1
|
Abdulmalek S, Connole LM, O'Sullivan NC, Beyna M, Pangalos MN, von Schack D, Ring RH, Murphy KJ. Midkine is upregulated in the hippocampus following both spatial and olfactory reward association learning and enhances memory. J Neurochem 2024; 168:2832-2847. [PMID: 39361112 DOI: 10.1111/jnc.16151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 10/06/2024]
Abstract
Hippocampal neuronal plasticity is a fundamental process underpinning learning and memory formation and requiring elaborate molecular mechanisms that result in the dynamic remodelling of synaptic connectivity. The neurotrophic properties of midkine (Mdk) have been implicated in the development and repair of the nervous system, while Mdk knockout resulted in deficits in the formation of certain types of memory. The role of Mdk in the process of memory-associated neuronal plasticity, however, remains poorly understood. We investigated the learning-induced regulation of Mdk in spatial navigation and association learning using the water maze and the odour reward association learning paradigms, characterising a temporal profile of Mdk protein expression post-learning. Both learning events revealed similar patterns of upregulation of expression of the protein in the rat hippocampal dentate gyrus, which were rapid and transient. Moreover, administration of recombinant Mdk during the endogenous Mdk upregulation following learning enhanced memory in the water maze task revealing a pro-cognitive action of Mdk. We further show that, within the adult hippocampus, Mdk mRNA is predominantly expressed in granular and pyramidal neurons and that hippocampal neuronal Mdk expression is regulated by the canonical plasticity-associated neurotransmitter glutamate. Finally, we confirm that the positive action of Mdk on neurite outgrowth previously noted in cortical and cerebellar neurons extends to hippocampal neurons. Together, our findings suggest a role for Mdk in glutamate-mediated hippocampal neuronal plasticity important for long-term memory consolidation.
Collapse
Affiliation(s)
- Sarah Abdulmalek
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Laura M Connole
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Mercedes Beyna
- Inflammation Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, USA
| | | | - David von Schack
- Inflammation Research Unit, Pfizer Worldwide Research & Development, Cambridge, Massachusetts, USA
| | | | - Keith J Murphy
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| |
Collapse
|
2
|
Concina G, Gurgone A, Boggio EM, Raspanti A, Pizzo R, Morello N, Castroflorio E, Pizzorusso T, Sacchetti B, Giustetto M. Stabilizing Immature Dendritic Spines in the Auditory Cortex: A Key Mechanism for mTORC1-Mediated Enhancement of Long-Term Fear Memories. J Neurosci 2023; 43:8744-8755. [PMID: 37857485 PMCID: PMC10727119 DOI: 10.1523/jneurosci.0204-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 10/21/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) pathway has emerged as a key molecular mechanism underlying memory processes. Although mTOR inhibition is known to block memory processes, it remains elusive whether and how an enhancement of mTOR signaling may improve memory processes. Here we found in male mice that the administration of VO-OHpic, an inhibitor of the phosphatase and tensin homolog (PTEN) that negatively modulates AKT-mTOR pathway, enhanced auditory fear memory for days and weeks, while it left short-term memory unchanged. Memory enhancement was associated with a long-lasting increase in immature-type dendritic spines of pyramidal neurons into the auditory cortex. The persistence of spine remodeling over time arose by the interplay between PTEN inhibition and memory processes, as VO-OHpic induced only a transient immature spine growth in the somatosensory cortex, a region not involved in long-term auditory memory. Both the potentiation of fear memories and increase in immature spines were hampered by rapamycin, a selective inhibitor of mTORC1. These data revealed that memory can be potentiated over time by the administration of a selective PTEN inhibitor. In addition to disclosing new information on the cellular mechanisms underlying long-term memory maintenance, our study provides new insights on the molecular processes that aid enhancing memories over time.SIGNIFICANCE STATEMENT The neuronal mechanisms that may help improve the maintenance of long-term memories are still elusive. The inhibition of mammalian-target of rapamycin (mTOR) signaling shows that this pathway plays a crucial role in synaptic plasticity and memory formation. However, whether its activation may strengthen long-term memory storage is unclear. We assessed the consequences of positive modulation of AKT-mTOR pathway obtained by VO-OHpic administration, a phosphatase and tensin homolog inhibitor, on memory retention and underlying synaptic modifications. We found that mTOR activation greatly enhanced memory maintenance for weeks by producing a long-lasting increase of immature-type dendritic spines in pyramidal neurons of the auditory cortex. These results offer new insights on the cellular and molecular mechanisms that can aid enhancing memories over time.
Collapse
Affiliation(s)
- Giulia Concina
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Antonia Gurgone
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Elena M Boggio
- Institute of Neuroscience, National Research Council, Pisa, 56124, Italy
| | | | - Riccardo Pizzo
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Noemi Morello
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | | | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council, Pisa, 56124, Italy
- Scuola Normale Superiore, Biology Laboratory BIO@SNS, Pisa, 56124, Italy
| | | | | |
Collapse
|
3
|
Sepahvand T, Power KD, Qin T, Yuan Q. The Basolateral Amygdala: The Core of a Network for Threat Conditioning, Extinction, and Second-Order Threat Conditioning. BIOLOGY 2023; 12:1274. [PMID: 37886984 PMCID: PMC10604397 DOI: 10.3390/biology12101274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/14/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
Threat conditioning, extinction, and second-order threat conditioning studied in animal models provide insight into the brain-based mechanisms of fear- and anxiety-related disorders and their treatment. Much attention has been paid to the role of the basolateral amygdala (BLA) in such processes, an overview of which is presented in this review. More recent evidence suggests that the BLA serves as the core of a greater network of structures in these forms of learning, including associative and sensory cortices. The BLA is importantly regulated by hippocampal and prefrontal inputs, as well as by the catecholaminergic neuromodulators, norepinephrine and dopamine, that may provide important prediction-error or learning signals for these forms of learning. The sensory cortices may be required for the long-term storage of threat memories. As such, future research may further investigate the potential of the sensory cortices for the long-term storage of extinction and second-order conditioning memories.
Collapse
Affiliation(s)
| | | | | | - Qi Yuan
- Biomedical Sciences, Faculty of Medicine, Memorial University, St John’s, NL A1B 3V6, Canada; (T.S.); (K.D.P.); (T.Q.)
| |
Collapse
|
4
|
Malakasis N, Chavlis S, Poirazi P. Synaptic turnover promotes efficient learning in bio-realistic spiking neural networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541722. [PMID: 37292929 PMCID: PMC10245885 DOI: 10.1101/2023.05.22.541722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
While artificial machine learning systems achieve superhuman performance in specific tasks such as language processing, image and video recognition, they do so use extremely large datasets and huge amounts of power. On the other hand, the brain remains superior in several cognitively challenging tasks while operating with the energy of a small lightbulb. We use a biologically constrained spiking neural network model to explore how the neural tissue achieves such high efficiency and assess its learning capacity on discrimination tasks. We found that synaptic turnover, a form of structural plasticity, which is the ability of the brain to form and eliminate synapses continuously, increases both the speed and the performance of our network on all tasks tested. Moreover, it allows accurate learning using a smaller number of examples. Importantly, these improvements are most significant under conditions of resource scarcity, such as when the number of trainable parameters is halved and when the task difficulty is increased. Our findings provide new insights into the mechanisms that underlie efficient learning in the brain and can inspire the development of more efficient and flexible machine learning algorithms.
Collapse
Affiliation(s)
- Nikos Malakasis
- School of Medicine, University of Crete, Heraklion 70013, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Spyridon Chavlis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| |
Collapse
|
5
|
Lee C, Lee BH, Jung H, Lee C, Sung Y, Kim H, Kim J, Shim JY, Kim JI, Choi DI, Park HY, Kaang BK. Hippocampal engram networks for fear memory recruit new synapses and modify pre-existing synapses in vivo. Curr Biol 2023; 33:507-516.e3. [PMID: 36638799 DOI: 10.1016/j.cub.2022.12.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 01/14/2023]
Abstract
As basic units of neural networks, ensembles of synapses underlie cognitive functions such as learning and memory. These synaptic engrams show elevated synaptic density among engram cells following contextual fear memory formation. Subsequent analysis of the CA3-CA1 engram synapse revealed larger spine sizes, as the synaptic connectivity correlated with the memory strength. Here, we elucidate the synapse dynamics between CA3 and CA1 by tracking identical synapses at multiple time points by adapting two-photon microscopy and dual-eGRASP technique in vivo. After memory formation, synaptic connections between engram populations are enhanced in conjunction with synaptogenesis within the hippocampal network. However, extinction learning specifically correlated with the disappearance of CA3 engram to CA1 engram (E-E) synapses. We observed "newly formed" synapses near pre-existing synapses, which clustered CA3-CA1 engram synapses after fear memory formation. Overall, we conclude that dynamics at CA3 to CA1 E-E synapses are key sites for modification during fear memory states.
Collapse
Affiliation(s)
- Chaery Lee
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Byung Hun Lee
- Department of Physics and Astronomy, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hyunsu Jung
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea; Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, South Korea
| | - Chiwoo Lee
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, South Korea
| | - Yongmin Sung
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hyopil Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Jooyoung Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Jae Youn Shim
- Department of Physics and Astronomy, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Ji-Il Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Dong Il Choi
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hye Yoon Park
- Department of Physics and Astronomy, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea; Department of Electrical and Computer Engineering, College of Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea; Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, South Korea.
| |
Collapse
|
6
|
Xu Z, Geron E, Pérez-Cuesta LM, Bai Y, Gan WB. Generalized extinction of fear memory depends on co-allocation of synaptic plasticity in dendrites. Nat Commun 2023; 14:503. [PMID: 36720872 PMCID: PMC9889816 DOI: 10.1038/s41467-023-35805-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 01/03/2023] [Indexed: 02/02/2023] Open
Abstract
Memories can be modified by new experience in a specific or generalized manner. Changes in synaptic connections are crucial for memory storage, but it remains unknown how synaptic changes associated with different memories are distributed within neuronal circuits and how such distributions affect specific or generalized modification by novel experience. Here we show that fear conditioning with two different auditory stimuli (CS) and footshocks (US) induces dendritic spine elimination mainly on different dendritic branches of layer 5 pyramidal neurons in the mouse motor cortex. Subsequent fear extinction causes CS-specific spine formation and extinction of freezing behavior. In contrast, spine elimination induced by fear conditioning with >2 different CS-USs often co-exists on the same dendritic branches. Fear extinction induces CS-nonspecific spine formation and generalized fear extinction. Moreover, activation of somatostatin-expressing interneurons increases the occurrence of spine elimination induced by different CS-USs on the same dendritic branches and facilitates the generalization of fear extinction. These findings suggest that specific or generalized modification of existing memories by new experience depends on whether synaptic changes induced by previous experiences are segregated or co-exist at the level of individual dendritic branches.
