documented in the literature. However, few studies have explored how global brain size influences geometric features of the cortical surface derived from anatomical MRI. In this work, we focus on sulcal depth, an imaging phe...

Background: Super-resolution reconstruction (SRR) of fetal brain magnetic resonance imaging has the potential to enable the development of new imaging biomarkers to better study in utero neurodevelopment. However, potential biases in 2D biometric and 3D volumetric measurements due to different SRR techniques remain understudied. Purpose: To assess...

Quality assessment (QA) has long been considered essential to guarantee the reliability of neuroimaging studies. It is particularly important for fetal brain MRI, where unpredictable fetal motion can lead to substantial artifacts in the acquired images. Multiple images are then combined into a single volume through super-resolution reconstruction (...

The perinatal period involves transitioning from an intra- to an extrauterine environment, which requires a complex adaptation of the brain. This period is marked with dynamic and multifaceted cortical changes in both structure and function. Most studies to date have focused either on the fetal or postnatal period, independently. To the best of our...

Auditory verbal hallucinations (AVHs) are among the most common and disabling symptoms of schizophrenia. They involve the superior temporal sulcus (STS), which is associated with language processing; specific STS patterns may reflect vulnerability to auditory hallucinations in schizophrenia. STS sulcal pits are the deepest points of the folds in th...

The segregation of the cortical mantle into cytoarchitectonic areas provides a structural basis for the specialization of different brain regions. In vivo neuroimaging experiments can be linked to this postmortem cytoarchitectonic parcellation via Julich-Brain. This atlas embeds probabilistic maps that account for inter-individual variability in th...

Population-wise matching of the cortical folds is necessary to compute statistics, a required step for e.g. identifying biomarkers of neurological or psychiatric disorders. The difficulty arises from the massive inter-individual variations in the morphology and spatial organization of the folds. The task is challenging both methodologically and con...

Group level analyses of functional regions involved in voice perception show evidence of 3 sets of bilateral voice-sensitive activations in the human prefrontal cortex, named the anterior, middle and posterior Frontal Voice Areas (FVAs). However, the relationship with the underlying sulcal anatomy, highly variable in this region, is still unknown....

Neurodevelopmental disorders (NDDs) constitute a major health issue with >10% of the general worldwide population affected by at least one of these conditions—such as autism spectrum disorders (ASD) and attention deficit hyperactivity disorders (ADHD). Each NDD is particularly complex to dissect for several reasons, including a high prevalence of c...

Introduction Fetal alcohol spectrum disorders (FASD) range from fetal alcohol syndrome (FAS) to non-syndromic non-specific forms (NS-FASD) that are still underdiagnosed and could benefit from new neuroanatomical markers. The main neuroanatomical manifestation of prenatal alcohol exposure on developmental toxicity is the reduction in brain size, but...

Population-wise matching of the cortical fold is necessary to identify biomarkers of neurological or psychiatric disorders. The difficulty comes from the massive interindividual variations in the morphology and spatial organization of the folds. This task is challenging at both methodological and conceptual levels. In the widely used registration-b...

Background: Analyzing cortical folding may provide insight into the biological underpinnings of neurodevelopmental diseases. A neurodevelopmental subtype of bipolar disorders (BD-ND) has been characterized by the combination of early age of onset and psychotic features. We investigate potential cortical morphology differences associated with this...

Vectors fields defined on surfaces constitute relevant and useful representations but are rarely used. One reason might be that comparing vector fields across two surfaces of the same genus is not trivial: it requires to transport the vector fields from the original surfaces onto a common domain. In this paper, we propose a framework grounded on di...

Vectors fields defined on surfaces constitute relevant and useful representations but are rarely used. One reason might be that comparing vector fields across two surfaces of the same genus is not trivial: it requires to transport the vector fields from the original surfaces onto a common domain. In this paper, we propose a framework grounded on di...

Multigraph matching is a recent variant of the graph matching problem. In this framework, the optimization procedure considers several graphs and enforces the consistency of the matches along the graphs. This constraint can be formalized as a cycle consistency across the pairwise permutation matrices, which implies the definition of a universe of v...

IMPORTANCE: Papez circuit is composed of deep structures of the limbic system which supports episodic memory. Biomechanical modelling suggests that this circuit is particularly exposed to shear forces during traumatic brain injury (TBI). Recent studies showed the relevance of MRIderived measures for improving diagnosis and adapt care of TBI patient...

Small average differences in the left-right asymmetry of cerebral cortical thickness have been reported in individuals with autism spectrum disorder (ASD) compared to typically developing controls, affecting widespread cortical regions. The possible impacts of these regional alterations in terms of structural network effects have not previously bee...

