Frontal-posterior functional imbalance and aberrant function developmental patterns in schizophrenia

Unraveling the Prefrontal Cortex-Basolateral Amygdala Pathway's Role on Schizophrenia's Cognitive Impairments: A Multimodal Study in Patients and Mouse Models

BACKGROUND AND HYPOTHESIS

This study investigated the role of the medial prefrontal cortex (mPFC)-basolateral amygdala (BLA) pathway in schizophrenia (SCZ)-related cognitive impairments using various techniques.

STUDY DESIGN

This study utilized clinical scales, magnetic resonance imaging, single-cell RNA sequencing, and optogenetics to investigate the mPFC-BLA pathway in SCZ patients. In the mouse model, 6-week-old methylazoxymethanol acetate-induced mice demonstrated significant cognitive deficits, which were addressed through stereotaxic injections of an adeno-associated viral vector to unveil the neural connection between the mPFC and BLA.

STUDY RESULTS

Significant disparities in brain volume and neural activity, particularly in the dorsolateral prefrontal cortex (DLPFC) and BLA regions, were found between SCZ patients and healthy controls. Additionally, we observed correlations indicating that reduced volumes of the DLPFC and BLA were associated with lower cognitive function scores. Activation of the mPFC-BLA pathway notably improved cognitive performance in the SCZ model mice, with the targeting of excitatory or inhibitory neurons alone failing to replicate this effect. Single-cell transcriptomic profiling revealed gene expression differences in excitatory and inhibitory neurons in the BLA of SCZ model mice. Notably, genes differentially expressed in the BLA of these model mice were also found in the blood exosomes of SCZ patients.

CONCLUSIONS

Our research provides a comprehensive understanding of the role of the PFC-BLA pathway in SCZ, underscoring its significance in cognitive impairment and offering novel diagnostic and therapeutic avenues. Additionally, our research highlights the potential of blood exosomal mRNAs as noninvasive biomarkers for SCZ diagnosis, underscoring the clinical feasibility and utility of this method.

Repetitive Transcranial Magnetic Stimulation Reversing Abnormal Brain Function in Mood Disorders with Early Life Stress: from preclinical models to clinical applications

BACKGROUND

Early life stress (ELS) significantly increases the risk of mood disorders and affects the neurodevelopment of the primary cortex.

HYPOTHESIS

Modulating the primary cortex through neural intervention can ameliorate the impact of ELS on brain development and consequently alleviate its effects on mood disorders.

METHOD

We induced the chronic unpredictable mild stress (CUMS) model in adolescent rats, followed by applying repetitive transcranial magnetic stimulation (rTMS) to their primary cortex in early adulthood. To assess the applicability of primary cortex rTMS in humans, we recruited individuals aged 17-25 with mood disorders who had experienced ELS and performed primary cortex rTMS on them. Functional magnetic resonance imaging (fMRI) and depression-related behavioral and clinical symptoms were conducted in both rats and human subjects before and after the rTMS.

RESULTS

In animals, fMRI analysis revealed increased activation in the primary cortex of CUMS rats and decrease subcortical activation. Following the intervention of primary cortex rTMS, the abnormal functional activity was reversed. Similarly, in mood disorders patients with ELS, increased activation in the primary cortex and decreased activation in the frontal cortex were observed. During rTMS intervention, similar neuroimaging improvements were noted, particularly decreased activation in the primary cortex. This suggests that targeted rTMS in the primary cortex can reverse the abnormal neuroimaging.

CONCLUSION

This cross-species translational study has identified the primary cortex as a key region in mood disorders patients with ELS. Targeting the primary cortex with rTMS can correct abnormal functional activity while improving symptoms. Our study provides translational evidence for therapeutics targeting the ELS factor of mood disorders patients.

