1
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Diamond JM, Lopes MB, Elias WJ, Jansen LA. Gamma-Aminobutyric Acid A Receptor Subunit Expression and Cellular Localization in the Human Parkinsonian Globus Pallidus. World Neurosurg 2022; 165:e159-e168. [PMID: 35659589 DOI: 10.1016/j.wneu.2022.05.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND The gamma-aminobutyric acid A (GABAA) receptor is an important mediator of cellular signaling in the globus pallidus and might be implicated in the pathophysiology of Parkinson disease (PD). The goal of the present study was to characterize GABAA receptor subunit expression in the normal and parkinsonian human globus pallidus. METHODS Postmortem brain specimens were obtained from 8 patients with pathological evidence of PD at autopsy and from 4 control patients without such evidence. These tissues were exposed to primary antibodies directed against the α1 and α3 subunits of the GABAA receptor and were visualized and quantified using fluorescence microscopy. RESULTS No differences were found in the pallidal neuronal density in the control versus PD tissues. Projection neurons strongly expressed the α1, α3, and β2 GABAA receptor subunits. After normalizing the immunofluorescence intensities in the globus pallidus to those in the adjacent structures, no significant differences were found in GABAA receptor subunit expression in the globus pallidus between the PD specimens and the control specimens. CONCLUSIONS Compensatory changes in GABAA receptor α1 and α3 subunit expression in response to PD-related signaling abnormalities in the globus pallidus did not occur in our PD cohort.
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Affiliation(s)
- Joshua M Diamond
- Department of Neurological Surgery, University of Virginia Medical Center, Charlottesville, Virginia, USA
| | - M Beatriz Lopes
- Department of Pathology, University of Virginia Medical Center, Charlottesville, Virginia, USA
| | - W Jeff Elias
- Department of Neurological Surgery, University of Virginia Medical Center, Charlottesville, Virginia, USA.
| | - Laura A Jansen
- Department of Neurology, University of Virginia Medical Center, Charlottesville, Virginia, USA
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2
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Hiscox LV, McGarry MDJ, Schwarb H, Van Houten EEW, Pohlig RT, Roberts N, Huesmann GR, Burzynska AZ, Sutton BP, Hillman CH, Kramer AF, Cohen NJ, Barbey AK, Paulsen KD, Johnson CL. Standard-space atlas of the viscoelastic properties of the human brain. Hum Brain Mapp 2020; 41:5282-5300. [PMID: 32931076 PMCID: PMC7670638 DOI: 10.1002/hbm.25192] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/28/2020] [Accepted: 08/16/2020] [Indexed: 12/16/2022] Open
Abstract
Standard anatomical atlases are common in neuroimaging because they facilitate data analyses and comparisons across subjects and studies. The purpose of this study was to develop a standardized human brain atlas based on the physical mechanical properties (i.e., tissue viscoelasticity) of brain tissue using magnetic resonance elastography (MRE). MRE is a phase contrast‐based MRI method that quantifies tissue viscoelasticity noninvasively and in vivo thus providing a macroscopic representation of the microstructural constituents of soft biological tissue. The development of standardized brain MRE atlases are therefore beneficial for comparing neural tissue integrity across populations. Data from a large number of healthy, young adults from multiple studies collected using common MRE acquisition and analysis protocols were assembled (N = 134; 78F/ 56 M; 18–35 years). Nonlinear image registration methods were applied to normalize viscoelastic property maps (shear stiffness, μ, and damping ratio, ξ) to the MNI152 standard structural template within the spatial coordinates of the ICBM‐152. We find that average MRE brain templates contain emerging and symmetrized anatomical detail. Leveraging the substantial amount of data assembled, we illustrate that subcortical gray matter structures, white matter tracts, and regions of the cerebral cortex exhibit differing mechanical characteristics. Moreover, we report sex differences in viscoelasticity for specific neuroanatomical structures, which has implications for understanding patterns of individual differences in health and disease. These atlases provide reference values for clinical investigations as well as novel biophysical signatures of neuroanatomy. The templates are made openly available (github.com/mechneurolab/mre134) to foster collaboration across research institutions and to support robust cross‐center comparisons.
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Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Elijah E W Van Houten
- Département de génie mécanique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Ryan T Pohlig
- College of Health Sciences, University of Delaware, Newark, Delaware, USA
| | - Neil Roberts
- School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
| | - Graham R Huesmann
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carle Neuroscience Institute, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Agnieszka Z Burzynska
- Department of Human Development and Family Studies and Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, Colorado, USA
| | - Bradley P Sutton
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Charles H Hillman
- Department of Psychology, Northeastern University, Boston, Massachusetts, USA.,Department of Physical Therapy, Movement, & Rehabilitation Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Arthur F Kramer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Aron K Barbey
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Keith D Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA
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3
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Huang Y, Yaple ZA, Yu R. Goal-oriented and habitual decisions: Neural signatures of model-based and model-free learning. Neuroimage 2020; 215:116834. [PMID: 32283275 DOI: 10.1016/j.neuroimage.2020.116834] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/03/2020] [Accepted: 04/08/2020] [Indexed: 11/26/2022] Open
Abstract
Human decision-making is mainly driven by two fundamental learning processes: a slow, deliberative, goal-directed model-based process that maps out the potential outcomes of all options and a rapid habitual model-free process that enables reflexive repetition of previously successful choices. Although many model-informed neuroimaging studies have examined the neural correlates of model-based and model-free learning, the concordant activity among these two processes remains unclear. We used quantitative meta-analyses of functional magnetic resonance imaging experiments to identify the concordant activity pertaining to model-based and model-free learning over a range of reward-related paradigms. We found that: 1) both processes yielded concordant ventral striatum activity, 2) model-based learning activated the medial prefrontal cortex and orbital frontal cortex, and 3) model-free learning specifically activated the left globus pallidus and right caudate head. Our findings suggest that model-free and model-based decision making engage overlapping yet distinct neural regions. These stereotaxic maps improve our understanding of how deliberative goal-directed and reflexive habitual learning are implemented in the brain.
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Affiliation(s)
- Yi Huang
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
| | - Zachary A Yaple
- Department of Psychology, National University of Singapore, Singapore
| | - Rongjun Yu
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore; Department of Psychology, National University of Singapore, Singapore.
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4
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Regulator of G protein signaling 14 (RGS14) is expressed pre- and postsynaptically in neurons of hippocampus, basal ganglia, and amygdala of monkey and human brain. Brain Struct Funct 2017; 223:233-253. [PMID: 28776200 DOI: 10.1007/s00429-017-1487-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/26/2017] [Indexed: 12/18/2022]
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional signaling protein primarily expressed in mouse pyramidal neurons of hippocampal area CA2 where it regulates synaptic plasticity important for learning and memory. However, very little is known about RGS14 protein expression in the primate brain. Here, we validate the specificity of a new polyclonal RGS14 antibody that recognizes not only full-length RGS14 protein in primate, but also lower molecular weight forms of RGS14 protein matching previously predicted human splice variants. These putative RGS14 variants along with full-length RGS14 are expressed in the primate striatum. By contrast, only full-length RGS14 is expressed in hippocampus, and shorter variants are completely absent in rodent brain. We report that RGS14 protein immunoreactivity is found both pre- and postsynaptically in multiple neuron populations throughout hippocampal area CA1 and CA2, caudate nucleus, putamen, globus pallidus, substantia nigra, and amygdala in adult rhesus monkeys. A similar cellular expression pattern of RGS14 in the monkey striatum and hippocampus was further confirmed in humans. Our electron microscopy data show for the first time that RGS14 immunostaining localizes within nuclei of striatal neurons in monkeys. Taken together, these findings suggest new pre- and postsynaptic regulatory functions of RGS14 and RGS14 variants, specific to the primate brain, and provide evidence for unconventional roles of RGS14 in the nuclei of striatal neurons potentially important for human neurophysiology and disease.
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Singh‐Bains MK, Waldvogel HJ, Faull RLM. The role of the human globus pallidus in Huntington's disease. Brain Pathol 2016; 26:741-751. [PMID: 27529459 PMCID: PMC8029019 DOI: 10.1111/bpa.12429] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/01/2016] [Indexed: 11/27/2022] Open
Abstract
Huntington's disease (HD) is characterized by pronounced pathology of the basal ganglia, with numerous studies documenting the pattern of striatal neurodegeneration in the human brain. However, a principle target of striatal outflow, the globus pallidus (GP), has received limited attention in comparison, despite being a core component of the basal ganglia. The external segment (GPe) is a major output of the dorsal striatum, connecting widely to other basal ganglia nuclei via the indirect motor pathway. The internal segment (GPi) is a final output station of both the direct and indirect motor pathways of the basal ganglia. The ventral pallidum (VP), in contrast, is a primary output of the limbic ventral striatum. Currently, there is a lack of consensus in the literature regarding the extent of GPe and GPi neurodegeneration in HD, with a conflict between pallidal neurons being preserved, and pallidal neurons being lost. In addition, no current evidence considers the fate of the VP in HD, despite it being a key structure involved in reward and motivation. Understanding the involvement of these structures in HD will help to determine their involvement in basal ganglia pathway dysfunction in the disease. A clear understanding of the impact of striatal projection loss on the main neurons that receive striatal input, the pallidal neurons, will aid in the understanding of disease pathogenesis. In addition, a clearer picture of pallidal involvement in HD may contribute to providing a morphological basis to the considerable variability in the types of motor, behavioral, and cognitive symptoms in HD. This review aims to highlight the importance of the globus pallidus, a critical component of the cortical-basal ganglia circuits, and its role in the pathogenesis of HD. This review also summarizes the current literature relating to human studies of the globus pallidus in HD.
