The perception of motion is an important function of vision. Neural wiring diagrams for extracting directional information have been obtained by connectome reconstruction. Direction selectivity in Drosophila is thought to originate in T4/T5 neurons through integrating inputs with different temporal filtering properties. Through genetic screening based on synaptic distribution, we isolated a new type of TmY neuron, termed TmY-ds, that form reciprocal synaptic connections with T4/T5 neurons. Its neurites responded to grating motion along the four cardinal directions and showed a variety of direction selectivity. Intriguingly, its direction selectivity originated from temporal filtering neurons rather than T4/T5. Genetic silencing and activation experiments showed that TmY-ds neurons are functionally upstream of T4/T5. Our results suggest that direction selectivity is generated in a tripartite circuit formed among these three neurons-temporal filtering, TmY-ds, and T4/T5 neurons, in which TmY-ds plays a role in the enhancement of direction selectivity in T4/T5 neurons.
Animals ; Neurites ; Drosophila ; Neurons ; Connectome

Diffusion tensor imaging technology can provide information on the white matter of the brain, which can be used to explore changes in brain tissue structure, but it lacks the specific description of the microstructure information of brain tissue. The neurite orientation dispersion and density imaging make up for its shortcomings. But in order to accurately estimate the brain microstructure, a large number of diffusion gradients are needed, and the calculation is complex and time-consuming through maximum likelihood fitting. Therefore, this paper proposes a kind of microstructure parameters estimation method based on the proximal gradient network, which further avoids the classic fitting paradigm. The method can accurately estimate the parameters while reducing the number of diffusion gradients, and achieve the purpose of imaging quality better than the neurite orientation dispersion and density imaging model and accelerated microstructure imaging via convex optimization model.
Brain/diagnostic imaging* ; Diffusion Magnetic Resonance Imaging ; Diffusion Tensor Imaging ; Neurites ; White Matter

OBJECTIVE: Synaptic vesicle mobilization and neurite outgrowth regulation molecules were examined in modulation of effects of methylphenidate (MPH) in Spontaneous Hypertensive Rats (SHRs), a model for attention-deficit hyperactivity disorder (ADHD). METHODS: We compared the changes in the protein expression level of Cyclin dependent kinase 5 (Cdk5) and molecular substrates of Cdk5; tropomyosin receptor kinase B (TrkB), syntaxin 1A (STX1A) and synaptosomal-associated protein 25 (SNAP25). Comparisons were made in prefrontal cortex of vehicle (distilled water i.p. for 7 days)-treated SHRs, vehicle-treated Wistar Kyoto Rats (WKYs) and MPH (2 mg/kg i.p. for 7 days) treated SHRs. RESULTS: The Cdk5 level of vehicle-treated SHRs was significantly decreased compared to the Cdk5 level of vehicle-treated WKY rats, but was restored to the expression level of vehicle-treated WKYs in MPH-treated SHR. The ratio of p25/p35 was significantly decreased in MPH-treated SHR compared to vehicle-treated SHR. Moreover, TrkB, STX1A and SNAP25 of vehicle-treated SHRs were significantly decreased compared to vehicle-treated WKY rats, but were restored to the expression level of vehicle-treated WKYs in MPH-treated SHR. CONCLUSION: The results show that Cdk5, TrkB, STX1A, and SNAP25 were involved in the modulation of MPH effects in prefrontal cortex of SHRs and play important role in treatment of ADHD.
Animals ; Cyclin-Dependent Kinase 5 ; Methylphenidate ; Neurites ; Phosphotransferases ; Prefrontal Cortex ; Rats ; Rats, Inbred WKY ; Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins ; Synaptic Vesicles ; Synaptosomal-Associated Protein 25 ; Syntaxin 1 ; Tropomyosin ; Water