Cytoarchitecture is a basic principle of brain microstructure used to define parcellations. To account for variations of the cytoarchitectonic parcellation between individual brains, a three-dimensional probabilistic atlas called the Jülich-Brain has been built from 23 postmortem brains [Amunts2020]. For this purpose, all the brains were aligned us...

Background Morphology of the human cerebral cortex differs across psychiatric disorders, with neurobiology and developmental origins mostly undetermined. Deviations in the tangential growth of the cerebral cortex during pre/peri-natal period may be reflected in individual variations in cortical surface area. Methods Inter-regional profiles of grou...

The human brain develops from a smooth cortical surface in early stages of fetal life to a convoluted one postnatally, creating an organized ensemble of folds. Abnormal folding patterns are linked to neurodevelopmental disorders. However, the complex multi-scale interactions involved in cortical folding are not fully known yet. Computational models...

Background: Traumatic brain injury (TBI) lesions are known to evolve over time, but the duration and consequences of cerebral remodeling are unclear. Degenerative mechanisms occurring in the chronic phase after TBI could constitute "tertiary" lesions related to the neurological outcome. Objective: The objective of this prospective study of sever...

Small average differences in the left-right asymmetry of cerebral cortical thickness have been reported in individuals with autism spectrum disorder (ASD) compared to typically developing controls. Although these alterations affect multiple and widespread cortical regional asymmetries, the extent to which specific structural networks might be affec...

Cortical folds help drive the parcellation of the human cortex into functionally specific regions. Variations in the length, depth, width, and surface area of these sulcal landmarks have been associated with disease, and may be genetically mediated. Before estimating the heritability of sulcal variation, the extent to which these metrics can be rel...

Importance Large-scale neuroimaging studies have revealed group differences in cortical thickness across many psychiatric disorders. The underlying neurobiology behind these differences is not well understood. Objective To determine neurobiologic correlates of group differences in cortical thickness between cases and controls in 6 disorders: atten...

Sulcal pits are the points of maximal depth within the folds of the cortical surface. These shape descriptors give a unique opportunity to access to a rich, fine-scale rep- resentation of the geometry and the developmental milestones of the cortical surface. However, using sulcal pits analysis at group level requires new numerical tools to establis...

Objective: Attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders that frequently co-occur. The authors sought to directly compare these disorders using structural brain imaging data from ENIGMA consortium data. Methods: Structural T1-weight...

Neuroimaging has been extensively used to study brain structure and function in individuals with attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) over the past decades. Two of the main shortcomings of the neuroimaging literature of these disorders are the small sample sizes employed and the heterogeneity of methods...

Background Hallucinations are the most common and debilitating symptom in schizophrenia, affecting more than 70% of patients. The superior temporal sulcus (STS) is involved in the language process notably in the perception of the human voice and several studies show its implication in auditory verbal hallucinations (AVHs). Sulcal patterns in the wh...

Altered structural brain asymmetry in autism spectrum disorder (ASD) has been reported. However, findings have been inconsistent, likely due to limited sample sizes. Here we investigated 1,774 individuals with ASD and 1,809 controls, from 54 independent data sets of the ENIGMA consortium. ASD was significantly associated with alterations of cortica...

The structure of the brain's cortical folds varies considerably in human populations. Specific patterns of cortical variation arise with development and aging, and cortical traits are partially influenced by genetic factors. The degree to which genetic factors affect cortical folding patterning remains unknown, yet may be estimated with large-scale...

jats:sec>Objective Attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders that frequently co-occur. We aimed to directly compare all three disorders. The ENIGMA consortium is ideally positioned to investigate structural brain alterations across...

We present a new framework for the creation of an extended atlas of short fiber bundles between 20 and 80 mm length. This method uses a Diffeomorphic inter-subject alignment procedure including information of cortical foldings and forces the accurate match of the sulci that have to be circumvented by the U-bundles. Then, a clustering is performed t...

Background: Left-right asymmetry is an important organizing feature of the healthy brain. Various studies have reported altered structural brain asymmetry in autism spectrum disorder (ASD). However, findings have been inconsistent, likely due to limited sample sizes and low statistical power. Methods: We investigated 1,774 subjects with ASD and 1,8...

Robust spatial alignment of post mortem data and in vivo MRI acquisitions from different ages, especially from the early developmental stages, into standard spaces is still a bottleneck hampering easy comparison with the mainstream neuroimaging results. In this paper, we test a landmark-based spatial normalization strategy as a framework for the se...