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Affiliation(s)
- Malvindar K. Singh‐Bains
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
| | - Henry J. Waldvogel
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
| | - Richard L. M. Faull
- Centre for Brain Research, University of AucklandAucklandNew Zealand
- Department of Anatomy with Medical ImagingUniversity of AucklandAucklandNew Zealand
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6
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Vodicka P, Mo S, Tousley A, Green KM, Sapp E, Iuliano M, Sadri-Vakili G, Shaffer SA, Aronin N, DiFiglia M, Kegel-Gleason KB. Mass Spectrometry Analysis of Wild-Type and Knock-in Q140/Q140 Huntington's Disease Mouse Brains Reveals Changes in Glycerophospholipids Including Alterations in Phosphatidic Acid and Lyso-Phosphatidic Acid. J Huntingtons Dis 2016; 4:187-201. [PMID: 26397899 DOI: 10.3233/jhd-150149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a neurodegenerative disease caused by a CAG expansion in the HD gene, which encodes the protein Huntingtin. Huntingtin associates with membranes and can interact directly with glycerophospholipids in membranes. OBJECTIVE We analyzed glycerophospholipid profiles from brains of 11 month old wild-type (WT) and Q140/Q140 HD knock-in mice to assess potential changes in glycerophospholipid metabolism. METHODS Polar lipids from cerebellum, cortex, and striatum were extracted and analyzed by liquid chromatography and negative ion electrospray tandem mass spectrometry analysis (LC-MS/MS). Gene products involved in polar lipid metabolism were studied using western blotting, immuno-electron microscopy and qPCR. RESULTS Significant changes in numerous species of glycerophosphate (phosphatidic acid, PA) were found in striatum, cerebellum and cortex from Q140/Q140 HD mice compared to WT mice at 11 months. Changes in specific species could also be detected for other glycerophospholipids. Increases in species of lyso-PA (LPA) were measured in striatum of Q140/Q140 HD mice compared to WT. Protein levels for c-terminal binding protein 1 (CtBP1), a regulator of PA biosynthesis, were reduced in striatal synaptosomes from HD mice compared to wild-type at 6 and 12 months. Immunoreactivity for CtBP1 was detected on membranes of synaptic vesicles in striatal axon terminals in the globus pallidus. CONCLUSIONS These novel results identify a potential site of molecular pathology caused by mutant Huntingtin that may impart early changes in HD.
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Affiliation(s)
- Petr Vodicka
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Shunyan Mo
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Adelaide Tousley
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Karin M Green
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Maria Iuliano
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | | | - Scott A Shaffer
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Neil Aronin
- Departments of Medicine and Cell and Developmental Biology, UMASS Medical School, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
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7
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Hegeman DJ, Hong ES, Hernández VM, Chan CS. The external globus pallidus: progress and perspectives. Eur J Neurosci 2016; 43:1239-65. [PMID: 26841063 PMCID: PMC4874844 DOI: 10.1111/ejn.13196] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/20/2016] [Accepted: 01/27/2016] [Indexed: 12/12/2022]
Abstract
The external globus pallidus (GPe) of the basal ganglia is in a unique and powerful position to influence processing of motor information by virtue of its widespread projections to all basal ganglia nuclei. Despite the clinical importance of the GPe in common motor disorders such as Parkinson's disease, there is only limited information about its cellular composition and organizational principles. In this review, recent advances in the understanding of the diversity in the molecular profile, anatomy, physiology and corresponding behaviour during movement of GPe neurons are described. Importantly, this study attempts to build consensus and highlight commonalities of the cellular classification based on existing but contentious literature. Additionally, an analysis of the literature concerning the intricate reciprocal loops formed between the GPe and major synaptic partners, including both the striatum and the subthalamic nucleus, is provided. In conclusion, the GPe has emerged as a crucial node in the basal ganglia macrocircuit. While subtleties in the cellular makeup and synaptic connection of the GPe create new challenges, modern research tools have shown promise in untangling such complexity, and will provide better understanding of the roles of the GPe in encoding movements and their associated pathologies.
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Affiliation(s)
- Daniel J Hegeman
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Ellie S Hong
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Vivian M Hernández
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - C Savio Chan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
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8
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Eid L, Parent M. Chemical anatomy of pallidal afferents in primates. Brain Struct Funct 2016; 221:4291-4317. [PMID: 27028222 DOI: 10.1007/s00429-016-1216-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/15/2016] [Indexed: 12/24/2022]
Abstract
Neurons of the globus pallidus receive massive inputs from the striatum and the subthalamic nucleus, but their activity, as well as those of their striatal and subthalamic inputs, are modulated by brainstem afferents. These include serotonin (5-HT) projections from the dorsal raphe nucleus, cholinergic (ACh) inputs from the pedunculopontine tegmental nucleus, and dopamine (DA) afferents from the substantia nigra pars compacta. This review summarizes our recent findings on the distribution, quantitative and ultrastructural aspects of pallidal 5-HT, ACh and DA innervations. These results have led to the elaboration of a new model of the pallidal neuron based on a precise knowledge of the hierarchy and chemical features of the various synaptic inputs. The dense 5-HT, ACh and DA innervations disclosed in the associative and limbic pallidal territories suggest that these brainstem inputs contribute principally to the planification of motor behaviors and the regulation of attention and mood. Although 5-HT, ACh and DA inputs were found to modulate pallidal neurons and their afferents mainly through asynaptic (volume) transmission, genuine synaptic contacts occur between these chemospecific axon varicosities and pallidal dendrites, revealing that these brainstem projections have a direct access to pallidal neurons, in addition to their indirect input through the striatum and subthalamic nucleus. Altogether, these findings reveal that the brainstem 5-HT, ACh and DA pallidal afferents act in concert with the more robust GABAergic inhibitory striatopallidal and glutamatergic excitatory subthalamopallidal inputs. We hypothesize that a fragile equilibrium between forebrain and brainstem pallidal afferents plays a key role in the functional organization of the primate basal ganglia, in both health and disease.
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Affiliation(s)
- Lara Eid
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), Université Laval, F-6530-1, 2601, de la Canardière, Quebec, QC, G1J 2G3, Canada
| | - Martin Parent
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), Université Laval, F-6530-1, 2601, de la Canardière, Quebec, QC, G1J 2G3, Canada.
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9
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Gerfen C, Bolam J. The Neuroanatomical Organization of the Basal Ganglia. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-802206-1.00001-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Eid L, Parent M. Morphological evidence for dopamine interactions with pallidal neurons in primates. Front Neuroanat 2015; 9:111. [PMID: 26321923 PMCID: PMC4531254 DOI: 10.3389/fnana.2015.00111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/27/2015] [Indexed: 12/04/2022] Open
Abstract
The external (GPe) and internal (GPi) segments of the primate globus pallidus receive dopamine (DA) axonal projections arising mainly from the substantia nigra pars compacta and this innervation is here described based on tyrosine hydroxylase (TH) immunohistochemical observations gathered in the squirrel monkey (Saimiri sciureus). At the light microscopic level, unbiased stereological quantification of TH positive (+) axon varicosities reveals a similar density of innervation in the GPe (0.19 ± 0.02 × 106 axon varicosities/mm3 of tissue) and GPi (0.17 ± 0.01 × 106), but regional variations occur in the anteroposterior and dorsoventral axes in both GPe and GPi and along the mediolateral plane in the GPe. Estimation of the neuronal population in the GPe (3.47 ± 0.15 × 103 neurons/mm3) and GPi (2.69 ± 0.18 × 103) yields a mean ratio of, respectively, 28 ± 3 and 68 ± 15 TH+ axon varicosities/pallidal neuron. At the electron microscopic level, TH+ axon varicosities in the GPe appear significantly smaller than those in the GPi and very few TH+ axon varicosities are engaged in synaptic contacts in the GPe (17 ± 3%) and the GPi (15 ± 4%) compared to their unlabeled counterparts (77 ± 6 and 50 ± 12%, respectively). Genuine synaptic contacts made by TH+ axon varicosities in the GPe and GPi are of the symmetrical and asymmetrical type. Such synaptic contacts together with the presence of numerous synaptic vesicles in all TH+ axon varicosities observed in the GPe and GPi support the functionality of the DA pallidal innervation. By virtue of its predominantly volumic mode of action, DA appears to exert a key modulatory effect upon pallidal neurons in concert with the more direct GABAergic inhibitory and glutamatergic excitatory actions of the striatum and subthalamic nucleus. We argue that the DA pallidal innervation plays a major role in the functional organization of the primate basal ganglia under both normal and pathological conditions.
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Affiliation(s)
- Lara Eid
- Department of Psychiatry and Neuroscience, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval Quebec City, QC, Canada
| | - Martin Parent
- Department of Psychiatry and Neuroscience, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval Quebec City, QC, Canada
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11
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Coinciding decreases in discharge rate suggest that spontaneous pauses in firing of external pallidum neurons are network driven. J Neurosci 2015; 35:6744-51. [PMID: 25926452 DOI: 10.1523/jneurosci.5232-14.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The external segment of the globus pallidus (GPe) is one of the core nuclei of the basal ganglia, playing a major role in normal control of behavior and in the pathophysiology of basal ganglia-related disorders such as Parkinson's disease. In vivo, most neurons in the GPe are characterized by high firing rates (50-100 spikes/s), interspersed with long periods (∼0.6 s) of complete silence, which are termed GPe pauses. Previous physiological studies of single and pairs of GPe neurons have failed to fully disclose the physiological process by which these pauses originate. We examined 1001 simultaneously recorded pairs of high-frequency discharge GPe cells recorded from four monkeys during task-irrelevant periods, considering the activity in one cell while the other is pausing. We found that pauses (n = 137,278 pauses) coincide with a small yet significant reduction in firing rate (0.78 ± 0.136 spikes/s) in other GPe cells. Additionally, we found an increase in the probability of the simultaneously recorded cell to pause during the pause period of the "trigger" cell. Importantly, this increase in the probability to pause at the same time does not account for the reduction in firing rate by itself. Modeling of GPe cells as class 2 excitability neurons (Hodgkin, 1948) with common external inputs can explain our results. We suggest that common inputs decrease the GPe discharge rate and lead to a bifurcation phenomenon (pause) in some of the GPe neurons.