Aberrant Hippocampal Development in Early-onset Mental Disorders and Promising Interventions: Evidence from a Translational Study

Early-onset mental disorders are associated with disrupted neurodevelopmental processes during adolescence. The methylazoxymethanol acetate (MAM) animal model, in which disruption in neurodevelopmental processes is induced, mimics the abnormal neurodevelopment associated with early-onset mental disorders from an etiological perspective. We conducted longitudinal structural magnetic resonance imaging (MRI) scans during childhood, adolescence, and adulthood in MAM rats to identify specific brain regions and critical windows for intervention. Then, the effect of repetitive transcranial magnetic stimulation (rTMS) intervention on the target brain region during the critical window was investigated. In addition, the efficacy of this intervention paradigm was tested in a group of adolescent patients with early-onset mental disorders (diagnosed with major depressive disorder or bipolar disorder) to evaluate its clinical translational potential. The results demonstrated that, compared to the control group, the MAM rats exhibited significantly lower striatal volume from childhood to adulthood (all P <0.001). In contrast, the volume of the hippocampus did not show significant differences during childhood (P >0.05) but was significantly lower than the control group from adolescence to adulthood (both P <0.001). Subsequently, rTMS was applied to the occipital cortex, which is anatomically connected to the hippocampus, in the MAM models during adolescence. The MAM-rTMS group showed a significant increase in hippocampal volume compared to the MAM-sham group (P <0.01), while the volume of the striatum remained unchanged (P >0.05). In the clinical trial, adolescents with early-onset mental disorders showed a significant increase in hippocampal volume after rTMS treatment compared to baseline (P <0.01), and these volumetric changes were associated with improvement in depressive symptoms (r = - 0.524, P = 0.018). These findings highlight the potential of targeting aberrant hippocampal development during adolescence as a viable intervention for early-onset mental disorders with neurodevelopmental etiology as well as the promise of rTMS as a therapeutic approach for mitigating aberrant neurodevelopmental processes and alleviating clinical symptoms.

Regional homogeneity as a marker of sensory cortex dysmaturity in preterm infants

Atypical perinatal sensory experience in preterm infants is thought to increase their risk of neurodevelopmental disabilities by altering the development of the sensory cortices. Here, we used resting-state fMRI data from preterm and term-born infants scanned between 32 and 48 weeks post-menstrual age to assess the effect of early ex-utero exposure on sensory cortex development. Specifically, we utilized a measure of local correlated-ness called regional homogeneity (ReHo). First, we demonstrated that the brain-wide distribution of ReHo mirrors the known gradient of cortical maturation. Next, we showed that preterm birth differentially reduces ReHo across the primary sensory cortices. Finally, exploratory analyses showed that the reduction of ReHo in the primary auditory cortex of preterm infants is related to increased risk of autism at 18 months. In sum, we show that local connectivity within sensory cortices has different developmental trajectories, is differentially affected by preterm birth, and may be associated with later neurodevelopment.

Confirmation of pain-related neuromodulation mechanism of Bushen Zhuangjin Decoction on knee osteoarthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Zhuangjin Decoction (BZD) are an herbal compound commonly used to treat osteoarthritis (OA) in China.

AIM OF THE STUDY

This study aimed to verify the mechanism of Bushen Zhuangjin Decoction in relieving the pain of knee osteoarthritis.

MATERIALS AND METHODS

Network pharmacology evaluation was used to discover the potential targets of BZD to relieve pain in KOA. The therapeutic effects of BZD treatment on KOA pain using histomorphology, behavioral assessments, suspension chip analysis, and ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) assays. The functional magnetic resonance imaging was used to explore the effects of BZD treatment on brain function associated to KOA.

