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Nan Fang Yi Ke Da Xue Xue Bao = Journal... May 2024To assess the effects of repeated mild traumatic brain injury (rmTBI) in the parietal cortex on neuronal morphology and synaptic plasticity in the medulla oblongata of...
OBJECTIVE
To assess the effects of repeated mild traumatic brain injury (rmTBI) in the parietal cortex on neuronal morphology and synaptic plasticity in the medulla oblongata of mice.
METHODS
Thirty-two male ICR mice were randomly divided into sham operation group (=8) and rmTBI group (=24). The mice in the latter group were subjected to repeated mild impact injury of the parietal cortex by a free-falling object. The mice surviving the injuries were evaluated for neurological deficits using neurological severity scores (NSS), righting reflex test and forced swimming test, and pathological changes of the neuronal cells in the medulla oblongata were observed with HE and Nissl staining. Western blotting and immunofluorescence staining were used to detect the expressions of neuroligin 1(NLG-1) and postsynaptic density protein 95(PSD-95) in the medulla oblongata of the mice that either survived rmTBI or not.
RESULTS
None of the mice in the sham-operated group died, while the mortality rate was 41.67% in rmTBI group. The mice surviving rmTBI showed significantly reduced NSS, delayed recovery of righting reflex, increased immobility time in forced swimming test ( < 0.05), and loss of Nissl bodies; swelling and necrosis were observed in a large number of neurons in the medulla oblongata, where the expression levels of NLG-1 and PSD-95 were significantly downregulated ( < 0.05). The mice that did not survive rmTBI showed distorted and swelling nerve fibers and decreased density of neurons in the medulla oblongina with lowered expression levels of NLG-1 and PSD-95 compared with the mice surviving the injuries ( < 0.01).
CONCLUSION
The structural and functional anomalies of the synapses in the medulla oblongata may contribute to death and neurological impairment following rmTBI in mice.
Topics: Animals; Mice; Medulla Oblongata; Disks Large Homolog 4 Protein; Male; Mice, Inbred ICR; Parietal Lobe; Cell Adhesion Molecules, Neuronal; Neurons; Brain Injuries, Traumatic; Neuronal Plasticity
PubMed: 38862454
DOI: 10.12122/j.issn.1673-4254.2024.05.18 -
ELife Jun 2024A key to motor control is the motor thalamus, where several inputs converge. One excitatory input originates from layer 5 of primary motor cortex (M1), while another...
A key to motor control is the motor thalamus, where several inputs converge. One excitatory input originates from layer 5 of primary motor cortex (M1), while another arises from the deep cerebellar nuclei (Cb). M1 terminals distribute throughout the motor thalamus and overlap with GABAergic inputs from the basal ganglia output nuclei, the internal segment of the globus pallidus (GPi), and substantia nigra pars reticulata (SNr). In contrast, it is thought that Cb and basal ganglia inputs are segregated. Therefore, we hypothesized that one potential function of the GABAergic inputs from basal ganglia is to selectively inhibit, or gate, excitatory signals from M1 in the motor thalamus. Here, we tested this possibility and determined the circuit organization of mouse (both sexes) motor thalamus using an optogenetic strategy in acute slices. First, we demonstrated the presence of a feedforward transthalamic pathway from M1 through motor thalamus. Importantly, we discovered that GABAergic inputs from the GPi and SNr converge onto single motor thalamic cells with excitatory synapses from M1. Separately, we also demonstrate that, perhaps unexpectedly, GABAergic GPi and SNr inputs converge with those from the Cb. We interpret these results to indicate that a role of the basal ganglia is to gate the thalamic transmission of M1 and Cb information to cortex.
Topics: Animals; Motor Cortex; Mice; Basal Ganglia; Thalamus; Male; Female; Cerebellum; Neural Pathways; Optogenetics; GABAergic Neurons; Mice, Inbred C57BL
PubMed: 38856045
DOI: 10.7554/eLife.97489 -
JCI Insight Jun 2024Human cytomegalovirus (HCMV) infection in infants infected in utero can lead to a variety of neurodevelopmental disorders. However, mechanisms underlying altered...