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12
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Baker-Nigh A, Vahedi S, Davis EG, Weintraub S, Bigio EH, Klein WL, Geula C. Neuronal amyloid-β accumulation within cholinergic basal forebrain in ageing and Alzheimer's disease. Brain 2015; 138:1722-37. [PMID: 25732182 DOI: 10.1093/brain/awv024] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/14/2014] [Indexed: 11/14/2022] Open
Abstract
The mechanisms that contribute to selective vulnerability of the magnocellular basal forebrain cholinergic neurons in neurodegenerative diseases, such as Alzheimer's disease, are not fully understood. Because age is the primary risk factor for Alzheimer's disease, mechanisms of interest must include age-related alterations in protein expression, cell type-specific markers and pathology. The present study explored the extent and characteristics of intraneuronal amyloid-β accumulation, particularly of the fibrillogenic 42-amino acid isoform, within basal forebrain cholinergic neurons in normal young, normal aged and Alzheimer's disease brains as a potential contributor to the selective vulnerability of these neurons using immunohistochemistry and western blot analysis. Amyloid-β1-42 immunoreactivity was observed in the entire cholinergic neuronal population regardless of age or Alzheimer's disease diagnosis. The magnitude of this accumulation as revealed by optical density measures was significantly greater than that in cortical pyramidal neurons, and magnocellular neurons in the globus pallidus did not demonstrate a similar extent of amyloid immunoreactivity. Immunoblot analysis with a panel of amyloid-β antibodies confirmed accumulation of high concentration of amyloid-β in basal forebrain early in adult life. There was no age- or Alzheimer-related alteration in total amyloid-β content within this region. In contrast, an increase in the large molecular weight soluble oligomer species was observed with a highly oligomer-specific antibody in aged and Alzheimer brains when compared with the young. Similarly, intermediate molecular weight oligomeric species displayed an increase in aged and Alzheimer brains when compared with the young using two amyloid-β42 antibodies. Compared to cortical homogenates, small molecular weight oligomeric species were lower and intermediate species were enriched in basal forebrain in ageing and Alzheimer's disease. Regional and age-related differences in accumulation were not the result of alterations in expression of the amyloid precursor protein, as confirmed by both immunostaining and western blot. Our results demonstrate that intraneuronal amyloid-β accumulation is a relatively selective trait of basal forebrain cholinergic neurons early in adult life, and increases in the prevalence of intermediate and large oligomeric assembly states are associated with both ageing and Alzheimer's disease. Selective intraneuronal amyloid-β accumulation in adult life and oligomerization during the ageing process are potential contributors to the degeneration of basal forebrain cholinergic neurons in Alzheimer's disease.
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Affiliation(s)
- Alaina Baker-Nigh
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Shahrooz Vahedi
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Elena Goetz Davis
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Sandra Weintraub
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Eileen H Bigio
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - William L Klein
- 2 Neurobiology, Northwestern University, Evanston, IL 60201, USA
| | - Changiz Geula
- 1 Cognitive Neurology and Alzheimer's Disease Centre, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
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13
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The local application of a flavonoid, (−)-epicatechin, increases the spiking of globus pallidus neurons in a dose-dependent manner and diminishes the catalepsy induced by haloperidol. Behav Pharmacol 2015; 26:117-24. [DOI: 10.1097/fbp.0000000000000100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Eid L, Parent A, Parent M. Asynaptic feature and heterogeneous distribution of the cholinergic innervation of the globus pallidus in primates. Brain Struct Funct 2014; 221:1139-55. [PMID: 25523104 PMCID: PMC4771818 DOI: 10.1007/s00429-014-0960-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/06/2014] [Indexed: 11/23/2022]
Abstract
The internal (GPi) and external (GPe) segments of the primate globus pallidus receive a significant cholinergic (ACh) innervation from the brainstem pedunculopontine tegmental nucleus. The present immunohistochemical study describes this innervation in the squirrel monkey (Saimiri sciureus), as visualized with an antibody raised against choline acetyltransferase (ChAT). At the light microscopic level, unbiased stereological quantification of ChAT positive (+) axon varicosities reveals a significantly lower density of innervation in GPi (0.26 ± 0.03 × 106) than in GPe (0.47 ± 0.07 × 106 varicosities/mm3 of tissue), with the anterior half of both segments more densely innervated than the posterior half. Neuronal density of GPi (3.00 ± 0.13 × 103 neurons/mm3) and GPe (3.62 ± 0.22 × 103 neurons/mm3) yields a mean ratio of ChAT+ axon varicosities per pallidal neuron of 74 ± 10 in the GPi and 128 ± 28 in the GPe. At the electron microscopic level, the pallidal ChAT+ axon varicosities are significantly smaller than their unlabeled counterparts, but are comparable in size and shape in the two pallidal segments. Only a minority of ChAT+ varicosities displays a synaptic specialization (12 % in the GPi and 17 % in the GPe); these scarce synaptic contacts are mostly of the symmetrical type and occur exclusively on pallidal dendrites. No ChAT+ axo-axonic synaptic contacts are observed, suggesting that ACh exerts its modulatory action on pallidal afferents through diffuse transmission, whereas pallidal neurons may be influenced by both volumic and synaptic delivery of ACh.
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Affiliation(s)
- Lara Eid
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), F-6530-1, 2601, ch. de la Canardière, Quebec, QC, G1J 2G3, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - André Parent
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), F-6530-1, 2601, ch. de la Canardière, Quebec, QC, G1J 2G3, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Quebec, QC, G1V 0A6, Canada
| | - Martin Parent
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), F-6530-1, 2601, ch. de la Canardière, Quebec, QC, G1J 2G3, Canada. .,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Quebec, QC, G1V 0A6, Canada.
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15
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Deffains M, Holland P, Moshel S, de Noriega FR, Bergman H, Israel Z. Higher neuronal discharge rate in the motor area of the subthalamic nucleus of Parkinsonian patients. J Neurophysiol 2014; 112:1409-20. [DOI: 10.1152/jn.00170.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In Parkinson's disease, pathological synchronous oscillations divide the subthalamic nucleus (STN) of patients into a dorsolateral oscillatory region and ventromedial nonoscillatory region. This bipartite division reflects the motor vs. the nonmotor (associative/limbic) subthalamic areas, respectively. However, significant topographic differences in the neuronal discharge rate between these two STN subregions in Parkinsonian patients is still controversial. In this study, 119 STN microelectrode trajectories (STN length > 2 mm, mean = 5.32 mm) with discernible oscillatory and nonoscillatory regions were carried on 60 patients undergoing deep brain stimulation surgery for Parkinson's disease. 2,137 and 2,152 multiunit stable signals were recorded (recording duration > 10 s, mean = 21.25 s) within the oscillatory and nonoscillatory STN regions, respectively. Spike detection and sorting were applied offline on every multiunit stable signal using an automatic method with systematic quantification of the isolation quality (range = 0–1) of the identified units. In all, 3,094 and 3,130 units were identified in the oscillatory and nonoscillatory regions, respectively. On average, the discharge rate of better-isolated neurons (isolation score > 0.70) was higher in the oscillatory region than the nonoscillatory region (44.55 ± 0.87 vs. 39.97 ± 0.77 spikes/s, N = 665 and 761, respectively). The discharge rate of the STN neurons was positively correlated to the strength of their own and their surrounding 13- to 30-Hz beta oscillatory activity. Therefore, in the Parkinsonian STN, beta oscillations and higher neuronal discharge rate are correlated and coexist in the motor area of the STN compared with its associative/limbic area.
