Behavioural Brain Research最新文献

The gut microbiota plays a key role in the brain function impairment caused by chronic stress, yet its exact mechanism remains unclear. Many studies have revealed the important role of miR-124 in the central nervous system. Meanwhile, previous studies have indicated that miR-124 may be regulated by chronic stress and gut microbiota. Here, we aimed to explore whether miR-124 serves as a mediator for the impacts of gut microbial dysbiosis on brain function in mice subjected to chronic stress. Repeated daily restraint stress for 4 weeks was used to induce chronic stress in mice. Chronic stress resulted in gut microbial dysbiosis, abnormal behaviors, and a decrease in hippocampal miR-124 levels. Treatment with different probiotic mixtures significantly alleviated the effects of chronic stress on hippocampal miR-124 levels and mouse behaviors. Suppression of hippocampal miR-124 expression reversed the beneficial effects of probiotics on cognitive function, neurogenesis, and related molecular markers in chronically stressed mice. Bioinformatics analysis and qPCR suggested that Ptpn11 might be a target gene for miR-124 in mediating the effects of gut microbial dysbiosis on brain function in these mice. These findings suggest that miR-124 is a pivotal regulator that mediates the detrimental effects of gut microbial dysbiosis on brain function and the subsequent cognitive impairment during chronic stress.

Bipolar disorder is a mood-related disorder, which can be portrayed as extreme shifts in energy, mood, and activity levels which can also be characterized by manic highs and depressive lows that can be often misdiagnosed as unipolar disorder due to primitive diagnostics techniques based on clinical assessments as well as diagnostic complexities arising due to its heterogeneous nature and overlapping symptoms with conditions like schizophrenia. leading to delays in treatment Strong evidence in support of genetic and epigenetic aspects of bipolar disorder, including mechanisms such as compromised hypothalamic-pituitary-adrenal axis, immune-inflammatory imbalances, oxidative stress, and mitochondrial dysfunction are found. Moreover, some previous research has already stated the role of genes like CITED2, NUDT4, and Arl8B in these processes. The primary goal of this study is to investigate the involvement of the genes in exploring and validating their potential as biomarkers for bipolar disorder. In silico tools like MutationTaster, PolyPhen2, SIFT, GTEx, PhenoScanner, and RegulomeDB were used to perform mutational and gene expression analyses. Results revealed potentially dangerous mutations caused in CITED2, NUDT4, and Arl8B, those which can have diverse outcomes. RegulomeDB, GTEx, and PhenoScanner reveal the involvement of these genes in various brain regions highlighting their relevance to bipolar disorder. This analysis suggests the potential utility of CITED2, NUDT4, and Arl8B as diagnostic markers hence shedding light on their roles to elaborate the molecular range of bipolar disorder. The study also contributes to providing valuable insights into the genetic and molecular basis of bipolar disorders.

According to the behavioral tagging theory, various stages of fear memory, such as contextual fear conditioning, memory retrieval, and fear extinction, can be facilitated by the exploration of a novel open field (OF). A critical time window of efficacy exists for this process. Novel exploration closely adjacent to weak learning may interfere with the setting of the learning tag, leading to a negative effect. In this mouse study, we consistently showed that exposure to a novel or familiar OF immediately prior to the retention test impaired the retrieval of long-term contextual fear memory. However, OF exposure had no effect on the retrieval of recent or remote cued fear memory or short-term contextual fear memory or the reconsolidation of contextual fear memory. In addition, OF exposure impaired spaced but not massed extinction of contextual fear memory. These results suggest that interfering stimulus may result in the transient forgetting of fear memory; however, temporary loss of fear may lead to retention failure of fear extinction. The results of this study are an important complement to the behavioral tagging theory and may provide new guidance for the treatment of post-traumatic stress disorder.

Heat stress, as an environmental stressor, can lead to temperature dysregulation and neuroinflammation, causing depression and anxiety by disrupting brain physiology and functional connectivity. This study looked at how co-enzyme Q10 (Q10) and vitamin E (Vit E), alone and together, affected heat stress-caused anxiety and depression symptoms and inflammation in male mice. Five groups were utilized in the study: control, heat stress (NS), Q10, Vit E, and the combination group (Q10+Vit E). The mice were subjected for 15 min/day to a temperature of 43°C for 14 consecutive days, followed by daily treatments for two weeks with either normal saline, Q10 (500 mg/kg), Vit E (250 mg/kg), or their combination. The forced swimming test (FST) and tail suspension test (TST) were employed to evaluate despair behavior, whereas the elevated plus maze (EPM) and open field test (OFT) were used to assess anxious behaviors. Subsequently, the animals were sacrificed, and serum corticosterone levels, protein expression of inflammasome-related proteins, and hsp70 gene expression were evaluated in the prefrontal cortex (PFC). The study revealed that treatment with Vit E and Q10, alone or together, provided anxiolytic and antidepressant effects in the heat-stress-subjected animals. Also, giving Vit E and Q10 alone or together greatly lowered serum corticosterone levels. In the PFC, they also lowered the levels of hsp70 mRNA and NF-κB, caspase 1, NLRP3, and IL-1β proteins. It is speculated that treatment with Q10 and Vit E can attenuate heat stress-associated anxious and depressive responses by inhibiting the inflammatory pathways and modulating the hypothalamus-pituitary-adrenal axis.