Human cytomegalovirus (HCMV) infection in infants infected in utero can lead to a variety of neurodevelopmental disorders. However, mechanisms underlying altered neurodevelopment in infected infants remain poorly understood. We have previously described a murine model of congenital HCMV infection in which murine CMV (MCMV) spreads hematogenously and establishes a focal infection in all regions of the brain of newborn mice, including the cerebellum. Infection resulted in disruption of cerebellar cortical development characterized by reduced cerebellar size and foliation. This disruption was associated with altered cell cycle progression of the granule cell precursors (GCPs), which are the progenitors that give rise to granule cells (GCs), the most abundant neurons in the cerebellum. In the current study, we have demonstrated that MCMV infection leads to prolonged GCP cell cycle, premature exit from the cell cycle, and reduced numbers of GCs resulting in cerebellar hypoplasia. Treatment with TNF-α neutralizing antibody partially normalized the cell cycle alterations of GCPs and altered cerebellar morphogenesis induced by MCMV infection. Collectively, our results argue that virus-induced inflammation altered the cell cycle of GCPs resulting in a reduced numbers of GCs and cerebellar cortical hypoplasia, thus providing a potential mechanism for altered neurodevelopment in fetuses infected with HCMV.
Topics: Animals; Cytomegalovirus Infections; Mice; Cerebellum; Cell Cycle; Disease Models, Animal; Female; Cytomegalovirus; Neural Stem Cells; Muromegalovirus; Animals, Newborn; Humans; Neurons; Tumor Necrosis Factor-alpha; Developmental Disabilities; Nervous System Malformations
PubMed: 38855871
DOI: 10.1172/jci.insight.175525 -
Cerebral Cortex (New York, N.Y. : 1991) Jun 2024Spinocerebellar ataxia type 3 (SCA3) is primarily characterized by progressive cerebellar degeneration, including gray matter atrophy and disrupted anatomical and...
Spinocerebellar ataxia type 3 (SCA3) is primarily characterized by progressive cerebellar degeneration, including gray matter atrophy and disrupted anatomical and functional connectivity. The alterations of cerebellar white matter structural network in SCA3 and the underlying neurobiological mechanism remain unknown. Using a cohort of 20 patients with SCA3 and 20 healthy controls, we constructed cerebellar structural networks from diffusion MRI and investigated alterations of topological organization. Then, we mapped the alterations with transcriptome data from the Allen Human Brain Atlas to identify possible biological mechanisms for regional selective vulnerability to white matter damage. Compared with healthy controls, SCA3 patients exhibited reduced global and nodal efficiency, along with a widespread decrease in edge strength, particularly affecting edges connected to hub regions. The strength of inter-module connections was lower in SCA3 group and negatively correlated with the Scale for the Assessment and Rating of Ataxia score, International Cooperative Ataxia Rating Scale score, and cytosine-adenine-guanine repeat number. Moreover, the transcriptome-connectome association study identified the expression of genes involved in synapse-related and metabolic biological processes. These findings suggest a mechanism of white matter vulnerability and a potential image biomarker for the disease severity, providing insights into neurodegeneration and pathogenesis in this disease.
Topics: Humans; Male; Female; Cerebellum; Middle Aged; Adult; Connectome; Machado-Joseph Disease; Transcriptome; White Matter; Diffusion Magnetic Resonance Imaging
PubMed: 38850215
DOI: 10.1093/cercor/bhae238 -
Scientific Reports Jun 2024Digital media (DM) takes an increasingly large part of children's time, yet the long-term effect on brain development remains unclear. We investigated how individual...
Digital media (DM) takes an increasingly large part of children's time, yet the long-term effect on brain development remains unclear. We investigated how individual effects of DM use (i.e., using social media, playing video games, or watching television/videos) on the development of the cortex (i.e., global cortical surface area), striatum, and cerebellum in children over 4 years, accounting for both socioeconomic status and genetic predisposition. We used a prospective, multicentre, longitudinal cohort of children from the Adolescent Brain and Cognitive Development Study, aged 9.9 years when entering the study, and who were followed for 4 years. Annually, children reported their DM usage through the Youth Screen Time Survey and underwent brain magnetic resonance imaging scans every 2 years. Quadratic-mixed effect modelling was used to investigate the relationship between individual DM usage and brain development. We found that individual DM usage did not alter the development of cortex or striatum volumes. However, high social media usage was associated with a statistically significant change in the developmental trajectory of cerebellum volumes, and the accumulated effect of high-vs-low social media users on cerebellum volumes over 4 years was only β = - 0.03, which was considered insignificant. Nevertheless, the developmental trend for heavy social media users was accelerated at later time points. This calls for further studies and longer follow-ups on the impact of social media on brain development.
