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ELife May 2024The nucleus incertus (NI), a conserved hindbrain structure implicated in the stress response, arousal, and memory, is a major site for production of the neuropeptide...
The nucleus incertus (NI), a conserved hindbrain structure implicated in the stress response, arousal, and memory, is a major site for production of the neuropeptide relaxin-3. On the basis of () expression, we identified a neuronal cluster that lies adjacent to () neurons in the zebrafish analogue of the NI. To delineate the characteristics of the and NI neurons, we used CRISPR/Cas9 targeted integration to drive gene expression specifically in each neuronal group, and found that they differ in their efferent and afferent connectivity, spontaneous activity, and functional properties. and NI neurons have widely divergent projection patterns and innervate distinct subregions of the midbrain interpeduncular nucleus (IPN). Whereas neurons are activated more robustly by electric shock, neurons exhibit spontaneous fluctuations in calcium signaling and regulate locomotor activity. Our findings define heterogeneous neurons in the NI and provide new tools to probe its diverse functions.
Topics: Animals; Zebrafish; Neurons; Relaxin; Zebrafish Proteins; Homeodomain Proteins; CRISPR-Cas Systems; Rhombencephalon
PubMed: 38819436
DOI: 10.7554/eLife.89516 -
British Journal of Hospital Medicine... May 2024We present an unusual case of rhomboencephalitis in a young, healthy patient. Although meningitis is usually associated with immunodeficiency, rhomboencephalitis is...
We present an unusual case of rhomboencephalitis in a young, healthy patient. Although meningitis is usually associated with immunodeficiency, rhomboencephalitis is more commonly seen in immunocompetent patients. The wide differential for rhomboencephalitis can create a diagnostic challenge. Without prompt pathogen identification and appropriate antibiotic regimen, central nervous system infections can be fatal. Cerebro-Spinal Fluid (CSF) Polymerase Chain Reaction (PCR) aided a prompt diagnosis and adjustment of therapy to achieve a good patient outcome.
Topics: Humans; Listeria monocytogenes; Immunocompetence; Listeriosis; Anti-Bacterial Agents; Male; Rhombencephalon; Magnetic Resonance Imaging; Meningitis, Listeria; Adult; Encephalitis; Polymerase Chain Reaction
PubMed: 38815971
DOI: 10.12968/hmed.2023.0453 -
Brain Research Sep 2024Traumatic brain injury (TBI) is a complex pathophysiological process that results in a variety of neurotransmitter, behavioral, and cognitive deficits. The locus...
Traumatic brain injury (TBI) is a complex pathophysiological process that results in a variety of neurotransmitter, behavioral, and cognitive deficits. The locus coeruleus-norepinephrine (LC-NE) system is a critical regulator of arousal levels and higher executive processes affected by TBI including attention, working memory, and decision making. LC-NE axon injury and impaired signaling within the prefrontal cortex (PFC) is a potential contributor to the neuropsychiatric symptoms after single, moderate to severe TBI. The majority of TBIs are mild, yet long-term cognitive deficits and increased susceptibility for further injury can accumulate after each repetitive mild TBI. As a potential treatment for restoring cognitive function and daytime sleepiness after injury psychostimulants, including methylphenidate (MPH) that increase levels of NE within the PFC, are being prescribed "off-label". The impact of mild and repetitive mild TBI on the LC-NE system remains limited. Therefore, we determined the extent of LC-NE and arousal dysfunction and response to therapeutic doses of MPH in rats following experimentally induced single and repetitive mild TBI. Microdialysis measures of basal NE efflux from the medial PFC and arousal measures were significantly lower after repetitive mild TBI. Females showed higher baseline PFC-NE efflux than males following single and repetitive mild TBI. In response to MPH challenge, males exhibited a blunted PFC-NE response and persistent arousal levels following repetitive mild TBI. These results provide critical insight into the role of catecholamine system dysfunction associated with cognitive deficits following repeated injury, outcome differences between sex/gender, and lack of success of MPH as an adjunctive therapy to improve cognitive function following injury.
