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Cola RB, Roccaro-Waldmeyer DM, Naim S, Babalian A, Seebeck P, Alvarez-Bolado G, Celio MR. Chemo- and optogenetic activation of hypothalamic Foxb1-expressing neurons and their terminal endings in the rostral-dorsolateral PAG leads to tachypnea, bradycardia, and immobility. eLife 2024; 12:RP86737. [PMID: 38300670 PMCID: PMC10945554 DOI: 10.7554/elife.86737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
Foxb1 -expressing neurons occur in the dorsal premammillary nucleus (PMd) and further rostrally in the parvafox nucleus, a longitudinal cluster of neurons in the lateral hypothalamus of rodents. The descending projection of these Foxb1+ neurons end in the dorsolateral part of the periaqueductal gray (dlPAG). The functional role of the Foxb1+ neuronal subpopulation in the PMd and the parvafox nucleus remains elusive. In this study, the activity of the Foxb1+ neurons and of their terminal endings in the dlPAG in mice was selectively altered by employing chemo- and optogenetic tools. Our results show that in whole-body barometric plethysmography, hM3Dq-mediated, global Foxb1+ neuron excitation activates respiration. Time-resolved optogenetic gain-of-function manipulation of the terminal endings of Foxb1+ neurons in the rostral third of the dlPAG leads to abrupt immobility and bradycardia. Chemogenetic activation of Foxb1+ cell bodies and ChR2-mediated excitation of their axonal endings in the dlPAG led to a phenotypical presentation congruent with a 'freezing-like' situation during innate defensive behavior.
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Affiliation(s)
- Reto B Cola
- Anatomy and program in Neuroscience, Faculty of Science and Medicine, University of FribourgFribourgSwitzerland
| | - Diana M Roccaro-Waldmeyer
- Anatomy and program in Neuroscience, Faculty of Science and Medicine, University of FribourgFribourgSwitzerland
| | - Samara Naim
- Anatomy and program in Neuroscience, Faculty of Science and Medicine, University of FribourgFribourgSwitzerland
| | - Alexandre Babalian
- Anatomy and program in Neuroscience, Faculty of Science and Medicine, University of FribourgFribourgSwitzerland
| | - Petra Seebeck
- Zurich integrative Rodent Physiology (ZIRP), University of ZürichZürichSwitzerland
| | | | - Marco R Celio
- Anatomy and program in Neuroscience, Faculty of Science and Medicine, University of FribourgFribourgSwitzerland
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2
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Żakowski W, Zawistowski P. Neurochemistry of the mammillary body. Brain Struct Funct 2023; 228:1379-1398. [PMID: 37378855 PMCID: PMC10335970 DOI: 10.1007/s00429-023-02673-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 06/19/2023] [Indexed: 06/29/2023]
Abstract
The mammillary body (MB) is a component of the extended hippocampal system and many studies have shown that its functions are vital for mnemonic processes. Together with other subcortical structures, such as the anterior thalamic nuclei and tegmental nuclei of Gudden, the MB plays a crucial role in the processing of spatial and working memory, as well as navigation in rats. The aim of this paper is to review the distribution of various substances in the MB of the rat, with a description of their possible physiological roles. The following groups of substances are reviewed: (1) classical neurotransmitters (glutamate and other excitatory transmitters, gamma-aminobutyric acid, acetylcholine, serotonin, and dopamine), (2) neuropeptides (enkephalins, substance P, cocaine- and amphetamine-regulated transcript, neurotensin, neuropeptide Y, somatostatin, orexins, and galanin), and (3) other substances (calcium-binding proteins and calcium sensor proteins). This detailed description of the chemical parcellation may facilitate a better understanding of the MB functions and its complex relations with other structures of the extended hippocampal system.
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Affiliation(s)
- Witold Żakowski
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
| | - Piotr Zawistowski
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
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3
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Baliellas DEM, Barros MP, Vardaris CV, Guariroba M, Poppe SC, Martins MF, Pereira ÁAF, Bondan EF. Propentofylline Improves Thiol-Based Antioxidant Defenses and Limits Lipid Peroxidation following Gliotoxic Injury in the Rat Brainstem. Biomedicines 2023; 11:1652. [PMID: 37371747 DOI: 10.3390/biomedicines11061652] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Propentofylline (PROP) is a methylated xanthine compound that diminishes the activation of microglial cells and astrocytes, which are neuronal cells strongly associated with many neurodegenerative diseases. Based on previously observed remyelination and neuroprotective effects, PROP has also been proposed to increment antioxidant defenses and to prevent oxidative damage in neural tissues. Since most neurodegenerative processes have free radicals as molecular pathological agents, the aim of this study was to evaluate the antioxidant effects of 12.5 mg·kg-1·day-1 PROP in plasma and the brainstem of Wistar rats exposed to the gliotoxic agent 0.1% ethidium bromide (EB) for 7-31 days. The bulk of the data here demonstrates that, after 7 days of EB treatment, TBARS levels were 2-fold higher in the rat CNS than in control, reaching a maximum of 2.4-fold within 15 days. After 31 days of EB treatment, lipoperoxidation in CNS was still 65% higher than that in the control. Clearly, PROP treatment limited the progression of lipoperoxidation in EB-oxidized CNS: it was, for example, 76% lower than in the EB-treated group after 15 days. Most of these effects were associated with PROP-induced activity of glutathione reductase in the brainstem: the EB + PROP group showed 59% higher GR activity than that of the EB or control groups within 7 days. In summary, aligning with previous studies from our group and with literature about MTXs, we observed that propentofylline (PROP) improved the thiol-based antioxidant defenses in the rat brainstem by the induction of the enzymatic activity of glutathione reductase (GR), which diminished lipid oxidation progression and rebalanced the redox status in the CNS.
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Affiliation(s)
- Deborah E M Baliellas
- Department of Veterinary Medicine, Cruzeiro do Sul University, São Paulo 08060070, Brazil
| | - Marcelo P Barros
- Interdisciplinary Programs in Health Sciences, Institute of Physical Activity and Sport Sciences (ICAFE), Cruzeiro do Sul University, São Paulo 01506000, Brazil
| | - Cristina V Vardaris
- Interdisciplinary Programs in Health Sciences, Institute of Physical Activity and Sport Sciences (ICAFE), Cruzeiro do Sul University, São Paulo 01506000, Brazil
| | - Maísa Guariroba
- Department of Veterinary Medicine, Cruzeiro do Sul University, São Paulo 08060070, Brazil
- Interdisciplinary Programs in Health Sciences, Institute of Physical Activity and Sport Sciences (ICAFE), Cruzeiro do Sul University, São Paulo 01506000, Brazil
| | - Sandra C Poppe
- Department of Veterinary Medicine, Cruzeiro do Sul University, São Paulo 08060070, Brazil
| | - Maria F Martins
- Department of Veterinary Medicine, Cruzeiro do Sul University, São Paulo 08060070, Brazil
- Graduate Program in Environmental and Experimental Pathology, University Paulista (UNIP), São Paulo 04057000, Brazil
| | - Álvaro A F Pereira
- Department of Veterinary Medicine, Cruzeiro do Sul University, São Paulo 08060070, Brazil
| | - Eduardo F Bondan
- Graduate Program in Environmental and Experimental Pathology, University Paulista (UNIP), São Paulo 04057000, Brazil
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4
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Huang WC, Peng Z, Murdock MH, Liu L, Mathys H, Davila-Velderrain J, Jiang X, Chen M, Ng AP, Kim T, Abdurrob F, Gao F, Bennett DA, Kellis M, Tsai LH. Lateral mammillary body neurons in mouse brain are disproportionately vulnerable in Alzheimer's disease. Sci Transl Med 2023; 15:eabq1019. [PMID: 37075128 PMCID: PMC10511020 DOI: 10.1126/scitranslmed.abq1019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/31/2023] [Indexed: 04/21/2023]
Abstract
The neural circuits governing the induction and progression of neurodegeneration and memory impairment in Alzheimer's disease (AD) are incompletely understood. The mammillary body (MB), a subcortical node of the medial limbic circuit, is one of the first brain regions to exhibit amyloid deposition in the 5xFAD mouse model of AD. Amyloid burden in the MB correlates with pathological diagnosis of AD in human postmortem brain tissue. Whether and how MB neuronal circuitry contributes to neurodegeneration and memory deficits in AD are unknown. Using 5xFAD mice and postmortem MB samples from individuals with varying degrees of AD pathology, we identified two neuronal cell types in the MB harboring distinct electrophysiological properties and long-range projections: lateral neurons and medial neurons. lateral MB neurons harbored aberrant hyperactivity and exhibited early neurodegeneration in 5xFAD mice compared with lateral MB neurons in wild-type littermates. Inducing hyperactivity in lateral MB neurons in wild-type mice impaired performance on memory tasks, whereas attenuating aberrant hyperactivity in lateral MB neurons ameliorated memory deficits in 5xFAD mice. Our findings suggest that neurodegeneration may be a result of genetically distinct, projection-specific cellular dysfunction and that dysregulated lateral MB neurons may be causally linked to memory deficits in AD.
