1
|
Tian T, Li H, Zhang S, Yang M. Characterization of sensory and motor dysfunction and morphological alterations in late stages of type 2 diabetic mice. Front Endocrinol (Lausanne) 2024; 15:1374689. [PMID: 38532899 PMCID: PMC10964478 DOI: 10.3389/fendo.2024.1374689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/28/2024] [Indexed: 03/28/2024] Open
Abstract
Diabetic neuropathy is the most common complication of diabetes and lacks effective treatments. Although sensory dysfunction during the early stages of diabetes has been extensively studied in various animal models, the functional and morphological alterations in sensory and motor systems during late stages of diabetes remain largely unexplored. In the current work, we examined the influence of diabetes on sensory and motor function as well as morphological changes in late stages of diabetes. The obese diabetic Leprdb/db mice (db/db) were used for behavioral assessments and subsequent morphological examinations. The db/db mice exhibited severe sensory and motor behavioral defects at the age of 32 weeks, including significantly higher mechanical withdrawal threshold and thermal latency of hindpaws compared with age-matched nondiabetic control animals. The impaired response to noxious stimuli was mainly associated with the remarkable loss of epidermal sensory fibers, particularly CGRP-positive nociceptive fibers. Unexpectedly, the area of CGRP-positive terminals in the spinal dorsal horn was dramatically increased in diabetic mice, which was presumably associated with microglial activation. In addition, the db/db mice showed significantly more foot slips and took longer time during the beam-walking examination compared with controls. Meanwhile, the running duration in the rotarod test was markedly reduced in db/db mice. The observed sensorimotor deficits and motor dysfunction were largely attributed to abnormal sensory feedback and muscle atrophy as well as attenuated neuromuscular transmission in aged diabetic mice. Morphological analysis of neuromuscular junctions (NMJs) demonstrated partial denervation of NMJs and obvious fragmentation of acetylcholine receptors (AChRs). Intrafusal muscle atrophy and abnormal muscle spindle innervation were also detected in db/db mice. Additionally, the number of VGLUT1-positive excitatory boutons on motor neurons was profoundly increased in aged diabetic mice as compared to controls. Nevertheless, inhibitory synaptic inputs onto motor neurons were similar between the two groups. This excitation-inhibition imbalance in synaptic transmission might be implicated in the disturbed locomotion. Collectively, these results suggest that severe sensory and motor deficits are present in late stages of diabetes. This study contributes to our understanding of mechanisms underlying neurological dysfunction during diabetes progression and helps to identify novel therapeutic interventions for patients with diabetic neuropathy.
Collapse
Affiliation(s)
- Ting Tian
- School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haofeng Li
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
- Cryo-EM Facility Center, Southern University of Science and Technology, Shenzhen, China
| |
Collapse
|
2
|
Bao S, Lei Y. Motor unit activity and synaptic inputs to motoneurons in the caudal part of the injured spinal cord. J Neurophysiol 2024; 131:187-197. [PMID: 38117916 DOI: 10.1152/jn.00178.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 12/07/2023] [Accepted: 12/20/2023] [Indexed: 12/22/2023] Open
Abstract
Spinal cord injury (SCI) disrupts neuronal function below the lesion epicenter, causing disuse muscle atrophy. We investigated motor unit (MU) activity and synaptic inputs to motoneurons in the caudal region of the injured spinal cord. Participants with C4-C7 cervical injuries were studied. The extensor digitorum communis (EDC) muscle, which is mainly innervated by C8, was assessed for disuse muscle atrophy. Using advanced electromyography and signal-processing techniques, we examined the concurrent activation of a substantial population of MUs during force-tracking tasks. We found that in participants with SCI (n = 9), both MU discharge rates and the amplitudes of MU action potentials were significantly lower than in controls (n = 9). After SCI, MUs were recruited in a limited force range as the strength of muscle contractions increased, implying a disruption in the orderly MU recruitment pattern. Coherence analysis revealed reduced synaptic inputs to motoneurons in the delta band (0.5-5 Hz) for participants with SCI, suggesting diminished common synaptic inputs to the EDC muscle. In addition, participants with SCI exhibited greater muscle force variability. Using principal component analysis on low-frequency MU discharge rates, we found that the first common component (FCC) captured the most discharge variability in participants with SCI. The coefficients of variation (CV) of the FCC correlated with force signal CVs, suggesting force variability mainly results from common synaptic inputs to the EDC muscle after SCI. These results advance our understanding of the neurophysiology of disuse muscle atrophy in human SCI, paving the way for therapeutic interventions to restore muscle function.NEW & NOTEWORTHY This study analyzed motor unit (MU) function below the lesion epicenter in patients with spinal cord injury (SCI). We found reduced MU discharge rates and action potential amplitudes in participants with SCI compared with controls. The strength of common synaptic inputs to motoneurons was reduced in patients with SCI, with increased force variability primarily due to low-frequency oscillations of common inputs. This study enhances understanding of neurophysiological and behavioral changes in disuse muscle atrophy post-SCI.
