BackgroundStudies have confirmed that the thalamus and the primary somatosensory cortex (SI) are associated with cognitive function. These two brain regions are closely related in structure and function. The interactions between SI and the thalamus are of crucial significance for the cognitive process. Patients with major depressive disorder (MDD) have significant cognitive impairment. Based on these observations, we used resting-state functional magnetic resonance imaging (rs-fMRI) to investigate whether there is an abnormality in the SI-thalamic functional connection in MDD. Furthermore, we explored the clinical symptoms related to this abnormality.MethodsWe included 31 patients with first-episode major depressive disorder and 28 age-, gender-, and education-matched healthy controls (HC). The SI-thalamic functional connectivity was compared between the MDD and HC groups. The correlation analyses were performed between areas with abnormal connectivity and clinical characteristics.ResultsCompared with healthy subjects, the MDD patients had enhanced functional connectivity between the thalamus and SI (p < 0.05, corrected). Brain areas with significantly different levels of connectivity had a negative correlation with the Assessment of Neuropsychological Status total score (r = − 0.383, p = 0.033), delayed memory score (r = − 0.376, p = 0.037) and two-digit continuous operation test score (r = − 0.369, p = 0.041) in MDD patients.ConclusionsThese results demonstrate that SI-thalamic functional connectivity is abnormal and associated with the core clinical symptoms in MDD. The SI-thalamic functional connectivity functions as a neurobiological feature and potential biomarker for MDD.

BackgroundMethyl-CpG-binding protein-2 (MeCP2) is a critical regulator for neural development. Either loss- or gain-of-function leads to severe neurodevelopmental disorders, such as Rett syndrome (RTT) and autism spectrum disorder (ASD). We set out to screen for MECP2 mutations in patients of ASD and determine whether these autism-related mutations may compromise the proper function of MeCP2.MethodsWhole-exome sequencing was performed to screen MECP2 and other ASD candidate genes for 120 patients diagnosed with ASD. The parents of patients who were identified with MECP2 mutation were selected for further Sanger sequencing. Each patient accomplished the case report form including general information and clinical scales applied to assess their clinical features. Mouse cortical neurons and HEK-293 cells were cultured and transfected with MeCP2 wild-type (WT) or mutant to examine the function of autism-associated MeCP2 mutants. HEK-293 cells were used to examine the expression of MeCP2 mutant constructs with Western blot. Mouse cortical neurons were used to analyze neurites and axon outgrowth by immunofluorescence experiments.ResultsWe identified three missense mutations of MECP2 from three autism patients by whole-exome sequencing: p.P152L (c.455C>T), p.P376S (c.1162C>T), and p.R294X (c.880C>T). Among these mutations, p.P152L and p.R294X were de novo mutations, whereas p.P376S was inherited maternally. The diagnosis of RTT was excluded in all three autism patients. Abnormalities of dendritic and axonal growth were found after autism-related MeCP2 mutants were expressed in mouse cortical neurons; suggesting that autism-related MECP2 mutations impair the proper development of neurons.ConclusionsOur study identified genetic mutations of the MECP2 gene in autism patients, which were previously considered to be associated primarily with RTT. This finding suggests that loss-of-function mutations of MECP2 may also lead to autism spectrum disorders.Electronic supplementary materialThe online version of this article (doi:10.1186/s13229-017-0157-5) contains supplementary material, which is available to authorized users.

BackgroundMajor depressive disorder (MDD) is a leading psychiatric disorder that has a lack of biomarkers for a diagnosis.PurposeThe objective of this study was to examine the structural and functional change in the precuneus within first-episode drug naive patients with MDD.MethodsThirty-two first episode drug-naive patients with MDD and thirty healthy controls (HCs) were recruited in this study; the structural MRI and fMRI data were collected using the 3.0 T Trio Siemens System. All the patients were interviewed using the HAMD-17.ResultsThe difference between gray matter volume within the two groups was not observed. Results indicated that the low-frequency fluctuations (ALFF), fractional ALFF (fALFF) and regional homogeneity values of the precuneus within first-episode drug-naive patients with MDD were lower than the HCs. In addition, the fALFF value of the MDD was negatively and statistically significantly correlated with the HAMD-17 total score (P<0.05).ConclusionThe current study found abnormal activity of the precuneus at resting state in first-episode drug-naive patients with MDD, indicating that activity within the precuneus may be a potential biomarker for the diagnosis of MDD.