RESULTS

Network pharmacological analysis revealed the association between the analgesic effect of BZD on KOA and the pain signaling neurotransmitter 5-HT. Subsequently, we conducted experiments to verify the therapeutic effect of BZD on pain in KOA animal models. Behavioral tests demonstrated that the pain threshold of knee osteoarthritis rats decreased in PWT and PWL, but BZD was able to increase the pain threshold. Histopathological staining indicated thinning of the cartilage layer and sparse trabeculae in the subchondral bone. Suspension chip analysis revealed a significant increase in pro-inflammatory factors of IL-1α, IL-5, IL-12, IL-17A, RANTES, TNF-α and M-CSF in KOA, along with a significant decrease in anti-inflammatory factor of IL-13. However, BZD treatment decreased the expression of pro-inflammatory factors and increased the content of anti-inflammatory factor. UHPLC-MS/MS analysis showed a significant decrease in the serum levels of GABA, E, GSH, Kyn, Met, and VMA in KOA, which were significantly increased by BZD. Conversely, the serum levels of TrpA, TyrA, Spd, and BALa were significantly increased in KOA and significantly decreased by BZD. ELISA and Western blot analysis showed increased expression of subchondral bone pain-related neuropeptides SP, CGRP, TH, NPY, VEGFA, 5-HT3 in KOA, which were decreased in BZD. Functional magnetic resonance imaging demonstrated that BZD exerts its therapeutic effect on KOA by modulating the activity and functional connections of the cortex, hypothalamus, and hippocampus.

CONCLUSIONS

This study confirmed the significant role of pain-related neuromodulation mechanisms in the analgesic therapy of BZD and provides a theoretical foundation for using BZD as a traditional Chinese medical treatment for KOA pain.

A neuroimaging-based precision medicine framework for depression

BACKGROUND

Symptom-based diagnostic criteria of depression leads to notorious heterogeneity and subjectivity.

METHODS

The study was conducted in two stages at two sites: development of a neuroimaging-based subtyping and precise repetitive transcranial magnetic stimulation (rTMS) strategy for depression at Center 1 and its clinical application at Center 2. Center 1 identified depression subtypes and subtype-specific rTMS targets based on amplitude of low frequency fluctuation (ALFF) in a cohort of 238 major depressive disorder patients and 66 healthy controls (HC). Subtypes were identified using a Gaussian Mixture Model, and subtype-specific rTMS targets were selected based on dominant brain regions prominently differentiating depression subtypes from HC. Subsequently, one classifier was employed and 72 hospitalized, depressed youths at Center 2 received two-week precise rTMS. MRI and clinical assessments were obtained at baseline, midpoint, and treatment completion for evaluation.

RESULTS

Two neuroimaging subtypes of depression, archetypal and atypical depression, were identified based on distinct frontal-posterior functional imbalance patterns as measured by ALFF. The dorsomedial prefrontal cortex was identified as the rTMS target for archetypal depression, and the occipital cortex for atypical depression. Following precise rTMS, ALFF alterations were normalized in both archetypal and atypical depressed youths, corresponding with symptom response of 90.00% in archetypal depression and 70.73% in atypical depression.

CONCLUSIONS

A precision medicine framework for depression was developed based on objective neurobiomarkers and implemented with promising results, actualizing a subtyping-treatment-evaluation closed loop in depression. Future randomized controlled trials are warranted.

Abnormal spontaneous brain activity in females with autism spectrum disorders

Objectives

To date, most studies on autism spectrum disorder (ASD) have focused on sample sets that were primarily or entirely composed of males; brain spontaneous activity changes in females remain unclear. The purpose of this study was to explore changes in the brain spontaneous neural activity in females with ASD.

Methods

In this study, resting-state functional magnetic resonance images (rs-fMRI) of 41 females with ASD and 41 typically developing (TD) controls were obtained from the ABDIE database. The amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) of the two groups were calculated to detect the regional brain activity. A two independent sample t-test was used to analyze differences between the ASD and TD groups and a p-value <0.05 was considered statistically significant after false discovery rate (FDR) correction. Pearson correlation analysis was conducted between social responsiveness scale (SRS) scores and the local activity of significantly different brain regions.

Results

Compared with the typically developing (TD) group, the values of ALFF and ReHo were significantly increased in the left superior temporal gyrus (STG), while the values of ReHo were significantly decreased in the left superior frontal gyrus (SFG), left middle occipital gyrus (MOG), bilateral superior parietal lobule (SPL), and bilateral precuneus in the females with ASD group. Correlation analysis showed that the ReHo of the right precuneus was positively correlated to the total SRS, social communication, and autistic mannerisms.

Conclusion

Spontaneous activity changes in females with ASD involved multiple brain regions and were related to clinical characteristics. Our results may provide some help for further exploring the neurobiological mechanism of females with ASD.