Collapse
Affiliation(s)
- Shancheng Bao
- Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas, United States
| | - Yuming Lei
- Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas, United States
| |
Collapse
|
3
|
Lin KZ, Li L, Ma WY, Yang X, Han ZP, Luo NS, Wang J, Xu FQ. A rabies virus-based toolkit for efficient retrograde labeling and monosynaptic tracing. Neural Regen Res 2023; 18:1827-1833. [PMID: 36751812 PMCID: PMC10154474 DOI: 10.4103/1673-5374.358618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Analyzing the structure and function of the brain's neural network is critical for identifying the working principles of the brain and the mechanisms of brain diseases. Recombinant rabies viral vectors allow for the retrograde labeling of projection neurons and cell type-specific trans-monosynaptic tracing, making these vectors powerful candidates for the dissection of synaptic inputs. Although several attenuated rabies viral vectors have been developed, their application in studies of functional networks is hindered by the long preparation cycle and low yield of these vectors. To overcome these limitations, we developed an improved production system for the rapid rescue and preparation of a high-titer CVS-N2c-ΔG virus. Our results showed that the new CVS-N2c-ΔG-based toolkit performed remarkably: (1) N2cG-coated CVS-N2c-ΔG allowed for efficient retrograde access to projection neurons that were unaddressed by rAAV9-Retro, and the efficiency was six times higher than that of rAAV9-Retro; (2) the trans-monosynaptic efficiency of oG-mediated CVS-N2c-ΔG was 2-3 times higher than that of oG-mediated SAD-B19-ΔG; (3) CVS-N2c-ΔG could delivery modified genes for neural activity monitoring, and the time window during which this was maintained was 3 weeks; and (4) CVS-N2c-ΔG could express sufficient recombinases for efficient transgene recombination. These findings demonstrate that new CVS-N2c-ΔG-based toolkit may serve as a versatile tool for structural and functional studies of neural circuits.
