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Nitzan N, Buzsáki G. Physiological characteristics of neurons in the mammillary bodies align with topographical organization of subicular inputs. Cell Rep 2024; 43:114539. [PMID: 39052483 DOI: 10.1016/j.celrep.2024.114539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/20/2024] [Accepted: 07/09/2024] [Indexed: 07/27/2024] Open
Abstract
The mammillary bodies (MBOs), a group of hypothalamic nuclei, play a pivotal role in memory formation and spatial navigation. They receive extensive inputs from the hippocampus through the fornix, but the physiological significance of these connections remains poorly understood. Damage to the MBOs is associated with various forms of anterograde amnesia. However, information about the physiological characteristics of the MBO is limited, primarily due to the limited number of studies that have directly monitored MBO activity along with population patterns of its upstream partners. Employing large-scale silicon probe recording in mice, we characterize MBO activity and its interaction with the subiculum across various brain states. We find that MBO cells are highly diverse in their relationship to theta, ripple, and slow oscillations. Several of the physiological features are inherited by the topographically organized inputs to MBO cells. Our study provides insights into the functional organization of the MBOs.
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Affiliation(s)
- Noam Nitzan
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10016, USA
| | - György Buzsáki
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10016, USA.
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2
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Sharma R, Kumarasamy M, Parihar VK, Ravichandiran V, Kumar N. Monoamine Oxidase: A Potential Link in Papez Circuit to Generalized Anxiety Disorders. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:638-655. [PMID: 37055898 DOI: 10.2174/1871527322666230412105711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 04/15/2023]
Abstract
Anxiety is a common mental illness that affects a large number of people around the world, and its treatment is often based on the use of pharmacological substances such as benzodiazepines, serotonin, and 5-hydroxytyrosine (MAO) neurotransmitters. MAO neurotransmitters levels are deciding factors in the biological effects. This review summarizes the current understanding of the MAO system and its role in the modulation of anxiety-related brain circuits and behavior. The MAO-A polymorphisms have been implicated in the susceptibility to generalized anxiety disorder (GAD) in several investigations. The 5-HT system is involved in a wide range of physiological and behavioral processes, involving anxiety, aggressiveness, stress reactions, and other elements of emotional intensity. Among these, 5-HT, NA, and DA are the traditional 5-HT neurons that govern a range of biological activities, including sleep, alertness, eating, thermoregulation, pains, emotion, and memory, as anticipated considering their broad projection distribution in distinct brain locations. The DNMTs (DNA methyltransferase) protein family, which increasingly leads a prominent role in epigenetics, is connected with lower transcriptional activity and activates DNA methylation. In this paper, we provide an overview of the current state of the art in the elucidation of the brain's complex functions in the regulation of anxiety.
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Affiliation(s)
- Ravikant Sharma
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali- 844102, Bihar, India
| | - Murali Kumarasamy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali- 844102, Bihar, India
| | - Vipan Kumar Parihar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali-844102, Bihar, India
| | - V Ravichandiran
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali- 844102, Bihar, India
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali-844102, Bihar, India
| | - Nitesh Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Hajipur, Vaishali-844102, Bihar, India
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3
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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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4
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Aggleton JP, Nelson AJD, O'Mara SM. Time to retire the serial Papez circuit: Implications for space, memory, and attention. Neurosci Biobehav Rev 2022; 140:104813. [PMID: 35940310 PMCID: PMC10804970 DOI: 10.1016/j.neubiorev.2022.104813] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/20/2022] [Accepted: 08/01/2022] [Indexed: 11/26/2022]
Abstract
After more than 80 years, Papez serial circuit remains a hugely influential concept, initially for emotion, but in more recent decades, for memory. Here, we show how this circuit is anatomically and mechanistically naïve as well as outdated. We argue that a new conceptualisation is necessitated by recent anatomical and functional findings that emphasize the more equal, working partnerships between the anterior thalamic nuclei and the hippocampal formation, along with their neocortical interactions in supporting, episodic memory. Furthermore, despite the importance of the anterior thalamic for mnemonic processing, there is growing evidence that these nuclei support multiple aspects of cognition, only some of which are directly associated with hippocampal function. By viewing the anterior thalamic nuclei as a multifunctional hub, a clearer picture emerges of extra-hippocampal regions supporting memory. The reformulation presented here underlines the need to retire Papez serially processing circuit.
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Affiliation(s)
- John P Aggleton
- School of Psychology, Cardiff University, 70 Park Place, Cardiff CF10 3AT, Wales, UK.
| | - Andrew J D Nelson
- School of Psychology, Cardiff University, 70 Park Place, Cardiff CF10 3AT, Wales, UK
| | - Shane M O'Mara
- School of Psychology and Trinity College Institute of Neuroscience, Trinity College Dublin, The University of Dublin, Dublin D02 PN40, Ireland
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5
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Meys KME, de Vries LS, Groenendaal F, Vann SD, Lequin MH. The Mammillary Bodies: A Review of Causes of Injury in Infants and Children. AJNR Am J Neuroradiol 2022; 43:802-812. [PMID: 35487586 PMCID: PMC9172959 DOI: 10.3174/ajnr.a7463] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/22/2021] [Indexed: 12/20/2022]
Abstract
Despite their small size, the mammillary bodies play an important role in supporting recollective memory. However, they have typically been overlooked when assessing neurologic conditions that present with memory impairment. While there is increasing evidence of mammillary body involvement in a wide range of neurologic disorders in adults, very little attention has been given to infants and children. Literature searches of PubMed and EMBASE were performed to identify articles that describe mammillary body pathology on brain MR imaging in children. Mammillary body pathology is present in the pediatric population in several conditions, indicated by signal change and/or atrophy on MR imaging. The main causes of mammillary body pathology are thiamine deficiency, hypoxia-ischemia, direct damage due to masses or hydrocephalus, or deafferentation resulting from pathology within the wider Papez circuit. Optimizing scanning protocols and assessing mammillary body status as a standard procedure are critical, given their role in memory processes.
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Affiliation(s)
- K M E Meys
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - L S de Vries
- Department of Neonatology (L.S.D.V.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - F Groenendaal
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - S D Vann
- School of Psychology (S.D.V.), Cardiff University, Cardiff, UK
| | - M H Lequin
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
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6
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Wirtshafter HS, Disterhoft JF. In Vivo Multi-Day Calcium Imaging of CA1 Hippocampus in Freely Moving Rats Reveals a High Preponderance of Place Cells with Consistent Place Fields. J Neurosci 2022; 42:4538-4554. [PMID: 35501152 PMCID: PMC9172072 DOI: 10.1523/jneurosci.1750-21.2022] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
Calcium imaging using GCaMP indicators and miniature microscopes has been used to image cellular populations during long timescales and in different task phases, as well as to determine neuronal circuit topology and organization. Because the hippocampus (HPC) is essential for tasks of memory, spatial navigation, and learning, calcium imaging of large populations of HPC neurons can provide new insight on cell changes over time during these tasks. All reported HPC in vivo calcium imaging experiments have been done in mouse. However, rats have many behavioral and physiological experimental advantages over mice. In this paper, we present the first (to our knowledge) in vivo calcium imaging from CA1 HPC in freely moving male rats. Using the UCLA Miniscope, we demonstrate that, in rat, hundreds of cells can be visualized and held across weeks. We show that calcium events in these cells are highly correlated with periods of movement, with few calcium events occurring during periods without movement. We additionally show that an extremely large percent of cells recorded during a navigational task are place cells (77.3 ± 5.0%, surpassing the percent seen during mouse calcium imaging), and that these cells enable accurate decoding of animal position and can be held over days with consistent place fields in a consistent spatial map. A detailed protocol is included, and implications of these advancements on in vivo imaging and place field literature are discussed.SIGNIFICANCE STATEMENT In vivo calcium imaging in freely moving animals allows the visualization of cellular activity across days. In this paper, we present the first in vivo Ca2+ recording from CA1 hippocampus (HPC) in freely moving rats. We demonstrate that hundreds of cells can be visualized and held across weeks, and that calcium activity corresponds to periods of movement. We show that a high percentage (77.3 ± 5.0%) of imaged cells are place cells, and that these place cells enable accurate decoding and can be held stably over days with little change in field location. Because the HPC is essential for many tasks involving memory, navigation, and learning, imaging of large populations of HPC neurons can shed new insight on cellular activity changes and organization.
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Affiliation(s)
- Hannah S Wirtshafter
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - John F Disterhoft
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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7
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McNaughton N, Vann SD. Construction of complex memories via parallel distributed cortical–subcortical iterative integration. Trends Neurosci 2022; 45:550-562. [PMID: 35599065 PMCID: PMC7612902 DOI: 10.1016/j.tins.2022.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/01/2022] [Accepted: 04/22/2022] [Indexed: 01/08/2023]
Abstract
The construction of complex engrams requires hippocampal-cortical interactions. These include both direct interactions and ones via often-overlooked subcortical loops. Here, we review the anatomical organization of a hierarchy of parallel ‘Papez’ loops through the hypothalamus that are homologous in mammals from rats to humans. These hypothalamic loops supplement direct hippocampal-cortical connections with iterative re-processing paced by theta rhythmicity. We couple existing anatomy and lesion data with theory to propose that recirculation in these loops progressively enhances desired connections, while reducing interference from competing external goals and internal associations. This increases the signal-to-noise ratio in the distributed engrams (neocortical and cerebellar) necessary for complex learning and memory. The hypothalamic nodes provide key motivational input for engram enhancement during consolidation.
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Affiliation(s)
- Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of Otago, POB56, Dunedin, New Zealand.
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Park Place, Cardiff, CF10 3AT, UK.