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Affiliation(s)
- Wen-Chin Huang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Zhuyu Peng
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Mitchell H. Murdock
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Liwang Liu
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Hansruedi Mathys
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard; Cambridge, MA, 02139, USA
| | - Jose Davila-Velderrain
- Broad Institute of MIT and Harvard; Cambridge, MA, 02139, USA
- MIT Computer Science and Artificial Intelligence Laboratory; Cambridge, MA 02139, USA
| | - Xueqiao Jiang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Maggie Chen
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Ayesha P. Ng
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - TaeHyun Kim
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Fatema Abdurrob
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - Fan Gao
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
| | - David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center; Chicago, IL 60612, USA
| | - Manolis Kellis
- Broad Institute of MIT and Harvard; Cambridge, MA, 02139, USA
- MIT Computer Science and Artificial Intelligence Laboratory; Cambridge, MA 02139, USA
| | - Li-Huei Tsai
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology; Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard; Cambridge, MA, 02139, USA
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5
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Understanding the Significance of the Hypothalamic Nature of the Subthalamic Nucleus. eNeuro 2021; 8:ENEURO.0116-21.2021. [PMID: 34518367 PMCID: PMC8493884 DOI: 10.1523/eneuro.0116-21.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 08/05/2021] [Accepted: 08/20/2021] [Indexed: 11/21/2022] Open
Abstract
The subthalamic nucleus (STN) is an essential component of the basal ganglia and has long been considered to be a part of the ventral thalamus. However, recent neurodevelopmental data indicated that this nucleus is of hypothalamic origin which is now commonly acknowledged. In this work, we aimed to verify whether the inclusion of the STN in the hypothalamus could influence the way we understand and conduct research on the organization of the whole ventral and posterior diencephalon. Developmental and neurochemical data indicate that the STN is part of a larger glutamatergic posterior hypothalamic region that includes the premammillary and mammillary nuclei. The main anatomic characteristic common to this region involves the convergent cortical and pallidal projections that it receives, which is based on the model of the hyperdirect and indirect pathways to the STN. This whole posterior hypothalamic region is then integrated into distinct functional networks that interact with the ventral mesencephalon to adjust behavior depending on external and internal contexts.
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6
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Hou Y, Zhang Q, Liu H, Wu J, Shi Y, Qi Y, Shao M, Yang Z, Lu J, Wu Z, Gong L, He M. Topographical organization of mammillary neurogenesis and efferent projections in the mouse brain. Cell Rep 2021; 34:108712. [PMID: 33567285 DOI: 10.1016/j.celrep.2021.108712] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/01/2020] [Accepted: 01/12/2021] [Indexed: 01/23/2023] Open
Abstract
The mammillary body is a hypothalamic nucleus that has important functions in memory and spatial navigation, but its developmental principles remain not well understood. Here, we identify progenitor-specific Fezf2 expression in the developing mammillary body and develop an intersectional fate-mapping approach to demonstrate that Fezf2+ mammillary progenitors generate mammillary neurons in a rostral-dorsal-lateral to caudal-ventral-medial fashion. Axonal tracing from different temporal cohorts of labeled mammillary neurons reveal their topographical organization. Unsupervised hierarchical clustering based on intrinsic properties further identify two distinct neuronal clusters independent of birthdates in the medial nuclei. In addition, we generate Fezf2 knockout mice and observe the smaller mammillary body with largely normal anatomy and mildly affected cellular electrophysiology, in contrast to more severe deficits in neuronal differentiation and projection in many other brain regions. These results indicate that Fezf2 may function differently in the mammillary body. Our results provide important insights for mammillary development and connectivity.
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Affiliation(s)
- Yongjie Hou
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qi Zhang
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Hongzhi Liu
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jinyun Wu
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yun Shi
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yanqing Qi
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Mengmeng Shao
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhengang Yang
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jiangteng Lu
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhuhao Wu
- Department of Cell, Developmental and Regenerative Biology, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ling Gong
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Miao He
- Institutes of Brain Science, Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China.
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7
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Cai ZJ. The limbic-reticular coupling theory of memory processing in the brain and its greater compatibility over other theories. Dement Neuropsychol 2018; 12:105-113. [PMID: 29988336 PMCID: PMC6022992 DOI: 10.1590/1980-57642018dn12-020002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The limbic-reticular coupling theory suggests that the hippocampus and amygdala regulate such descending limbic structures as the mammillary bodies, septum, hypothalamus and epithalamus to regulate the ascending noradrenergic, serotonergic, dopaminergic and cholinergic systems, performing declarative memory consolidation and recall. Recent studies have revealed that, less sensitive to familiarity, the hippocampus functions via the fornix, mammillary bodies and hypothalamus for memory recall. Lesions to the thalamic nuclei were complicated with damage to adjacent fornix, stria medullaris and habenula, simultaneously destroying two kinds of structures respectively for familiarity and recall. Furthermore, the orbitofrontal cortex was shown to be clinically irrelevant for memory recall. Electrophysiologically, the hippocampus regulates the raphe nuclei in complex ways, and the hippocampal theta wave activates the dopaminergic cells in ventral tegmental area and cholinergic neurons in basal forebrain, while cholinergic-modulated theta-gamma coupling mediates cortical recall. These concurrent advances support the limbic-reticular coupling theory for elucidation of memory recall.
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Affiliation(s)
- Zi-Jian Cai
- CaiFortune Consulting, República Popular da China
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8
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Benagiano V, Rizzi A, Lorusso L, Flace P, Saccia M, Cagiano R, Ribatti D, Roncali L, Ambrosi G. The functional anatomy of the cerebrocerebellar circuit: A review and new concepts. J Comp Neurol 2017; 526:769-789. [PMID: 29238972 DOI: 10.1002/cne.24361] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 11/03/2017] [Accepted: 11/06/2017] [Indexed: 12/19/2022]
Abstract
The cerebrocerebellar circuit is a feedback circuit that bidirectionally connects the neocortex and the cerebellum. According to the classic view, the cerebrocerebellar circuit is specifically involved in the functional regulation of the motor areas of the neocortex. In recent years, studies carried out in experimental animals by morphological and physiological methods, and in humans by magnetic resonance imaging, have indicated that the cerebrocerebellar circuit is also involved in the functional regulation of the nonmotor areas of the neocortex, including the prefrontal, associative, sensory and limbic areas. Moreover, a second type of cerebrocerebellar circuit, bidirectionally connecting the hypothalamus and the cerebellum, has been detected, being specifically involved in the regulation of the hypothalamic functions. This review analyzes the morphological features of the centers and pathways of the cerebrocerebellar circuits, paying particular attention to their organization in different channels, which separately connect the cerebellum with the motor areas and nonmotor areas of the neocortex, and with the hypothalamus. Actually, a considerable amount of new data have led, and are leading, to profound changes on the views on the anatomy, physiology, and pathophysiology of the cerebrocerebellar circuits, so much they may be now considered to be essential for the functional regulation of many neocortex areas, perhaps all, as well as of the hypothalamus and of the limbic system. Accordingly, clinical studies have pointed out an involvement of the cerebrocerebellar circuits in the pathophysiology of an increasing number of neuropsychiatric disorders.
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Affiliation(s)
- Vincenzo Benagiano
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Anna Rizzi
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Loredana Lorusso
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Paolo Flace
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Matteo Saccia
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Raffaele Cagiano
- Department of Biomedical Sciences and Human Oncology, University of Bari, Bari, Italy
| | - Domenico Ribatti
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy.,National Cancer Institute 'Giovanni Paolo II', Bari, Italy
| | - Luisa Roncali
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
| | - Glauco Ambrosi
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, University of Bari, Bari, Italy
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9
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Mammillothalamic and Mammillotegmental Tracts as New Targets for Dementia and Epilepsy Treatment. World Neurosurg 2017; 110:133-144. [PMID: 29129763 DOI: 10.1016/j.wneu.2017.10.168] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 01/24/2023]
Abstract
BACKGROUND Recently, neuromodulation through deep brain stimulation (DBS) has appeared as a new surgical procedure in the treatment of some types of dementia and epilepsy. The mammillothalamic and mammillotegmental tracts are involved among the new targets. To our knowledge, a review article focused specifically on these mammillary body efferents is lacking in the medical literature. Their contribution to memory is, regrettably, often overlooked. METHODS A review of the relevant literature was conducted. RESULTS There is evidence that mammillary bodies can contribute to memory independently from hippocampal formation, but the mechanism is not yet known. Recent studies in animals have provided evidence for the specific roles of these mammillary body efferents in regulating memory independently. In animal studies, it has been shown that the disruption of the mammillothalamic tract inhibits seizures and that electrical stimulation of the mammillary body or mammillothalamic tract raises the seizure threshold. In humans, DBS targeting the mammillary body through the mammillothalamic tract or the stimulation of the anterior thalamic nucleus, especially in the areas closely related to the mammillothalamic tract, has been found effective in patients with medically refractory epilepsy. Nonetheless, little knowledge exists on the functional anatomy of the mammillary body efferents, and their role in the exact mechanism of epileptogenic activity and in the memory function of the human brain. CONCLUSIONS A comprehensive knowledge of the white matter anatomy of the mammillothalamic and mammillotegmental tracts is crucial since they have emerged as new DBS targets in the treatment of various disorders including dementia and epilepsy.
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10
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Vertes RP, Hoover WB, Viana Di Prisco G. Theta Rhythm of the Hippocampus: Subcortical Control and Functional Significance. ACTA ACUST UNITED AC 2016; 3:173-200. [PMID: 15653814 DOI: 10.1177/1534582304273594] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The theta rhythm is the largest extracellular synchronous signal that can be recorded from the mammalian brain and has been strongly implicated in mnemonic processes of the hippocampus. We describe (a) ascending brain stem–forebrain systems involved in controlling theta and nontheta (desynchronization) states of the hippocampal electroencephalogram; (b) theta rhythmically discharging cells in several structures of Papez's circuit and their possible functional significance, specifically with respect to head direction cells in this same circuit; and (c) the role of nucleus reuniens of the thalamus as a major interface between the medial prefrontal cortex and hippocampus and as a prominent source of afferent limbic information to the hippocampus. We suggest that the hippocampus receives two main types of input: theta rhythm from ascending brain stem– diencephaloseptal systems and information bearing mainly from thalamocortical/cortical systems. The temporal convergence of activity of these two systems results in the encoding of information in the hippocampus, primarily reaching it from the entorhinal cortex and nucleus reuniens.
