Structural Brain Imaging Biomarkers of Autism Spectrum Disorder.

Since the early 1990s, there have literally been thousands of reports related to magnetic resonance imaging of the autistic brain. The goals of these studies have ranged from identifying the earliest biological predictors of an autistic diagnosis to determining brain systems most altered in autistic individuals. Some of the later works attempt to use distinct patterns of brain alterations to help define more homogenous subtypes of autism.

Hyper-focus, sticky attention, and springy attention in young autistic children: Associations with sensory behaviors and cognitive ability.

The autistic-developed monotropism account suggests that atypical, domain-general attentional hyper-focus on interests is a central aspect of autism, but domain-general attention differences in autism can manifest differently. Prior research suggests autistic children are often slow to disengage attention from stimuli-a pattern often called "sticky attention"-and that they can show reduced novelty preference. These attentional patterns could influence sensory experiences and learning.

Sex differences in trajectories of cortical development in autistic children from 2-13 years of age.

Previous studies have reported alterations in cortical thickness in autism. However, few have included enough autistic females to determine if there are sex specific differences in cortical structure in autism. This longitudinal study aimed to investigate autistic sex differences in cortical thickness and trajectory of cortical thinning across childhood.

Improving autism identification and support for individuals assigned female at birth: clinical suggestions and research priorities.

Emerging evidence suggests that the higher prevalence of autism in individuals who are assigned male than assigned female at birth results from both biological factors and identification biases. Autistic individuals who are assigned female at birth (AFAB) and those who are gender diverse experience health disparities and clinical inequity, including late or missed diagnosis and inadequate support. In this Viewpoint, an international panel of clinicians, scientists, and community members with lived experiences of autism reviewed the challenges in identifying autism in individuals who are AFAB and proposed clinical and research directions to promote the health, development, and wellbeing of autistic AFAB individuals.

Why do we need sex-balanced studies of autism?

Males are diagnosed with autism much more frequently than females, and most research study samples reflect this male predominance. The result is that autistic females are understudied. There is a critical need to increase our understanding of autistic females, both biologically and clinically.

Default mode and fronto-parietal network associations with IQ development across childhood in autism.

Background: Intellectual disability affects approximately one third of individuals with autism spectrum disorder (autism). Yet, a major unresolved neurobiological question is what differentiates autistic individuals with and without intellectual disability. Intelligence quotients (IQs) are highly variable during childhood.

Video Game Use, Aggression, and Social Impairment in Adolescents with Autism Spectrum Disorder.

We used parent report data to investigate video game playing, aggression, and social impairment in adolescents with autism spectrum disorder. Parents of autistic adolescents were more likely to report that their child plays video games as a hobby compared to parents of adolescents with typical development and also reported that their children spent more time playing video games. For autistic participants, we found no differences in aggression levels or social impairment when comparing players versus non-players.

Altered Development of Amygdala-Connected Brain Regions in Males and Females with Autism.

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 amygdala, in autism from early to middle childhood. A total of 950 longitudinal structural MRI scans were acquired from 282 children (93 female) with autism and 128 children with typical development (61 female) at up to four time points (mean ages: 39, 52, 64, and 137 months, respectively).

Sex-dependent structure of socioemotional salience, executive control, and default mode networks in preschool-aged children with autism.

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- matched sample of 122 autistic and 122 typically developing (TD) children (2-4 years old) to investigate differences in underlying network structure in preschool-aged autistic children within three large scale intrinsic connectivity networks implicated in ASD: the Socioemotional Salience, Executive Control, and Default Mode Networks.

Association of Amygdala Development With Different Forms of Anxiety in Autism Spectrum Disorder.

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 forms of anxiety and anxieties distinctly related to autism.

The Autism Phenome Project: Toward Identifying Clinically Meaningful Subgroups of Autism.

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 etiologies as well as more targeted interventions and treatments.

Identifying autism symptom severity trajectories across childhood.

An individual's autism symptom severity level can change across childhood. The prevalence and direction of change, however, are still not well understood. Nor are the characteristics of children that experience change.

Examining Associations Between Amygdala Volumes and Anxiety Symptoms in Autism Spectrum Disorder.

Background: Anxiety is one of the most common co-occurring conditions in people with autism spectrum disorder. The amygdala has been identified as being associated with anxiety in populations with and without autism, yet associations in autism were based on relatively small or developmentally constrained samples, leaving questions as to whether these results hold at different developmental ages and in a larger, more robust sample.

