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Yin L, Han F, Yu Y, Wang Q. A computational network dynamical modeling for abnormal oscillation and deep brain stimulation control of obsessive-compulsive disorder. Cogn Neurodyn 2023; 17:1167-1184. [PMID: 37786657 PMCID: PMC10542091 DOI: 10.1007/s11571-022-09858-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 11/27/2022] Open
Abstract
Obsessive-compulsive disorder (OCD) is associated with multi-nodal abnormalities in brain networks, characterized by recurrent intrusive thoughts (obsessions) and repetitive behaviours or mental acts (compulsions), which might manifest as pathological low-frequency oscillations in the frontal EEG and low-frequency bursting firing patterns in the subthalamus nucleus (STN). Abnormalities in the cortical-striatal-thalamic-cortical (CSTC) loop, including dysregulation of serotonin, dopamine, and glutamate systems, are considered to contribute to certain types of OCD. Here, we extend a biophysical computational model to investigate the effect of orbitofronto-subcortical loop abnormalities on network oscillations. Particularly, the OCD lesion process is simulated by the loss of connectivity from striatal parvalbumin interneurons (PV) to medium spiny neurons (MSNs), excessive activation to the hyperdirect pathway, and high dopamine concentrations. By calculating low-frequency oscillation power in the STN, STN burst index, and average firing rates levels of the cortex and thalamus, we demonstrate that the model can explain the pathology of glutamatergic and dopamine system dysregulation, the effects of pathway imbalance, and neuropsychiatric treatment in OCD. In addition, results indicate the abnormal brain rhythms caused by the dysregulation of orbitofronto-subcortical loop may serve as a biomarker of OCD. Our studies can help to understand the cause of OCD, thereby facilitating the diagnosis of OCD and the development of new therapeutics.
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Affiliation(s)
- Lining Yin
- Department of Dynamics and Control, Beihang University, Beijing, 100191 China
| | - Fang Han
- College of Information Science and Technology, Donghua University, Shanghai, 201620 China
| | - Ying Yu
- School of Engineering Medicine, Beihang University, Beijing, 100191 China
| | - Qingyun Wang
- Department of Dynamics and Control, Beihang University, Beijing, 100191 China
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Ji YW, Xu XY, Yin C, Zhou C, Xiao C. Protocol to study projection-specific circuits in the basal ganglia of adult mice using viral vector tracing, optogenetics, and patch-clamp technique. STAR Protoc 2023; 4:102551. [PMID: 37660296 PMCID: PMC10491855 DOI: 10.1016/j.xpro.2023.102551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/24/2023] [Accepted: 08/10/2023] [Indexed: 09/05/2023] Open
Abstract
Analysis of synaptic strength and plasticity provides functional insights of complicated neural circuits. Here, we describe steps for cell- and projection-specific optogenetic manipulation of divergent basal ganglia circuits using anterograde and retrograde viral vectors. We quantitatively analyze synaptic function of these circuits utilizing a patch-clamp technique. This protocol is applicable to probe potential circuit targets for treatment of brain diseases. For complete details on the use and execution of this protocol, please refer to Ji et al.1.
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Affiliation(s)
- Ya-Wei Ji
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xiang-Ying Xu
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Cui Yin
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Chunyi Zhou
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China.
| | - Cheng Xiao
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China.
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3
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Xue T, Wang S, Chen S, Wang H, Liu C, Shi L, Bai Y, Zhang C, Han C, Zhang J. Subthalamic nucleus stimulation attenuates motor seizures via modulating the nigral orexin pathway. Front Neurosci 2023; 17:1157060. [PMID: 37214393 PMCID: PMC10196042 DOI: 10.3389/fnins.2023.1157060] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/17/2023] [Indexed: 05/24/2023] Open
Abstract
Background Focal motor seizures that originate in the motor region are a considerable challenge because of the high risk of permanent motor deficits after resection. Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a potential treatment for motor epilepsy that may enhance the antiepileptic actions of the substantia nigra pars reticulata (SNr). Orexin and its receptors have a relationship with both STN-DBS and epilepsy. We aimed to investigate whether and how STN inputs to the SNr regulate seizures and the role of the orexin pathway in this process. Methods A penicillin-induced motor epileptic model in adult male C57BL/6 J mice was established to evaluate the efficacy of STN-DBS in modulating seizure activities. Optogenetic and chemogenetic approaches were employed to regulate STN-SNr circuits. Selective orexin receptor type 1 and 2 antagonists were used to inhibit the orexin pathway. Results First, we found that high-frequency ipsilateral or bilateral STN-DBS was effective in reducing seizure activity in the penicillin-induced motor epilepsy model. Second, inhibition of STN excitatory neurons and STN-SNr projections alleviates seizure activities, whereas their activation amplifies seizure activities. In addition, activation of the STN-SNr circuits also reversed the protective effect of STN-DBS on motor epilepsy. Finally, we observed that STN-DBS reduced the elevated expression of orexin and its receptors in the SNr during seizures and that using a combination of selective orexin receptor antagonists also reduced seizure activity. Conclusion STN-DBS helps reduce motor seizure activity by inhibiting the STN-SNr circuit. Additionally, orexin receptor antagonists show potential in suppressing motor seizure activity and may be a promising therapeutic option in the future.
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Affiliation(s)
- Tao Xue
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shu Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shujun Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Huizhi Wang
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Chong Liu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Lin Shi
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yutong Bai
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chunkui Zhang
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Chunlei Han
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jianguo Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
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Ji YW, Zhang X, Fan JP, Gu WX, Shen ZL, Wu HC, Cui G, Zhou C, Xiao C. Differential remodeling of subthalamic projections to basal ganglia output nuclei and locomotor deficits in 6-OHDA-induced hemiparkinsonian mice. Cell Rep 2023; 42:112178. [PMID: 36857188 DOI: 10.1016/j.celrep.2023.112178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 11/04/2022] [Accepted: 02/13/2023] [Indexed: 03/02/2023] Open
Abstract
The subthalamic nucleus (STN) controls basal ganglia outputs via the substantia nigra pars reticulata (SNr) and the globus pallidus internus (GPi). However, the synaptic properties of these projections and their roles in motor control remain unclear. We show that the STN-SNr and STN-GPi projections differ markedly in magnitude and activity-dependent plasticity despite the existence of collateral STN neurons projecting to both the SNr and GPi. Stimulation of either STN projection reduces locomotion; in contrast, inhibition of either the STN-SNr projection or collateral STN neurons facilitates locomotion. In 6-OHDA-hemiparkinsonian mice, the STN-SNr projection is dramatically attenuated, but the STN-GPi projection is robustly enhanced; apomorphine inhibition of the STN-GPi projection through D2 receptors is significantly augmented and improves locomotion. Optogenetic inhibition of either the STN-SNr or STN-GPi projection improves parkinsonian bradykinesia. These results suggest that the STN-GPi and STN-SNr projections are differentially involved in motor control in physiological and parkinsonian conditions.
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Affiliation(s)
- Ya-Wei Ji
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xue Zhang
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou 221006, China
| | - Jiang-Peng Fan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Jiangsu Province Key Laboratory in Brain Diseases, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Wei-Xin Gu
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Department of Anesthesiology, Nanjing Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210008, China
| | - Zi-Lin Shen
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Hai-Chuan Wu
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Department of Anesthesiology, Nanjing Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210008, China
| | - Guiyun Cui
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou 221006, China.
| | - Chunyi Zhou
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China.
| | - Cheng Xiao
- School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China; Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China.
