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Chockanathan U, Padmanabhan K. Differential disruptions in population coding along the dorsal-ventral axis of CA1 in the APP/PS1 mouse model of Aβ pathology. PLoS Comput Biol 2024; 20:e1012085. [PMID: 38709845 PMCID: PMC11098488 DOI: 10.1371/journal.pcbi.1012085] [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: 02/04/2023] [Revised: 05/16/2024] [Accepted: 04/17/2024] [Indexed: 05/08/2024] Open
Abstract
Alzheimer's Disease (AD) is characterized by a range of behavioral alterations, including memory loss and psychiatric symptoms. While there is evidence that molecular pathologies, such as amyloid beta (Aβ), contribute to AD, it remains unclear how this histopathology gives rise to such disparate behavioral deficits. One hypothesis is that Aβ exerts differential effects on neuronal circuits across brain regions, depending on the neurophysiology and connectivity of different areas. To test this, we recorded from large neuronal populations in dorsal CA1 (dCA1) and ventral CA1 (vCA1), two hippocampal areas known to be structurally and functionally diverse, in the APP/PS1 mouse model of amyloidosis. Despite similar levels of Aβ pathology, dCA1 and vCA1 showed distinct disruptions in neuronal population activity as animals navigated a virtual reality environment. In dCA1, pairwise correlations and entropy, a measure of the diversity of activity patterns, were decreased in APP/PS1 mice relative to age-matched C57BL/6 controls. However, in vCA1, APP/PS1 mice had increased pair-wise correlations and entropy as compared to age matched controls. Finally, using maximum entropy models, we connected the microscopic features of population activity (correlations) to the macroscopic features of the population code (entropy). We found that the models' performance increased in predicting dCA1 activity, but decreased in predicting vCA1 activity, in APP/PS1 mice relative to the controls. Taken together, we found that Aβ exerts distinct effects across different hippocampal regions, suggesting that the various behavioral deficits of AD may reflect underlying heterogeneities in neuronal circuits and the different disruptions that Aβ pathology causes in those circuits.
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Affiliation(s)
- Udaysankar Chockanathan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Krishnan Padmanabhan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Center for Visual Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Intellectual and Developmental Disabilities Research Center, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
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2
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Slutsky I. Linking activity dyshomeostasis and sleep disturbances in Alzheimer disease. Nat Rev Neurosci 2024; 25:272-284. [PMID: 38374463 DOI: 10.1038/s41583-024-00797-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 02/21/2024]
Abstract
The presymptomatic phase of Alzheimer disease (AD) starts with the deposition of amyloid-β in the cortex and begins a decade or more before the emergence of cognitive decline. The trajectory towards dementia and neurodegeneration is shaped by the pathological load and the resilience of neural circuits to the effects of this pathology. In this Perspective, I focus on recent advances that have uncovered the vulnerability of neural circuits at early stages of AD to hyperexcitability, particularly when the brain is in a low-arousal states (such as sleep and anaesthesia). Notably, this hyperexcitability manifests before overt symptoms such as sleep and memory deficits. Using the principles of control theory, I analyse the bidirectional relationship between homeostasis of neuronal activity and sleep and propose that impaired activity homeostasis during sleep leads to hyperexcitability and subsequent sleep disturbances, whereas sleep disturbances mitigate hyperexcitability via negative feedback. Understanding the interplay among activity homeostasis, neuronal excitability and sleep is crucial for elucidating the mechanisms of vulnerability to and resilience against AD pathology and for identifying new therapeutic avenues.
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Affiliation(s)
- Inna Slutsky
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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3
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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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4
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García-Carlos CA, Basurto-Islas G, Perry G, Mondragón-Rodríguez S. Meta-Analysis in Transgenic Alzheimer's Disease Mouse Models Reveals Opposite Brain Network Effects of Amyloid-β and Phosphorylated Tau Proteins. J Alzheimers Dis 2024; 99:595-607. [PMID: 38669540 DOI: 10.3233/jad-231365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Background Cognitive deficits observed in Alzheimer's disease (AD) patients have been correlated with altered hippocampal activity. Although the mechanism remains under extensive study, neurofibrillary tangles and amyloid plaques have been proposed as responsible for brain activity alterations. Aiming to unveil the mechanism, researchers have developed several transgenic models of AD. Nevertheless, the variability in hippocampal oscillatory alterations found in different genetic backgrounds and ages remains unclear. Objective To assess the oscillatory alterations in relation to animal developmental age and protein inclusion, amyloid-β (Aβ) load, and abnormally phosphorylated tau (pTau), we reviewed and analyzed the published data on peak power, frequency, and quantification of theta-gamma cross-frequency coupling (modulation index values). Methods To ensure that the search was as current as possible, a systematic review was conducted to locate and abstract all studies published from January 2000 to February 2023 that involved in vivo hippocampal local field potential recording in transgenic mouse models of AD. Results The presence of Aβ was associated with electrophysiological alterations that are mainly reflected in power increases, frequency decreases, and lower modulation index values. Concomitantly, pTau accumulation was associated with electrophysiological alterations that are mainly reflected in power decreases, frequency decreases, and no significant alterations in modulation index values. Conclusions In this study, we showed that electrophysiological parameters are altered from prodromal stages to the late stages of pathology. Thus, we found that Aβ deposition is associated with brain network hyperexcitability, whereas pTau deposition mainly leads to brain network hypoexcitability in transgenic models.
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Affiliation(s)
- Carlos Antonio García-Carlos
- UNAM Division of Neurosciences, Institute of Cellular Physiology, National Autonomous University of México, México City, México
| | | | - George Perry
- UTSA Neuroscience Institute and Department of Biology, College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Siddhartha Mondragón-Rodríguez
- UAQ Centre for Applied Biomedical Research - CIBA, School of Medicine, Autonomous University of Querétaro, Querétaro, México
- CONAHCYT National Council for Science and Technology, México City, México
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5
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Inayat S, McAllister BB, Chang H, Lacoursiere SG, Whishaw IQ, Sutherland RJ, Mohajerani MH. Weak-hyperactive hippocampal CA1 neurons in the prodromal stage of Alzheimer's disease in hybrid App NL-G-F/NL-G-F × Thy1-GCaMP6s +/- mice suggest disrupted plasticity. Neurobiol Aging 2023; 130:154-171. [PMID: 37531809 DOI: 10.1016/j.neurobiolaging.2023.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 05/13/2023] [Accepted: 06/03/2023] [Indexed: 08/04/2023]
Abstract
This study investigated the impact of familial Alzheimer's disease (AD)-linked amyloid precursor protein (App) mutations on hippocampal CA1 neuronal activity and function at an early disease stage in AppNL-G-F/NL-G-F × Thy1-GCaMP6s+/- (A-TG) mice using calcium imaging. Longitudinal assessment of spatial behavior at 12 and 18 months of age identified an early disease stage at 12 months when there was significant amyloid beta pathology with mild behavioral deficits. Hippocampal CA1 neuronal activity and event-related encoding of distance and time were therefore assessed at 12 months of age in several configurations of an air-induced running task to assess the dynamics of cellular activity. Neurons in A-TG mice displayed diminished (weaker) and more frequent (hyperactive) neuronal firing that was more pronounced during movement compared to immobility. Responsive neurons showed configuration-specific deficits in distance and time encoding with impairment in adapting their responses to changing configurations. These results suggest that at an early stage of AD in the absence of full-blown behavioral deficits, weak-hyperactive neuronal activity may induce impairments in sensory perception of changing environments.