Understanding the link between structure, function and development in the brain is a key topic in neuroimaging that benefits from the tremendous progress of multi-modal MRI and its computational analysis. It implies, inter alia, to be able to parcellate the brain volume or cortical surface into biologically relevant regions. These parcellations may...

The asymmetry of the superior temporal sulcus (STS) has been identified as a species-specific feature of the human brain. The so-called superior temporal asymmetrical pit (STAP) area is observed from the last trimester of gestation onwards and is far less pronounced in the chimpanzee brain. This asymmetry is associated with more frequent sulcal int...

Objective: Neuroimaging studies show structural differences in both cortical and subcortical brain regions in children and adults with autism spectrum disorder (ASD) compared with healthy subjects. Findings are inconsistent, however, and it is unclear how differences develop across the lifespan. The authors investigated brain morphometry difference...

Objective: Neuroimaging studies show structural differences in both cortical and subcortical brain regions in children and adults with autism spectrum disorder (ASD) compared with healthy subjects. Findings are inconsistent, however, and it is unclear how differences develop across the lifespan. The authors investigated brain morphometry differenc...

Despite the large variability of sulcal folds, their deepest points, namely the sulcal pits, provide a sparse and reproducible description of the cortical surface. Their role during the antenatal and pediatric development of the brain remains unclear. This work is the first study of the evolution of all sulcal pits during healthy pediatric developm...

Understanding the link between structure, function and development in the brain is a key topic in neuroimaging that benefits from the tremendous progress of multi-modal MRI and its computational analysis. It implies, inter alia , to be able to parcellate the brain volume or cortical surface into biologically relevant regions. These parcellations ma...

The influence of genes on cortical structures has been assessed through various phenotypes. The sulcal pits, which are the putative first cortical folds, have for long been assumed to be under tight genetic control, but this was never quantified. We estimated the pit depth heritability in various brain regions using the high quality and large sampl...

Cognitive functions arise from the coordination of large-scale brain networks. However, the principles governing interareal functional connectivity dynamics (FCD) remain elusive. Here, we tested the hypothesis that human executive functions arise from the dynamic interplay of multiple networks. To do so, we investigated FCD mediating a key executin...

Significance statement: Executive functions are supported by the dynamic coordination of neural activity over large-scale networks. The properties of large-scale brain coordination processes, however, remain unclear. Using tools combining magnetoencephalography and intracranial electroencephalography with brain connectivity analyses, we provide ev...

Studying the topography of the cortex has proved valuable in order to characterize populations of subjects. In particular, the recent interest towards the deepest parts of the cortical sulci – the so-called sulcal pits – has opened new avenues in that regard. In this paper, we introduce the first fully automatic brain morphometry method based on th...

An open question in neuroimaging is how to develop anatomical brain atlases for the analy- sis of functional data. Here, we present a cortical parcellation model based on macroanatomical infor- mation and test its validity on visuomotor-related cortical functional networks. The parcellation model is based on a recently developed cortical parameteri...

When spatially normalizing images of the human cerebral cortex, the folding pattern is often used as a proxy for architecture. However, the variability of the folding pattern across individuals creates a lot of difficulties. Furthermore, the mechanisms underlying gyrification are still under exploration, and the links between folding and architectu...

Background: Recent neuroimaging studies suggest that autism spectrum disorder results from abnormalities in the cortical folding pattern. Usual morphometric measurements have failed to provide reliable neuroanatomic markers. Here, we propose that sulcal pits, which are the deepest points in each fold, are suitable candidates to uncover this atypic...

This article contains data related to the research article Auzias et al. (2015) [1]. This data can be used as a benchmark for quantitative evaluation of sulcal pits extraction algorithm. In particular, it allows a quantitative comparison with our method, and the assessment of the consistency of the sulcal pits extraction across two well-matched pop...

In this work, we propose a fast and simple approach to obtain a spherical parameterization of a certain class of closed surfaces without holes. Our approach relies on empirical findings that can be mathematically investigated, to a certain extent, by using Laplace-Beltrami Operator and associated geometrical tools. The mapping proposed here is defi...

The hypothalamus is a brain structure containing multiple nuclei that mediate essential behavioral, autonomic, and endocrine functions including oxytocin synthesis. Oxytocin is a neuropeptide linked to complex social cognition and behaviors necessary for an effective social interaction. Oxytocinergic system dysfunction has been linked to social def...

Pooling data acquired on different MR scanners is a commonly used practice to increase the statistical power of studies based on MRI-derived measurements. Such studies are very appealing since they should make it possible to detect more subtle effects related to pathologies. However, the influence of confounds introduced by scanner-related variatio...

