Developmental Neuroscience最新文献

Introduction: The underlying neural and/or perceptual mechanisms of different visual illusions are still unknown; thus, they continue to be the focus of many ongoing studies. Inconsistencies persist in the empirical findings for understanding how the perception of these illusions evolves over the course of development.

Methods: We assessed 513 participants between 6.5 and 18.9 years of age, with 103 pairs of illusory and control images spanning five illusion types (Ebbinghaus, Müller-Lyer, Contrast, Moving Snake, and Subjective Contour). Misleading and helpful contexts were added when possible.

Results: In general, we found that, except for the Ebbinghaus illusion, susceptibility changes with age: while for the Müller-Lyer it decreases, for the Contrast, Moving Snake, and Kanizsa, susceptibility increases. Across all illusory conditions, participants' decision time decreased with age. Context also influenced the performance and choice latency. We also found a gender difference: boys were less susceptible than girls to Contrast and Moving Snake illusions and were faster to answer in Müller-Lyer illusion trials.

Conclusion: The current study found that susceptibility to illusions changes in a manner that is age-specific and, in some cases, sex-specific. The different developmental trajectories of the perception of visual illusions support the idea of the lack of a common neural and/or perceptual process behind them. We can suggest that at least some of the cognitive processes and neural pathways involved develop heterochronically.

Introduction: Upstream stimulating factor 2 (USF2) belongs to basic Helix-Loop-Helix-Leucine zipper transcription factor family, regulating expression of genes involved in immune response or energy metabolism network. Role of USF2 in neuropathic pain was evaluated.

Methods: Mice were intraspinally injected with adenovirus for knockdown of USF2 (Ad-shUSF2) and then subjected to spinal nerve ligation (SNL) to induce neuropathic pain. Distribution and expression of USF2 were detected by western blot and immunofluorescence. Mechanical and thermal pain sensitivity were examined by paw withdrawal thresholds (PWT) and paw withdrawal latency (PWL). Chromatin immunoprecipitation (ChIP) and luciferase activity assays were performed to detect binding ability between USF2 and SNHG5.

Results: The expression of USF2 was elevated and colocalized with astrocytes and microglia in L5 dorsal root ganglion (DRG) of SNL-induced mice. Injection of Ad-shUSF2 attenuated SNL-induced decrease of PWT and PWL in mice. Knockdown of USF2 increased the level of IL-10 but decreased TNF-α, IL-1β, and IL-6 in SNL-induced mice. Silence of USF2 enhanced protein expression of CD206 while reducing expression of CD16 and CD32 in SNL-induced mice. USF2 binds to promoter of SNHG5 and weakens SNL-induced up-regulation of SNHG5. SNHG5 binds to miR-181b-5p, and miR-181b-5p to interact with CXCL5.

Conclusion: Silence of USF2 ameliorated neuropathic pain, suppressed activation of M1 microglia, and inhibited inflammation in SNL-induced mice through regulation of SNHG5/miR-181b-5p/CXCL5 axis. Therefore, USF2/SNHG5/miR-181b-5p/CXCL5 might be a promising target for neuropathic pain. However, the effect of USF2/SNHG5/miR-181b-5p/CXCL5 on neuropathic pain should also be investigated in further research.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication deficits, cognitive dysfunction, and stereotyped repetitive behaviors. Regional volume changes are commonly observed in individuals with ASD. To examine volumetric dysregulation across adolescence, the valproic acid (VPA) model was used to induce ASD-like phenotypes in rats.

Method: Regional volumes were obtained via magnetic resonance imaging at either postnatal day 28 or postnatal day 40 (P40), which correspond to early and late adolescence, respectively.

Results: Consistent with prior research, VPA animals had reduced total brain volume compared to control animals. A novel outcome was that VPA animals had overgrown right hippocampi at P40. Differences in the pattern of development of the anterior cingulate cortex were also observed in VPA animals. Differences for the posterior cingulate were only observed in males, but not females.