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Todd KL, Lipski J, Freestone PS. The Subthalamic Nucleus Exclusively Evokes Dopamine Release in the Tail of the Striatum. J Neurochem 2022; 162:417-429. [PMID: 35869680 PMCID: PMC9541146 DOI: 10.1111/jnc.15677] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/01/2022] [Accepted: 07/18/2022] [Indexed: 11/28/2022]
Abstract
A distinct population of dopamine neurons in the substantia nigra pars lateralis (SNL) has a unique projection to the most caudolateral (tail) region of the striatum. Here, using two electrochemical techniques to measure basal dopamine and electrically evoked dopamine release in anesthetized rats, we characterized this pathway, and compared it with the ‘classic’ nigrostriatal pathway from neighboring substantia nigra pars compacta (SNc) dopamine neurons to the dorsolateral striatum. We found that the tail striatum constitutes a distinct dopamine domain compared with the dorsolateral striatum, with consistently lower basal and evoked dopamine, and diverse dopamine release kinetics. Importantly, electrical stimulation of the SNL and SNc evoked dopamine release in entirely separate striatal regions; the tail and dorsolateral striatum, respectively. Furthermore, we showed that stimulation of the subthalamic nucleus (STN) evoked dopamine release exclusively in the tail striatum, likely via the SNL, consistent with previous anatomical evidence of STN afferents to SNL dopamine neurons. Our work identifies the STN as an important modulator of dopamine release in a novel dopamine pathway to the tail striatum, largely independent of the classic nigrostriatal pathway, which necessitates a revision of the basal ganglia circuitry with the STN positioned as a central integrator of striatal information.![]()
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Affiliation(s)
- Kathryn L. Todd
- Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand
| | - Janusz Lipski
- Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand
| | - Peter S. Freestone
- Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand
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6
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Bröer S. Not Part of the Temporal Lobe, but Still of Importance? Substantia Nigra and Subthalamic Nucleus in Epilepsy. Front Syst Neurosci 2020; 14:581826. [PMID: 33381016 PMCID: PMC7768985 DOI: 10.3389/fnsys.2020.581826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/09/2020] [Indexed: 01/15/2023] Open
Abstract
The most researched brain region in epilepsy research is the temporal lobe, and more specifically, the hippocampus. However, numerous other brain regions play a pivotal role in seizure circuitry and secondary generalization of epileptic activity: The substantia nigra pars reticulata (SNr) and its direct input structure, the subthalamic nucleus (STN), are considered seizure gating nuclei. There is ample evidence that direct inhibition of the SNr is capable of suppressing various seizure types in experimental models. Similarly, inhibition via its monosynaptic glutamatergic input, the STN, can decrease seizure susceptibility as well. This review will focus on therapeutic interventions such as electrical stimulation and targeted drug delivery to SNr and STN in human patients and experimental animal models of epilepsy, highlighting the opportunities for overcoming pharmacoresistance in epilepsy by investigating these promising target structures.
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Affiliation(s)
- Sonja Bröer
- Faculty of Veterinary Medicine, Institute of Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
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Beta Frequency Oscillations in the Subthalamic Nucleus Are Not Sufficient for the Development of Symptoms of Parkinsonian Bradykinesia/Akinesia in Rats. eNeuro 2019; 6:ENEURO.0089-19.2019. [PMID: 31540998 PMCID: PMC6817717 DOI: 10.1523/eneuro.0089-19.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/30/2019] [Accepted: 09/11/2019] [Indexed: 11/21/2022] Open
Abstract
Substantial correlative evidence links the synchronized, oscillatory patterns of neural activity that emerge in Parkinson's disease (PD) in the beta (β) frequency range (13-30 Hz) with bradykinesia in PD. However, conflicting evidence exists, and whether these changes in neural activity are causal of motor symptoms in PD remains unclear. We tested the hypothesis that the synchronized β oscillations that emerge in PD are causal of symptoms of bradykinesia/akinesia. We designed patterns of stimulation that mimicked the temporal characteristics of single unit β bursting activity seen in PD animals and humans. We applied these β-patterned stimulation patterns along with continuous low-frequency and high-frequency controls to the subthalamic nucleus (STN) of intact and 6-OHDA-lesioned female Long-Evans and Sprague-Dawley rats. β-Patterned paradigms were superior to low-frequency controls at induction of β power in downstream substantia nigra reticulata (SNr) neurons and in ipsilateral motor cortex. However, we did not detect deleterious effects on motor performance across a wide battery of validated behavioral tasks. Our results suggest that β frequency oscillations (BFOs) may not be sufficient for the generation of bradykinesia/akinesia in PD.
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8
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Cellular and Synaptic Dysfunctions in Parkinson's Disease: Stepping out of the Striatum. Cells 2019; 8:cells8091005. [PMID: 31470672 PMCID: PMC6769933 DOI: 10.3390/cells8091005] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 12/30/2022] Open
Abstract
The basal ganglia (BG) are a collection of interconnected subcortical nuclei that participate in a great variety of functions, ranging from motor programming and execution to procedural learning, cognition, and emotions. This network is also the region primarily affected by the degeneration of midbrain dopaminergic neurons localized in the substantia nigra pars compacta (SNc). This degeneration causes cellular and synaptic dysfunctions in the BG network, which are responsible for the appearance of the motor symptoms of Parkinson’s disease. Dopamine (DA) modulation and the consequences of its loss on the striatal microcircuit have been extensively studied, and because of the discrete nature of DA innervation of other BG nuclei, its action outside the striatum has been considered negligible. However, there is a growing body of evidence supporting functional extrastriatal DA modulation of both cellular excitability and synaptic transmission. In this review, the functional relevance of DA modulation outside the striatum in both normal and pathological conditions will be discussed.
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9
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Briones-Lizardi LJ, Cortés H, Avalos-Fuentes JA, Paz-Bermúdez FJ, Aceves J, Erlij D, Florán B. Presynaptic control of [3H]-glutamate release by dopamine receptor subtypes in the rat substantia nigra. Central role of D1 and D3 receptors. Neuroscience 2019; 406:563-579. [DOI: 10.1016/j.neuroscience.2019.03.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/20/2019] [Accepted: 03/21/2019] [Indexed: 02/07/2023]
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10
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Antonazzo M, Gutierrez-Ceballos A, Bustinza I, Ugedo L, Morera-Herreras T. Cannabinoids differentially modulate cortical information transmission through the sensorimotor or medial prefrontal basal ganglia circuits. Br J Pharmacol 2019; 176:1156-1169. [PMID: 30735570 PMCID: PMC6451076 DOI: 10.1111/bph.14613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/10/2018] [Accepted: 01/02/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE In the sensorimotor (SM) and medial prefrontal (mPF) basal ganglia (BG) circuits, the cortical information is transferred to the substantia nigra pars reticulata (SNr) through the hyperdirect trans-subthalamic pathway and through the direct and indirect trans-striatal pathways. The cannabinoid CB1 receptor, which is highly expressed in both BG circuits, may participate in the regulation of motor and motivational behaviours. Here, we investigated the modulation of cortico-nigral information transmission through the BG circuits by cannabinoids. EXPERIMENTAL APPROACH We used single-unit recordings of SNr neurons along with simultaneous electrical stimulation of motor or mPF cortex in anaesthetized rats. KEY RESULTS Cortical stimulation elicited a triphasic response in the SNr neurons from both SM and mPF-BG circuits, which consisted of an early excitation (hyperdirect transmission pathway), an inhibition (direct transmission pathway), and a late excitation (indirect transmission pathway). In the SM circuit, after Δ9 -tetrahydrocannabinol or WIN 55,212-2 administration, the inhibition and the late excitation were decreased or completely lost, whereas the early excitation response remained unaltered. However, cannabinoid administration dramatically decreased all the responses in the mPF circuit. The CB1 receptor antagonist AM251 (2 mg·kg-1 , i.v.) did not modify the triphasic response, but blocked the effects induced by cannabinoid agonists. CONCLUSIONS AND IMPLICATIONS CB1 receptor activation modulates the SM information transmission through the trans-striatal pathways and profoundly decreases the cortico-BG transmission through the mPF circuit. These results may be relevant for elucidating the involvement of the cannabinoid system in motor performance and in decision making or goal-directed behaviour.