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8
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The anterior thalamic nuclei: core components of a tripartite episodic memory system. Nat Rev Neurosci 2022; 23:505-516. [PMID: 35478245 DOI: 10.1038/s41583-022-00591-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2022] [Indexed: 12/13/2022]
Abstract
Standard models of episodic memory focus on hippocampal-parahippocampal interactions, with the neocortex supplying sensory information and providing a final repository of mnemonic representations. However, recent advances have shown that other regions make distinct and equally critical contributions to memory. In particular, there is growing evidence that the anterior thalamic nuclei have a number of key cognitive functions that support episodic memory. In this article, we describe these findings and argue for a core, tripartite memory system, comprising a 'temporal lobe' stream (centred on the hippocampus) and a 'medial diencephalic' stream (centred on the anterior thalamic nuclei) that together act on shared cortical areas. We demonstrate how these distributed brain regions form complementary and necessary partnerships in episodic memory formation.
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9
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Küçükerden M, Schuster UE, Röckle I, Alvarez-Bolado G, Schwabe K, Hildebrandt H. Compromised mammillary body connectivity and psychotic symptoms in mice with di- and mesencephalic ablation of ST8SIA2. Transl Psychiatry 2022; 12:51. [PMID: 35115485 PMCID: PMC8814025 DOI: 10.1038/s41398-022-01816-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Altered long-range connectivity is a common finding across neurodevelopmental psychiatric disorders, but causes and consequences are not well understood. Genetic variation in ST8SIA2 has been associated with schizophrenia, autism, and bipolar disorder, and St8sia2-/- mice show a number of related neurodevelopmental and behavioral phenotypes. In the present study, we use conditional knockout (cKO) to dissect neurodevelopmental defects and behavioral consequences of St8sia2 deficiency in cortical interneurons, their cortical environment, or in the di- and mesencephalon. Neither separate nor combined cortical and diencephalic ablation of St8sia2 caused the disturbed thalamus-cortex connectivity observed in St8sia2-/- mice. However, cortical ablation reproduced hypoplasia of corpus callosum and fornix and mice with di- and mesencephalic ablation displayed smaller mammillary bodies with a prominent loss of parvalbumin-positive projection neurons and size reductions of the mammillothalamic tract. In addition, the mammillotegmental tract and the mammillary peduncle, forming the reciprocal connections between mammillary bodies and Gudden's tegmental nuclei, as well as the size of Gudden's ventral tegmental nucleus were affected. Only mice with these mammillary deficits displayed enhanced MK-801-induced locomotor activity, exacerbated impairment of prepulse inhibition in response to apomorphine, and hypoanxiety in the elevated plus maze. We therefore propose that compromised mammillary body connectivity, independent from hippocampal input, leads to these psychotic-like responses of St8sia2-deficient mice.
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Affiliation(s)
- Melike Küçükerden
- grid.10423.340000 0000 9529 9877Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany ,grid.412970.90000 0001 0126 6191Center for Systems Neuroscience Hannover (ZSN), Hannover, Germany
| | - Ute E. Schuster
- grid.10423.340000 0000 9529 9877Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Iris Röckle
- grid.10423.340000 0000 9529 9877Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Gonzalo Alvarez-Bolado
- grid.7700.00000 0001 2190 4373Institute for Anatomy and Cell Biology, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | - Kerstin Schwabe
- grid.412970.90000 0001 0126 6191Center for Systems Neuroscience Hannover (ZSN), Hannover, Germany ,grid.10423.340000 0000 9529 9877Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | - Herbert Hildebrandt
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany. .,Center for Systems Neuroscience Hannover (ZSN), Hannover, Germany.
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10
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Ge X, Zheng Y, Qiao Y, Pan N, Simon JP, Lee M, Jiang W, Kim H, Shi Y, Liu M. Hippocampal Asymmetry of Regional Development and Structural Covariance in Preterm Neonates. Cereb Cortex 2021; 32:4271-4283. [PMID: 34969086 DOI: 10.1093/cercor/bhab481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/21/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
Premature birth is associated with a high prevalence of neurodevelopmental impairments in surviving infants. The hippocampus is known to be critical for learning and memory, yet the putative effects of hippocampal dysfunction remain poorly understood in preterm neonates. In particular, while asymmetry of the hippocampus has been well noted both structurally and functionally, how preterm birth impairs hippocampal development and to what extent the hippocampus is asymmetrically impaired by preterm birth have not been well delineated. In this study, we compared volumetric growth and shape development in the hippocampal hemispheres and structural covariance (SC) between hippocampal vertices and cortical thickness in cerebral cortex regions between two groups. We found that premature infants had smaller volumes of the right hippocampi only. Lower thickness was observed in the hippocampal head in both hemispheres for preterm neonates compared with full-term peers, though preterm neonates exhibited an accelerated age-related change of hippocampal thickness in the left hippocampi. The SC between the left hippocampi and the limbic lobe of the premature infants was severely impaired compared with the term-born neonates. These findings suggested that the development of the hippocampus during the third trimester may be altered following early extrauterine exposure with a high degree of asymmetry.
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Affiliation(s)
- Xinting Ge
- School of Information Science and Engineering, Shandong Normal University, 250014 Jinan, China.,Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.,School of Medical Imaging, Xuzhou Medical University, 221004 Xuzhou, China
| | - Yuanjie Zheng
- School of Information Science and Engineering, Shandong Normal University, 250014 Jinan, China
| | - Yuchuan Qiao
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ningning Pan
- School of Information Science and Engineering, Shandong Normal University, 250014 Jinan, China
| | - Julia Pia Simon
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Mitchell Lee
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Wenjuan Jiang
- College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Hosung Kim
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Yonggang Shi
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Mengting Liu
- Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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11
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Dillingham CM, Milczarek MM, Perry JC, Vann SD. Time to put the mammillothalamic pathway into context. Neurosci Biobehav Rev 2021; 121:60-74. [PMID: 33309908 PMCID: PMC8137464 DOI: 10.1016/j.neubiorev.2020.11.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/10/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022]
Abstract
The medial diencephalon, in particular the mammillary bodies and anterior thalamic nuclei, has long been linked to memory and amnesia. The mammillary bodies provide a dense input into the anterior thalamic nuclei, via the mammillothalamic tract. In both animal models, and in patients, lesions of the mammillary bodies, mammillothalamic tract and anterior thalamic nuclei all produce severe impairments in temporal and contextual memory, yet it is uncertain why these regions are critical. Mounting evidence from electrophysiological and neural imaging studies suggests that mammillothalamic projections exercise considerable distal influence over thalamo-cortical and hippocampo-cortical interactions. Here, we outline how damage to the mammillary body-anterior thalamic axis, in both patients and animal models, disrupts behavioural performance on tasks that relate to contextual ("where") and temporal ("when") processing. Focusing on the medial mammillary nuclei as a possible 'theta-generator' (through their interconnections with the ventral tegmental nucleus of Gudden) we discuss how the mammillary body-anterior thalamic pathway may contribute to the mechanisms via which the hippocampus and neocortex encode representations of experience.
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Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Michal M Milczarek
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - James C Perry
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Seralynne D Vann
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK.
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12
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Umaba R, Kitanishi T, Mizuseki K. Monosynaptic connection from the subiculum to medial mammillary nucleus neurons projecting to the anterior thalamus and Gudden's ventral tegmental nucleus. Neurosci Res 2021; 171:1-8. [PMID: 33476683 DOI: 10.1016/j.neures.2021.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/29/2020] [Accepted: 01/14/2021] [Indexed: 10/22/2022]
Abstract
As a major hippocampal output structure, the subiculum projects to diverse cortical and subcortical areas, and its projection to the medial mammillary nucleus (MM) has been implicated in memory. Major efferent targets of the MM are the anteroventral and anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus. These projections may play a key role in distributing subicular information. However, it remains unknown whether neurons in the MM that receive monosynaptic input from the subiculum project to these target regions. We addressed this issue with anterograde transsynaptic tracing mediated using adeno-associated virus serotype 1 (AAV1). Injection of AAV1-Cre and a Cre-dependent AAV encoding enhanced yellow fluorescent protein (EYFP) into the rat dorsal subiculum and MM, respectively, labeled the soma of the MM and axons in the anteroventral / anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus with EYFP. The EYFP-positive neurons in the MM were immunoreactive for glutamate and leu-enkephalin and received perisomatic GABAergic inputs. These results revealed monosynaptic projections from the subiculum to MM neurons projecting to the anteroventral / anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus. This monosynaptic connection may support a fast and robust signal flow through the hippocampal-mammillothalamic and hippocampal-mammillotegmental pathways.
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Affiliation(s)
- Ryoko Umaba
- Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan
| | - Takuma Kitanishi
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan.