Topics: Animals; Male; Norepinephrine; Female; Rats, Sprague-Dawley; Prefrontal Cortex; Central Nervous System Stimulants; Methylphenidate; Brain Concussion; Rats; Brain Injuries, Traumatic; Locus Coeruleus; Arousal; Microdialysis
PubMed: 38815643
DOI: 10.1016/j.brainres.2024.149040 -
ELife May 2024Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are...
Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are involved in shaping functional properties of the glycinergic synapses, which mediate prominent inhibition in the brainstem and spinal cord. To address these issues, we examined the role of neurexins in a model glycinergic synapse between the principal neuron in the medial nucleus of the trapezoid body (MNTB) and the principal neuron in the lateral superior olive (LSO) in the auditory brainstem. Combining RNAscope with stereotactic injection of AAV-Cre in the MNTB of neurexin1/2/3 conditional triple knockout mice, we showed that MNTB neurons highly express all isoforms of neurexins although their expression levels vary remarkably. Selective ablation of all neurexins in MNTB neurons not only reduced the amplitude but also altered the kinetics of the glycinergic synaptic transmission at LSO neurons. The synaptic dysfunctions primarily resulted from an impaired Ca sensitivity of release and a loosened coupling between voltage-gated Ca channels and synaptic vesicles. Together, our current findings demonstrate that neurexins are essential in controlling the strength and temporal precision of the glycinergic synapse, which therefore corroborates the role of neurexins as key presynaptic organizers in all major types of fast chemical synapses.
Topics: Animals; Mice, Knockout; Glycine; Mice; Trapezoid Body; Synaptic Transmission; Neural Cell Adhesion Molecules; Superior Olivary Complex; Brain Stem; Synapses; Neurons; Cell Adhesion Molecules, Neuronal; Nerve Tissue Proteins; Neurexins; Calcium-Binding Proteins
PubMed: 38814174
DOI: 10.7554/eLife.94315 -
Neuroreport Jul 2024Danshensu, also known as salvianic acid A, is a primary active compound extracted from a traditional Chinese herb Danshen (Salvia miltiorrhiza). While its antioxidative...
Danshensu, also known as salvianic acid A, is a primary active compound extracted from a traditional Chinese herb Danshen (Salvia miltiorrhiza). While its antioxidative and neuroprotective effects are well-documented, the underlying mechanisms are poorly understood. In this study, we sought out to investigate if and how Danshensu modulates neuronal excitability and voltage-gated ionic currents in the central nervous system. We prepared brain slices of the mouse brainstem and performed patch-clamp recording in bushy cells in the anteroventral cochlear nucleus, with or without Danshensu incubation for 1 h. QX-314 was used internally to block Na+ current, while tetraethylammonium and 4-aminopyridine were used to isolate different subtypes of K+ current. We found that Danshensu of 100 μm decreased the input resistance of bushy cells by approximately 60% and shifted the voltage threshold of spiking positively by approximately 7 mV, resulting in significantly reduced excitability. Furthermore, we found this reduced excitability by Danshensu was caused by enhanced voltage-gated K+ currents in these neurons, including both low voltage-activated IK,A, by approximately 100%, and high voltage-activated IK,dr, by approximately 30%. Lastly, we found that the effect of Danshensu on K+ currents was dose-dependent in that no enhancement was found for Danshensu of 50 μm and Danshensu of 200 μm failed to cause significantly more enhancement on K+ currents when compared to that of 100 μm. We found that Danshensu reduced neuronal excitability in the central nervous system by enhancing voltage-gated K+ currents, providing mechanistic support for its neuroprotective effect widely seen in vivo.
Topics: Animals; Mice; Neurons; Lactates; Cochlear Nucleus; Patch-Clamp Techniques; Action Potentials; Male; Potassium Channels; Mice, Inbred C57BL
PubMed: 38813908
DOI: 10.1097/WNR.0000000000002047 -
Turkish Journal of Medical Sciences 2024This study aims to determine the possible embryotoxic effects of propofol on the cerebellum and spinal cord using fertile chicken eggs.
BACKGROUND/AIM
This study aims to determine the possible embryotoxic effects of propofol on the cerebellum and spinal cord using fertile chicken eggs.