Collapse
Affiliation(s)
- Zhiwei Xu
- Institute of Neurological and Psychiatric Disorders, Shenzhen Bay Laboratory, Shenzhen, 518132, China
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Erez Geron
- Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Luis M Pérez-Cuesta
- Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Yang Bai
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Wen-Biao Gan
- Institute of Neurological and Psychiatric Disorders, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
| |
Collapse
|
7
|
Khan R, Kulasiri D, Samarasinghe S. A multifarious exploration of synaptic tagging and capture hypothesis in synaptic plasticity: Development of an integrated mathematical model and computational experiments. J Theor Biol 2023; 556:111326. [PMID: 36279957 DOI: 10.1016/j.jtbi.2022.111326] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/25/2022] [Accepted: 10/11/2022] [Indexed: 11/17/2022]
Abstract
The synaptic tagging and capture (STC) hypothesis not only explain the integration and association of synaptic activities, but also the formation of learning and memory. The synaptic pathways involved in the synaptic tagging and capture phenomenon are called STC pathways. The STC hypothesis provides a potential explanation of the neuronal and synaptic processes underlying the synaptic consolidation of memories. Several mechanisms and molecules have been proposed to explain the process of memory allocation and synaptic tags, respectively. However, a clear link between the STC hypothesis and memory allocation is still missing because the encoding of memories in neural circuits is mainly associated with strongly recurrently connected groups of neurons. To explore the mechanisms of potential synaptic tagging candidates and their involvement in the process of memory allocation, we develop a mathematical model for a single dendritic spine based on five essential criteria of a synaptic tag. By developing a mathematical model, we attempt to understand the roles of the potentially critical molecular networks underlying the STC and the essential attributes of a synaptic tag. We include essential memory molecules in the STC model that have been identified in earlier studies as crucial for STC pathways. CaMKII activation is critical for the setting of the initial tag; however, coordinated activities with other kinases and the biochemical pathways are necessary for the tag to be stable. PKA modulates NMDAR-mediated Ca2+ signalling. Similarly, PKA and ERK crosstalk is essential for Ca2+ - mediated protein synthesis during l-LTP. Our theoretical model explains the quantitative contribution of Tags and protein synthesis during l-LTP in synaptic strength.
Collapse
Affiliation(s)
- Raheel Khan
- Centre for Advanced Computational Solutions (C-fACS), Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand
| | - D Kulasiri
- Centre for Advanced Computational Solutions (C-fACS), Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand.
| | - S Samarasinghe
- Centre for Advanced Computational Solutions (C-fACS), Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand
| |
Collapse
|
8
|
Chambers AR, Aschauer DF, Eppler JB, Kaschube M, Rumpel S. A stable sensory map emerges from a dynamic equilibrium of neurons with unstable tuning properties. Cereb Cortex 2022; 33:5597-5612. [PMID: 36418925 PMCID: PMC10152095 DOI: 10.1093/cercor/bhac445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 10/17/2022] [Accepted: 10/21/2022] [Indexed: 11/25/2022] Open
Abstract
Abstract
Recent long-term measurements of neuronal activity have revealed that, despite stability in large-scale topographic maps, the tuning properties of individual cortical neurons can undergo substantial reformatting over days. To shed light on this apparent contradiction, we captured the sound response dynamics of auditory cortical neurons using repeated 2-photon calcium imaging in awake mice. We measured sound-evoked responses to a set of pure tone and complex sound stimuli in more than 20,000 auditory cortex neurons over several days. We found that a substantial fraction of neurons dropped in and out of the population response. We modeled these dynamics as a simple discrete-time Markov chain, capturing the continuous changes in responsiveness observed during stable behavioral and environmental conditions. Although only a minority of neurons were driven by the sound stimuli at a given time point, the model predicts that most cells would at least transiently become responsive within 100 days. We observe that, despite single-neuron volatility, the population-level representation of sound frequency was stably maintained, demonstrating the dynamic equilibrium underlying the tonotopic map. Our results show that sensory maps are maintained by shifting subpopulations of neurons “sharing” the job of creating a sensory representation.
Collapse
Affiliation(s)
- Anna R Chambers
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes Gutenberg University Mainz , Duesbergweg 6, Mainz 55128 , Germany
| | - Dominik F Aschauer
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes Gutenberg University Mainz , Duesbergweg 6, Mainz 55128 , Germany
| | - Jens-Bastian Eppler
- Frankfurt Institute for Advanced Studies and Department of Computer Science, Goethe University Frankfurt , Ruth-Moufang-Straße 1, Frankfurt am Main 60438 , Germany
| | - Matthias Kaschube
- Frankfurt Institute for Advanced Studies and Department of Computer Science, Goethe University Frankfurt , Ruth-Moufang-Straße 1, Frankfurt am Main 60438 , Germany
| | - Simon Rumpel
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes Gutenberg University Mainz , Duesbergweg 6, Mainz 55128 , Germany
| |
Collapse
|
9
|
Cranial irradiation induces cognitive decline associated with altered dendritic spine morphology in the young rat hippocampus. Childs Nerv Syst 2022; 38:1867-1875. [PMID: 35962792 DOI: 10.1007/s00381-022-05646-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 08/05/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Therapeutic irradiation is commonly used to treat brain cancers but can induce cognitive dysfunction, especially in children. The mechanism is unknown but likely involves alterations in dendritic spine number and structure. METHODS To explore the impact of radiation exposure on the alteration of dendritic spine morphology in the hippocampus of young brains, 21-day-old Sprague-Dawley rats received cranial irradiation (10 Gy), and changes in spine density and morphology in dentate gyrus (DG) granules and CA1 pyramidal neurons were detected 1 and 3 months later by using Golgi staining. Moreover, we analyzed synapse-associated proteins within dendritic spines after irradiation. RESULT Our data showed that cognitive deficits were detected in young rats at both time points postirradiation, accompanied by morphological changes in dendritic spines. Our results revealed significant reductions in spine density in the DG at both 1 month (40.58%) and 3 months (28.92%) postirradiation. However, there was a decrease in spine density only at 1 month (33.29%) postirradiation in the basal dendrites of CA1 neurons and no significant changes in the apical dendrites of CA1 neurons at either time point. Notably, among our findings were the significant dynamic changes in spine morphology that persisted 3 months following cranial irradiation. Meanwhile, we found that depletion of the synapse-associated proteins PSD95 and Drebrin coincided with alterations in dendritic spines. CONCLUSION These data suggest that the decreased levels of PSD95 and Drebrin after ionizing radiation may cause changes in synaptic plasticity by affecting the morphological structure of dendritic spines, blocking the functional connectivity pathways of the brain and leading to cognitive impairment. Although the mechanism involved is unclear, understanding how ionizing radiation affects young brain hippocampal tissue may be useful to gain new mechanistic insights into radiation-induced cognitive dysfunction.
Collapse
|
10
|
Liu J, Qi J, Chen X, Li Z, Hong B, Ma H, Li G, Shen L, Liu D, Kong Y, Zhai H, Xie Q, Han H, Yang Y. Fear memory-associated synaptic and mitochondrial changes revealed by deep learning-based processing of electron microscopy data. Cell Rep 2022; 40:111151. [PMID: 35926462 DOI: 10.1016/j.celrep.2022.111151] [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: 09/29/2021] [Revised: 05/20/2022] [Accepted: 07/11/2022] [Indexed: 11/03/2022] Open
Abstract
Serial section electron microscopy (ssEM) can provide comprehensive 3D ultrastructural information of the brain with exceptional computational cost. Targeted reconstruction of subcellular structures from ssEM datasets is less computationally demanding but still highly informative. We thus developed a region-CNN-based deep learning method to identify, segment, and reconstruct synapses and mitochondria to explore the structural plasticity of synapses and mitochondria in the auditory cortex of mice subjected to fear conditioning. Upon reconstructing over 135,000 mitochondria and 160,000 synapses, we find that fear conditioning significantly increases the number of mitochondria but decreases their size and promotes formation of multi-contact synapses, comprising a single axonal bouton and multiple postsynaptic sites from different dendrites. Modeling indicates that such multi-contact configuration increases the information storage capacity of new synapses by over 50%. With high accuracy and speed in reconstruction, our method yields structural and functional insight into cellular plasticity associated with fear learning.
Collapse
Affiliation(s)
- Jing Liu
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Junqian Qi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xi Chen
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhenchen Li
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Bei Hong
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Hongtu Ma
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Guoqing Li
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Lijun Shen
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Danqian Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Kong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hao Zhai
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Qiwei Xie
- Research Base of Beijing Modern Manufacturing Development, Beijing University of Technology, Beijing 100124, China.
| | - Hua Han
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| |
Collapse
|
11
|
Ojala KE, Staib M, Gerster S, Ruff CC, Bach DR. Inhibiting Human Aversive Memory by Transcranial Theta-Burst Stimulation to the Primary Sensory Cortex. Biol Psychiatry 2022; 92:149-157. [PMID: 35410762 DOI: 10.1016/j.biopsych.2022.01.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 01/14/2022] [Accepted: 01/26/2022] [Indexed: 12/17/2022]
Abstract
BACKGROUND Predicting adverse events from past experience is fundamental for many biological organisms. However, some individuals suffer from maladaptive memories that impair behavioral control and well-being, e.g., after psychological trauma. Inhibiting the formation and maintenance of such memories would have high clinical relevance. Previous preclinical research has focused on systemically administered pharmacological interventions, which cannot be targeted to specific neural circuits in humans. Here, we investigated the potential of noninvasive neural stimulation on the human sensory cortex in inhibiting aversive memory in a laboratory threat conditioning model. METHODS We build on an emerging nonhuman literature suggesting that primary sensory cortices may be crucially required for threat memory formation and consolidation. Immediately before conditioning innocuous somatosensory stimuli (conditioned stimuli [CS]) to aversive electric stimulation, healthy human participants received continuous theta-burst transcranial magnetic stimulation (cTBS) to individually localized primary somatosensory cortex in either the CS-contralateral (experimental) or CS-ipsilateral (control) hemisphere. We measured fear-potentiated startle to infer threat memory retention on the next day, as well as skin conductance and pupil size during learning. RESULTS After overnight consolidation, threat memory was attenuated in the experimental group compared with the control cTBS group. There was no evidence that this differed between simple and complex CS or that CS identification or initial learning were affected by cTBS. CONCLUSIONS Our results suggest that cTBS to the primary sensory cortex inhibits threat memory, likely by an impact on postlearning consolidation. We propose that noninvasive targeted stimulation of the sensory cortex may provide a new avenue for interfering with aversive memories in humans.