Studying cortical anatomy by examining the deepest part of cortical sulci, the sulcal pits, has recently raised a growing interest. In particular, constructing structural representations from patterns of pits has proved a promising approach. This study follows up in this direction and brings two main contri-butions. First, we introduce a graph kern...

Surface-based analysis is a tool of choice to study the anatomy and function of the cortex in adult and children brains. Common surface registration approaches are not adaptable to fetal data since data-driven mapping techniques are limited by the lack of structural features across all ges-tational ages. In this work, we adapt the HIP-HOP model-dri...

Many neuroimaging studies are based on the idea that there are distinct brain regions that are functionally or micro-anatomically homogeneous. Obtaining such regions in an au-tomatic way is a challenging task for fetal data due to the lack of strong and consistent anatomical features at the early stages of brain development. In this paper we propos...

Recent interest has been growing concerning points of maximum depth within folds, the sulcal pits, that can be used as reliable cortical landmarks. These remarkable points on the cortical surface are defined algorithmically as the outcome of an automatic extraction procedure. The influence of several crucial parameters of the reference technique (I...

The cortical surface is composed of a mosaic of distinct regions that are functionally or micro-anatomically homogeneous. Parcellating the cortical surface into few lobes is a common approach in neuroimaging resulting from a long tradition in physiology. However, defining such sub regions consistent across subjects is more difficult. If macro-anato...

In brain imaging, solving learning problems in multi-subjects settings is difficult because of the differences that exist across individuals. Here we introduce a novel classification framework based on group-invariant graphical representations, allowing to overcome the inter-subject variability present in functional magnetic resonance imaging (fMRI...

Autism Spectrum Disorder is associated with an altered early brain development. However, the specific cortical structure abnormalities underlying this disorder remain largely unknown. Here, we designed a multi-modal segmentation pipeline adapted to anatomical MR images acquired in a clinical setting in order to apply state-of-the-art sulcus-based m...

Multi-site studies utilizing MRI-derived measures from multiple scanners present an opportunity to increase the power of statistical models by pooling data. This represents the potential of detecting finer and more subtle effects related to pathology and is thus very appealing. It remains however unclear whether or not the potential confound introd...

Autism Spectrum Disorder is associated with an altered early brain development. However, the specific cortical structure abnormalities underlying this disorder remain largely unknown. Nonetheless, atypical cortical folding provides lingering evidence of early disruptions in neurodevelopmental processes and identifying changes in the geometry of cor...

In the context of inter subject brain surface matching, we present a parameterization of the cortical surface constrained by a model of cortical organization. The parameterization is defined via an harmonic mapping of each hemisphere surface to a rectangular planar domain that integrates a representation of the model. As opposed to previous landmar...

Classification of medical images in multi-subjects settings is a difficult challenge due to the variability that exists between individuals. Here we introduce a new graph-based framework designed to deal with inter-subject functional variability present in fMRI data. A graphical model is constructed to encode the functional, geometric and structura...

In the context of the study of brain morphogenesis, we present here a framework for surface-based group analysis using local cortical features in the neonate brain. We propose to detect and match local maxima from curvature and depth profiles of sulcal fundi. Such entities could have a key role to understand the variability of the brain morphology....

Progress in our understanding of brain functions relies on our capability to explore the human cortical surface at a fine scale (typically 1.5 mm isotropic at 3T). For this purpose, high accuracy is required for all processing steps from image acquisition to data analysis. For group studies, the high intersubject variability of the human cortices h...

This paper describes an automatic procedure for extracting sulcal lines from cortical surface meshes of the human brain, which will serve as a tool for landmark extraction as well as for investigating the morphometry of sulci. The procedure consists in a sequence of steps, including sulcal basin segmentation based on local curvature information, es...

Functional investigation of human hand representation in the motor area M1 requires high resolution functional imaging, to finely separate activation in M1, and a perfect alignment of individual central sulci to improve functional areas overlap and significance of statistical parametric maps obtained from different hand movements. Based on anatomic...

We present a method to automatically detect two new stable anatomical landmarks L(1) and L(2) on the Central Sulcus (CS). Those landmarks are shown to be representative of the Central Sulcus morphology and linked to the functional primary motor area of the hand. Detection is performed after introducing a new morphological characteristic, the sulcal...

The alignment and normalization of individual brain structures is a prerequisite for group-level analyses of structural and functional neuroimaging data. The techniques currently available are either based on volume and/or surface attributes, with limited insight regarding the consistent alignment of anatomical landmarks across individuals. This ar...

Recently, several high dimensional classification methods have been proposed to automatically discriminate between patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI) and elderly controls (CN) based on T1-weighted MRI. However, these methods were assessed on different populations, making it difficult to compare their performan...