MATERIALS AND METHODS
A total of 430 fertile eggs were divided into 5 groups: control, saline, 2.5 mg.kg, 12.5 mg.kg, and 37.5 mg.kg propofol. Injections were made immediately before incubation via the air chamber. On the 15th, 18th, and 21st day of incubation, 6 embryos from each group were evaluated. Serial paraffin sections taken from the cerebellum and spinal cord were stained with hematoxylin-eosin, Kluver-Barrera, toluidine blue, and periodic acid-Schiff's reaction. The outer granular layer and total cortex thickness were measured, and the linear density of the Purkinje cells was determined. The ratios of the substantia grisea surface area to the total surface area of the spinal cord were calculated. The transverse and longitudinal diameters of the canalis centralis were also assessed.
RESULTS
No structural malformation was observed in any embryos examined macroscopically. No significant difference was observed between the groups in terms of development and histologic organization of the cerebellum and spinal cord. However, on the 15th, 18th, and 21st day, the outer granular layer (p < 0.001 for all days) and the total cortex thickness (p < 0.01, p < 0.001, and p < 0.001, respectively) decreased significantly in different propofol dose groups in varying degrees in the cerebellum. Similarly, in the spinal cord, there were significant changes in the ratios of the substantia grisea surface area to the total surface area (p < 0.01 and p < 0.001, respectively).
CONCLUSION
It was concluded that the in-ovo-administered propofol given immediately before incubation has adverse effects on the developing cerebellum and spinal cord. Therefore, it is important for anesthesiologists always to remain vigilant when treating female patients of childbearing age.
Topics: Animals; Propofol; Cerebellum; Spinal Cord; Chick Embryo; Anesthetics, Intravenous
PubMed: 38812654
DOI: 10.55730/1300-0144.5760 -
Current Biology : CB Jun 2024An epidemic of sleep loss currently affects modern societies worldwide and is implicated in numerous physiological disorders, including pain sensitization, although few...
An epidemic of sleep loss currently affects modern societies worldwide and is implicated in numerous physiological disorders, including pain sensitization, although few studies have explored the brain pathways affected by active sleep deprivation (ASD; e.g., due to recreation). Here, we describe a neural circuit responsible for pain sensitization in mice treated with 9-h non-stress ASD. Using a combination of advanced neuroscience methods, we found that ASD stimulates noradrenergic inputs from locus coeruleus (LC) to glutamatergic neurons of the hindlimb primary somatosensory cortex (S1HL). Moreover, artificial inhibition of this LC→S1HL pathway alleviates ASD-induced pain sensitization in mice, while chemogenetic activation of this pathway recapitulates the pain sensitization observed following ASD. Our study thus implicates activation of the LC→S1HL pathway in ASD-induced pain sensitization, expanding our fundamental understanding of the multisystem interplay involved in pain processing.
Topics: Animals; Mice; Sleep Deprivation; Locus Coeruleus; Pain; Somatosensory Cortex; Male; Norepinephrine; Mice, Inbred C57BL; Adrenergic Neurons; Neurons; Neural Pathways
PubMed: 38810638
DOI: 10.1016/j.cub.2024.05.005 -
PLoS Computational Biology May 2024The dorsal (DRN) and median (MRN) raphe are important nuclei involved in similar functions, including mood and sleep, but playing distinct roles. These nuclei have a...
The dorsal (DRN) and median (MRN) raphe are important nuclei involved in similar functions, including mood and sleep, but playing distinct roles. These nuclei have a different composition of neuronal types and set of neuronal connections, which among other factors, determine their neuronal dynamics. Most works characterize the neuronal dynamics using classic measures, such as using the average spiking frequency (FR), the coefficient of variation (CV), and action potential duration (APD). In the current study, to refine the characterization of neuronal firing profiles, we examined the neurons within the raphe nuclei. Through the utilization of nonlinear measures, our objective was to discern the redundancy and complementarity of these measures, particularly in comparison with classic methods. To do this, we analyzed the neuronal basal firing profile in both nuclei of urethane-anesthetized rats using the Shannon entropy (Bins Entropy) of the inter-spike intervals, permutation entropy of ordinal patterns (OP Entropy), and Permutation Lempel-Ziv Complexity (PLZC). Firstly, we found that classic (i.e., FR, CV, and APD) and nonlinear measures fail to distinguish between the dynamics of DRN and MRN neurons, except for the OP Entropy. We also found strong relationships between measures, including the CV with FR, CV with Bins entropy, and FR with PLZC, which imply redundant information. However, APD and OP Entropy have either a weak or no relationship with the rest of the measures tested, suggesting that they provide complementary information to the characterization of the neuronal firing profiles. Secondly, we studied how these measures are affected by the oscillatory properties of the firing patterns, including rhythmicity, bursting patterns, and clock-like behavior. We found that all measures are sensitive to rhythmicity, except for the OP Entropy. Overall, our work highlights OP Entropy as a powerful and useful quantity for the characterization of neuronal discharge patterns.