Collapse
Affiliation(s)
- Karita E Ojala
- Computational Psychiatry Research, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland; Neuroscience Centre Zurich, University of Zürich, Zürich, Switzerland.
| | - Matthias Staib
- Computational Psychiatry Research, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland; Neuroscience Centre Zurich, University of Zürich, Zürich, Switzerland
| | - Samuel Gerster
- Computational Psychiatry Research, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland
| | - Christian C Ruff
- Neuroscience Centre Zurich, University of Zürich, Zürich, Switzerland; Zurich Center for Neuroeconomics, Department of Economics, University of Zürich, Zürich, Switzerland
| | - Dominik R Bach
- Computational Psychiatry Research, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zürich, Zürich, Switzerland; Neuroscience Centre Zurich, University of Zürich, Zürich, Switzerland; Wellcome Centre for Human Neuroimaging and Max-Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, London, United Kingdom.
| |
Collapse
|
12
|
Olivo G, Lövdén M, Manzouri A, Terlau L, Jenner B, Jafari A, Petersson S, Li TQ, Fischer H, Månsson KNT. Estimated Gray Matter Volume Rapidly Changes after a Short Motor Task. Cereb Cortex 2022; 32:4356-4369. [PMID: 35136959 PMCID: PMC9528898 DOI: 10.1093/cercor/bhab488] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 11/14/2022] Open
Abstract
Skill learning induces changes in estimates of gray matter volume (GMV) in the human brain, commonly detectable with magnetic resonance imaging (MRI). Rapid changes in GMV estimates while executing tasks may however confound between- and within-subject differences. Fluctuations in arterial blood flow are proposed to underlie this apparent task-related tissue plasticity. To test this hypothesis, we acquired multiple repetitions of structural T1-weighted and functional blood-oxygen level-dependent (BOLD) MRI measurements from 51 subjects performing a finger-tapping task (FTT; á 2 min) repeatedly for 30-60 min. Estimated GMV was decreased in motor regions during FTT compared with rest. Motor-related BOLD signal changes did not overlap nor correlate with GMV changes. Nearly simultaneous BOLD signals cannot fully explain task-induced changes in T1-weighted images. These sensitive and behavior-related GMV changes pose serious questions to reproducibility across studies, and morphological investigations during skill learning can also open new avenues on how to study rapid brain plasticity.
Collapse
Affiliation(s)
- Gaia Olivo
- Department of Psychology, University of Gothenburg, SE-40530, Gothenburg, Sweden.,Aging Research Center (ARC), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, SE-17177, Stockholm, Sweden
| | - Martin Lövdén
- Department of Psychology, University of Gothenburg, SE-40530, Gothenburg, Sweden.,Aging Research Center (ARC), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, SE-17177, Stockholm, Sweden
| | - Amirhossein Manzouri
- Department of Psychology, Stockholm University, SE-10691, Stockholm, Sweden.,Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, SE-11364, Stockholm, Sweden
| | - Laura Terlau
- Center for Lifespan Psychology, Max Planck Institute for Human Development, D-14195, Berlin, Germany.,Max Planck UCL Centre for Computational Psychiatry and Ageing Research, D-14195, Berlin, London
| | - Bo Jenner
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, SE-11364, Stockholm, Sweden
| | - Arian Jafari
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, SE-11364, Stockholm, Sweden
| | - Sven Petersson
- Department of Medical Radiation and Nuclear Medicine, Karolinska University Hospital, Huddinge S-14186, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, SE-14152, Stockholm, Sweden
| | - Tie-Qiang Li
- Department of Medical Radiation and Nuclear Medicine, Karolinska University Hospital, Huddinge S-14186, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, SE-14152, Stockholm, Sweden
| | - Håkan Fischer
- Department of Psychology, Stockholm University, SE-10691, Stockholm, Sweden.,Stockholm University Brain Imaging Centre, SE-10691, Stockholm, Sweden
| | - Kristoffer N T Månsson
- Department of Psychology, Stockholm University, SE-10691, Stockholm, Sweden.,Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, SE-11364, Stockholm, Sweden.,Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, US-03755, USA
| |
Collapse
|
13
|
Learning-induced biases in the ongoing dynamics of sensory representations predict stimulus generalization. Cell Rep 2022; 38:110340. [PMID: 35139386 DOI: 10.1016/j.celrep.2022.110340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/16/2021] [Accepted: 01/14/2022] [Indexed: 11/22/2022] Open
Abstract
Sensory stimuli have long been thought to be represented in the brain as activity patterns of specific neuronal assemblies. However, we still know relatively little about the long-term dynamics of sensory representations. Using chronic in vivo calcium imaging in the mouse auditory cortex, we find that sensory representations undergo continuous recombination, even under behaviorally stable conditions. Auditory cued fear conditioning introduces a bias into these ongoing dynamics, resulting in a long-lasting increase in the number of stimuli activating the same subset of neurons. This plasticity is specific for stimuli sharing representational similarity to the conditioned sound prior to conditioning and predicts behaviorally observed stimulus generalization. Our findings demonstrate that learning-induced plasticity leading to a representational linkage between the conditioned stimulus and non-conditioned stimuli weaves into ongoing dynamics of the brain rather than acting on an otherwise static substrate.
Collapse
|
14
|
Dissociated Role of Thalamic and Cortical Input to the Lateral Amygdala for Consolidation of Long-Term Fear Memory. J Neurosci 2021; 41:9561-9570. [PMID: 34667069 DOI: 10.1523/jneurosci.1167-21.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/25/2022] Open
Abstract
Post-encoding coordinated reactivation of memory traces distributed throughout interconnected brain regions is thought to be critical for consolidation of memories. However, little is known about the role of neural circuit pathways during post-learning periods for consolidation of memories. To investigate this question, we optogenetically silenced the inputs from both auditory cortex and thalamus in the lateral amygdala (LA) for 15 min immediately following auditory fear conditioning (FC) and examined its effect on fear memory formation in mice of both sexes. Optogenetic inhibition of both inputs disrupted long-term fear memory formation tested 24 h after FC. This effect was specific such that the same inhibition did not affect short-term memory and context-dependent memory. Moreover, long-term memory was intact if the inputs were inhibited at much later time points after FC (3 h or 1 d after FC), indicating that optical inhibition for 15 min itself does not produce any nonspecific deleterious effect on fear memory retrieval. Selective inhibition of thalamic input was sufficient to impair consolidation of auditory fear memory. In contrast, selective inhibition of cortical input disrupted remote fear memory without affecting recent memory. These results reveal a dissociated role of thalamic and cortical input to the LA during early post-learning periods for consolidation of long-term fear memory.SIGNIFICANCE STATEMENT Coordinated communications between brain regions are thought to be essential during post-learning periods for consolidation of memories. However, the role of specific neural circuit pathways in this process has been scarcely explored. Using a precise optogenetic inhibition of auditory input pathways, either thalamic or cortical or both, to the LA during post-training periods, we here show that thalamic input is required for consolidation of both recent and remote fear memory, whereas cortical input is crucial for consolidation of remote fear memory. These results reveal a dissociated role of auditory input pathways to the LA for consolidation of long-term fear memory.
Collapse
|
15
|
Ho S, Lajaunie R, Lerat M, Le M, Crépel V, Loulier K, Livet J, Kessler JP, Marcaggi P. A stable proportion of Purkinje cell inputs from parallel fibers are silent during cerebellar maturation. Proc Natl Acad Sci U S A 2021; 118:e2024890118. [PMID: 34740966 PMCID: PMC8609448 DOI: 10.1073/pnas.2024890118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2021] [Indexed: 11/18/2022] Open
Abstract
Cerebellar Purkinje neurons integrate information transmitted at excitatory synapses formed by granule cells. Although these synapses are considered essential sites for learning, most of them appear not to transmit any detectable electrical information and have been defined as silent. It has been proposed that silent synapses are required to maximize information storage capacity and ensure its reliability, and hence to optimize cerebellar operation. Such optimization is expected to occur once the cerebellar circuitry is in place, during its maturation and the natural and steady improvement of animal agility. We therefore investigated whether the proportion of silent synapses varies over this period, from the third to the sixth postnatal week in mice. Selective expression of a calcium indicator in granule cells enabled quantitative mapping of presynaptic activity, while postsynaptic responses were recorded by patch clamp in acute slices. Through this approach and the assessment of two anatomical features (the distance that separates adjacent planar Purkinje dendritic trees and the synapse density), we determined the average excitatory postsynaptic potential per synapse. Its value was four to eight times smaller than responses from paired recorded detectable connections, consistent with over 70% of synapses being silent. These figures remained remarkably stable across maturation stages. According to the proposed role for silent synapses, our results suggest that information storage capacity and reliability are optimized early during cerebellar maturation. Alternatively, silent synapses may have roles other than adjusting the information storage capacity and reliability.
Collapse
Affiliation(s)
- Shu Ho
- Aix-Marseille Université, INSERM, INMED, Marseille 13009, France
| | - Rebecca Lajaunie
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Marion Lerat
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris F-75012, France
| | - Mickaël Le
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris F-75012, France
| | - Valérie Crépel
- Aix-Marseille Université, INSERM, INMED, Marseille 13009, France
| | - Karine Loulier
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris F-75012, France
| | - Jean Livet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris F-75012, France
| | - Jean-Pierre Kessler
- Aix-Marseille Université, CNRS, Institut de Biologie du Développement de Marseille, UMR 7288, Marseille 13288, France
| | - Païkan Marcaggi
- Aix-Marseille Université, INSERM, INMED, Marseille 13009, France;
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
- Unité de Neurobiologie des Canaux Ioniques et de la Synapse, UMR 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| |
Collapse
|
16
|
Schug S, Benzing F, Steger A. Presynaptic stochasticity improves energy efficiency and helps alleviate the stability-plasticity dilemma. eLife 2021; 10:e69884. [PMID: 34661525 PMCID: PMC8716105 DOI: 10.7554/elife.69884] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/18/2021] [Indexed: 12/30/2022] Open
Abstract
When an action potential arrives at a synapse there is a large probability that no neurotransmitter is released. Surprisingly, simple computational models suggest that these synaptic failures enable information processing at lower metabolic costs. However, these models only consider information transmission at single synapses ignoring the remainder of the neural network as well as its overall computational goal. Here, we investigate how synaptic failures affect the energy efficiency of models of entire neural networks that solve a goal-driven task. We find that presynaptic stochasticity and plasticity improve energy efficiency and show that the network allocates most energy to a sparse subset of important synapses. We demonstrate that stabilising these synapses helps to alleviate the stability-plasticity dilemma, thus connecting a presynaptic notion of importance to a computational role in lifelong learning. Overall, our findings present a set of hypotheses for how presynaptic plasticity and stochasticity contribute to sparsity, energy efficiency and improved trade-offs in the stability-plasticity dilemma.
Collapse
Affiliation(s)
- Simon Schug
- Institute of Neuroinformatics, University of Zurich & ETH ZurichZurichSwitzerland
| | | | | |
Collapse
|
17
|
Dynamics of Dendritic Spines in Dorsal Striatum after Retrieval of Moderate and Strong Inhibitory Avoidance Learning. Neuroscience 2021; 497:134-145. [PMID: 34648867 DOI: 10.1016/j.neuroscience.2021.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/27/2021] [Accepted: 10/01/2021] [Indexed: 11/22/2022]
Abstract
In marked contrast to the ample literature showing that the dorsal striatum is engaged in memory consolidation, little is known about its involvement in memory retrieval. Recent findings demonstrated significant increments in dendritic spine density and mushroom spine counts in dorsal striatum after memory consolidation of moderate inhibitory avoidance (IA) training; further increments were found after strong training. Here, we provide evidence that in this region spine counts were also increased as a consequence of retrieval of moderate IA training, and even higher mushroom spine counts after retrieval of strong training; by contrast, there were fewer thin spines after retrieval. Similar changes in mushroom and thin spine populations were found in the ventral striatum (nucleus accumbens), but they were related to the aversive stimulation and not to memory retrieval. These results suggest that memory retrieval is a dynamic process which produces neuronal structural plasticity that might be necessary for maintaining or strengthening assemblies that encode stored information.