Collapse
Affiliation(s)
- Kun-Zhang Lin
- The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen, Key Laboratory of Quality Control Technology for Virus-Based Therapeutics, Guangdong Provincial Medical Products Administration, Shenzhen, Guangdong Province; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province; China
| | - Lei Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China
| | - Wen-Yu Ma
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xin Yang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China
| | - Zeng-Peng Han
- The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen, Key Laboratory of Quality Control Technology for Virus-Based Therapeutics, Guangdong Provincial Medical Products Administration, Shenzhen, Guangdong Province; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province; University of Chinese Academy of Sciences, Beijing; Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei Province; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, Guangdong Province; Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Neng-Song Luo
- The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen, Key Laboratory of Quality Control Technology for Virus-Based Therapeutics, Guangdong Provincial Medical Products Administration, Shenzhen, Guangdong Province, China.,State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Jie Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Fu-Qiang Xu
- The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen, Key Laboratory of Quality Control Technology for Virus-Based Therapeutics, Guangdong Provincial Medical Products Administration, Shenzhen, Guangdong Province, China.,State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei Province, China.,University of Chinese Academy of Sciences, Beijing, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.,Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, Guangdong Province, China.,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
4
|
Goltash S, Stevens SJ, Topcu E, Bui TV. Changes in synaptic inputs to dI3 INs and MNs after complete transection in adult mice. Front Neural Circuits 2023; 17:1176310. [PMID: 37476398 PMCID: PMC10354275 DOI: 10.3389/fncir.2023.1176310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023] Open
Abstract
Introduction Spinal cord injury (SCI) is a debilitating condition that disrupts the communication between the brain and the spinal cord. Several studies have sought to determine how to revive dormant spinal circuits caudal to the lesion to restore movements in paralyzed patients. So far, recovery levels in human patients have been modest at best. In contrast, animal models of SCI exhibit more recovery of lost function. Previous work from our lab has identified dI3 interneurons as a spinal neuron population central to the recovery of locomotor function in spinalized mice. We seek to determine the changes in the circuitry of dI3 interneurons and motoneurons following SCI in adult mice. Methods After a complete transection of the spinal cord at T9-T11 level in transgenic Isl1:YFP mice and subsequent treadmill training at various time points of recovery following surgery, we examined changes in three key circuits involving dI3 interneurons and motoneurons: (1) Sensory inputs from proprioceptive and cutaneous afferents, (2) Presynaptic inhibition of sensory inputs, and (3) Central excitatory glutamatergic synapses from spinal neurons onto dI3 INs and motoneurons. Furthermore, we examined the possible role of treadmill training on changes in synaptic connectivity to dI3 interneurons and motoneurons. Results Our data suggests that VGLUT1+ inputs to dI3 interneurons decrease transiently or only at later stages after injury, whereas levels of VGLUT1+ remain the same for motoneurons after injury. Levels of VGLUT2+ inputs to dI3 INs and MNs may show transient increases but fall below levels seen in sham-operated mice after a period of time. Levels of presynaptic inhibition to VGLUT1+ inputs to dI3 INs and MNs can rise shortly after SCI, but those increases do not persist. However, levels of presynaptic inhibition to VGLUT1+ inputs never fell below levels observed in sham-operated mice. For some synaptic inputs studied, levels were higher in spinal cord-injured animals that received treadmill training, but these increases were observed only at some time points. Discussion These results suggest remodeling of spinal circuits involving spinal interneurons that have previously been implicated in the recovery of locomotor function after spinal cord injury in mice.
Collapse
|
5
|
Clyburn C, Li MH, Ingram SL, Andresen MC, Habecker BA. Cholinergic collaterals arising from noradrenergic sympathetic neurons in mice. J Physiol 2023; 601:1247-1264. [PMID: 36797985 PMCID: PMC10065914 DOI: 10.1113/jp284059] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/07/2023] [Indexed: 02/18/2023] Open
Abstract
The sympathetic nervous system vitally regulates autonomic functions, including cardiac activity. Postganglionic neurons of the sympathetic chain ganglia relay signals from the central nervous system to autonomic peripheral targets. Disrupting this flow of information often dysregulates organ function and leads to poor health outcomes. Despite the importance of these sympathetic neurons, fundamental aspects of the neurocircuitry within peripheral ganglia remain poorly understood. Conventionally, simple monosynaptic cholinergic pathways from preganglionic neurons are thought to activate postganglionic sympathetic neurons. However, early studies suggested more complex neurocircuits may be present within sympathetic ganglia. The present study recorded synaptic responses in sympathetic stellate ganglia neurons following electrical activation of the pre- and postganglionic nerve trunks and used genetic strategies to assess the presence of collateral projections between postganglionic neurons of the stellate ganglia. Orthograde activation of the preganglionic nerve trunk, T-2, uncovered high jitter synaptic latencies consistent with polysynaptic connections. Pharmacological inhibition of nicotinic acetylcholine receptors with hexamethonium blocked all synaptic events. To confirm that high jitter, polysynaptic events were due to the presence of cholinergic collaterals from postganglionic neurons within the stellate ganglion, we knocked out choline acetyltransferase in adult noradrenergic neurons. This genetic knockout eliminated orthograde high jitter synaptic events and EPSCs evoked by retrograde activation. These findings suggest that cholinergic collateral projections arise from noradrenergic neurons within sympathetic ganglia. Identifying the contributions of collateral excitation to normal physiology and pathophysiology is an important area of future study and may offer novel therapeutic targets for the treatment of autonomic imbalance. KEY POINTS: Electrical stimulation of a preganglionic nerve trunk evoked fast synaptic transmission in stellate ganglion neurons with low and high jitter latencies. Retrograde stimulation of a postganglionic nerve trunk evoked direct, all-or-none action currents and delayed nicotinic EPSCs indistinguishable from orthogradely-evoked EPSCs in stellate neurons. Nicotinic acetylcholine receptor blockade prevented all spontaneous and evoked synaptic activity. Knockout of acetylcholine production in noradrenergic neurons eliminated all retrogradely-evoked EPSCs but did not change retrograde action currents, indicating that noradrenergic neurons have cholinergic collaterals connecting neurons within the stellate ganglion.