Topics: Humans; Child; Male; Female; Brain; Magnetic Resonance Imaging; Longitudinal Studies; Video Games; Social Media; Prospective Studies; Child Development; Adolescent; Cerebellum
PubMed: 38844772
DOI: 10.1038/s41598-024-63566-y -
Science (New York, N.Y.) Jun 2024In addition to their intrinsic rewarding properties, opioids can also evoke aversive reactions that protect against misuse. Cellular mechanisms that govern the interplay...
In addition to their intrinsic rewarding properties, opioids can also evoke aversive reactions that protect against misuse. Cellular mechanisms that govern the interplay between opioid reward and aversion are poorly understood. We used whole-brain activity mapping in mice to show that neurons in the dorsal peduncular nucleus (DPn) are highly responsive to the opioid oxycodone. Connectomic profiling revealed that DPn neurons innervate the parabrachial nucleus (PBn). Spatial and single-nuclei transcriptomics resolved a population of PBn-projecting pyramidal neurons in the DPn that express μ-opioid receptors (μORs). Disrupting μOR signaling in the DPn switched oxycodone from rewarding to aversive and exacerbated the severity of opioid withdrawal. These findings identify the DPn as a key substrate for the abuse liability of opioids.
Topics: Animals; Male; Mice; Analgesics, Opioid; Connectome; Mice, Inbred C57BL; Neurons; Opioid-Related Disorders; Oxycodone; Parabrachial Nucleus; Prefrontal Cortex; Pyramidal Cells; Receptors, Opioid, mu; Reward; Substance Withdrawal Syndrome; Transcriptome; Avoidance Learning
PubMed: 38843332
DOI: 10.1126/science.adn0886 -
Proceedings of the National Academy of... Jun 2024Punishment such as electric shock or physical discipline employs a mixture of physical pain and emotional distress to induce behavior modification. However, a neural...
Punishment such as electric shock or physical discipline employs a mixture of physical pain and emotional distress to induce behavior modification. However, a neural circuit that produces behavior modification by selectively focusing the emotional component, while bypassing the pain typically induced by peripheral nociceptor activation, is not well studied. Here, we show that genetically silencing the activity of neurons expressing calcitonin gene-related peptide (CGRP) in the parabrachial nucleus blocks the suppression of addictive-like behavior induced by footshock. Furthermore, activating CGRP neurons suppresses not only addictive behavior induced by self-stimulating dopamine neurons but also behavior resulting from self-administering cocaine, without eliciting nocifensive reactions. Moreover, among multiple downstream targets of CGRP neurons, terminal activation of CGRP in the central amygdala is effective, mimicking the results of cell body stimulation. Our results indicate that unlike conventional electric footshock, stimulation of CGRP neurons does not activate peripheral nociceptors but effectively curb addictive behavior.
Topics: Animals; Parabrachial Nucleus; Calcitonin Gene-Related Peptide; Mice; Neurons; Behavior, Addictive; Male; Dopaminergic Neurons; Cocaine; Behavior, Animal
PubMed: 38843183
DOI: 10.1073/pnas.2401929121 -
ENeuro Jun 2024Social behavior is important for our well-being, and its dysfunctions impact several pathological conditions. Although the involvement of glutamate is undeniable, the...