Collapse
|
18
|
Raman DV, O'Leary T. Optimal plasticity for memory maintenance during ongoing synaptic change. eLife 2021; 10:62912. [PMID: 34519270 PMCID: PMC8504970 DOI: 10.7554/elife.62912] [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: 09/08/2020] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
Synaptic connections in many brain circuits fluctuate, exhibiting substantial turnover and remodelling over hours to days. Surprisingly, experiments show that most of this flux in connectivity persists in the absence of learning or known plasticity signals. How can neural circuits retain learned information despite a large proportion of ongoing and potentially disruptive synaptic changes? We address this question from first principles by analysing how much compensatory plasticity would be required to optimally counteract ongoing fluctuations, regardless of whether fluctuations are random or systematic. Remarkably, we find that the answer is largely independent of plasticity mechanisms and circuit architectures: compensatory plasticity should be at most equal in magnitude to fluctuations, and often less, in direct agreement with previously unexplained experimental observations. Moreover, our analysis shows that a high proportion of learning-independent synaptic change is consistent with plasticity mechanisms that accurately compute error gradients.
Collapse
Affiliation(s)
- Dhruva V Raman
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Timothy O'Leary
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
19
|
Comas Mutis R, Espejo PJ, Martijena ID, Molina VA, Calfa GD. Temporal dynamic of the hippocampal structural plasticity associated with the fear memory destabilization/reconsolidation process. Hippocampus 2021; 31:1080-1091. [PMID: 34190369 DOI: 10.1002/hipo.23374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/17/2021] [Accepted: 06/06/2021] [Indexed: 11/11/2022]
Abstract
Reconsolidation of a contextual fear memory is a protein synthesis-dependent process in which a previously destabilized memory returns to a stable state. This process has become the subject of many studies due to its importance in memory processing, maintenance and updating, and its potential role as a therapeutical target in fear memory disorders such as phobias and post-traumatic stress disorder. In this sense, understanding the underlying mechanisms of memory reconsolidation is paramount in developing potential treatments for such memory dysfunctions. In the present work, we studied the interaction between two key neural structures involved in the reconsolidation process: the basolateral amygdala complex of the amygdala (BLA) and the dorsal hippocampus (DH). Our results show changes in the structural plasticity of the CA1 region of the DH in the form of dendritic spines density changes associated with the destabilization/reconsolidation process. Furthermore, we demonstrate a modulatory role of BLA over such structural plasticity by infusing different drugs such as ifenprodil, a destabilization blocker, and propranolol, a reconsolidation disruptor, in this brain structure. Altogether our work shows a particular temporal dynamic in the CA1 region of DH that accompanies the destabilization/reconsolidation process and aims to provide new information on the underlying mechanisms of this process that potentially contributes for a better understanding of memory storage, maintenance, expression and updating, and its potential medical applications.
Collapse
Affiliation(s)
- Ramiro Comas Mutis
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Pablo Javier Espejo
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Irene Delia Martijena
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Victor Alejandro Molina
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Gastón Diego Calfa
- IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| |
Collapse
|
20
|
Romero S, Hight AE, Clayton KK, Resnik J, Williamson RS, Hancock KE, Polley DB. Cellular and Widefield Imaging of Sound Frequency Organization in Primary and Higher Order Fields of the Mouse Auditory Cortex. Cereb Cortex 2021; 30:1603-1622. [PMID: 31667491 DOI: 10.1093/cercor/bhz190] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The mouse auditory cortex (ACtx) contains two core fields-primary auditory cortex (A1) and anterior auditory field (AAF)-arranged in a mirror reversal tonotopic gradient. The best frequency (BF) organization and naming scheme for additional higher order fields remain a matter of debate, as does the correspondence between smoothly varying global tonotopy and heterogeneity in local cellular tuning. Here, we performed chronic widefield and two-photon calcium imaging from the ACtx of awake Thy1-GCaMP6s reporter mice. Data-driven parcellation of widefield maps identified five fields, including a previously unidentified area at the ventral posterior extreme of the ACtx (VPAF) and a tonotopically organized suprarhinal auditory field (SRAF) that extended laterally as far as ectorhinal cortex. Widefield maps were stable over time, where single pixel BFs fluctuated by less than 0.5 octaves throughout a 1-month imaging period. After accounting for neuropil signal and frequency tuning strength, BF organization in neighboring layer 2/3 neurons was intermediate to the heterogeneous salt and pepper organization and the highly precise local organization that have each been described in prior studies. Multiscale imaging data suggest there is no ultrasonic field or secondary auditory cortex in the mouse. Instead, VPAF and a dorsal posterior (DP) field emerged as the strongest candidates for higher order auditory areas.
Collapse
Affiliation(s)
- Sandra Romero
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Ariel E Hight
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Kameron K Clayton
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Jennifer Resnik
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA
| | - Ross S Williamson
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA
| | - Kenneth E Hancock
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA
| | - Daniel B Polley
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA
| |
Collapse
|
21
|
Giorgi C, Marinelli S. Roles and Transcriptional Responses of Inhibitory Neurons in Learning and Memory. Front Mol Neurosci 2021; 14:689952. [PMID: 34211369 PMCID: PMC8239217 DOI: 10.3389/fnmol.2021.689952] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/18/2021] [Indexed: 12/26/2022] Open
Abstract
Increasing evidence supports a model whereby memories are encoded by sparse ensembles of neurons called engrams, activated during memory encoding and reactivated upon recall. An engram consists of a network of cells that undergo long-lasting modifications of their transcriptional programs and connectivity. Ground-breaking advancements in this field have been made possible by the creative exploitation of the characteristic transcriptional responses of neurons to activity, allowing both engram labeling and manipulation. Nevertheless, numerous aspects of engram cell-type composition and function remain to be addressed. As recent transcriptomic studies have revealed, memory encoding induces persistent transcriptional and functional changes in a plethora of neuronal subtypes and non-neuronal cells, including glutamatergic excitatory neurons, GABAergic inhibitory neurons, and glia cells. Dissecting the contribution of these different cellular classes to memory engram formation and activity is quite a challenging yet essential endeavor. In this review, we focus on the role played by the GABAergic inhibitory component of the engram through two complementary lenses. On one hand, we report on available physiological evidence addressing the involvement of inhibitory neurons to different stages of memory formation, consolidation, storage and recall. On the other, we capitalize on a growing number of transcriptomic studies that profile the transcriptional response of inhibitory neurons to activity, revealing important clues on their potential involvement in learning and memory processes. The picture that emerges suggests that inhibitory neurons are an essential component of the engram, likely involved in engram allocation, in tuning engram excitation and in storing the memory trace.
Collapse
Affiliation(s)
- Corinna Giorgi
- CNR, Institute of Molecular Biology and Pathology, Rome, Italy.,European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| | - Silvia Marinelli
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| |
Collapse
|
22
|
Ma S, Zuo Y. Synaptic modifications in learning and memory - A dendritic spine story. Semin Cell Dev Biol 2021; 125:84-90. [PMID: 34020876 DOI: 10.1016/j.semcdb.2021.05.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/06/2021] [Accepted: 05/12/2021] [Indexed: 11/15/2022]
Abstract
Synapses are specialized sites where neurons connect and communicate with each other. Activity-dependent modification of synaptic structure and function provides a mechanism for learning and memory. The advent of high-resolution time-lapse imaging in conjunction with fluorescent biosensors and actuators enables researchers to monitor and manipulate the structure and function of synapses both in vitro and in vivo. This review focuses on recent imaging studies on the synaptic modification underlying learning and memory.
Collapse
Affiliation(s)
- Shaorong Ma
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
| |
Collapse
|
23
|
Zelenka O, Novak O, Brunova A, Syka J. Heterogeneous associative plasticity in the auditory cortex induced by fear learning - novel insight into the classical conditioning paradigm. Physiol Res 2021; 70:447-460. [PMID: 33982575 DOI: 10.33549/physiolres.934559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We used two-photon calcium imaging with single-cell and cell-type resolution. Fear conditioning induced heterogeneous tuning shifts at single-cell level in the auditory cortex, with shifts both to CS+ frequency and to the control CS- stimulus frequency. We thus extend the view of simple expansion of CS+ tuned regions. Instead of conventional freezing reactions only, we observe selective orienting responses towards the conditioned stimuli. The orienting responses were often followed by escape behavior.
Collapse
Affiliation(s)
- O Zelenka
- Department of Physiology, Second Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
| | | | | | | |
Collapse
|
24
|
Peter M, Aschauer DF, Rose R, Sinning A, Grössl F, Kargl D, Kraitsy K, Burkard TR, Luhmann HJ, Haubensak W, Rumpel S. Rapid nucleus-scale reorganization of chromatin in neurons enables transcriptional adaptation for memory consolidation. PLoS One 2021; 16:e0244038. [PMID: 33951054 PMCID: PMC8099114 DOI: 10.1371/journal.pone.0244038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/05/2021] [Indexed: 12/27/2022] Open
Abstract
The interphase nucleus is functionally organized in active and repressed territories defining the transcriptional status of the cell. However, it remains poorly understood how the nuclear architecture of neurons adapts in response to behaviorally relevant stimuli that trigger fast alterations in gene expression patterns. Imaging of fluorescently tagged nucleosomes revealed that pharmacological manipulation of neuronal activity in vitro and auditory cued fear conditioning in vivo induce nucleus-scale restructuring of chromatin within minutes. Furthermore, the acquisition of auditory fear memory is impaired after infusion of a drug into auditory cortex which blocks chromatin reorganization in vitro. We propose that active chromatin movements at the nucleus scale act together with local gene-specific modifications to enable transcriptional adaptations at fast time scales. Introducing a transgenic mouse line for photolabeling of histones, we extend the realm of systems available for imaging of chromatin dynamics to living animals.