Collapse
Affiliation(s)
- Courtney Clyburn
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, USA
| | - Ming-Hua Li
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, USA
| | - Susan L Ingram
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michael C Andresen
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, USA
| | - Beth A Habecker
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, USA
| |
Collapse
|
6
|
Xiao C, Ji YW, Luan YW, Jia T, Yin C, Zhou CY. Differential modulation of subthalamic projection neurons by short-term and long-term electrical stimulation in physiological and parkinsonian conditions. Acta Pharmacol Sin 2022; 43:1928-1939. [PMID: 34880404 PMCID: PMC9343451 DOI: 10.1038/s41401-021-00811-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/31/2021] [Indexed: 11/09/2022] Open
Abstract
The subthalamic nucleus (STN) is one of the best targets for therapeutic deep brain stimulation (DBS) to control motor symptoms in Parkinson's disease. However, the precise circuitry underlying the effects of STN-DBS remains unclear. To understand how electrical stimulation affects STN projection neurons, we used a retrograde viral vector (AAV-retro-hSyn-eGFP) to label STN neurons projecting to the substantia nigra pars reticulata (SNr) (STN-SNr neurons) or the globus pallidus interna (GPi) (STN-GPi neurons) in mice, and performed whole-cell patch-clamp recordings from these projection neurons in ex vivo brain slices. We found that STN-SNr neurons exhibited stronger responses to depolarizing stimulation than STN-GPi neurons. In most STN-SNr and STN-GPi neurons, inhibitory synaptic inputs predominated over excitatory inputs and electrical stimulation at 20-130 Hz inhibited these neurons in the short term; its longer-term effects varied. 6-OHDA lesion of the nigrostriatal dopaminergic pathway significantly reduced inhibitory synaptic inputs in STN-GPi neurons, but did not change synaptic inputs in STN-SNr neurons; it enhanced short-term electrical-stimulation-induced inhibition in STN-SNr neurons but reversed the effect of short-term electrical stimulation on the firing rate in STN-GPi neurons from inhibitory to excitatory; in both STN-SNr and STN-GPi neurons, it increased the inhibition but attenuated the enhancement of firing rate induced by long-term electrical stimulation. Our results suggest that STN-SNr and STN-GPi neurons differ in their synaptic inputs, their responses to electrical stimulation, and their modification under parkinsonian conditions; STN-GPi neurons may play important roles in both the pathophysiology and therapeutic treatment of Parkinson's disease.