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11
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Brown RE, McKenna JT. Turning a Negative into a Positive: Ascending GABAergic Control of Cortical Activation and Arousal. Front Neurol 2015; 6:135. [PMID: 26124745 PMCID: PMC4463930 DOI: 10.3389/fneur.2015.00135] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/28/2015] [Indexed: 01/01/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain. Recent technological advances have illuminated the role of GABAergic neurons in control of cortical arousal and sleep. Sleep-promoting GABAergic neurons in the preoptic hypothalamus are well-known. Less well-appreciated are GABAergic projection neurons in the brainstem, midbrain, hypothalamus, and basal forebrain, which paradoxically promote arousal and fast electroencephalographic (EEG) rhythms. Thus, GABA is not purely a sleep-promoting neurotransmitter. GABAergic projection neurons in the brainstem nucleus incertus and ventral tegmental nucleus of Gudden promote theta (4-8 Hz) rhythms. Ventral tegmental area GABAergic neurons, neighboring midbrain dopamine neurons, project to the frontal cortex and nucleus accumbens. They discharge faster during cortical arousal and regulate reward. Thalamic reticular nucleus GABAergic neurons initiate sleep spindles in non-REM sleep. In addition, however, during wakefulness, they tonically regulate the activity of thalamocortical neurons. Other GABAergic inputs to the thalamus arising in the globus pallidus pars interna, substantia nigra pars reticulata, zona incerta, and basal forebrain regulate motor activity, arousal, attention, and sensory transmission. Several subpopulations of cortically projecting GABAergic neurons in the basal forebrain project to the thalamus and neocortex and preferentially promote cortical gamma-band (30-80 Hz) activity and wakefulness. Unlike sleep-active GABAergic neurons, these ascending GABAergic neurons are fast-firing neurons which disinhibit and synchronize the activity of their forebrain targets, promoting the fast EEG rhythms typical of conscious states. They are prominent targets of GABAergic hypnotic agents. Understanding the properties of ascending GABAergic neurons may lead to novel treatments for diseases involving disorders of cortical activation and wakefulness.
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Affiliation(s)
- Ritchie E Brown
- Laboratory of Neuroscience, Department of Psychiatry, VA Boston Healthcare System, Harvard Medical School , Brockton, MA , USA
| | - James T McKenna
- Laboratory of Neuroscience, Department of Psychiatry, VA Boston Healthcare System, Harvard Medical School , Brockton, MA , USA
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12
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Makarenko IG. DiI tracing of the hypothalamic projection systems during perinatal development. Front Neuroanat 2014; 8:144. [PMID: 25538571 PMCID: PMC4255665 DOI: 10.3389/fnana.2014.00144] [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: 09/27/2014] [Accepted: 11/13/2014] [Indexed: 01/20/2023] Open
Abstract
The hypothalamus is the higher neuroendocrine center of the brain and therefore possesses numerous intrinsic axonal connections and is connected by afferent and efferent fiber systems with other brain structures. These projection systems have been described in detail in the adult but data on their early development is sparse. Here I review studies of the time schedule and features of the development of the major hypothalamic axonal systems. In general, anterograde tracing experiments have been used to analyze short distance projections from the arcuate and anteroventral periventricular nuclei (Pe), while hypothalamic projections to the posterior and intermediate pituitary lobes (IL) and median eminence, mammillary body tracts and reciprocal septohypothalamic connections have been described with retrograde tracing. The available data demonstrate that hypothalamic connections develop with a high degree of spatial and temporal specificity, innervating each target with a unique developmental schedule which in many cases can be correlated with the functional maturity of the projection system.
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Affiliation(s)
- Irina G. Makarenko
- Laboratory of Cellular and Molecular Basis of Histogenesis, Koltzov Institute of Developmental Biology, Russian Academy of SciencesMoscow, Russia
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Dillingham CM, Frizzati A, Nelson AJD, Vann SD. How do mammillary body inputs contribute to anterior thalamic function? Neurosci Biobehav Rev 2014; 54:108-19. [PMID: 25107491 PMCID: PMC4462591 DOI: 10.1016/j.neubiorev.2014.07.025] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/18/2014] [Accepted: 07/28/2014] [Indexed: 11/25/2022]
Abstract
It has long been assumed that the main function of the mammillary bodies is to provide a relay for indirect hippocampal inputs to the anterior thalamic nuclei. Such models afford the mammillary bodies no independent role in memory and overlook the importance of their other, non-hippocampal, inputs. This review focuses on recent advances that herald a new understanding of the importance of the mammillary bodies, and their inputs from the limbic midbrain, for anterior thalamic function. It has become apparent that the mammillary bodies' contribution to memory is not dependent on afferents from the subicular complex. Rather, the ventral tegmental nucleus of Gudden is a vital source of inputs that support memory processes within the medial mammillary bodies. In parallel, the lateral mammillary bodies, via their connections with the dorsal tegmental nucleus of Gudden, are critical for generating head-direction signals. These two parallel, but distinct, information streams converge on the anterior thalamic nuclei and support different aspects of spatial memory.
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Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Aura Frizzati
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Andrew J D Nelson
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, United Kingdom.
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14
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Kocsis B, Di Prisco GV, Vertes RP. Theta synchronization in the limbic system: the role of Gudden's tegmental nuclei. Eur J Neurosci 2011. [DOI: 10.1111/j.1460-9568.2001.tb01708.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Pignatelli M, Beyeler A, Leinekugel X. Neural circuits underlying the generation of theta oscillations. ACTA ACUST UNITED AC 2011; 106:81-92. [PMID: 21964249 DOI: 10.1016/j.jphysparis.2011.09.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 01/24/2023]
Abstract
Theta oscillations represent the neural network configuration underlying active awake behavior and paradoxical sleep. This major EEG pattern has been extensively studied, from physiological to anatomical levels, for more than half a century. Nevertheless the cellular and network mechanisms accountable for the theta generation are still not fully understood. This review synthesizes the current knowledge on the circuitry involved in the generation of theta oscillations, from the hippocampus to extra hippocampal structures such as septal complex, entorhinal cortex and pedunculopontine tegmentum, a main trigger of theta state through direct and indirect projections to the septal complex. We conclude with a short overview of the perspectives offered by technical advances for deciphering more precisely the different neural components underlying the emergence of theta oscillations.
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Affiliation(s)
- Michele Pignatelli
- Institut des Maladies Neurodégénératives, UMR 5293, CNRS and Université Bordeaux 1 & 2, Avenue des Facultés, Bat B2, Talence, France.
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16
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Mammillotegmental tract in the human brain: diffusion tensor tractography study. Neuroradiology 2011; 53:623-6. [DOI: 10.1007/s00234-011-0858-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 03/02/2011] [Indexed: 11/27/2022]
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17
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Vann SD. Re-evaluating the role of the mammillary bodies in memory. Neuropsychologia 2009; 48:2316-27. [PMID: 19879886 DOI: 10.1016/j.neuropsychologia.2009.10.019] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 10/20/2022]
Abstract
Although the mammillary bodies were among the first brain regions to be implicated in amnesia, the functional importance of this structure for memory has been questioned over the intervening years. Recent patient studies have, however, re-established the mammillary bodies, and their projections to the anterior thalamus via the mammillothalamic tract, as being crucial for recollective memory. Complementary animal research has also made substantial advances in recent years by determining the electrophysiological, neurochemical, anatomical and functional properties of the mammillary bodies. Mammillary body and mammillothalamic tract lesions in rats impair performance on a number of spatial memory tasks and these deficits are consistent with impoverished spatial encoding. The mammillary bodies have traditionally been considered a hippocampal relay which is consistent with the equivalent deficits seen following lesions of the mammillary bodies or their major efferents, the mammillothalamic tract. However, recent findings suggest that the mammillary bodies may have a role in memory that is independent of their hippocampal formation afferents; instead, the ventral tegmental nucleus of Gudden could be providing critical mammillary body inputs needed to support mnemonic processes. Finally, it is now apparent that the medial and lateral mammillary nuclei should be considered separately and initial research indicates that the medial mammillary nucleus is predominantly responsible for the spatial memory deficits following mammillary body lesions in rats.
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Affiliation(s)
- Seralynne D Vann
- School of Psychology, Cardiff University, Tower Building, Cardiff, UK.
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Tsuchiya R, Takahashi K, Liu FC, Takahashi H. Aberrant axonal projections from mammillary bodies in Pax6 mutant mice: possible roles of Netrin-1 and Slit 2 in mammillary projections. J Neurosci Res 2009; 87:1620-33. [PMID: 19115401 DOI: 10.1002/jnr.21966] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Early events in the axonal tract formation from mammillary bodies remain poorly understood. In the present study, we reported an aberrant pattern of axonal projections from mammillary bodies to the dorsal thalamus in mice lacking the transcription factor Pax6. We found that Netrin-1 was ectopically up-regulated and that both Slit1 and Slit2 were down-regulated in the presumptive dorsal thalamus of Pax6 mutant mice. We then examined the effects of Netrin-1 and Slit2 on the mammillary axons by in utero electroporation techniques. Netrin-1 had an attractive action toward the mammillary axons. Moreover, mammillary trajectories were disorganized in Netrin-1-deficient mice. On the other hand, Slit2 had a repulsive effect on the mammillary axons. These findings suggest that the combination of Netrin and Slit may be involved in proper axonal projection from the mammillary bodies and that their misexpression in the diencephalon may cause the misrouting of these axons in Pax6 mutant mice.