Collapse
Affiliation(s)
- Manuel Peter
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Dominik F. Aschauer
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes-Gutenberg University, Mainz, Germany
| | - Renata Rose
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes-Gutenberg University, Mainz, Germany
| | - Anne Sinning
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes-Gutenberg University, Mainz, Germany
| | - Florian Grössl
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Dominic Kargl
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Klaus Kraitsy
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
- Preclinical Phenotyping, Vienna Biocenter Core Facilities, Vienna, Austria
| | - Thomas R. Burkard
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter, Vienna, Austria
| | - Heiko J. Luhmann
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes-Gutenberg University, Mainz, Germany
| | - Wulf Haubensak
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Simon Rumpel
- Institute of Physiology, Focus Program Translational Neurosciences, University Medical Center, Johannes-Gutenberg University, Mainz, Germany
| |
Collapse
|
25
|
Robustness to Noise in the Auditory System: A Distributed and Predictable Property. eNeuro 2021; 8:ENEURO.0043-21.2021. [PMID: 33632813 PMCID: PMC7986545 DOI: 10.1523/eneuro.0043-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/30/2022] Open
Abstract
Background noise strongly penalizes auditory perception of speech in humans or vocalizations in animals. Despite this, auditory neurons are still able to detect communications sounds against considerable levels of background noise. We collected neuronal recordings in cochlear nucleus (CN), inferior colliculus (IC), auditory thalamus, and primary and secondary auditory cortex in response to vocalizations presented either against a stationary or a chorus noise in anesthetized guinea pigs at three signal-to-noise ratios (SNRs; −10, 0, and 10 dB). We provide evidence that, at each level of the auditory system, five behaviors in noise exist within a continuum, from neurons with high-fidelity representations of the signal, mostly found in IC and thalamus, to neurons with high-fidelity representations of the noise, mostly found in CN for the stationary noise and in similar proportions in each structure for the chorus noise. The two cortical areas displayed fewer robust responses than the IC and thalamus. Furthermore, between 21% and 72% of the neurons (depending on the structure) switch categories from one background noise to another, even if the initial assignment of these neurons to a category was confirmed by a severe bootstrap procedure. Importantly, supervised learning pointed out that assigning a recording to one of the five categories can be predicted up to a maximum of 70% based on both the response to signal alone and noise alone.
Collapse
|
26
|
Corticostriatal Plasticity Established by Initial Learning Persists after Behavioral Reversal. eNeuro 2021; 8:ENEURO.0209-20.2021. [PMID: 33547044 PMCID: PMC7986528 DOI: 10.1523/eneuro.0209-20.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/08/2020] [Accepted: 01/09/2021] [Indexed: 12/03/2022] Open
Abstract
The neural mechanisms that allow animals to adapt their previously learned associations in response to changes in the environment remain poorly understood. To probe the synaptic mechanisms that mediate such adaptive behavior, we trained mice on an auditory-motor reversal task, and tracked changes in the strength of corticostriatal synapses associated with the formation of learned associations. Using a ChR2-based electrophysiological assay in acute striatal slices, we measured the strength of these synapses after animals learned to pair auditory stimuli with specific actions. Here, we report that the pattern of synaptic strength initially established by learning remains unchanged even when the task contingencies are reversed. Our findings reveal that synaptic changes associated with the initial acquisition of this task are not erased or overwritten, and that behavioral reversal of learned associations may recruit a separate neural circuit. These results suggest a more complex role of the striatum in regulating flexible behaviors where activity of striatal neurons may vary given the behavioral contexts of specific stimulus-action associations.
Collapse
|
27
|
Xing B, Mack NR, Guo KM, Zhang YX, Ramirez B, Yang SS, Lin L, Wang DV, Li YC, Gao WJ. A Subpopulation of Prefrontal Cortical Neurons Is Required for Social Memory. Biol Psychiatry 2021; 89:521-531. [PMID: 33190846 PMCID: PMC7867585 DOI: 10.1016/j.biopsych.2020.08.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 08/12/2020] [Accepted: 08/24/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND The medial prefrontal cortex (mPFC) is essential for social behaviors, yet whether and how it encodes social memory remains unclear. METHODS We combined whole-cell patch recording, morphological analysis, optogenetic/chemogenetic manipulation, and the TRAP (targeted recombination in active populations) transgenic mouse tool to study the social-associated neural populations in the mPFC. RESULTS Fos-TRAPed prefrontal social-associated neurons are excitatory pyramidal neurons with relatively small soma sizes and thin-tufted apical dendrite. These cells exhibit intrinsic firing features of dopamine D1 receptor-like neurons, show persisting firing pattern after social investigation, and project dense axons to nucleus accumbens. In behaving TRAP mice, selective inhibition of prefrontal social-associated neurons does not affect social investigation but does impair subsequent social recognition, whereas optogenetic reactivation of their projections to the nucleus accumbens enables recall of a previously encountered but "forgotten" mouse. Moreover, chemogenetic activation of mPFC-to-nucleus accumbens projections ameliorates MK-801-induced social memory impairments. CONCLUSIONS Our results characterize the electrophysiological and morphological features of social-associated neurons in the mPFC and indicate that these Fos-labeled, social-activated prefrontal neurons are necessary and sufficient for social memory.
Collapse
Affiliation(s)
- Bo Xing
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Nancy R. Mack
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Kai-Ming Guo
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China,Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yu-Xiang Zhang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Billy Ramirez
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Sha-Sha Yang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Li Lin
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China.
| | - Dong V. Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Yan-Chun Li
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Wen-Jun Gao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania.
| |
Collapse
|
28
|
Simonetti M, Paldy E, Njoo C, Bali KK, Worzfeld T, Pitzer C, Kuner T, Offermanns S, Mauceri D, Kuner R. The impact of Semaphorin 4C/Plexin-B2 signaling on fear memory via remodeling of neuronal and synaptic morphology. Mol Psychiatry 2021; 26:1376-1398. [PMID: 31444474 PMCID: PMC7985029 DOI: 10.1038/s41380-019-0491-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 12/19/2022]
Abstract
Aberrant fear is a cornerstone of several psychiatric disorders. Consequently, there is large interest in elucidation of signaling mechanisms that link extracellular cues to changes in neuronal function and structure in brain pathways that are important in the generation and maintenance of fear memory and its behavioral expression. Members of the Plexin-B family of receptors for class 4 semaphorins play important roles in developmental plasticity of neurons, and their expression persists in some areas of the adult nervous system. Here, we aimed to elucidate the role of Semaphorin 4C (Sema4C) and its cognate receptor, Plexin-B2, in the expression of contextual and cued fear memory, setting a mechanistic focus on structural plasticity and exploration of contributing signaling pathways. We observed that Plexin-B2 and Sema4C are expressed in forebrain areas related to fear memory, such as the anterior cingulate cortex, amygdala and the hippocampus, and their expression is regulated by aversive stimuli that induce fear memory. By generating forebrain-specific Plexin-B2 knockout mice and analyzing fear-related behaviors, we demonstrate that Sema4C-PlexinB2 signaling plays a crucial functional role in the recent and remote recall of fear memory. Detailed neuronal morphological analyses revealed that Sema4C-PlexinB2 signaling largely mediates fear-induced structural plasticity by enhancing dendritic ramifications and modulating synaptic density in the adult hippocampus. Analyses on signaling-related mutant mice showed that these functions are mediated by PlexinB2-dependent RhoA activation. These results deliver important insights into the mechanistic understanding of maladaptive plasticity in fear circuits and have implications for novel therapeutic strategies against fear-related disorders.
Collapse
Affiliation(s)
- Manuela Simonetti
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Eszter Paldy
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christian Njoo
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Kiran Kumar Bali
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Thomas Worzfeld
- grid.10253.350000 0004 1936 9756Institute of Pharmacology, Marburg University, Karl-von-Frisch-Str. 1, 35043 Marburg, Germany ,grid.418032.c0000 0004 0491 220XDepartment of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany
| | - Claudia Pitzer
- grid.7700.00000 0001 2190 4373Interdisciplinary Neurobehavioral Core, Heidelberg University, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany
| | - Thomas Kuner
- grid.7700.00000 0001 2190 4373Anatomy and Cell Biology Institute, Heidelberg University, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany
| | - Stefan Offermanns
- grid.418032.c0000 0004 0491 220XDepartment of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany
| | - Daniela Mauceri
- grid.7700.00000 0001 2190 4373Department of Neurobiology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany.
| |
Collapse
|
29
|
Rule ME, Loback AR, Raman DV, Driscoll LN, Harvey CD, O'Leary T. Stable task information from an unstable neural population. eLife 2020; 9:51121. [PMID: 32660692 PMCID: PMC7392606 DOI: 10.7554/elife.51121] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 06/17/2020] [Indexed: 02/06/2023] Open
Abstract
Over days and weeks, neural activity representing an animal's position and movement in sensorimotor cortex has been found to continually reconfigure or 'drift' during repeated trials of learned tasks, with no obvious change in behavior. This challenges classical theories, which assume stable engrams underlie stable behavior. However, it is not known whether this drift occurs systematically, allowing downstream circuits to extract consistent information. Analyzing long-term calcium imaging recordings from posterior parietal cortex in mice (Mus musculus), we show that drift is systematically constrained far above chance, facilitating a linear weighted readout of behavioral variables. However, a significant component of drift continually degrades a fixed readout, implying that drift is not confined to a null coding space. We calculate the amount of plasticity required to compensate drift independently of any learning rule, and find that this is within physiologically achievable bounds. We demonstrate that a simple, biologically plausible local learning rule can achieve these bounds, accurately decoding behavior over many days.
Collapse
Affiliation(s)
- Michael E Rule
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Adrianna R Loback
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Dhruva V Raman
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Laura N Driscoll
- Department of Electrical Engineering, Stanford University, Stanford, United States
| | | | - Timothy O'Leary
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
30
|
Pereira AG, Farias M, Moita MA. Thalamic, cortical, and amygdala involvement in the processing of a natural sound cue of danger. PLoS Biol 2020; 18:e3000674. [PMID: 32396574 PMCID: PMC7217448 DOI: 10.1371/journal.pbio.3000674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 04/09/2020] [Indexed: 12/21/2022] Open
Abstract
Animals use auditory cues generated by defensive responses of others to detect impending danger. Here we identify a neural circuit in rats involved in the detection of one such auditory cue, the cessation of movement-evoked sound resulting from freezing. This circuit comprises the dorsal subnucleus of the medial geniculate body (MGD) and downstream areas, the ventral area of the auditory cortex (VA), and the lateral amygdala (LA). This study suggests a role for the auditory offset pathway in processing a natural sound cue of threat.