Collapse
Affiliation(s)
- Cheng Xiao
- Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China. .,Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004, China. .,NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
| | - Ya-wei Ji
- grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China
| | - Yi-wen Luan
- grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China ,grid.460176.20000 0004 1775 8598Department of Anesthesiology, Wuxi People’s Hospital, Wuxi, 214023 China
| | - Tao Jia
- grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China
| | - Cui Yin
- grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China ,grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004 China ,grid.417303.20000 0000 9927 0537NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China
| | - Chun-yi Zhou
- grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesiology, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China ,grid.417303.20000 0000 9927 0537Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, 221004 China ,grid.417303.20000 0000 9927 0537NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004 China
| |
Collapse
|
7
|
Nawreen N, Baccei ML, Herman JP. Single Prolonged Stress Reduces Intrinsic Excitability and Excitatory Synaptic Drive Onto Pyramidal Neurons in the Infralimbic Prefrontal Cortex of Adult Male Rats. Front Cell Neurosci 2021; 15:705660. [PMID: 34366790 PMCID: PMC8342808 DOI: 10.3389/fncel.2021.705660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/02/2021] [Indexed: 02/05/2023] Open
Abstract
Post-traumatic stress disorder (PTSD) is a chronic, debilitating mental illness marked by abnormal fear responses and deficits in extinction of fear memories. The pathophysiology of PTSD is linked to decreased activation of the ventromedial prefrontal cortex (vmPFC). This study aims to investigate underlying functional changes in synaptic drive and intrinsic excitability of pyramidal neurons in the rodent homolog of the vmPFC, the infralimbic cortex (IL), following exposure to single prolonged stress (SPS), a paradigm that mimics core symptoms of PTSD in rats. Rats were exposed to SPS and allowed 1 week of recovery, following which brain slices containing the PFC were prepared for whole-cell patch clamp recordings from layer V pyramidal neurons in the IL. Our results indicate that SPS reduces spontaneous excitatory synaptic drive to pyramidal neurons. In addition, SPS decreases the intrinsic membrane excitability of IL PFC pyramidal cells, as indicated by an increase in rheobase, decrease in input resistance, hyperpolarization of resting membrane potential, and a reduction in repetitive firing rate. Our results suggest that SPS causes a lasting reduction in PFC activity, supporting a body of evidence linking traumatic stress with prefrontal hypoactivity.
Collapse
Affiliation(s)
- Nawshaba Nawreen
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
- Cincinnati Veterans Affairs Medical Center, Cincinnati, OH, United States
| | - Mark L Baccei
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
- Department of Anesthesiology, Pain Research Center, University of Cincinnati Medical Center, Cincinnati, OH, United States
| | - James P Herman
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
- Cincinnati Veterans Affairs Medical Center, Cincinnati, OH, United States
| |
Collapse
|
8
|
Park H, Yamamoto Y, Tanaka-Yamamoto K. Refinement of Cerebellar Network Organization by Extracellular Signaling During Development. Neuroscience 2021; 462:44-55. [PMID: 32502568 DOI: 10.1016/j.neuroscience.2020.05.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022]
Abstract
The cerebellum forms regular neural network structures consisting of a few major types of neurons, such as Purkinje cells, granule cells, and molecular layer interneurons, and receives two major inputs from climbing fibers and mossy fibers. Its regular structures consist of three well-defined layers, with each type of neuron designated to a specific location and forming specific synaptic connections. During the first few weeks of postnatal development in rodents, the cerebellum goes through dynamic changes via proliferation, migration, differentiation, synaptogenesis, and maturation, to create such a network structure. The development of this organized network structure presumably relies on the communication between developing elements in the network, including not only individual neurons, but also their dendrites, axons, and synapses. Therefore, it is reasonable that extracellular signaling via synaptic transmission, secreted molecules, and cell adhesion molecules, plays important roles in cerebellar network development. Although it is not yet clear as to how overall cerebellar development is orchestrated, there is indeed accumulating lines of evidence that extracellular signaling acts toward the development of individual elements in the cerebellar networks. In this article, we introduce what we have learned from many studies regarding the extracellular signaling required for cerebellar network development, including our recent study suggesting the importance of unbiased synaptic inputs from parallel fibers.
Collapse
|
9
|
Abstract
The auditory midbrain is the critical integration center in the auditory pathway of vertebrates. Synaptic inhibition plays a key role during information processing in the auditory midbrain, and these inhibitory neural circuits are seen in all vertebrates and are likely essential for hearing. Here, we review the structure and function of the inhibitory neural circuits of the auditory midbrain. First, we provide an overview on how these inhibitory circuits are organized within different clades of vertebrates. Next, we focus on recent findings in the mammalian auditory midbrain, the most studied of the vertebrates, and discuss how the mammalian auditory midbrain is functionally coordinated.