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Affiliation(s)
- Reiko Tsuchiya
- Developmental Neurobiology Group, Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
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Bassett JP, Tullman ML, Taube JS. Lesions of the tegmentomammillary circuit in the head direction system disrupt the head direction signal in the anterior thalamus. J Neurosci 2007; 27:7564-77. [PMID: 17626218 PMCID: PMC6672597 DOI: 10.1523/jneurosci.0268-07.2007] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 05/09/2007] [Accepted: 05/28/2007] [Indexed: 11/21/2022] Open
Abstract
Head direction (HD) cells in the rodent limbic system are believed to correspond to a cognitive representation of directional heading in the environment. Lesions of vestibular hair cells disrupt the characteristic firing patterns of HD cells, and thus vestibular afference is a critical contributor to the HD signal. A subcortical pathway that may convey this information includes the dorsal tegmental nucleus of Gudden (DTN) and the lateral mammillary nucleus (LMN). To test the hypothesis that the DTN and LMN are critical components for generating HD cell activity, we made electrolytic lesions of the DTN or LMN in rats and screened for HD cell activity in the anterior thalamus. Directional activity was absent in all animals with complete LMN lesions and in animals with complete DTN lesions, although a few HD cells were isolated in animals with incomplete lesions. Some DTN-lesioned animals contained cells whose firing rates were modulated by angular head velocity. Although cells with bursting patterns of activity have been observed in the anterior dorsal nucleus of the thalamus of animals with disruption of vestibular inputs, this pattern of activity was not observed in either the LMN- or DTN-lesioned animals. The general absence of direction-specific activity in the anterior thalamus of animals with DTN or LMN lesions is consistent with the view that the DTN-LMN circuit is essential for the generation of HD cell activity.
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Affiliation(s)
- Joshua P. Bassett
- Department of Psychological and Brain Sciences, Center for Cognitive Neuroscience, Dartmouth College, Hanover, New Hampshire 03755
| | - Matthew L. Tullman
- Department of Psychological and Brain Sciences, Center for Cognitive Neuroscience, Dartmouth College, Hanover, New Hampshire 03755
| | - Jeffrey S. Taube
- Department of Psychological and Brain Sciences, Center for Cognitive Neuroscience, Dartmouth College, Hanover, New Hampshire 03755
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20
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Alpeeva EV, Makarenko IG. Perinatal development of mammillotegmental connections in rats. Russ J Dev Biol 2007. [DOI: 10.1134/s1062360407020026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Marion JF, Yang C, Caqueret A, Boucher F, Michaud JL. Sim1 and Sim2 are required for the correct targeting of mammillary body axons. Development 2005; 132:5527-37. [PMID: 16291793 DOI: 10.1242/dev.02142] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mammillary body (MB), and its axonal projections to the thalamus (mammillothalamic tract, MTT) and the tegmentum (mammillotegmental tract, MTEG), are components of a circuit involved in spatial learning. The bHLH-PAS transcription factors SIM1 and SIM2 are co-expressed in the developing MB. We have found that MB neurons are generated and that they survive at least until E18.5 in embryos lacking both Sim1 and Sim2 (Sim1(-/-);Sim2(-/-)). However, the MTT and MTEG are histologically absent in Sim1(-/-);Sim2(-/-) embryos, and are reduced in embryos lacking Sim1 but bearing one or two copies of Sim2, indicating a contribution of the latter to the development of MB axons. We have generated, by homologous recombination, a null allele of Sim1 (Sim1(tlz)) in which the tau-lacZ fusion gene was introduced, allowing the staining of MB axons. Consistent with the histological studies, lacZ staining showed that the MTT/MTEG is barely detectable in Sim1(tlz/tlz);Sim2(+/-) and Sim1(tlz/tlz);Sim2(-/-) brains. Instead, MB axons are splayed and grow towards the midline. Slit1 and Slit2, which code for secreted molecules that induce the repulsion of ROBO1-producing axons, are expressed in the midline at the level of the MB, whereas Robo1 is expressed in the developing MB. The expression of Rig-1/Robo3, a negative regulator of Slit signalling, is upregulated in the prospective MB of Sim1/Sim2 double mutants, raising the possibility that the growth of mutant MB axons towards the midline is caused by a decreased sensitivity to SLIT. Finally, we found that Sim1 and Sim2 act along compensatory, but not hierarchical, pathways, suggesting that they play similar roles in vivo.
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Affiliation(s)
- Jean-François Marion
- Research Center, Hôpital Sainte-Justine, 3175 Cote Ste-Catherine, Montréal, Quebec H3T 1C5, Canada
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Song P, Wang XJ. Angular path integration by moving "hill of activity": a spiking neuron model without recurrent excitation of the head-direction system. J Neurosci 2005; 25:1002-14. [PMID: 15673682 PMCID: PMC6725619 DOI: 10.1523/jneurosci.4172-04.2005] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During spatial navigation, the head orientation of an animal is encoded internally by neural persistent activity in the head-direction (HD) system. In computational models, such a bell-shaped "hill of activity" is commonly assumed to be generated by recurrent excitation in a continuous attractor network. Recent experimental evidence, however, indicates that HD signal in rodents originates in a reciprocal loop between the lateral mammillary nucleus (LMN) and the dorsal tegmental nucleus (DTN), which is characterized by a paucity of local excitatory axonal collaterals. Moreover, when the animal turns its head to a new direction, the heading information is updated by a time integration of angular head velocity (AHV) signals; the underlying mechanism remains unresolved. To investigate these issues, we built and investigated an LMN-DTN network model that consists of three populations of noisy and spiking neurons coupled by biophysically realistic synapses. We found that a combination of uniform external excitation and recurrent cross-inhibition can give rise to direction-selective persistent activity. The model reproduces the experimentally observed three types of HD tuning curves differentially modulated by AHV and anticipatory firing activity in LMN HD cells. Time integration is assessed by using constant or sinusoidal angular velocity stimuli, as well as naturalistic AHV inputs (from rodent recordings). Furthermore, the internal representation of head direction is shown to be calibrated or reset by strong external cues. We identify microcircuit properties that determine the ability of our model network to subserve time integration function.
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Affiliation(s)
- Pengcheng Song
- Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, USA
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23
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Boucheny C, Brunel N, Arleo A. A continuous attractor network model without recurrent excitation: maintenance and integration in the head direction cell system. J Comput Neurosci 2005; 18:205-27. [PMID: 15714270 DOI: 10.1007/s10827-005-6559-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Motivated by experimental observations of the head direction system, we study a three population network model that operates as a continuous attractor network. This network is able to store in a short-term memory an angular variable (the head direction) as a spatial profile of activity across neurons in the absence of selective external inputs, and to accurately update this variable on the basis of angular velocity inputs. The network is composed of one excitatory population and two inhibitory populations, with inter-connections between populations but no connections within the neurons of a same population. In particular, there are no excitatory-to-excitatory connections. Angular velocity signals are represented as inputs in one inhibitory population (clockwise turns) or the other (counterclockwise turns). The system is studied using a combination of analytical and numerical methods. Analysis of a simplified model composed of threshold-linear neurons gives the conditions on the connectivity for (i) the emergence of the spatially selective profile, (ii) reliable integration of angular velocity inputs, and (iii) the range of angular velocities that can be accurately integrated by the model. Numerical simulations allow us to study the proposed scenario in a large network of spiking neurons and compare their dynamics with that of head direction cells recorded in the rat limbic system. In particular, we show that the directional representation encoded by the attractor network can be rapidly updated by external cues, consistent with the very short update latencies observed experimentally by Zugaro et al. (2003) in thalamic head direction cells.
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Affiliation(s)
- Christian Boucheny
- Laboratory of Physiology of Perception and Action, CNRS-Collège de France, 11 pl. M. Berthelot, 75005, Paris, France
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24
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Affiliation(s)
- Seralynne D Vann
- School of Psychology, Cardiff University, PO Box 901, Cardiff CF10 3YG, UK.
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25
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Olucha-Bordonau FE, Teruel V, Barcia-González J, Ruiz-Torner A, Valverde-Navarro AA, Martínez-Soriano F. Cytoarchitecture and efferent projections of the nucleus incertus of the rat. J Comp Neurol 2003; 464:62-97. [PMID: 12866129 DOI: 10.1002/cne.10774] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The nucleus incertus is located caudal to the dorsal raphe and medial to the dorsal tegmentum. It is composed of a pars compacta and a pars dissipata and contains acetylcholinesterase, glutamic acid decarboxylase, and cholecystokinin-positive somata. In the present study, anterograde tracer injections in the nucleus incertus resulted in terminal-like labeling in the perirhinal cortex and the dorsal endopyriform nucleus, the hippocampus, the medial septum diagonal band complex, lateral and triangular septum medial amygdala, the intralaminar thalamic nuclei, and the lateral habenula. The hypothalamus contained dense plexuses of fibers in the medial forebrain bundle that spread in nearly all nuclei. Labeling in the suprachiasmatic nucleus filled specifically the ventral half. In the midbrain, labeled fibers were observed in the interpeduncular nuclei, ventral tegmental area, periaqueductal gray, superior colliculus, pericentral inferior colliculus, pretectal area, the raphe nuclei, and the nucleus reticularis pontis oralis. Retrograde tracer injections were made in areas reached by anterogradely labeled fibers including the medial prefrontal cortex, hippocampus, amygdala, habenula, nucleus reuniens, superior colliculus, periaqueductal gray, and interpeduncular nuclei. All these injections gave rise to retrograde labeling in the nucleus incertus but not in the dorsal tegmental nucleus. These data led us to conclude that there is a system of ascending projections arising from the nucleus incertus to the median raphe, mammillary complex, hypothalamus, lateral habenula, nucleus reuniens, amygdala, entorhinal cortex, medial septum, and hippocampus. Many of the targets of the nucleus incertus were involved in arousal mechanisms including the synchronization and desynchronization of the theta rhythm.