Collapse
Affiliation(s)
- Ana G. Pereira
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
| | - Matheus Farias
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
| | - Marta A. Moita
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
- * E-mail:
| |
Collapse
|
31
|
MacDonald ML, Garver M, Newman J, Sun Z, Kannarkat J, Salisbury R, Glausier J, Ding Y, Lewis DA, Yates N, Sweet RA. Synaptic Proteome Alterations in the Primary Auditory Cortex of Individuals With Schizophrenia. JAMA Psychiatry 2020; 77:86-95. [PMID: 31642882 PMCID: PMC6813579 DOI: 10.1001/jamapsychiatry.2019.2974] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/10/2019] [Indexed: 12/28/2022]
Abstract
Importance Findings from unbiased genetic studies have consistently implicated synaptic protein networks in schizophrenia, but the molecular pathologic features within these networks and their contribution to the synaptic and circuit deficits thought to underlie disease symptoms remain unknown. Objective To determine whether protein levels are altered within synapses from the primary auditory cortex (A1) of individuals with schizophrenia and, if so, whether these differences are restricted to the synapse or occur throughout the gray matter. Design, Setting, and Participants This paired case-control study included tissue samples from individuals with schizophrenia obtained from the Allegheny County Office of the Medical Examiner. An independent panel of health care professionals made consensus DSM-IV diagnoses. Each tissue sample from an individual with schizophrenia was matched by sex, age, and postmortem interval with 1 sample from an unaffected control individual. Targeted mass spectrometry was used to measure protein levels in A1 gray matter homogenate and synaptosome preparations. All experimenters were blinded to diagnosis. Mass spectrometry data were collected from September 26 through November 4, 2016, and analyzed from November 3, 2016, to July 15, 2019. Main Outcomes and Measures Primary measures were homogenate and synaptosome protein levels and their coregulation network features. Hypotheses generated before data collection were (1) that levels of canonical postsynaptic proteins in A1 synaptosome preparations would differ between individuals with schizophrenia and controls and (2) that these differences would not be explained by changes in total A1 homogenate protein levels. Results Synaptosome and homogenate protein levels were investigated in 48 individuals with a schizophrenia diagnosis and 48 controls (mean age in both groups, 48 years [range, 17-83 years]); each group included 35 males (73%) and 13 females (27%). Robust alterations (statistical cutoff set at an adjusted Limma P < .05) were observed in synaptosome levels of canonical mitochondrial and postsynaptic proteins that were highly coregulated and not readily explained by postmortem interval, antipsychotic drug treatment, synaptosome yield, or underlying alterations in homogenate protein levels. Conclusions and Relevance These findings suggest a robust and highly coordinated rearrangement of the synaptic proteome. In line with unbiased genetic findings, alterations in synaptic levels of postsynaptic proteins were identified, providing a road map to identify the specific cells and circuits that are impaired in individuals with schizophrenia A1.
Collapse
Affiliation(s)
- Matthew L. MacDonald
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
- Biomedical Mass Spectrometry Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Megan Garver
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jason Newman
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Zhe Sun
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Joseph Kannarkat
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ryan Salisbury
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jill Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ying Ding
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David A. Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nathan Yates
- Biomedical Mass Spectrometry Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert A. Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|
32
|
Dalmay T, Abs E, Poorthuis RB, Hartung J, Pu DL, Onasch S, Lozano YR, Signoret-Genest J, Tovote P, Gjorgjieva J, Letzkus JJ. A Critical Role for Neocortical Processing of Threat Memory. Neuron 2019; 104:1180-1194.e7. [PMID: 31727549 DOI: 10.1016/j.neuron.2019.09.025] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 08/10/2019] [Accepted: 09/17/2019] [Indexed: 01/10/2023]
Abstract
Memory of cues associated with threat is critical for survival and a leading model for elucidating how sensory information is linked to adaptive behavior by learning. Although the brain-wide circuits mediating auditory threat memory have been intensely investigated, it remains unclear whether the auditory cortex is critically involved. Here we use optogenetic activity manipulations in defined cortical areas and output pathways, viral tracing, pathway-specific in vivo 2-photon calcium imaging, and computational analyses of population plasticity to reveal that the auditory cortex is selectively required for conditioning to complex stimuli, whereas the adjacent temporal association cortex controls all forms of auditory threat memory. More temporal areas have a stronger effect on memory and more neurons projecting to the lateral amygdala, which control memory to complex stimuli through a balanced form of population plasticity that selectively supports discrimination of significant sensory stimuli. Thus, neocortical processing plays a critical role in cued threat memory.
Collapse
Affiliation(s)
- Tamas Dalmay
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany
| | - Elisabeth Abs
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany
| | | | - Jan Hartung
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany
| | - De-Lin Pu
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany
| | - Sebastian Onasch
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany
| | - Yave R Lozano
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Jérémy Signoret-Genest
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany; Department of Psychiatry, Center of Mental Health, 97078 Würzburg, Germany
| | - Philip Tovote
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Julijana Gjorgjieva
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany; School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | | |
Collapse
|
33
|
Nierhaus T, Vidaurre C, Sannelli C, Mueller K, Villringer A. Immediate brain plasticity after one hour of brain–computer interface (BCI). J Physiol 2019; 599:2435-2451. [DOI: 10.1113/jp278118] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022] Open
Affiliation(s)
- Till Nierhaus
- Department of Neurology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- Neurocomputation and Neuroimaging Unit (NNU), Department of Education and Psychology Freie Universität Berlin Berlin Germany
| | - Carmen Vidaurre
- Machine Learning Group EE & Computer Science Faculty TU‐Berlin Germany
- Department Statistics, Informatics and Mathematics Public University of Navarra Spain
| | - Claudia Sannelli
- Machine Learning Group EE & Computer Science Faculty TU‐Berlin Germany
| | - Klaus‐Robert Mueller
- Machine Learning Group EE & Computer Science Faculty TU‐Berlin Germany
- Department of Brain and Cognitive Engineering Korea University Anam‐dong Seongbuk‐gu Seoul 02841 Korea
- Max Planck Institute for Informatics Saarbrücken Germany
| | - Arno Villringer
- Department of Neurology Max Planck Institute for Human Cognitive and Brain Sciences Leipzig Germany
- MindBrainBody Institute at Berlin School of Mind and Brain Charité Universitätsmedizin Berlin and Humboldt‐University Berlin Germany
| |
Collapse
|
34
|
Sun X, Han R, Cheng T, Zheng Y, Xiao J, So KF, Zhang L. Corticosterone-mediated microglia activation affects dendritic spine plasticity and motor learning functions in minimal hepatic encephalopathy. Brain Behav Immun 2019; 82:178-187. [PMID: 31437533 DOI: 10.1016/j.bbi.2019.08.184] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 01/20/2023] Open
Abstract
Minimal hepatic encephalopathy (MHE) is characterized as cognitive deficits including memory and learning dysfunctions after liver injuries or hepatic diseases. Our understandings of neurological mechanisms of MHE-associated cognitive syndromes, however, are far from complete. In the current study we generated a mouse MHE model by repetitive administrations of thioacetamide (TAA), which induced hyperammonemia plus elevated proinflammatory cytokines in both the general circulation and motor cortex. MHE mice presented prominent motor learning deficits, which were associated with excess dendritic spine pruning in the motor cortex under 2-photon in vivo microscopy. The pharmaceutical blockade of glucocorticoid receptor or suppression of its biosynthesis further rescued motor learning deficits and synaptic protein loss. Moreover, MHE mice presented microglial activation, which can be alleviated after glucocorticoid pathway inhibition. In sum, our data demonstrates corticosterone-induced microglial activation, synaptic over-pruning and motor learning impairments in MHE, providing new insights for MHE pathogenesis and potential targets of clinical interventions.
Collapse
Affiliation(s)
- Xiaoming Sun
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China
| | - Rui Han
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China
| | - Tong Cheng
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China
| | - Yuhan Zheng
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China
| | - Jia Xiao
- Laboratory of Neuroendocrinology, College of Life Sciences, Fujian Normal University, Fuzhou, PR China; Institute of Clinical Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, PR China; School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kwok-Fai So
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China; State Key Laboratory of Brain and Cognitive Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, PR China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macau Greater Bay Area, Guangzhou, PR China.
| | - Li Zhang
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, PR China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, PR China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macau Greater Bay Area, Guangzhou, PR China.
| |
Collapse
|
35
|
de la Fuente V, Medina C, Falasco G, Urrutia L, Kravitz AV, Urbano FJ, Vázquez S, Pedreira ME, Romano A. The lateral neocortex is critical for contextual fear memory reconsolidation. Sci Rep 2019; 9:12157. [PMID: 31434945 PMCID: PMC6704072 DOI: 10.1038/s41598-019-48340-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 08/02/2019] [Indexed: 11/30/2022] Open
Abstract
Memories are a product of the concerted activity of many brain areas. Deregulation of consolidation and reprocessing of mnemonic traces that encode fearful experiences might result in fear-related psychopathologies. Here, we assessed how pre-established memories change with experience, particularly the labilization/reconsolidation of memory, using the whole-brain analysis technique of positron emission tomography in male mice. We found differences in glucose consumption in the lateral neocortex, hippocampus and amygdala in mice that underwent labilization/reconsolidation processes compared to animals that did not reactivate a fear memory. We used chemogenetics to obtain insight into the role of cortical areas in these phases of memory and found that the lateral neocortex is necessary for fear memory reconsolidation. Inhibition of lateral neocortex during reconsolidation altered glucose consumption levels in the amygdala. Using an optogenetic/neuronal recording-based strategy we observed that the lateral neocortex is functionally connected with the amygdala, which, along with retrograde labeling using fluorophore-conjugated cholera toxin subunit B, support a monosynaptic connection between these areas and poses this connection as a hot-spot in the circuits involved in reactivation of fear memories.
Collapse
Affiliation(s)
- Verónica de la Fuente
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina. .,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina.
| | - Candela Medina
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Germán Falasco
- Centro de Imágenes Moleculares, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia (FLENI), Escobar, Buenos Aires, Argentina
| | - Leandro Urrutia
- Centro de Imágenes Moleculares, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia (FLENI), Escobar, Buenos Aires, Argentina
| | - Alexxai V Kravitz
- National Institute of Diabetes and Kidney and Digestive Diseases, Bethesda, MD, 20814, USA
| | - Francisco J Urbano
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Silvia Vázquez
- Centro de Imágenes Moleculares, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia (FLENI), Escobar, Buenos Aires, Argentina
| | - María Eugenia Pedreira
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Arturo Romano
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| |
Collapse
|
36
|
Aizenberg M, Rolón-Martínez S, Pham T, Rao W, Haas JS, Geffen MN. Projection from the Amygdala to the Thalamic Reticular Nucleus Amplifies Cortical Sound Responses. Cell Rep 2019; 28:605-615.e4. [PMID: 31315041 PMCID: PMC7081884 DOI: 10.1016/j.celrep.2019.06.050] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 04/29/2019] [Accepted: 06/13/2019] [Indexed: 12/16/2022] Open
Abstract
Many forms of behavior require selective amplification of neuronal representations of relevant environmental signals. Emotional learning enhances sensory responses in the sensory cortex, yet the underlying circuits remain poorly understood. We identify a pathway between the basolateral amygdala (BLA), an emotional learning center in the mouse brain, and the inhibitory reticular nucleus of the thalamus (TRN). Optogenetic activation of BLA suppressed spontaneous, but not tone-evoked, activity in the auditory cortex (AC), amplifying tone-evoked responses. Viral tracing identified BLA projections terminating at TRN. Optogenetic activation of amygdala-TRN projections further amplified tone-evoked responses in the auditory thalamus and cortex. The results are explained by a computational model of the thalamocortical circuitry, in which activation of TRN by BLA primes thalamocortical neurons to relay relevant sensory input. This circuit mechanism shines a neural spotlight on behaviorally relevant signals and provides a potential target for the treatment of neuropsychological disorders.