Topics: Animals; Rats; Action Potentials; Neurons; Nonlinear Dynamics; Models, Neurological; Raphe Nuclei; Male; Computational Biology; Rats, Sprague-Dawley
PubMed: 38805554
DOI: 10.1371/journal.pcbi.1012111 -
Neurorehabilitation and Neural Repair Jul 2024Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological and noninvasive brain stimulation technique that has been proven to be effective in... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological and noninvasive brain stimulation technique that has been proven to be effective in Parkinson's disease (PD). The combination of rTMS and treadmill training improved gait function in PD greater than treadmill training alone.
OBJECTIVE
The aim of our study was to evaluate the combination of a novel high-intensity, short intervention rTMS treatment and a multimodal treatment protocol including of physiotherapy, occupational therapy and language therapy, the so-called Parkinson's Disease Multimodal Complex Treatment (PD-MCT), to improve motor function.
METHODS
In this randomized double-blind sham-controlled trial rTMS with 48 Hz or sham was applied over the cerebellum 3 times a day for 5 consecutive days. Patients were assessed at baseline (V0), after 5 days of treatment (V1), and 4 weeks later (V2). The primary clinical outcome measure was the motor sum-score of the Unified PD Rating Scale (UPDRS), secondary clinical outcomes were quantitative motor tasks.
RESULTS
A total of 36 PD patients were randomly allocated either to rTMS (n = 20) or sham (n = 16), both combined with PD-MCT. rTMS improved the UDPRSIII score comparing baseline and V1 in the treatment group by -8.2 points ( = .004). The 8MW and dynamic posturography remained unchanged in both groups after intervention. Compressing weeks of canonical rTMS protocols into 5 days was effective and well tolerated. rTMS may serve as an add-on therapy for augmenting the multimodal complex treatment of motor symptoms, but seems to be ineffective to treat postural instability.
Topics: Humans; Parkinson Disease; Male; Female; Transcranial Magnetic Stimulation; Aged; Double-Blind Method; Middle Aged; Cerebellum; Combined Modality Therapy; Gait Disorders, Neurologic; Outcome Assessment, Health Care; Treatment Outcome
PubMed: 38804539
DOI: 10.1177/15459683241257518 -
Frontiers in Immunology 2024Cerebellar ataxia is an uncommon and atypical manifestation of anti--methyl-D-aspartate receptor (NMDAR) encephalitis, often accompanied by seizures, psychiatric...
Cerebellar ataxia is an uncommon and atypical manifestation of anti--methyl-D-aspartate receptor (NMDAR) encephalitis, often accompanied by seizures, psychiatric symptoms, and cognitive deficits. Previous cases of isolated brainstem-cerebellar symptoms in patients with anti-NMDAR encephalitis have not been documented. This report presents a case of anti-NMDAR encephalitis in which the patient exhibited cerebellar ataxia, nystagmus, diplopia, positive bilateral pathological signs, and hemiparesthesia with no other accompanying symptoms or signs. The presence of positive CSF anti-NMDAR antibodies further supports the diagnosis. Other autoantibodies were excluded through the use of cell-based assays. Immunotherapy was subsequently administered, leading to a gradual recovery of the patient.
Topics: Humans; Anti-N-Methyl-D-Aspartate Receptor Encephalitis; Brain Stem; Autoantibodies; Female; Cerebellar Ataxia; Cerebellum; Receptors, N-Methyl-D-Aspartate; Adult; Immunotherapy; Male; Magnetic Resonance Imaging
PubMed: 38799430
DOI: 10.3389/fimmu.2024.1388667