1
|
Grella SL, Donaldson TN. Contextual memory engrams, and the neuromodulatory influence of the locus coeruleus. Front Mol Neurosci 2024; 17:1342622. [PMID: 38375501 PMCID: PMC10875109 DOI: 10.3389/fnmol.2024.1342622] [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: 11/22/2023] [Accepted: 01/19/2024] [Indexed: 02/21/2024] Open
Abstract
Here, we review the basis of contextual memory at a conceptual and cellular level. We begin with an overview of the philosophical foundations of traversing space, followed by theories covering the material bases of contextual representations in the hippocampus (engrams), exploring functional characteristics of the cells and subfields within. Next, we explore various methodological approaches for investigating contextual memory engrams, emphasizing plasticity mechanisms. This leads us to discuss the role of neuromodulatory inputs in governing these dynamic changes. We then outline a recent hypothesis involving noradrenergic and dopaminergic projections from the locus coeruleus (LC) to different subregions of the hippocampus, in sculpting contextual representations, giving a brief description of the neuroanatomical and physiological properties of the LC. Finally, we examine how activity in the LC influences contextual memory processes through synaptic plasticity mechanisms to alter hippocampal engrams. Overall, we find that phasic activation of the LC plays an important role in promoting new learning and altering mnemonic processes at the behavioral and cellular level through the neuromodulatory influence of NE/DA in the hippocampus. These findings may provide insight into mechanisms of hippocampal remapping and memory updating, memory processes that are potentially dysregulated in certain psychiatric and neurodegenerative disorders.
Collapse
Affiliation(s)
- Stephanie L. Grella
- MNEME Lab, Department of Psychology, Program in Neuroscience, Loyola University Chicago, Chicago, IL, United States
| | - Tia N. Donaldson
- Systems Neuroscience and Behavior Lab, Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| |
Collapse
|
2
|
Clewett D, McClay M. Emotional arousal lingers in time to bind discrete episodes in memory. Cogn Emot 2024:1-20. [PMID: 38271625 DOI: 10.1080/02699931.2023.2295853] [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: 05/16/2023] [Accepted: 11/21/2023] [Indexed: 01/27/2024]
Abstract
Temporal stability and change in neutral contexts can transform continuous experiences into distinct and memorable events. However, less is known about how shifting emotional states influence these memory processes, despite ample evidence that emotion impacts non-temporal aspects of memory. Here, we examined if emotional stimuli influence temporal memory for recent event sequences. Participants encoded lists of neutral images while listening to auditory tones. At regular intervals within each list, participants heard emotional positive, negative, or neutral sounds, which served as "emotional event boundaries" that divided each sequence into discrete events. Temporal order memory was tested for neutral item pairs that either spanned an emotional sound or were encountered within the same auditory event. Encountering a highly arousing event boundary led to faster response times for items encoded within the next event. Critically, we found that highly arousing sounds had different effects on binding ongoing versus ensuing sequential representations in memory. Specifically, highly arousing sounds were significantly more likely to enhance temporal order memory for ensuing information compared to information that spanned those boundaries, especially for boundaries with negative valence. These findings suggest that within aversive emotional contexts, fluctuations in arousal help shape the temporal organisation of events in memory.
Collapse
Affiliation(s)
- David Clewett
- Department of Psychology, University of California, Los Angeles, CA, USA
| | - Mason McClay
- Department of Psychology, University of California, Los Angeles, CA, USA
| |
Collapse
|
3
|
Larsen LE, Caestecker S, Stevens L, van Mierlo P, Carrette E, Boon P, Vonck K, Raedt R. Hippocampal seizures differentially modulate locus coeruleus activity and result in consistent time-locked release of noradrenaline in rat hippocampus. Neurobiol Dis 2023; 189:106355. [PMID: 37977430 DOI: 10.1016/j.nbd.2023.106355] [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: 09/12/2023] [Revised: 10/29/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023] Open
Abstract
The locus coeruleus (LC) is a small brainstem nucleus and is the sole source of noradrenaline in the neocortex, hippocampus and cerebellum. Noradrenaline is a powerful neuromodulator involved in the regulation of excitability and plasticity of large-scale brain networks. In this study, we performed a detailed assessment of the activity of locus coeruleus neurons and changes in noradrenergic transmission during acute hippocampal seizures evoked with perforant path stimulation, using state-of-the-art methodology. Action potentials of LC neurons, of which some were identified by means of optogenetics, were recorded in anesthetized rats using a multichannel high-density electrophysiology probe. The seizure-induced change in firing rate differed between LC neurons: 55% of neurons decreased in firing rate during seizures, while 28% increased their firing rate. Topographic analysis of multi-unit activity over the electrophysiology probe showed a topographic clustering of neurons that were inhibited or excited during seizures. Changes in hippocampal noradrenaline transmission during seizures were assessed using a fluorescent biosensor for noradrenaline, GRABNE2m, in combination with fiber photometry, in both anesthetized and awake rats. Although our neuronal recordings indicated both inhibition and excitation of LC neurons during seizures, a consistent release of noradrenaline was observed. Concentrations of noradrenaline increased at seizure onset and decreased during or shortly after the seizure. In conclusion, this study showed consistent but heterogeneous modulation of LC neurons and a consistent time-locked release of hippocampal noradrenaline during acute hippocampal seizures.
Collapse
Affiliation(s)
- Lars Emil Larsen
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium; Medical Image and Signal Processing, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
| | - Sielke Caestecker
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium.
| | - Latoya Stevens
- Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Department of Medical Oncology/Laboratory for Molecular and Medical Oncology (LMMO), Brussels, Belgium.
| | - Pieter van Mierlo
- Medical Image and Signal Processing, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
| | - Evelien Carrette
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium.
| | - Paul Boon
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium.
| | - Kristl Vonck
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium.
| | - Robrecht Raedt
- 4BRAIN, Department of Head and Skin, Ghent University, Ghent, Belgium.
| |
Collapse
|
4
|
Traina G, Tuszynski JA. The Neurotransmission Basis of Post-Traumatic Stress Disorders by the Fear Conditioning Paradigm. Int J Mol Sci 2023; 24:16327. [PMID: 38003517 PMCID: PMC10671801 DOI: 10.3390/ijms242216327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 10/30/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
Fear conditioning constitutes the best and most reproducible paradigm to study the neurobiological mechanisms underlying emotions. On the other hand, studies on the synaptic plasticity phenomena underlying fear conditioning present neural circuits enforcing this learning pattern related to post-traumatic stress disorder (PTSD). Notably, in both humans and the rodent model, fear conditioning and context rely on dependent neurocircuitry in the amygdala and prefrontal cortex, cingulate gyrus, and hippocampus. In this review, an overview of the role that classical neurotransmitters play in the contextual conditioning model of fear, and therefore in PTSD, was reported.
Collapse
Affiliation(s)
- Giovanna Traina
- Department of Pharmaceutical Sciences, University of Perugia, Via Romana, 06126 Perugia, Italy
| | - Jack A. Tuszynski
- Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Turin, Italy;
- Department of Data Science and Engineering, The Silesian University of Technology, 44-100 Gliwice, Poland
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, AB T6G 2M9, Canada
| |
Collapse
|
5
|
Borzello M, Ramirez S, Treves A, Lee I, Scharfman H, Stark C, Knierim JJ, Rangel LM. Assessments of dentate gyrus function: discoveries and debates. Nat Rev Neurosci 2023; 24:502-517. [PMID: 37316588 PMCID: PMC10529488 DOI: 10.1038/s41583-023-00710-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
There has been considerable speculation regarding the function of the dentate gyrus (DG) - a subregion of the mammalian hippocampus - in learning and memory. In this Perspective article, we compare leading theories of DG function. We note that these theories all critically rely on the generation of distinct patterns of activity in the region to signal differences between experiences and to reduce interference between memories. However, these theories are divided by the roles they attribute to the DG during learning and recall and by the contributions they ascribe to specific inputs or cell types within the DG. These differences influence the information that the DG is thought to impart to downstream structures. We work towards a holistic view of the role of DG in learning and memory by first developing three critical questions to foster a dialogue between the leading theories. We then evaluate the extent to which previous studies address our questions, highlight remaining areas of conflict, and suggest future experiments to bridge these theories.
Collapse
Affiliation(s)
- Mia Borzello
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | | | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Helen Scharfman
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology and Psychiatry and the Neuroscience Institute, New York University Langone Health, New York, NY, USA
- The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Craig Stark
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, CA, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Lara M Rangel
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
6
|
Shang M, Shen M, Xu R, Du J, Zhang J, OuYang D, Du J, Hu J, Sun Z, Wang B, Han Q, Hu Y, Liu Y, Guan Y, Li J, Guo G, Xing J. Moderate white light exposure enhanced spatial memory retrieval by activating a central amygdala-involved circuit in mice. Commun Biol 2023; 6:414. [PMID: 37059729 PMCID: PMC10104844 DOI: 10.1038/s42003-023-04765-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 03/27/2023] [Indexed: 04/16/2023] Open
Abstract
Light exposure can profoundly affect neurological functions and behaviors. Here, we show that short-term exposure to moderate (400 lux) white light during Y-maze test promoted spatial memory retrieval and induced only mild anxiety in mice. This beneficial effect involves the activation of a circuit including neurons in the central amygdala (CeA), locus coeruleus (LC), and dentate gyrus (DG). Specifically, moderate light activated corticotropin-releasing hormone (CRH) positive (+) CeA neurons and induced the release of corticotropin-releasing factor (CRF) from their axon terminals ending in the LC. CRF then activated tyrosine hydroxylase-expressing LC neurons, which send projections to DG and release norepinephrine (NE). NE activated β-adrenergic receptors on CaMKIIα-expressing DG neurons, ultimately promoting spatial memory retrieval. Our study thus demonstrated a specific light scheme that can promote spatial memory without excessive stress, and unraveled the underlying CeA-LC-DG circuit and associated neurochemical mechanisms.
Collapse
Affiliation(s)
- MengJuan Shang
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - MeiLun Shen
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - RuoTong Xu
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - JingYu Du
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - JiMeng Zhang
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - Ding OuYang
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - JunZe Du
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - JunFeng Hu
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - ZhiChuan Sun
- Department of Neurosurgery, Daxing Hospital, Xi'an, ShaanXi, 710032, China
| | - BingXia Wang
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - Qian Han
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - Yang Hu
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - YiHong Liu
- The Third Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Jing Li
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China
| | - GuoZhen Guo
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China.
- Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China.
| | - JunLing Xing
- Department of Radiation Biology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China.
- Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, Fourth Military Medical University, Xi'an, ShaanXi, 710032, China.
| |
Collapse
|
7
|
Durán E, Pandinelli M, Logothetis NK, Eschenko O. Altered norepinephrine transmission after spatial learning impairs sleep-mediated memory consolidation in rats. Sci Rep 2023; 13:4231. [PMID: 36918712 PMCID: PMC10014950 DOI: 10.1038/s41598-023-31308-1] [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: 10/12/2022] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
The therapeutic use of noradrenergic drugs makes the evaluation of their effects on cognition of high priority. Norepinephrine (NE) is an important neuromodulator for a variety of cognitive processes and may importantly contribute to sleep-mediated memory consolidation. The NE transmission fluctuates with the behavioral and/or brain state and influences associated neural activity. Here, we assessed the effects of altered NE transmission after learning of a hippocampal-dependent task on neural activity and spatial memory in adult male rats. We administered clonidine (0.05 mg/kg, i.p.; n = 12 rats) or propranolol (10 mg/kg, i.p.; n = 11) after each of seven daily learning sessions on an 8-arm radial maze. Compared to the saline group (n = 9), the drug-treated rats showed lower learning rates. To assess the effects of drugs on cortical and hippocampal activity, we recorded prefrontal EEG and local field potentials from the CA1 subfield of the dorsal hippocampus for 2 h after each learning session or drug administration. Both drugs significantly reduced the number of hippocampal ripples for at least 2 h. An EEG-based sleep scoring revealed that clonidine made the sleep onset faster while prolonging quiet wakefulness. Propranolol increased active wakefulness at the expense of non-rapid eye movement (NREM) sleep. Clonidine reduced the occurrence of slow oscillations (SO) and sleep spindles during NREM sleep and altered the temporal coupling between SO and sleep spindles. Thus, pharmacological alteration of NE transmission produced a suboptimal brain state for memory consolidation. Our results suggest that the post-learning NE contributes to the efficiency of hippocampal-cortical communication underlying memory consolidation.
Collapse
Affiliation(s)
- Ernesto Durán
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany
| | - Martina Pandinelli
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany
| | - Nikos K Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany.,International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Institute of Neuroscience (ION), Chinese Academy of Sciences, Shanghai, China.,Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, M13 9PT, UK
| | - Oxana Eschenko
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany.
| |
Collapse
|
8
|
Li ZD, Qiu HJ, Wang XQ, Zhang CC, Zhang YJ. Transcutaneous auricular vagus nerve stimulation in poststroke cognitive impairment: protocol for a randomised controlled trial. BMJ Open 2022; 12:e063803. [PMID: 36198457 PMCID: PMC9535199 DOI: 10.1136/bmjopen-2022-063803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND As one of the most common stroke sequelae, poststroke cognitive impairment significantly impacts 17.6%-83% of survivors, affecting their rehabilitation, daily living and quality of life. Improving cognitive abilities among patients in stroke recovery is therefore critical and urgent. Transcutaneous auricular vagus nerve stimulation (TAVNS) is a non-invasive, safe, cost-effective treatment with great potential for improving the cognitive function of poststroke patients. This clinical research will evaluate the effectiveness, and help elucidate the possible underlying mechanisms, of TAVNS for improving poststroke cognitive function. METHODS AND ANALYSIS A single-centre, parallel-group, allocation concealment, assessor-blinded randomised controlled clinical trial. We will allocate 88 recruited participants to the TAVNS or sham group for an intervention that will run for 8 weeks, 5 days per week with twice daily sessions lasting 30 min each. Blood tests will be performed and questionnaires issued at baseline and 8-week and 12 week follow-ups. Primary outcomes will be changes in cognitive function scores. Secondary outcomes will be changes in activities of daily living, quality of life and serum oxidative stress indicators. ETHICS AND DISSEMINATION The Ethics Committee of the First Affiliated Hospital of Hunan University of Chinese Medicine has approved the protocol (No. HN-LL-YJSLW-2022200). Findings will be published in peer-reviewed academic journals and presented at scientific conferences. TRIAL REGISTRATION NUMBER ChiCTR2200057808.
Collapse
Affiliation(s)
- Zhen-Dong Li
- Department of Nursing, The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China
| | - Hang-Jian Qiu
- School of Nursing, Hunan University of Chinese Medicine, Changsha, Hunan, China
| | - Xiao-Qian Wang
- School of Nursing, Hunan University of Chinese Medicine, Changsha, Hunan, China
| | - Cheng-Cheng Zhang
- Department of Nursing, The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China
| | - Yue-Juan Zhang
- Department of Nursing, The First Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China
| |
Collapse
|
9
|
Vargas-Caballero M, Warming H, Walker R, Holmes C, Cruickshank G, Patel B. Vagus Nerve Stimulation as a Potential Therapy in Early Alzheimer's Disease: A Review. Front Hum Neurosci 2022; 16:866434. [PMID: 35572001 PMCID: PMC9098960 DOI: 10.3389/fnhum.2022.866434] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/06/2022] [Indexed: 12/13/2022] Open
Abstract
Cognitive dysfunction in Alzheimer's disease (AD) is caused by disturbances in neuronal circuits of the brain underpinned by synapse loss, neuronal dysfunction and neuronal death. Amyloid beta and tau protein cause these pathological changes and enhance neuroinflammation, which in turn modifies disease progression and severity. Vagal nerve stimulation (VNS), via activation of the locus coeruleus (LC), results in the release of catecholamines in the hippocampus and neocortex, which can enhance synaptic plasticity and reduce inflammatory signalling. Vagal nerve stimulation has shown promise to enhance cognitive ability in animal models. Research in rodents has shown that VNS can have positive effects on basal synaptic function and synaptic plasticity, tune inflammatory signalling, and limit the accumulation of amyloid plaques. Research in humans with invasive and non-invasive VNS devices has shown promise for the modulation of cognition. However, the direct stimulation of the vagus nerve afforded with the invasive procedure carries surgical risks. In contrast, non-invasive VNS has the potential to be a broadly available therapy to manage cognitive symptoms in early AD, however, the magnitude and specificity of its effects remains to be elucidated, and the non-inferiority of the effects of non-invasive VNS as compared with invasive VNS still needs to be established. Ongoing clinical trials with healthy individuals and patients with early AD will provide valuable information to clarify the potential benefits of non-invasive VNS in cognition and AD. Whether invasive or non-invasive VNS can produce a significant improvement on memory function and whether its effects can modify the progression of AD will require further investigation.
Collapse
Affiliation(s)
| | - Hannah Warming
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Robert Walker
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Clive Holmes
- Memory Assessment and Research Centre, Southern Health Foundation Trust, Southampton, United Kingdom
| | - Garth Cruickshank
- Queen Elizabeth Hospital Birmingham, University of Birmingham, Birmingham, United Kingdom
| | | |
Collapse
|
10
|
Jennen L, Mazereel V, Lecei A, Samaey C, Vancampfort D, van Winkel R. Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans. Rev Neurosci 2022; 33:555-582. [PMID: 35172422 DOI: 10.1515/revneuro-2021-0156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 12/12/2022]
Abstract
Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.
Collapse
Affiliation(s)
- Lise Jennen
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Victor Mazereel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| | - Aleksandra Lecei
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Celine Samaey
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Davy Vancampfort
- University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium.,KU Leuven Department of Rehabilitation Sciences, ON IV Herestraat 49, bus 1510, 3000, Leuven, Belgium
| | - Ruud van Winkel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| |
Collapse
|
11
|
Mertens A, Gadeyne S, Lescrauwaet E, Carrette E, Meurs A, De Herdt V, Dewaele F, Raedt R, Miatton M, Boon P, Vonck K. The potential of invasive and non-invasive vagus nerve stimulation to improve verbal memory performance in epilepsy patients. Sci Rep 2022; 12:1984. [PMID: 35132096 PMCID: PMC8821667 DOI: 10.1038/s41598-022-05842-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 01/11/2022] [Indexed: 12/30/2022] Open
Abstract
It has been demonstrated that acute vagus nerve stimulation (VNS) improves word recognition memory in epilepsy patients. Transcutaneous auricular vagus nerve stimulation (taVNS) has gained interest as a non-invasive alternative to improve cognition. In this prospective randomized cross-over study, we investigated the effect of both invasive VNS and taVNS on verbal memory performance in 15 patients with drug-resistant epilepsy. All patients conducted a word recognition memory paradigm in 3 conditions: VNS ON, VNS OFF and taVNS (3-period 3-treatment cross-over study design). For each condition, patients memorized 21 highlighted words from text paragraphs. Afterwards, the intervention was delivered for 30 s. Immediate recall and delayed recognition scores were obtained for each condition. This memory paradigm was repeated after 6 weeks of VNS therapy in 2 conditions: VNS ON and VNS OFF (2-period 2-treatment cross-over study design). Acute VNS and taVNS did not improve verbal memory performance. Immediate recall and delayed recognition scores were significantly improved after 6 weeks of VNS treatment irrespective of the acute intervention. We can conclude that the previously described positive effects of invasive VNS on verbal memory performance could not be replicated with invasive VNS and taVNS. An improved verbal memory performance was seen after 6 weeks of VNS treatment, suggesting that longer and more repetitive stimulation of the vagal pathway is required to modulate verbal memory performance.Clinical trial registration number: NCT05031208.
Collapse
Affiliation(s)
- Ann Mertens
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium.
| | - Stefanie Gadeyne
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Emma Lescrauwaet
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Evelien Carrette
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Alfred Meurs
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Veerle De Herdt
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Frank Dewaele
- Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium
| | - Robrecht Raedt
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Marijke Miatton
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| | - Paul Boon
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium.,Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Kristl Vonck
- Department of Neurology, 4BRAIN Research Group, Ghent University Hospital, 9000, Ghent, Belgium
| |
Collapse
|
12
|
Sun JB, Cheng C, Tian QQ, Yuan H, Yang XJ, Deng H, Guo XY, Cui YP, Zhang MK, Yin ZX, Wang C, Qin W. Transcutaneous Auricular Vagus Nerve Stimulation Improves Spatial Working Memory in Healthy Young Adults. Front Neurosci 2022; 15:790793. [PMID: 35002607 PMCID: PMC8733384 DOI: 10.3389/fnins.2021.790793] [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] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/18/2021] [Indexed: 01/08/2023] Open
Abstract
Working memory (WM) is one of the core components of higher cognitive functions. There exists debate regarding the extent to which current techniques can enhance human WM capacity. Here, we examined the WM modulation effects of a previously less studied technique, transcutaneous auricular vagus nerve stimulation (taVNS). In experiment 1, a within-subject study, we aimed to investigate whether and which stimulation protocols of taVNS can modulate spatial WM performance in healthy adults. Forty-eight participants performed baseline spatial n-back tasks (1, 3-back) and then received online taVNS, offline taVNS, or sham stimulation before or during (online group) the posttest of spatial n-back tasks in random order. Results showed that offline taVNS could significantly increase hits in spatial 3-back task, whereas no effect was found in online taVNS or sham group. No significant taVNS effects were found on correct rejections or reaction time of accurate trials (aRT) in both online and offline protocols. To replicate the results found in experiment 1 and further investigate the generalization effect of offline taVNS, we carried out experiment 2. Sixty participants were recruited and received offline taVNS or offline earlobe stimulation in random order between baseline and posttests of behavioral tests (spatial/digit 3-back tasks). Results replicated the findings; offline taVNS could improve hits but not correct rejections or aRT in spatial WM performance, which were found in experiment 1. However, there were no significant stimulation effects on digit 3-back task. Overall, the findings suggest that offline taVNS has potential on modulating WM performance.