Collapse
Affiliation(s)
- Mark Aizenberg
- Department of Otorhinolaryngology: HNS, Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
| | - Solymar Rolón-Martínez
- Department of Otorhinolaryngology: HNS, Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
| | - Tuan Pham
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Winnie Rao
- Department of Otorhinolaryngology: HNS, Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
| | - Julie S Haas
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Maria N Geffen
- Department of Otorhinolaryngology: HNS, Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
37
|
Bajo VM, Nodal FR, Korn C, Constantinescu AO, Mann EO, Boyden ES, King AJ. Silencing cortical activity during sound-localization training impairs auditory perceptual learning. Nat Commun 2019; 10:3075. [PMID: 31300665 PMCID: PMC6625986 DOI: 10.1038/s41467-019-10770-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 05/28/2019] [Indexed: 11/09/2022] Open
Abstract
The brain has a remarkable capacity to adapt to changes in sensory inputs and to learn from experience. However, the neural circuits responsible for this flexible processing remain poorly understood. Using optogenetic silencing of ArchT-expressing neurons in adult ferrets, we show that within-trial activity in primary auditory cortex (A1) is required for training-dependent recovery in sound-localization accuracy following monaural deprivation. Because localization accuracy under normal-hearing conditions was unaffected, this highlights a specific role for cortical activity in learning. A1-dependent plasticity appears to leave a memory trace that can be retrieved, facilitating adaptation during a second period of monaural deprivation. However, in ferrets in which learning was initially disrupted by perturbing A1 activity, subsequent optogenetic suppression during training no longer affected localization accuracy when one ear was occluded. After the initial learning phase, the reweighting of spatial cues that primarily underpins this plasticity may therefore occur in A1 target neurons.
Collapse
Affiliation(s)
- Victoria M Bajo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
| | - Fernando R Nodal
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Clio Korn
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.,UCSF School of Medicine, San Francisco, CA, 94143-0410, USA
| | - Alexandra O Constantinescu
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.,Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, UK
| | - Edward O Mann
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Edward S Boyden
- Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Andrew J King
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
| |
Collapse
|
38
|
Schicknick H, Henschke JU, Budinger E, Ohl FW, Gundelfinger ED, Tischmeyer W. β-adrenergic modulation of discrimination learning and memory in the auditory cortex. Eur J Neurosci 2019; 50:3141-3163. [PMID: 31162753 PMCID: PMC6900137 DOI: 10.1111/ejn.14480] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 05/27/2019] [Accepted: 05/31/2019] [Indexed: 01/11/2023]
Abstract
Despite vast literature on catecholaminergic neuromodulation of auditory cortex functioning in general, knowledge about its role for long‐term memory formation is scarce. Our previous pharmacological studies on cortex‐dependent frequency‐modulated tone‐sweep discrimination learning of Mongolian gerbils showed that auditory‐cortical D1/5‐dopamine receptor activity facilitates memory consolidation and anterograde memory formation. Considering overlapping functions of D1/5‐dopamine receptors and β‐adrenoceptors, we hypothesised a role of β‐adrenergic signalling in the auditory cortex for sweep discrimination learning and memory. Supporting this hypothesis, the β1/2‐adrenoceptor antagonist propranolol bilaterally applied to the gerbil auditory cortex after task acquisition prevented the discrimination increment that was normally monitored 1 day later. The increment in the total number of hurdle crossings performed in response to the sweeps per se was normal. Propranolol infusion after the seventh training session suppressed the previously established sweep discrimination. The suppressive effect required antagonist injection in a narrow post‐session time window. When applied to the auditory cortex 1 day before initial conditioning, β1‐adrenoceptor‐antagonising and β1‐adrenoceptor‐stimulating agents retarded and facilitated, respectively, sweep discrimination learning, whereas β2‐selective drugs were ineffective. In contrast, single‐sweep detection learning was normal after propranolol infusion. By immunohistochemistry, β1‐ and β2‐adrenoceptors were identified on the neuropil and somata of pyramidal and non‐pyramidal neurons of the gerbil auditory cortex. The present findings suggest that β‐adrenergic signalling in the auditory cortex has task‐related importance for discrimination learning of complex sounds: as previously shown for D1/5‐dopamine receptor signalling, β‐adrenoceptor activity supports long‐term memory consolidation and reconsolidation; additionally, tonic input through β1‐adrenoceptors may control mechanisms permissive for memory acquisition.
Collapse
Affiliation(s)
- Horst Schicknick
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Julia U Henschke
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Institute of Cognitive Neurology and Dementia Research, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Eike Budinger
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Frank W Ohl
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Institute of Biology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Center for Behavioral Brain Sciences, Magdeburg, Germany.,Department Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Molecular Neurobiology, Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Wolfgang Tischmeyer
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| |
Collapse
|
39
|
Wang Y, Li Z, Tian Z, Wang X, Li Y, Qin L. Emotional arousal modifies auditory steady state response in the auditory cortex and prefrontal cortex of rats. Stress 2019; 22:492-500. [PMID: 30896270 DOI: 10.1080/10253890.2019.1583203] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Emotional state has been shown to influence cognitive performance. However, the influence of mood on auditory processing is not fully understood. The auditory steady state response (ASSR) is the entrainment of neural activities elicited by periodic auditory stimulation, which is commonly used to evaluate the sensory and cognitive functions of brain. It has been shown that ASSR at 40 Hz is impaired at some psychotic disorders, such as schizophrenia and bipolar disorder. The primary goal of this study is to investigate the effect of emotional arousal on ASSR. To this end, we performed simultaneous recordings of local field potential (LFP) in response to 40 Hz click-train stimuli in the primary auditory cortex (A1) and medial prefront cortex (mPFC) of rats. During the electrophysiological recording, a negative mood was induced by means of the foot shocks occurred randomly in the inter-stimulus intervals. We found that both the power and phase-locking of ASSR in A1 were significantly increased under arousal condition, and phase-locking of ASSR in mPFC was also increased. The enhanced ASSRs were accompanied by an increase in coherence between A1 and mPFC. Our results suggest that A1-to-mPFC information transfer is enhanced under arousal state and the functional connectivity between mPFC and A1 may contribute to the emotional modulation of auditory process.
Collapse
Affiliation(s)
- Yuchen Wang
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| | - Zijie Li
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| | - Zemin Tian
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| | - Xuejiao Wang
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| | - Yingzhuo Li
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| | - Ling Qin
- a Department of Physiology, School of Life Science , China Medical University , Shenyang , Liaoning Province , P. R. China
| |
Collapse
|
40
|
Fauth MJ, van Rossum MC. Self-organized reactivation maintains and reinforces memories despite synaptic turnover. eLife 2019; 8:43717. [PMID: 31074745 PMCID: PMC6546393 DOI: 10.7554/elife.43717] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/30/2019] [Indexed: 01/21/2023] Open
Abstract
Long-term memories are believed to be stored in the synapses of cortical neuronal networks. However, recent experiments report continuous creation and removal of cortical synapses, which raises the question how memories can survive on such a variable substrate. Here, we study the formation and retention of associative memory in a computational model based on Hebbian cell assemblies in the presence of both synaptic and structural plasticity. During rest periods, such as may occur during sleep, the assemblies reactivate spontaneously, reinforcing memories against ongoing synapse removal and replacement. Brief daily reactivations during rest-periods suffice to not only maintain the assemblies, but even strengthen them, and improve pattern completion, consistent with offline memory gains observed experimentally. While the connectivity inside memory representations is strengthened during rest phases, connections in the rest of the network decay and vanish thus reconciling apparently conflicting hypotheses of the influence of sleep on cortical connectivity.
Collapse
Affiliation(s)
- Michael Jan Fauth
- School of Informatics, University of Edinburgh, Edinburgh, United Kingdom.,Third Physics Institute, University of Göttingen, Göttingen, Germany
| | - Mark Cw van Rossum
- School of Psychology, University of Nottingham, Nottingham, United Kingdom.,School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| |
Collapse
|
41
|
Yang Y, Lu J, Zuo Y. Changes of Synaptic Structures Associated with Learning, Memory and Diseases. BRAIN SCIENCE ADVANCES 2019. [DOI: 10.26599/bsa.2018.2018.9050012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptic plasticity is widely believed to be the cellular basis of learning and memory. It is influenced by various factors including development, sensory experiences, and brain disorders. Long-term synaptic plasticity is accompanied by protein synthesis and trafficking, leading to structural changes of the synapse. In this review, we focus on the synaptic structural plasticity, which has mainly been studied with in vivo two-photon laser scanning microscopy. We also discuss how a special type of synapses, the multi-contact synapses (including those formed by multi-synaptic boutons and multi-synaptic spines), are associated with experience and learning.
Collapse
Affiliation(s)
- Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ju Lu
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
| | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
| |
Collapse
|
42
|
Cortical recruitment determines learning dynamics and strategy. Nat Commun 2019; 10:1479. [PMID: 30931939 PMCID: PMC6443669 DOI: 10.1038/s41467-019-09450-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 03/12/2019] [Indexed: 12/26/2022] Open
Abstract
Salience is a broad and widely used concept in neuroscience whose neuronal correlates, however, remain elusive. In behavioral conditioning, salience is used to explain various effects, such as stimulus overshadowing, and refers to how fast and strongly a stimulus can be associated with a conditioned event. Here, we identify sounds of equal intensity and perceptual detectability, which due to their spectro-temporal content recruit different levels of population activity in mouse auditory cortex. When using these sounds as cues in a Go/NoGo discrimination task, the degree of cortical recruitment matches the salience parameter of a reinforcement learning model used to analyze learning speed. We test an essential prediction of this model by training mice to discriminate light-sculpted optogenetic activity patterns in auditory cortex, and verify that cortical recruitment causally determines association or overshadowing of the stimulus components. This demonstrates that cortical recruitment underlies major aspects of stimulus salience during reinforcement learning.
Collapse
|
43
|
Fear conditioning and extinction induce opposing changes in dendritic spine remodeling and somatic activity of layer 5 pyramidal neurons in the mouse motor cortex. Sci Rep 2019; 9:4619. [PMID: 30874589 PMCID: PMC6420657 DOI: 10.1038/s41598-019-40549-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/19/2019] [Indexed: 01/06/2023] Open
Abstract
Multiple brain regions including the amygdala and prefrontal cortex are crucial for modulating fear conditioning and extinction. The primary motor cortex is known to participate in the planning, control, and execution of voluntary movements. Whether and how the primary motor cortex is involved in modulating freezing responses related to fear conditioning and extinction remains unclear. Here we show that inactivation of the mouse primary motor cortex impairs both the acquisition and extinction of freezing responses induced by auditory-cued fear conditioning. Fear conditioning significantly increases the elimination of dendritic spines on apical dendrites of layer 5 pyramidal neurons in the motor cortex. These eliminated spines are further apart from each other than expected from random distribution along dendrites. On the other hand, fear extinction causes the formation of new spines that are located near the site of spines eliminated previously after fear conditioning. We further show that fear conditioning decreases and fear extinction increases somatic activities of layer 5 pyramidal neurons in the motor cortex respectively. Taken together, these findings indicate fear conditioning and extinction induce opposing changes in synaptic connections and somatic activities of layer 5 pyramidal neurons in the primary motor cortex, a cortical region important for the acquisition and extinction of auditory-cued conditioned freezing responses.