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Affiliation(s)
- Mario Antonazzo
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,Neurodegenerative Diseases Group, Biocruces Health Research Institute, Barakaldo, Spain
| | - Amaia Gutierrez-Ceballos
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,Neurodegenerative Diseases Group, Biocruces Health Research Institute, Barakaldo, Spain
| | - Irati Bustinza
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,Neurodegenerative Diseases Group, Biocruces Health Research Institute, Barakaldo, Spain
| | - Luisa Ugedo
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,Neurodegenerative Diseases Group, Biocruces Health Research Institute, Barakaldo, Spain
| | - Teresa Morera-Herreras
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain.,Neurodegenerative Diseases Group, Biocruces Health Research Institute, Barakaldo, Spain
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Connectivity and Dynamics Underlying Synaptic Control of the Subthalamic Nucleus. J Neurosci 2019; 39:2470-2481. [PMID: 30700533 DOI: 10.1523/jneurosci.1642-18.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/29/2018] [Accepted: 01/24/2019] [Indexed: 12/16/2022] Open
Abstract
Adaptive motor control critically depends on the interconnected nuclei of the basal ganglia in the CNS. A pivotal element of the basal ganglia is the subthalamic nucleus (STN), which serves as a therapeutic target for deep brain stimulation (DBS) in movement disorders, such as Parkinson's disease. The functional connectivity of the STN at the microcircuit level, however, still requires rigorous investigation. Here we combine multiple simultaneous whole-cell recordings with extracellular stimulation and post hoc neuroanatomical analysis to investigate intrinsic and afferent connectivity and synaptic properties of the STN in acute brain slices obtained from rats of both sexes. Our data reveal an absence of intrinsic connectivity and an afferent innervation with low divergence, suggesting that STN neurons operate as independent processing elements driven by upstream structures. Hence, synchrony in the STN, a hallmark of motor processing, exclusively depends on the interactions and dynamics of GABAergic and glutamatergic afferents. Importantly, these inputs are subject to differential short-term depression when stimulated at high, DBS-like frequencies, shifting the balance of excitation and inhibition toward inhibition. Thus, we present a mechanism for fast yet transient decoupling of the STN from synchronizing afferent control. Together, our study provides new insights into the microcircuit organization of the STN by identifying its neurons as parallel processing units and thus sets new constraints for future computational models of the basal ganglia. The observed differential short-term plasticity of afferent inputs further offers a basis to better understand and optimize DBS algorithms.SIGNIFICANCE STATEMENT The subthalamic nucleus (STN) is a pivotal element of the basal ganglia and serves as target for deep brain stimulation, but information on the functional connectivity of its neurons is limited. To investigate the STN microcircuitry, we combined multiple simultaneous patch-clamp recordings and neuroanatomical analysis. Our results provide new insights into the synaptic organization of the STN identifying its neurons as parallel processing units and thus set new constraints for future computational models of the basal ganglia. We further find that synaptic dynamics of afferent inputs result in a rapid yet transient decoupling of the STN when stimulated at high frequencies. These results offer a better understanding of deep brain stimulation mechanisms, promoting the development of optimized algorithms.
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12
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Cáceres-Chávez VA, Hernández-Martínez R, Pérez-Ortega J, Herrera-Valdez MA, Aceves JJ, Galarraga E, Bargas J. Acute dopamine receptor blockade in substantia nigra pars reticulata: a possible model for drug-induced Parkinsonism. J Neurophysiol 2018; 120:2922-2938. [PMID: 30256736 DOI: 10.1152/jn.00579.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Dopamine (DA) depletion modifies the firing pattern of neurons in the substantia nigra pars reticulata (SNr), shifting their mostly tonic firing toward irregularity and bursting, traits of pathological firing underlying rigidity and postural instability in Parkinson's disease (PD) patients and animal models of Parkinsonism (PS). Drug-induced Parkinsonism (DIP) represents 20-40% of clinical cases of PS, becoming a problem for differential diagnosis, and is still not well studied with physiological tools. It may co-occur with tardive dyskinesia. Here we use in vitro slice preparations including the SNr to observe drug-induced pathological firing by using drugs that most likely produce it, DA-receptor antagonists (SCH23390 plus sulpiride), to compare with firing patterns found in DA-depleted tissue. The hypothesis is that SNr firing would be similar under both conditions, a prerequisite to the proposal of a similar preparation to test other DIP-producing drugs. Firing was analyzed with three complementary metrics, showing similarities between DA depletion and acute DA-receptor blockade. Moreover, blockade of either nonselective cationic channels or Cav3 T-type calcium channels hyperpolarized the membrane and abolished bursting and irregular firing, silencing SNr neurons in both conditions. Therefore, currents generating firing in control conditions are in part responsible for pathological firing. Haloperidol, a DIP-producing drug, reproduced DA-receptor antagonist firing modifications. Since acute DA-receptor blockade induces SNr neuron firing similar to that found in the 6-hydroxydopamine model of PS, output basal ganglia neurons may play a role in generating DIP. Therefore, this study opens the way to test other DIP-producing drugs. NEW & NOTEWORTHY Dopamine (DA) depletion enhances substantia nigra pars reticulata (SNr) neuron bursting and irregular firing, hallmarks of Parkinsonism. Several drugs, including antipsychotics, antidepressants, and calcium channel antagonists, among others, produce drug-induced Parkinsonism. Here we show the first comparison between SNr neuron firing after DA depletion vs. firing found after acute blockade of DA receptors. It was found that firing in both conditions is similar, implying that pathological SNr neuron firing is also a physiological correlate of drug-induced Parkinsonism.