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13
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Barnett S, Parr-Brownlie L, Perry B, Young C, Wicky H, Hughes S, McNaughton N, Dalrymple-Alford J. Anterior thalamic nuclei neurons sustain memory. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100022. [PMID: 36246504 PMCID: PMC9559952 DOI: 10.1016/j.crneur.2021.100022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/26/2021] [Accepted: 09/20/2021] [Indexed: 12/27/2022] Open
Abstract
A hippocampal-diencephalic-cortical network supports memory function. The anterior thalamic nuclei (ATN) form a key anatomical hub within this system. Consistent with this, injury to the mammillary body-ATN axis is associated with examples of clinical amnesia. However, there is only limited and indirect support that the output of ATN neurons actively enhances memory. Here, in rats, we first showed that mammillothalamic tract (MTT) lesions caused a persistent impairment in spatial working memory. MTT lesions also reduced rhythmic electrical activity across the memory system. Next, we introduced 8.5 Hz optogenetic theta-burst stimulation of the ATN glutamatergic neurons. The exogenously-triggered, regular pattern of stimulation produced an acute and substantial improvement of spatial working memory in rats with MTT lesions and enhanced rhythmic electrical activity. Neither behaviour nor rhythmic activity was affected by endogenous stimulation derived from the dorsal hippocampus. Analysis of immediate early gene activity, after the rats foraged for food in an open field, showed that exogenously-triggered ATN stimulation also increased Zif268 expression across memory-related structures. These findings provide clear evidence that increased ATN neuronal activity supports memory. They suggest that ATN-focused gene therapy may be feasible to counter clinical amnesia associated with dysfunction in the mammillary body-ATN axis. The mammillothalamic tract (MTT) supports neural activity in an extended memory system. Optogenetic activation of neurons in the anterior thalamus acutely improves memory after MTT lesions. Rescued memory associates with system-wide neuronal activation and enhanced EEG. Anterior thalamus actively sustains memory and is a feasible therapeutic target.
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14
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The contribution of mamillary body damage to Wernicke's encephalopathy and Korsakoff's syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2021; 180:455-475. [PMID: 34225949 DOI: 10.1016/b978-0-12-820107-7.00029-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Histopathological alterations of the mamillary bodies are the most conspicuous and the most consistent neuropathological features of several disorders that occur after severe thiamine deficiency, such as Wernicke's encephalopathy and Korsakoff's syndrome. Moreover, they are among the few abnormalities that are visible to the naked eye in these disorders. With a lifetime prevalence of approximately 1.3%, Wernicke's encephalopathy is by far the most frequent cause of damage to the mamillary bodies in humans. Still, there is a persisting uncertainty with regard to the development and the clinical consequences of this damage, because it is virtually impossible to study in isolation. As a rule, it always occurs alongside neuropathology in other subcortical gray matter structures, notably the medial thalamus. Converging evidence from other pathologies and animal experiments is needed to assess the clinical impact of mamillary body damage and to determine which functions can be attributed to these structures in healthy subjects. In this chapter, we describe the history and the current state of knowledge with regard to thiamine deficiency disorders and the contribution of mamillary body damage to their clinical presentations.
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15
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Mathiasen ML, O'Mara SM, Aggleton JP. The anterior thalamic nuclei and nucleus reuniens: So similar but so different. Neurosci Biobehav Rev 2020; 119:268-280. [PMID: 33069688 PMCID: PMC7738755 DOI: 10.1016/j.neubiorev.2020.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/26/2020] [Accepted: 10/05/2020] [Indexed: 12/04/2022]
Abstract
Two thalamic sites are of especial significance for understanding hippocampal - diencephalic interactions: the anterior thalamic nuclei and nucleus reuniens. Both nuclei have dense, direct interconnections with the hippocampal formation, and both are directly connected with many of the same cortical and subcortical areas. These two thalamic sites also contain neurons responsive to spatial stimuli while lesions within these two same areas can disrupt spatial learning tasks that are hippocampal dependent. Despite these many similarities, closer analysis reveals important differences in the details of their connectivity and the behavioural impact of lesions in these two thalamic sites. These nuclei play qualitatively different roles that largely reflect the contrasting relative importance of their medial frontal cortex interactions (nucleus reuniens) compared with their retrosplenial, cingulate, and mammillary body interactions (anterior thalamic nuclei). While the anterior thalamic nuclei are critical for multiple aspects of hippocampal spatial encoding and performance, nucleus reuniens contributes, as required, to aid cognitive control and help select correct from competing memories.
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Affiliation(s)
- Mathias L Mathiasen
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, CF10 3AT, Wales, UK
| | - Shane M O'Mara
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - John P Aggleton
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, CF10 3AT, Wales, UK.
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16
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Mickelsen LE, Flynn WF, Springer K, Wilson L, Beltrami EJ, Bolisetty M, Robson P, Jackson AC. Cellular taxonomy and spatial organization of the murine ventral posterior hypothalamus. eLife 2020; 9:58901. [PMID: 33119507 PMCID: PMC7595735 DOI: 10.7554/elife.58901] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/21/2020] [Indexed: 01/02/2023] Open
Abstract
The ventral posterior hypothalamus (VPH) is an anatomically complex brain region implicated in arousal, reproduction, energy balance, and memory processing. However, neuronal cell type diversity within the VPH is poorly understood, an impediment to deconstructing the roles of distinct VPH circuits in physiology and behavior. To address this question, we employed a droplet-based single-cell RNA sequencing (scRNA-seq) approach to systematically classify molecularly distinct cell populations in the mouse VPH. Analysis of >16,000 single cells revealed 20 neuronal and 18 non-neuronal cell populations, defined by suites of discriminatory markers. We validated differentially expressed genes in selected neuronal populations through fluorescence in situ hybridization (FISH). Focusing on the mammillary bodies (MB), we discovered transcriptionally-distinct clusters that exhibit neuroanatomical parcellation within MB subdivisions and topographic projections to the thalamus. This single-cell transcriptomic atlas of VPH cell types provides a resource for interrogating the circuit-level mechanisms underlying the diverse functions of VPH circuits.
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Affiliation(s)
- Laura E Mickelsen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, United States.,Connecticut Institute for the Brain and Cognitive Sciences, Storrs, United States
| | - William F Flynn
- The Jackson Laboratory for Genomic Medicine, Farmington, United States
| | - Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, United States
| | - Lydia Wilson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, United States
| | - Eric J Beltrami
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, United States
| | - Mohan Bolisetty
- The Jackson Laboratory for Genomic Medicine, Farmington, United States
| | - Paul Robson
- The Jackson Laboratory for Genomic Medicine, Farmington, United States.,Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, United States.,Institute for Systems Genomics, University of Connecticut, Farmington, United States
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, United States.,Connecticut Institute for the Brain and Cognitive Sciences, Storrs, United States.,Institute for Systems Genomics, University of Connecticut, Farmington, United States
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17
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ADHD-like behaviors caused by inactivation of a transcription factor controlling the balance of inhibitory and excitatory neuron development in the mouse anterior brainstem. Transl Psychiatry 2020; 10:357. [PMID: 33087695 PMCID: PMC7578792 DOI: 10.1038/s41398-020-01033-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 07/28/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022] Open
Abstract
The neural circuits regulating motivation and movement include midbrain dopaminergic neurons and associated inhibitory GABAergic and excitatory glutamatergic neurons in the anterior brainstem. Differentiation of specific subtypes of GABAergic and glutamatergic neurons in the mouse embryonic brainstem is controlled by a transcription factor Tal1. This study characterizes the behavioral and neurochemical changes caused by the absence of Tal1 function. The Tal1cko mutant mice are hyperactive, impulsive, hypersensitive to reward, have learning deficits and a habituation defect in a novel environment. Only minor changes in their dopaminergic system were detected. Amphetamine induced striatal dopamine release and amphetamine induced place preference were normal in Tal1cko mice. Increased dopamine signaling failed to stimulate the locomotor activity of the Tal1cko mice, but instead alleviated their hyperactivity. Altogether, the Tal1cko mice recapitulate many features of the attention and hyperactivity disorders, suggesting a role for Tal1 regulated developmental pathways and neural structures in the control of motivation and movement.
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18
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Deconstructing the Direct Reciprocal Hippocampal-Anterior Thalamic Pathways for Spatial Learning. J Neurosci 2020; 40:6978-6990. [PMID: 32753513 PMCID: PMC7470921 DOI: 10.1523/jneurosci.0874-20.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/14/2020] [Accepted: 07/19/2020] [Indexed: 01/13/2023] Open
Abstract
The hippocampus is essential for normal memory but does not act in isolation. The anterior thalamic nuclei may represent one vital partner. Using DREADDs, the behavioral consequences of transiently disrupting anterior thalamic function were examined, followed by inactivation of the dorsal subiculum. Next, the anterograde transport of an adeno-associated virus expressing DREADDs was paired with localized intracerebral infusions of a ligand to target specific input pathways. In this way, the direct projections from the anterior thalamic nuclei to the dorsal hippocampal formation were inhibited, followed by separate inhibition of the dorsal subiculum projections to the anterior thalamic nuclei. To assay spatial working memory, all animals performed a reinforced T-maze alternation task, then a more challenging version that nullifies intramaze cues. Across all four experiments, deficits emerged on the spatial alternation task that precluded the use of intramaze cues. Inhibiting dorsal subiculum projections to the anterior thalamic nuclei produced the severest spatial working memory deficit. This deficit revealed the key contribution of dorsal subiculum projections to the anteromedial and anteroventral thalamic nuclei for the processing of allocentric information, projections not associated with head-direction information. The overall pattern of results provides consistent causal evidence of the two-way functional significance of direct hippocampal-anterior thalamic interactions for spatial processing. At the same time, these findings are consistent with hypotheses that these same, reciprocal interactions underlie the common core symptoms of temporal lobe and diencephalic anterograde amnesia. SIGNIFICANCE STATEMENT It has long been conjectured that the anterior thalamic nuclei might be key partners with the hippocampal formation and that, respectively, they are principally responsible for diencephalic and temporal lobe amnesia. However, direct causal evidence for this functional relationship is lacking. Here, we examined the behavioral consequences of transiently silencing the direct reciprocal interconnections between these two brain regions on tests of spatial learning. Disrupting information flow from the hippocampal formation to the anterior thalamic nuclei and vice versa impaired performance on tests of spatial learning. By revealing the conjoint importance of hippocampal-anterior thalamic pathways, these findings help explain why pathology in either the medial diencephalon or the medial temporal lobes can result in profound anterograde amnesic syndromes.