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Affiliation(s)
- Samsoon Inayat
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
| | - Brendan B McAllister
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - HaoRan Chang
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Sean G Lacoursiere
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ian Q Whishaw
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Robert J Sutherland
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Majid H Mohajerani
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
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6
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Reekes TH, Devinney MJ, Berger M. Amyloid beta and postoperative delirium: partners in crime or strangers in the dark? Br J Anaesth 2023; 131:205-208. [PMID: 37330308 DOI: 10.1016/j.bja.2023.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 06/19/2023] Open
Abstract
Postoperative delirium is a particularly debilitating complication of surgery and perioperative care. Although the aetiology of postoperative delirium is not entirely understood, recent evidence suggests that Alzheimer's disease and related dementias pathology plays an important role in the development of postoperative delirium. A recent study evaluating postoperative changes in plasma beta amyloid (Aβ) levels found increased Aβ across the postoperative period, but the association with postoperative delirium incidence and severity was variable. These findings support the idea that Alzheimer's disease and related dementias pathology in combination with blood-brain barrier dysfunction and neuroinflammation may impart risk for postoperative delirium.
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Affiliation(s)
- Tyler H Reekes
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Michael J Devinney
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Miles Berger
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA; Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC, USA; Center for Cognitive Neuroscience, Duke University, Durham, NC, USA.
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7
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Soula M, Maslarova A, Harvey RE, Valero M, Brandner S, Hamer H, Fernández-Ruiz A, Buzsáki G. Interictal epileptiform discharges affect memory in an Alzheimer's Disease mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528683. [PMID: 36824810 PMCID: PMC9949089 DOI: 10.1101/2023.02.15.528683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Interictal epileptiform discharges (IEDs) are transient abnormal electrophysiological events commonly observed in epilepsy patients but are also present in other neurological disease, such as Alzheimer's Disease (AD). Understanding the role IEDs have on the hippocampal circuit is important for our understanding of the cognitive deficits seen in epilepsy and AD. We characterize and compare the IEDs of human epilepsy patients from microwire hippocampal recording with those of AD transgenic mice with implanted multi-layer hippocampal silicon probes. Both the local field potential features and firing patterns of pyramidal cells and interneurons were similar in mouse and human. We found that as IEDs emerged from the CA3-1 circuits, they recruited pyramidal cells and silenced interneurons, followed by post-IED suppression. IEDs suppressed the incidence and altered the properties of physiological sharp-wave ripples (SPW-Rs), altered their physiological properties, and interfered with the replay of place field sequences in a maze. In addition, IEDs in AD mice inversely correlated with daily memory performance. Together, our work implicates that IEDs may present a common and epilepsy-independent phenomenon in neurodegenerative diseases that perturbs hippocampal-cortical communication and interferes with memory. Significant Statement Prevalence of neurodegenerative diseases and the number of people with dementia is increasing steadily. Therefore, novel treatment strategies for learning and memory disorders are urgently necessary. IEDs, apart from being a surrogate for epileptic brain regions, have also been linked to cognitive decline. Here we report that IEDs in human epilepsy patients and AD mouse models have similar local field potential characteristics and associated firing patterns of pyramidal cells and interneurons. Mice with more IEDs displayed fewer hippocampal SPW-Rs, poorer replay of spatial trajectories, and decreased memory performance. IED suppression is an unexplored target to treat cognitive dysfunction in neurodegenerative diseases.
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8
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Silva A, Martínez MC. Spatial memory deficits in Alzheimer's disease and their connection to cognitive maps' formation by place cells and grid cells. Front Behav Neurosci 2023; 16:1082158. [PMID: 36710956 PMCID: PMC9878455 DOI: 10.3389/fnbeh.2022.1082158] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/28/2022] [Indexed: 01/14/2023] Open
Abstract
Whenever we navigate through different contexts, we build a cognitive map: an internal representation of the territory. Spatial navigation is a complex skill that involves multiple types of information processing and integration. Place cells and grid cells, collectively with other hippocampal and medial entorhinal cortex neurons (MEC), form a neural network whose activity is critical for the representation of self-position and orientation along with spatial memory retrieval. Furthermore, this activity generates new representations adapting to changes in the environment. Though there is a normal decline in spatial memory related to aging, this is dramatically increased in pathological conditions such as Alzheimer's disease (AD). AD is a multi-factorial neurodegenerative disorder affecting mainly the hippocampus-entorhinal cortex (HP-EC) circuit. Consequently, the initial stages of the disease have disorientation and wandering behavior as two of its hallmarks. Recent electrophysiological studies have linked spatial memory deficits to difficulties in spatial information encoding. Here we will discuss map impairment and remapping disruption in the HP-EC network, as a possible circuit mechanism involved in the spatial memory and navigation deficits observed in AD, pointing out the benefits of virtual reality as a tool for early diagnosis and rehabilitation.
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Affiliation(s)
- Azul Silva
- Facultad de Ciencias Médicas, Universidad de Buenos Aires, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Fisiología y Biofísica “Dr. Bernardo Houssay”- CONICET (IFIBIO), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Cecilia Martínez
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Fisiología y Biofísica “Dr. Bernardo Houssay”- CONICET (IFIBIO), Universidad de Buenos Aires, Buenos Aires, Argentina,Facultad de Ciencias Exactas y Naturales, Departamento de Biología Molecular y Celular “Dr. Héctor Maldonado”, Universidad de Buenos Aires, Buenos Aires, Argentina,*Correspondence: María Cecilia Martínez,
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9
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Cheron G, Ristori D, Marquez-Ruiz J, Cebolla AM, Ris L. Electrophysiological alterations of the Purkinje cells and deep cerebellar neurons in a mouse model of Alzheimer disease (electrophysiology on cerebellum of AD mice). Eur J Neurosci 2022; 56:5547-5563. [PMID: 35141975 DOI: 10.1111/ejn.15621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/16/2021] [Accepted: 12/19/2021] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease is histopathologically well defined by the presence of amyloid deposits and tau-related neurofibrillary tangles in crucial regions of the brain. Interest is growing in revealing and determining possible pathological markers also in the cerebellum as its involvement in cognitive functions is now well supported. Despite the central position of the Purkinje cell in the cerebellum, its electrophysiological behaviour in mouse models of Alzheimer's disease is scarce in the literature. Our first aim was here to focus on the electrophysiological behaviour of the cerebellum in awake mouse model of Alzheimer's disease (APPswe/PSEN1dE9) and the related performance on the water-maze test classically used in behavioural studies. We found prevalent signs of electrophysiological alterations in both Purkinje cells and deep cerebellar nuclei neurons which might explain the behavioural deficits reported during the water-maze test. The alterations of neurons firing were accompanied by a dual (~16 and ~228 Hz) local field potential's oscillation in the Purkinje cell layer of Alzheimer's disease mice which was concomitant to an important increase of both the simple and the complex spikes. In addition, β-amyloid deposits were present in the molecular layer of the cerebellum. These results highlight the importance of the output firing modification of the AD cerebellum that may indirectly impact the activity of its subcortical and cortical targets.