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Affiliation(s)
- Marc Deffains
- Department of Medical Neurobiology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem, Israel
| | | | - Shay Moshel
- Department of Medical Neurobiology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem, Israel
- The Research Laboratory of Brain Imaging and Stimulation, The Jerusalem Mental Health Center, Kfar-Shaul Etanim, The Hebrew University-Hadassah Medical School, Jerusalem, Israel; and
| | - Fernando Ramirez de Noriega
- Center for Functional and Restorative Neurosurgery, Department of Neurosurgery, Hadassah University Hospital, Jerusalem, Israel
| | - Hagai Bergman
- Department of Medical Neurobiology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem, Israel
| | - Zvi Israel
- Center for Functional and Restorative Neurosurgery, Department of Neurosurgery, Hadassah University Hospital, Jerusalem, Israel
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González C, Mendoza J, Avila-Costa MR, Arias JM, Barral J. Golgi study of medium spiny neurons from dorsolateral striatum of the turtle Trachemys scripta elegans. Neurosci Lett 2013. [DOI: 10.1016/j.neulet.2013.10.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Eid L, Champigny MF, Parent A, Parent M. Quantitative and ultrastructural study of serotonin innervation of the globus pallidus in squirrel monkeys. Eur J Neurosci 2013; 37:1659-68. [PMID: 23432025 DOI: 10.1111/ejn.12164] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/16/2013] [Accepted: 01/21/2013] [Indexed: 11/29/2022]
Abstract
The present immunohistochemical study was aimed at characterizing the serotonin (5-HT) innervation of the internal (GPi) and external (GPe) pallidal segments in the squirrel monkey (Saimiri sciureus) with an antibody against the 5-HT transporter (SERT). At the light microscopic level, unbiased counts of SERT+ axon varicosities showed that the density of innervation is similar in the GPi (0.57 ± 0.03 × 10(6) varicosities/mm(3) of tissue) and the GPe (0.60 ± 0.04 × 10(6) ), with the anterior half of both segments being more densely innervated than the posterior half. Dorsoventral and mediolateral decreasing gradients of SERT varicosities occur in both pallidal segments, but are statistically significant only in the GPi. The neuronal density being significantly greater in the GPe (3.41 ± 0.23 × 10(3) neurons/mm(3) ) than in the GPi (2.90 ± 0.11 × 103), the number of 5-HT axon varicosities per pallidal neuron was found to be superior in the GPi (201 ± 27) than in the GPe (156 ± 26). At the electron microscopic level, SERT+ axon varicosities are comparable in size and vesicular content in GPi and GPe, where they establish mainly asynaptic contacts with unlabeled profiles. Less than 25% of SERT+ varicosities display a synaptic specialization, which is of the symmetrical or asymmetrical type and occurs exclusively on pallidal dendrites. No SERT+ axo-axonic synapses are present, suggesting that 5-HT exerts its well-established modulatory action upon various pallidal afferents mainly through diffuse transmission, whereas its direct control of pallidal neurons results from both volumic and synaptic release of the transmitter.
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Affiliation(s)
- Lara Eid
- Centre de Recherche de l'Institut Universitaire en santé Mentale de Québec, Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Quebec City, QC, Canada, G1J 2G3
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18
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Goldberg J, Bergman H. Computational physiology of the neural networks of the primate globus pallidus: function and dysfunction. Neuroscience 2011; 198:171-92. [DOI: 10.1016/j.neuroscience.2011.08.068] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 11/25/2022]
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Fishell G, Rudy B. Mechanisms of inhibition within the telencephalon: "where the wild things are". Annu Rev Neurosci 2011; 34:535-67. [PMID: 21469958 DOI: 10.1146/annurev-neuro-061010-113717] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this review, we first provide a historical perspective of inhibitory signaling from the discovery of inhibition through to our present understanding of the diversity and mechanisms by which GABAergic interneuron populations function in different parts of the telencephalon. This is followed by a summary of the mechanisms of inhibition in the CNS. With this as a starting point, we provide an overview describing the variations in the subtypes and origins of inhibitory interneurons within the pallial and subpallial divisions of the telencephalon, with a focus on the hippocampus, somatosensory, paleo/piriform cortex, striatum, and various amygdala nuclei. Strikingly, we observe that marked variations exist in the origin and numerical balance between GABAergic interneurons and the principal cell populations in distinct regions of the telencephalon. Finally we speculate regarding the attractiveness and challenges of establishing a unifying nomenclature to describe inhibitory neuron diversity throughout the telencephalon.
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Affiliation(s)
- Gord Fishell
- Smilow Neuroscience Program, Smilow Research Center, New York University School of Medicine, New York, New York 10016, USA.
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20
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Jaeger D, Kita H. Functional connectivity and integrative properties of globus pallidus neurons. Neuroscience 2011; 198:44-53. [PMID: 21835227 DOI: 10.1016/j.neuroscience.2011.07.050] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/21/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
Abstract
The globus pallidus consists of the external (GPe) and the internal (GPi) segments. The GPe and GPi have different functional roles. The GPe is located centrally within multiple basal ganglia feedforward and feedback connections. The GPi is an output nucleus of the basal ganglia. A complex interplay between intrinsic pacemaking conductances and the balance of glutamatergic and GABAergic input largely determines the rate and pattern of firing of pallidal neurons. The initial part of this article introduces recent findings made in vivo that are related to the roles of glutamatergic and GABAergic inputs in the control of pallidal activity. The latter part describes the roles of intrinsic mechanisms of GPe neurons in the integration of the synaptic inputs. The presence of dendritic voltage-gated sodium channels may allow the initiation of dendritic spikes, giving distal inputs on the long and thin GPe dendrites an opportunity to strongly shape spiking activity. Basal ganglia disorders including Parkinson's disease, hemiballismus, and dystonias are accompanied by increased irregularity and synchronized bursts of pallidal activity. These changes may be in part due to changes in the GABA release in the GPe and GPi, but also involve intrinsic cellular changes in pallidal neurons.
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Affiliation(s)
- D Jaeger
- Department of Biology, Emory University, Atlanta, GA 30322, USA.
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21
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Dendritic sodium channels regulate network integration in globus pallidus neurons: a modeling study. J Neurosci 2010; 30:15146-59. [PMID: 21068320 DOI: 10.1523/jneurosci.2662-10.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The globus pallidus (GP) predominantly contains GABAergic projection neurons that occupy a central position in the indirect pathway of the basal ganglia. They have long dendrites that can extend through one-half the diameter of the GP in rats, potentially enabling convergence and interaction between segregated basal ganglia circuits. Because of the length and fine diameter of GP dendrites, however, it is unclear how much influence distal synapses have on spiking activity. Dendritic expression of fast voltage-dependent Na(+) channels (NaF channels) can enhance the importance of distal excitatory synapses by allowing for dendritic spike initiation and by subthreshold boosting of EPSPs. Antibody labeling has demonstrated the presence of NaF channel proteins in GP dendrites, but the quantitative expression density of the channels remains unknown. We built a series of nine GP neuron models that differed only in their dendritic NaF channel expression level to assess the functional impact of this parameter. The models were all similar in their basic electrophysiological features; however, higher expression levels of dendritic NaF channels increased the relative effectiveness of distal inputs for both excitatory and inhibitory synapses, broadening the effective extent of the dendritic tree. Higher dendritic NaF channel expression also made the neurons more resistant to tonic inhibition and highly sensitive to clustered synchronous excitation. The dendritic NaF channel expression pattern may therefore be a critical determinant of convergence for both the striatopallidal and subthalamopallidal projections, while also dictating which spatiotemporal input patterns are most effective at driving GP neuron output.
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22
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Jacob AL, Jordan BA, Weinberg RJ. Organization of amyloid-beta protein precursor intracellular domain-associated protein-1 in the rat brain. J Comp Neurol 2010; 518:3221-36. [PMID: 20575057 PMCID: PMC2894292 DOI: 10.1002/cne.22394] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sustained activity-dependent synaptic modifications require protein synthesis. Although proteins can be synthesized locally in dendrites, long-term changes also require nuclear signaling. Amyloid-beta protein precursor intracellular domain-associated protein-1 (AIDA-1), an abundant component of the biochemical postsynaptic density fraction, contains a nuclear localization sequence, making it a plausible candidate for synapse-to-nucleus signaling. We used immunohistochemistry to study the regional, cellular, and subcellular distribution of AIDA-1. Immunostaining was prominent in the hippocampus, cerebral cortex, and neostriatum. Along with diffuse staining of neuropil, fluorescence microscopy revealed immunostaining of excitatory synapses throughout the forebrain, and immunoreactive puncta within and directly outside the nucleus. Presynaptic staining was conspicuous in hippocampal mossy fibers. Electron microscopic analysis of material processed for postembedding immunogold revealed AIDA-1 label within postsynaptic densities in both hippocampus and cortex. Together with previous work, these data suggest that AIDA-1 serves as a direct signaling link between synapses and the nucleus in adult rat brain.
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Affiliation(s)
- Amanda L Jacob
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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23
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Gerfen CR, Bolam JP. The Neuroanatomical Organization of the Basal Ganglia. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/b978-0-12-374767-9.00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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24
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Sims RE, Woodhall GL, Wilson CL, Stanford IM. Functional characterization of GABAergic pallidopallidal and striatopallidal synapses in the rat globus pallidus in vitro. Eur J Neurosci 2009; 28:2401-8. [PMID: 19087170 DOI: 10.1111/j.1460-9568.2008.06546.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
As a central integrator of basal ganglia function, the external segment of the globus pallidus (GP) plays a critical role in the control of voluntary movement. Driven by intrinsic mechanisms and excitatory glutamatergic inputs from the subthalamic nucleus, GP neurons receive GABAergic inhibitory input from the striatum (Str-GP) and from local collaterals of neighbouring pallidal neurons (GP-GP). Here we provide electrophysiological evidence for functional differences between these two inhibitory inputs. The basic synaptic characteristics of GP-GP and Str-GP GABAergic synapses were studied using whole-cell recordings with paired-pulse and train stimulation protocols and variance-mean (VM) analysis. We found (i) IPSC kinetics are consistent with local collaterals innervating the soma and proximal dendrites of GP neurons whereas striatal inputs innervate more distal regions. (ii) Compared to GP-GP synapses Str-GP synapses have a greater paired-pulse ratio, indicative of a lower probability of release. This was confirmed using VM analysis. (iii) In response to 20 and 50 Hz train stimulation, GP-GP synapses are weakly facilitatory in 1 mM external calcium and depressant in 2.4 mM calcium. This is in contrast to Str-GP synapses which display facilitation under both conditions. This is the first quantitative study comparing the properties of GP-GP and Str-GP synapses. The results are consistent with the differential location of these inhibitory synapses and subtle differences in their release probability which underpin stable GP-GP responses and robust short-term facilitation of Str-GP responses. These fundamental differences may provide the physiological basis for functional specialization.