Collapse
Affiliation(s)
- Jin-Bo Sun
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.,Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Chen Cheng
- Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Qian-Qian Tian
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China
| | - Hang Yuan
- Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Xue-Juan Yang
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.,Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Hui Deng
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.,Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Xiao-Yu Guo
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China
| | - Ya-Peng Cui
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China
| | - Meng-Kai Zhang
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China
| | - Zi-Xin Yin
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China
| | - Cong Wang
- Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| | - Wei Qin
- Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.,Intelligent Non-invasive Neuromodulation Technology and Transformation Joint Laboratory, Xidian University, Xi'an, China
| |
Collapse
|
13
|
Grella SL, Gomes SM, Lackie RE, Renda B, Marrone DF. Norepinephrine as a spatial memory reset signal. Behav Pharmacol 2021; 32:531-548. [PMID: 34417358 DOI: 10.1097/fbp.0000000000000648] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Contextual information is represented in the hippocampus (HPC) partially through the recruitment of distinct neuronal ensembles. It is believed that reactivation of these ensembles underlies memory retrieval processes. Recently, we showed that norepinephrine input from phasic locus coeruleus activation induces hippocampal plasticity resulting in the recruitment of new neurons and disengagement from previously established representations. We hypothesize that norepinephrine may provide a neuromodulatory mnemonic switch signaling the HPC to move from a state of retrieval to encoding in the presence of novelty, and therefore, plays a role in memory updating. Here, we tested whether bilateral dorsal dentate gyrus (dDG) infusions of the β-adrenergic receptor (BAR) agonist isoproterenol (ISO), administered prior to encoding or retrieval, would impair spatial working and reference memory by reverting, the system to encoding (thereby recruiting new neurons) potentially interfering with the retrieval of the previously established spatial ensemble. We also investigated whether dDG infusions of ISO could promote cognitive flexibility by switching the system to encoding when it is adaptive (ie, when new information is presented, eg, reversal learning). We found that intra-dDG infusions of ISO given prior to retrieval caused deficits in working and reference memory which was blocked by pretreatment with the BAR-antagonist, propranolol (PRO). In contrast, ISO administered prior to reversal learning led to improved performance. These data support our hypothesis that norepinephrine serves as a novelty signal to update HPC contextual representations via BAR activation-facilitated recruitment of new neurons. This can be both maladaptive and adaptive depending on the situation.
Collapse
Affiliation(s)
- Stephanie L Grella
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Department of Psychological & Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Sarah M Gomes
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Faculty of Health Sciences, School of Medicine, Queen's University, Kingston
| | - Rachel E Lackie
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Program in Neuroscience, Robarts Research Institute, University of Western Ontario, London
| | - Briana Renda
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada
| | - Diano F Marrone
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- McKnight Brain Institute, University of Arizona, Tucson, Arizona, USA
| |
Collapse
|
14
|
Seo DO, Zhang ET, Piantadosi SC, Marcus DJ, Motard LE, Kan BK, Gomez AM, Nguyen TK, Xia L, Bruchas MR. A locus coeruleus to dentate gyrus noradrenergic circuit modulates aversive contextual processing. Neuron 2021; 109:2116-2130.e6. [PMID: 34081911 PMCID: PMC8754261 DOI: 10.1016/j.neuron.2021.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 01/19/2021] [Accepted: 05/07/2021] [Indexed: 12/26/2022]
Abstract
Dysregulation in contextual processing is believed to affect several forms of psychopathology, such as post-traumatic stress disorder (PTSD). The dentate gyrus (DG), a subregion of the hippocampus, is thought to be an important brain region for disambiguating new experiences from prior experiences. Noradrenergic (NE) neurons in the locus coeruleus (LC) are more tonically active during stressful events and send dense projections to the DG, yet an understanding of their function in DG-dependent contextual discrimination has not been established. Here, we isolate a key function of the LC-NE-DG circuit in contextual aversive generalization using selective manipulations and in vivo single-cell calcium imaging. We report that activation of LC-NE neurons and terminal activity results in contextual generalization. We found that these effects required β-adrenergic-mediated modulation of hilar interneurons to ultimately promote aversive generalization, suggesting that disruption of noradrenergic tone may serve as an important avenue for treating stress-induced disorders.
Collapse
Affiliation(s)
- Dong-Oh Seo
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eric T Zhang
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Sean C Piantadosi
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - David J Marcus
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Laura E Motard
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bryce K Kan
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Adrian M Gomez
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tammy K Nguyen
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Li Xia
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael R Bruchas
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; Departments of Anesthesiology and Pharmacology, University of Washington, Seattle, WA 98195, USA.
| |
Collapse
|
15
|
Kang SS, Ahn EH, Liu X, Bryson M, Miller GW, Weinshenker D, Ye K. ApoE4 inhibition of VMAT2 in the locus coeruleus exacerbates Tau pathology in Alzheimer's disease. Acta Neuropathol 2021; 142:139-158. [PMID: 33895869 DOI: 10.1007/s00401-021-02315-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/08/2021] [Accepted: 04/17/2021] [Indexed: 01/20/2023]
Abstract
ApoE4 enhances Tau neurotoxicity and promotes the early onset of AD. Pretangle Tau in the noradrenergic locus coeruleus (LC) is the earliest detectable AD-like pathology in the human brain. However, a direct relationship between ApoE4 and Tau in the LC has not been identified. Here we show that ApoE4 selectively binds to the vesicular monoamine transporter 2 (VMAT2) and inhibits neurotransmitter uptake. The exclusion of norepinephrine (NE) from synaptic vesicles leads to its oxidation into the toxic metabolite 3,4-dihydroxyphenyl glycolaldehyde (DOPEGAL), which subsequently activates cleavage of Tau at N368 by asparagine endopeptidase (AEP) and triggers LC neurodegeneration. Our data reveal that ApoE4 boosts Tau neurotoxicity via VMAT2 inhibition, reduces hippocampal volume, and induces cognitive dysfunction in an AEP- and Tau N368-dependent manner, while conversely ApoE3 binds Tau and protects it from cleavage. Thus, ApoE4 exacerbates Tau neurotoxicity by increasing VMAT2 vesicle leakage and facilitating AEP-mediated Tau proteolytic cleavage in the LC via DOPEGAL.
Collapse
Affiliation(s)
- Seong Su Kang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael St. Whitehead BLDG Room #141, Atlanta, GA, 30322, USA
| | - Eun Hee Ahn
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael St. Whitehead BLDG Room #141, Atlanta, GA, 30322, USA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael St. Whitehead BLDG Room #141, Atlanta, GA, 30322, USA
| | - Matthew Bryson
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael St. Whitehead BLDG Room #141, Atlanta, GA, 30322, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, USA
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael St. Whitehead BLDG Room #141, Atlanta, GA, 30322, USA.
| |
Collapse
|
16
|
Lu HJ, Lv J. β-adrenergic Receptor Activity in the Hippocampal Dentate Gyrus Participates in Spatial Learning and Memory Impairment in Sleep-deprived Rats. Exp Neurobiol 2021; 30:144-154. [PMID: 33972467 PMCID: PMC8118754 DOI: 10.5607/en20058] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/26/2021] [Accepted: 02/23/2021] [Indexed: 11/19/2022] Open
Abstract
Sleep deprivation (SD) leads to cognitive impairment, especially hippocampus-dependent learning and memory (L&M). The hippocampal dentate gyrus (DG) is the key structure involved in spatial L&M while long-term potentiation (LTP) is an important cellular mechanism responsible for L&M. Physiological and behavioral evidences support the hypothesis that norepinephrine (NE) and β-adrenoceptors (β-AR) may play an important role in regulating L&M, including LTP. However, it is enigmatic how β-AR influences the LTP disruption or memory impairment under SD circumstances. In the present study, the rats were subjected to SD for 18 h per day for 21 consecutive days and cognitive capacity was assessed by the Morris water maze (MWM) test. We examined the extracellular concentration of NE in the DG using in vivo brain microdialysis and HPLC analysis. The amplitudes of field excitatory postsynaptic potential (fEPSP) were subsequently measured in the DG during MWM test in freely moving conscious rats. The extracellular concentrations of NE and fEPSP amplitudes in the DG were significantly increased during MWM test, while these responses were suppressed in SD rats. When fEPSP amplitudes in the DG were measured after local injection of isoproterenol (an agonist of β-AR), SD rats significantly alleviated the fEPSP impairment and rescued deficits of spatial L&M. In addition, the reduced expression of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in SD rats significantly increased by activation of β-AR by isoproterenol in the DG. In conclusion, we propose that β-adrenergic signaling can improve memory impairment in sleep-deficient rats by regulating synaptic efficiency and glutamatergic receptor expression.
Collapse
Affiliation(s)
- Huan-Jun Lu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Jiangsu 226019, China
| | - Jing Lv
- Department of Physiology, Hebei University of Engineering, Hebei 056000, China
| |
Collapse
|
17
|
Rao G, Lee H, Gallagher M, Knierim JJ. Decreased investigatory head scanning during exploration in learning-impaired, aged rats. Neurobiol Aging 2021; 98:1-9. [PMID: 33221571 PMCID: PMC8639103 DOI: 10.1016/j.neurobiolaging.2020.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/23/2020] [Accepted: 10/08/2020] [Indexed: 01/04/2023]
Abstract
"Head scanning" is an investigatory behavior that has been linked to spatial exploration and the one-trial formation or strengthening of place cells in the hippocampus. Previous studies have demonstrated that a subset of aged rats with normal spatial learning performance show head scanning rates during a novel, local-global cue-mismatch manipulation that are similar to those of young rats. However, these aged rats demonstrated different patterns of expression of neural activity markers in brain regions associated with spatial learning, perhaps suggesting neural mechanisms that compensate for age-related brain changes. These prior studies did not investigate the head scanning properties of aged rats that had spatial learning impairments. The present study analyzed head scanning behavior in young, aged-unimpaired, and aged-impaired Long Evans rats. Aged-impaired rats performed the head scan behavior at a lower rate than the young rats. These results suggest that decreased attention to spatial landmarks may be a contributing factor to the spatial learning deficits shown by the aged-impaired rats.
Collapse
Affiliation(s)
- Geeta Rao
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA.
| | - Heekyung Lee
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA; Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|
18
|
Wang FX, Tang RQ, Lv J, Xiao B, Li YS, Jin QH. Norepinephrine in the dentate gyrus is involved in spatial learning and memory alteration induced by chronic restraint stress in aged rats. Neuroreport 2020; 31:1308-1314. [PMID: 33165197 DOI: 10.1097/wnr.0000000000001547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The role of norepinephrine of the hippocampal dentate gyrus in spatial learning and memory alteration induced by chronic restraint stress (CRS, 3 h/day, 6 weeks) was investigated in aged rats. Spatial learning and memory were assessed by the Morris water maze (MWM), and the extracellular concentration of norepinephrine and amplitude of field excitatory postsynaptic potential (fEPSP) were measured in the dentate gyrus during MWM test in freely-moving rats. Next, the involvement of β-adrenoceptors in spatial learning and memory of CRS rats was examined by microinjection of its antagonist (propranolol) into the dentate gyrus. In addition, we observed the expression of brain-derived neurotrophic factor (BDNF) protein and activation of cAMP-response element binding protein (CREB) in the dentate gyrus. Compared with the control group, the basal level of norepinephrine, BDNF expression and CREB activation in the dentate gyrus were increased, and the spatial learning and memory abilities were enhanced in CRS rats. In the control group, the norepinephrine concentration and fEPSP amplitude in the dentate gyrus were increased on the second to fourth days of MWM test, and these responses were significantly enhanced in CRS rats. Furthermore, in CRS rats, propranolol significantly decreased the spatial learning and memory abilities, and attenuated the fEPSP response during MWM test, and the BDNF expression and CREB activation in the dentate gyrus. Our results suggest that norepinephrine activation of β-adrenoceptors in the hippocampal dentate gyrus is involved in spatial learning and memory enhancement induced by CRS in aged rats, in part via modulations of synaptic efficiency and CREB-BDNF signaling pathway.