Alzheimer's Disease (AD) is a progressive neurodegenerative disease, which is pathologically defined by the accumulation of amyloid plaques and hyper-phosphorylated tau aggregates in the brain. Mitochondrial dysfunction is also a prominent feature in AD, and the extracellular Aβ and phosphorylated tau result in the impaired mitochondrial dynamics. In this study, we generated an induced pluripotent stem cell (iPSC) line from an AD patient with amyloid precursor protein (APP) mutation (Val715Met; APP-V715M) for the first time. We demonstrated that both extracellular and intracellular levels of Aβ were dramatically increased in the APP-V715M iPSC-derived neurons. Furthermore, the APP-V715M iPSC-derived neurons exhibited high expression levels of phosphorylated tau (AT8), which was also detected in the soma and neurites by immunocytochemistry. We next investigated mitochondrial dynamics in the iPSC-derived neurons using Mito-tracker, which showed a significant decrease of anterograde and retrograde velocity in the APP-V715M iPSC-derived neurons. We also found that as the Aβ and tau pathology accumulates, fusion-related protein Mfn1 was decreased, whereas fission-related protein DRP1 was increased in the APP-V715M iPSC-derived neurons, compared with the control group. Taken together, we established the first iPSC line derived from an AD patient carrying APP-V715M mutation and showed that this iPSC-derived neurons exhibited typical AD pathological features, including a distinct mitochondrial dysfunction.
Alzheimer Disease ; Amyloid ; Brain ; Carisoprodol ; Humans ; Immunohistochemistry ; Mitochondrial Dynamics ; Neurites ; Neurodegenerative Diseases ; Neurons ; Pathology ; Plaque, Amyloid ; Pluripotent Stem Cells

Spinal cord injury (SCI) causes axonal damage and demyelination, neural cell death, and comprehensive tissue loss, resulting in devastating neurological dysfunction. Neural stem/progenitor cell (NSPCs) transplantation provides therapeutic benefits for neural repair in SCI, and glial cell line-derived neurotrophic factor (GDNF) has been uncovered to have capability of stimulating axonal regeneration and remyelination after SCI. In this study, to evaluate whether GDNF would augment therapeutic effects of NSPCs for SCI, GDNF-encoding or mock adenoviral vector-transduced human NSPCs (GDNF-or Mock-hNSPCs) were transplanted into the injured thoracic spinal cords of rats at 7 days after SCI. Grafted GDNF-hNSPCs showed robust engraftment, long-term survival, an extensive distribution, and increased differentiation into neurons and oligodendroglial cells. Compared with Mock-hNSPC- and vehicle-injected groups, transplantation of GDNF-hNSPCs significantly reduced lesion volume and glial scar formation, promoted neurite outgrowth, axonal regeneration and myelination, increased Schwann cell migration that contributed to the myelin repair, and improved locomotor recovery. In addition, tract tracing demonstrated that transplantation of GDNF-hNSPCs reduced significantly axonal dieback of the dorsal corticospinal tract (dCST), and increased the levels of dCST collaterals, propriospinal neurons (PSNs), and contacts between dCST collaterals and PSNs in the cervical enlargement over that of the controls. Finally grafted GDNF-hNSPCs substantially reversed the increased expression of voltage-gated sodium channels and neuropeptide Y, and elevated expression of GABA in the injured spinal cord, which are involved in the attenuation of neuropathic pain after SCI. These findings suggest that implantation of GDNF-hNSPCs enhances therapeutic efficiency of hNSPCs-based cell therapy for SCI.
Animals ; Axons ; Cell Death ; Cell Movement ; Cell- and Tissue-Based Therapy ; Cicatrix ; Demyelinating Diseases ; gamma-Aminobutyric Acid ; Glial Cell Line-Derived Neurotrophic Factor ; Humans ; Hyperalgesia ; Myelin Sheath ; Neuralgia ; Neurites ; Neuroglia ; Neurons ; Neuropeptide Y ; Paraplegia ; Pyramidal Tracts ; Rats ; Regeneration ; Spinal Cord Injuries ; Spinal Cord ; Therapeutic Uses ; Transplants ; Voltage-Gated Sodium Channels