Collapse
Affiliation(s)
- Munenori Ono
- Department of Physiology, School of Medicine, Kanazawa Medical University, Uchinada, Japan
| | - Tetsufumi Ito
- Department of Anatomy, School of Medicine, Kanazawa Medical University, Uchinada, Japan
| |
Collapse
|
10
|
Wright NC, Hoseini MS, Yasar TB, Wessel R. Coupling of synaptic inputs to local cortical activity differs among neurons and adapts after stimulus onset. J Neurophysiol 2017; 118:3345-3359. [PMID: 28931610 DOI: 10.1152/jn.00398.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cortical activity contributes significantly to the high variability of sensory responses of interconnected pyramidal neurons, which has crucial implications for sensory coding. Yet, largely because of technical limitations of in vivo intracellular recordings, the coupling of a pyramidal neuron's synaptic inputs to the local cortical activity has evaded full understanding. Here we obtained excitatory synaptic conductance ( g) measurements from putative pyramidal neurons and local field potential (LFP) recordings from adjacent cortical circuits during visual processing in the turtle whole brain ex vivo preparation. We found a range of g-LFP coupling across neurons. Importantly, for a given neuron, g-LFP coupling increased at stimulus onset and then relaxed toward intermediate values during continued visual stimulation. A model network with clustered connectivity and synaptic depression reproduced both the diversity and the dynamics of g-LFP coupling. In conclusion, these results establish a rich dependence of single-neuron responses on anatomical, synaptic, and emergent network properties. NEW & NOTEWORTHY Cortical neurons are strongly influenced by the networks in which they are embedded. To understand sensory processing, we must identify the nature of this influence and its underlying mechanisms. Here we investigate synaptic inputs to cortical neurons, and the nearby local field potential, during visual processing. We find a range of neuron-to-network coupling across cortical neurons. This coupling is dynamically modulated during visual processing via biophysical and emergent network properties.
Collapse
Affiliation(s)
- Nathaniel C Wright
- Department of Physics, Washington University in St. Louis , St. Louis, Missouri
| | - Mahmood S Hoseini
- Department of Physics, Washington University in St. Louis , St. Louis, Missouri
| | - Tansel Baran Yasar
- Department of Physics, Washington University in St. Louis , St. Louis, Missouri
| | - Ralf Wessel
- Department of Physics, Washington University in St. Louis , St. Louis, Missouri
| |
Collapse
|
11
|
Gulyás AI, Freund TF, Káli S. The Effects of Realistic Synaptic Distribution and 3D Geometry on Signal Integration and Extracellular Field Generation of Hippocampal Pyramidal Cells and Inhibitory Neurons. Front Neural Circuits 2016; 10:88. [PMID: 27877113 PMCID: PMC5099150 DOI: 10.3389/fncir.2016.00088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 10/17/2016] [Indexed: 12/02/2022] Open
Abstract
In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In the electrotonically compact parvalbumin- and cholecystokinincontaining interneurons, synaptic events are visible in the whole dendritic arbor, and thus the entire dendritic tree may form a single integrative element. Calretinin-containing interneurons were found to be electrotonically extended, which suggests the possibility of complex dendritic processing in this cell type. Our results also highlight the need for the integration of methods that allow the measurement of dendritic processes into studies of synaptic interactions and dynamics in neural networks.