Collapse
Affiliation(s)
- Fei-Xue Wang
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Ruo-Qi Tang
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Jing Lv
- Department of Physiology, Medical College, Hebei University of Engineering, Handan, Hebei Province, China
| | - Bin Xiao
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Ying-Shun Li
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| | - Qing-Hua Jin
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji, Jilin Province
| |
Collapse
|
19
|
O'Callaghan C, Walpola IC, Shine JM. Neuromodulation of the mind-wandering brain state: the interaction between neuromodulatory tone, sharp wave-ripples and spontaneous thought. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190699. [PMID: 33308063 DOI: 10.1098/rstb.2019.0699] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mind-wandering has become a captivating topic for cognitive neuroscientists. By now, it is reasonably well described in terms of its phenomenology and the large-scale neural networks that support it. However, we know very little about what neurobiological mechanisms trigger a mind-wandering episode and sustain the mind-wandering brain state. Here, we focus on the role of ascending neuromodulatory systems (i.e. acetylcholine, noradrenaline, serotonin and dopamine) in shaping mind-wandering. We advance the hypothesis that the hippocampal sharp wave-ripple (SWR) is a compelling candidate for a brain state that can trigger mind-wandering episodes. This hippocampal rhythm, which occurs spontaneously in quiescent behavioural states, is capable of propagating widespread activity in the default network and is functionally associated with recollective, associative, imagination and simulation processes. The occurrence of the SWR is heavily dependent on hippocampal neuromodulatory tone. We describe how the interplay of neuromodulators may promote the hippocampal SWR and trigger mind-wandering episodes. We then identify the global neuromodulatory signatures that shape the evolution of the mind-wandering brain state. Under our proposed framework, mind-wandering emerges due to the interplay between neuromodulatory systems that influence the transitions between brain states, which either facilitate, or impede, a wandering mind. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
Collapse
Affiliation(s)
- Claire O'Callaghan
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia.,Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Ishan C Walpola
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - James M Shine
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia
| |
Collapse
|
20
|
Vidal B, Droguerre M, Venet L, Zimmer L, Valdebenito M, Mouthon F, Charvériat M. Functional ultrasound imaging to study brain dynamics: Application of pharmaco-fUS to atomoxetine. Neuropharmacology 2020; 179:108273. [DOI: 10.1016/j.neuropharm.2020.108273] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/29/2020] [Accepted: 08/10/2020] [Indexed: 12/20/2022]
|
21
|
Kim JL, Bulthuis NE, Cameron HA. The Effects of Anesthesia on Adult Hippocampal Neurogenesis. Front Neurosci 2020; 14:588356. [PMID: 33192273 PMCID: PMC7643675 DOI: 10.3389/fnins.2020.588356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/22/2020] [Indexed: 01/17/2023] Open
Abstract
In animal studies, prolonged sedation with general anesthetics has resulted in cognitive impairments that can last for days to weeks after exposure. One mechanism by which anesthesia may impair cognition is by decreasing adult hippocampal neurogenesis. Several studies have seen a reduction in cell survival after anesthesia in rodents with most studies focusing on two particularly vulnerable age windows: the neonatal period and old age. However, the extent to which sedation affects neurogenesis in young adults remains unclear. Adult neurogenesis in the dentate gyrus (DG) was analyzed in male and female rats 24 h after a 4-h period of sedation with isoflurane, propofol, midazolam, or dexmedetomidine. Three different cell populations were quantified: cells that were 1 week or 1 month old, labeled with the permanent birthdate markers EdU or BrdU, respectively, and precursor cells, identified by their expression of the endogenous dividing cell marker proliferating cell nuclear antigen (PCNA) at the time of sacrifice. Midazolam and dexmedetomidine reduced cell proliferation in the adult DG in both sexes but had no effect on postmitotic cells. Propofol reduced the number of relatively mature, 28-day old, neurons specifically in female rats and had no effects on younger cells. Isoflurane had no detectable effects on any of the cell populations examined. These findings show no general effect of sedation on adult-born neurons but demonstrate that certain sedatives do have drug-specific and sex-specific effects. The impacts observed on different cell populations predict that any cognitive effects of these sedatives would likely occur at different times, with propofol producing a rapid but short-lived impairment and midazolam and dexmedetomidine altering cognition after a several week delay. Taken together, these studies lend support to the hypothesis that decreased neurogenesis in the young adult DG may mediate the effects of sedation on cognitive function.
Collapse
Affiliation(s)
| | | | - Heather A. Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
22
|
Perez DM. α 1-Adrenergic Receptors in Neurotransmission, Synaptic Plasticity, and Cognition. Front Pharmacol 2020; 11:581098. [PMID: 33117176 PMCID: PMC7553051 DOI: 10.3389/fphar.2020.581098] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
α1-adrenergic receptors are G-Protein Coupled Receptors that are involved in neurotransmission and regulate the sympathetic nervous system through binding and activating the neurotransmitter, norepinephrine, and the neurohormone, epinephrine. There are three α1-adrenergic receptor subtypes (α1A, α1B, α1D) that are known to play various roles in neurotransmission and cognition. They are related to two other adrenergic receptor families that also bind norepinephrine and epinephrine, the β- and α2-, each with three subtypes (β1, β2, β3, α2A, α2B, α2C). Previous studies assessing the roles of α1-adrenergic receptors in neurotransmission and cognition have been inconsistent. This was due to the use of poorly-selective ligands and many of these studies were published before the characterization of the cloned receptor subtypes and the subsequent development of animal models. With the availability of more-selective ligands and the development of animal models, a clearer picture of their role in cognition and neurotransmission can be assessed. In this review, we highlight the significant role that the α1-adrenergic receptor plays in regulating synaptic efficacy, both short and long-term synaptic plasticity, and its regulation of different types of memory. We will also present evidence that the α1-adrenergic receptors, and particularly the α1A-adrenergic receptor subtype, are a potentially good target to treat a wide variety of neurological conditions with diminished cognition.
Collapse
Affiliation(s)
- Dianne M Perez
- The Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, United States
| |
Collapse
|
23
|
Bein O, Reggev N, Maril A. Prior knowledge promotes hippocampal separation but cortical assimilation in the left inferior frontal gyrus. Nat Commun 2020; 11:4590. [PMID: 32929067 PMCID: PMC7490707 DOI: 10.1038/s41467-020-18364-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 08/10/2020] [Indexed: 12/11/2022] Open
Abstract
An adaptive memory system rarely learns information tabula rasa, but rather builds on prior knowledge to facilitate learning. How prior knowledge influences the neural representation of novel associations remains unknown. Here, participants associated pairs of faces in two conditions: a famous, highly familiar face with a novel face or two novel faces while undergoing fMRI. We examine multivoxel activity patterns corresponding to individual faces before and after learning. The activity patterns representing members of famous-novel pairs becomes separated in the hippocampus, that is, more distinct from one another through learning, in striking contrast to paired novel faces that become similar. In the left inferior frontal gyrus, however, prior knowledge leads to integration, and in a specific direction: the representation of the novel face becomes similar to that of the famous face after learning, suggesting assimilation of new into old memories. We propose that hippocampal separation might resolve interference between existing and newly learned information, allowing cortical assimilation. Thus, associative learning with versus without prior knowledge relies on radically different computations. Prior knowledge strongly impacts new learning, but its influence on the neural representation of novel information is unknown. Here, the authors show multiple neural codes for learning: prior knowledge leads to integrated cortical representations, while promoting hippocampal separation.
Collapse
Affiliation(s)
- Oded Bein
- Department of Psychology, New York University, 6 Washington Pl, New York, NY, 10003, USA
| | - Niv Reggev
- Psychology Department, Ben Gurion University of the Negev, 1 Shderot Ben Gurion, Be'er Sheva, 8410501, Israel
| | - Anat Maril
- Department of Psychology, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem, 91905, Israel. .,Department of Cognitive Science, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem, 91905, Israel.
| |
Collapse
|
24
|
Abstract
In the present study we investigated the long-standing question whether and why emotionally arousing memories are more distinct as compared to neutral experiences. We assumed that memory benefits from the distinctiveness of emotional information, and that emotions affect encoding by reducing interference among overlapping memory representations. Since pattern separation is the process which minimizes interference between memory representations with similar features, we examined the behavioral manifestation of putative neural mechanisms enabling pattern separation (i.e. mnemonic discrimination) for emotionally arousing materials using the Mnemonic Similarity Task with negative, positive, and neutral images as stimuli. Immediately after incidental encoding, subjects were presented with stimuli they had seen at encoding and also with new items. Crucially, participants were also presented with lure images that were visually similar to ones they had seen before. Response options were old, new, and similar. Our results showed that individuals were better in discriminating between similar, emotionally arousing memories, when compared to the neutral stimuli. Moreover, this so-called lure discrimination performance was better for the negative images, than it was for the positive stimuli. Finally, we showed that the high arousing negative stimuli were better separated than the low arousing negative stimuli, and a similar pattern of results was found for the positive items. Altogether, these findings suggest that lure discrimination is modulated by arousal and not by valence. We argue that noradrenergic activity might facilitate interference resolution among memory representations with similar features, and that superior pattern separation might play a key role in memory enhancement for emotional experiences.
Collapse
|
25
|
Mertens A, Naert L, Miatton M, Poppa T, Carrette E, Gadeyne S, Raedt R, Boon P, Vonck K. Transcutaneous Vagus Nerve Stimulation Does Not Affect Verbal Memory Performance in Healthy Volunteers. Front Psychol 2020; 11:551. [PMID: 32351421 PMCID: PMC7174665 DOI: 10.3389/fpsyg.2020.00551] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/09/2020] [Indexed: 01/05/2023] Open
Abstract
Introduction Invasive vagus nerve stimulation (VNS) improves word recognition memory in patients with epilepsy. Recent studies with transcutaneous VNS (tVNS) have also shown positive effects on various subdomains of cognitive functioning in healthy volunteers. In this randomized, controlled, crossover study, we investigated the effect of tVNS on a word recognition memory paradigm in healthy volunteers to further investigate the potential of tVNS in the treatment of cognitive disorders. Methods We included 41 healthy participants aged between 18 and 30 years (young age group) and 24 healthy participants aged between 45 and 80 years (older age group). Each participant completed a word recognition memory paradigm during three different conditions: true tVNS, sham, and control. During true tVNS, stimulation was delivered at the cymba conchae. Sham stimulation was delivered by stimulating the earlobe. In the control condition, no stimulation was given. In each condition, participants were asked to remember highlighted words from three test paragraphs. Accuracy scores were calculated for immediate recall after each test paragraph and for delayed recognition at the end of the paradigm. We hypothesized that highlighted words from paragraphs in the true tVNS condition would be more accurately recalled and/or recognized compared to highlighted words from paragraphs in the sham or control condition. Results In this randomized study, tVNS did not affect the accuracy scores for immediate recall or delayed recognition in both age groups. The younger group showed significantly higher accuracy scores than the older group. The accuracy scores improved over time, and the most recently learned words were better recognized. Participants rated true tVNS as significantly more painful; however, pain was not found to affect accuracy scores. Conclusion In this study, tVNS did not affect verbal memory performance in healthy volunteers. Our results could not replicate the positive effects of invasive VNS on word recognition memory in epilepsy patients. Future research with the aim of improving cognitive function should focus on the rational identification of optimized and individualized stimulation settings primarily in patients with cognitive deficits.