Previous studies have shown that the sciatic nerve has neurotrophic activity, and nerve regeneration, differentiation, and axon outgrowth can be modulated by different sciatic nerve preparations. However, numerous animals may have to be sacrificed to obtain enough sciatic nerves to make a sciatic nerve preparation. Some studies have demonstrated that the role of sciatic nerve preparations in neural differentiation depends on the neurotrophins that Schwann cells secrete, and these factors are highly conserved among different species. To reduce the use of experimental animals, in this study, we made a leachate by using the sciatic nerve of cattle and explored its effect on neuronal differentiation of rat PC12 cells (a useful model for studying neuronal differentiation). Results showed the neurite outgrowth of PC12 cells treated with the cattle sciatic nerve leachate for 3, 6, and 9 days was significantly improved, and the expressions of β3-tubulin and microtubule-associated protein 2 (two neuron-specific proteins) were increased. Moreover, the ERK1/2 signaling pathway was activated after PC12 cells were incubated with cattle sciatic nerve leachate for 9 days. Thus, a sciatic nerve leachate obtained from cattle can effectively induce neuronal differentiation of rat PC12 cells via ERK1/2 signaling pathway.
Animals ; Axons ; Cattle ; Microtubule-Associated Proteins ; Nerve Growth Factors ; Nerve Regeneration ; Neurites ; Neurons ; PC12 Cells ; Rats ; Schwann Cells ; Sciatic Nerve

Aucubin is a small compound naturally found in traditional medicinal herbs with primarily anti-inflammatory and protective effects. In the nervous system, aucubin is reported to be neuroprotective by enhancing neuronal survival and inhibiting apoptotic cell death in cultures and disease models. Our previous data, however, suggest that aucubin facilitates neurite elongation in cultured hippocampal neurons and axonal regrowth in regenerating sciatic nerves. Here, we investigated whether aucubin facilitates the differentiation of neural precursor cells (NPCs) into specific types of neurons. In NPCs cultured primarily from the rat embryonic hippocampus, aucubin significantly elevated the number of GAD65/67 immunoreactive cells and the expression of GAD65/67 proteins was upregulated dramatically by more than three-fold at relatively low concentrations of aucubin (0.01 µM to 10 µM). The expression of both NeuN and vGluT1 of NPCs, the markers for neurons and glutamatergic cells, respectively, and the number of vGluT1 immunoreactive cells also increased with higher concentrations of aucubin (1 µM and 10 µM), but the ratio of the increases was largely lower than GAD expression and GAD immunoreactive cells. The GABAergic differentiation of pax6-expressing late NPCs into GABA-producing cells was further supported in cortical NPCs primarily cultured from transgenic mouse brains, which express recombinant GFP under the control of pax6 promoter. The results suggest that aucubin can be developed as a therapeutic candidate for neurodegenerative disorders caused by the loss of inhibitory GABAergic neurons.
Animals ; Axons ; Brain ; Cell Death ; GABAergic Neurons* ; Hippocampus ; Mice ; Mice, Transgenic ; Nervous System ; Neurites ; Neurodegenerative Diseases ; Neurons ; Plants, Medicinal ; Rats ; Sciatic Nerve