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Affiliation(s)
- Francisco E Olucha-Bordonau
- Department of Anatomy and Human Embryology, Faculty of Medicine and Odontology, University of Valencia, E-46010 Valencia, Spain.
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26
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Evidence of a spatial encoding deficit in rats with lesions of the mammillary bodies or mammillothalamic tract. J Neurosci 2003. [PMID: 12716960 DOI: 10.1523/jneurosci.23-08-03506.2003] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The present study sought to identify the role of the mammillary bodies and their projections to the anterior thalamic nuclei for spatial memory. Rats with either selective, neurotoxic mammillary body lesions or discrete mammillothalamic tract lesions were tested on various spatial working memory tasks. Tests using the T-maze, radial-arm maze, and water maze were manipulated to compare three possible theories of mammillary body function by increasing proactive interference, increasing retention interval, and taxing the rapid processing of novel spatial stimuli. On T-maze alternation and radial-arm maze tasks, both lesion groups were initially impaired but seemed to recover. Transfer tests revealed, however, a more permanent change in performance, suggesting a failure to use distal (allocentric) cues. Consistent with this, both groups were also impaired at matching-to-place in the water maze and showed little improvement with practice. Nevertheless, once the lesion groups had been trained on a task, they were not affected differentially either by an increase of proactive interference or by retention intervals of up to 30 min. Although both mammillary body and mammillothalamic tract lesions resulted in similar impairments, the mammillothalamic tract group was the more affected when acquiring new spatial information. Together, these results suggest that mammillary body damage causes an encoding deficit when learning new spatial tasks, resulting in a suboptimal mode of performance, which may reflect a loss of directional heading information.
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27
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Taymans JM, Wintmolders C, Te Riele P, Jurzak M, Groenewegen HJ, Leysen JE, Langlois X. Detailed localization of regulator of G protein signaling 2 messenger ribonucleic acid and protein in the rat brain. Neuroscience 2002; 114:39-53. [PMID: 12207953 DOI: 10.1016/s0306-4522(02)00260-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Regulator of G protein signaling (RGS) proteins are a recently identified family of proteins which dampen G protein-coupled receptor-mediated signaling by accelerating the intrinsic GTPase activity of Galpha subunits of heterotrimeric G proteins. More than 20 different RGSs have been identified and at least 10 are expressed in the CNS. The present study describes in detail the localization in the rat brain of one member of this family, RGS2. The distribution of RGS2 mRNA and protein has been studied in parallel by performing in situ hybridization and immunoautoradiography on adjacent rat brain sections. Our localization study reveals that RGS2 mRNA and protein are widely expressed in the brain. Protein and mRNA are mostly colocalized such as in neocortex, piriform cortex, caudate-putamen, septum, hippocampus, locus coeruleus. Some mismatches were also observed such as presence of mRNA but not protein in the paraventricular nucleus, the substantia nigra pars compacta and the red nucleus, suggesting that RGS2 protein is present in neuronal projections. Previous reports describing an induction of RGS2 mRNA in the rat striatum after psychostimulants (amphetamine, cocaine) led us to focus on the distribution of RGS2 in the basal ganglia circuitry. The absence of RGS2 mRNA and protein in the globus pallidus suggests that RGS2 would play its regulatory role more in the direct (striatonigral) than in the indirect (striatopallidal) striatal output pathway. In addition, to delineate the implication of RGS2 in pre- and/or postsynaptic functions in the basal ganglia, we performed lesions of the nigrostriatal pathway by 6-hydroxydopamine (6-OHDA) and striatal quinolinic acid lesions. The 6-OHDA lesion did not modify RGS2 mRNA or protein levels in the caudate-putamen whereas the intrastriatal quinolinic acid infusion caused a marked reduction of RGS2 mRNA and protein in the lesioned zone. These data indicate that RGS2 is predominantly expressed in intrinsic striatal neurons. Moreover, the absence of detectable change in RGS2 expression after injections of 6-OHDA suggests also that RGS2 is not primarily involved in the hypersensitization of postsynaptic dopamine receptors observed after lesion of the nigrostriatal pathway.
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Affiliation(s)
- J M Taymans
- CNS Discovery Research, Johnson & Johnson Pharmaceutical Research and Development, Turnhoutseweg 30, 2340 Beerse, Belgium
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Bassant MH, Poindessous-Jazat F. Sleep-related increase in activity of mesopontine neurons in old rats. Neurobiol Aging 2002; 23:615-24. [PMID: 12009510 DOI: 10.1016/s0197-4580(01)00339-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Relationships between age-related changes in sleep patterns and neuronal activity have received scant attention. In the present study, reticularis pontis oralis (RPO) and ventral tegmental nucleus of Gudden (VTN) neurons were recorded in unanesthetized restrained young (3 months) and old (23 months) Sprague-Dawley rats during wakefulness (W), slow wave sleep (SWS) and rapid eye movement (REM) sleep. All RPO neurons displayed a tonic activity. Firing rates were similar during W in young and old rats. In contrast, firing rates were higher during SWS in old rats (P < 0.001). In both young and old rats, firing rates increased significantly during REM sleep as compared to W and SWS but this increase was markedly greater in old rats. Neurons recorded from VTN displayed bursting activity at theta frequencies during W and REM sleep. The frequency of VTN bursting neurons was higher during REM sleep as compared to W in both groups of age. This difference was significantly more pronounced in old as compared to young rats (P < 0.001). Sleep-related hyperactivity of pontine neurons is discussed in terms of a possible deficit in inhibitory processes in old rats.
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Affiliation(s)
- M H Bassant
- Neurobiologie de la croissance et de la sénescence, INSERM U 549, 2 ter rue d'Alésia, 75014 Paris, France.
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29
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Bassant MH, Poindessous-Jazat F. Ventral tegmental nucleus of Gudden: a pontine hippocampal theta generator? Hippocampus 2002; 11:809-13. [PMID: 11811675 DOI: 10.1002/hipo.1096] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is well-established that rhythmically bursting (RB) activity in the medial septum is crucial for the generation of the hippocampal theta rhythm, but the contribution of other diencephalic-pontine structures is less documented. The ventral tegmental nucleus (VTn) of Gudden is related to the Papez's circuit via its interconnections with the medial mammillary nucleus, and therefore it may play a role in the generation of hippocampal theta. In the present study, extracellular activity from VTn neurons were recorded in unanesthetized restrained rats (n = 9). Hippocampal activity (EEG) and electromyograms were recorded simultaneously to identify sleep-waking states. RB activity was observed in VTn during wakefulness, with periods of hippocampal theta and during rapid eye movement (REM) sleep. Rhythmicity in VTn preceded theta activity in hippocampus. The frequency of RB neurons in VTn was 5.6 Hz during wakefulness and 6.8 Hz during REM sleep. It was similar to that of hippocampal theta. The rhythmicity was particularly stable and the firing rates were strikingly high during REM sleep. RB activity in VTn was also recorded from urethane-anesthetized rates (n = 3). Rhythmic firing (4.0 Hz) was slower than in unanesthetized rats and matched the urethane-related theta frequency. Our results show that neurons in VTn exhibit a marked RB activity during states of vigilance accompanied by hippocampal theta rhythm. They suggest that VTn may be a pontine hippocampal theta generator.
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Affiliation(s)
- M H Bassant
- Neurobiologie de la Croissance et de la Sénescence, INSERM U 549, Paris, France.
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30
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Vanderwolf CH. The hippocampus as an olfacto-motor mechanism: were the classical anatomists right after all? Behav Brain Res 2001; 127:25-47. [PMID: 11718883 DOI: 10.1016/s0166-4328(01)00354-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The relations between behavior, olfactory input (monitored by recording the activity of the olfactory mucosa), and the spontaneous field potentials of the dentate gyrus were studied in freely moving rats. Bursts of 30-80 Hz (gamma) waves were elicited in the dentate gyrus when a rat sniffed at a variety of objects but were not elicited by auditory, somesthetic, or visual inputs and were not related to the occurrence of locomotion. The presence of gamma wave activity was associated with an enhancement of the population spike elicited in the dentate gyrus by stimulation of the perforant path. Odorized air blown into a nostril via a cannula, inserted under light urethane anesthesia, elicited a gamma wave response bilaterally in the dentate gyrus. These and other data were reviewed to support the general hypothesis that the hippocampus is primarily an olfacto-motor mechanism and does not play any unique role in learning and memory, cognitive mapping, or emotion. The role of the hippocampus in the control of some forms of motor activity is supported by numerous anatomical and electrophysiological studies, studies of the effect of hippocampal lesions on behavior, and studies of the effects of electrical or chemical stimulation of the hippocampus on behavior.