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19
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Williams AN, Ridgeway S, Postans M, Graham KS, Lawrence AD, Hodgetts CJ. The role of the pre-commissural fornix in episodic autobiographical memory and simulation. Neuropsychologia 2020; 142:107457. [PMID: 32259556 PMCID: PMC7322517 DOI: 10.1016/j.neuropsychologia.2020.107457] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 12/13/2022]
Abstract
Neuropsychological and functional magnetic resonance imaging evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, it is unknown whether hippocampal-vmPFC structural connectivity supports both past- and future-oriented episodic thinking. To address this, we applied a novel deterministic tractography protocol to diffusion-weighted magnetic resonance imaging (dMRI) data from a group of healthy young adult humans who undertook an adapted past-future autobiographical interview (portions of this data were published in Hodgetts et al., 2017a). This tractography protocol enabled distinct subdivisions of the fornix, detected previously in axonal tracer studies, to be reconstructed in vivo, namely the pre-commissural (connecting the hippocampus to vmPFC) and post-commissural (linking the hippocampus and medial diencephalon) fornix. As predicted, we found that inter-individual differences in pre-commissural - but not post-commissural - fornix microstructure (fractional anisotropy) were significantly correlated with the episodic richness of both past and future autobiographical narratives. Notably, these results held when controlling for non-episodic narrative content, verbal fluency, and grey matter volumes of the hippocampus and vmPFC. This study provides novel evidence that reconstructing events from one's personal past, and constructing possible future events, involves a distinct, structurally-instantiated hippocampal-vmPFC pathway.
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Affiliation(s)
- Angharad N Williams
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom; Max Planck Research Group Adaptive Memory, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany.
| | - Samuel Ridgeway
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Mark Postans
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Kim S Graham
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Andrew D Lawrence
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom.
| | - Carl J Hodgetts
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom; Department of Psychology, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, United Kingdom
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20
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Abstract
In this review we briefly outline how lesion studies, temporary inactivation and neural activity assays have helped update functional models of the retrosplenial cortex, a region critical for episodic and spatial memory. We advocate for the continued importance of appropriately designed behavioural studies in the context of novel experimental methods, such as optogenetic and chemogenetic manipulations. At the same time, we caution against the overreliance on any given level of analysis or experimental technique. Complementary, multimodal strategies are required for understanding how the retrosplenial cortex contributes to the formation and storage of memories both at a structural and systems-level.
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21
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Escobar I, Xu J, Jackson CW, Perez-Pinzon MA. Altered Neural Networks in the Papez Circuit: Implications for Cognitive Dysfunction after Cerebral Ischemia. J Alzheimers Dis 2020; 67:425-446. [PMID: 30584147 PMCID: PMC6398564 DOI: 10.3233/jad-180875] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cerebral ischemia remains a leading cause of mortality worldwide. Although the incidence of death has decreased over the years, surviving patients may suffer from long-term cognitive impairments and have an increased risk for dementia. Unfortunately, research aimed toward developing therapies that can improve cognitive outcomes following cerebral ischemia has proved difficult given the fact that little is known about the underlying processes involved. Nevertheless, mechanisms that disrupt neural network activity may provide valuable insight, since disturbances in both local and global networks in the brain have been associated with deficits in cognition. In this review, we suggest that abnormal neural dynamics within different brain networks may arise from disruptions in synaptic plasticity processes and circuitry after ischemia. This discussion primarily concerns disruptions in local network activity within the hippocampus and other extra-hippocampal components of the Papez circuit, given their role in memory processing. However, impaired synaptic plasticity processes and disruptions in structural and functional connections within the Papez circuit have important implications for alterations within the global network, as well. Although much work is required to establish this relationship, evidence thus far suggests there is a link. If pursued further, findings may lead toward a better understanding of how deficits in cognition arise, not only in cerebral ischemia, but in other neurological diseases as well.
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Affiliation(s)
- Iris Escobar
- Department of Neurology, Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jing Xu
- Department of Neurology, Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Charles W Jackson
- Department of Neurology, Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Miguel A Perez-Pinzon
- Department of Neurology, Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
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22
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Kanno N, Fujiwara K, Yoshida S, Kato T, Kato Y. Dynamic Changes in the Localization of Neuronatin-Positive Cells during Neurogenesis in the Embryonic Rat Brain. Cells Tissues Organs 2019; 207:127-137. [DOI: 10.1159/000504359] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 10/24/2019] [Indexed: 11/19/2022] Open
Abstract
Neuronatin (NNAT) was first identified as a gene selectively and abundantly expressed in the cytoplasm of the newborn mouse brain, and involved in neonatal neurogenesis. However, the particular roles of NNAT in the developing prenatal brain have not been identified, especially in mid to late stages. In this study, we performed immunohistochemical analyses of NNAT and SOX2 proteins, a nuclear transcription factor and neural stem/progenitor marker, in the rat brain on embryonic days 13.5, E16.5, and E20.5. NNAT signals were broadly observed across the developing brain on E13.5 and gradually more localized in later stages, eventually concentrated in the alar and basal parts of the terminal hypothalamus, the alar plate of prosomere 2 of the thalamus, and the choroid plexus in the lateral and fourth ventricles on E20.5. In particular, the mammillary body in the basal part of the terminal hypothalamus, a region with a high number of SOX2-positive cells, evidenced intense NNAT signals on E20.5. The intracellular localization of NNAT showed diverse profiles, suggesting that NNAT was involved in various cellular functions, such as cell differentiation and functional maintenance, during prenatal neurogenesis in the rat brain. Thus, the present observations suggested diverse and active roles of the NNAT protein in neurogenesis. Determining the function of this molecule may assist in the elucidation of the mechanisms involved in brain development.
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23
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Shin H, Lee SY, Cho HU, Oh Y, Kim IY, Lee KH, Jang DP, Min HK. Fornix Stimulation Induces Metabolic Activity and Dopaminergic Response in the Nucleus Accumbens. Front Neurosci 2019; 13:1109. [PMID: 31708723 PMCID: PMC6821687 DOI: 10.3389/fnins.2019.01109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 10/01/2019] [Indexed: 12/27/2022] Open
Abstract
The Papez circuit, including the fornix white matter bundle, is a well-known neural network that is involved in multiple limbic functions such as memory and emotional expression. We previously reported a large-animal study of deep brain stimulation (DBS) in the fornix that found stimulation-induced hemodynamic responses in both the medial limbic and corticolimbic circuits on functional resonance imaging (fMRI) and evoked dopamine responses in the nucleus accumbens (NAc), as measured by fast-scan cyclic voltammetry (FSCV). The effects of DBS on the fornix are challenging to analyze, given its structural complexity and connection to multiple neuronal networks. In this study, we extend our earlier work to a rodent model wherein we characterize regional brain activity changes resulting from fornix stimulation using fludeoxyglucose (18F-FDG) micro positron emission tomography (PET) and monitor neurochemical changes using FSCV with pharmacological confirmation. Both global functional changes and local changes were measured in a rodent model of fornix DBS. Functional brain activity was measured by micro-PET, and the neurochemical changes in local areas were monitored by FSCV. Micro-PET images revealed increased glucose metabolism within the medial limbic and corticolimbic circuits. Neurotransmitter efflux induced by fornix DBS was monitored at NAc by FSCV and identified by specific neurotransmitter reuptake inhibitors. We found a significant increase in the metabolic activity in several key regions of the medial limbic circuits and dopamine efflux in the NAc following fornix stimulation. These results suggest that electrical stimulation of the fornix modulates the activity of brain memory circuits, including the hippocampus and NAc within the dopaminergic pathway.
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Affiliation(s)
- Hojin Shin
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, South Korea
| | - Sang-Yoon Lee
- Department of Neuroscience, College of Medicine, Gachon University, Incheon, South Korea
| | - Hyun-U Cho
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, South Korea
| | - Yoonbae Oh
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States
| | - In Young Kim
- Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Dong Pyo Jang
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, South Korea
| | - Hoon-Ki Min
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States.,Department of Radiology, Mayo Clinic, Rochester, MN, United States
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24
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Dillingham CM, Vann SD. Why Isn't the Head Direction System Necessary for Direction? Lessons From the Lateral Mammillary Nuclei. Front Neural Circuits 2019; 13:60. [PMID: 31619970 PMCID: PMC6759954 DOI: 10.3389/fncir.2019.00060] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/26/2019] [Indexed: 11/24/2022] Open
Abstract
Complex spatial representations in the hippocampal formation and related cortical areas require input from the head direction system. However, a recurrent finding is that behavior apparently supported by these spatial representations does not appear to require input from generative head direction regions, i.e., lateral mammillary nuclei (LMN). Spatial tasks that tax direction discrimination should be particularly sensitive to the loss of head direction information, however, this has been repeatedly shown not to be the case. A further dissociation between electrophysiological properties of the head direction system and behavior comes in the form of geometric-based navigation which is impaired following lesions to the head direction system, yet head direction cells are not normally guided by geometric cues. We explore this apparent mismatch between behavioral and electrophysiological studies and highlight future experiments that are needed to generate models that encompass both neurophysiological and behavioral findings.
