Derek Sayre Andrews

Derek Sayre Andrews
University of California, Davis | UCD · Department of Psychiatry and Behavioral Sciences at the M.I.N.D. Institute

PhD Neuroimaging, MSc Neuroimaging, BA Psychology

About

42
Publications
4,691
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409
Citations
Introduction
As a postdoctoral scholar with the UC Davis MIND institute I am currently working to better understand longitudinal changes in ASD phenotypes, as well as sex differences in ASD. Furthermore, I am interested in developing pattern recognition models to better identify ASD and predict patient outcomes.
Additional affiliations
February 2014 - present
King's College London
Position
  • PhD Student
Description
  • My PhD work involves identifying neuroimaging biomarkers in Autism Spectrum Disorders using machine learning techniques.

Publications

Publications (42)
Article
Atypical cortical organization and reduced integrity of the gray-white matter boundary have been reported by postmortem studies in individuals with autism spectrum disorder (ASD). However, there are no in vivo studies that examine these particular features of cortical organization in ASD. Hence, we used structural magnetic resonance imaging to exam...
Article
Full-text available
Autism spectrum disorder (ASD) is a highly complex neurodevelopmental condition that is accompanied by neuroanatomical differences on the macroscopic and microscopic level. Findings from histological, genetic, and more recently in vivo neuroimaging studies converge in suggesting that neuroanatomical abnormalities, specifically around the gray‐white...
Article
Background Cross-sectional diffusion-weighted magnetic resonance imaging studies suggest that young autistic children have alterations in white matter structure that differ from older autistic individuals. However, it is unclear whether these differences result from atypical neurodevelopment or sampling differences between young and older cohorts....
Article
Full-text available
Background Cerebral overgrowth is frequently reported in children but not adults with autism spectrum disorder (ASD). This suggests that early cerebral over-growth is followed by normalization of cerebral volumes. However, this notion is predicated upon cross-sectional research that is vulnerable to sampling bias. For example, autistic individuals...
Article
Full-text available
Background The amygdala is widely implicated in both anxiety and autism spectrum disorder. However, no studies have investigated the relationship between co-occurring anxiety and longitudinal amygdala development in autism. Here, the authors characterize amygdala development across childhood in autistic children with and without traditional DSM for...
Preprint
Full-text available
Exploration of bias has significant impact on the transparency and applicability of deep learning pipelines in medical settings, yet is so far woefully understudied. In this paper, we consider two separate groups for which training data is only available at differing image resolutions. For group H, available images and labels are at the preferred h...
Article
Altered amygdala development is implicated in the neurobiology of autism, but little is known about the coordinated development of the brain regions directly connected with the amygdala. Here we investigated the volumetric development of an amygdala-connected network, defined as the set of brain regions with monosynaptic connections with the amygda...
Article
The structure of large-scale intrinsic connectivity networks is atypical in adolescents diagnosed with autism spectrum disorder (ASD or autism). However, the degree to which alterations occur in younger children, and whether these differences vary by sex, is unknown. We utilized structural magnetic resonance imaging (MRI) data from a sex- and age-...
Article
Full-text available
Defining reference models for population variation, and the ability to study individual deviations is essential for understanding inter-individual variability and its relation to the onset and progression of medical conditions. In this work, we assembled a reference cohort of neuroimaging data from 82 sites (N=58,836; ages 2-100) and use normative...
Article
Full-text available
One of the most universally accepted facts about autism is that it is heterogenous. Individuals diagnosed with autism spectrum disorder have a wide range of behavioral presentations and a variety of co-occurring medical and mental health conditions. The identification of more homogenous subgroups is likely to lead to a better understanding of etiol...
Preprint
Full-text available
Background: Intellectual disability affects approximately one third of individuals with autism spectrum disorder (autism), yet a major unresolved question remains concerning the neurobiology that differentiates autistic individuals with and without intellectual disability. IQ is highly variable during childhood. We previously identified subgroups o...
Preprint
Full-text available
Defining reference models for population variation, and the ability to study individual deviations is essential for understanding inter-individual variability and its relation to the onset and progression of medical conditions. In this work, we assembled a reference cohort of neuroimaging data from 82 sites (N=58,836; ages 2-100) and use normative...
Article
Full-text available
Background Recent neuroimaging studies have highlighted differences in cerebral maturation in individuals with autism spectrum disorder (ASD) in comparison to typical development. For instance, the contrast of the gray-white matter boundary is decreased in adults with ASD. To determine how gray-white matter boundary integrity relates to early ASD p...
Preprint
Full-text available
Background: Recent neuroimaging studies have highlighted differences in cerebral maturation in individuals with autism spectrum disorder (ASD) in comparison to typical development. For instance, the sharpness of the gray-white matter boundary is decreased in adults with ASD. To determine how the gray-white matter boundary integrity relates to early...
Preprint
Full-text available
Background: Recent neuroimaging studies have highlighted differences in cerebral maturation in individuals with autism spectrum disorder (ASD) in comparison to typical development. For instance, the sharpness of the gray-white matter boundary is decreased in adults with ASD. To determine how the gray-white matter boundary integrity relates to early...
Preprint
Full-text available