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Affiliation(s)
- C H Vanderwolf
- Graduate Program in Neuroscience, Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2
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31
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Abstract
The dorsal premammillary nucleus (PMd) is thought to play a critical role for the expression of fear responses to environmental threats. We have reported previously that during an encounter with a predator the PMd presents an impressive increase in Fos levels and cell body-specific chemical lesions therein virtually eliminate the expression of escape and freezing responses. In the present study, we carried out a systematic analysis of PMd afferent connections combining anterograde and retrograde tracing methods in the rat. We show that the nucleus receives inputs from several widely distributed areas in the forebrain and, to a much lesser extent, from the brainstem as well. From this information, it seems that the major telencephalic source of input to the PMd is the interfascicular nucleus of the bed nuclei of the stria terminalis. In addition, substantial telencephalic inputs to the nucleus seem to arise from the infralimbic and prelimbic areas, and the lateral septal nucleus. In the diencephalon, massive inputs to the PMd arise from the anterior hypothalamic nucleus, specific parts of the perifornical region, the retinoceptive region of the lateral hypothalamic area, and the anterior and dorsomedial parts of the ventromedial hypothalamic nucleus. In contrast, the ventral tegmental nucleus seems to be the only brainstem site that provides substantial inputs to the PMd. Overall, the present analysis helps to delineate prosencephalic circuits seemingly critical for the organization of innate fear responses to environmental threats, where the PMd presents a major associative role. Furthermore, by means of massive inputs from the ventral tegmental nucleus, the PMd is in a position to integrate information from a neural system involved in spatial working memory, which may be of particular relevance for an effect of attentional mechanisms on the selection of appropriate escape strategies.
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Affiliation(s)
- E Comoli
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Såo Paulo, Såo Paulo, CEP 05508-900, Brazil
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Liu H, Mihailoff GA. Hypothalamopontine projections in the rat: anterograde axonal transport studies utilizing light and electron microscopy. THE ANATOMICAL RECORD 1999; 255:428-51. [PMID: 10409816 DOI: 10.1002/(sici)1097-0185(19990801)255:4<428::aid-ar9>3.0.co;2-s] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Projections to the basilar pontine nuclei (BPN) from a variety of hypothalamic nuclei were traced in the rat utilizing the anterograde transport of biotinylated dextran amine. Light microscopy revealed that the lateral hypothalamic area (LH), the posterior hypothalamic area (PH), and the medial and lateral mammillary nuclei (MMN and LMN) are the four major hypothalamic nuclei that give rise to labeled fibers and terminals reaching the rostral medial and dorsomedial BPN subdivisions. Hypothalamopontine fibers extended caudally through the pontine tegmentum dorsal to the nucleus reticularis tegmenti pontis and then coursed ventrally from the main descending bundle toward the ipsilateral basilar pontine gray. Some hypothalamopontine fibers crossed the midline in the tegmental area just dorsal to the pontine gray to terminate in the contralateral BPN. Electron microscopy revealed that the ultrastructural features of synaptic boutons formed by axons arising in the LH, PH, MMN, and LMN are similar to one another. All labeled hypothalamopontine axon terminals contained round synaptic vesicles and formed asymmetric synaptic junctions with dendritic shafts as well as dendritic appendages, and occasionally with neuronal somata. Some labeled boutons formed the central axon terminal in a glomerular synaptic complex. In summary, the present findings indicate that the hypothalamus projects predominantly to the rostral medial and dorsomedial portions of the BPN which, in turn, provide input to the paraflocculus and vermis of the cerebellum. Since the hypothalamic projection zones in the BPN also receive cerebral cortical input, including limbic-related cortex, the hypothalamopontine system might serve to integrate autonomic or limbic-related functions with movement or somatic motor-related activity. Alternatively, since the cerebellum also receives direct input from the hypothalamus, the BPN may function to provide additional somatic and visceral inputs that are used by the cerebellum to perform the integrative function.
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Affiliation(s)
- H Liu
- Department of Anatomy, University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA
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33
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Gonzalo-Ruiz A, Romero JC, Sanz JM, Morte L. Localization of amino acids, neuropeptides and cholinergic neurotransmitter markers in identified projections from the mesencephalic tegmentum to the mammillary nuclei of the rat. J Chem Neuroanat 1999; 16:117-33. [PMID: 10223311 DOI: 10.1016/s0891-0618(98)00063-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Retrograde labelling has been combined with immunohistochemistry to localize neurons containing GABA, glutamate, choline acetyltransferase, leu-enkephalin, neurotensin and substance P-like immunoreactivity in the projection pathways from the midbrain tegmental nuclei to the mammillary nuclei in the rat. Injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the medial mammillary nucleus resulted in retrogradely labelled neurons in the ventral tegmental nucleus of Gudden, whereas injections into the lateral mammillary nucleus resulted in large numbers of retrogradely labelled neurons in the ipsilateral dorsal tegmental nucleus of Gudden and in the laterodorsal tegmental nucleus. In the ventral tegmental nucleus, moderate to small numbers of retrogradely labelled neurons were also immunolabelled for GABA and approximately ten to 18 WGA-HRP-labelled neurons per section were immunoreactive for leu-enkephalin. In addition, small numbers of WGA-HRP-labelled neurons in the principal subnucleus of the ventral tegmental nucleus were immunoreactive for Glu whereas small numbers of retrogradely labelled neurons in the compact subnucleus of the central superior nucleus displayed neurotensin-like immunoreactivity. In the ventral subnucleus of the dorsal tegmental nucleus, moderate to small numbers of retrogradely labelled neurons were also GABA-immunoreactive and approximately ten to 14 WGA-HRP labelled neurons per section were immunoreactive for leu-enkephalin. The ventral subnucleus of the dorsal tegmental nucleus also contained small numbers of retrogradely labelled neurons that displayed either glutamate or substance P-like immunoreactivity. In addition, moderate to small numbers of WGA-HRP-labelled neurons (five to 20 per section) in the laterodorsal tegmental nucleus were immunoreactive for choline acetyltransferase. These results are compatible with the possibility that tegmentomammillary projection neurons use several different neurochemicals as neurotransmitter(s) and/or neuromodulator(s).
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Affiliation(s)
- A Gonzalo-Ruiz
- Department of Anatomy, School of Physiotherapy, Valladolid University, Soria, Spain
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34
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Gonzalo-Ruiz A, Morte L, Sanz JM. Glutamate/aspartate and leu-enkephalin immunoreactivity in mammillothalamic projection neurons of the rat. Brain Res Bull 1998; 47:565-74. [PMID: 10078614 DOI: 10.1016/s0361-9230(98)00077-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have used retrograde transport and immunohistochemistry to study glutamate, aspartate, and enkephalin-like immunoreactive pathways from the mammillary nuclei to the anterior nuclei of the thalamus. Injections of wheat germ agglutinin conjugated to horseradish peroxidase into the anterodorsal thalamic nucleus resulted in retrogradely labelled cell bodies in the lateral mammillary nucleus, bilaterally, whereas injections into the anteroventral thalamic nucleus resulted in retrogradely labelled neurons in the ipsilateral medial mammillary nucleus. In three parallel series of sections immunoreacted for glutamate, aspartate, and enkephalin, respectively, 50-60% of the retrogradely labelled cell bodies were also immunolabelled for glutamate, 50-60% for aspartate, and 40-50% for enkephalin. The enkephalin-immunoreactive neurons may coincide with or constitute a separate population from the glutamate/aspartate-containing neurons. These results are compatible with the possibility that mammillothalamic projection neurons may use glutamate and/or aspartate and enkephalin as neurotransmitters.
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Affiliation(s)
- A Gonzalo-Ruiz
- Department of Anatomy, School of Physiotherapy, Valladolid University, Soria, Spain
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35
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Blair HT, Cho J, Sharp PE. Role of the lateral mammillary nucleus in the rat head direction circuit: a combined single unit recording and lesion study. Neuron 1998; 21:1387-97. [PMID: 9883731 DOI: 10.1016/s0896-6273(00)80657-1] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We recorded head direction (HD) cells from the lateral mammillary nucleus (LMN) and anterior thalamus (ATN) of freely behaving rats and also made bilateral lesions of LMN while recording HD cells from ATN. We discovered that the tuning functions of LMN HD cells become narrower during contraversive head turns, but not ipsiversive head turns, compared to when the head is not turning. This narrowing effect does not occur for ATN HD cells. We also found that the HD signal in LMN leads that in ATN by about 15-20 ms. When LMN was lesioned bilaterally, HD cells in ATN immediately lost their directional firing properties and never recovered them. Based on these findings, we argue that LMN may be an essential component of an attractor-integrator network that participates in generating the HD signal.
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Affiliation(s)
- H T Blair
- Department of Psychology, Yale University, New Haven, Connecticut 06520, USA.
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36
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Allen GV, Hopkins DA. Convergent prefrontal cortex and mamillary body projections to the medial pontine nuclei: a light and electron microscopic study in the rat. J Comp Neurol 1998; 398:347-58. [PMID: 9714148 DOI: 10.1002/(sici)1096-9861(19980831)398:3<347::aid-cne4>3.0.co;2-#] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To study the convergence of medial prefrontal cortex and mamillary body projections to the medial pontine nuclei, light and electron microscopic, neuroanatomical, tract-tracing experiments were performed. Injections of horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP), biotin conjugated to dextran (BD), or rhodamine conjugated to dextran (RD) were made individually or in combinations into the cerebral cortex, hypothalamus, or pons. In addition, injections of WGA-HRP into the medial prefrontal cortex and electrolytic lesions of the mamillary body were made to study the synaptology of afferent projections to the pontine nuclei. In the light microscopic studies, injections of WGA-HRP into the rostromedial pontine nuclei produced dense, retrograde labeling both in the dorsal peduncular area of the medial prefrontal cortex and in the medial mamillary nucleus, pars medialis. Injections of the anterograde tracers BD and RD into the medial prefrontal cortex and the medial mamillary nuclei, respectively, resulted in partially overlapping terminal fields in the rostromedial pontine nuclei. In the electron microscopic studies, injections of WGA-HRP into the dorsal peduncular area and electrolytic lesions of the mamillary body produced anterogradely labeled axon terminals and degenerating axon terminals that synapsed on the same dendrites or neuronal somata in the rostromedial pontine nuclei. The results demonstrate that the medial prefrontal cortex and the medial mamillary nuclei have partially overlapping projections to the rostromedial pontine nuclei and implicate precerebellar relay nuclei in the integration of limbic and/or autonomic functions mediated by convergent projections from the cerebral cortex and the hypothalamus.