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Affiliation(s)
- Guy Cheron
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, Brussels, Belgium.,ULB Neuroscience Institut, Université Libre de Bruxelles, Brussels, Belgium.,Laboratory of Neuroscience, Université de Mons, Mons, Belgium
| | - Dominique Ristori
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, Brussels, Belgium
| | - Javier Marquez-Ruiz
- Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Seville, Spain
| | - Anna-Maria Cebolla
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, Brussels, Belgium
| | - Laurence Ris
- Laboratory of Neuroscience, Université de Mons, Mons, Belgium.,UMONS Research Institut for health and technology, Université de Mons, Mons, Belgium
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10
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Chockanathan U, Padmanabhan K. From synapses to circuits and back: Bridging levels of understanding in animal models of Alzheimer's disease. Eur J Neurosci 2022; 56:5564-5586. [PMID: 35244297 PMCID: PMC10926359 DOI: 10.1111/ejn.15636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/04/2022] [Accepted: 02/23/2022] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by behavioural changes that include memory loss and cognitive decline and is associated with the appearance of amyloid-β plaques and neurofibrillary tangles throughout the brain. Although aspects of the disease percolate across multiple levels of neuronal organization, from the cellular to the behavioural, it is increasingly clear that circuits are a critical junction between the cellular pathology and the behavioural phenotypes that bookend these levels of analyses. In this review, we discuss critical aspects of neural circuit research, beginning with synapses and progressing to network activity and how they influence our understanding of disease processed in AD.
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Affiliation(s)
- Udaysankar Chockanathan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Krishnan Padmanabhan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Center for Visual Science, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Intellectual and Developmental Disabilities Research Center, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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11
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Theta and gamma oscillatory dynamics in mouse models of Alzheimer's disease: A path to prospective therapeutic intervention. Neurosci Biobehav Rev 2022; 136:104628. [PMID: 35331816 DOI: 10.1016/j.neubiorev.2022.104628] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 12/26/2022]
Abstract
Understanding the neural basis of cognitive deficits, a key feature of Alzheimer's disease (AD), is imperative for achieving the therapy of the disease. Rhythmic oscillatory activities in neural systems are a fundamental mechanism for diverse brain functions, including cognition. In several neurological conditions like AD, aberrant neural oscillations have been shown to play a central role. Furthermore, manipulation of brain oscillations in animals has confirmed their impact on cognition and disease. In this article, we review the evidence from mouse models that shows how synchronized oscillatory activity is intricately linked to AD machinery. We primarily focus on recent reports showing abnormal oscillatory activities at theta and gamma frequencies in AD condition and their influence on cellular disturbances and cognitive impairments. A thorough comprehension of the role that neuronal oscillations play in AD pathology should pave the way to therapeutic interventions that can curb the disease.
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12
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Jones EAA, Rao A, Zilberter M, Djukic B, Bant JS, Gillespie AK, Koutsodendris N, Nelson M, Yoon SY, Huang K, Yuan H, Gill TM, Huang Y, Frank LM. Dentate gyrus and CA3 GABAergic interneurons bidirectionally modulate signatures of internal and external drive to CA1. Cell Rep 2021; 37:110159. [PMID: 34965435 PMCID: PMC9069800 DOI: 10.1016/j.celrep.2021.110159] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 10/04/2021] [Accepted: 12/01/2021] [Indexed: 01/19/2023] Open
Abstract
Specific classes of GABAergic neurons play specific roles in regulating information processing in the brain. In the hippocampus, two major classes, parvalbumin-expressing (PV+) and somatostatin-expressing (SST+), differentially regulate endogenous firing patterns and target subcellular compartments of principal cells. How these classes regulate the flow of information throughout the hippocampus is poorly understood. We hypothesize that PV+ and SST+ interneurons in the dentate gyrus (DG) and CA3 differentially modulate CA3 patterns of output, thereby altering the influence of CA3 on CA1. We find that while suppressing either interneuron class increases DG and CA3 output, the effects on CA1 were very different. Suppressing PV+ interneurons increases local field potential signatures of coupling from CA3 to CA1 and decreases signatures of coupling from entorhinal cortex to CA1; suppressing SST+ interneurons has the opposite effect. Thus, DG and CA3 PV+ and SST+ interneurons bidirectionally modulate the flow of information through the hippocampal circuit.
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Affiliation(s)
- Emily A. Aery Jones
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.,Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143, USA
| | - Antara Rao
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.,Developmental & Stem Cell Biology Graduate Program, University of California, San Francisco, CA 94143, USA
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Biljana Djukic
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Jason S. Bant
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Anna K. Gillespie
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, CA 94143, USA
| | - Nicole Koutsodendris
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.,Developmental & Stem Cell Biology Graduate Program, University of California, San Francisco, CA 94143, USA
| | - Maxine Nelson
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.,Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143, USA
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Ky Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Heidi Yuan
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Theodore M. Gill
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.,Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143, USA,Developmental & Stem Cell Biology Graduate Program, University of California, San Francisco, CA 94143, USA,Departments of Neurology and Pathology, University of California, San Francisco, CA 94143, USA,Gladstone Center for Translational Advancement, San Francisco, CA 94158, USA,Correspondence should be addressed to: Loren Frank () or Yadong Huang ()
| | - Loren M. Frank
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, CA 94143, USA,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA,Lead contact,Correspondence should be addressed to: Loren Frank () or Yadong Huang ()
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13
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Segen V, Ying J, Morgan E, Brandon M, Wolbers T. Path integration in normal aging and Alzheimer's disease. Trends Cogn Sci 2021; 26:142-158. [PMID: 34872838 DOI: 10.1016/j.tics.2021.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 12/20/2022]
Abstract
In this review we discuss converging evidence from human and rodent research demonstrating how path integration (PI) is impaired in healthy aging and Alzheimer's disease (AD), and point to the neural mechanisms that underlie these deficits. Importantly, we highlight that (i) the grid cell network in the entorhinal cortex is crucial for PI in both humans and rodents, (ii) PI deficits are present in healthy aging and are significantly more pronounced in patients with early-stage AD, (iii) compromised entorhinal grid cell computations in healthy older adults and in young adults at risk of AD are linked to PI deficits, and (iv) PI and grid cell deficits may serve as sensitive markers for pathological decline in early AD.