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Affiliation(s)
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff, United Kingdom
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25
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Dillingham CM, Milczarek MM, Perry JC, Frost BE, Parker GD, Assaf Y, Sengpiel F, O'Mara SM, Vann SD. Mammillothalamic Disconnection Alters Hippocampocortical Oscillatory Activity and Microstructure: Implications for Diencephalic Amnesia. J Neurosci 2019; 39:6696-6713. [PMID: 31235646 PMCID: PMC6703878 DOI: 10.1523/jneurosci.0827-19.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 01/13/2023] Open
Abstract
Diencephalic amnesia can be as debilitating as the more commonly known temporal lobe amnesia, yet the precise contribution of diencephalic structures to memory processes remains elusive. Across four cohorts of male rats, we used discrete lesions of the mammillothalamic tract to model aspects of diencephalic amnesia and assessed the impact of these lesions on multiple measures of activity and plasticity within the hippocampus and retrosplenial cortex. Lesions of the mammillothalamic tract had widespread indirect effects on hippocampocortical oscillatory activity within both theta and gamma bands. Both within-region oscillatory activity and cross-regional synchrony were altered. The network changes were state-dependent, displaying different profiles during locomotion and paradoxical sleep. Consistent with the associations between oscillatory activity and plasticity, complementary analyses using several convergent approaches revealed microstructural changes, which appeared to reflect a suppression of learning-induced plasticity in lesioned animals. Together, these combined findings suggest a mechanism by which damage to the medial diencephalon can impact upon learning and memory processes, highlighting an important role for the mammillary bodies in the coordination of hippocampocortical activity.SIGNIFICANCE STATEMENT Information flow within the Papez circuit is critical to memory. Damage to ascending mammillothalamic projections has consistently been linked to amnesia in humans and spatial memory deficits in animal models. Here we report on the changes in hippocampocortical oscillatory dynamics that result from chronic lesions of the mammillothalamic tract and demonstrate, for the first time, that the mammillary bodies, independently of the supramammillary region, contribute to frequency modulation of hippocampocortical theta oscillations. Consistent with the associations between oscillatory activity and plasticity, the lesions also result in a suppression of learning-induced plasticity. Together, these data support new functional models whereby mammillary bodies are important for coordinating hippocampocortical activity rather than simply being a relay of hippocampal information as previously assumed.
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Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Michal M Milczarek
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - James C Perry
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Bethany E Frost
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Greg D Parker
- EMRIC, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Yaniv Assaf
- George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel 6997801, and
| | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Shane M O'Mara
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom,
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26
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Yu D, Yan H, Zhou J, Yang X, Lu Y, Han Y. A circuit view of deep brain stimulation in Alzheimer's disease and the possible mechanisms. Mol Neurodegener 2019; 14:33. [PMID: 31395077 PMCID: PMC6688355 DOI: 10.1186/s13024-019-0334-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/26/2019] [Indexed: 02/08/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by chronic progressive cognitive deterioration frequently accompanied by psychopathological symptoms, including changes in personality and social isolation, which severely reduce quality of life. Currently, no viable therapies or present-day drugs developed for the treatment of AD symptoms are able to slow or reverse AD progression or prevent the advance of neurodegeneration. As such, non-drug alternatives are currently being tested, including deep brain stimulation (DBS). DBS is an established therapy for several neurological and psychiatric indications, such as movement disorders. Studies assessing DBS for other disorders have also found improvements in cognitive function, providing the impetus for clinical trials on DBS for AD. Targets of DBS in AD clinical trials and animal model studies include the fornix, entorhinal cortex (EC), nucleus basalis of Meynert (NBM), and vertical limb of diagonal band (VDB). However, there is still no comprehensive theory explaining the effects of DBS on AD symptoms or a consensus on which targets provide optimal benefits. This article reviews the anatomy of memory circuits related to AD, as well as studies on DBS rescue of AD in these circuits and the possible therapeutic mechanisms.
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Affiliation(s)
- Danfang Yu
- Department of Neurobiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Neurology, Provincial Hospital of Integrated Chinese & Western Medicine, Wuhan, China
| | - Huanhuan Yan
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Biomedical Engineering Department, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Zhou
- Department of Neurobiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaodan Yang
- Department of Neurobiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Youming Lu
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .,Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, China.
| | - Yunyun Han
- Department of Neurobiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .,Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, China.
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Wolff M, Vann SD. The Cognitive Thalamus as a Gateway to Mental Representations. J Neurosci 2019; 39:3-14. [PMID: 30389839 PMCID: PMC6325267 DOI: 10.1523/jneurosci.0479-18.2018] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/24/2018] [Accepted: 10/28/2018] [Indexed: 01/16/2023] Open
Abstract
Historically, the thalamus has been viewed as little more than a relay, simply transferring information to key players of the cast, the cortex and hippocampus, without providing any unique functional contribution. In recent years, evidence from multiple laboratories researching different thalamic nuclei has contradicted this idea of the thalamus as a passive structure. Dated models of thalamic functions are being pushed aside, revealing a greater and far more complex contribution of the thalamus for cognition. In this Viewpoints article, we show how recent data support novel views of thalamic functions that emphasize integrative roles in cognition, ranging from learning and memory to flexible adaption. We propose that these apparently separate cognitive functions may indeed be supported by a more general role in shaping mental representations. Several features of thalamocortical circuits are consistent with this suggested role, and we highlight how divergent and convergent thalamocortical and corticothalamic pathways may complement each other to support these functions. Furthermore, the role of the thalamus for subcortical integration is highlighted as a key mechanism for maintaining and updating representations. Finally, we discuss future areas of research and stress the importance of incorporating new experimental findings into existing knowledge to continue developing thalamic models. The presence of thalamic pathology in a number of neurological conditions reinforces the need to better understand the role of this region in cognition.
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Affiliation(s)
- Mathieu Wolff
- Centre National de la Recherche Scientifique, INCIA, Unité Mixte de Recherche 5287, Bordeaux, France,
- University of Bordeaux, INCIA, Unité Mixte de Recherche 5287, Bordeaux, France, and
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff, CF10 3AT, United Kingdom
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28
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Hermiller MS, VanHaerents S, Raij T, Voss JL. Frequency-specific noninvasive modulation of memory retrieval and its relationship with hippocampal network connectivity. Hippocampus 2018; 29:595-609. [PMID: 30447076 DOI: 10.1002/hipo.23054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/11/2018] [Indexed: 11/12/2022]
Abstract
Episodic memory is thought to rely on interactions of the hippocampus with other regions of the distributed hippocampal-cortical network (HCN) via interregional activity synchrony in the theta frequency band. We sought to causally test this hypothesis using network-targeted transcranial magnetic stimulation. Healthy human participants completed four experimental sessions, each involving a different stimulation pattern delivered to the same individualized parietal cortex location of the HCN for all sessions. There were three active stimulation conditions, including continuous theta-burst stimulation, intermittent theta-burst stimulation, and beta-frequency (20-Hz) repetitive stimulation, and one sham condition. Resting-state fMRI and episodic memory testing were used to assess the impact of stimulation on hippocampal fMRI connectivity related to retrieval success. We hypothesized that theta-burst stimulation conditions would most strongly influence hippocampal-HCN fMRI connectivity and retrieval, given the hypothesized relevance of theta-band activity for HCN memory function. Continuous theta-burst stimulation improved item retrieval success relative to sham and relative to beta-frequency stimulation, whereas intermittent theta-burst stimulation led to numerical but nonsignificant item retrieval improvement. Mean hippocampal fMRI connectivity did not vary for any stimulation conditions, whereas individual differences in retrieval improvements due to continuous theta-burst stimulation were associated with corresponding increases in fMRI connectivity between the hippocampus and other HCN locations. No such memory-related connectivity effects were identified for the other stimulation conditions, indicating that only continuous theta-burst stimulation affected memory-related hippocampal-HCN connectivity. Furthermore, these effects were specific to the targeted HCN, with no significant memory-related fMRI connectivity effects for two distinct control brain networks. These findings support a causal role for fMRI connectivity of the hippocampus with the HCN in episodic memory retrieval and indicate that contributions of this network to retrieval are particularly sensitive to continuous theta-burst noninvasive stimulation.
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Affiliation(s)
- Molly S Hermiller
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, Illinois
| | - Stephen VanHaerents
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Tommi Raij
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, Illinois.,Center for Brain Stimulation, Shirley Ryan AbilityLab, Chicago, Illinois.,Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Chicago, Illinois
| | - Joel L Voss
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, Illinois.,Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Medical Social Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Barnett SC, Perry BAL, Dalrymple-Alford JC, Parr-Brownlie LC. Optogenetic stimulation: Understanding memory and treating deficits. Hippocampus 2018; 28:457-470. [DOI: 10.1002/hipo.22960] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/24/2018] [Accepted: 05/02/2018] [Indexed: 01/01/2023]
Affiliation(s)
- S. C. Barnett
- Department of Psychology; University of Canterbury; Christchurch 8041 New Zealand
- Brain Research New Zealand; New Zealand
| | - B. A. L. Perry
- Department of Psychology; University of Canterbury; Christchurch 8041 New Zealand
- Brain Research New Zealand; New Zealand
| | - J. C. Dalrymple-Alford
- Department of Psychology; University of Canterbury; Christchurch 8041 New Zealand
- Brain Research New Zealand; New Zealand
- New Zealand Brain Research Institute; Christchurch New Zealand
| | - L. C. Parr-Brownlie
- Brain Research New Zealand; New Zealand
- Department of Anatomy, School of Biomedical Science; Brain Health Research Centre, University of Otago; Dunedin New Zealand
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30
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Dalrymple-Alford JC, Perry BAL. Lesions of the mammillothalamic tract and anterior thalamic nuclei: Response to Vann and Nelson (2018). Hippocampus 2018; 28:694-697. [PMID: 29742808 DOI: 10.1002/hipo.22963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 11/11/2022]
Affiliation(s)
- John C Dalrymple-Alford
- Department of Psychology, New Zealand Brain Research Institute, University of Canterbury and Brain Research New Zealand, Christchurch, 8041, New Zealand
| | - Brook A L Perry
- Department of Experimental Psychology, University of Oxford, Oxford, OX1 3SR, United Kingdom
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31
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Vann SD, Nelson AJD. Anterior thalamic nuclei lesions have a greater impact than mammillothalamic tract lesions on the extended hippocampal system: A reply. Hippocampus 2018; 28:691-693. [PMID: 29671918 DOI: 10.1002/hipo.22953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022]
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32
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Vann SD. Lesions within the head direction system reduce retrosplenial c-fos expression but do not impair performance on a radial-arm maze task. Behav Brain Res 2018; 338:153-158. [PMID: 29079513 PMCID: PMC5701769 DOI: 10.1016/j.bbr.2017.10.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/13/2017] [Accepted: 10/20/2017] [Indexed: 11/15/2022]
Abstract
The lateral mammillary nuclei are a central structure within the head direction system yet there is still relatively little known about how these nuclei contribute to spatial performance. In the present study, rats with selective neurotoxic lesions of the lateral mammillary nuclei were tested on a working memory task in a radial-arm maze. This task requires animals to distinguish between eight radially-oriented arms and remember which arms they have entered within a session. Even though it might have been predicted that this task would heavily tax the head direction system, the lesion rats performed equivalently to their surgical controls on this task; no deficit emerged even when the task was made more difficult by rotating the maze mid-way through testing in order to reduce reliance on intramaze cues. Rats were subsequently tested in the dark to increase the use of internally generated direction cues but the lesion rats remained unimpaired. In contrast, the lateral mammillary nuclei lesions were found to decrease retrosplenial c-Fos levels. These results would suggest that the head direction system is not required for the acquisition of the standard radial-arm maze task. It would also suggest that small decreases in retrosplenial c-Fos are not sufficient to produce behavioural impairments.