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Affiliation(s)
- G V Allen
- Department of Anatomy and Neurobiology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
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37
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Ochiishi T, Yamauchi T, Terashima T. Regional differences between the immunohistochemical distribution of Ca2+/calmodulin-dependent protein kinase II alpha and beta isoforms in the brainstem of the rat. Brain Res 1998; 790:129-40. [PMID: 9593859 DOI: 10.1016/s0006-8993(98)00058-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The distribution of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) alpha and beta isoforms in the brainstem of adult rats was investigated using an immunohistochemical method with two monoclonal antibodies which specifically recognize the alpha and beta isoform, respectively. We found that these isoforms were differentially expressed by neurons in the substantia nigra, red nucleus, dorsal cochlear nucleus, pontine nuclei and inferior olivary nucleus. Neurons in the inferior olivary nucleus express the alpha isoform, but not the beta isoform. In contrast, neurons in the substantia nigra, red nucleus and pontine nuclei were immunostained with the beta antibody, but not with the alpha antibody. In the dorsal cochlear nucleus, neurons in layers I and II were alpha-immunopositive, whereas neurons in layers III and IV were beta-immunopositive. Therefore, the distribution of the CaM kinase II alpha-immunopositive neurons is completely different from that of CaM kinase II beta-immunopositive neurons. Next we examined the possible coexistence of CaM kinase II alpha isoform and glutamate or that of CaM kinase II beta isoform and glutamic acid decarboxylase (GAD) in the single neuron by double immunofluorescence labelling using a pair of anti-alpha and anti-glutamate antibodies, or a pair of anti-beta and anti-GAD antibodies. The results indicated that neurons expressing anti-alpha immunoreactivity were also immunopositive against anti-glutamate antibody, and neurons expressing beta isoform were also immunopositive against anti-GAD antibody, suggesting that alpha-immunopositive neurons are classified as excitatory-type neurons, and on the contrary, beta-immunopositive neurons are classified as inhibitory-type neurons. In conclusion, the present study confirmed that alpha- and beta-isoforms of CaM kinase II are differentially expressed in the nuclei of the brainstem and have different roles.
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Affiliation(s)
- T Ochiishi
- Biosignalling Department, National Institute of Bioscience and Human-Technology, Agency of Industrial Science and Technology, M.I.T. I., Tsukuba, Ibaraki 305-8566, Japan.
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Haines DE, Dietrichs E, Mihailoff GA, McDonald EF. The cerebellar-hypothalamic axis: basic circuits and clinical observations. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1997; 41:83-107. [PMID: 9378614 DOI: 10.1016/s0074-7742(08)60348-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Experimental studies on a variety of mammals, including primates, have revealed direct and reciprocal connections between the hypothalamus and the cerebellum. Although widespread areas of the hypothalamus project to cerebellum, axons arise primarily from cells in the lateral, posterior, and dorsal hypothalamic areas; the supramammillary, tuberomammillary, and lateral mammillary nuclei; the dorsomedial and ventromedial nuclei; and the periventricular zone. Available evidence suggests that hypothalamocerebellar cortical fibers may terminate in relation to neurons in all layers of the cerebellar cortex. Cerebellohypothalamic axons arise from neurons of all four cerebellar nuclei, pass through the superior cerebellar peduncle, cross in its decussation, and enter the hypothalamus. Some axons recross the midline in caudal areas of the hypothalamus. These fibers terminate primarily in lateral, posterior, and dorsal hypothalamic areas and in the dorsomedial and paraventricular nuclei. Evidence of a cerebellar influence on the visceromotor system is presented in two patients with vascular lesions: one with a small defect in the medial cerebellar nucleus and the other with a larger area of damage involving primarily the globose and emboliform nuclei. Both patients exhibited an abnormal visceromotor response. The second, especially, showed abnormal visceromotor activity concurrent with tremor induced by voluntary movement. These experimental and clinical data suggest that the cerebellum is actively involved in the regulation of visceromotor functions.
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Affiliation(s)
- D E Haines
- Department of Anatomy, University of Mississippi Medical Center, Jackson 39216, USA
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39
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Risold PY, Thompson RH, Swanson LW. The structural organization of connections between hypothalamus and cerebral cortex. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1997; 24:197-254. [PMID: 9385455 DOI: 10.1016/s0165-0173(97)00007-6] [Citation(s) in RCA: 242] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Motivated behavior requires coordinated somatic, autonomic, and endocrine responses, and may be divided into initiation, procurement, and consummatory phases (Swanson, L.W. and Mogenson, G.J., Neural mechanisms for the functional coupling of autonomic, endocrine and somatomotor responses in adaptative behavior, Brain Res. Rev., 3 (1981) 1-34). Obviously, such behavior may involve the entire central nervous system, although it is important to identify circuitry or systems that mediate the behavior directed toward specific goal objects. This problem has recently been clarified by the identification of hypothalamic subsystems important for the execution of instinctive behaviors related to ingestion, reproduction, and defense. These subsystems are modulated by sensory (reflex), central control (e.g., circadian), and voluntary (cortical) inputs. The latter are dominated by inputs from the ventral temporal lobe and medial prefrontal region, which are both direct and via associated parts of the basal nuclei (ganglia). Hypothalamic output is characterized by descending projections to brainstem and spinal motor systems, and by projections back to the cerebral cortex, which are both direct and via a continuous rostromedial part of the dorsal thalamus. This thalamic region includes the anterior, medial, and midline groups, which in turn innervate a continuous ring of cortex that includes the hippocampal formation and the cingulate, prefrontal, and insular regions. Parts of this thalamic region also innervate the ventral striatum, which receives a massive input from the cortical rings as well.
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Affiliation(s)
- P Y Risold
- Program for Neural, Informational and Behavioral Sciences, University of Southern California, Los Angeles 90089-2520, USA
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40
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Shim I, Wirtshafter D. Fos-like immunoreactivity in the mamillary body and thalamus following injections of muscimol into the ventral tegmental nucleus of Gudden in the rat. Brain Res 1996; 712:173-8. [PMID: 8814891 DOI: 10.1016/0006-8993(95)01301-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In many neurons, increased rates of firing are accompanied by expression of the proto-oncoprotein Fos. The current study examined Fos-like immunoreactivity in the mamillary body and the anterior thalamus following unilateral injections of the inhibitory GABA-A agonist muscimol into the ventral tegmental nucleus of Gudden (VTN). These injections resulted in a marked increase in Fos-like immunoreactivity ipsilaterally in both the medial mamillary nucleus and in its principle thalamic projection targets, the anteroventral and anteromedial thalamic nuclei. Since the projection from the VTN to the mamillary body has been shown to contain a substantial GABAergic component, these results are likely to reflect a disinhibition of mamillothalamic circuitry resulting from suppression of tonic inhibitory inputs arising in the VTN.
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Affiliation(s)
- I Shim
- Department of Psychology, University of Illinois at Chicago 60607-7137, USA
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41
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van Lookeren Campagne M, Lucassen PJ, Vermeulen JP, Balázs R. NMDA and kainate induce internucleosomal DNA cleavage associated with both apoptotic and necrotic cell death in the neonatal rat brain. Eur J Neurosci 1995; 7:1627-40. [PMID: 7551189 DOI: 10.1111/j.1460-9568.1995.tb01158.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Injection of N-methyl-D-aspartate (NMDA) or kainate in the striatum of 7-day-old rats induced massive cell loss in the ipsilateral striatum, hippocampus and inner cortical layers. In order to examine whether apoptosis contributes to cell death in this model of excitotoxic injury we examined the progression of internucleosomal DNA fragmentation and changes in cellular ultrastructure. Agarose gel electrophoresis of DNA extracted from the ipsilateral striatum, cerebral cortex and hippocampus clearly showed breakdown of DNA into oligonucleosome-sized fragments, indicative of apoptosis, 12 h post-NMDA injection. In addition, an increase between 12 and 24 h was observed as well as a continuous presence 5 days later. Kainate induced a similar time course of oligonucleosomal DNA fragmentation, but the intensity of the ethidium bromide stained bands was less compared with that observed for NMDA. DNA fragmentation was not detected in animals intrastriatally injected with Tris-HCl or in animals treated with MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohept-5,10-imine hydrogen maleate, 1 mg/kg] 30 min after NMDA injection. MK-801 had no effect on DNA fragmentation induced by kainate. In addition to agarose gel electrophoresis, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labelling (TUNEL) was used for detection of DNA fragmentation in sections. A gradual increase in the density of both apoptotic and non-apoptotic TUNEL nuclei was found in the anterior cingulate (ACC) and retrosplenial (RSC) areas of the cortex, the striatum, and the CA1 area and dentate gyrus of the hippocampus over the first 24 h post-NMDA or kainate injection. In the contralateral hemisphere hardly any TUNEL nuclei were present and their density was comparable with that in animals injected with vehicle only. In the ipsilateral mammillary nucleus (MN), which showed no signs of acute cell swelling after intrastriatal injection with NMDA, internucleosomal DNA fragmentation was found 24 and 48 h after intrastriatal NMDA injection. Here, the density of TUNEL cells with apoptotic morphology was high at 12 and 24 h post-NMDA injection but returned to control levels by 5 days. Electron microscopy showed cells with a clearly apoptotic morphology in the ACC and RSC and in the MN 24 h after NMDA injection. In the CA1 area of the hippocampus a necrotic, rather than an apoptotic, ultrastructure prevailed, indicating that the TUNEL method stained both apoptotic and necrotic cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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Allen GV, Cechetto DF. Functional and anatomical organization of cardiovascular pressor and depressor sites in the lateral hypothalamic area. II. Ascending projections. J Comp Neurol 1993; 330:421-38. [PMID: 7682225 DOI: 10.1002/cne.903300310] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Microinjections of L-glutamate or D,L-homocysteic acid were used to stimulate cell bodies in the region of the lateral hypothalamic area (LHA) selectively. Subsequent iontophoretic injections of Phaseolus vulgaris-leucoagglutinin or pressure injections of wheat germ agglutinin-horseradish peroxidase were made into regions containing identified pressor and depressor sites and their connections with the forebrain and cerebral cortex were traced. The results indicate that decreases in blood pressure (10-45 mm Hg) and heart rate (20-70 bpm) could be elicited from tuberal (LHAt) and posterior (LHAp) sites in the LHA and that these regions have ascending projections to the insular cortex, the ventral forebrain including the septal-diagonal band of Broca complex, the ventral palladium, substantia innominata, amygdala, and the lateral preoptic area. In contrast, increases in blood pressure (10-40 mm Hg) and heart rate (20-70 bpm) were elicited primarily from neurons located adjacent to the fornix in the perifornical area (PFA). Injections of tract tracers into this region produced terminal labeling that differed markedly from the pattern seen following injections of tracer into depressor sites in the LHA. In addition, the pattern of anterograde labeling seen following injections of tracer into the anterior PFA differed from that seen following injections of tracer into the posterior PFA. Injections of tracer into the anterior PFA resulted in dense terminal labeling in the medial preoptic area and the parvicellular paraventricular nucleus of the hypothalamus whereas injections into the posterior PFA resulted in dense terminal labeling in the lateral septal nucleus, nucleus accumbens, bed nucleus of the stria terminalis, as well as the medial preoptic area and the parvocellular paraventricular nucleus of the hypothalamus. The results demonstrate that the posterolateral hypothalamus of the rat contains two regions with specific cardiovascular function and highly organized connections with diencephalic, forebrain, and cortical structures.