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Affiliation(s)
| | - Ricardo Hernández-Martínez
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
| | - Jesús Pérez-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México , Querétaro, México
| | - Marco Arieli Herrera-Valdez
- Departamento de Matemáticas, Facultad de Ciencias, Universidad Nacional Autónoma de México , México City, México
| | - Jose J Aceves
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, México
| | - Elvira Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
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Gouty-Colomer LA, Michel FJ, Baude A, Lopez-Pauchet C, Dufour A, Cossart R, Hammond C. Mouse subthalamic nucleus neurons with local axon collaterals. J Comp Neurol 2017; 526:275-284. [DOI: 10.1002/cne.24334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/08/2017] [Accepted: 09/10/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Laurie-Anne Gouty-Colomer
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - François J Michel
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Agnès Baude
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Catherine Lopez-Pauchet
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | | | - Rosa Cossart
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Constance Hammond
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
- B&A Therapeutics, INMED; Marseille France
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Untangling Basal Ganglia Network Dynamics and Function: Role of Dopamine Depletion and Inhibition Investigated in a Spiking Network Model. eNeuro 2017; 3:eN-NWR-0156-16. [PMID: 28101525 PMCID: PMC5228592 DOI: 10.1523/eneuro.0156-16.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 11/22/2016] [Accepted: 11/27/2016] [Indexed: 12/30/2022] Open
Abstract
The basal ganglia are a crucial brain system for behavioral selection, and their function is disturbed in Parkinson's disease (PD), where neurons exhibit inappropriate synchronization and oscillations. We present a spiking neural model of basal ganglia including plausible details on synaptic dynamics, connectivity patterns, neuron behavior, and dopamine effects. Recordings of neuronal activity in the subthalamic nucleus and Type A (TA; arkypallidal) and Type I (TI; prototypical) neurons in globus pallidus externa were used to validate the model. Simulation experiments predict that both local inhibition in striatum and the existence of an indirect pathway are important for basal ganglia to function properly over a large range of cortical drives. The dopamine depletion-induced increase of AMPA efficacy in corticostriatal synapses to medium spiny neurons (MSNs) with dopamine receptor D2 synapses (CTX-MSN D2) and the reduction of MSN lateral connectivity (MSN-MSN) were found to contribute significantly to the enhanced synchrony and oscillations seen in PD. Additionally, reversing the dopamine depletion-induced changes to CTX-MSN D1, CTX-MSN D2, TA-MSN, and MSN-MSN couplings could improve or restore basal ganglia action selection ability. In summary, we found multiple changes of parameters for synaptic efficacy and neural excitability that could improve action selection ability and at the same time reduce oscillations. Identification of such targets could potentially generate ideas for treatments of PD and increase our understanding of the relation between network dynamics and network function.
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Ebert M, Hauptmann C, Tass PA. Coordinated reset stimulation in a large-scale model of the STN-GPe circuit. Front Comput Neurosci 2014; 8:154. [PMID: 25505882 PMCID: PMC4245901 DOI: 10.3389/fncom.2014.00154] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 11/05/2014] [Indexed: 11/15/2022] Open
Abstract
Synchronization of populations of neurons is a hallmark of several brain diseases. Coordinated reset (CR) stimulation is a model-based stimulation technique which specifically counteracts abnormal synchrony by desynchronization. Electrical CR stimulation, e.g., for the treatment of Parkinson's disease (PD), is administered via depth electrodes. In order to get a deeper understanding of this technique, we extended the top-down approach of previous studies and constructed a large-scale computational model of the respective brain areas. Furthermore, we took into account the spatial anatomical properties of the simulated brain structures and incorporated a detailed numerical representation of 2 · 104 simulated neurons. We simulated the subthalamic nucleus (STN) and the globus pallidus externus (GPe). Connections within the STN were governed by spike-timing dependent plasticity (STDP). In this way, we modeled the physiological and pathological activity of the considered brain structures. In particular, we investigated how plasticity could be exploited and how the model could be shifted from strongly synchronized (pathological) activity to strongly desynchronized (healthy) activity of the neuronal populations via CR stimulation of the STN neurons. Furthermore, we investigated the impact of specific stimulation parameters especially the electrode position on the stimulation outcome. Our model provides a step forward toward a biophysically realistic model of the brain areas relevant to the emergence of pathological neuronal activity in PD. Furthermore, our model constitutes a test bench for the optimization of both stimulation parameters and novel electrode geometries for efficient CR stimulation.
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Affiliation(s)
- Martin Ebert
- Institute of Neuroscience and Medicine - Neuromodulation, Juelich Research Center GmbH Juelich, Germany ; Department of Physics, Institute of Nuclear Physics, University of Cologne Cologne, Germany
| | - Christian Hauptmann
- Institute of Neuroscience and Medicine - Neuromodulation, Juelich Research Center GmbH Juelich, Germany
| | - Peter A Tass
- Institute of Neuroscience and Medicine - Neuromodulation, Juelich Research Center GmbH Juelich, Germany ; Department of Neurosurgery, Stanford University Stanford, CA, USA ; Department of Neuromodulation, University of Cologne Cologne, Germany
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Lindahl M, Kamali Sarvestani I, Ekeberg Ö, Kotaleski JH. Signal enhancement in the output stage of the basal ganglia by synaptic short-term plasticity in the direct, indirect, and hyperdirect pathways. Front Comput Neurosci 2013; 7:76. [PMID: 23801960 PMCID: PMC3685803 DOI: 10.3389/fncom.2013.00076] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/18/2013] [Indexed: 11/13/2022] Open
Abstract
Many of the synapses in the basal ganglia display short-term plasticity. Still, computational models have not yet been used to investigate how this affects signaling. Here we use a model of the basal ganglia network, constrained by available data, to quantitatively investigate how synaptic short-term plasticity affects the substantia nigra reticulata (SNr), the basal ganglia output nucleus. We find that SNr becomes particularly responsive to the characteristic burst-like activity seen in both direct and indirect pathway striatal medium spiny neurons (MSN). As expected by the standard model, direct pathway MSNs are responsible for decreasing the activity in SNr. In particular, our simulations indicate that bursting in only a few percent of the direct pathway MSNs is sufficient for completely inhibiting SNr neuron activity. The standard model also suggests that SNr activity in the indirect pathway is controlled by MSNs disinhibiting the subthalamic nucleus (STN) via the globus pallidus externa (GPe). Our model rather indicates that SNr activity is controlled by the direct GPe-SNr projections. This is partly because GPe strongly inhibits SNr but also due to depressing STN-SNr synapses. Furthermore, depressing GPe-SNr synapses allow the system to become sensitive to irregularly firing GPe subpopulations, as seen in dopamine depleted conditions, even when the GPe mean firing rate does not change. Similar to the direct pathway, simulations indicate that only a few percent of bursting indirect pathway MSNs can significantly increase the activity in SNr. Finally, the model predicts depressing STN-SNr synapses, since such an assumption explains experiments showing that a brief transient activation of the hyperdirect pathway generates a tri-phasic response in SNr, while a sustained STN activation has minor effects. This can be explained if STN-SNr synapses are depressing such that their effects are counteracted by the (known) depressing GPe-SNr inputs.
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Affiliation(s)
- Mikael Lindahl
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Iman Kamali Sarvestani
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Örjan Ekeberg
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Jeanette Hellgren Kotaleski
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
- Department of Neuroscience, Karolinska InstituteStockholm, Sweden
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17
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Abstract
The GABAergic projection neurons in the substantia nigra pars reticulata (SNr) are key basal ganglia output neurons. The activity of these neurons is critically influenced by the glutamatergic projection from the subthalamic nucleus (STN). The SNr also receives an intense serotonin (5-HT) innervation, raising the possibility that 5-HT may regulate the STN→SNr glutamatergic transmission and the consequent STN-triggered spike firing in SNr neurons. Here we show that 5-HT reduced STN stimulation-evoked long-lasting polysynaptic complex EPSCs in SNr GABA neurons. This inhibitory 5-HT effect was mimicked by the 5-HT1B receptor agonist CP93129 and blocked by the 5-HT1B antagonist NAS-181. 5-HT1A receptor ligands were ineffective. Additionally, 5-HT and CP93129 reduced the frequency but not the amplitude of miniature EPSCs, suggesting a reduced vesicular release. 5-HT and CP93129 also decreased the amplitude but increased the paired pulse ratio of the monosynaptic EPSCs in SNr GABA neurons, indicating a presynaptic 5-HT1B receptor-mediated inhibition of glutamate release. Furthermore, 5-HT and CP93129 inhibited STN-triggered burst firing in SNr GABA neurons, and CP93129's inhibitory effect was strongest when puffed to STN→SNr axon terminals in SNr, indicating a primary role of the 5-HT1B receptors in these axon terminals. Finally, the 5-HT1B receptor antagonist NAS-181 increased the STN-triggered complex EPSCs and burst firing in SNr GABA neurons, demonstrating the effects of endogenous 5-HT. These results suggest that nigral 5-HT, via presynaptic 5-HT1B receptor activation, gates the excitatory STN→SNr projection, reduces burst firing in SNr GABA neurons, and thus may play a critical role in movement control.