Conclusion: These results demonstrate differences in region-specific developmental trajectories between control and VPA animals and suggest that the VPA model may capture regional volume changes consistent with human ASD.

Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication deficits, cognitive dysfunction, and stereotyped repetitive behaviors. Regional volume changes are commonly observed in individuals with ASD. To examine volumetric dysregulation across adolescence, the valproic acid (VPA) model was used to induce ASD-like phenotypes in rats.

Method: Regional volumes were obtained via magnetic resonance imaging at either postnatal day 28 or postnatal day 40 (P40), which correspond to early and late adolescence, respectively.

Results: Consistent with prior research, VPA animals had reduced total brain volume compared to control animals. A novel outcome was that VPA animals had overgrown right hippocampi at P40. Differences in the pattern of development of the anterior cingulate cortex were also observed in VPA animals. Differences for the posterior cingulate were only observed in males, but not females.

Conclusion: These results demonstrate differences in region-specific developmental trajectories between control and VPA animals and suggest that the VPA model may capture regional volume changes consistent with human ASD.

Introduction: Brain cholesterol relies on de novo biosynthesis and is crucial for brain development. Cholesterol synthesis is a complex series of reactions that involves more than twenty enzymes to reach the final product and generates a large number of intermediate sterols along two alternate pathways. This is a highly regulated and oxygen-dependent process and thus sensitive to hypoxia.

Methods: Using the modified Vannucci procedure, a clinically relevant animal model of neonatal hypoxia ischemia (HI), we characterized the profile of cholesterol and its sterol intermediates, along with the key enzymes on the cholesterol synthetic pathway over a time course of 5 days after HI in the postnatal day 10 mouse brain.

Results: Although the total cholesterol levels in the injured cortices appeared to be minimally attenuated at 5 days following HI, there was an overall repression of brain cholesterol biosynthesis. Lanosterol and the downstream sterols in both the Bloch and Kandutsch-Russell (K-R) pathways were consistently reduced for up to 3 days except for desmosterol, which was elevated. Correspondingly, protein expression of the controlling transcription factors sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1 was decreased at early time points (within 6 h), in parallel with the downregulation of several substrate enzymes for up to 5 days post-HI. HMG-CoA reductase (HMGCR), the first rate-limiting enzyme, was upregulated in the first 24 h after HI. The expression of 24-dehydrocholesterol reductase (DHCR24) that catalyzes the last step to produce cholesterol on the Bloch pathway and bridges the Bloch to K-R pathway was also augmented.

Conclusions: Our data suggest perturbed brain cholesterol biosynthesis following neonatal HI. As some sterol intermediates and enzymes have diverse functions in brain development and stress responses other than producing cholesterol, assessment of their dynamic changes after HI is important to understand the lipid responses in rodent HI models and to identify lipid-based targeted therapies in future studies.

Introduction: This study aimed to explore the impact and mechanism of Scutellariae radix (SR), dried root of Scutellaria baicalensis Georgi of Labiatae, on prenatal stress (PS)-induced anxiety-like and depression-like behavior in the offspring in a mouse prenatal stress model.

Methods: The open field test (OFT), tail suspension test (TST), and forced swimming test (FST) were utilized to assess the behavior of the offspring. Histological changes were evaluated using HE staining and Nissl staining. ELISA was employed to detect the levels of related factors in the serum and fetal brains of offspring mice. Immunohistochemistry was used to determine the expressions of doublecortin and neurotrophic factors in the hippocampus, and RT-PCR reflected the expression of factors in the hippocampus and placenta of offspring mice. These various techniques collectively provided insight into the neurodevelopmental status by detecting indicators related to neurodevelopmental status. LC-MS/MS and molecular docking were used to clarify the chemical constituents and the pharmacodynamic components in S. radix.