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Affiliation(s)
- Vladislava Segen
- Aging and Cognition Research Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg 39120, Germany.
| | - Johnson Ying
- Douglas Hospital Research Center, McGill University, Montreal, QC, Canada
| | - Erik Morgan
- Douglas Hospital Research Center, McGill University, Montreal, QC, Canada
| | - Mark Brandon
- Douglas Hospital Research Center, McGill University, Montreal, QC, Canada
| | - Thomas Wolbers
- Aging and Cognition Research Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg 39120, Germany.
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14
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Rechnitz O, Slutsky I, Morris G, Derdikman D. Hippocampal sub-networks exhibit distinct spatial representation deficits in Alzheimer's disease model mice. Curr Biol 2021; 31:3292-3302.e6. [PMID: 34146487 DOI: 10.1016/j.cub.2021.05.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 01/03/2021] [Accepted: 05/18/2021] [Indexed: 12/25/2022]
Abstract
Not much is known about how the dentate gyrus (DG) and hippocampal CA3 networks, critical for memory and spatial processing, malfunction in Alzheimer's disease (AD). While studies of associative memory deficits in AD have focused mainly on behavior, here, we directly measured neurophysiological network dysfunction. We asked what the pattern of deterioration of different networks is during disease progression. We investigated how the associative memory-processing capabilities in different hippocampal subfields are affected by familial AD (fAD) mutations leading to amyloid-β dyshomeostasis. Specifically, we focused on the DG and CA3, which are known to be involved in pattern completion and separation and are susceptible to pathological alterations in AD. To identify AD-related deficits in neural-ensemble dynamics, we recorded single-unit activity in wild-type (WT) and fAD model mice (APPSwe+PSEN1/ΔE9) in a novel tactile morph task, which utilizes the extremely developed somatosensory modality of mice. As expected from the sub-network regional specialization, we found that tactile changes induced lower rate map correlations in the DG than in CA3 of WT mice. This reflects DG pattern separation and CA3 pattern completion. In contrast, in fAD model mice, we observed pattern separation deficits in the DG and pattern completion deficits in CA3. This demonstration of region-dependent impairments in fAD model mice contributes to understanding of brain networks deterioration during fAD progression. Furthermore, it implies that the deterioration cannot be studied generally throughout the hippocampus but must be researched at a finer resolution of microcircuits. This opens novel systems-level approaches for analyzing AD-related neural network deficits.
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Affiliation(s)
- Ohad Rechnitz
- Department of Neuroscience, Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, 31096 Haifa, Israel
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Genela Morris
- Department of Neuroscience, Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, 31096 Haifa, Israel
| | - Dori Derdikman
- Department of Neuroscience, Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, 31096 Haifa, Israel.
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15
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Takamura R, Mizuta K, Sekine Y, Islam T, Saito T, Sato M, Ohkura M, Nakai J, Ohshima T, Saido TC, Hayashi Y. Modality-Specific Impairment of Hippocampal CA1 Neurons of Alzheimer's Disease Model Mice. J Neurosci 2021; 41:5315-5329. [PMID: 33980545 PMCID: PMC8211543 DOI: 10.1523/jneurosci.0208-21.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/10/2021] [Accepted: 04/23/2021] [Indexed: 11/21/2022] Open
Abstract
Impairment of episodic memory, a class of memory for spatiotemporal context of an event, is an early symptom of Alzheimer's disease. Both spatial and temporal information are encoded and represented in the hippocampal neurons, but how these representations are impaired under amyloid β (Aβ) pathology remains elusive. We performed chronic imaging of the hippocampus in awake male amyloid precursor protein (App) knock-in mice behaving in a virtual reality environment to simultaneously monitor spatiotemporal representations and the progression of Aβ depositions. We found that temporal representation is preserved, whereas spatial representation is significantly impaired in the App knock-in mice. This is because of the overall reduction of active place cells, but not time cells, and compensatory hyperactivation of remaining place cells near Aβ aggregates. These results indicate the differential impact of Aβ aggregates on two major modalities of episodic memory, suggesting different mechanisms for forming and maintaining these two representations in the hippocampus.
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Affiliation(s)
- Risa Takamura
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480, Japan
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Kotaro Mizuta
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Yukiko Sekine
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Tanvir Islam
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Takashi Saito
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Masaaki Sato
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Masamichi Ohkura
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Junichi Nakai
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Toshio Ohshima
- Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480, Japan
| | - Takaomi C Saido
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
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16
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Vitale P, Salgueiro-Pereira AR, Lupascu CA, Willem M, Migliore R, Migliore M, Marie H. Analysis of Age-Dependent Alterations in Excitability Properties of CA1 Pyramidal Neurons in an APPPS1 Model of Alzheimer's Disease. Front Aging Neurosci 2021; 13:668948. [PMID: 34177555 PMCID: PMC8230571 DOI: 10.3389/fnagi.2021.668948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/14/2021] [Indexed: 11/29/2022] Open
Abstract
Age-dependent accumulation of amyloid-β, provoking increasing brain amyloidopathy, triggers abnormal patterns of neuron activity and circuit synchronization in Alzheimer’s disease (AD) as observed in human AD patients and AD mouse models. Recent studies on AD mouse models, mimicking this age-dependent amyloidopathy, identified alterations in CA1 neuron excitability. However, these models generally also overexpress mutated amyloid precursor protein (APP) and presenilin 1 (PS1) and there is a lack of a clear correlation of neuronal excitability alterations with progressive amyloidopathy. The active development of computational models of AD points out the need of collecting such experimental data to build a reliable disease model exhibiting AD-like disease progression. We therefore used the feature extraction tool of the Human Brain Project (HBP) Brain Simulation Platform to systematically analyze the excitability profile of CA1 pyramidal neuron in the APPPS1 mouse model. We identified specific features of neuron excitability that best correlate either with over-expression of mutated APP and PS1 or increasing Aβ amyloidopathy. Notably, we report strong alterations in membrane time constant and action potential width and weak alterations in firing behavior. Also, using a CA1 pyramidal neuron model, we evidence amyloidopathy-dependent alterations in Ih. Finally, cluster analysis of these recordings showed that we could reliably assign a trace to its correct group, opening the door to a more refined, less variable analysis of AD-affected neurons. This inter-disciplinary analysis, bringing together experimentalists and modelers, helps to further unravel the neuronal mechanisms most affected by AD and to build a biologically plausible computational model of the AD brain.