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TRPM2 channels are required for NMDA-induced burst firing and contribute to H(2)O(2)-dependent modulation in substantia nigra pars reticulata GABAergic neurons. J Neurosci 2013; 33:1157-68. [PMID: 23325252 DOI: 10.1523/jneurosci.2832-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Substantia nigra pars reticulata (SNr) GABAergic neurons are projection neurons that convey output from the basal ganglia to target structures. These neurons exhibit spontaneous regular firing, but also exhibit burst firing in the presence of NMDA or when excitatory glutamatergic input to the SNr is activated. Notably, an increase in burst firing is also seen in Parkinson's disease. Therefore, elucidating conductances that mediate spontaneous activity and changes of firing pattern in these neurons is essential for understanding how the basal ganglia control movement. Using ex vivo slices of guinea pig midbrain, we show that SNr GABAergic neurons express transient receptor potential melastatin 2 (TRPM2) channels that underlie NMDA-induced burst firing. Furthermore, we show that spontaneous firing rate and burst activity are modulated by the reactive oxygen species H(2)O(2) acting via TRPM2 channels. Thus, our results indicate that activation of TRPM2 channels is necessary for burst firing in SNr GABAergic neurons and their responsiveness to modulatory H(2)O(2). These findings have implications not only for normal regulation, but also for Parkinson's disease, which involves excitotoxicity and oxidative stress.
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Subthalamic lesion or levodopa treatment rescues giant GABAergic currents of PINK1-deficient striatum. J Neurosci 2013; 32:18047-53. [PMID: 23238720 DOI: 10.1523/jneurosci.2474-12.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cellular electrophysiological signatures of Parkinson's disease described in the pharmacological 6-hydroxydopamine (6-OHDA) animal models of Parkinson's disease include spontaneous repetitive giant GABAergic currents in a subpopulation of striatal medium spiny neurons (MSNs), and spontaneous rhythmic bursts of spikes generated by subthalamic nucleus (STN) neurons. We investigated whether similar signatures are present in Pink1(-/-) mice, a genetic rodent model of the PARK6 variant of Parkinson's disease. Although 9- to 24-month-old Pink1(-/-) mice show reduced striatal dopamine content and release, and impaired spontaneous locomotion, the relevance of this model to Parkinson's disease has been questioned because mesencephalic dopaminergic neurons do not degenerate during the mouse lifespan. We show that 75% of the MSNs of 5- to 7-month-old Pink1(-/-) mice exhibit giant GABAergic currents, occurring either singly or in bursts (at 40 Hz), rather than the low-frequency (2 Hz), low-amplitude, tonic GABAergic drive common to wild-type MSNs of the same age. STN neurons from 5- to 7-month-old Pink1(-/-) mice spontaneously generated bursts of spikes instead of the control tonic drive. Chronic kainic acid lesion of the STN or chronic levodopa treatment reliably suppressed the giant GABAergic currents of MSNs after 1 month and replaced them with the control tonic activity. The similarity between the in vitro resting states of Pink1 MSNs and those of fully dopamine (DA)-depleted MSNs of 6-OHDA-treated mice, together with the beneficial effect of levodopa treatment, strongly suggest that dysfunction of mesencephalic dopaminergic neurons in Pink1(-/-) mice is more severe than expected. The beneficial effect of the STN lesion also suggests that pathological STN activity strongly influences striatal networks in Pink1(-/-) mice.
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Barat E, Boisseau S, Bouyssières C, Appaix F, Savasta M, Albrieux M. Subthalamic nucleus electrical stimulation modulates calcium activity of nigral astrocytes. PLoS One 2012; 7:e41793. [PMID: 22848608 PMCID: PMC3407058 DOI: 10.1371/journal.pone.0041793] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The substantia nigra pars reticulata (SNr) is a major output nucleus of the basal ganglia, delivering inhibitory efferents to the relay nuclei of the thalamus. Pathological hyperactivity of SNr neurons is known to be responsible for some motor disorders e.g. in Parkinson's disease. One way to restore this pathological activity is to electrically stimulate one of the SNr input, the excitatory subthalamic nucleus (STN), which has emerged as an effective treatment for parkinsonian patients. The neuronal network and signal processing of the basal ganglia are well known but, paradoxically, the role of astrocytes in the regulation of SNr activity has never been studied. PRINCIPAL FINDINGS In this work, we developed a rat brain slice model to study the influence of spontaneous and induced excitability of afferent nuclei on SNr astrocytes calcium activity. Astrocytes represent the main cellular population in the SNr and display spontaneous calcium activities in basal conditions. Half of this activity is autonomous (i.e. independent of synaptic activity) while the other half is dependent on spontaneous glutamate and GABA release, probably controlled by the pace-maker activity of the pallido-nigral and subthalamo-nigral loops. Modification of the activity of the loops by STN electrical stimulation disrupted this astrocytic calcium excitability through an increase of glutamate and GABA releases. Astrocytic AMPA, mGlu and GABA(A) receptors were involved in this effect. SIGNIFICANCE Astrocytes are now viewed as active components of neural networks but their role depends on the brain structure concerned. In the SNr, evoked activity prevails and autonomous calcium activity is lower than in the cortex or hippocampus. Our data therefore reflect a specific role of SNr astrocytes in sensing the STN-GPe-SNr loops activity and suggest that SNr astrocytes could potentially feedback on SNr neuronal activity. These findings have major implications given the position of SNr in the basal ganglia network.
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Affiliation(s)
- Elodie Barat
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
| | - Sylvie Boisseau
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
| | - Céline Bouyssières
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
| | - Florence Appaix
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
| | - Marc Savasta
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
- Centre Hospitalier Universitaire de Grenoble, BP217, Grenoble F-38043, France
| | - Mireille Albrieux
- Institut National de la Santé et de la Recherche Médicale, U 836, Grenoble Institut des Neurosciences, Equipe Dynamique et Physiopathologie des Ganglions de la Base, Grenoble F-38043, France
- Université Joseph Fourier, Grenoble F- 38042, France
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21
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Farries MA, Wilson CJ. Phase response curves of subthalamic neurons measured with synaptic input and current injection. J Neurophysiol 2012; 108:1822-37. [PMID: 22786957 DOI: 10.1152/jn.00053.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Infinitesimal phase response curves (iPRCs) provide a simple description of the response of repetitively firing neurons and may be used to predict responses to any pattern of synaptic input. Their simplicity makes them useful for understanding the dynamics of neurons when certain conditions are met. For example, the sizes of evoked phase shifts should scale linearly with stimulus strength, and the form of the iPRC should remain relatively constant as firing rate varies. We measured the PRCs of rat subthalamic neurons in brain slices using corticosubthalamic excitatory postsynaptic potentials (EPSPs; mediated by both AMPA- and NMDA-type receptors) and injected current pulses and used them to calculate the iPRC. These were relatively insensitive to both the size of the stimulus and the cell's firing rate, suggesting that the iPRC can predict the response of subthalamic nucleus cells to extrinsic inputs. However, the iPRC calculated using EPSPs differed from that obtained using current pulses. EPSPs (normalized for charge) were much more effective at altering the phase of subthalamic neurons than current pulses. The difference was not attributable to the extended time course of NMDA receptor-mediated currents, being unaffected by blockade of NMDA receptors. The iPRC provides a good description of subthalamic neurons' response to input, but iPRCs are best estimated using synaptic inputs rather than somatic current injection.
