Familial risk of autism alters subcortical and cerebellar brain anatomy in infants and predicts the emergence of repetitive behaviors in early childhood

Autism spectrum disorder (ASD) is a common neurodevelopmental condition, and infant siblings of children with ASD are at a higher risk of developing autistic traits or an ASD diagnosis, when compared to those with typically developing siblings. Reports of differences in brain anatomy and function in high‐risk infants which predict later autistic behaviors are emerging, but although cerebellar and subcortical brain regions have been frequently implicated in ASD, no high‐risk study has examined these regions. Therefore, in this study, we compared regional MRI volumes across the whole brain in 4–6‐month‐old infants with (high‐risk, n = 24) and without (low‐risk, n = 26) a sibling with ASD. Within the high‐risk group, we also examined whether any regional differences observed were associated with autistic behaviors at 36 months. We found that high‐risk infants had significantly larger cerebellar and subcortical volumes at 4–6‐months of age, relative to low‐risk infants; and that larger volumes in high‐risk infants were linked to more repetitive behaviors at 36 months. Our preliminary observations require replication in longitudinal studies of larger samples. If correct, they suggest that the early subcortex and cerebellum volumes may be predictive biomarkers for childhood repetitive behaviors

An investigation into the functions of the septohippocampal cholinergic system

SIGLEAvailable from British Library Document Supply Centre-DSC:D063873 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The ‘PSILAUT’ protocol:an experimental medicine study of autistic differences in the function of brain serotonin targets of psilocybin

Background: The underlying neurobiology of the complex autism phenotype remains obscure, although accumulating evidence implicates the serotonin system and especially the 5HT2A receptor. However, previous research has largely relied upon association or correlation studies to link differences in serotonin targets to autism. To directly establish that serotonergic signalling is involved in a candidate brain function our approach is to change it and observe a shift in that function. We will use psilocybin as a pharmacological probe of the serotonin system in vivo. We will directly test the hypothesis that serotonergic targets of psilocybin – principally, but not exclusively, 5HT2A receptor pathways—function differently in autistic and non-autistic adults. Methods: The ‘PSILAUT’ “shiftability” study is a case–control study autistic and non-autistic adults. How neural responses ‘shift’ in response to low doses (2 mg and 5 mg) of psilocybin compared to placebo will be examined using multimodal techniques including functional MRI and EEG. Each participant will attend on up to three separate visits with drug or placebo administration in a double-blind and randomized order. Results: This study will provide the first direct evidence that the serotonin targets of psilocybin function differently in the autistic and non-autistic brain. We will also examine individual differences in serotonin system function. Conclusions: This work will inform our understanding of the neurobiology of autism as well as decisions about future clinical trials of psilocybin and/or related compounds including stratification approaches. Trial registration: NCT05651126.</p

GABA_B receptor modulation of visual sensory processing in adults with and without autism spectrum disorder

Sensory atypicalities in autism spectrum disorder (ASD) are thought to arise at least partly from differences in γ-aminobutyric acid (GABA) receptor function. However, the evidence to date has been indirect, arising from correlational studies in patients and preclinical models. Here, we evaluated the role of GABA receptor directly, in 44 adults (n = 19 ASD). Baseline concentration of occipital lobe GABA+ (GABA plus coedited macromolecules) was measured using proton magnetic resonance spectroscopy (1H-MRS). Steady-state visual evoked potential (SSVEP) elicited by a passive visual surround suppression paradigm was compared after double-blind randomized oral administration of placebo or 15 to 30 mg of arbaclofen (STX209), a GABA type B (GABAB) receptor agonist. In the placebo condition, the neurotypical SSVEP response was affected by both the foreground stimuli contrast and background interference (suppression). In ASD, however, all stimuli conditions had equal salience and background suppression of the foreground response was weaker. In the placebo condition, although there was no difference in GABA+ between groups, GABA+ concentration positively correlated with response to maximum foreground contrast during maximum background interference in neurotypicals, but not ASD. In neurotypicals, sensitivity to visual stimuli was disrupted by 30 mg of arbaclofen, whereas in ASD, it was made more "typical" and visual processing differences were abolished. Hence, differences in GABAergic function are fundamental to autistic (visual) sensory neurobiology and are modulated by GABAB activity.</p

Adults with autism spectrum disorder and the criminal justice system:An investigation of prevalence of contact with the criminal justice system, risk factors and sex differences in a specialist assessment service

The behavioural and cognitive difficulties of some adults with autism spectrum disorder (ASD) may increase their risk of contact with the criminal justice system (CJS) as a potential suspect. There has been limited investigation of ASD and offending and available evidence is mixed. A retrospective review was completed of medical records of 1570 adults (17–75 years old) who were referred for an ASD assessment over a 17-year period (April 2003 to February 2020). Of the adults diagnosed with ASD, 23% had previous contact with the CJS. Being male or diagnosed with co-occurring attention-deficit hyperactivity disorder (ADHD) and/or psychotic disorder were risk factors for CJS contact. However, the rates of contact with the CJS or for specific offences in the ASD group were never higher than adults referred to our service but not diagnosed with ASD. We did not include a general population comparison group, therefore cannot say how rates of CJS contact in ASD compare with the general population. Further health services research for adults with ASD is warranted, as modifying the treatable risk factors (i.e. ADHD) could reduce contact with the CJS. In addition, joint working between CJS and mental health services could reduce the risk of adults with ASD having CJS contact. LAY ABSTRACT: There has been growing interest in offending and contact with the criminal justice system (CJS) by people with autism spectrum disorder (ASD). However, it is not clear whether people with ASD offend more than those without ASD. Studies have started to look at whether there are particular offences people with ASD are more likely to commit and whether there are any factors that can affect whether someone comes into contact with the CJS as a potential suspect. This study looked at the patients who attended an ASD diagnostic service over a 17-year period to see the rate of contact with the CJS of those who were diagnosed with ASD and whether there were any particular factors that might increase the risk of CJS contact. Nearly a quarter of the ASD group had some contact with the CJS as a potential suspect. Factors that seemed to increase whether someone with ASD was more likely to have contact with the CJS were being male, being diagnosed with ADHD, and being diagnosed with psychosis. This study is one of the largest studies to investigate the rate of CJS contact as a potential suspect in a sample of adults with ASD in an attempt to give a clearer picture of what might influence someone with ASD to engage in offending behaviour in order to try to see what mental health services can offer to reduce the likelihood of someone with ASD coming into contact with the CJS, for example, treatment for another condition or support

Bridge-building between communities: Imagining the future of biomedical autism research

A paradigm shift of research culture is required to ease perceived tensions between autistic people and the biomedical research community. As a group of autistic and non-autistic scientists and stakeholders, we contend that through participatory research we can reject a deficit-based conceptualisation of autism whilst building a shared vision for a neurodiversity-affirmative biomedical research paradigm