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Affiliation(s)
- Paola Vitale
- Institute of Biophysics, National Research Council, Palermo, Italy
| | | | | | - Michael Willem
- Biomedical Center, Ludwig Maximilian University of Munich, Munich, Germany
| | - Rosanna Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Hélène Marie
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France
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17
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Chen JF, Liu K, Hu B, Li RR, Xin W, Chen H, Wang F, Chen L, Li RX, Ren SY, Xiao L, Chan JR, Mei F. Enhancing myelin renewal reverses cognitive dysfunction in a murine model of Alzheimer's disease. Neuron 2021; 109:2292-2307.e5. [PMID: 34102111 DOI: 10.1016/j.neuron.2021.05.012] [Citation(s) in RCA: 151] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/15/2021] [Accepted: 05/10/2021] [Indexed: 12/13/2022]
Abstract
Severe cognitive decline is a hallmark of Alzheimer's disease (AD). In addition to gray matter loss, significant white matter pathology has been identified in AD patients. Here, we characterized the dynamics of myelin generation and loss in the APP/PS1 mouse model of AD. Unexpectedly, we observed a dramatic increase in the rate of new myelin formation in APP/PS1 mice, reminiscent of the robust oligodendroglial response to demyelination. Despite this increase, overall levels of myelination are decreased in the cortex and hippocampus of APP/PS1 mice and postmortem AD tissue. Genetically or pharmacologically enhancing myelin renewal, by oligodendroglial deletion of the muscarinic M1 receptor or systemic administration of the pro-myelinating drug clemastine, improved the performance of APP/PS1 mice in memory-related tasks and increased hippocampal sharp wave ripples. Taken together, these results demonstrate the potential of enhancing myelination as a therapeutic strategy to alleviate AD-related cognitive impairment.
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Affiliation(s)
- Jing-Fei Chen
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Kun Liu
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Bo Hu
- Department of Physiology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing 400038, China
| | - Rong-Rong Li
- Department of Physiology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing 400038, China
| | - Wendy Xin
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hao Chen
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Fei Wang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Lin Chen
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Rui-Xue Li
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Shu-Yu Ren
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China
| | - Lan Xiao
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China.
| | - Jonah R Chan
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Feng Mei
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, China.
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18
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Ness N, Schultz SR. A computational grid-to-place-cell transformation model indicates a synaptic driver of place cell impairment in early-stage Alzheimer's Disease. PLoS Comput Biol 2021; 17:e1009115. [PMID: 34133417 PMCID: PMC8238223 DOI: 10.1371/journal.pcbi.1009115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 06/28/2021] [Accepted: 05/26/2021] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's Disease (AD) is characterized by progressive neurodegeneration and cognitive impairment. Synaptic dysfunction is an established early symptom, which correlates strongly with cognitive decline, and is hypothesised to mediate the diverse neuronal network abnormalities observed in AD. However, how synaptic dysfunction contributes to network pathology and cognitive impairment in AD remains elusive. Here, we present a grid-cell-to-place-cell transformation model of long-term CA1 place cell dynamics to interrogate the effect of synaptic loss on network function and environmental representation. Synapse loss modelled after experimental observations in the APP/PS1 mouse model was found to induce firing rate alterations and place cell abnormalities that have previously been observed in AD mouse models, including enlarged place fields and lower across-session stability of place fields. Our results support the hypothesis that synaptic dysfunction underlies cognitive deficits, and demonstrate how impaired environmental representation may arise in the early stages of AD. We further propose that dysfunction of excitatory and inhibitory inputs to CA1 pyramidal cells may cause distinct impairments in place cell function, namely reduced stability and place map resolution.
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Affiliation(s)
- Natalie Ness
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Simon R. Schultz
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, United Kingdom
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19
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Wirt RA, McNeela AM, Hyman JM. Spatial Cognition: Prenatal Alcohol Exposure and the Memory Puzzle. Curr Biol 2021; 30:R1058-R1061. [PMID: 32961165 DOI: 10.1016/j.cub.2020.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We navigate through space using the coordinated activity of spatially sensitive cells in the hippocampus. A new study shows that moderate prenatal alcohol exposure alters multiple features of hippocampal spatial responses, leading to inflexible and less precise representations of our surroundings.
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Affiliation(s)
- Ryan A Wirt
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Adam M McNeela
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - James M Hyman
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV 89154, USA.
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20
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Neuronal Network Excitability in Alzheimer's Disease: The Puzzle of Similar versus Divergent Roles of Amyloid β and Tau. eNeuro 2021; 8:ENEURO.0418-20.2020. [PMID: 33741601 PMCID: PMC8174042 DOI: 10.1523/eneuro.0418-20.2020] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/02/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most frequent neurodegenerative disorder that commonly causes dementia in the elderly. Recent evidence indicates that network abnormalities, including hypersynchrony, altered oscillatory rhythmic activity, interneuron dysfunction, and synaptic depression, may be key mediators of cognitive decline in AD. In this review, we discuss characteristics of neuronal network excitability in AD, and the role of Aβ and tau in the induction of network hyperexcitability. Many patients harboring genetic mutations that lead to increased Aβ production suffer from seizures and epilepsy before the development of plaques. Similarly, pathologic accumulation of hyperphosphorylated tau has been associated with hyperexcitability in the hippocampus. We present common and divergent roles of tau and Aβ on neuronal hyperexcitability in AD, and hypotheses that could serve as a template for future experiments.
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21
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Long X, Tao Y, Chen XC, Deng B, Cai J, Zhang SJ. Getting Lost: Place Cells and Grid Cells in Rodent Models of Alzheimer's Disease. Neurosci Bull 2021; 37:894-897. [PMID: 33811610 DOI: 10.1007/s12264-021-00670-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/26/2020] [Indexed: 12/26/2022] Open
Affiliation(s)
- Xiaoyang Long
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Yuan Tao
- Department of Neurology, Daping Hospital, Army Medical University, Chongqing, China
| | - Xi-Chan Chen
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Bin Deng
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jing Cai
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Sheng-Jia Zhang
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China.