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Affiliation(s)
- Michael A Farries
- Department of Biology, University of Texas San Antonio, San Antonio, Texas 78249, USA.
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22
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Bosch C, Mailly P, Degos B, Deniau JM, Venance L. Preservation of the hyperdirect pathway of basal ganglia in a rodent brain slice. Neuroscience 2012; 215:31-41. [DOI: 10.1016/j.neuroscience.2012.04.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/28/2012] [Accepted: 04/09/2012] [Indexed: 11/26/2022]
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23
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Shen KZ, Johnson SW. Regulation of polysynaptic subthalamonigral transmission by D2, D3 and D4 dopamine receptors in rat brain slices. J Physiol 2012; 590:2273-84. [PMID: 22371474 DOI: 10.1113/jphysiol.2011.225672] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Dopamine depletion in experimental models of Parkinson's disease promotes burst firing of neurons in the subthalamic nucleus (STN) and substantia nigra zona reticulata (SNR). A synaptically generated form of burst firing has been shown to arise from complex excitatory postsynaptic currents (EPSCs) that are evoked in SNR neurons by STN stimulation. The present experiments were designed to characterize actions of dopamine on complex EPSCs in slices of rat brain. Using patch pipettes to record whole-cell currents under voltage clamp, dopamine (30 μm) caused a reversible 64% reduction in complex EPSC charge. This effect was partially mimicked by D(2), D(3) and D(4) receptor agonists, and the action of dopamine could be nearly completely blocked by the combined effects of the D(2/3) antagonist sulpiride and the D(4) antagonist L-745,870. Local application of dopamine to the STN caused a larger inhibition of the complex EPSC (55% reduction) than did dopamine application to the SNR (15% reduction). Simple, monophasic EPSCs, which were evoked in SNR neurons by stimulating the SNR close to the recording pipette, were inhibited to a smaller extent compared to complex EPSCs. Bursts of action potentials evoked in SNR neurons by STN stimulation were inhibited by dopamine to a greater extent than was spontaneous firing. These results show that dopamine D(2)-like receptors inhibit complex EPSCs and burst discharges in the SNR by acting within the STN to suppress transmission in the subthalamonigral pathway. Dopamine receptor-mediated inhibition of polysynaptic connections in the STN might be beneficial in the treatment of Parkinson's disease.
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Affiliation(s)
- Ke-Zhong Shen
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
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Gamma-aminobutyric acid(B) receptor activation suppresses stimulus-evoked burst firing in rat substantia nigra reticulata neurons. Neuroreport 2012; 23:40-4. [PMID: 22127013 DOI: 10.1097/wnr.0b013e32834e4899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous whole-cell patch-pipette studies showed that focal electrical stimulation of the subthalamic nucleus (STN) evokes a long-lasting complex excitatory postsynaptic currents (EPSC) and synaptically evoked bursts of action potentials in substantia nigra pars reticulata (SNR) neurons. Although synaptically evoked bursting may play a role in normal physiology, excessive burst firing correlates with symptoms of Parkinson's disease. We used patch-pipette recordings in rat brain slices to study the effects of baclofen on complex EPSCs and STN-induced burst firing in SNR neurons. Baclofen (1 µM) caused a reversible, 73% reduction in complex EPSCs, and this effect was blocked by the γ-aminobutyric acid(B) antagonist CGP35348 (100 µM). Using the loose-patch method to record extracellular potentials, a lower concentration of baclofen (100 nM) inhibited STN-evoked bursts, while leaving spontaneous firing of action potentials less affected. We suggest that strategies that selectively inhibit burst firing in the SNR might have therapeutic potential in the treatment of Parkinson's disease.
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Ledonne A, Mango D, Bernardi G, Berretta N, Mercuri NB. A continuous high frequency stimulation of the subthalamic nucleus determines a suppression of excitatory synaptic transmission in nigral dopaminergic neurons recorded in vitro. Exp Neurol 2012; 233:292-302. [DOI: 10.1016/j.expneurol.2011.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 10/10/2011] [Accepted: 10/20/2011] [Indexed: 10/15/2022]
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Zhou FM, Lee CR. Intrinsic and integrative properties of substantia nigra pars reticulata neurons. Neuroscience 2011; 198:69-94. [PMID: 21839148 PMCID: PMC3221915 DOI: 10.1016/j.neuroscience.2011.07.061] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/07/2011] [Accepted: 07/14/2011] [Indexed: 11/27/2022]
Abstract
The GABA projection neurons of the substantia nigra pars reticulata (SNr) are output neurons for the basal ganglia and thus critical for movement control. Their most striking neurophysiological feature is sustained, spontaneous high frequency spike firing. A fundamental question is: what are the key ion channels supporting the remarkable firing capability in these neurons? Recent studies indicate that these neurons express tonically active type 3 transient receptor potential (TRPC3) channels that conduct a Na-dependent inward current even at hyperpolarized membrane potentials. When the membrane potential reaches -60 mV, a voltage-gated persistent sodium current (I(NaP)) starts to activate, further depolarizing the membrane potential. At or slightly below -50 mV, the large transient voltage-activated sodium current (I(NaT)) starts to activate and eventually triggers the rapid rising phase of action potentials. SNr GABA neurons have a higher density of I(NaT), contributing to the faster rise and larger amplitude of action potentials, compared with the slow-spiking dopamine neurons. I(NaT) also recovers from inactivation more quickly in SNr GABA neurons than in nigral dopamine neurons. In SNr GABA neurons, the rising phase of the action potential triggers the activation of high-threshold, inactivation-resistant Kv3-like channels that can rapidly repolarize the membrane. These intrinsic ion channels provide SNr GABA neurons with the ability to fire spontaneous and sustained high frequency spikes. Additionally, robust GABA inputs from direct pathway medium spiny neurons in the striatum and GABA neurons in the globus pallidus may inhibit and silence SNr GABA neurons, whereas glutamate synaptic input from the subthalamic nucleus may induce burst firing in SNr GABA neurons. Thus, afferent GABA and glutamate synaptic inputs sculpt the tonic high frequency firing of SNr GABA neurons and the consequent inhibition of their targets into an integrated motor control signal that is further fine-tuned by neuromodulators including dopamine, serotonin, endocannabinoids, and H₂O₂.
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Affiliation(s)
- F-M Zhou
- Department of Pharmacology, University of Tennessee College of Medicine, Memphis, TN 38163, USA.