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Affiliation(s)
- Seralynne D Vann
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, CF10 3AT, UK.
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33
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Unfolding the cognitive map: The role of hippocampal and extra-hippocampal substrates based on a systems analysis of spatial processing. Neurobiol Learn Mem 2018; 147:90-119. [DOI: 10.1016/j.nlm.2017.11.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 01/03/2023]
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34
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Powell AL, Hindley E, Nelson AJD, Davies M, Amin E, Aggleton JP, Vann SD. Lesions of retrosplenial cortex spare immediate-early gene activity in related limbic regions in the rat. Brain Neurosci Adv 2018; 2:2398212818811235. [PMID: 32166157 PMCID: PMC7058225 DOI: 10.1177/2398212818811235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/14/2018] [Indexed: 12/11/2022] Open
Abstract
The retrosplenial cortex forms part of a network of cortical and subcortical structures that have particular importance for spatial learning and navigation in rodents. This study examined how retrosplenial lesions affect activity in this network by visualising the expression of the immediate-early genes c-fos and zif268 after exposure to a novel location. Groups of rats with extensive cytotoxic lesions (areas 29 and 30) and rats with lesions largely confined to area 30 (dysgranular cortex) were compared with their respective control animals for levels of c-fos expression measured by immunohistochemistry. These cortical lesions had very limited effects on distal c-fos activity. Evidence of a restricted reduction in c-fos activity was seen in the septal dentate gyrus (superior blade) but not in other hippocampal and parahippocampal subareas, nor in the anterior cingulate and prelimbic cortices. Related studies examined zif268 activity in those cases with combined area 29 and 30 lesions. The only clear evidence for reduced zif268 activity following retrosplenial cell loss came from the septal CA3 area. The confined impact of retrosplenial tissue loss is notable as, by the same immediate-early gene measures, retrosplenial cortex is itself highly sensitive to damage in related limbic areas, showing a marked c-fos and zif268 hypoactivity across all of its subareas. This asymmetry in covert pathology may help to explain the apparent disparity between the severity of learning deficits after retrosplenial cortex lesions and after lesions in either the hippocampus or the anterior thalamic nuclei.
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Affiliation(s)
- Anna L Powell
- School of Psychology, Cardiff University, Cardiff, UK
| | - Emma Hindley
- School of Psychology, Cardiff University, Cardiff, UK
| | | | - Moira Davies
- School of Psychology, Cardiff University, Cardiff, UK
| | - Eman Amin
- School of Psychology, Cardiff University, Cardiff, UK
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35
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Perry BAL, Mercer SA, Barnett SC, Lee J, Dalrymple-Alford JC. Anterior thalamic nuclei lesions have a greater impact than mammillothalamic tract lesions on the extended hippocampal system. Hippocampus 2017; 28:121-135. [DOI: 10.1002/hipo.22815] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 11/10/2017] [Accepted: 11/15/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Brook A. L. Perry
- Department of Psychology; University of Canterbury; Christchurch New Zealand
- Brain Research New Zealand, co-hosted by Auckland and Otago Universities; Auckland New Zealand
| | - Stephanie A. Mercer
- Department of Biochemistry; University of Otago; Dunedin
- Brain Research New Zealand, co-hosted by Auckland and Otago Universities; Auckland New Zealand
| | - Sophie C. Barnett
- Department of Psychology; University of Canterbury; Christchurch New Zealand
- Brain Research New Zealand, co-hosted by Auckland and Otago Universities; Auckland New Zealand
| | - Jungah Lee
- Department of Psychology; University of Canterbury; Christchurch New Zealand
| | - John C. Dalrymple-Alford
- Department of Psychology; University of Canterbury; Christchurch New Zealand
- Brain Research New Zealand, co-hosted by Auckland and Otago Universities; Auckland New Zealand
- New Zealand Brain Research Institute; Christchurch New Zealand
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36
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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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37
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Ruan M, Young CK, McNaughton N. Bi-Directional Theta Modulation between the Septo-Hippocampal System and the Mammillary Area in Free-Moving Rats. Front Neural Circuits 2017; 11:62. [PMID: 28955209 PMCID: PMC5600904 DOI: 10.3389/fncir.2017.00062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/25/2017] [Indexed: 01/07/2023] Open
Abstract
Hippocampal (HPC) theta oscillations have long been linked to various functions of the brain. Many cortical and subcortical areas that also exhibit theta oscillations have been linked to functional circuits with the hippocampus on the basis of coupled activities at theta frequencies. We examine, in freely moving rats, the characteristics of diencephalic theta local field potentials (LFPs) recorded in the supramammillary/mammillary (SuM/MM) areas that are bi-directionally connected to the HPC through the septal complex. Using partial directed coherence (PDC), we find support for previous suggestions that SuM modulates HPC theta at higher frequencies. We find weak separation of SuM and MM by dominant theta frequency recorded locally. Contrary to oscillatory cell activities under anesthesia where SuM is insensitive, but MM is sensitive to medial septal (MS) inactivation, theta LFPs persisted and became indistinguishable after MS-inactivation. However, MS-inactivation attenuated SuM/MM theta power, while increasing the frequency of SuM/MM theta. MS-inactivation also reduced root mean squared power in both HPC and SuM/MM equally, but reduced theta power differentially in the time domain. We provide converging evidence that SuM is preferentially involved in coding HPC theta at higher frequencies, and that the MS-HPC circuit normally imposes a frequency-limiting modulation over the SuM/MM area as suggested by cell-based recordings in anesthetized animals. In addition, we provide evidence that the postulated SuM-MS-HPC-MM circuit is under complex bi-directional control, rather than SuM and MM having roles as unidirectional relays in the network.
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Affiliation(s)
- Ming Ruan
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand.,Department of Pediatrics and Neonatal Services, Zhuhai Municipal Women's and Children's HospitalGuangdong, China
| | - Calvin K Young
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand
| | - Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of OtagoDunedin, New Zealand
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38
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The effect of pharmacological inactivation of the mammillary body and anterior thalamic nuclei on hippocampal theta rhythm in urethane-anesthetized rats. Neuroscience 2017; 362:196-205. [PMID: 28844761 DOI: 10.1016/j.neuroscience.2017.08.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/18/2017] [Accepted: 08/23/2017] [Indexed: 02/02/2023]
Abstract
The mammillary body (MB) and the anterior thalamic nuclei (ATN) are closely related structures, which take part in learning and memory processes. However, the exact role of these structures has remained unclear. In both structures neurons firing according to hippocampal theta rhythm have been found, mainly in the medial mammillary nucleus (MM) and anteroventral thalamic nucleus (AV). These neurons are driven by descending projections from the hippocampal formation and are thought to convey theta rhythm back to the hippocampus (HP). We argue that the MB-ATN axis not only relays theta signal, but may also modulate it. To examine it, we performed a pharmacological inactivation of the MM and AV by local infusion of procaine, and measured changes in theta activity in selected structures of the extended hippocampal system in urethane-anesthetized rats. The inactivation of the MM resulted in decrease in EEG power in the HP and AV, the most evidently in the lower theta frequency bands, i.e. 3-5Hz in the HP (down to 9.2% in 3- to 4-Hz band and 37.6% in 4- to 5-Hz band, in comparison to the power in the control conditions) and 3-4Hz in the AV (down to 24.9%). After the AV inactivation, hippocampal EEG power decreased in theta frequency bands of 3-8Hz (down to 61.6% in 6- to 7-Hz band and 69.4% in 7- to 8-Hz band). Our results suggest that the role of the MB-ATN axis in regulating theta rhythm signaling may be much more important than has been speculated so far.