Background: Recent neuroimaging studies have highlighted differences in cerebral maturation in individuals with autism spectrum disorder (ASD) in comparison to typical development. For instance, the contrast of the gray-white matter boundary is decreased in adults with ASD. To determine how gray-white matter boundary integrity relates to early ASD...
Article
Full-text available
Background: The core symptoms of autism spectrum disorder (ASD) are widely theorized to result from altered brain connectivity. Diffusion-weighted magnetic resonance imaging (DWI) has been a versatile method for investigating underlying microstructural properties of white matter (WM) in ASD. Despite phenotypic and etiological heterogeneity, DWI st...
Article
Decreases in cortical volume (CV), thickness (CT) and surface area (SA) have been reported in individuals with schizophrenia by in vivo MRI studies. However, there are few studies that examine these cortical measures as potential biomarkers of treatment resistance (TR) and treatment response (NTR) in schizophrenia. This study used structural MRI to...
Article
Full-text available
Background Histological evidence suggests that autism spectrum disorder (ASD) is accompanied by a reduced integrity of the grey-white matter boundary. This has also recently been confirmed by a structural neuroimaging study in vivo reporting significantly reduced grey-white matter tissue contrast (GWC) in adult individuals (18–42 years of age) with...
Article
22q11.2 Deletion Syndrome (22q11.2DS) is a genetic condition associated with a high prevalence of neuropsychiatric conditions that include autism spectrum disorder (ASD). While evidence suggests that clinical phenotypes represent distinct neurodevelopmental outcomes, it remains unknown whether this translates to the level of neurobiology. To fracti...
Article
Full-text available
Increased cortical thickness (CT) has been reported in Down syndrome (DS) during childhood and adolescence, but it remains unclear, which components of the neural architecture underpin these increases and if CT remains altered in adults. Among other factors, differences in CT measures could be driven by reduced tissue contrast between grey and whit...
Chapter
Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficits in social interaction and communication, as well as repetitive and restrictive behaviours. The etiological and phenotypic complexity of ASD has so far hindered the development of clinically useful biomarkers for the condition. Neuroimaging studies have been v...
Article
Atypical cortical organization and reduced integrity of the gray–white matter boundary have been reported by postmortem studies in individuals with autism spectrum disorder (ASD). However, there are no in vivo studies that examine these particular features of cortical organization in ASD. Hence, we used structural magnetic resonance imaging to exam...
Poster
Full-text available
Schizophrenia is a severe psychiatric condition characterized by symptoms such as hallucinations, paranoia, and delusions. Standard treatment for schizophrenia is effective for the majority patients however approximately 33% of patients remain treatment resistant (TR). It has been suggested that the underlying neurobiological mechanism for TR may b...
Article
Importance: Autism spectrum disorder (ASD) is 2 to 5 times more common in male individuals than in female individuals. While the male preponderant prevalence of ASD might partially be explained by sex differences in clinical symptoms, etiological models suggest that the biological male phenotype carries a higher intrinsic risk for ASD than the fema...
Article
Importance: Autism spectrum disorder (ASD) is 2 to 5 times more common in male individuals than in female individuals. While the male preponderant prevalence of ASD might partially be explained by sex differences in clinical symptoms, etiological models suggest that the biological male phenotype carries a higher intrinsic risk for ASD than the fem...
Article
Full-text available
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition, which is accompanied by differences in gray matter neuroanatomy and white matter connectivity. However, it is unknown whether these differences are linked or reflect independent aetiologies. Using a multimodal neuroimaging approach, we therefore examined 51 male adults with A...
Poster
Full-text available
Introduction: Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by deficits in social interaction and communication, and repetitive behaviors and/or stereotyped interests (Wing, 1997). Histology studies have revealed abnormal cell patterning along the boundary between cortical layer VI and underlying white matte...
Article
Full-text available
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition, which is accompanied by differences in gray matter neuroanatomy and white matter connectivity. However, it is unknown whether these differences are linked or reflect independent aetiologies. Using a multimodal neuroimaging approach, we therefore examined 51 male adults with A...
Article
Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions characterized by atypical structural and functional brain connectivity. Complex network analysis has been mainly used to describe altered network-level organization for functional systems and white matter tracts in ASD. However, atypical functional and structural connectiv...
Poster
Background: Evidence suggests that Autism Spectrum Disorder (ASD) is accompanied by neurodevelopmental differences in brain structure and connectivity. More specifically, it is thought that the brain in ASD is over-connected locally, and under-connected globally (Belmonte et al., 2004). While evidence for global under-connectivity is growing (Koshi...
Poster
Full-text available
Background: Voxel-based morphometry (VBM) is a statistical method for identifying regional differences in grey (GM) and white (WM) volumes. VBM investigations of autism spectrum disorder (ASD) have often been confounded by grouping individuals across different bands of the spectrum, periods of development, and/or comparison to inappropriately match...
Article
Full-text available
Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition that is accompanied by an atypical development of brain maturation. So far, brain development has mainly been studied during early childhood in ASD, and using measures of total or lobular brain volume. However, cortical volumetric measures are a product of two distinct biolog...

Projects

Project (1)
Project
Mechanisms underlying treatment resistance in psychosis