ObjectiveThe microbiota–gut–brain axis, especially the inflammatory pathway, may play a critical role in the pathogenesis of cognitive impairment in major depressive disorder (MDD). However, studies on the microbiota-inflammatory-cognitive function axis in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and explore the correlation between gut microbiota and inflammatory factors, cognitive function in MDD patients.MethodStudy participants included 66 first-episode, drug naïve MDD patients as well as 43 healthy subjects (HCs). The composition of fecal microbiota was evaluated using16S rRNA sequencing and bioinformatics analysis. The cytokines such as hs-CRP, IL-1β, IL-6, IL-10, and TNF-α in peripheral blood were detected via enzyme linked immunosorbent assay (ELISA); assessment of cognitive functions was performed using the Color Trail Test (CTT), The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Stroop Color-Word Test (SCWT).ResultsWe found that compared with HCs, MDD patients had cognitive impairments and showed different α-diversity and β-diversity of gut microbiota composition. LDA effect size (LEfSe) analysis found MDD have higher Deinococcaceae and lower Bacteroidaceae, Turicibacteraceae, Clostridiaceae and Barnesiellaceae at family level. Deinococcus and Odoribacter was higher in the MDD group, however, Bacteroides, Alistipes, Turicibacter, Clostridium, Roseburia, and Enterobacter were lower at genus level. Furthermore, In MDD patients, the Bacteroidaceae and Bacteroides were both positively correlated with hsCRP, CCT1, CCT2. Alistipes was positively correlated with IL-6, Word time, Color time, Word-Color time, Color-Word time and negatively correlated with Delayed Memory, Total score and Standardized score. Turicibacteraceae and Turicibacter were both negatively correlated with IL-1β and IL-6.ConclusionThe present findings confirm that the gut microbiota in MDD patients have altered gut microbes that are closely associated with inflammatory factors and cognitive function in MDD patients.

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PurposeThis study aimed to explore the intelligence profiles of Chinese school-aged boys with high-functioning autism spectrum disorder (HFASD) and attention-deficit/hyperactivity disorder (ADHD). Additionally, differences in intelligence quotient (IQ) between the HFASD group and the ADHD group were examined.Patients and methodsThirty-two boys with HFASD, 58 boys with ADHD, and 39 typically developing (TD) boys aged 6–16 years participated in this study. The ADHD group was divided into subgroups: ADHD-I (predominantly inattentive) and ADHD-C (combined type). (The ADHD-H [hyperactive] group was excluded because of small sample size). The Wechsler Intelligence Scale for Children-IV Chinese version was administered to every participant, and the FSIQ (Full-Scale IQ) score was used as the measure of IQ.ResultsBoth boys with HFASD and ADHD (ADHD-I and ADHD-C) showed impairments in Processing Speed Index and FSIQ, as compared to the TD group. Lower Verbal Comprehension Index scores were found in the ASD and ADHD-I groups. Interestingly, Working Memory Index was only impaired in children with ADHD. Additionally, equivalent Perceptual Reasoning Index (PRI) scores were found among the HFASD, ADHD, and TD groups.ConclusionResults indicated that both children with ADHD and HFASD have difficulty in processing speed, which may be explained by these children having neurodevelopmental disorders. These results also indicated that working memory appears to only be impacted by having ADHD. Children with ASD are known to have language difficulties while children with ADHD typically display working memory deficits; thus, these findings were expected.

BackgroundThis study aimed to explore the resting-state fMRI changes in Chinese boys with low functioning autism spectrum disorder (LFASD) and the correlation with clinical symptoms.MethodsThe current study acquired resting-state fMRI data from 15 Chinese boys with LFASD and 15 typically developing (TD) boys to examine the local brain activity using the regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) indexes; the researchers also examined these measures and their possible relationships with clinical symptoms using the autism behavior checklist.ResultsResults indicated that boys with LFASD exhibited increased ReHo in the right precuneus and inferior parietal gyrus (IPG), increased ALFF in right middle temporal gyrus, angular gyrus and IPG. However, no correlation was found between the ALFF/ReHo score and clinical symptoms in the LFASD group.ConclusionsSome of the brain regions had ReHo/ALFF values that were higher in the boys with LFASD than the TD group and these differentiated brain areas in boys with LFASD were all on the right cerebrum, which supported ‘atypical rightward asymmetry’ in boys with LFASD.

Objective: It is common that major depressive disorder (MDD) is accompanied by gastrointestinal (GI) symptoms. However, few studies have focused on the clinical characteristics and its possible mechanism, while brain gray matter (GM) structure is important in the pathogenesis of GI symptoms. In this study, we aimed to investigate the basic clinical characteristics and regional GM volume changes in MDD accompanied by GI symptoms. Method: Patients with MDD (n=49) and age, gender, and educational level-matched healthy controls (n=30) were recruited. Patients with MDD were divided into two groups based on the GI status: MDD with (n=27) and without (n=22) GI symptoms. The 24-item Hamilton Depression Rating Scale (HAMD) was administered. T1-weighted anatomical images were obtained and analyzed. Correlation analysis was used to identify the possible associations between changed regional GM volume and GI symptoms and depressive symptoms. Results: The HAMD reductive ratio for 2 weeks of treatment in the GI symptoms group was significantly higher than the non-GI symptoms group ( P <0.05). The regional GM volume showed significant differences among the three groups (Gaussian Random Field [GRF] correction, voxel- P <0.01, cluster- P <0.05). Compared with non-GI symptoms group, GI symptoms group exhibited significantly increased GM volume in the left hippocampus, left parahippocampal gyrus, right parahippocampal gyrus; and decreased GM volume in the right middle frontal gyrus, right precentral gyrus, right cuneus, right precuneus, right superior occipital gyrus (GRF correction, voxel- P <0.01, cluster- P <0.05). These altered brain areas were correlated with the GI symptoms, not depressive symptoms. Conclusion: The changed regional brain GM volume in GI-MDD group may be the pathogenesis for the GI symptoms. In addition, the GI symptoms may predict the prognosis of MDD.