Collapse
Affiliation(s)
- Ann Mertens
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Lien Naert
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Marijke Miatton
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Tasha Poppa
- Ghent Experimental Psychiatry (GHEP) Lab, Department of Psychiatry, Ghent University Hospital, Ghent, Belgium.,Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Evelien Carrette
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Stefanie Gadeyne
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Robrecht Raedt
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Paul Boon
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| | - Kristl Vonck
- 4Brain, Department of Neurology, Institute for Neuroscience, Ghent University Hospital, Ghent, Belgium
| |
Collapse
|
26
|
Venner A, Todd WD, Fraigne J, Bowrey H, Eban-Rothschild A, Kaur S, Anaclet C. Newly identified sleep-wake and circadian circuits as potential therapeutic targets. Sleep 2020; 42:5306564. [PMID: 30722061 DOI: 10.1093/sleep/zsz023] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/25/2019] [Indexed: 02/06/2023] Open
Abstract
Optogenetics and chemogenetics are powerful tools, allowing the specific activation or inhibition of targeted neuronal subpopulations. Application of these techniques to sleep and circadian research has resulted in the unveiling of several neuronal populations that are involved in sleep-wake control, and allowed a comprehensive interrogation of the circuitry through which these nodes are coordinated to orchestrate the sleep-wake cycle. In this review, we discuss six recently described sleep-wake and circadian circuits that show promise as therapeutic targets for sleep medicine. The parafacial zone (PZ) and the ventral tegmental area (VTA) are potential druggable targets for the treatment of insomnia. The brainstem circuit underlying rapid eye movement sleep behavior disorder (RBD) offers new possibilities for treating RBD and neurodegenerative synucleinopathies, whereas the parabrachial nucleus, as a nexus linking arousal state control and breathing, is a promising target for developing treatments for sleep apnea. Therapies that act upon the hypothalamic circuitry underlying the circadian regulation of aggression or the photic regulation of arousal and mood pathway carry enormous potential for helping to reduce the socioeconomic burden of neuropsychiatric and neurodegenerative disorders on society. Intriguingly, the development of chemogenetics as a therapeutic strategy is now well underway and such an approach has the capacity to lead to more focused and less invasive therapies for treating sleep-wake disorders and related comorbidities.
Collapse
Affiliation(s)
- Anne Venner
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - William D Todd
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Jimmy Fraigne
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Hannah Bowrey
- Department of Psychiatry, Rutgers Biomedical Health Sciences, Rutgers University, Newark, NJ.,Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
| | | | - Satvinder Kaur
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Christelle Anaclet
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, NeuroNexus Institute, Graduate Program in Neuroscience - Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA
| |
Collapse
|
27
|
Electroacupuncture Ameliorates Acute Myocardial Ischemia: A Potential Role of the Locus Coeruleus. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:4298657. [PMID: 32328129 PMCID: PMC7150682 DOI: 10.1155/2020/4298657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 02/20/2020] [Accepted: 03/06/2020] [Indexed: 01/08/2023]
Abstract
The locus coeruleus (LC) is closely linked with cardiovascular disease. However, whether it mediates the alleviating effect of electroacupuncture (EA) on acute myocardial ischemia (AMI) remains unclear. A rat model of myocardial ischemia was established through occlusion of the left anterior descending coronary artery. Multichannel in vivo recording and other techniques were used to assess neurons in the LC, norepinephrine (NE) and dopamine (DA) levels in central and myocardial tissue, serum levels of inflammatory factors, and cardiac function. After induction of AMI, LC neuron activity increased and the central NE concentrations increased, while those of DA decreased. Moreover, the serum levels of high-sensitivity C-reactive protein (hs-CRP) increased, whereas those of interleukin-10 (IL-10) decreased. However, these effects were reversed by EA. Additionally, LC lesioning affected NE and DA levels in myocardial tissue and weakened the antimyocardial ischemic effect of EA. Collectively, our results indicated that LC is closely related to AMI and plays an important role in the antimyocardial ischemic effect of EA. This mechanism may be related to inhibition of LC neuron activity by EA, which inhibits the release of large amounts of hs-CRP and promotes that of IL-10 in the serum. Besides, after LC lesioning, EA may improve cardiac function by inhibiting the release of large amounts of NE and promoting the release of DA in myocardial tissue.
Collapse
|
28
|
Dentate Gyrus Mossy Cells Share a Role in Pattern Separation with Dentate Granule Cells and Proximal CA3 Pyramidal Cells. J Neurosci 2019; 39:9570-9584. [PMID: 31641051 DOI: 10.1523/jneurosci.0940-19.2019] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 01/04/2023] Open
Abstract
The complementary processes of pattern completion and pattern separation are thought to be essential for successful memory storage and recall. The dentate gyrus (DG) and proximal CA3 (pCA3) regions have been implicated in pattern separation, in part through extracellular recording studies of these areas. However, the DG contains two types of excitatory cells: granule cells of the granule layer and mossy cells of the hilus. Little is known about the firing properties of mossy cells in freely moving animals, and it is unclear how their activity may contribute to the mnemonic functions of the hippocampus. Furthermore, tetrodes in the dentate granule layer and pCA3 pyramidal layer can also record mossy cells, thus introducing ambiguity into the identification of cell types recorded. Using a random forests classifier, we classified cells recorded in DG (Neunuebel and Knierim, 2014) and pCA3 (Lee et al., 2015) of 16 male rats and separately examined the responses of granule cells, mossy cells, and pCA3 pyramidal cells in a local/global cue mismatch task. All three cell types displayed low correlations between the population representations of the rat's position in the standard and cue-mismatch sessions. These results suggest that all three excitatory cell types within the DG/pCA3 circuit may act as a single functional unit to support pattern separation.SIGNIFICANCE STATEMENT Mossy cells in the dentate gyrus (DG) are an integral component of the DG/pCA3 circuit. While the role of granule cells in the circuitry and computations of the hippocampus has been a focus of study for decades, the contributions of mossy cells have been largely overlooked. Recent studies have revealed the spatial firing properties of mossy cells in awake behaving animals, but how the activity of these highly active cells contributes to the mnemonic functions of the DG is uncertain. We separately analyzed mossy cells, granule cells, and pCA3 cells and found that all three cell types respond similarly to a local/global cue mismatch, suggesting that they form a single functional unit supporting pattern separation.
Collapse
|
29
|
Dyer-Reaves K, Goodman AM, Nelson AR, McMahon LL. Alpha1-Adrenergic Receptor Mediated Long-Term Depression at CA3-CA1 Synapses Can Be Induced via Accumulation of Endogenous Norepinephrine and Is Preserved Following Noradrenergic Denervation. Front Synaptic Neurosci 2019; 11:27. [PMID: 31649525 PMCID: PMC6794465 DOI: 10.3389/fnsyn.2019.00027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 09/20/2019] [Indexed: 12/27/2022] Open
Abstract
Locus coeruleus (LC) provides the sole source of noradrenergic (NA) innervation to hippocampus, and it undergoes significant degeneration early in Alzheimer's disease (AD). Norepinephrine (NE) modulates synaptic transmission and plasticity at hippocampal synapses which likely contributes to hippocampus-dependent learning and memory. We previously reported that pharmacological activation of α1 adrenergic receptors (α1ARs) induces long-term depression (LTD) at CA3-CA1 synapses. Here, we investigated whether accumulation of endogenous NE via pharmacological blockade of norepinephrine transporters (NETs) and the NE degradative enzyme, monoamine oxidase (MAO), can induce α1AR LTD, as these inhibitors are used clinically. Further, we sought to determine how degeneration of hippocampal NA innervation, as occurs in AD, impacts α1AR function and α1AR LTD. Bath application of NET and MAO inhibitors in slices from control rats reliably induced α1AR LTD when β adrenergic receptors were inhibited. To induce degeneration of LC-NA innervation, rats were treated with the specific NA neurotoxin DSP-4 and recordings performed 1-3 weeks later when NA axon degeneration had stabilized. Even with 85% loss of hippocampal NA innervation, α1AR LTD was successfully induced using either the α1AR agonist phenylephrine or the combined NET and MAO inhibitors, and importantly, the LTD magnitude was not different from saline-treated control. These data suggest that despite significant decreases in NA input to hippocampus, the mechanisms necessary for the induction of α1AR LTD remain functional. Furthermore, we posit that α1AR activation could be a viable therapeutic target for pharmacological intervention in AD and other diseases involving malfunctions of NA neurotransmission.
Collapse
Affiliation(s)
- Katie Dyer-Reaves
- Department of Cell, Developmental, and Integrative Biology (CDIB), School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Anthoni M. Goodman
- Department of Cell, Developmental, and Integrative Biology (CDIB), School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Psychology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Amy R. Nelson
- Department of Cell, Developmental, and Integrative Biology (CDIB), School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lori L. McMahon
- Department of Cell, Developmental, and Integrative Biology (CDIB), School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
30
|
Bernstein HL, Lu YL, Botterill JJ, Scharfman HE. Novelty and Novel Objects Increase c-Fos Immunoreactivity in Mossy Cells in the Mouse Dentate Gyrus. Neural Plast 2019; 2019:1815371. [PMID: 31534449 PMCID: PMC6732597 DOI: 10.1155/2019/1815371] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/05/2019] [Indexed: 02/06/2023] Open
Abstract
The dentate gyrus (DG) and its primary cell type, the granule cell (GC), are thought to be critical to many cognitive functions. A major neuronal subtype of the DG is the hilar mossy cell (MC). MCs have been considered to play an important role in cognition, but in vivo studies to understand the activity of MCs during cognitive tasks are challenging because the experiments usually involve trauma to the overlying hippocampus or DG, which kills hilar neurons. In addition, restraint typically occurs, and MC activity is reduced by brief restraint stress. Social isolation often occurs and is potentially confounding. Therefore, we used c-fos protein expression to understand when MCs are active in vivo in socially housed adult C57BL/6 mice in their home cage. We focused on c-fos protein expression after animals explored novel objects, based on previous work which showed that MCs express c-fos protein readily in response to a novel housing location. Also, MCs are required for the training component of the novel object location task and novelty-encoding during a food-related task. GluR2/3 was used as a marker of MCs. The results showed that MC c-fos protein is greatly increased after exposure to novel objects, especially in ventral DG. We also found that novel objects produced higher c-fos levels than familiar objects. Interestingly, a small subset of neurons that did not express GluR2/3 also increased c-fos protein after novel object exposure. In contrast, GCs appeared relatively insensitive. The results support a growing appreciation of the role of the DG in novelty detection and novel object recognition, where hilar neurons and especially MCs are very sensitive.