Hyperbaric oxygen (HBO) exposure has recently been reported to be effective in spatial learning and memory. Additionally, HBO exposure considerably improves performance on motor tasks. These findings suggest that HBO exposure may facilitate motor learning. However, the specific effects of HBO exposure on motor learning remain largely unexplored. The present study aimed to investigate the effects of HBO exposure on motor learning tasks. In the experimental animal models (control n = 8, HBO n = 8), the HBO environment was exposed to 100 % oxygen with the chamber at 2.0 atmosphere absolute (ATA) for 90 min/day for 20 days. The motor learning task was an accelerated rotating bar task (bar width, 3 and 6 cm; rotation speed, 4–40 rpm; acceleration, 0.4, 0.6, and 0.8 rpm/s). The learning task was performed for 3 consecutive days. The HBO group showed a main effect of the day factor on the bar with a width of 6 cm, and significant differences were observed for each day comparison. However, no main effect of the day factor was observed in the control group. Additionally, significant differences were found in the bar with a width of 3 cm for both groups between days 1 and 2 and between days 1 and 3. In conclusion, these findings suggest that HBO exposure has a positive effect on more challenging motor learning tasks.

Central cholinergic system and endocannabinoid, anandamide exhibits anti-compulsive-like behavior in mice. However, the role of the central cholinergic system in the anandamide-induced anti-compulsive-like behavior is still unexplored. Therefore, the present study assessed the role of central cholinergic transmission in the anandamide-induced anti-compulsive activity using a marble-burying behavior (MBB) model in mice. The modulation in the anandamide-induced effect on MBB was evaluated using mice with altered central cholinergic transmission achieved by pretreatment (i.c.v.) with various cholinergic agents like acetylcholine (ACh), acetylcholinesterase inhibitor (AChEI), neostigmine, nicotine, mAChR antagonist, atropine, and nAChR antagonist, mecamylamine. The influence of anandamide treatment on the brain AChE activity was also evaluated. The results revealed that i.c.v. injection of anandamide (10, 20 µg/mouse, i.c.v.) dose-dependently reduced MBB in mice. Moreover, anandamide in all the tested doses inhibited the brain AChE activity indicating the role of an enhanced central cholinergic transmission in its anti-compulsive-like effect . Furthermore, the anti-compulsive-like effect of anandamide (20 µg/mouse, i.c.v.) was found to be enhanced in mice centrally pre-treated with, ACh (0.1 µg/mouse, i.c.v.) or AChEI, neostigmine (0.3 µg/mouse, i.c.v.). In addition, the anandamide-induced anti-compulsive-like effect was significantly increased in mice pre-treated with a low dose of nicotine (0.1 µg/mouse, i.c.v.) while, it was attenuated by the higher dose of nicotine (2 µg/mouse, i.c.v.). On the other hand, the anandamide (20 µg/mouse, i.c.v.) induced anti-compulsive-like effect was found to be diminished in mice pre-treated with mAChR antagonist, atropine (0.1, 0.5 µg/mouse, i.c.v.) and pre-injection of nAChR antagonist, mecamylamine (0.1, 0.5 µg/mouse, i.c.v.) potentiated the anandamide induced anti-compulsive-like response in mice. Thus, the present investigation delineates the modulatory role of an enhanced central cholinergic transmission in the anandamide-induced anti-compulsive-like behavior in mice by inhibition of brain AChE or via muscarinic and nicotinic receptors mediated mechanism.

Glutamatergic alteration is one of the potential mechanisms of depression. However, there is no consensus on whether glutamate metabolism changes affect the myelin structure of depression in mouse models. Glutamate chemical exchange saturation transfer (GluCEST) is a novel and powerful molecular imaging technique that can visualize glutamate distribution. In this study, we used the GluCEST imaging technique to look at glutamate levels in mice under chronic unpredictable mild stress (CUMS) and how they relate to demyelination. The CUMS mice were exposed to different stress factors for 6 weeks. Evaluated of depression in CUMS mice by behavioral tests. MRI scans were then performed, including T2-mapping, GluCEST, and diffusion tensor imaging (DTI) sequences. Brain tissues were collected for Luxol Fast Blue staining and immunofluorescence staining to analyze the changes in the myelin sheath. Artificially sketched regions of interest (ROI) (corpus callosum, hippocampus, and thalamus) were used to calculate the GluCEST value, fractional anisotropy (FA), and T2 value. Compared with the control group, the GluCEST value in the ROIs of CUMS mice significantly decreased. Similarly, the FA value in ROIs was lower in the CUMS group than in the CTRL group, but the T2 value did not differ significantly between the two groups. The histological results showed that ROIs in the CUMS group had demyelination compared with the CTRL group, indicating that DTI was more sensitive than T2 mapping in detecting myelin abnormalities. Furthermore, the GluCEST value in the ROIs correlates positively with the FA value. These findings suggest that altered glutamate metabolism may be one of the important factors leading to demyelination in depression, and GluCEST is expected to serve as an imaging biological marker for the diagnosis of demyelination in depression.

Schizophrenia is a disorder with a higher cognitive decline in early adulthood, causing impaired retention of episodic memories. However, the physiological and behavioral functions that underlie cognitive deficits with a potential mechanism to ameliorate and improve cognitive performance are unknown. In this study, we used the MK-801 neurodevelopmental schizophrenia-like model. Rats were divided into two groups: one received MK-801, and the other received saline for five consecutive days (7–11 postnatal days, PND). We evaluated synaptic plasticity late-LTP and spatial memory consolidation in early adolescence and young adulthood using extracellular field recordings in acute hippocampal slices and the Barnes maze task. Next, we examined D1 receptor (D1R) activation as a mechanism to ameliorate cognitive impairments. Our results suggest that MK-801 neonatal treatment induces impairment in late-LTP expression and deficits in spatial memory retrieval in early adolescence that is maintained until young adulthood. Furthermore, we found that activation of dopamine D1R ameliorates the impairments and promotes a robust expression of late-LTP and an improved performance in the Barnes maze task, suggesting a novel and potential therapeutic role in treating cognitive impairments in schizophrenia.