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Affiliation(s)
- Robert E Sims
- Biomedical Sciences, School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
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25
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Elias S, Ritov Y, Bergman H. Balance of increases and decreases in firing rate of the spontaneous activity of basal ganglia high-frequency discharge neurons. J Neurophysiol 2008; 100:3086-104. [PMID: 18842958 DOI: 10.1152/jn.90714.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most neurons in the external and internal segments of the globus pallidus and the substantia nigra pars reticulata (GPe, GPi, and SNr) are characterized by a high-frequency discharge (HFD) rate (50-80 Hz) that, in most GPe neurons, is also interrupted by pauses. Almost all (approximately 90%) of the synaptic inputs to these HFD neurons are GABAergic and inhibitory. Nevertheless, their responses to behavioral events are usually dominated by increases in discharge rate. Additionally, there are no reports of prolonged bursts in the spontaneous activity of these cells that could reflect their disinhibition by GPe pauses. We recorded the spontaneous activity of 385 GPe, GPi, and SNr HFD neurons during a quiet-wakeful state from two monkeys. We developed three complementary methods to quantify the balance of increases and decreases in the spontaneous discharge of HFD neurons and validated them by simulations. Unlike the behavioral evoked responses, the spontaneous activity of pallidal and SNr neurons is not dominated by increases. Moreover, the activity of basal ganglia neurons does not include bursts that could reflect disinhibition by the spontaneous pauses of GPe neurons. These findings suggest that the discharge increase/decrease balance during a quiet-wakeful state better reflects the inhibitory input of the HFD basal ganglia neurons than during responses to behavioral events; however, the GPe pauses are not echoed by comparable bursts either in the GPe or in the output nuclei. Changes in the excitatory drive of these structures (e.g., during behavioral activity) thus may lead to a remarkable change in this balance.
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Affiliation(s)
- Shlomo Elias
- Department of Physiology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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Abstract
Studies of the basal ganglia and particularly the neostriatum have described a complex array of neuron types, synapses and putative transmitters. One approach to the study of such an area is to examine identified neurons and thus establish the neural circuits that underlie function. Striatal neurons have been identified under the light microscope by one or more of the following methods: (1) structure, based on Golgi impregnation or the intracellular injection of horseradish peroxidase (HRP); (2) projection area, by the retrograde transport of HRP or the tracing of HRP-injected or Golgi-impregnated axons; (3) chemistry, by immunocytochemistry, histochemistry or autoradiography, to reveal the presence of a selective uptake system for a putative transmitter. Examination of identified neurons in the electron microscope allows the characterization of their afferent synapses (by immunocytochemistry or anterograde degeneration) and their local synaptic output. The afferent and efferent synapses of five classes of identified striatal neurons are discussed: (1) those neurons described in Golgi preparations as medium-size and densely spiny; (2) a large type of striatonigral neuron; (3) GABAergic interneurons; (4) cholinergic neurons; (5) somatostatin-immunoreactive neurons. It is concluded that medium-size densely spiny neurons provide the basic framework of the neural circuits of the neostriatum.
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Abstract
The external segment of the pallidum (GP(e)) is a relatively large nucleus located caudomedial to the neostriatum (Str). The GP(e) receives major inputs from two major basal ganglia input nuclei, the Str and the subthalamic nucleus (STN), and sends its output to many basal ganglia nuclei including the STN, the Str, the internal pallidal segment (GP(i)), and the substantia nigra (SN). Thus, the GPe can be placed at the center of the basal ganglia connection diagram (Fig. 1(A)). From the viewpoint that emphasizes the direct and indirect pathways of the basal ganglia, the GP(e) is a component of the indirect pathway that relays Str inputs to the STN. The indirect pathway can be traced in Fig. 1(A), although it comprises only a part of multiple indirect pathways. This chapter begins with a brief description of the anatomical organization of the GP(e) followed by physiological and pharmacological characterizations of GABAergic responses in the GP(e).
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Affiliation(s)
- Hitoshi Kita
- Department of Anatomy and Neurobiology, The University of Tennessee Memphis, 855 Monroe Avenue, Memphis, TN 38163, USA.
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28
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Chan CS, Surmeier DJ, Yung WH. Striatal information signaling and integration in globus pallidus: timing matters. Neurosignals 2006; 14:281-9. [PMID: 16772731 DOI: 10.1159/000093043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 10/14/2005] [Indexed: 02/02/2023] Open
Abstract
Advances in research on globus pallidus (GP) suggest that this 'long thought to be' relay in the 'indirect pathway' plays a unique and critical role in basal ganglia function. The traditional idea of parallel processing within the basal ganglia is also challenged by recent findings. It is now clear that axons of GP neurons form large, perisomatic baskets around target neurons in all major basal ganglia nuclei, thereby exerting a profound influence on the output of the entire basal ganglia. GP neurons are autonomously active both in vivo and in vitro. It is believed that temporal information carried along the corticostriatopallidal pathway is critical for proper motor execution. The importance of appropriately controlled discharge of GP neurons is highlighted by psychomotor disorders such as Parkinson's disease, in which alterations in the pattern and synchrony of discharge in GP neurons are thought to contribute to motor symptoms. Several lines of evidence suggest that the aberrant activity of GP neurons following dopamine depletion is caused by alteration in the synaptic input from both striatum and subthalamic nucleus. In normal subjects, the capability of striatal input in translating cortical input into precisely timed responses in GP neurons is mediated by (1) the expression of postsynaptic GABA(A) receptor composed of subunits with fast kinetic properties; (2) an effective GABA reuptake system in terminating the action of synaptically released GABA, and (3) the existence of dendritic HCN channels that actively abbreviate the time course of the inhibitory postsynaptic potentials and reset rhythmic discharge. Despite the rapid pace in uncovering the elements that shape the activity along the striatopallidosubthalamic pathway, the origin of rhythmic, synchronized bursting of GP neurons seen in parkinsonism has not been fully established experimentally. Further elucidation of the factors that control the information transfer in the striatopallidal synapses is thus critical to our understanding of basal ganglia function and establishing treatment for Parkinson's disease and other basal ganglia disorders.
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Affiliation(s)
- C Savio Chan
- Department of Physiology and Institute for Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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29
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Yasukawa T, Kita T, Xue Y, Kita H. Rat intralaminar thalamic nuclei projections to the globus pallidus: A biotinylated dextran amine anterograde tracing study. J Comp Neurol 2004; 471:153-67. [PMID: 14986309 DOI: 10.1002/cne.20029] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The topographical organization and ultrastructural features of the intralaminar thalamic nuclei (ITN) projections to the globus pallidus (GP) were studied using the biotinylated dextran amine (BDA) anterograde tracing method in the rat. To assess the functional association of BDA injection sites in the ITN, the known topographical organization of the ITN-neostriatal (Str) projections and calcium binding protein (CaBP) immunostaining patterns of the Str and GP were used. BDA injection in the lateral part of the lateral parafascicular nucleus and the caudal part of the central lateral nucleus labeled fibers and boutons mainly in the dorsolateral sensorimotor territory of the Str and the middle territories of the GP. BDA injection in the medial part of the lateral parafascicular nucleus and the central lateral nucleus labeled mainly the middle association territory of the Str and the border and the caudomedial territories of the GP. BDA injection in the medial parafascicular nucleus and the central medial nucleus labeled mainly the medial limbic territory of the Str. The medial parafascicular nucleus projected to the medial-most region of the GP, while the central medial nucleus projection to the GP was very sparse. Electron microscopic observations indicated that BDA-labeled boutons form asymmetric synapses mainly on 0.5-2.0 microm diameter dendritic shafts in the GP. The boutons were small but had a relatively long active zone. The present observations together with the known topographical organization of striatopallidal projections indicated that the ITN-GP projections were topographically organized in parallel to the ITN-Str projections. Thus, each part of the ITN projecting to the sensorimotor, the association, and the limbic territories of the Str also projects to the corresponding functional territories of the GP.
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Affiliation(s)
- T Yasukawa
- Department of Anatomy and Neurobiology, College of Medicine, The University of Tennessee Memphis, Memphis, Tennessee 38163, USA
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30
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Bar-Gad I, Morris G, Bergman H. Information processing, dimensionality reduction and reinforcement learning in the basal ganglia. Prog Neurobiol 2003; 71:439-73. [PMID: 15013228 DOI: 10.1016/j.pneurobio.2003.12.001] [Citation(s) in RCA: 247] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2003] [Accepted: 12/01/2003] [Indexed: 11/17/2022]
Abstract
Modeling of the basal ganglia has played a major role in our understanding of this elusive group of nuclei. Models of the basal ganglia have undergone evolutionary and revolutionary changes over the last 20 years, as new research in the fields of anatomy, physiology and biochemistry of these nuclei has yielded new information. Early models dealt with a single pathway through the nuclei and focused on the nature of the processing performed within it, convergence of information versus parallel processing of information. Later, the Albin-DeLong "box-and-arrow" model characterized the inter-nuclei interaction as multiple pathways while maintaining a simplistic scalar representation of the nuclei themselves. This model made a breakthrough by providing key insights into the behavior of these nuclei in hypo- and hyper-kinetic movement disorders. The next generation of models elaborated the intra-nuclei interactions and focused on the role of the basal ganglia in action selection and sequence generation which form the most current consensus regarding basal ganglia function in both normal and pathological conditions. However, new findings challenge these models and point to a different neural network approach to information processing in the basal ganglia. Here, we take an in-depth look at the reinforcement driven dimensionality reduction (RDDR) model which postulates that the basal ganglia compress cortical information according to a reinforcement signal using optimal extraction methods. The model provides new insights and experimental predictions on the computational capacity of the basal ganglia and their role in health and disease.