Collapse
|
44
|
Concina G, Renna A, Grosso A, Sacchetti B. The auditory cortex and the emotional valence of sounds. Neurosci Biobehav Rev 2019; 98:256-264. [DOI: 10.1016/j.neubiorev.2019.01.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 12/21/2022]
|
45
|
Laminar profile of task-related plasticity in ferret primary auditory cortex. Sci Rep 2018; 8:16375. [PMID: 30401927 PMCID: PMC6219524 DOI: 10.1038/s41598-018-34739-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 10/22/2018] [Indexed: 11/23/2022] Open
Abstract
Rapid task-related plasticity is a neural correlate of selective attention in primary auditory cortex (A1). Top-down feedback from higher-order cortex may drive task-related plasticity in A1, characterized by enhanced neural representation of behaviorally meaningful sounds during auditory task performance. Since intracortical connectivity is greater within A1 layers 2/3 (L2/3) than in layers 4–6 (L4–6), we hypothesized that enhanced representation of behaviorally meaningful sounds might be greater in A1 L2/3 than L4–6. To test this hypothesis and study the laminar profile of task-related plasticity, we trained 2 ferrets to detect pure tones while we recorded laminar activity across a 1.8 mm depth in A1. In each experiment we analyzed high-gamma local field potentials (LFPs) and multi-unit spiking in response to identical acoustic stimuli during both passive listening and active task performance. We found that neural responses to auditory targets were enhanced during task performance, and target enhancement was greater in L2/3 than in L4–6. Spectrotemporal receptive fields (STRFs) computed from both high-gamma LFPs and multi-unit spiking showed similar increases in auditory target selectivity, also greatest in L2/3. Our results suggest that activity within intracortical networks plays a key role in the underlying neural mechanisms of selective attention.
Collapse
|
46
|
Jose R, Santen L, Shaebani MR. Trapping in and Escape from Branched Structures of Neuronal Dendrites. Biophys J 2018; 115:2014-2025. [PMID: 30366628 DOI: 10.1016/j.bpj.2018.09.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 09/20/2018] [Accepted: 09/26/2018] [Indexed: 10/28/2022] Open
Abstract
We present a coarse-grained model for stochastic transport of noninteracting chemical signals inside neuronal dendrites and show how first-passage properties depend on the key structural factors affected by neurodegenerative disorders or aging: the extent of the tree, the topological bias induced by segmental decrease of dendrite diameter, and the trapping probabilities in biochemical cages and growth cones. We derive an exact expression for the distribution of first-passage times, which follows a universal exponential decay in the long-time limit. The asymptotic mean first-passage time exhibits a crossover from power-law to exponential scaling upon reducing the topological bias. We calibrate the coarse-grained model parameters and obtain the variation range of the mean first-passage time when the geometrical characteristics of the dendritic structure evolve during the course of aging or neurodegenerative disease progression (a few disorders for which clear trends for the pathological changes of dendritic structure have been reported in the literature are chosen and studied). We prove the validity of our analytical approach under realistic fluctuations of structural parameters by comparison to the results of Monte Carlo simulations. Moreover, by constructing local structural irregularities, we analyze the resulting influence on transport of chemical signals and formation of heterogeneous density patterns. Because neural functions rely on chemical signal transmission to a large extent, our results open the possibility of establishing a direct link between the disease progression and neural functions.
Collapse
Affiliation(s)
- Robin Jose
- Department of Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Ludger Santen
- Department of Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - M Reza Shaebani
- Department of Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany.
| |
Collapse
|
47
|
Axonal plasticity associated with perceptual learning in adult macaque primary visual cortex. Proc Natl Acad Sci U S A 2018; 115:10464-10469. [PMID: 30262651 DOI: 10.1073/pnas.1812932115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Perceptual learning is associated with changes in the functional properties of neurons even in primary sensory areas. In macaque monkeys trained to perform a contour detection task, we have observed changes in contour-related facilitation of neuronal responses in primary visual cortex that track their improvement in performance on a contour detection task. We have previously explored the anatomical substrate of experience-dependent changes in the visual cortex based on a retinal lesion model, where we find sprouting and pruning of the axon collaterals in the cortical lesion projection zone. Here, we attempted to determine whether similar changes occur under normal visual experience, such as that associated with perceptual learning. We labeled the long-range horizontal connections in visual cortex by virally mediated transfer of genes expressing fluorescent probes, which enabled us to do longitudinal two-photon imaging of axonal arbors over the period during which animals improve in contour detection performance. We found that there are substantial changes in the axonal arbors of neurons in cortical regions representing the trained part of the visual field, with sprouting of new axon collaterals and pruning of preexisting axon collaterals. Our findings indicate that changes in the structure of axonal arbors are part of the circuit-level mechanism of perceptual learning, and further support the idea that the learned information is encoded at least in part in primary visual cortex.
Collapse
|
48
|
Mongillo G, Rumpel S, Loewenstein Y. Inhibitory connectivity defines the realm of excitatory plasticity. Nat Neurosci 2018; 21:1463-1470. [PMID: 30224809 DOI: 10.1038/s41593-018-0226-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/30/2018] [Indexed: 12/19/2022]
Abstract
Recent experiments demonstrate substantial volatility of excitatory connectivity in the absence of any learning. This challenges the hypothesis that stable synaptic connections are necessary for long-term maintenance of acquired information. Here we measure ongoing synaptic volatility and use theoretical modeling to study its consequences on cortical dynamics. We show that in the balanced cortex, patterns of neural activity are primarily determined by inhibitory connectivity, despite the fact that most synapses and neurons are excitatory. Similarly, we show that the inhibitory network is more effective in storing memory patterns than the excitatory one. As a result, network activity is robust to ongoing volatility of excitatory synapses, as long as this volatility does not disrupt the balance between excitation and inhibition. We thus hypothesize that inhibitory connectivity, rather than excitatory, controls the maintenance and loss of information over long periods of time in the volatile cortex.
Collapse
Affiliation(s)
- Gianluigi Mongillo
- Centre National de la Recherche Scientifique (CNRS), Paris, France. .,Centre de Neurophysique, Physiologie et Pathologie (CNPP), Université Descartes, Paris, France.
| | - Simon Rumpel
- Institute of Physiology, Focus Program Translational Neuroscience, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Yonatan Loewenstein
- Department of Neurobiology, the Federmann Center for the Study of Rationality and the Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem, Israel.
| |
Collapse
|
49
|
Fear extinction reverses dendritic spine formation induced by fear conditioning in the mouse auditory cortex. Proc Natl Acad Sci U S A 2018; 115:9306-9311. [PMID: 30150391 DOI: 10.1073/pnas.1801504115] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Fear conditioning-induced behavioral responses can be extinguished after fear extinction. While fear extinction is generally thought to be a form of new learning, several lines of evidence suggest that neuronal changes associated with fear conditioning could be reversed after fear extinction. To better understand how fear conditioning and extinction modify synaptic circuits, we examined changes of postsynaptic dendritic spines of layer V pyramidal neurons in the mouse auditory cortex over time using transcranial two-photon microscopy. We found that auditory-cued fear conditioning induced the formation of new dendritic spines within 2 days. The survived new spines induced by fear conditioning with one auditory cue were clustered within dendritic branch segments and spatially segregated from new spines induced by fear conditioning with a different auditory cue. Importantly, fear extinction preferentially caused the elimination of newly formed spines induced by fear conditioning in an auditory cue-specific manner. Furthermore, after fear extinction, fear reconditioning induced reformation of new dendritic spines in close proximity to the sites of new spine formation induced by previous fear conditioning. These results show that fear conditioning, extinction, and reconditioning induce cue- and location-specific dendritic spine remodeling in the auditory cortex. They also suggest that changes of synaptic connections induced by fear conditioning are reversed after fear extinction.
Collapse
|
50
|
Alexander BH, Barnes HM, Trimmer E, Davidson AM, Ogola BO, Lindsey SH, Mostany R. Stable Density and Dynamics of Dendritic Spines of Cortical Neurons Across the Estrous Cycle While Expressing Differential Levels of Sensory-Evoked Plasticity. Front Mol Neurosci 2018; 11:83. [PMID: 29615867 PMCID: PMC5864847 DOI: 10.3389/fnmol.2018.00083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/01/2018] [Indexed: 12/11/2022] Open
Abstract
Periodic oscillations of gonadal hormone levels during the estrous cycle exert effects on the female brain, impacting cognition and behavior. While previous research suggests that changes in hormone levels across the cycle affect dendritic spine dynamics in the hippocampus, little is known about the effects on cortical dendritic spines and previous studies showed contradictory results. In this in vivo imaging study, we investigated the impact of the estrous cycle on the density and dynamics of dendritic spines of pyramidal neurons in the primary somatosensory cortex of mice. We also examined if the induction of synaptic plasticity during proestrus, estrus, and metestrus/diestrus had differential effects on the degree of remodeling of synapses in this brain area. We used chronic two-photon excitation (2PE) microscopy during steady-state conditions and after evoking synaptic plasticity by whisker stimulation at the different stages of the cycle. We imaged apical dendritic tufts of layer 5 pyramidal neurons of naturally cycling virgin young female mice. Spine density, turnover rate (TOR), survival fraction, morphology, and volume of mushroom spines remained unaltered across the estrous cycle, and the values of these parameters were comparable with those of young male mice. However, while whisker stimulation of female mice during proestrus and estrus resulted in increases in the TOR of spines (74.2 ± 14.9% and 75.1 ± 12.7% vs. baseline, respectively), sensory-evoked plasticity was significantly lower during metestrus/diestrus (32.3 ± 12.8%). In males, whisker stimulation produced 46.5 ± 20% increase in TOR compared with baseline—not significantly different from female mice at any stage of the cycle. These results indicate that, while steady-state density and dynamics of dendritic spines of layer 5 pyramidal neurons in the primary somatosensory cortex of female mice are constant during the estrous cycle, the susceptibility of these neurons to sensory-evoked structural plasticity may be dependent on the stage of the cycle. Since dendritic spines are more plastic during proestrus and estrus than during metestrus/diestrus, certain stages of the cycle could be more suitable for forms of memory requiring de novo formation and elimination of spines and other stages for forms of memory where retention and/or repurposing of already existing synaptic connections is more pertinent.
Collapse
Affiliation(s)
- Bailin H Alexander
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States
| | - Heather M Barnes
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States.,Neuroscience Program, Brain Institute, Tulane University, New Orleans, LA, United States
| | - Emma Trimmer
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States
| | - Andrew M Davidson
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States.,Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, United States
| | - Benard O Ogola
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States
| | - Sarah H Lindsey
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States.,Brain Institute, Tulane University, New Orleans, LA, United States
| | - Ricardo Mostany
- Department of Pharmacology, Tulane University School of Medicine, Tulane University, New Orleans, LA, United States.,Brain Institute, Tulane University, New Orleans, LA, United States
| |
Collapse
|