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27
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Ammari R, Bioulac B, Garcia L, Hammond C. The Subthalamic Nucleus becomes a Generator of Bursts in the Dopamine-Depleted State. Its High Frequency Stimulation Dramatically Weakens Transmission to the Globus Pallidus. Front Syst Neurosci 2011; 5:43. [PMID: 21716635 PMCID: PMC3115486 DOI: 10.3389/fnsys.2011.00043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 06/01/2011] [Indexed: 11/29/2022] Open
Abstract
Excessive burst firing in the dopamine-depleted basal ganglia correlates with severe motor symptoms of Parkinson's disease that are attenuated by high frequency electrical stimulation of the subthalamic nucleus (STN). Here we test the hypothesis that pathological bursts in dopamine-deprived basal ganglia are generated within the STN and transmitted to globus pallidus neurons. To answer this question we recorded excitatory synaptic currents and potentials from subthalamic and pallidal neurons in the basal ganglia slice (BGS) from dopamine-depleted mice while continuously blocking GABAA receptors. In control mice, a single electrical stimulus delivered to the internal capsule or the rostral pole of the STN evoked a short duration, small amplitude, monosynaptic EPSC in subthalamic neurons. In contrast, in the dopamine-depleted BGS, this monosynaptic EPSC was amplified and followed by a burst of polysynaptic EPSCs that eventually reverberated three to seven times, providing a long lasting response that gave rise to bursts of EPSCs and spikes in GP neurons. Repetitive (10–120 Hz) stimulation delivered to the STN in the dopamine-depleted BGS attenuated STN-evoked bursts of EPSCs in pallidal neurons after several minutes of stimulation but only high frequency (90–120 Hz) stimulation replaced them with small amplitude EPSCs at 20 Hz. We propose that the polysynaptic pathway within the STN amplifies subthalamic responses to incoming excitation in the dopamine-depleted basal ganglia, thereby transforming the STN into a burst generator and entraining pallidal neurons in pathogenic bursting activities. High frequency stimulation of the STN prevents the transmission of this pathological activity to globus pallidus and imposes a new glutamatergic synaptic noise on pallidal neurons.
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28
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Zheng F, Lammert K, Nixdorf-Bergweiler BE, Steigerwald F, Volkmann J, Alzheimer C. Axonal failure during high frequency stimulation of rat subthalamic nucleus. J Physiol 2011; 589:2781-93. [PMID: 21486784 DOI: 10.1113/jphysiol.2011.205807] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Deep brain stimulation (DBS) has been established as an effective surgical therapy for advanced Parkinson's disease (PD) and gains increasing acceptance for otherwise intractable neuropsychiatric diseases such as major depression or obsessive–compulsive disorders. In PD, DBS targets predominantly the subthalamic nucleus (STN) and relieves motor deficits only at high frequency (>100 Hz). In contrast to the well-documented clinical efficacy of DBS, its underlying principle remains enigmatic spawning a broad and, in part, contradictory spectrum of suggested synaptic and non-synaptic mechanisms within and outside STN. Here we focused on a crucial, but largely neglected issue in this controversy, namely the axonal propagation of DBS within and away from STN. In rat brain slices preserving STN projections to substantia nigra (SN) and entopeduncular nucleus (EP, the rodent equivalent of internal globus pallidus), STN-DBS disrupted synaptic excitation onto target neurons through an unexpected failure of axonal signalling. The rapid onset and, upon termination of DBS, recovery of this effect was highly reminiscent of the time course of DBS in the clinical setting. We propose that DBS-induced suppression of axonal projections from and to STN serves to shield basal ganglia circuitry from pathological activity arising in or amplified by this nucleus.
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Affiliation(s)
- Fang Zheng
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Universitätsstraße 17, 91054 Erlangen, Germany
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Lee CR, Witkovsky P, Rice ME. Regulation of Substantia Nigra Pars Reticulata GABAergic Neuron Activity by H₂O₂ via Flufenamic Acid-Sensitive Channels and K ATP Channels. Front Syst Neurosci 2011; 5:14. [PMID: 21503158 PMCID: PMC3074506 DOI: 10.3389/fnsys.2011.00014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2011] [Accepted: 03/05/2011] [Indexed: 11/13/2022] Open
Abstract
Substantia nigra pars reticulata (SNr) GABAergic neurons are key output neurons of the basal ganglia. Given the role of these neurons in motor control, it is important to understand factors that regulate their firing rate and pattern. One potential regulator is hydrogen peroxide (H₂O₂), a reactive oxygen species that is increasingly recognized as a neuromodulator. We used whole-cell current clamp recordings of SNr GABAergic neurons in guinea-pig midbrain slices to determine how H₂O₂ affects the activity of these neurons and to explore the classes of ion channels underlying those effects. Elevation of H₂O₂ levels caused an increase in the spontaneous firing rate of SNr GABAergic neurons, whether by application of exogenous H₂O₂ or amplification of endogenous H₂O₂ through inhibition of glutathione peroxidase with mercaptosuccinate. This effect was reversed by flufenamic acid (FFA), implicating transient receptor potential (TRP) channels. Conversely, depletion of endogenous H₂O₂ by catalase, a peroxidase enzyme, decreased spontaneous firing rate and firing precision of SNr neurons, demonstrating tonic control of firing rate by H₂O₂. Elevation of H₂O₂ in the presence of FFA revealed an inhibition of tonic firing that was prevented by blockade of ATP-sensitive K(+) (K(ATP)) channels with glibenclamide. In contrast to guinea-pig SNr neurons, the dominant effect of H₂O₂ elevation in mouse SNr GABAergic neurons was hyperpolarization, indicating a species difference in H₂O₂-dependent regulation. Thus, H₂O₂ is an endogenous modulator of SNr GABAergic neurons, acting primarily through presumed TRP channels in guinea-pig SNr, with additional modulation via K(ATP) channels to regulate SNr output.
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Affiliation(s)
- Christian R Lee
- Department of Neurosurgery, New York University School of Medicine New York, NY, USA
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Hauptmann C, Tass PA. Restoration of segregated, physiological neuronal connectivity by desynchronizing stimulation. J Neural Eng 2010; 7:056008. [DOI: 10.1088/1741-2560/7/5/056008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tsirogiannis GL, Tagaris GA, Sakas D, Nikita KS. A population level computational model of the basal ganglia that generates parkinsonian Local Field Potential activity. BIOLOGICAL CYBERNETICS 2010; 102:155-176. [PMID: 20041261 DOI: 10.1007/s00422-009-0360-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 12/14/2009] [Indexed: 05/28/2023]
Abstract
Recordings from the basal ganglia's subthalamic nucleus are acquired via microelectrodes immediately prior to the application of Deep Brain Stimulation (DBS) treatment for Parkinson's Disease (PD) to assist in the selection of the final point for the implantation of the DBS electrode. The acquired recordings reveal a persistent characteristic beta band peak in the power spectral density function of the Local Field Potential (LFP) signals. This peak is considered to lie at the core of the causality-effect relationships of the parkinsonian pathophysiology. Based on LFPs acquired from human subjects during DBS for PD, we constructed a computational model of the basal ganglia on the population level that generates LFPs to identify the critical pathophysiological alterations that lead to the expression of the beta band peak. To this end, we used experimental data reporting that the strengths of the synaptic connections are modified under dopamine depletion. The hypothesis that the altered dopaminergic modulation may affect both the amplitude and the time course of the postsynaptic potentials is validated by the model. The results suggest a pivotal role of both of these parameters to the pathophysiology of PD.