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Affiliation(s)
- Izhar Bar-Gad
- Center for Neural Computation, The Hebrew University, Jerusalem, Israel.
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Abstract
Four organizational levels of the basal ganglia that could be particularly determinant in terms of functional properties are reviewed: (1) macroscopic anatomy, which is characterized by a dramatic decrease of cerebral tissue volume from the cerebral cortex to the deepest portions of the basal ganglia; (2) connectivity, which consists of both complex loops and a partition into three territories, sensorimotor, associative, and limbic (which process motor, cognitive, and emotional information, respectively); (3) neuronal morphology, characterized by a dramatic numeric and geometric convergence of striatal neurons onto pallidonigral neurons; and (4) dopaminergic innervation of the basal ganglia, which is organized as a dual system that is supposed to have opposite effects on the activity of the system. Current models of the basal ganglia are discussed.
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Affiliation(s)
- J Yelnik
- Institut National de la Santé et de la Recherche Médicale U289, Hôpital de la Salpêtrière, Paris, France.
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Cooper AJ, Stanford IM. Electrophysiological and morphological characteristics of three subtypes of rat globus pallidus neurone in vitro. J Physiol 2000; 527 Pt 2:291-304. [PMID: 10970430 PMCID: PMC2270075 DOI: 10.1111/j.1469-7793.2000.t01-1-00291.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2000] [Accepted: 06/19/2000] [Indexed: 11/26/2022] Open
Abstract
Neurones of the globus pallidus (GP) have been classified into three subgroups based on the visual inspection of current clamp electrophysiological properties and morphology of biocytin-filled neurones. Type A neurones (132/208; 63 %) were identified by the presence of the time- and voltage-dependent inward rectifier (Ih) and the low-threshold calcium current (It) giving rise to anodal break depolarisations. These cells were quiescent or fired regular spontaneous action potentials followed by biphasic AHPs. Current injection evoked regular activity up to maximum firing frequency of 350 Hz followed by moderate spike frequency adaptation. The somata of type A cells were variable in shape (20 x 12 micrometer) while their dendrites were highly varicose. Type B neurones (66/208; 32 %) exhibited neither Ih nor rebound depolarisations and only a fast monophasic AHP. These cells were spontaneously active while current injection induced irregular patterns of action potential firing up to a frequency of 440 Hz with weak spike frequency adaptation. Morphologically, these cells were the smallest encountered (15 x 10 micrometer), oval in shape with restricted varicose dendritic arborisations. Type C neurones were much rarer (10/208; 5 %). They were identified by the absence of Ih and rebound depolarisations, but did possess a prolonged biphasic AHP. They displayed large A-like potassium currents and ramp-like depolarisations in response to step current injections, which induced firing up to a maximum firing frequency of 310 Hz. These cells were the largest observed (27 x 15 micrometer) with extensive dendritic branching. These results confirm neuronal heterogeneity in the adult rodent GP. The driven activity and population percentage of the three subtypes correlates well with the in vivo studies (Kita & Kitai, 1991). Type A cells appear to correspond to type II neurones of Nambu & Llinas (1994, 1997) while the small diameter type B cells display morphological similarities with those described by Millhouse (1986). The rarely encountered type C cells may well be large cholinergic neurones. These findings provide a cellular basis for the study of intercellular communication and network interactions in the adult rat in vitro.
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Affiliation(s)
- A J Cooper
- Department of Pharmacology, Division of Neuroscience, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Sato F, Lavall�e P, L�vesque M, Parent A. Single-axon tracing study of neurons of the external segment of the globus pallidus in primate. J Comp Neurol 2000. [DOI: 10.1002/(sici)1096-9861(20000131)417:1<17::aid-cne2>3.0.co;2-i] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Broman J, Hassel B, Rinvik E, Ottersen O. Chapter 1 Biochemistry and anatomy of transmitter glutamate. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0924-8196(00)80042-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Waldvogel HJ, Kubota Y, Fritschy J, Mohler H, Faull RL. Regional and cellular localisation of GABA(A) receptor subunits in the human basal ganglia: An autoradiographic and immunohistochemical study. J Comp Neurol 1999; 415:313-40. [PMID: 10553118 DOI: 10.1002/(sici)1096-9861(19991220)415:3<313::aid-cne2>3.0.co;2-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The regional and cellular localisation of gamma-aminobutyric acid(A) (GABA(A)) receptors was investigated in the human basal ganglia using receptor autoradiography and immunohistochemical staining for five GABA(A) receptor subunits (alpha(1), alpha(2), alpha(3), beta(2, 3), and gamma(2)) and other neurochemical markers. The results demonstrated that GABA(A) receptors in the striatum showed considerable subunit heterogeneity in their regional distribution and cellular localisation. High densities of GABA(A) receptors in the striosome compartment contained the alpha(2), alpha(3), beta(2, 3), and gamma(2) subunits, and lower densities of receptors in the matrix compartment contained the alpha(1), alpha(2), alpha(3), beta(2,3), and gamma(2) subunits. Also, six different types of neurons were identified in the striatum on the basis of GABA(A) receptor subunit configuration, cellular and dendritic morphology, and chemical neuroanatomy. Three types of alpha(1) subunit immunoreactive neurons were identified: type 1, the most numerous (60%), were medium-sized aspiny neurons that were immunoreactive for parvalbumin and alpha(1), beta(2,3), and gamma(2) subunits; type 2 (38%) were medium-sized to large aspiny neurons immunoreactive for calretinin and alpha(1), alpha(3), beta(2,3), and gamma(2) subunits; and type 3 (2%) were large sparsely spiny neurons immunoreactive for alpha(1), alpha(3), beta(2,3), and gamma(2) subunits. Type 4 neurons were calbindin-positive and immunoreactive for alpha(2), alpha(3), beta(2,3), and gamma(2) subunits. The remaining neurons were immunoreactive for choline acetyltransferase (ChAT) and alpha(3) subunit (type 5) or were neuropeptide Y-positive with no GABA(A) receptor subunit immunoreactivity (type 6). The globus pallidus contained three types of neurons: types 1 and 2 were large neurons and were immunoreactive for alpha(1), alpha(3), beta(2,3), and gamma(2) subunits and for parvalbumin alone (type 1) or for both parvalbumin and calretinin (type 2); type 3 neurons were medium-sized and immunoreactive for calretinin and alpha(1), beta(2, 3), and gamma(2) subunits. These results show that the subunit composition of GABA(A) receptors displays considerable regional and cellular variation in the human striatum but are more homogeneous in the globus pallidus.
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Affiliation(s)
- H J Waldvogel
- Department of Anatomy with Radiology, Faculty of Medicine and Health Science, University of Auckland, Auckland, New Zealand.
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Kosinski CM, Risso Bradley S, Conn PJ, Levey AI, Landwehrmeyer GB, Penney JB, Young AB, Standaert DG. Localization of metabotropic glutamate receptor 7 mRNA and mGluR7a protein in the rat basal ganglia. J Comp Neurol 1999. [DOI: 10.1002/(sici)1096-9861(19991213)415:2<266::aid-cne9>3.0.co;2-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Hernández-Pineda R, Chow A, Amarillo Y, Moreno H, Saganich M, Vega-Saenz de Miera EC, Hernández-Cruz A, Rudy B. Kv3.1-Kv3.2 channels underlie a high-voltage-activating component of the delayed rectifier K+ current in projecting neurons from the globus pallidus. J Neurophysiol 1999; 82:1512-28. [PMID: 10482766 DOI: 10.1152/jn.1999.82.3.1512] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The globus pallidus plays central roles in the basal ganglia circuitry involved in movement control as well as in cognitive and emotional functions. There is therefore great interest in the anatomic and electrophysiological characterization of this nucleus. Most pallidal neurons are GABAergic projecting cells, a large fraction of which express the calcium binding protein parvalbumin (PV). Here we show that PV-containing pallidal neurons coexpress Kv3. 1 and Kv3.2 K+ channel proteins and that both Kv3.1 and Kv3.2 antibodies coprecipitate both channel proteins from pallidal membrane extracts solubilized with nondenaturing detergents, suggesting that the two channel subunits are forming heteromeric channels. Kv3.1 and Kv3.2 channels have several unusual electrophysiological properties when expressed in heterologous expression systems and are thought to play special roles in neuronal excitability including facilitating sustained high-frequency firing in fast-spiking neurons such as interneurons in the cortex and the hippocampus. Electrophysiological analysis of freshly dissociated pallidal neurons demonstrates that these cells have a current that is nearly identical to the currents expressed by Kv3.1 and Kv3.2 proteins in heterologous expression systems, including activation at very depolarized membrane potentials (more positive than -10 mV) and very fast deactivation rates. These results suggest that the electrophysiological properties of native channels containing Kv3.1 and Kv3.2 proteins in pallidal neurons are not significantly affected by factors such as associated subunits or postranslational modifications that result in channels having different properties in heterologous expression systems and native neurons. Most neurons in the globus pallidus have been reported to fire sustained trains of action potentials at high-frequency. Kv3.1-Kv3.2 voltage-gated K+ channels may play a role in helping maintain sustained high-frequency repetitive firing as they probably do in other neurons.