Collapse
Affiliation(s)
- Hannah L. Bernstein
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Yi-Ling Lu
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Justin J. Botterill
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Helen E. Scharfman
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| |
Collapse
|
31
|
Raber J, Arzy S, Bertolus JB, Depue B, Haas HE, Hofmann SG, Kangas M, Kensinger E, Lowry CA, Marusak HA, Minnier J, Mouly AM, Mühlberger A, Norrholm SD, Peltonen K, Pinna G, Rabinak C, Shiban Y, Soreq H, van der Kooij MA, Lowe L, Weingast LT, Yamashita P, Boutros SW. Current understanding of fear learning and memory in humans and animal models and the value of a linguistic approach for analyzing fear learning and memory in humans. Neurosci Biobehav Rev 2019; 105:136-177. [PMID: 30970272 DOI: 10.1016/j.neubiorev.2019.03.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/30/2019] [Accepted: 03/18/2019] [Indexed: 01/04/2023]
Abstract
Fear is an emotion that serves as a driving factor in how organisms move through the world. In this review, we discuss the current understandings of the subjective experience of fear and the related biological processes involved in fear learning and memory. We first provide an overview of fear learning and memory in humans and animal models, encompassing the neurocircuitry and molecular mechanisms, the influence of genetic and environmental factors, and how fear learning paradigms have contributed to treatments for fear-related disorders, such as posttraumatic stress disorder. Current treatments as well as novel strategies, such as targeting the perisynaptic environment and use of virtual reality, are addressed. We review research on the subjective experience of fear and the role of autobiographical memory in fear-related disorders. We also discuss the gaps in our understanding of fear learning and memory, and the degree of consensus in the field. Lastly, the development of linguistic tools for assessments and treatment of fear learning and memory disorders is discussed.
Collapse
Affiliation(s)
- Jacob Raber
- Department of Behavioral Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR, USA; Departments of Neurology and Radiation Medicine, and Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR, USA.
| | - Shahar Arzy
- Department of Medical Neurobiology, Hebrew University, Jerusalem 91904, Israel
| | | | - Brendan Depue
- Departments of Psychological and Brain Sciences and Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, USA
| | - Haley E Haas
- Department of Psychiatry and Behavioral Science, Emory University School of Medicine, Atlanta, GA, USA
| | - Stefan G Hofmann
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | - Maria Kangas
- Department of Psychology, Macquarie University, Sydney, Australia
| | | | - Christopher A Lowry
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO, USA
| | - Hilary A Marusak
- Department of Pharmacy Practice, Wayne State University, Detroit, MI, USA
| | - Jessica Minnier
- School of Public Health, Oregon Health & Science University, Portland, OR, USA
| | - Anne-Marie Mouly
- Lyon Neuroscience Research Center, CNRS-UMR 5292, INSERM U1028, Université Lyon, Lyon, France
| | - Andreas Mühlberger
- Department of Psychology (Clinical Psychology and Psychotherapy), University of Regensburg, Regensburg, Germany; PFH - Private University of Applied Sciences, Department of Psychology (Clinical Psychology and Psychotherapy Research), Göttingen, Germany
| | - Seth Davin Norrholm
- Department of Psychiatry and Behavioral Science, Emory University School of Medicine, Atlanta, GA, USA
| | - Kirsi Peltonen
- Faculty of Social Sciences/Psychology, Tampere University, Tampere, Finland
| | - Graziano Pinna
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - Christine Rabinak
- Department of Pharmacy Practice, Wayne State University, Detroit, MI, USA
| | - Youssef Shiban
- Department of Psychology (Clinical Psychology and Psychotherapy), University of Regensburg, Regensburg, Germany; PFH - Private University of Applied Sciences, Department of Psychology (Clinical Psychology and Psychotherapy Research), Göttingen, Germany
| | - Hermona Soreq
- Department of Biological Chemistry, Edmond and Lily Safra Center of Brain Science and The Institute of Life Sciences, Hebrew University, Jerusalem 91904, Israel
| | - Michael A van der Kooij
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, Universitatsmedizin der Johannes Guttenberg University Medical Center, Mainz, Germany
| | | | - Leah T Weingast
- Department of Psychiatry and Behavioral Science, Emory University School of Medicine, Atlanta, GA, USA
| | - Paula Yamashita
- School of Public Health, Oregon Health & Science University, Portland, OR, USA
| | - Sydney Weber Boutros
- Department of Behavioral Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR, USA
| |
Collapse
|
32
|
Locus Coeruleus Phasic, But Not Tonic, Activation Initiates Global Remapping in a Familiar Environment. J Neurosci 2018; 39:445-455. [PMID: 30478033 DOI: 10.1523/jneurosci.1956-18.2018] [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: 07/31/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022] Open
Abstract
Locus coeruleus (LC) neurons, the source of hippocampal norepinephrine (NE), are activated by novelty and changes in environmental contingencies. Based on the role of monoamines in reconfiguring invertebrate networks, and data from mammalian systems, a network reset hypothesis for the effects of LC activation has been proposed. We used the cellular compartmental analysis of temporal FISH technique based on the cellular distribution of immediate early genes to examine the effect of LC activation and inactivation, on regional hippocampal maps in male rats, when LC activity was manipulated just before placement in a second familiar (A/A) and/or novel environment (A/B). We found that bilateral phasic, but not tonic, activation of LC reset hippocampal maps in the A/A condition, whereas silencing the LC with clonidine before placement in the A/B condition blocked map reset and a familiar map emerged in the dentate gyrus, proximal and distal CA1, and CA3c. However, CA3a and CA3b encoded the novel environment. These results support a role for phasic LC responses in generating novel hippocampal sequences during memory encoding and, potentially, memory updating. The silencing experiments suggest that novel environments may not be recognized as different by dentate gyrus and CA1 without LC input. The functional distinction between phasic and tonic LC activity argues that these parameters are critical for determining network changes. These data are consistent with the hippocampus activating internal network representations to encode novel experiential episodes and suggest LC input is critical for this role.SIGNIFICANCE STATEMENT Burst activation of the broadly projecting novelty signaling system of the locus coeruleus initiates new network representations throughout the hippocampus despite unchanged external environments. Tonic activation does not alter network representations in the same condition. This suggests differences in the temporal parameters of neuromodulator network activation are critical for neuromodulator function. Silencing this novelty signaling system prevented the appearance of new network representations in a novel environment. Instead, familiar representations were expressed in a subset of hippocampal areas, with another subset encoding the novel environment. This "being in two places at once" argues for independent functional regions within the hippocampus. These experiments strengthen the view that internal states are major determinants of the brain's construction of environmental representations.
Collapse
|
33
|
Duszkiewicz AJ, McNamara CG, Takeuchi T, Genzel L. Novelty and Dopaminergic Modulation of Memory Persistence: A Tale of Two Systems. Trends Neurosci 2018; 42:102-114. [PMID: 30455050 PMCID: PMC6352318 DOI: 10.1016/j.tins.2018.10.002] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 11/10/2022]
Abstract
Adaptation to the ever-changing world is critical for survival, and our brains are particularly tuned to remember events that differ from previous experiences. Novel experiences induce dopamine release in the hippocampus, a process which promotes memory persistence. While axons from the ventral tegmental area (VTA) were generally thought to be the exclusive source of hippocampal dopamine, recent studies have demonstrated that noradrenergic neurons in the locus coeruleus (LC) corelease noradrenaline and dopamine in the hippocampus and that their dopamine release boosts memory retention as well. In this opinion article, we propose that the projections originating from the VTA and the LC belong to two distinct systems that enhance memory of novel events. Novel experiences that share some commonality with past ones (‘common novelty’) activate the VTA and promote semantic memory formation via systems memory consolidation. By contrast, experiences that bear only a minimal relationship to past experiences (‘distinct novelty’) activate the LC to trigger strong initial memory consolidation in the hippocampus, resulting in vivid and long-lasting episodic memories. Novelty induces dopamine release in the hippocampus, triggering memory consolidation to boost memory persistence. Two dopaminergic systems (the ventral tegmental area- and locus coeruleus-hippocampus systems) can stabilise memory through novelty-induced dopamine release in the hippocampus. Novel experiences can be viewed as a spectrum, from experiences that, while clearly novel, share some commonality with past experiences (‘common novelty’), to more fundamentally distinct experiences that bear minimal relationships to past experiences (‘distinct novelty’). We propose that events characterised by ‘common novelty’ boost memory retention via activation of the ventral tegmental area-hippocampus system, resulting in initial consolidation followed by systems consolidation to create neocortical, semantic, long-term memories. We further propose that events characterised by ‘distinct novelty’ lead to the boost of detailed hippocampal, episodic, long-term memory via activation of the locus coeruleus-hippocampus system through strong upregulation of the synaptic tagging and capture mechanism.
Collapse
Affiliation(s)
- Adrian J Duszkiewicz
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Colin G McNamara
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Tomonori Takeuchi
- Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic-EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus, Denmark; Department of Biomedicine, Aarhus University, Aarhus, Denmark; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
| | - Lisa Genzel
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University and Radboudumc, Nijmegen, The Netherlands.
| |
Collapse
|
34
|
Ventura-Bort C, Wirkner J, Genheimer H, Wendt J, Hamm AO, Weymar M. Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level: A Pilot Study. Front Hum Neurosci 2018; 12:202. [PMID: 29977196 PMCID: PMC6021745 DOI: 10.3389/fnhum.2018.00202] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 04/30/2018] [Indexed: 11/30/2022] Open
Abstract
Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool.
Collapse
Affiliation(s)
| | - Janine Wirkner
- Department of Psychology, University of Greifswald, Greifswald, Germany
| | - Hannah Genheimer
- Department of Psychology, University of Würzburg, Würzburg, Germany
| | - Julia Wendt
- Department of Psychology, University of Greifswald, Greifswald, Germany
| | - Alfons O. Hamm
- Department of Psychology, University of Greifswald, Greifswald, Germany
| | - Mathias Weymar
- Department of Psychology, University of Potsdam, Potsdam, Germany
| |
Collapse
|
35
|
Bergt A, Urai AE, Donner TH, Schwabe L. Reading memory formation from the eyes. Eur J Neurosci 2018; 47:1525-1533. [PMID: 29862585 DOI: 10.1111/ejn.13984] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/02/2018] [Accepted: 05/29/2018] [Indexed: 11/28/2022]
Abstract
At any time, we are processing thousands of stimuli, but only few of them will be remembered hours or days later. Is there any way to predict which ones? Here, we tested whether the pupil response to ongoing stimuli, an indicator of physiological arousal known to be relevant for memory formation, is a reliable predictor of long-term memory for these stimuli, over at least 1 day. Pupil dilation was tracked while participants performed visual and auditory encoding tasks. Memory was tested immediately after encoding and 24 hr later. Irrespective of the encoding modality, trial-by-trial variations in pupil dilation predicted reliably which stimuli were recalled in the immediate and 24 hr-delayed tests, in particular for emotionally arousing stimuli. These results show that our eyes may provide a window into the formation of long-term memories. Furthermore, our findings underline the important role of central arousal systems in the rapid formation of memories in the brain, possibly by gating synaptic plasticity mechanisms in the neocortex.