Autism spectrum disorders (ASDs) are neurodevelopmental disorders that share behavioral features, the results of numerous studies have suggested that the underlying causes of ASDs are multifactorial. Behavioral and/or neurobiological analyses of ASDs have been performed extensively using a valid model of prenatal exposure to valproic acid (VPA). Abnormal synapse formation resulting from altered neurite outgrowth in neural progenitor cells (NPCs) during embryonic brain development has been observed in both the VPA model and ASD subjects. Although several mechanisms have been suggested, the actual mechanism underlying enhanced neurite outgrowth remains unclear. In this study, we found that VPA enhanced the expression of brain-derived neurotrophic factor (BDNF), particularly mature BDNF (mBDNF), through dual mechanisms. VPA increased the mRNA and protein expression of BDNF by suppressing the nuclear expression of methyl-CpG-binding protein 2 (MeCP2), which is a transcriptional repressor of BDNF. In addition, VPA promoted the expression and activity of the tissue plasminogen activator (tPA), which induces BDNF maturation through proteolytic cleavage. Trichostatin A and sodium butyrate also enhanced tPA activity, but tPA activity was not induced by valpromide, which is a VPA analog that does not induce histone acetylation, indicating that histone acetylation activity was required for tPA regulation. VPA-mediated regulation of BDNF, MeCP2, and tPA was not observed in astrocytes or neurons. Therefore, these results suggested that VPA-induced mBDNF upregulation was associated with the dysregulation of MeCP2 and tPA in developing cortical NPCs.
Acetylation ; Astrocytes ; Autism Spectrum Disorder ; Brain ; Brain-Derived Neurotrophic Factor* ; Butyric Acid ; Histones ; Methyl-CpG-Binding Protein 2 ; Neurites ; Neurodevelopmental Disorders ; Neurons ; RNA, Messenger ; Stem Cells* ; Synapses ; Tissue Plasminogen Activator ; Up-Regulation ; Valproic Acid*

A 62-year-old man presented with a one-year history of word finding difficulty, impaired single word comprehension and personality changes including aggression, apathy and eating change. Brain MRIs showed severe atrophy in the left anterior temporal lobe. The clinical syndromic diagnosis was semantic variant primary progressive aphasia. He died at age 70 of pneumonia. At autopsy, transactive response DNA-binding protein (TDP) immunoreactive long dystrophic neurites were predominantly found in the cerebral cortices, which were compatible with frontotemporal lobar degeneration-TDP type C pathology.
Aggression ; Apathy ; Aphasia, Primary Progressive ; Atrophy ; Autopsy ; Brain ; Cerebral Cortex ; Comprehension ; Diagnosis ; Eating ; Frontotemporal Dementia ; Frontotemporal Lobar Degeneration ; Humans ; Magnetic Resonance Imaging ; Middle Aged ; Neurites ; Pathology ; Pneumonia ; Semantics ; TDP-43 Proteinopathies ; Temporal Lobe

OBJECTIVE: To develop an in vitro model analogous to the environment of traumatic spinal cord injury (SCI), the authors evaluated change of astrogliosis following treatments with kainate and/or scratch, and degree of neurite outgrowth after treatment with a kainate inhibitor. METHODS: Astrocytes were obtained from the rat spinal cord. Then, 99% of the cells were confirmed to be GFAP-positive astrocytes. For chemical injury, the cells were treated with kainate at different concentrations (10, 50 or 100 µM). For mechanical injury, two kinds of uniform scratches were made using a plastic pipette tip by removing strips of cells. For combined injury (S/K), scratch and kainate were provided. Cord neurons from rat embryos were plated onto culture plates immediately after the three kinds of injuries and some cultures were treated with a kainate inhibitor. RESULTS: Astro-gliosis (glial fibrillary acidic protein [GFAP], vimentin, chondroitin sulfate proteoglycan [CSPG], rho-associated protein kinase [ROCK], and ephrin type-A receptor 4 [EphA4]) was most prominent after treatment with 50 µM kainate and extensive scratch injury in terms of single arm (p<0.001) and in the S/K-induced injury model in view of single or combination (p<0.001). Neurite outgrowth in the seeded spinal cord (β-III tubulin) was the least in the S/K-induced injury model (p<0.001) and this inhibition was reversed by the kainate inhibitor (p<0.001). CONCLUSION: The current in vitro model combining scratch and kainate induced glial scarring and inhibitory molecules and restricted neurite outgrowth very strongly than either the mechanically or chemically-induced injury model; hence, it may be a useful tool for research on SCI.
Animals ; Arm ; Astrocytes ; Chondroitin Sulfate Proteoglycans ; Cicatrix* ; Embryonic Structures ; In Vitro Techniques ; Kainic Acid* ; Neurites ; Neuroglia ; Neurons ; Plastics ; Protein Kinases ; Rats ; Spinal Cord Injuries ; Spinal Cord* ; Vimentin