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22
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Functional Alterations in the Olfactory Neuronal Circuit Occur before Hippocampal Plasticity Deficits in the P301S Mouse Model of Tauopathy: Implications for Early Diagnosis and Translational Research in Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21155431. [PMID: 32751531 PMCID: PMC7432464 DOI: 10.3390/ijms21155431] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/18/2020] [Accepted: 07/24/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by neuronal loss and impaired synaptic transmission, ultimately leading to cognitive deficits. Early in the disease, the olfactory track seems most sensitive to tauopathy, while most plasticity studies focused on the hippocampal circuits. Functional network connectivity (FC) and long-term potentiation (LTP), considered as the plasticity substrate of learning and memory, were longitudinally assessed in mice of the P301S model of tauopathy following the course (time and location) of progressively neurodegenerative pathology (i.e., at 3, 6, and 9 months of age) and in their wild type (WT) littermates. Using in vivo local field potential (LFP) recordings, early (at three months) dampening in the gamma oscillatory activity and impairments in the phase-amplitude theta-gamma coupling (PAC) were found in the olfactory bulb (OB) circuit of P301S mice, which were maintained through the whole course of pathology development. In contrast, LFP oscillatory activity and PAC indices were normal in the entorhinal cortex, hippocampal CA1 and CA3 nuclei. Field excitatory postsynaptic potential (fEPSP) recordings from the Shaffer collateral (SC)-CA1 hippocampal stratum pyramidal revealed a significant altered synaptic LTP response to high-frequency stimulation (HFS): at three months of age, no significant difference between genotypes was found in basal synaptic activity, while signs of a deficit in short term plasticity were revealed by alterations in the fEPSPs. At six months of age, a slight deviance was found in basal synaptic activity and significant differences were observed in the LTP response. The alterations in network oscillations at the OB level and impairments in the functioning of the SC-CA1 pyramidal synapses strongly suggest that the progression of tau pathology elicited a brain area, activity-dependent disturbance in functional synaptic transmission. These findings point to early major alterations of neuronal activity in the OB circuit prior to the disturbance of hippocampal synaptic plasticity, possibly involving tauopathy in the anomalous FC. Further research should determine whether those early deficits in the OB network oscillations and FC are possible mechanisms that potentially promote the emergence of hippocampal synaptic impairments during the progression of tauopathy.
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23
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Vyas Y, Montgomery JM, Cheyne JE. Hippocampal Deficits in Amyloid-β-Related Rodent Models of Alzheimer's Disease. Front Neurosci 2020; 14:266. [PMID: 32317913 PMCID: PMC7154147 DOI: 10.3389/fnins.2020.00266] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/09/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is the most common cause of dementia. Symptoms of AD include memory loss, disorientation, mood and behavior changes, confusion, unfounded suspicions, and eventually, difficulty speaking, swallowing, and walking. These symptoms are caused by neuronal degeneration and cell loss that begins in the hippocampus, and later in disease progression spreading to the rest of the brain. While there are some medications that alleviate initial symptoms, there are currently no treatments that stop disease progression. Hippocampal deficits in amyloid-β-related rodent models of AD have revealed synaptic, behavioral and circuit-level defects. These changes in synaptic function, plasticity, neuronal excitability, brain connectivity, and excitation/inhibition imbalance all have profound effects on circuit function, which in turn could exacerbate disease progression. Despite, the wealth of studies on AD pathology we don't yet have a complete understanding of hippocampal deficits in AD. With the increasing development of in vivo recording techniques in awake and freely moving animals, future studies will extend our current knowledge of the mechanisms underpinning how hippocampal function is altered in AD, and aid in progression of treatment strategies that prevent and/or delay AD symptoms.
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Affiliation(s)
| | - Johanna M. Montgomery
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Juliette E. Cheyne
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
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24
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Altered dorsal CA1 neuronal population coding in the APP/PS1 mouse model of Alzheimer's disease. Sci Rep 2020; 10:1077. [PMID: 31974405 PMCID: PMC6978514 DOI: 10.1038/s41598-020-58038-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 01/09/2020] [Indexed: 12/27/2022] Open
Abstract
While the link between amyloid β (Aβ) accumulation and synaptic degradation in Alzheimer’s disease (AD) is known, the consequences of this pathology on population coding remain unknown. We found that the entropy, a measure of the diversity of network firing patterns, was lower in the dorsal CA1 region in the APP/PS1 mouse model of Aβ pathology, relative to controls, thereby reducing the population’s coding capacity. Our results reveal a network level signature of the deficits Aβ accumulation causes to the computations performed by neural circuits.
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25
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Peña-Ortega F. Brain Arrhythmias Induced by Amyloid Beta and Inflammation: Involvement in Alzheimer’s Disease and Other Inflammation-related Pathologies. Curr Alzheimer Res 2020; 16:1108-1131. [DOI: 10.2174/1567205017666191213162233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 10/29/2019] [Accepted: 11/05/2019] [Indexed: 12/13/2022]
Abstract
A variety of neurological diseases, including Alzheimer’s disease (AD), involve amyloid beta (Aβ) accumulation and/or neuroinflammation, which can alter synaptic and neural circuit functions. Consequently, these pathological conditions induce changes in neural network rhythmic activity (brain arrhythmias), which affects many brain functions. Neural network rhythms are involved in information processing, storage and retrieval, which are essential for memory consolidation, executive functioning and sensory processing. Therefore, brain arrhythmias could have catastrophic effects on circuit function, underlying the symptoms of various neurological diseases. Moreover, brain arrhythmias can serve as biomarkers for a variety of brain diseases. The aim of this review is to provide evidence linking Aβ and inflammation to neural network dysfunction, focusing on alterations in brain rhythms and their impact on cognition and sensory processing. I reviewed the most common brain arrhythmias characterized in AD, in AD transgenic models and those induced by Aβ. In addition, I reviewed the modulations of brain rhythms in neuroinflammatory diseases and those induced by immunogens, interleukins and microglia. This review reveals that Aβ and inflammation produce a complex set of effects on neural network function, which are related to the induction of brain arrhythmias and hyperexcitability, both closely related to behavioral alterations. Understanding these brain arrhythmias can help to develop therapeutic strategies to halt or prevent these neural network alterations and treat not only the arrhythmias but also the symptoms of AD and other inflammation-related pathologies.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiologia del Desarrollo y Neurofisiologia, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Qro., 76230, Mexico
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26
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What electrophysiology tells us about Alzheimer's disease: a window into the synchronization and connectivity of brain neurons. Neurobiol Aging 2020; 85:58-73. [DOI: 10.1016/j.neurobiolaging.2019.09.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/27/2019] [Accepted: 09/14/2019] [Indexed: 01/14/2023]
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27
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Ahrens-Nicklas RC, Tecedor L, Hall AF, Lysenko E, Cohen AS, Davidson BL, Marsh ED. Neuronal network dysfunction precedes storage and neurodegeneration in a lysosomal storage disorder. JCI Insight 2019; 4:131961. [PMID: 31573978 PMCID: PMC6948765 DOI: 10.1172/jci.insight.131961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/25/2019] [Indexed: 12/29/2022] Open
Abstract
Accumulation of lysosomal storage material and late-stage neurodegeneration are hallmarks of lysosomal storage disorders (LSDs) affecting the brain. Yet, for most LSDs, including CLN3 disease, the most common form of childhood dementia, it is unclear what mechanisms drive neurologic symptoms. Do deficits arise from loss of function of the mutated protein or toxicity from storage accumulation? Here, using in vitro voltage-sensitive dye imaging and in vivo electrophysiology, we find progressive hippocampal dysfunction occurs before notable lysosomal storage and neuronal loss in 2 CLN3 disease mouse models. Pharmacologic reversal of lysosomal storage deposition in young mice does not rescue this circuit dysfunction. Additionally, we find that CLN3 disease mice lose an electrophysiologic marker of new memory encoding - hippocampal sharp-wave ripples. This discovery, which is also seen in Alzheimer's disease, suggests the possibility of a shared electrophysiologic signature of dementia. Overall, our data describe new insights into previously unknown network-level changes occurring in LSDs affecting the central nervous system and highlight the need for new therapeutic interventions targeting early circuit defects.