Cerebral blood flow characteristics of drug-naïve attention-deficit/hyperactivity disorder with social impairment: Evidence for region-symptom specificity

Background

Social deficits are among the most important functional impairments in attention-deficit/hyperactivity disorder (ADHD). However, the relationship between social impairment and ADHD core symptoms as well as the underlying cerebral blood flow (CBF) characteristics remain unclear.

Methods

A total of 62 ADHD subjects with social deficits (ADHD + SD), 100 ADHD subjects without social deficits (ADHD-SD) and 81 age-matched typically developing controls (TDC) were enrolled. We first examined the correlation between the Social Responsiveness Scale (SRS-1) and ADHD core symptoms (inattention, hyperactivity, and impulsion) and then explored categorical and dimensional ADHD-related regional CBF by arterial spin labeling (ASL). For the categorical analysis, a voxel-based comparison of CBF maps between the ADHD + SD, ADHD-SD, and TDC groups was performed. For the dimensional analysis, the whole-brain voxel-wise correlation between CBF and ADHD symptoms (inattention, hyperactivity/impulsivity, and total scores) was evaluated in three groups. Finally, correlations between the SRS-1 and ADHD-related regional CBF were investigated. We applied Gaussian random field (GRF) for the correction of multiple comparisons in imaging results (voxel-level P < 0.01, and cluster-level P < 0.05).

Results

The clinical characteristics analysis showed that social deficits positively correlated with ADHD core symptoms, especially in social communication and autistic mannerisms domains. In the categorical analysis, we found that CBF in the left middle/inferior temporal gyrus in ADHD groups was higher than TDCs and was negatively correlated with the social motivation scores. Moreover, in dimensional analysis, we found that CBF in the left middle frontal gyrus was negatively correlated with the inattention scores, SRS total scores and autistic mannerisms scores in ADHD + SD subjects.

Conclusion

The present study shows that inattention, hyperactivity, and impulsivity may be responsible for the occurrence of social deficits in ADHD, with autistic traits being another significant contributing factor. Additionally, CBF in the left middle/inferior temporal gyrus and the left middle frontal gyrus might represent the corresponding physiological mechanisms underlying social deficits in ADHD.

Genetic polymorphism and neuroanatomical changes in schizophrenia

The article is a review of the latest meta-analyses regarding the genetic spectrum in schizophrenia, discussing the risks given by the disrupted-in-schizophrenia 1 (DISC1), catechol-O-methyltransferase (COMT), monoamine oxidases-A∕B (MAO-A∕B), glutamic acid decarboxylase 67 (GAD67) and neuregulin 1 (NRG1) genes, and dysbindin-1 protein. The DISC1 polymorphism significantly increases the risk of schizophrenia, as well injuries from the prefrontal cortex that affect connectivity. NRG1 is one of the most important proteins involved. Its polymorphism is associated with the reduction of areas in the corpus callosum, right uncinate, inferior lateral fronto-occipital fascicle, right external capsule, fornix, right optic tract, gyrus. NRG1 and the ErbB4 receptor (tyrosine kinase receptor) are closely related to the N-methyl-D-aspartate receptor (NMDAR) (glutamate receptor). COMT is located on chromosome 22 and together with interleukin-10 (IL-10) have an anti-inflammatory and immunosuppressive function that influences the dopaminergic system. MAO gene methylation has been associated with mental disorders. MAO-A is a risk gene in the onset of schizophrenia, more precisely a certain type of single-nucleotide polymorphism (SNP), at the gene level, is associated with schizophrenia. In schizophrenia, we find deficits of the γ-aminobutyric acid (GABA)ergic neurotransmitter, the dysfunctions being found predominantly at the level of the substantia nigra. In schizophrenia, missing an allele at GAD67, caused by a SNP, has been correlated with decreases in parvalbumin (PV), somatostatin receptor (SSR), and GAD ribonucleic acid (RNA). Resulting in the inability to mature PV and SSR neurons, which has been associated with hyperactivity.