Methods: Structural neuroimaging and parent report of anxiety symptoms of children ages 5-13 years with (n = 123) and without (n = 171) a diagnosis of autism were collected from the University of Maryland and three sites from the Autism Brain Imaging Data Exchange.

Activation for newly learned words in left medial-temporal lobe during toddlers' sleep is associated with memory for words.

Little is known about the neural substrates underlying early memory functioning. To gain more insight, we examined how toddlers remember newly learned words. Hippocampal and anterior medial-temporal lobe (MTL) processes have been hypothesized to support forming and retaining the association between novel words and their referents, but direct evidence of this connection in early childhood is lacking.

Longitudinal Evaluation of Cerebral Growth Across Childhood in Boys and Girls With Autism Spectrum Disorder.

Background: Cerebral overgrowth is frequently reported in children but not in adults with autism spectrum disorder (ASD). This suggests that early cerebral overgrowth is followed by normalization of cerebral volumes. However, this notion is predicated on cross-sectional research that is vulnerable to sampling bias.

Fear Potentiated Startle in Children With Autism Spectrum Disorder: Association With Anxiety Symptoms and Amygdala Volume.

Atypical responses to fearful stimuli and the presence of various forms of anxiety are commonly seen in children with autism spectrum disorder (ASD). The fear potentiated startle paradigm (FPS), which has been studied both in relation to anxiety and as a probe for amygdala function, was carried out in 97 children aged 9-14 years including 48 (12 female) with ASD and 49 (14 female) with typical development (TD). In addition, exploratory analyses were conducted examining the association between FPS and amygdala volume as assessed with magnetic resonance imaging in a subset of the children with ASD with or without an anxiety disorder with available MRI data.

A Longitudinal Study of White Matter Development in Relation to Changes in Autism Severity Across Early Childhood.

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. Furthermore, the relationship between altered white matter development and longitudinal changes in autism symptoms is unknown.

Commentary: 'Camouflaging' in autistic people - reflection on Fombonne (2020).

Fombonne's (2020) editorial is a thought-provoking appraisal of the literature on 'camouflaging', whereby some autistic people mask or compensate for their autistic characteristics as an attempt to fit in and to cope with disabilities under neurotypical social norms. Fombonne (2020) highlights three issues of contention: (a) construct validity and measurement of camouflaging; (b) camouflaging as a reason for late autism diagnosis in adolescence/adulthood; and (c) camouflaging as a feature of the 'female autism phenotype'. Here, we argue that (a) establishing construct validity and measurement of different aspects of camouflaging is warranted; (b) subjective experiences are important for the differential diagnosis of autism in adolescence/adulthood; and (c) camouflaging is not necessarily a feature of autism in female individuals - nevertheless, taking into account sex and gender influences in development is crucial to understand behavioural manifestations of autism.

Factor Structure of the Children's Sleep Habits Questionnaire in Young Children with and Without Autism.

The Children's Sleep Habits Questionnaire (CSHQ) is often used to assess sleep in children with autism spectrum disorder (ASD), but little is known about its factor structure in younger children with ASD. We evaluated alternative factor structures and measurement invariance for CSHQ items in 2- to 4-year-olds with ASD or typical development (TD). Bifactor models indicated subscales' variance was subsumed by a general factor predominantly reflecting sleep initiation and nighttime awakening items.

Children with ASD Show Impaired Item-Space Recollection, But Preserved Item-Color Recollection.

Although individuals with autism spectrum disorder (ASD) have been often shown to display similar memory performance on semantic memory tasks compared to typically developing (TD) children, there is ongoing debate about whether and how their ability to remember specific past events (i.e., episodic memory) is impaired.

Eye-Tracking Reveals Absent Repetition Learning Across the Autism Spectrum: Evidence From a Passive Viewing Task.

In the domain of memory, autism is characterized by difficulties in explicitly remembering the specific order of stimuli, whereas implicit serial order memory appears to be preserved. This pattern is of considerable interest because serial order memory is known to play a critical role in children's language development. Currently, however, few paradigms exist that can effectively probe serial order memory across heterogeneous groups of children, including those who are minimally verbal.

Maternal immune conditions are increased in males with autism spectrum disorders and are associated with behavioural and emotional but not cognitive co-morbidity.

Epidemiological and animal research shows that maternal immune activation increases the risk of autism spectrum disorders (ASD) in offspring. Emerging evidence suggests that maternal immune conditions may play a role in the phenotypic expression of neurodevelopmental difficulties in children with ASD and this may be moderated by offspring sex. This study aimed to investigate whether maternal immune conditions were associated with increased severity of adverse neurodevelopmental outcomes in children with ASD.