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Affiliation(s)
| | | | - Arron F. Hall
- Division of Human Genetics, Department of Pediatrics
| | | | | | | | - Eric D. Marsh
- Division of Child Neurology, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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28
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Ittner A, Ittner LM. Dendritic Tau in Alzheimer's Disease. Neuron 2019; 99:13-27. [PMID: 30001506 DOI: 10.1016/j.neuron.2018.06.003] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/07/2018] [Accepted: 06/01/2018] [Indexed: 01/08/2023]
Abstract
The microtubule-associated protein tau and amyloid-β (Aβ) are key players in Alzheimer's disease (AD). Aβ and tau are linked in a molecular pathway at the post-synapse with tau-dependent synaptic dysfunction being a major pathomechanism in AD. Recent work on site-specific modification of dendritic and more specifically post-synaptic tau has revealed new endogenous functions of tau that limits synaptic Aβ toxicity. Thus, molecular studies opened a new perspective on tau, placing it at the center of neurotoxic and neuroprotective signaling at the post-synapse. Here, we review recent advances on tau in the dendritic compartments, with implications for understanding and treatment of AD and related neurological conditions.
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Affiliation(s)
- Arne Ittner
- Dementia Research Unit, School of Medical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Lars M Ittner
- Dementia Research Unit, School of Medical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia; Neuroscience Research Australia, Sydney, New South Wales 2031, Australia; Dementia Research Centre, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.
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29
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Unsupervised excitation: GABAergic dysfunctions in Alzheimer’s disease. Brain Res 2019; 1707:216-226. [DOI: 10.1016/j.brainres.2018.11.042] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/31/2018] [Accepted: 11/27/2018] [Indexed: 12/22/2022]
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30
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Galloway CR, Ravipati K, Singh S, Lebois EP, Cohen RM, Levey AI, Manns JR. Hippocampal place cell dysfunction and the effects of muscarinic M 1 receptor agonism in a rat model of Alzheimer's disease. Hippocampus 2018; 28:568-585. [PMID: 29742799 DOI: 10.1002/hipo.22961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 04/02/2018] [Accepted: 05/06/2018] [Indexed: 11/09/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that disproportionately impacts memory and the hippocampus. However, it is unclear how AD pathology influences the activity of surviving neurons in the hippocampus to contribute to the memory symptoms in AD. One well-understood connection between spatial memory and neuronal activity in healthy brains is the activity of place cells, neurons in the hippocampus that fire preferentially in a specific location of a given environment (the place field of the place cell). In the present study, place cells were recorded from the hippocampus in a recently-developed rat model of AD (Tg-F344 AD) at an age (12-20 months) at which the AD rats showed marked spatial memory deficits. Place cells in the CA2 and CA3 pyramidal regions of the hippocampus in AD rats showed sharply reduced spatial fidelity relative to wild-type (WT) rats. In contrast, spiking activity of place cells recorded in region CA1 in AD rats showed good spatial fidelity that was similar to CA1 place cells in WT rats. Oral administration of the M1 muscarinic acetylcholine receptor agonist VU0364572 impacted place cell firing rates in CA1 and CA2/3 hippocampal regions, but did not improve the spatial fidelity of CA2/3 hippocampal place cells in AD rats. The results indicated that, to the extent the spatial memory impairment in AD rats was attributable to hippocampal dysfunction, the memory impairment was more attributable to dysfunction in hippocampal regions CA2 and CA3 rather than CA1.
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Affiliation(s)
| | - Kaushik Ravipati
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia
| | - Suyashi Singh
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia
| | - Evan P Lebois
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Robert M Cohen
- Department of Psychiatry, Emory University, Atlanta, Georgia
| | - Allan I Levey
- Department of Neurology, Emory University, Atlanta, Georgia
| | - Joseph R Manns
- Department of Psychology, Emory University, Atlanta, Georgia
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31
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Altered hippocampal replay is associated with memory impairment in mice heterozygous for the Scn2a gene. Nat Neurosci 2018; 21:996-1003. [PMID: 29867081 DOI: 10.1038/s41593-018-0163-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/25/2018] [Indexed: 01/14/2023]
Abstract
An accumulating body of experimental evidence has implicated hippocampal replay occurring within sharp wave ripples (SPW-Rs) as crucial for learning and memory in healthy subjects. This raises speculation that neurological disorders impairing memory disrupt either SPW-Rs or their underlying neuronal activity. We report that mice heterozygous for the gene Scn2a, a site of frequent de novo mutations in humans with intellectual disability, displayed impaired spatial memory. While we observed no changes during encoding, to either single place cells or cell assemblies, we identified abnormalities restricted to SPW-R episodes that manifest as decreased cell assembly reactivation strengths and truncated hippocampal replay sequences. Our results suggest that alterations to hippocampal replay content may underlie disease-associated memory deficits.
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32
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Mondragón-Rodríguez S, Salas-Gallardo A, González-Pereyra P, Macías M, Ordaz B, Peña-Ortega F, Aguilar-Vázquez A, Orta-Salazar E, Díaz-Cintra S, Perry G, Williams S. Phosphorylation of Tau protein correlates with changes in hippocampal theta oscillations and reduces hippocampal excitability in Alzheimer's model. J Biol Chem 2018; 293:8462-8472. [PMID: 29632073 DOI: 10.1074/jbc.ra117.001187] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/14/2018] [Indexed: 01/15/2023] Open
Abstract
Tau hyperphosphorylation at several sites, including those close to the microtubule domain region (MDr), is considered a key pathological event in the development of Alzheimer's disease (AD). Recent studies indicate that at the very early stage of this disease, increased phosphorylation in Tau's MDr domain correlates with reduced levels of neuronal excitability. Mechanistically, we show that pyramidal neurons and some parvalbumin-positive interneurons in 1-month-old triple-transgenic AD mice accumulate hyperphosphorylated Tau protein and that this accumulation correlates with changes in theta oscillations in hippocampal neurons. Pyramidal neurons from young triple-transgenic AD mice exhibited less spike accommodation and power increase in subthreshold membrane oscillations. Furthermore, triple-transgenic AD mice challenged with the potassium channel blocker 4-aminopyridine had reduced theta amplitude compared with 4-aminopyridine-treated control mice and, unlike these controls, displayed no seizure-like activity after this challenge. Collectively, our results provide new insights into AD pathogenesis and suggest that increases in Tau phosphorylation at the initial stages of the disease represent neuronal responses that compensate for brain circuit overexcitation.