Collapse
Affiliation(s)
- Anne Bergt
- Department of Cognitive Psychology, Institute of Psychology, University of Hamburg, Hamburg, Germany
| | - Anne E Urai
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Tobias H Donner
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Lars Schwabe
- Department of Cognitive Psychology, Institute of Psychology, University of Hamburg, Hamburg, Germany
| |
Collapse
|
36
|
Kassab R, Alexandre F. Pattern separation in the hippocampus: distinct circuits under different conditions. Brain Struct Funct 2018; 223:2785-2808. [PMID: 29637298 DOI: 10.1007/s00429-018-1659-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Abstract
Pattern separation is a fundamental hippocampal process thought to be critical for distinguishing similar episodic memories, and has long been recognized as a natural function of the dentate gyrus (DG), supporting autoassociative learning in CA3. Understanding how neural circuits within the DG-CA3 network mediate this process has received much interest, yet the exact mechanisms behind remain elusive. Here, we argue for the case that sparse coding is necessary but not sufficient to ensure efficient separation and, alternatively, propose a possible interaction of distinct circuits which, nevertheless, act in synergy to produce a unitary function of pattern separation. The proposed circuits involve different functional granule-cell populations, a primary population mediates sparsification and provides recurrent excitation to the other populations which are related to additional pattern separation mechanisms with higher degrees of robustness against interference in CA3. A variety of top-down and bottom-up factors, such as motivation, emotion, and pattern similarity, control the selection of circuitry depending on circumstances. According to this framework, a computational model is implemented and tested against model variants in a series of numerical simulations and biological experiments. The results demonstrate that the model combines fast learning, robust pattern separation and high storage capacity. It also accounts for the controversy around the involvement of the DG during memory recall, explains other puzzling findings, and makes predictions that can inform future investigations.
Collapse
Affiliation(s)
- Randa Kassab
- INRIA, Bordeaux Sud-Ouest, Talence, France. .,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France. .,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France.
| | - Frédéric Alexandre
- INRIA, Bordeaux Sud-Ouest, Talence, France.,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France.,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France
| |
Collapse
|
37
|
Giustino TF, Maren S. Noradrenergic Modulation of Fear Conditioning and Extinction. Front Behav Neurosci 2018; 12:43. [PMID: 29593511 PMCID: PMC5859179 DOI: 10.3389/fnbeh.2018.00043] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/26/2018] [Indexed: 12/12/2022] Open
Abstract
The locus coeruleus norepinephrine (LC-NE) system plays a broad role in learning and memory. Here we begin with an overview of the LC-NE system. We then consider how both direct and indirect manipulations of the LC-NE system affect cued and contextual aversive learning and memory. We propose that NE dynamically modulates Pavlovian conditioning and extinction, either promoting or impairing learning aversive processes under different levels of behavioral arousal. We suggest that under high levels of stress (e.g., during/soon after fear conditioning) the locus coeruleus (LC) promotes cued fear learning by enhancing amygdala function while simultaneously blunting prefrontal function. Under low levels of arousal, the LC promotes PFC function to promote downstream inhibition of the amygdala and foster the extinction of cued fear. Thus, LC-NE action on the medial prefrontal cortex (mPFC) might be described by an inverted-U function such that it can either enhance or hinder learning depending on arousal states. In addition, LC-NE seems to be particularly important for the acquisition, consolidation and extinction of contextual fear memories. This may be due to dense adrenoceptor expression in the hippocampus (HPC) which encodes contextual information, and the ability of NE to regulate long-term potentiation (LTP). Moreover, recent work reveals that the diversity of LC-NE functions in aversive learning and memory are mediated by functionally heterogeneous populations of LC neurons that are defined by their projection targets. Hence, LC-NE function in learning and memory is determined by projection-specific neuromodulation that accompanies various states of behavioral arousal.
Collapse
Affiliation(s)
- Thomas F Giustino
- Department of Psychological and Brain Sciences, Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Stephen Maren
- Department of Psychological and Brain Sciences, Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| |
Collapse
|
38
|
α1-Adrenoceptors in the hippocampal dentate gyrus involved in learning-dependent long-term potentiation during active-avoidance learning in rats. Neuroreport 2018; 27:1211-6. [PMID: 27603730 DOI: 10.1097/wnr.0000000000000679] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The hippocampus is the key structure for learning and memory in mammals and long-term potentiation (LTP) is an important cellular mechanism responsible for learning and memory. The influences of norepinephrine (NE) on the modulation of learning and memory, as well as LTP, through β-adrenoceptors are well documented, whereas the role of α1-adrenoceptors in learning-dependent LTP is not yet clear. In the present study, we measured extracellular concentrations of NE in the hippocampal dentate gyrus (DG) region using an in-vivo brain microdialysis and high-performance liquid chromatography techniques during the acquisition and extinction of active-avoidance behavior in freely moving conscious rats. Next, the effects of prazosin (an antagonist of α1-adrenoceptor) and phenylephrine (an agonist of the α1-adrenoceptor) on amplitudes of field excitatory postsynaptic potential were measured in the DG region during the active-avoidance behavior. Our results showed that the extracellular concentration of NE in the DG was significantly increased during the acquisition of active-avoidance behavior and gradually returned to the baseline level following extinction training. A local microinjection of prazosin into the DG significantly accelerated the acquisition of the active-avoidance behavior, whereas a local microinjection of phenylephrine retarded the acquisition of the active-avoidance behavior. Furthermore, in all groups, the changes in field excitatory postsynaptic potential amplitude were accompanied by corresponding changes in active-avoidance behavior. Our results suggest that NE activation of α1-adrenoceptors in the hippocampal DG inhibits active-avoidance learning by modulation of synaptic efficiency in rats.
Collapse
|
39
|
Dual contributions of noradrenaline to behavioural flexibility and motivation. Psychopharmacology (Berl) 2018; 235:2687-2702. [PMID: 29998349 PMCID: PMC6182595 DOI: 10.1007/s00213-018-4963-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/27/2018] [Indexed: 01/06/2023]
Abstract
INTRODUCTION While several theories have highlighted the importance of the noradrenergic system for behavioral flexibility, a number of recent studies have also shown a role for noradrenaline in motivation, particularly in effort processing. Here, we designed a novel sequential cost/benefit decision task to test the causal influence of noradrenaline on these two functions in rhesus monkeys. METHODS We manipulated noradrenaline using clonidine, an alpha-2 noradrenergic receptor agonist, which reduces central noradrenaline levels and examined how this manipulation influenced performance on the task. RESULTS Clonidine had two specific and distinct effects: first, it decreased choice variability, without affecting the cost/benefit trade-off; and second, it reduced force production, without modulating the willingness to work. CONCLUSIONS Together, these results support an overarching role for noradrenaline in facing challenging situations in two complementary ways: by modulating behavioral volatility, which would facilitate adaptation depending on the lability of the environment, and by modulating the mobilization of resources to face immediate challenges.
Collapse
|
40
|
Xiao LY, Wang XR, Yang Y, Yang JW, Cao Y, Ma SM, Li TR, Liu CZ. Applications of Acupuncture Therapy in Modulating Plasticity of Central Nervous System. Neuromodulation 2017; 21:762-776. [PMID: 29111577 DOI: 10.1111/ner.12724] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Acupuncture is widely applied for treatment of various neurological disorders. This manuscript will review the preclinical evidence of acupuncture in mediating neural plasticity, the mechanisms involved. MATERIALS AND METHODS We searched acupuncture, plasticity, and other potential related words at the following sites: PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and VIP information data base. The following keywords were used: acupuncture, electroacupuncture, plasticity, neural plasticity, neuroplasticity, neurogenesis, neuroblast, stem cell, progenitor cell, BrdU, synapse, synapse structure, synaptogenesis, axon, axon regeneration, synaptic plasticity, LTP, LTD, neurotrophin, neurotrophic factor, BDNF, GDNF, VEGF, bFGF, EGF, NT-3, NT-4, NT-5, p75NTR, neurotransmitter, acetylcholine, norepinephrine, noradrenaline, dopamine, monamine. We assessed the effects of acupuncture on plasticity under pathological conditions in this review. RESULTS Relevant references were reviewed and presented to reflect the effects of acupuncture on neural plasticity. The acquired literatures mainly focused on neurogenesis, alterations of synapses, neurotrophins (NTs), and neurotranimitters. Acupuncture methods mentioned in this article include manual acupuncture and electroacupuncture. CONCLUSIONS The cumulative evidences demonstrated that acupuncture could induce neural plasticity in rodents exposed to cerebral ischemia. Neural plasticity mediated by acupuncture in other neural disorders, such as Alzheimer's disease, Parkinson's disease, and depression, were also investigated and there is evidence of positive role of acupuncture induced plasticity in these disorders as well. Mediation of neural plasticity by acupuncture is likely associated with its modulation on NTs and neurotransmitters. The exact mechanisms underlying acupuncture's effects on neural plasticity remain to be elucidated. Neural plasticity may be the potential bridge between acupuncture and the treatment of various neurological diseases.
Collapse
Affiliation(s)
- Ling-Yong Xiao
- Beijing University of Chinese Medicine, Beijing, China.,Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Beijing Key Laboratory of Acupuncture Neuromodulation, Capital Medical University, Beijing, China
| | - Xue-Rui Wang
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Beijing Key Laboratory of Acupuncture Neuromodulation, Capital Medical University, Beijing, China
| | - Ye Yang
- Beijing University of Chinese Medicine, Beijing, China
| | - Jing-Wen Yang
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Beijing Key Laboratory of Acupuncture Neuromodulation, Capital Medical University, Beijing, China
| | - Yan Cao
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Beijing Key Laboratory of Acupuncture Neuromodulation, Capital Medical University, Beijing, China
| | - Si-Ming Ma
- Acupuncture and Moxibustion Department, Beijing Hospital of Traditional Chinese Medicine, Beijing Key Laboratory of Acupuncture Neuromodulation, Capital Medical University, Beijing, China
| | - Tian-Ran Li
- Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Cun-Zhi Liu
- Beijing University of Chinese Medicine, Beijing, China
| |
Collapse
|
41
|
Activation of β-adrenoceptor facilitates active avoidance learning through enhancement of glutamate levels in the hippocampal dentate gyrus. Neuroreport 2017; 28:973-979. [DOI: 10.1097/wnr.0000000000000868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
42
|
Krishnamurthy K, Nassar MR, Sarode S, Gold JI. Arousal-related adjustments of perceptual biases optimize perception in dynamic environments. Nat Hum Behav 2017; 1. [PMID: 29034334 PMCID: PMC5638136 DOI: 10.1038/s41562-017-0107] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Prior expectations can be used to improve perceptual judgments about ambiguous stimuli. However, little is known about if and how these improvements are maintained in dynamic environments in which the quality of appropriate priors changes from one stimulus to the next. Using a sound-localization task, we show that changes in stimulus predictability lead to arousal-mediated adjustments in the magnitude of prior-driven biases that optimize perceptual judgments about each stimulus. These adjustments depend on task-dependent changes in the relevance and reliability of prior expectations, which subjects update using both normative and idiosyncratic principles. The resulting variations in biases across task conditions and individuals are reflected in modulations of pupil diameter, such that larger stimulus-evoked pupil responses correspond to smaller biases. These results suggest a critical role for the arousal system in adjusting the strength of perceptual biases with respect to inferred environmental dynamics to optimize perceptual judgements.