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39
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Nelson AJD, Vann SD. The importance of mammillary body efferents for recency memory: towards a better understanding of diencephalic amnesia. Brain Struct Funct 2016; 222:2143-2156. [PMID: 27783220 PMCID: PMC5504269 DOI: 10.1007/s00429-016-1330-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 10/19/2016] [Indexed: 11/27/2022]
Abstract
Despite being historically one of the first brain regions linked to memory loss, there remains controversy over the core features of diencephalic amnesia as well as the critical site for amnesia to occur. The mammillary bodies and thalamus appear to be the primary locus of pathology in the cases of diencephalic amnesia, but the picture is complicated by the lack of patients with circumscribed damage. Impaired temporal memory is a consistent neuropsychological finding in Korsakoff syndrome patients, but again, it is unclear whether this deficit is attributable to pathology within the diencephalon or concomitant frontal lobe dysfunction. To address these issues, we used an animal model of diencephalic amnesia and examined the effect of mammillothalamic tract lesions on tests of recency memory. The mammillothalamic tract lesions severely disrupted recency judgements involving multiple items but left intact both recency and familiarity judgements for single items. Subsequently, we used disconnection procedures to assess whether this deficit reflects the indirect involvement of the prefrontal cortex. Crossed-lesion rats, with unilateral lesions of the mammillothalamic tract and medial prefrontal cortex in contralateral hemispheres, were unimpaired on the same recency tests. These results provide the first evidence for the selective importance of mammillary body efferents for recency memory. Moreover, this contribution to recency memory is independent of the prefrontal cortex. More broadly, these findings identify how specific diencephalic structures are vital for key elements of event memory.
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Affiliation(s)
- Andrew J D Nelson
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, CF10 3AT, UK.
| | - Seralynne D Vann
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, CF10 3AT, UK
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40
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Jing W, Wang Y, Fang G, Chen M, Xue M, Guo D, Yao D, Xia Y. EEG Bands of Wakeful Rest, Slow-Wave and Rapid-Eye-Movement Sleep at Different Brain Areas in Rats. Front Comput Neurosci 2016; 10:79. [PMID: 27536231 PMCID: PMC4971061 DOI: 10.3389/fncom.2016.00079] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/19/2016] [Indexed: 12/02/2022] Open
Abstract
Accumulating evidence reveals that neuronal oscillations with various frequency bands in the brain have different physiological functions. However, the frequency band divisions in rats were typically based on empirical spectral distribution from limited channels information. In the present study, functionally relevant frequency bands across vigilance states and brain regions were identified using factor analysis based on 9 channels EEG signals recorded from multiple brain areas in rats. We found that frequency band divisions varied both across vigilance states and brain regions. In particular, theta oscillations during REM sleep were subdivided into two bands, 5–7 and 8–11 Hz corresponding to the tonic and phasic stages, respectively. The spindle activities of SWS were different along the anterior-posterior axis, lower oscillations (~16 Hz) in frontal regions and higher in parietal (~21 Hz). The delta and theta activities co-varied in the visual and auditory cortex during wakeful rest. In addition, power spectra of beta oscillations were significantly decreased in association cortex during REM sleep compared with wakeful rest. These results provide us some new insights into understand the brain oscillations across vigilance states, and also indicate that the spatial factor should not be ignored when considering the frequency band divisions in rats.
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Affiliation(s)
- Wei Jing
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Yanran Wang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Guangzhan Fang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences Chengdu, China
| | - Mingming Chen
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Miaomiao Xue
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Daqing Guo
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
| | - Yang Xia
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in BioMedicine, School of Life Science and Technology, University of Electronic Science and Technology of China Chengdu, China
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41
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Sex-specific effects of prenatal chronic mild stress on adult spatial learning capacity and regional glutamate receptor expression profiles. Exp Neurol 2016; 281:66-80. [DOI: 10.1016/j.expneurol.2016.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/04/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022]
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42
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Frizzati A, Milczarek MM, Sengpiel F, Thomas KL, Dillingham CM, Vann SD. Comparable reduction in Zif268 levels and cytochrome oxidase activity in the retrosplenial cortex following mammillothalamic tract lesions. Neuroscience 2016; 330:39-49. [PMID: 27233617 PMCID: PMC4936792 DOI: 10.1016/j.neuroscience.2016.05.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/13/2016] [Accepted: 05/16/2016] [Indexed: 11/19/2022]
Abstract
Mammillothalamic tract lesions impaired T-maze alternation performance. Mammillothalamic tract lesions reduced Zif268 levels in retrosplenial cortex. Mammillothalamic tract lesions reduced cytochrome oxidase in retrosplenial cortex. No changes were found in the dorsal hippocampus. These distal changes may contribute to the memory impairments.
Damage to the mammillothalamic tract (MTT) produces memory impairments in both humans and rats, yet it is still not clear why this diencephalic pathway is vital for memory. One suggestion is that it is an important route for midbrain inputs to reach a wider cortical and subcortical network that supports memory. Consistent with this idea, MTT lesions produce widespread hypoactivity in distal brain regions as measured by the immediate-early gene, c-fos. To determine whether these findings were selective to c-fos or reflected more general changes in neuronal function, we assessed the effects of MTT lesions on the expression of the immediate-early gene protein, Zif268 and the metabolic marker, cytochrome oxidase, in the retrosplenial cortex and hippocampus. The lesions decreased levels of both activity markers in the superficial and deep layers of the retrosplenial cortex in both its granular and dysgranular subregions. In contrast, no significant changes were observed in the hippocampus, despite the MTT-lesioned animals showing marked impairments on T-maze alternation. These findings are consistent with MTT lesions providing important, indirect inputs for normal retrosplenial cortex functioning. These distal functional changes may contribute to the memory impairments observed after MTT lesions.
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Affiliation(s)
- Aura Frizzati
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Michal M Milczarek
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Frank Sengpiel
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Kerrie L Thomas
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Christopher M Dillingham
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK; Institute of Neuroscience, Trinity College Dublin, Lloyd Building, College Green, Dublin 2, Ireland
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3AT, UK.
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43
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Aggleton JP, Pralus A, Nelson AJD, Hornberger M. Thalamic pathology and memory loss in early Alzheimer's disease: moving the focus from the medial temporal lobe to Papez circuit. Brain 2016; 139:1877-90. [PMID: 27190025 PMCID: PMC4939698 DOI: 10.1093/brain/aww083] [Citation(s) in RCA: 240] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/26/2016] [Indexed: 11/13/2022] Open
Abstract
It is widely assumed that incipient protein pathology in the medial temporal lobe instigates the loss of episodic memory in Alzheimer’s disease, one of the earliest cognitive deficits in this type of dementia. Within this region, the hippocampus is seen as the most vital for episodic memory. Consequently, research into the causes of memory loss in Alzheimer’s disease continues to centre on hippocampal dysfunction and how disease-modifying therapies in this region can potentially alleviate memory symptomology. The present review questions this entrenched notion by bringing together findings from post-mortem studies, non-invasive imaging (including studies of presymptomatic, at-risk cases) and genetically modified animal models. The combined evidence indicates that the loss of episodic memory in early Alzheimer’s disease reflects much wider neurodegeneration in an extended mnemonic system (Papez circuit), which critically involves the limbic thalamus. Within this system, the anterior thalamic nuclei are prominent, both for their vital contributions to episodic memory and for how these same nuclei appear vulnerable in prodromal Alzheimer’s disease. As thalamic abnormalities occur in some of the earliest stages of the disease, the idea that such changes are merely secondary to medial temporal lobe dysfunctions is challenged. This alternate view is further strengthened by the interdependent relationship between the anterior thalamic nuclei and retrosplenial cortex, given how dysfunctions in the latter cortical area provide some of the earliest
in vivo
imaging evidence of prodromal Alzheimer’s disease. Appreciating the importance of the anterior thalamic nuclei for memory and attention provides a more balanced understanding of Alzheimer’s disease. Furthermore, this refocus on the limbic thalamus, as well as the rest of Papez circuit, would have significant implications for the diagnostics, modelling, and experimental treatment of cognitive symptoms in Alzheimer’s disease.
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Affiliation(s)
- John P Aggleton
- School of Psychology, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
| | - Agathe Pralus
- Master of Biosciences, ENS de Lyon, 46 allée d'Italie, 69007 Lyon, France
| | - Andrew J D Nelson
- School of Psychology, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
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Hampstead BM, Khoshnoodi M, Yan W, Deshpande G, Sathian K. Patterns of effective connectivity during memory encoding and retrieval differ between patients with mild cognitive impairment and healthy older adults. Neuroimage 2016; 124:997-1008. [PMID: 26458520 PMCID: PMC5619652 DOI: 10.1016/j.neuroimage.2015.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/09/2015] [Accepted: 10/01/2015] [Indexed: 01/04/2023] Open
Abstract
Previous research has shown that there is considerable overlap in the neural networks mediating successful memory encoding and retrieval. However, little is known about how the relevant human brain regions interact during these distinct phases of memory or how such interactions are affected by memory deficits that characterize mild cognitive impairment (MCI), a condition that often precedes dementia due to Alzheimer's disease. Here we employed multivariate Granger causality analysis using autoregressive modeling of inferred neuronal time series obtained by deconvolving the hemodynamic response function from measured blood oxygenation level-dependent (BOLD) time series data, in order to examine the effective connectivity between brain regions during successful encoding and/or retrieval of object location associations in MCI patients and comparable healthy older adults. During encoding, healthy older adults demonstrated a left hemisphere dominant pattern where the inferior frontal junction, anterior intraparietal sulcus (likely involving the parietal eye fields), and posterior cingulate cortex drove activation in most left hemisphere regions and virtually every right hemisphere region tested. These regions are part of a frontoparietal network that mediates top-down cognitive control and is implicated in successful memory formation. In contrast, in the MCI patients, the right frontal eye field drove activation in every left hemisphere region examined, suggesting reliance on more basic visual search processes. Retrieval in the healthy older adults was primarily driven by the right hippocampus with lesser contributions of the right anterior thalamic nuclei and right inferior frontal sulcus, consistent with theoretical models holding the hippocampus as critical for the successful retrieval of memories. The pattern differed in MCI patients, in whom the right inferior frontal junction and right anterior thalamus drove successful memory retrieval, reflecting the characteristic hippocampal dysfunction of these patients. These findings demonstrate that neural network interactions differ markedly between MCI patients and healthy older adults. Future efforts will investigate the impact of cognitive rehabilitation of memory on these connectivity patterns.