Collapse
Affiliation(s)
- Attila I Gulyás
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Tamás F Freund
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Szabolcs Káli
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| |
Collapse
|
12
|
Baquero AF, Kirigiti MA, Baquero KC, Lee SJ, Smith MS, Grove KL. Developmental changes in synaptic distribution in arcuate nucleus neurons. J Neurosci 2015; 35:8558-69. [PMID: 26041922 DOI: 10.1523/JNEUROSCI.0058-15.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Neurons coexpressing neuropeptide Y, agouti-related peptide, and GABA (NAG) play an important role in ingestive behavior and are located in the arcuate nucleus of the hypothalamus. NAG neurons receive both GABAergic and glutamatergic synaptic inputs, however, the developmental time course of synaptic input organization of NAG neurons in mice is unknown. In this study, we show that these neurons have low numbers of GABAergic synapses and that GABA is inhibitory to NAG neurons during early postnatal period. In contrast, glutamatergic inputs onto NAG neurons are relatively abundant by P13 and are comparatively similar to the levels observed in the adult. As mice reach adulthood (9-10 weeks), GABAergic tone onto NAG neurons increases. At this age, NAG neurons received similar numbers of inhibitory and EPSCs. To further differentiate age-associated changes in synaptic distribution, 17- to 18-week-old lean and diet-induced obesity (DIO) mice were studied. Surprisingly, NAG neurons from lean adult mice exhibit a reduction in the GABAergic synapses compared with younger adults. Conversely, DIO mice display reductions in the number of GABAergic and glutamatergic inputs onto NAG neurons. Based on these experiments, we propose that synaptic distribution in NAG neurons is continuously restructuring throughout development to accommodate the animals' energy requirements.
Collapse
|
13
|
Kobayashi R, He J, Lansky P. Estimation of the synaptic input firing rates and characterization of the stimulation effects in an auditory neuron. Front Comput Neurosci 2015; 9:59. [PMID: 26042025 PMCID: PMC4435043 DOI: 10.3389/fncom.2015.00059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/30/2015] [Indexed: 11/15/2022] Open
Abstract
To understand information processing in neuronal circuits, it is important to infer how a sensory stimulus impacts on the synaptic input to a neuron. An increase in neuronal firing during the stimulation results from pure excitation or from a combination of excitation and inhibition. Here, we develop a method for estimating the rates of the excitatory and inhibitory synaptic inputs from a membrane voltage trace of a neuron. The method is based on a modified Ornstein-Uhlenbeck neuronal model, which aims to describe the stimulation effects on the synaptic input. The method is tested using a single-compartment neuron model with a realistic description of synaptic inputs, and it is applied to an intracellular voltage trace recorded from an auditory neuron in vivo. We find that the excitatory and inhibitory inputs increase during stimulation, suggesting that the acoustic stimuli are encoded by a combination of excitation and inhibition.
Collapse
Affiliation(s)
- Ryota Kobayashi
- Principles of Informatics Research Division, National Institute of InformaticsTokyo, Japan
- Department of Informatics, SOKENDAI (The Graduate University for Advanced Studies)Tokyo, Japan
| | - Jufang He
- Department of Biomedical Sciences, City University of Hong KongHong Kong, China
| | - Petr Lansky
- Institute of Physiology, The Czech Academy of SciencesPrague, Czech Republic
| |
Collapse
|
14
|
Reig R, Zerlaut Y, Vergara R, Destexhe A, Sanchez-Vives MV. Gain modulation of synaptic inputs by network state in auditory cortex in vivo. J Neurosci 2015; 35:2689-702. [PMID: 25673859 DOI: 10.1523/JNEUROSCI.2004-14.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The cortical network recurrent circuitry generates spontaneous activity organized into Up (active) and Down (quiescent) states during slow-wave sleep or anesthesia. These different states of cortical activation gain modulate synaptic transmission. However, the reported modulation that Up states impose on synaptic inputs is disparate in the literature, including both increases and decreases of responsiveness. Here, we tested the hypothesis that such disparate observations may depend on the intensity of the stimulation. By means of intracellular recordings, we studied synaptic transmission during Up and Down states in rat auditory cortex in vivo. Synaptic potentials were evoked either by auditory or electrical (thalamocortical, intracortical) stimulation while randomly varying the intensity of the stimulus. Synaptic potentials evoked by the same stimulus intensity were compared in Up/Down states. Up states had a scaling effect on the stimulus-evoked synaptic responses: the amplitude of weaker responses was potentiated whereas that of larger responses was maintained or decreased with respect to the amplitude during Down states. We used a computational model to explore the potential mechanisms explaining this nontrivial stimulus-response relationship. During Up/Down states, there is different excitability in the network and the neuronal conductance varies. We demonstrate that the competition between presynaptic recruitment and the changing conductance might be the central mechanism explaining the experimentally observed stimulus-response relationships. We conclude that the effect that cortical network activation has on synaptic transmission is not constant but contingent on the strength of the stimulation, with a larger modulation for stimuli involving both thalamic and cortical networks.