Collapse
Affiliation(s)
| | - Matthew R Nassar
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University 02912
| | - Shilpa Sarode
- Department of Electrical Engineering, University of Pennsylvania 19104-6074
| | - Joshua I Gold
- Department of Neuroscience, University of Pennsylvania 19104-6074
| |
Collapse
|
43
|
Twarkowski H, Manahan-Vaughan D. Loss of Catecholaminergic Neuromodulation of Persistent Forms of Hippocampal Synaptic Plasticity with Increasing Age. Front Synaptic Neurosci 2016; 8:30. [PMID: 27725799 PMCID: PMC5035743 DOI: 10.3389/fnsyn.2016.00030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022] Open
Abstract
Neuromodulation by means of the catecholaminergic system is a key component of motivation-driven learning and behaviorally modulated hippocampal synaptic plasticity. In particular, dopamine acting on D1/D5 receptors and noradrenaline acting on beta-adrenergic receptors exert a very potent regulation of forms of hippocampal synaptic plasticity that last for very long-periods of time (>24 h), and occur in conjunction with novel spatial learning. Antagonism of these receptors not only prevents long-term potentiation (LTP) and long-term depression (LTD), but prevents the memory of the spatial event that, under normal circumstances, leads to the perpetuation of these plasticity forms. Spatial learning behavior that normally comes easily to rats, such as object-place learning and spatial reference learning, becomes increasingly impaired with aging. Middle-aged animals display aging-related deficits of specific, but not all, components of spatial learning, and one possibility is that this initial manifestation of decrements in learning ability that become apparent in middle-age relate to changes in motivation, attention and/or the regulation by neuromodulatory systems of these behavioral states. Here, we compared the regulation by dopaminergic D1/D5 and beta-adrenergic receptors of persistent LTP in young (2-4 month old) and middle-aged (8-14 month old) rats. We observed in young rats, that weak potentiation that typically lasts for ca. 2 h could be strengthened into persistent (>24 h) LTP by pharmacological activation of either D1/D5 or beta-adrenergic receptors. By contrast, no such facilitation occurred in middle-aged rats. This difference was not related to an ostensible learning deficit: a facilitation of weak potentiation into LTP by spatial learning was possible both in young and middle-aged rats. It was also not directly linked to deficits in LTP: strong afferent stimulation resulted in equivalent LTP in both age groups. We postulate that this change in catecholaminergic control of synaptic plasticity that emerges with aging, does not relate to a learning deficit per se, rather it derives from an increase in behavioral thresholds for novelty and motivation that emerge with increasing age that impact, in turn, on learning efficacy.
Collapse
Affiliation(s)
- Hannah Twarkowski
- Department of Neurophysiology, Medical Faculty, Ruhr University BochumBochum, Germany; International Graduate School of Neuroscience, Ruhr University BochumBochum, Germany
| | | |
Collapse
|
44
|
Dopaminergic inputs in the dentate gyrus direct the choice of memory encoding. Proc Natl Acad Sci U S A 2016; 113:E5501-10. [PMID: 27573822 DOI: 10.1073/pnas.1606951113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Rewarding experiences are often well remembered, and such memory formation is known to be dependent on dopamine modulation of the neural substrates engaged in learning and memory; however, it is unknown how and where in the brain dopamine signals bias episodic memory toward preceding rather than subsequent events. Here we found that photostimulation of channelrhodopsin-2-expressing dopaminergic fibers in the dentate gyrus induced a long-term depression of cortical inputs, diminished theta oscillations, and impaired subsequent contextual learning. Computational modeling based on this dopamine modulation indicated an asymmetric association of events occurring before and after reward in memory tasks. In subsequent behavioral experiments, preexposure to a natural reward suppressed hippocampus-dependent memory formation, with an effective time window consistent with the duration of dopamine-induced changes of dentate activity. Overall, our results suggest a mechanism by which dopamine enables the hippocampus to encode memory with reduced interference from subsequent experience.
Collapse
|
45
|
Rajkumar R, Kumar JR, Dawe GS. Priming locus coeruleus noradrenergic modulation of medial perforant path-dentate gyrus synaptic plasticity. Neurobiol Learn Mem 2016; 138:215-225. [PMID: 27400867 DOI: 10.1016/j.nlm.2016.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/30/2016] [Accepted: 07/06/2016] [Indexed: 01/09/2023]
Abstract
Priming phenomenon, in which an earlier exposure to a stimulus or condition alters synaptic plasticity in response to a subsequent stimulus or condition, known as a challenge, is an example of metaplasticity. In this review, we make the case that the locus coeruleus noradrenergic system-medial perforant path-dentate gyrus pathway is a neural ensemble amenable to studying priming-challenge effects on synaptic plasticity. Accumulating evidence points to a tyrosine hydroxylase-dependent priming effect achieved by pharmacological (nicotine and antipsychotics) or physiological (septal theta driving) manipulations of the locus coeruleus noradrenergic system that can facilitate noradrenaline-induced synaptic plasticity in the dentate gyrus of the hippocampus. The evidence suggests the hypothesis that behavioural experiences inducing tyrosine hydroxylase expression in the locus coeruleus may be sufficient to prime this form of metaplasticity. We propose exploring this phenomenon of priming and challenge physiologically, to determine whether behavioural experiences are sufficient to prime the locus coeruleus, enabling subsequent pharmacological or behavioural challenge conditions that increase locus coeruleus firing to release sufficient noradrenaline to induce long-lasting potentiation in the dentate gyrus. Such an approach may contribute to unravelling mechanisms underlying this form of metaplasticity and its importance in stress-related mnemonic processes.
Collapse
Affiliation(s)
- Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Jigna Rajesh Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 117456, Singapore
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 117456, Singapore.
| |
Collapse
|
46
|
Combined immunohistochemical and retrograde tracing reveals little evidence of innervation of the rat dentate gyrus by midbrain dopamine neurons. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s11515-016-1404-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
47
|
Daulatzai MA. Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer’s Disease. Neurotox Res 2016; 30:295-337. [DOI: 10.1007/s12640-016-9643-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/22/2022]
|
48
|
Novitskaya Y, Sara SJ, Logothetis NK, Eschenko O. Ripple-triggered stimulation of the locus coeruleus during post-learning sleep disrupts ripple/spindle coupling and impairs memory consolidation. ACTA ACUST UNITED AC 2016; 23:238-48. [PMID: 27084931 PMCID: PMC4836638 DOI: 10.1101/lm.040923.115] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/28/2016] [Indexed: 11/25/2022]
Abstract
Experience-induced replay of neuronal ensembles occurs during hippocampal high-frequency oscillations, or ripples. Post-learning increase in ripple rate is predictive of memory recall, while ripple disruption impairs learning. Ripples may thus present a fundamental component of a neurophysiological mechanism of memory consolidation. In addition to system-level local and cross-regional interactions, a consolidation mechanism involves stabilization of memory representations at the synaptic level. Synaptic plasticity within experience-activated neuronal networks is facilitated by noradrenaline release from the axon terminals of the locus coeruleus (LC). Here, to better understand interactions between the system and synaptic mechanisms underlying “off-line” consolidation, we examined the effects of ripple-associated LC activation on hippocampal and cortical activity and on spatial memory. Rats were trained on a radial maze; after each daily learning session neural activity was monitored for 1 h via implanted electrode arrays. Immediately following “on-line” detection of ripple, a brief train of electrical pulses (0.05 mA) was applied to LC. Low-frequency (20 Hz) stimulation had no effect on spatial learning, while higher-frequency (100 Hz) trains transiently blocked generation of ripple-associated cortical spindles and caused a reference memory deficit. Suppression of synchronous ripple/spindle events appears to interfere with hippocampal-cortical communication, thereby reducing the efficiency of “off-line” memory consolidation.
Collapse
Affiliation(s)
- Yulia Novitskaya
- Max Planck Institute for Biological Cybernetics, Tubingen 72076, Germany
| | - Susan J Sara
- Center for Integrative Research in Biology, CNRS-UMR7152, Collège de France, Paris 75005, France Department of Child and Adolescent Psychiatry, New York University Medical School, New York, New York 10016, USA
| | - Nikos K Logothetis
- Max Planck Institute for Biological Cybernetics, Tubingen 72076, Germany Centre for Imaging Sciences, Biomedical Imaging Institute, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Oxana Eschenko
- Max Planck Institute for Biological Cybernetics, Tubingen 72076, Germany
| |
Collapse
|
49
|
Hagena H, Hansen N, Manahan-Vaughan D. β-Adrenergic Control of Hippocampal Function: Subserving the Choreography of Synaptic Information Storage and Memory. Cereb Cortex 2016; 26:1349-64. [PMID: 26804338 PMCID: PMC4785955 DOI: 10.1093/cercor/bhv330] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Noradrenaline (NA) is a key neuromodulator for the regulation of behavioral state and cognition. It supports learning by increasing arousal and vigilance, whereby new experiences are “earmarked” for encoding. Within the hippocampus, experience-dependent information storage occurs by means of synaptic plasticity. Furthermore, novel spatial, contextual, or associative learning drives changes in synaptic strength, reflected by the strengthening of long-term potentiation (LTP) or long-term depression (LTD). NA acting on β-adrenergic receptors (β-AR) is a key determinant as to whether new experiences result in persistent hippocampal synaptic plasticity. This can even dictate the direction of change of synaptic strength. The different hippocampal subfields play different roles in encoding components of a spatial representation through LTP and LTD. Strikingly, the sensitivity of synaptic plasticity in these subfields to β-adrenergic control is very distinct (dentate gyrus > CA3 > CA1). Moreover, NA released from the locus coeruleus that acts on β-AR leads to hippocampal LTD and an enhancement of LTD-related memory processing. We propose that NA acting on hippocampal β-AR, that is graded according to the novelty or saliency of the experience, determines the content and persistency of synaptic information storage in the hippocampal subfields and therefore of spatial memories.
Collapse
Affiliation(s)
- Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Niels Hansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | | |
Collapse
|
50
|
Rau T, Ziemniak J, Poulsen D. The neuroprotective potential of low-dose methamphetamine in preclinical models of stroke and traumatic brain injury. Prog Neuropsychopharmacol Biol Psychiatry 2016; 64:231-6. [PMID: 25724762 DOI: 10.1016/j.pnpbp.2015.02.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 01/06/2023]
Abstract
Methamphetamine is a psychostimulant that was initially synthesized in 1920. Since then it has been used to treat attention deficit hyperactive disorder (ADHD), obesity and narcolepsy. However, methamphetamine has also become a major drug of abuse worldwide. Under conditions of abuse, which involve the administration of high repetitive doses, methamphetamine can produce considerable neurotoxic effects. However, recent evidence from our laboratory indicates that low doses of methamphetamine can produce robust neuroprotection when administered within 12h after severe traumatic brain injury (TBI) in rodents. Thus, it appears that methamphetamine under certain circumstances and correct dosing can produce a neuroprotective effect. This review addresses the neuroprotective potential of methamphetamine and focuses on the potential beneficial application for TBI.
Collapse
Affiliation(s)
- Thomas Rau
- Dept. Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT, United States
| | - John Ziemniak
- Gwynedd Pharmaceutical Consulting, Gwynedd Valley, PA, United States
| | - David Poulsen
- Neurosurgery Dept., University at Buffalo, SUNY-School of Medicine and Biomedical Sciences, Buffalo, NY, United States.
| |
Collapse
|