No abstract

Epilepsy is a major risk factor for autism spectrum disorder (ASD) and complicates clinical manifestations and management of ASD significantly. Tuberous sclerosis complex (TSC), caused by TSC1 or TSC2 mutations, is one of the medical conditions most commonly associated with ASD and has become an important model to examine molecular pathways associated with ASD. Previous research showed reversal of autism-like social deficits in Tsc1 and Tsc2 mouse models by mammalian target of rapamycin (mTOR) inhibitors. However, at least 70 % of individuals with TSC also have epilepsy, known to complicate the severity and treatment responsiveness of the behavioural phenotype. No previous study has examined the impact of seizures on neurocognitive reversal by mTOR inhibitors. Adult Tsc2 (Eker)-rats express social deficits similar to Tsc2 mice, with additive social deficits from developmental status epilepticus (DSE). DSE was induced by intraperitoneal injection with kainic acid at post-natal days P7 and P14 (n = 12). The experimental group that modelled TSC pathology carried the Tsc2 (Eker)-mutation and was challenged with DSE. The wild-type controls had not received DSE (n = 10). Four-month-old animals were analysed for social behaviour (T1), then treated three times during 1 week with 1 mg/kg everolimus and finally retested in the post-treatment behavioural analysis (T2). In the experimental group, both social interaction and social cognition were impaired at T1. After treatment at T2, behaviour in the experimental group was indistinguishable from controls. The mTOR inhibitor, everolimus, reversed social deficit behaviours in the Tsc2 haploinsufficiency plus DSE animal model to control levels.

There is evidence that a higher incidence of diverse neurodegenerative diseases is associated with the apolipoprotein E epsilon4 allele (ApoE4). Most recently it has been found that the ApoE4 allele is specifically related to an accelerated hippocampal atrophy in patients with Alzheimer's disease. Therefore, the aim of the present study was to investigate the association between ApoE4 genotypes and brain hippocampal volume reduction in alcoholics by using volumetric high-resolution MR imaging. In the present study, female alcoholics with the ApoE4 genotype were found to have significantly smaller hippocampal volumes than those not carrying an epsilon4 allele (ANOVA, p < 0.05), whereas no differences in hippocampal volume were seen in male alcoholics. Since hippocampal volume reduction is lately discussed to be proportional to brain atrophy, we propose that the alcohol-related brain atrophy in patients suffering from chronic alcoholism, is more pronounced in female carriers of the apoE epsilon4 allele. These findings indicate a genetic disposition for alcohol related brain atrophy in female carrying the ApoE4 genotype, which may also explain why female alcoholics are more susceptible to alcohol-induced brain damage.

Anorexia nervosa (AN) is characterized by a relentless pursuit of thinness, despite serious implications for health and social relations. In a previous study wielding the power of computational psychiatry, we found alterations in learning from negative feedback and in neural activity in the posterior medial frontal cortex (pMFC) in young acutely underweight AN patients (acAN). Here we ask whether these abnormalities are merely a state-related consequence of the illness or whether they might constitute a trait marker predisposing individuals to AN. To address this question, we employed the same reinforcement learning paradigm during fMRI with 31 female former AN patients after complete weight-recovery (recAN) and 31 age-matched healthy volunteers (15-28 years). Participants performed a decision task that required adaptation to changing reward contingencies. Data were analyzed within a hierarchical Gaussian filter model, which captures interindividual variability in feedback learning and decision-making under uncertainty. Similar to acute patients, individuals recovered from AN appear to emphasize negative over positive feedback when updating expectations regarding changing reward-punishment contingencies (difference in learning rate between punished and rewarded trials was increased in recAN: p = .006, d = .70. This behavioral pattern was mirrored in hyperactivation of the pMFC following negative feedback (FWE p , .001). Because the previously observed alterations in acANs are also evident after recovery and do not correlate with state variables like weight, altered feedback learning might be a trait marker of AN. The neural underpinnings of these alterations may lie in the pMFC.

Objectives Schizophrenia is a highly disabling psychiatric disorder with a heterogeneous phenotypic appearance. We aimed to further the understanding of some of the underlying genetics of schizophrenia, using left superior temporal gyrus (STG) gray matter thickness reduction as an endophenoptype in a genome-wide association (GWA) study. Methods Structural magnetic resonance imaging (MRI) and genetic data of the Mind Clinical Imaging Consortium (MCIC) study of schizophrenia were used to analyze the interaction effects between 1,067,955 single nucleotide polymorphisms (SNPs) and disease status on left STG thickness in 126 healthy controls and 113 patients with schizophrenia. We next used a pathway approach to detect underlying pathophysiological pathways that may be related to schizophrenia. Results No SNP by diagnosis interaction effect reached genome-wide significance (5 × 10-8) in our GWA study, but ten SNPs reached p-values less than 10-6. The most prominent pathways included those involved in insulin, calcium, PI3K-Akt and MAPK signaling. Conclusions Our strongest findings in the GWA study and pathway analysis point towards an involvement of glucose metabolism in left STG thickness reduction in patients with schizophrenia only. These results are in line with recently published studies, which showed an increased prevalence of psychosis among patients with metabolic syndrome-related illnesses including diabetes.