Collapse
|
15
|
Wang XD, Chen C, Zhang D, Yao H. Cumulative latency advance underlies fast visual processing in desynchronized brain state. Proc Natl Acad Sci U S A 2014; 111:515-20. [PMID: 24347634 DOI: 10.1073/pnas.1316166111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals.
Collapse
|
16
|
Blackwell KT, Czubayko U, Plenz D. Quantitative estimate of synaptic inputs to striatal neurons during up and down states in vitro. J Neurosci 2003; 23:9123-32. [PMID: 14534246 PMCID: PMC6740825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
Up states are prolonged membrane potential depolarizations critical for synaptic integration and action potential generation in cortical and striatal neurons. They commonly result from numerous concurrent synaptic inputs, whereas neurons reside in a down state when synaptic inputs are few. By quantifying the composition, frequency, and amplitude of synaptic inputs for both states, we provide important constraints for state transitions in striatal network dynamics. Up and down states occur naturally in cortex-striatum-substantia nigra cocultures, which were used as an in vitro model in the present study. Spontaneous synaptic inputs during down states were extracted automatically in spiny projection neurons and fast spiking interneurons of the striatum using a newly developed computer algorithm. Consistent with a heterogeneous population of synaptic inputs, PSPs and PSCs showed no correlation in amplitude and rise time and occurred at relatively low frequencies of 10-40 Hz during the down state. The number of synaptic inputs during up states, estimated from the up-state charge and the unitary charge of down-state PSCs, was 217 +/- 44. Given the average up-state duration of 284 +/- 34 msec, synaptic input frequency was approximately 800 Hz during up-states for both neuronal types. Many down-state events reversed at the chloride reversal potential and were blocked by GABA(A) antagonists. The high correlation between up- and down-state reversal potential suggests that despite these drastic changes in synaptic input frequency, the ratio of inhibitory to excitatory currents is similar during both states.
Collapse
Affiliation(s)
- Kim T Blackwell
- Krasnow Institute of Advanced Studies and School of Computational Sciences, George Mason University, Fairfax, Virginia 22030, USA.
| | | | | |
Collapse
|
17
|
Wessel R, Kristan WB, Kleinfeld D. Supralinear summation of synaptic inputs by an invertebrate neuron: dendritic gain is mediated by an "inward rectifier" K(+) current. J Neurosci 1999; 19:5875-88. [PMID: 10407027 PMCID: PMC6783099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/1999] [Revised: 04/15/1999] [Accepted: 05/04/1999] [Indexed: 02/13/2023] Open
Abstract
Dendritic processing of glutamatergic synaptic inputs was investigated in the anterior pagoda cell of leech. We observed that below spike threshold, the amplitude of individual EPSPs decreased with hyperpolarization and that simultaneous stimulation of pairs of synaptic inputs leads to the supralinear summation of EPSPs. Voltage-clamp measurements revealed a hyperpolarization-activated, Ba(2+)-sensitive, fast, noninactivating K(+) conductance that depends on the external [K(+)]. These features are those of an "inward rectifier," Kir. Microsurgery experiments, in combination with electrophysiological measurements, revealed an inhomogeneous spatial distribution of the Kir conductance. Furthermore, on surgical removal of the neurites that contain the Kir conductance, the amplitude of EPSPs from the remaining synaptic inputs increased with hyperpolarization. A model cell, with the Kir conductance as the sole voltage-dependent conductance, reproduced qualitatively the observed voltage dependence of individual EPSPs as well as the supralinear summation of EPSP pairs.
Collapse
Affiliation(s)
- R Wessel
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | | | | |
Collapse
|