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Affiliation(s)
- Siddhartha Mondragón-Rodríguez
- From the CONACYT National Council for Science and Technology, 03940 México, México, .,UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Anahí Salas-Gallardo
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Perla González-Pereyra
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Martín Macías
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Benito Ordaz
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Fernando Peña-Ortega
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Azucena Aguilar-Vázquez
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Erika Orta-Salazar
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - Sofía Díaz-Cintra
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, 76230 Querétaro, México
| | - George Perry
- the UTSA Neuroscience Institute and Department of Biology, College of Sciences, University of Texas at San Antonio, San Antonio, Texas 78249, and
| | - Sylvain Williams
- the Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Quebec H4H 1R3, Canada
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Gamma oscillations in the entorhinal-hippocampal circuit underlying memory and dementia. Neurosci Res 2018; 129:40-46. [PMID: 29438778 DOI: 10.1016/j.neures.2018.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/22/2022]
Abstract
Gamma oscillations that occur within the entorhinal cortex-hippocampal circuitry play important roles in the formation and retrieval of memory in healthy brains. Recent studies report that gamma oscillations are impaired in the entorhinal-hippocampal circuit of Alzheimer's disease (AD) patients and AD animal models. Here we review the latest advancements in studies of entorhinal-hippocampal gamma oscillations in healthy memory and dementia. This review is especially salient for readers in Alzheimer's research field not familiar with in vivo electrophysiology. Recent studies have begun to show a causal link between gamma oscillations and AD pathology, suggesting that gamma oscillations may even offer a plausible future therapeutic target.
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34
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Mably AJ, Gereke BJ, Jones DT, Colgin LL. Impairments in spatial representations and rhythmic coordination of place cells in the 3xTg mouse model of Alzheimer's disease. Hippocampus 2017; 27:378-392. [PMID: 28032686 DOI: 10.1002/hipo.22697] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2016] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is an irreversible and highly progressive neurodegenerative disease. Clinically, patients with AD display impairments in episodic and spatial memory. However, the underlying neuronal dysfunctions that result in these impairments remain poorly understood. The hippocampus is crucial for spatial and episodic memory, and thus we tested the hypothesis that abnormal neuronal representations of space in the hippocampus contribute to memory deficits in AD. To test this hypothesis, we recorded spikes from place cells in hippocampal subfield CA1, together with corresponding rhythmic activity in local field potentials, in the 3xTg AD mouse model. We observed disturbances in place cell firing patterns, many of which were consistent with place cell disturbances reported in other rodent models of AD. We found place cell representations of space to be unstable in 3xTg mice compared to control mice. Furthermore, coordination of place cell firing by hippocampal rhythms was disrupted in 3xTg mice. Specifically, a smaller proportion of place cells from 3xTg mice were significantly phase-locked to theta and slow gamma rhythms, and the theta and slow gamma phases at which spikes occurred were also altered. Remarkably, these disturbances were observed at an age before detectable Aβ pathology had developed. Consistencies between these findings in 3xTg mice and previous findings from other AD models suggest that disturbances in place cell firing and hippocampal rhythms are related to AD rather than reflecting peculiarities inherent to a particular transgenic model. Thus, disturbed rhythmic organization of place cell activity may contribute to unstable spatial representations, and related spatial memory deficits, in AD. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexandra J Mably
- Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, 78712.,Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712
| | - Brian J Gereke
- Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, 78712.,Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, 78712
| | - Dylan T Jones
- Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, 78712.,Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712
| | - Laura Lee Colgin
- Center for Learning and Memory, The University of Texas at Austin, Austin, Texas, 78712.,Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712.,Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, 78712
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35
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Papazoglou A, Soos J, Lundt A, Wormuth C, Ginde VR, Müller R, Henseler C, Broich K, Xie K, Ehninger D, Haenisch B, Weiergräber M. Gender-Specific Hippocampal Dysrhythmia and Aberrant Hippocampal and Cortical Excitability in the APPswePS1dE9 Model of Alzheimer's Disease. Neural Plast 2016; 2016:7167358. [PMID: 27840743 PMCID: PMC5093295 DOI: 10.1155/2016/7167358] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/07/2016] [Accepted: 09/19/2016] [Indexed: 12/26/2022] Open
Abstract
Alzheimer's disease (AD) is a multifactorial disorder leading to progressive memory loss and eventually death. In this study an APPswePS1dE9 AD mouse model has been analyzed using implantable video-EEG radiotelemetry to perform long-term EEG recordings from the primary motor cortex M1 and the hippocampal CA1 region in both genders. Besides motor activity, EEG recordings were analyzed for electroencephalographic seizure activity and frequency characteristics using a Fast Fourier Transformation (FFT) based approach. Automatic seizure detection revealed severe electroencephalographic seizure activity in both M1 and CA1 deflection in APPswePS1dE9 mice with gender-specific characteristics. Frequency analysis of both surface and deep EEG recordings elicited complex age, gender, and activity dependent alterations in the theta and gamma range. Females displayed an antithetic decrease in theta (θ) and increase in gamma (γ) power at 18-19 weeks of age whereas related changes in males occurred earlier at 14 weeks of age. In females, theta (θ) and gamma (γ) power alterations predominated in the inactive state suggesting a reduction in atropine-sensitive type II theta in APPswePS1dE9 animals. Gender-specific central dysrhythmia and network alterations in APPswePS1dE9 point to a functional role in behavioral and cognitive deficits and might serve as early biomarkers for AD in the future.
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Affiliation(s)
- Anna Papazoglou
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
| | - Julien Soos
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)), Bonn, Germany
| | - Andreas Lundt
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
| | - Carola Wormuth
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
| | - Varun Raj Ginde
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)), Bonn, Germany
| | - Ralf Müller
- Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany
| | - Christina Henseler
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
| | - Karl Broich
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
| | - Kan Xie
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)), Bonn, Germany
| | - Dan Ehninger
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)), Bonn, Germany
| | - Britta Haenisch
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)), Bonn, Germany
| | - Marco Weiergräber
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM)), Bonn, Germany
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