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Affiliation(s)
- B M Hampstead
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA 30033, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA 30322, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI 48105, USA.
| | - M Khoshnoodi
- Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - W Yan
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36830, USA
| | - G Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36830, USA; Department of Psychology, Auburn University, Auburn, AL 36830, USA; Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, AL, USA
| | - K Sathian
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA 30033, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA; Department of Psychology, Emory University, Atlanta, GA 30322, USA
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Miquelajáuregui A, Sandoval-Schaefer T, Martínez-Armenta M, Pérez-Martínez L, Cárabez A, Zhao Y, Heide M, Alvarez-Bolado G, Varela-Echavarría A. LIM homeobox protein 5 (Lhx5) is essential for mamillary body development. Front Neuroanat 2015; 9:136. [PMID: 26578897 PMCID: PMC4621302 DOI: 10.3389/fnana.2015.00136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/12/2015] [Indexed: 02/01/2023] Open
Abstract
The mamillary body (MM) is a group of hypothalamic nuclei related to memory and spatial navigation that interconnects hippocampal, thalamic, and tegmental regions. Here we demonstrate that Lhx5, a LIM-HD domain transcription factor expressed early in the developing posterior hypothalamus, is required for the generation of the MM and its derived tracts. The MM markers Foxb1, Sim2, and Lhx1 are absent in Lhx5 knock-out mice from early embryonic stages, suggesting abnormal specification of this region. This was supported by the absence of Nkx2.1 and expansion of Shh in the prospective mamillary area. Interestingly, we also found an ectopic domain expressing Lhx2 and Lhx9 along the anterio-posterior hypothalamic axis. Our results suggest that Lhx5 controls early aspects of hypothalamic development by regulating gene expression and cellular specification in the prospective MM.
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Affiliation(s)
- Amaya Miquelajáuregui
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Teresa Sandoval-Schaefer
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Miriam Martínez-Armenta
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México Cuernavaca, Mexico
| | - Leonor Pérez-Martínez
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México Cuernavaca, Mexico
| | - Alfonso Cárabez
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Yangu Zhao
- Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
| | - Michael Heide
- Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | | | - Alfredo Varela-Echavarría
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
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46
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Heide M, Zhang Y, Zhou X, Zhao T, Miquelajáuregui A, Varela-Echavarría A, Alvarez-Bolado G. Lhx5 controls mamillary differentiation in the developing hypothalamus of the mouse. Front Neuroanat 2015; 9:113. [PMID: 26321924 PMCID: PMC4536661 DOI: 10.3389/fnana.2015.00113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/30/2015] [Indexed: 12/30/2022] Open
Abstract
Acquisition of specific neuronal identity by individual brain nuclei is a key step in brain development. However, how the mechanisms that confer neuronal identity are integrated with upstream regional specification networks is still mysterious. Expression of Sonic hedgehog (Shh), is required for hypothalamic specification and is later downregulated by Tbx3 to allow for the differentiation of the tubero-mamillary region. In this region, the mamillary body (MBO), is a large neuronal aggregate essential for memory formation. To clarify how MBO identity is acquired after regional specification, we investigated Lhx5, a transcription factor with restricted MBO expression. We first generated a hypomorph allele of Lhx5—in homozygotes, the MBO disappears after initial specification. Intriguingly, in these mutants, Tbx3 was downregulated and the Shh expression domain abnormally extended. Microarray analysis and chromatin immunoprecipitation indicated that Lhx5 appears to be involved in Shh downregulation through Tbx3 and activates several MBO-specific regulator and effector genes. Finally, by tracing the caudal hypothalamic cell lineage we show that, in the Lhx5 mutant, at least some MBO cells are present but lack characteristic marker expression. Our work shows how the Lhx5 locus contributes to integrate regional specification pathways with downstream acquisition of neuronal identity in the MBO.
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Affiliation(s)
- Michael Heide
- Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | - Yuanfeng Zhang
- Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | - Xunlei Zhou
- Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | - Tianyu Zhao
- Key Laboratory of Oral Disease and Biomedical Sciences, Stomatological Hospital, Chongqing Medical University Chongqing, China
| | - Amaya Miquelajáuregui
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
| | - Alfredo Varela-Echavarría
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, Mexico
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Dillingham CM, Holmes JD, Wright NF, Erichsen JT, Aggleton JP, Vann SD. Calcium-binding protein immunoreactivity in Gudden's tegmental nuclei and the hippocampal formation: differential co-localization in neurons projecting to the mammillary bodies. Front Neuroanat 2015; 9:103. [PMID: 26300741 PMCID: PMC4523888 DOI: 10.3389/fnana.2015.00103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
The principal projections to the mammillary bodies arise from just two sites, Gudden’s tegmental nuclei (dorsal and ventral nuclei) and the hippocampal formation (subiculum and pre/postsubiculum). The present study sought to compare the neurochemical properties of these mammillary body inputs in the rat, with a focus on calcium-binding proteins. Neuronal calretinin (CR) immunoreactivity was sparse in Gudden’s tegmental nuclei and showed no co-localization with neurons projecting to the mammillary bodies. In contrast, many of the ventral tegmental nucleus of Gudden cell that project to the mammillary bodies were parvalbumin (PV)-positive whereas a smaller number of mammillary inputs stained for calbindin (CB). Only a few mammillary body projection cells in the dorsal tegmental nucleus of Gudden co-localized with PV and none co-localized with CB. A very different pattern was found in the hippocampal formation. Here, a large proportion of postsubiculum cells that project to the mammillary bodies co-localized with CR, but not CB or PV. While many neurons in the dorsal and ventral subiculum projected to the mammillary bodies, these cells did not co-localize with the immunofluorescence of any of the three tested proteins. These findings highlight marked differences between hippocampal and tegmental inputs to the rat mammillary bodies as well as differences between the medial and lateral mammillary systems. These findings also indicate some conserved neurochemical properties in Gudden’s tegmental nuclei across rodents and primates.
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Affiliation(s)
- Christopher M Dillingham
- Behavioural Neuroscience, School of Psychology, Cardiff University Cardiff, UK ; Visual Neuroscience and Molecular Biology, School of Optometry and Vision Sciences, Cardiff University Cardiff, UK
| | - Joshua D Holmes
- Behavioural Neuroscience, School of Psychology, Cardiff University Cardiff, UK
| | - Nicholas F Wright
- Behavioural Neuroscience, School of Psychology, Cardiff University Cardiff, UK
| | - Jonathan T Erichsen
- Visual Neuroscience and Molecular Biology, School of Optometry and Vision Sciences, Cardiff University Cardiff, UK
| | - John P Aggleton
- Behavioural Neuroscience, School of Psychology, Cardiff University Cardiff, UK
| | - Seralynne D Vann
- Behavioural Neuroscience, School of Psychology, Cardiff University Cardiff, UK
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48
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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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49
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Vann SD, Nelson AJD. The mammillary bodies and memory: more than a hippocampal relay. PROGRESS IN BRAIN RESEARCH 2015; 219:163-85. [PMID: 26072239 PMCID: PMC4498492 DOI: 10.1016/bs.pbr.2015.03.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Although the mammillary bodies were one of the first neural structures to be implicated in memory, it has long been assumed that their main function was to act primarily as a hippocampal relay, passing information on to the anterior thalamic nuclei and from there to the cingulate cortex. This view not only afforded the mammillary bodies no independent role in memory, it also neglected the potential significance of other, nonhippocampal, inputs to the mammillary bodies. Recent advances have transformed the picture, revealing that projections from the tegmental nuclei of Gudden, and not the hippocampal formation, are critical for sustaining mammillary body function. By uncovering a role for the mammillary bodies that is independent of its subicular inputs, this work signals the need to consider a wider network of structures that form the neural bases of episodic memory.
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50
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Aggleton JP, Christiansen K. The subiculum: the heart of the extended hippocampal system. PROGRESS IN BRAIN RESEARCH 2015; 219:65-82. [PMID: 26072234 DOI: 10.1016/bs.pbr.2015.03.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
While descriptions of the subiculum often emphasize its role as a recipient of hippocampal inputs, the area also has particular importance as a source of hippocampal projections. The extrinsic projections from the subiculum not only parallel those from hippocampal fields CA1-4 but also terminate in sites that do not receive direct inputs from the rest of the hippocampus. Both electrophysiological and lesion studies reveal how, despite its very dense CA1 inputs, the subiculum has functional properties seemingly independent from the rest of the hippocampus. In understanding the subiculum, it is necessary to appreciate that its connections are topographically organized along all three planes (longitudinal, transverse, and depth). These topographies may enable the subiculum to separate multiple information types and, hence, support multiple functions. The particular significance of the subiculum for learning and memory is underlined by its importance as a source of hippocampal projections to nuclei in the medial diencephalon, which are themselves vital for human memory and rodent spatial learning. Of particular note are its reciprocal connections with the anterior thalamic nuclei, which are not shared by the rest of the hippocampus (CA1-4). These thalamosubiculum connections may be of especial significance for resolving memory problems that suffer high interference and require the flexible use of stimulus representations.
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Affiliation(s)
- John P Aggleton
- School of Psychology, Cardiff University, Cardiff, Wales, UK
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