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Affiliation(s)
- G V Allen
- Robarts Research Institute, London, Ontario, Canada
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43
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Abstract
Cannabinoid receptor mRNA was localized in adult rat brain by 35S-tailed oligonucleotide probes and in situ hybridization histochemistry. Labelling is described as uniform or non-uniform depending on the relative intensities of individual cells expressing cannabinoid receptor mRNA within a given region or nucleus. Uniform labelling was found in the hypothalamus, thalamus, basal ganglia, cerebellum and brainstem. Non-uniform labelling that resulted from the presence of cells displaying two easily distinguishable intensities of hybridization signals was observed in several regions and nuclei in the forebrain (cerebral cortex, hippocampus, amygdala, certain olfactory structures). Olfactory-associated structures, basal ganglia, hippocampus, and cerebellar cortex displayed the heaviest amounts of labelling. Many regions that displayed cannabinoid receptor mRNA could reasonably be identified as sources for cannabinoid receptors on the basis of well documented hodologic data. Other sites that were also clearly labelled could not be assigned as logical sources of cannabinoid receptors. The localization of cannabinoid receptor mRNA indicates that sensory, motor, cognitive, limbic, and autonomic systems should all be influenced by the activation of this receptor by either exogenous cannabimimetics, including marijuana, or the yet unknown endogenous "cannabinoid" ligand.
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Affiliation(s)
- L A Matsuda
- Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, Maryland 20892
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44
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Shibata H. Topographic organization of subcortical projections to the anterior thalamic nuclei in the rat. J Comp Neurol 1992; 323:117-27. [PMID: 1385491 DOI: 10.1002/cne.903230110] [Citation(s) in RCA: 125] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Subcortical projections to the anterior thalamic nuclei were studied in the rat, with special reference to projections from the mammillary nuclei, by retrograde and anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase. The medial mammillary nucleus (MM) projects predominantly ipsilaterally to the entire anterior thalamic nuclei, whereas the lateral mammillary nucleus projects bilaterally to the anterodorsal nucleus (AD) of the anterior thalamic nuclei. A topographic relationship was recognized between the MM and the anterior thalamic nuclei. The dorsal region of the pars mediana of the MM projects to the interanteromedial nucleus (IAM), whereas the ventral region projects to the rostral part of the anteromedial nucleus (AM). The dorsal and the ventral regions of the pars medialis project to the dorsomedial part of the AM at its caudal and rostral levels, respectively. The dorsomedial region of the pars lateralis projects to the ventral AM. The ventrolateral region of the pars lateralis projects to the ventral part of the anteroventral nucleus (AV) in such a manner that rostral cells project rostrally and caudal cells project caudally. The pars basalis projects predominantly ipsilaterally to the dorsolateral AV and bilaterally to the AD. The rostrolateral region of the pars posterior projects to the lateral AV, whereas the medial and the caudal regions of the pars posterior project to the dorsomedial AV. The rostrodorsal part of the nucleus reticularis thalami was found to project to the anterior thalamic nuclei; cells located rostrally in this part project to the IAM and AM, whereas cells located caudodorsally project to the AV and AD. The laterodorsal tegmental nucleus projects predominantly ipsilaterally to the AV, especially to its dorsolateral part. The present study demonstrates that subdivisions of the subcortical structures are connected to the subnuclei of the anterior thalamic nuclei, with a clear-cut topography arranged in the dorsoventral and the rostrocaudal dimensions.
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Affiliation(s)
- H Shibata
- Department of Veterinary Anatomy, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan
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45
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Huang XF, Törk I, Halliday GM, Paxinos G. The dorsal, posterodorsal, and ventral tegmental nuclei: a cyto- and chemoarchitectonic study in the human. J Comp Neurol 1992; 318:117-37. [PMID: 1374765 DOI: 10.1002/cne.903180202] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In order to verify the existence of the ventral and posterodorsal tegmental nuclei and to extend previous findings regarding the dorsal tegmental nucleus in the human brainstem, studies were conducted using cyto- and chemoarchitectonics, and computer reconstruction techniques. Serial sections of five brainstems from adults with no known neurological disorders were stained for Nissl substance, acetylcholinesterase, and substance P. The topography, cytoarchitecture, and acetylcholinesterase reactivity of the tegmental nuclei were presented in a mini-atlas depicting sections cut in transverse and sagittal planes. The dorsal and posterodorsal tegmental nuclei were identified fully within the central grey matter while the ventral tegmental nucleus extended across the medial longitudinal fasciculus into the pontine reticular formation. The dorsal tegmental nucleus featured a cell-poor pericentral part, strongly positive for acetylcholinesterase, and a central part comprised of densely packed small neurons that displayed moderate acetylcholinesterase reactivity and strong substance P-like immunoreactivity. The posterodorsal tegmental nucleus, located in the same transverse plane as the rostral part of the motor nucleus of the trigeminal nerve, was composed of diffusely arranged small to medium neurons with its neuropil displaying moderate acetylcholinesterase reactivity and strong substance P-like immunoreactivity. The ventral tegmental nucleus, identified as a prominent structure in the pontine tegmentum immediately rostral to the genu of the facial nerve, contained predominantly large neurons and displayed intensive acetylcholinesterase reactivity and substance P-like immunoreactivity. These studies showed that the tegmental nuclei, which displayed distinctive cyto- and chemoarchitectonic features, were fully present in adult human brainstem.
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Affiliation(s)
- X F Huang
- School of Anatomy, University of New South Wales, Kensington, Australia
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Hayakawa T, Zyo K. Quantitative and ultrastructural study of ascending projections to the medial mammillary nucleus in the rat. ANATOMY AND EMBRYOLOGY 1991; 184:611-22. [PMID: 1776707 DOI: 10.1007/bf00942583] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We analyzed the termination pattern of axons from the superior central nucleus and the ventral tegmental nucleus of Gudden within the medial mammillary nucleus (MM) in the rat. The neuropil of the MM consists of two classes of terminals, that is, terminals containing round synaptic vesicles and forming asymmetric synaptic contact, and terminals containing pleomorphic synaptic vesicles and forming symmetric synaptic contact. The number of axodendritic terminals with round vesicles is almost equal to that of terminals with pleomorphic vesicles. Almost all axosomatic terminals contain pleomorphic vesicles with symmetric synaptic contact. Injection of WGA-HRP into the central part of the superior central nucleus permitted ultrastructural recognition of many anterogradely labeled terminals within the median region of MM. The labeled terminals contacted mainly intermediate (1-2 microns diameter) and proximal dendrites (more than 2 microns diameter) as well as the neuronal somata. Serial ultrathin sections of neurons of the median region of the MM revealed that 37% of the axosomatic terminals were labeled anterogradely. The pars compacta of the superior central nucleus had reciprocal connections with the median region of MM. The axon terminals from this nucleus occupied 53% of axosomatic terminals, and contacted mainly intermediate dendrites. Following injection of WGA-HRP into the ventral tegmental nucleus, many labeled terminals were found in the medial and lateral regions of MM. They contacted mainly intermediate dendrites as well as neuronal somata. In the medial region, 78% of axosomatic terminals contacting retrogradely labeled neurons were labeled anterogradely. All labeled terminals from these nuclei contained pleomorphic vesicles, and made symmetric synaptic contact.
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Affiliation(s)
- T Hayakawa
- Department of Anatomy, Hyogo College of Medicine, Japan
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