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Affiliation(s)
- R Hernández-Pineda
- Department of Physiology and Neuroscience and Department of Biochemistry, New York University School of Medicine, New York City, New York 10016, USA
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Plenz D, Herrera-Marschitz M, Kitai ST. Morphological organization of the globus pallidus-subthalamic nucleus system studied in organotypic cultures. J Comp Neurol 1998; 397:437-57. [PMID: 9699909 DOI: 10.1002/(sici)1096-9861(19980810)397:4<437::aid-cne1>3.0.co;2-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The morphological organization of the globus pallidus (GP), the subthalamic nucleus (STN), and the pallidosubthalamic projection was studied in organotypic cultures. Coronal slices from the GP, the STN, the striatum (CPu), and the cortex (Cx) were taken from the rat after postnatal days 0-2 and grown for 2 or 5-6 weeks. For analysis, immunocytochemistry against glutamate (GLU), parvalbumin (PV), and calretinin (CR) was combined with confocal microscopy. After 2 weeks in vitro, the STN showed a densely packed, homogeneous GLU-immunoreactive (ir) cell population. Pallidal GLU-ir neurons were heterogeneous, consisting of large-sized weakly GLU-ir neurons and small-sized intensively GLU-ir neurons. After 5-6 weeks in vitro, pallidal axons had radiated from numerous large-sized PV-ir cells and selectively innervated the STN, where they heavily ramified. Cultured STN neurons were not stained for PV; however, multipolar intensely PV-ir neurons were located at the border of the STN with their dendrites oriented towards the STN. Double labeling for PV and CR in both mature cultures and in the adult rat revealed that the culture CR-ir neurons from the GP, the Cpu, and from areas adjacent to the STN were different from cultured PV-ir neurons and their morphologies and distribution corresponded to that in vivo. These results demonstrate that 1) cultured CP and STN neurons display similar morphologies found in in vivo, 2) PV-ir pallidal neurons heavily and selectively innervate the STN; 3) there is a specific class of STN border neurons; and 4) in contrast to the in vivo situation, most cultured STN neurons are PV-negative.
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Affiliation(s)
- D Plenz
- University of Tennessee, College of Medicine, Department of Anatomy and Neurobiology, Memphis 38163, USA
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Waldvogel HJ, Fritschy JM, Mohler H, Faull RL. GABA(A) receptors in the primate basal ganglia: an autoradiographic and a light and electron microscopic immunohistochemical study of the alpha1 and beta2,3 subunits in the baboon brain. J Comp Neurol 1998; 397:297-325. [PMID: 9674559 DOI: 10.1002/(sici)1096-9861(19980803)397:3<297::aid-cne1>3.0.co;2-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The distribution of gamma-aminobutyric acid(A) (GABA(A)) receptors was investigated in the basal ganglia in the baboon brain by using receptor autoradiography and the immunohistochemical localisation of the alpha1 and beta2,3 subunits of the GABA(A) receptor by light and electron microscopy. In the caudate-putamen, the alpha1 subunit was distributed in high densities in the matrix compartment, and the beta2,3 subunits were more homogeneously distributed; the globus pallidus showed lower levels of the alpha1 and beta2,3 subunits. Four types of alpha1 subunit immunoreactive neurons were identified in the baboon striatum: the most numerous (75%) were type 1 medium-sized aspiny neurons; type 2 (2%) were large aspiny neurons with an indented nuclear membrane located in the ventral striatum; type 3 neurons were the least numerous (1%) and were comprised of large neurons in the ventromedial regions of the striatum; and type 4 (22%) neurons were medium to large aspiny neurons located in striosomes. At the ultrastructural level, alpha1 and beta2,3 subunit immunoreactivity was localised in the neuropil of the striatum in both symmetrical and asymmetrical synaptic contacts. In the globus pallidus, alpha1 and beta2,3 subunits were localised on large neurons and were found in three types of synaptic terminals: type 1 terminals were small and established symmetrical synapses; type 2 terminals were large; and type 3 terminals formed small synaptic terminals with subjunctional dense bodies. These results show that the subunit composition of GABA(A) receptors varies between the striosome and the matrix compartments in the striatum and that there is receptor subunit homogeneity in the globus pallidus.
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Affiliation(s)
- H J Waldvogel
- Department of Anatomy with Radiology, Faculty of Medicine and Health Science, University of Auckland, New Zealand.
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Kultas-Ilinsky K, Leontiev V, Whiting PJ. Expression of 10 GABA(A) receptor subunit messenger RNAs in the motor-related thalamic nuclei and basal ganglia of Macaca mulatta studied with in situ hybridization histochemistry. Neuroscience 1998; 85:179-204. [PMID: 9607711 DOI: 10.1016/s0306-4522(97)00634-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In situ hybridization histochemistry technique with [35S]UTP-labelled riboprobes was used to study the expression pattern of 10 GABA(A) receptor subunit messenger RNAs in the basal ganglia and motor thalamic nuclei of rhesus monkey. Human transcripts were used for the synthesis of alpha2, alpha4, beta2, beta3, gamma1 and delta subunit messenger RNA probes. Rat complementary DNAs were used for generating alpha1, alpha3, beta1 and gamma2 subunit messenger RNA probes. Nigral, pallidal and cerebellar afferent territories in the ventral tier thalamic nuclei all expressed alpha1, alpha2, alpha3, alpha4, beta1, beta2, beta3, delta and gamma2 subunit messenger RNAs but at different levels. Each intralaminar nucleus displayed its own unique expression pattern. In the thalamus, gamma1 subunit messenger RNA was detected only in the parafascicular nucleus. Comparison of the expression patterns with the known organization of GABA(A) connections in thalamic nuclei suggests that (i) the composition of the receptor associated with reticulothalamic synapses, except for those in the intralaminar nuclei, may be alpha1alpha4beta2delta, (ii) receptors of various other subunit compositions may operate in the local GABAergic circuits, and (iii) the composition of receptors at nigro- and pallidothalamic synapses may differ, with those at nigrothalamic probably containing beta1 and gamma2 subunits. In the medial and lateral parts of the globus pallidus, the subthalamic nucleus and the substantia nigra pars reticularis, the alpha1, beta2 and gamma2 messenger RNAs were co-expressed at a high level suggesting that this subunit composition was associated with all GABAergic synapses in the direct and indirect striatal output pathways. Various other subunit messenger RNAs were also expressed but at a lower level. In the substantia nigra pars compacta the most highly expressed messenger RNAs were alpha3, alpha4 and beta3; all other subunit messenger RNAs studied, except for gamma1, alpha1 and alpha2, were expressed at a moderate to high level. In the striatum, the following subunit messenger RNAs were expressed (listed in order of decreasing signal intensity): alpha4, beta3, alpha2, alpha3, beta2, delta, gamma2, alpha1. The expression patterns found in the monkey were similar to those described in comparable nuclei in the rat by Wisden et al. [J. Neurosci. (1992), 12, p. 1040]; however, the monkey nuclei displayed a much greater variety of GABA(A) receptor subunit messenger RNAs.
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Affiliation(s)
- K Kultas-Ilinsky
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City 52242, USA
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41
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Abstract
Cholinergic neurons in the basal forebrain are the focus of considerable interest because they are severely affected in Alzheimer's disease. However, both cholinergic and noncholinergic neurons are intermingled in this region. The goal of the present study was to characterize the morphology and in vivo electrophysiology of noncholinergic basal forebrain neurons. Neurons in the ventral pallidum and substantia innominata were recorded extracellularly, labeled juxtacellularly with biocytin and characterized for the presence of choline acetyltransferase immunoreactivity. Two types of ventral pallidal cells were observed. Type I ventral pallidal neurons had axons that rarely branched near the cell body and tended to have smaller somata and lower spontaneous firing rates than did type II ventral pallidal neurons, which displayed extensive local axonal arborizations. Subtypes of substantia innominata neurons could not be distinguished based on axonal morphology. These noncholineregic neurons exhibited local axon arborizations along a continuum that varied from no local collaterals to quite extensive arbors. Substantia innominata neurons had lower spontaneous firing rates, more variable interspike intervals, and different spontaneous firing patterns than did type II ventral pallidal neurons and could be antidromically activated from cortex or substantia nigra, indicating that they were projection neurons. Ventral pallidal neurons resemble, both morphologically and electrophysiologically, previously described neurons in the globus pallidus, whereas the substantia innominata neurons bore similarities to isodendritic neurons of the reticular formation. These results demonstrate the heterogeneous nature of noncholinergic neurons in the basal forebrain.
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Affiliation(s)
- K Pang
- Center for Molecular and Behavioral Neurosciences, Rutgers, The State University of New Jersey, Newark 07102, USA.
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Sobkowicz HM, Slapnick SM, Nitecka LM, August BK. Compound synapses within the GABAergic innervation of the auditory inner hair cells in the adolescent mouse. J Comp Neurol 1997; 377:423-42. [PMID: 8989656 DOI: 10.1002/(sici)1096-9861(19970120)377:3<423::aid-cne9>3.0.co;2-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ultrastructural investigation of the gamma-aminobutyric acid (GABA) component of the inner spiral bundle in adolescent mice revealed a pathway of glutamic acid decarboxylase (GAD)-positive and -negative fibers and vesiculated endings that contact inner hair cells and their afferents through a complex of axosomatic and axodendritic synapses. Ultrastructural details were investigated by using conventional electron microscopy. Several synaptic arrangements were observed: Main axosomatic synapses form between vesiculated endings and individual or adjoining inner hair cells (interreceptor synapses). Spinous synapses form on long, spinelike processes that protrude from inner hair cells to reach distant efferent endings. The efferent endings associate with inner hair cells and their synaptic afferents through compound synapses-serial, "converging," and triadic-otherwise characteristic of sensory relay nuclei. Serial synapses form by the sequential presynaptic alignment of the efferent-->receptor-->afferent components. Converging synapses result from the simultaneous apposition of a receptor ribbon synapse and a presynaptic efferent terminal on a recipient afferent dendrite. Triadic synapses comprise a vesiculated efferent ending in contact with an inner hair cell and with its synaptic afferent. Additionally, efferent endings may form simple axodendritic and axoaxonal synapses with GAD-negative vesiculated endings. The combination of different synaptic arrangements leads to short chains of compound synapses. It is assumed that these synaptic patterns seen in the adolescent mouse represent adult synaptology. The patterns of synaptic connectivity suggest an integrative role for the GABA/GAD lateral efferent system, and imply its involvement in the pre- and postsynaptic modulation of auditory signals.