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Affiliation(s)
- George L Tsirogiannis
- Biomedical Simulations and Imaging Laboratory, School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
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Subthalamic nucleus evokes similar long lasting glutamatergic excitations in pallidal, entopeduncular and nigral neurons in the basal ganglia slice. Neuroscience 2010; 166:808-18. [PMID: 20074618 DOI: 10.1016/j.neuroscience.2010.01.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 01/06/2010] [Indexed: 11/20/2022]
Abstract
The subthalamic nucleus (STN) modulates the activity of globus pallidus (GP), entopeduncular nucleus (EP) and substantia nigra pars reticulata (SNr) neurons via its direct glutamatergic projections. To investigate the mechanism by which STN affects activity in these structures and whether STN induced activity is comparable among STN target neurons, we performed patch clamp recordings in a tilted, parasagittal, basal ganglia slice (BGS) that preserves these functional connections. We report that single, brief stimulation of the STN generates a brief monosynaptic AMPA-mediated excitatory postsynaptic current (EPSC) in GP, EP and SNr neurons. A higher intensity, supra-threshold activation evokes a compound EPSC consisting of an early monosynaptic component followed by a slow inward NMDA-mediated current with an overlying barrage of AMPA-mediated EPSCs. These late EPSCs were polysynaptic and gave rise to bursts of spikes that lasted several hundreds of milliseconds. They were eliminated by surgical removal of the STN from the BGS slice, indicating that the STN is required for their generation. Reconstruction of biocytin-filled STN neurons revealed that a third of STN neurons project intra-STN axon collaterals that may underlie polysynaptic activity. We propose that activation of the STN yields comparable long lasting excitations in its target neurons by means of a polysynaptic network.
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Modolo J, Beuter A. Linking brain dynamics, neural mechanisms, and deep brain stimulation in Parkinson's disease: An integrated perspective. Med Eng Phys 2009; 31:615-23. [DOI: 10.1016/j.medengphy.2009.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 12/01/2008] [Accepted: 01/25/2009] [Indexed: 10/21/2022]
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Hauptmann C, Tass PA. Cumulative and after-effects of short and weak coordinated reset stimulation: a modeling study. J Neural Eng 2009; 6:016004. [PMID: 19141875 DOI: 10.1088/1741-2560/6/1/016004] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We show that the dynamical multistability of a network of bursting subthalamic neurons, caused by synaptic plasticity has a strong impact on the stimulus-response properties when exposed to weak and short desynchronizing stimuli. Intriguingly, such stimuli can reliably shift the network from a stable state with pathological synchrony and connectivity to a stable desynchronized state with down-regulated connectivity. However, unlike in the case of stronger coordinated reset stimulation, after termination of weaker stimulation the network may undergo a transient rebound of synchrony. When the coordinated reset stimulation is even weaker and/or shorter, so that a single stimulation epoch is not effective, the network dynamics and connectivity can still be reshaped in a cumulative manner by repetitive stimulation delivery.
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Affiliation(s)
- C Hauptmann
- Institute of Neuroscience and Biophysics 3, Medicine and Virtual Institute of Neuromodulation, Research Center Jülich, Leo-Brandt-Str., D-52425 Jülich, Germany.
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Shen KZ, Johnson SW. Complex EPSCs evoked in substantia nigra reticulata neurons are disrupted by repetitive stimulation of the subthalamic nucleus. Synapse 2008; 62:237-42. [PMID: 18236470 DOI: 10.1002/syn.20488] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although substantia nigra reticulata (SNR) neurons fire bursts of action potentials during normal movement, excessive burst firing correlates with symptoms of Parkinson's disease. A major excitatory output from the subthalamic nucleus (STN) to the SNR is thought to provide the synaptic impetus for burst firing in SNR neurons. Using patch pipettes to record from SNR neurons in rat brain slices, we found that a single electrical stimulus delivered to the STN evokes a burst of action potentials. Under voltage-clamp conditions, STN stimulation evokes a complex EPSC that is comprised of an initial monosynaptic EPSC followed by a series of late EPSCs superimposed on a long-lasting inward current. Using varied stimulation frequencies, we found that the initial EPSC was significantly reduced or abolished after 2 s of 50-100 Hz STN stimulation. However, only 4 s of 1 Hz stimulation was required to abolish the late component of the complex EPSC. We suggest that differential effects of repetitive STN stimulation on early and late components of complex EPSCs may help explain the frequency-dependent effects of deep brain stimulation of the STN that is used in the treatment of Parkinson's disease.
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Affiliation(s)
- Ke-Zhong Shen
- Department of Neurology, Oregon Health & Science University, Portland, Oregon 97239, USA
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Lee CR, Tepper JM. A calcium-activated nonselective cation conductance underlies the plateau potential in rat substantia nigra GABAergic neurons. J Neurosci 2007; 27:6531-41. [PMID: 17567814 PMCID: PMC6672447 DOI: 10.1523/jneurosci.1678-07.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Plateau potentials can be elicited in nigral GABAergic neurons by injection of 500 ms depolarizing current pulses from hyperpolarized holding potentials in whole-cell recordings in vitro. In approximately one-third of these neurons, plateau potentials were observed under control conditions and could be elicited in the remaining neurons after blocking potassium conductances. Application of the L-type calcium channel agonist Bay K 8644 or activation of NMDA receptors enhanced plateau potentials observed under control conditions and caused a plateau to be elicited in neurons not exhibiting it previously. The plateau potential was abolished in calcium-free buffer, as well as by nickel or cadmium. The L-type calcium channel blockers nimodipine and nifedipine abolished the plateau potential observed under control conditions but did not affect plateaus unmasked by tetraethylammonium. Plateau potentials observed under control conditions as well as those observed in the presence of Bay K 8644, NMDA, or tetraethylammonium were abolished in low-sodium buffer and by the calcium-activated nonselective cation conductance blocker flufenamic acid. These data suggest that nigral plateau potentials are mediated by a calcium-activated nonselective cation conductance (I(CAN)) that is activated by calcium entry predominantly through L-type calcium channels. In many nigral neurons, I(CAN) is masked by tetraethylammonium-sensitive potassium conductances, but plateaus can be evoked after increasing calcium conductances. The I(CAN)-mediated plateau potential in nigral GABAergic neurons likely affects the way these neurons integrate input and may represent a mechanism contributing to the rhythmic firing of these neurons seen in pathological conditions such as Parkinson's disease.
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Affiliation(s)
- Christian R. Lee
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102
| | - James M. Tepper
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102
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Hammond C, Bergman H, Brown P. Pathological synchronization in Parkinson's disease: networks, models and treatments. Trends Neurosci 2007; 30:357-64. [PMID: 17532060 DOI: 10.1016/j.tins.2007.05.004] [Citation(s) in RCA: 983] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 04/24/2007] [Accepted: 05/15/2007] [Indexed: 10/23/2022]
Abstract
Parkinson's disease is a common and disabling disorder of movement owing to dopaminergic denervation of the striatum. However, it is still unclear how this denervation perverts normal functioning to cause slowing of voluntary movements. Recent work using tissue slice preparations, animal models and in humans with Parkinson's disease has demonstrated abnormally synchronized oscillatory activity at multiple levels of the basal ganglia-cortical loop. This excessive synchronization correlates with motor deficit, and its suppression by dopaminergic therapies, ablative surgery or deep-brain stimulation might provide the basic mechanism whereby diverse therapeutic strategies ameliorate motor impairment in patients with Parkinson's disease. This review is part of the INMED/TINS special issue, Physiogenic and pathogenic oscillations: the beauty and the beast, based on presentations at the annual INMED/TINS symposium (http://inmednet.com/).
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Affiliation(s)
- Constance Hammond
- Institut de Neurobiologie de la Méditerranée, U29 Inserm, Université Aix-Marseille II and UMR CNRS 5543, Université Bordeaux 2, France
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