Results: S. radix ameliorated prenatal stress-induced anxiety-like and depression-like behavior in the offspring. It also alleviated hippocampal neurogenesis impairment caused by prenatal stress and restored abnormal expression of hippocampal glutamate (Glu) and brain-derived neurotrophic factor in the offspring. Additionally, S. radix maintained normal 11β-HSD1 expression in the placenta of prenatal stress mice, ensuring a normal level of glucocorticoids (GCs) and glucocorticoid receptors (GRs) in the fetus. Furthermore, S. radix increased the mRNA expression of GR and 11β-HSD2 while decreasing the mRNA expression of 11β-HSD1, thereby normalizing levels of serum CRH, ACTH, and GC in the offspring. Finally, docking results indicated that baicalein, wogonin, wogonoside, and baicalin exhibited stronger binding ability with the target.

Conclusion: The results of our study indicate that S. radix may have the potential to alleviate prenatal stress-induced anxiety-like and depression-like behaviors in offspring, at least partially through protecting placental barrier function, reversing HPA axis hyperfunction, and ameliorating neurodevelopmental dysfunction.

Background: The fetal brain undergoes a dynamic process of development during gestation, marked by well-orchestrated events such as neuronal proliferation, migration, axonal outgrowth, and dendritic arborization, mainly elucidated through histological studies. Ex vivo magnetic resonance imaging (MRI) has emerged as a useful tool for 3D visualization of the developing fetal brain, serving as a complementary tool to traditional histology.

Summary: In this review, we summarized the commonly employed ex vivo MRI techniques and their advances in fetal brain imaging, and proposed a standard protocol for postmortem fetal brain specimen collection and fixation. We then provided an overview of ex vivo MRI-based studies on the fetal brain.

Key messages: According to our review, ex vivo T1- or T2-weighted structural MRI has contributed to the characterization of the anatomy of transient neuronal proliferative zones, the basal ganglia, and the cortex. Diffusion MRI-related techniques, such as diffusion tensor imaging and tractography, have helped investigate the microstructural patterns of fetal brain tissue, as well as the early emergence and development of neuronal migration pathways and white matter bundles. Ex vivo MRI findings have shown strong histological correlations, supporting the potential of MRI in evaluating the developmental events in the fetal brain. Postmortem MRI examinations have also demonstrated comparable, and in certain cases, superior performance to traditional autopsy in revealing fetal brain abnormalities. In conclusion, ex vivo fetal brain MRI is an invaluable tool that provides unique insights into the early stages of brain development.

Introduction: Pubertal maturation is marked by significant changes in stress-induced hormonal responses mediated by the hypothalamic-pituitary-adrenal (HPA) axis, with prepubertal male and female rats often exhibiting greater HPA reactivity compared to adult males and females. Though the implications of these changes are unclear, elevated stress responsiveness might contribute to the stress-related vulnerabilities often associated with puberty.

Methods: The current experiments sought to determine whether differences in cellular activation, as measured by FOS immunohistochemistry, or excitatory ionotropic glutamate receptor subunit expression, as measured by qRT-PCR, in the paraventricular nucleus (PVN) were associated with these noted pubertal shifts in stress reactivity in male and female rats. As the PVN is the key nucleus responsible for activating the hormonal stress response, we predicted greater cellular activation and higher expression levels of glutamate receptor subunits in the PVN of prepubertal males and females compared to their adult counterparts.

Results: Our FOS data revealed that while prepubertal males showed greater stress-induced activation in the PVN than adult males, prepubertal females showed less activation than adult females. Moreover, many of the NMDA, AMPA, and kainate receptor subunits measured, including Grin1, Grin2b, Gria1, Gria2, Grik1, and Grik2, had higher expression levels in adults, particularly in males.

Conclusions: Though not supporting our initial predictions, these data do indicate that age and stress influence the activation of the PVN and the expression of glutamate receptor subunits important in its function. These data also suggest that the effects of age and stress are different in males and females. Though still far from a clear understanding of what mechanism(s) mediate pubertal shift in stress reactivity, these data add to our growing understanding of how age, stress, and sex influence HPA function.