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Affiliation(s)
- H M Sobkowicz
- Department of Neurology, University of Wisconsin, Madison 53706, USA.
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44
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Abstract
This paper describes the distribution of the calcium-binding proteins calbindin-D28k. Parvalbumin and calretinin in primate basal ganglia. The data derive from immunocytochemical studies undertaken in squirrel monkeys (Saimiri sciureus) and in normal human individuals. In the striatum, calbindin labels medium-sized spiny projection neurons whereas parvalbumin and calretinin mark two separate classes of aspiny interneurons. The striatal matrix compartment is markedly enriched with calbindin while striatal patches (striosomes) display a calretinin-rich neuropil. In the pallidum, virtually all neurons contain parvalbumin but none express calbindin. Calretinin occurs only in a small subpopulation of both large and small pallidal neurons. In the subthalamic nucleus, there exists a multitude of parvalbumun-positive cells and fibers but the number of calretinin and calbindin-positive neuronal elements is small. In the substantia nigra/ventral tegmental area complex, calbindin and calretinin occur principally in dopaminergic neurons of the dorsal tier of the pars compacta and in those of the ventral tegmental area. Parvalbumin is strictly confined to the GABAergic neurons of the pars reticulata and lateralis. Calbindin-rich fibers abound in the pars reticulata and lateralis, while calretinin-positive axons are confined to the pars compacta. These results indicate that calbindin and parvalbumin are distributed according to a strikingly complementary pattern in primate basal ganglia. Calretinin is less ubiquitous but occurs in all basal ganglia components where it labels distinct subsets of neurons. Such highly specific patterns of distribution indicate that calbindin, parvalbumin and calretinin may work in synergy within primate basal ganglia.
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Affiliation(s)
- A Parent
- Centre de recherche en Neurobiologie, Hôpital de I'Enfant-Jésus, Québec, Canada.
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Shink E, Smith Y. Differential synaptic innervation of neurons in the internal and external segments of the globus pallidus by the GABA- and glutamate-containing terminals in the squirrel monkey. J Comp Neurol 1995; 358:119-41. [PMID: 7560274 DOI: 10.1002/cne.903580108] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The present study aimed at comparing the pattern of synaptic innervation of neurons in the external (GPe) and internal (GPi) pallidum by gamma-aminobutyric acid (GABA)- and glutamate-immunoreactive terminals in the squirrel monkey. Four major populations of terminals were encountered in GPe and GPi. Our findings combined with those obtained in previous tract-tracing studies reveal that the synaptic innervation of perikarya in GPe is strikingly different from that in GPi. Although the GABA-positive type I boutons (from the striatum) represent 85% of the terminals in contact with somata in GPe, only 32% of the axosomatic synapses involve this type of terminal in GPi. However, the type II terminals (from GPe), which display a moderate level of GABA and glutamate immunoreactivities, account for 48% of the boutons in contact with perikarya in GPi but only 10% in GPe. In both pallidal segments, less than 10% of the axosomatic synapses involve the glutamate-immunoreactive type III terminals (from the subthalamic nucleus). Finally, the type IIa boutons (unknown source), which show levels of immunoreactivities similar to the type II terminals, account for 12% of the boutons in contact with perikarya in GPi but only 4% in GPe. In contrast to perikarya, the innervation of dendritic shafts is similar in both GPe and GPi; more than 80% of the axodendritic synapses involve the type I terminals, 10-15% involve the type III terminals, less than 5% are formed by the type II boutons, and less than 1% involve the type IIa terminals. Three other categories of boutons (types IV, V, VI) account for less than 1% of the total population of terminals in GPe and GPi. In conclusion, our findings demonstrate a differential synaptic innervation of neuronal perikarya in GPe and GPi in primates. These data suggest that the two pallidal segments are separate functional entities of which the neuronal activity is largely controlled by extrinsic inputs that are differentially distributed at the level of single cells.
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Affiliation(s)
- E Shink
- Centre de Recherche en Neurobiologie, Faculté de Médecine, Université Laval et Hôpital de l'Enfant-Jésus, Québec, Canada
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Parent A, Hazrati LN. Functional anatomy of the basal ganglia. II. The place of subthalamic nucleus and external pallidum in basal ganglia circuitry. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1995; 20:128-154. [PMID: 7711765 DOI: 10.1016/0165-0173(94)00008-d] [Citation(s) in RCA: 955] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The subthalamic nucleus and the external pallidum (GPe) are classically viewed as part of the so-called indirect pathway, which acts in concert with the direct pathway. The direct and indirect pathways form the conceptual framework of the anatomical and functional organization of the basal ganglia. A review of recent data regarding the connections of the subthalamic nucleus and the GPe has revealed a lack of firm anatomical support for the existence of the indirect pathway. However, newly recognized projections of the subthalamic nucleus and the GPe place these structures on various novel routes that change the conceptual architecture of the basal ganglia circuitry. These new findings force us to modify our view of the functional identity of the subthalamic nucleus and the GPe. In this new perspective, the GPe stands as an additional integrative station, together with the striatum and the internal pallidum and substantia nigra pars reticulata (GPi/SNr), along the main steam of information processing within the basal ganglia circuitry. Because of its crucial position between the input and output stations of the basal ganglia, the GPe can markedly influence the neuronal computation that occurs at GPi/SNr levels. The subthalamic nucleus can still be regarded as a 'control structure' lying alongside the main stream of information processing. However, because of its widespread efferent projections, the subthalamic nucleus exerts its driving effect on most components of the basal ganglia. Its action is mediated not only by the indirect pathway, but by a multitude of mono- and polysynaptic projections that ultimately reach the basal ganglia output cells.
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Affiliation(s)
- A Parent
- Centre de recherche en neurobiologie, Hôpital de l'Enfant-Jésus, Québec, QC, Canada
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Abstract
To add to our understanding of the anatomical organization of the globus pallidus (GP) of the rat, a light and electron microscopic analysis of parvalbumin (PV, a Ca-binding protein) immunoreactive neurons in the GP was performed. Light microscopic analysis revealed that the GP contains PV-positive and PV-negative neurons. Approximately two-thirds of the GP neurons were PV-positive. The somata of PV-positive neurons were, on average, larger than PV-negative ones. The proximal dendrites of PV-positive neurons were smooth and often lay parallel to the border between the GP and the neostriatum. Distal dendrites of PV-positive neurons were varicose. Thin PV-positive fibers with large boutons (with average diameter of 1.7 microns) were observed in the neuropil of the GP. Some PV-positive boutons formed basket-like aggregates surrounding the somata of PV-positive or negative neurons. Electron microscopic observations revealed that PV-positive neurons were often large and contained deeply indented nuclei and a large volume of cytoplasm. PV-negative neurons had smaller somata that were occupied by deeply indented nuclei and a small volume of cytoplasm. Both PV-positive and negative neurons were contacted by synaptic boutons identical to the known striato-pallidal, subthalamo-pallidal, and local collateral boutons. The PV-positive boutons contained small round or elongated vesicles and often more than one mitochondrion. Most of the boutons (i.e. 86%) formed symmetric synapses with somata and large dendrites and, the other (14%) formed asymmetric synapses with small dendrites. The study indicated that GP projection neurons can be divided into two subgroups according to their PV-immunoreactivity. PV-positive and negative neurons received similar extrinsic synaptic inputs and both types of neurons were connected through their local collateral axons. It is conceivable that the physiology of PV-positive and negative neurons might be different because of a difference in the Ca-buffering mechanisms in these neurons.
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Affiliation(s)
- H Kita
- University of Tennessee at Memphis, College of Medicine, Department of Anatomy and Neurobiology 38163
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Naito A, Kita H. The cortico-pallidal projection in the rat: an anterograde tracing study with biotinylated dextran amine. Brain Res 1994; 653:251-7. [PMID: 7526961 DOI: 10.1016/0006-8993(94)90397-2] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The projections from the frontal cortex to the pallidum (e.g. the globus pallidus and the entopeduncular nucleus) were studied in the rat using the biotinylated dextran amine (BDA) anterograde tracing method. Injections of BDA into the precentral medial and precentral lateral cortices consistently yielded labeling of thin fibers with small boutons in the ipsilateral pallidum although not in the contralateral pallidum. Electron microscopic observation revealed that BDA-labeled boutons form asymmetric synapses mainly with small dendrites and dendritic spines. When the injection sites included the insular, orbital, and prelimbic cortices, the labeled fibers and boutons were also seen in the ventral pallidum, the basal nucleus of Meynert, and the substantia innominata. Injections of BDA in the parietal and occipital cortices resulted in either very few labeling or no labeled boutons in the pallidum. The cortico-pallidal projections were topographically organized. The density of labeled boutons in the globus pallidus was found to be approximately 10% of the density of cortical terminals in the neostriatum.
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Affiliation(s)
- A Naito
- University of Tennessee, College of Medicine, Department of Anatomy and Neurobiology, Memphis 38163
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