Social behavior is important for our well-being, and its dysfunctions impact several pathological conditions. Although the involvement of glutamate is undeniable, the relevance of vesicular glutamate transporter type 3 (VGluT3), a specific vesicular transporter, in the control of social behavior is not sufficiently explored. Since midbrain median raphe region (MRR) is implicated in social behavior and the nucleus contains high amount of VGluT3+ neurons, we compared the behavior of male VGluT3 knock-out (KO) and VGluT3-Cre mice, the latter after chemogenetic MRR-VGluT3 manipulation. Appropriate control groups were included. Behavioral test battery was used for social behavior (sociability, social discrimination, social interaction, resident intruder test) and possible confounding factors (open field, elevated plus maze, Y-maze tests). Neuronal activation was studied by c-Fos immunohistochemistry. Human relevance was confirmed by VGluT3 gene expression in relevant human brainstem areas. VGluT3 KO mice exhibited increased anxiety, social interest, but also aggressive behavior in anxiogenic environment and impaired social memory. For KO animals, social interaction induced lower cell activation in the anterior cingulate, infralimbic cortex, and medial septum. In turn, excitation of MRR-VGluT3+ neurons was anxiolytic. Inhibition increased social interest 24 h later but decreased mobility and social behavior in aggressive context. Chemogenetic activation increased the number of c-Fos+ neurons only in the MRR. We confirmed the increased anxiety-like behavior and impaired memory of VGluT3 KO strain and revealed increased, but inadequate, social behavior. MRR-VGluT3 neurons regulated mobility and social and anxiety-like behavior in a context-dependent manner. The presence of VGluT3 mRNA on corresponding human brain areas suggests clinical relevance.
Topics: Animals; Male; Social Behavior; Mice, Knockout; Humans; Anxiety; Raphe Nuclei; Mice; Neurons; Mice, Inbred C57BL; Behavior, Animal; Mice, Transgenic; Amino Acid Transport Systems, Acidic; Proto-Oncogene Proteins c-fos; Aggression
PubMed: 38839305
DOI: 10.1523/ENEURO.0332-23.2024 -
BMJ Case Reports Jun 2024Ehlers-Danlos syndrome is a group of connective tissue disorders with 14 subtypes, involving joint hyperlaxity, tissue fragility, hypertensive skin and other systemic...
Ehlers-Danlos syndrome is a group of connective tissue disorders with 14 subtypes, involving joint hyperlaxity, tissue fragility, hypertensive skin and other systemic organs with an incidence of 1 in 1 000 000 worldwide. We report a middle childhood female born of second degree consanguineous marriage with limping gait with muscle weakness, with normal development and IQ. Examination revealed microcornea, distal joint laxity of fingers and wrist, hypotonia and broad-based limping gait. Fracture dislocation right hip was managed by fixation. With the atypical neuroimaging finding of cerebellar vermis hypoplasia, exome sequencing was ordered and confirmed as Ehlers-Danlos syndrome (musculocontractural type-1). Hence, genetic counselling was done and prognosis of the child was explained.
Topics: Female; Humans; Cerebellum; Consanguinity; Developmental Disabilities; Ehlers-Danlos Syndrome; Joint Instability; Nervous System Malformations; Child, Preschool
PubMed: 38834308
DOI: 10.1136/bcr-2023-259350 -
The International Journal of... Jun 2024The NMDA antagonist S-ketamine is gaining increasing use as a rapid-acting antidepressant, although its exact mechanisms of action are still unknown. In this study, we... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The NMDA antagonist S-ketamine is gaining increasing use as a rapid-acting antidepressant, although its exact mechanisms of action are still unknown. In this study, we investigated ketamine in respect to its properties toward central noradrenergic mechanisms and how they influence alertness behavior.
METHODS
We investigated the influence of S-ketamine on the locus coeruleus (LC) brain network in a placebo-controlled, cross-over, 7T functional, pharmacological MRI study in 35 healthy male participants (25.1 ± 4.2 years) in conjunction with the attention network task to measure LC-related alertness behavioral changes.
RESULTS
We could show that acute disruption of the LC alertness network to the thalamus by ketamine is related to a behavioral alertness reduction.
CONCLUSION
The results shed new light on the neural correlates of ketamine beyond the glutamatergic system and underpin a new concept of how it may unfold its antidepressant effects.
Topics: Humans; Ketamine; Locus Coeruleus; Male; Adult; Magnetic Resonance Imaging; Cross-Over Studies; Young Adult; Attention; Excitatory Amino Acid Antagonists; Double-Blind Method; Antidepressive Agents
PubMed: 38833581
DOI: 10.1093/ijnp/pyae022