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Contreras MP, Mendez M, Shan X, Fechner J, Sawangjit A, Born J, Inostroza M. Context memory formed in medial prefrontal cortex during infancy enhances learning in adulthood. Nat Commun 2024; 15:2475. [PMID: 38509099 PMCID: PMC10954687 DOI: 10.1038/s41467-024-46734-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/06/2024] [Indexed: 03/22/2024] Open
Abstract
Adult behavior is commonly thought to be shaped by early-life experience, although episodes experienced during infancy appear to be forgotten. Exposing male rats during infancy to discrete spatial experience we show that these rats in adulthood are significantly better at forming a spatial memory than control rats without such infantile experience. We moreover show that the adult rats' improved spatial memory capability is mainly based on memory for context information during the infantile experiences. Infantile spatial experience increased c-Fos activity at memory testing during adulthood in the prelimbic medial prefrontal cortex (mPFC), but not in the hippocampus. Inhibiting prelimbic mPFC at testing during adulthood abolished the enhancing effect of infantile spatial experience on learning. Adult spatial memory capability only benefitted from spatial experience occurring during the sensitive period of infancy, but not when occurring later during childhood, and when sleep followed the infantile experience. In conclusion, the infantile brain, by a sleep-dependent mechanism, favors consolidation of memory for the context in which episodes are experienced. These representations comprise mPFC regions and context-dependently facilitate learning in adulthood.
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Affiliation(s)
- María P Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
- Leibniz-Institute of Neurobiology, Magdeburg, Germany
| | - Marta Mendez
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijoo, Oviedo, Spain
| | - Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - Julia Fechner
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
- Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
- German Center for Diabetes Research (DZD)-Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich (IDM) at the University Tübingen, Tübingen, Germany.
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
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Shan X, Contreras MP, Sawangjit A, Dimitrov S, Born J, Inostroza M. Rearing is critical for forming spatial representations in pre-weanling rats. Behav Brain Res 2023; 452:114545. [PMID: 37321311 DOI: 10.1016/j.bbr.2023.114545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 06/17/2023]
Abstract
Rearing, i.e., standing on the hind limbs in an upright posture, is part of a rat's innate exploratory motor program. Here, we examined in developing rats whether rearing is critical for the pup's capability to form spatial representations based on distal environmental cues. Pups (male) were tested at PD18, i.e., the first day they typically exhibit stable rearing, on a spatial habituation paradigm comprising a Familiarization session (with the pup exposed to an arena with a specific configuration of distal cues) followed, 3 h later, by a Test session where the pups were either re-exposed to the identical distal cue configuration (NoChange) or a changed configuration (DistalChange). In Experiment 1, rearing activity (rearing events, duration) decreased from Familiarization to Test in the NoChange pups but, remained elevated in the DistalChange group indicating that these pups recognized the distal novelty. Recognition of distal novelty was associated with increased c-Fos expression in hippocampal and medial prefrontal cortex (mPFC) areas, compared with NoChange pups. Analysis of GAD67+ cells suggested a parallel increase in excitation and inhibition specifically in prelimbic mPFC networks in response to distal cue changes. In Experiment 2, the pups were mechanically prevented from rearing while still seeing the distal cues during Familiarization. Rearing activity in the Test session of these pups did not differ between groups that were or were not exposed to a changed distal cue configuration at Test. The findings evidence a critical role of rearing for the emergence of allocentric representations integrating distal space during early development.
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Affiliation(s)
- Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - María Paz Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Stoyan Dimitrov
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Institute for Diabetes Research & Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Germany; Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; German Center for Mental Health (DZPG), Germany.
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
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Liu J, Dimitrov S, Sawangjit A, Born J, Ehrlich I, Hallschmid M. Short-term high-fat feeding induces a reversible net decrease in synaptic AMPA receptors in the hypothalamus. J Nutr Biochem 2021; 87:108516. [PMID: 33022406 DOI: 10.1016/j.jnutbio.2020.108516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 07/09/2020] [Accepted: 09/11/2020] [Indexed: 01/05/2023]
Abstract
Dietary obesity compromises brain function, but the effects of high-fat food on synaptic transmission in hypothalamic networks, as well as their potential reversibility, are yet to be fully characterized. We investigated the impact of high-fat feeding on a hallmark of synaptic plasticity, i.e., the expression of glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) that contain the subunits GluA1 and GluA2, in hypothalamic and cortical synaptoneurosomes of male rats. In the main experiment (experiment 1), three days, but not one day of high-fat diet (HFD) decreased the levels of AMPAR GluA1 and GluA2 subunits, as well as GluA1 phosphorylation at Ser845, in hypothalamus but not cortex. In experiment 2, we compared the effects of the three-day HFD with those a three-day HFD followed by four recovery days of normal chow. This experiment corroborated the suppressive effect of high-fat feeding on hypothalamic but not cortical AMPAR GluA1, GluA2, and GluA1 phosphorylation at Ser845, and indicated that the effects are reversed by normal-chow feeding. High-fat feeding generally increased energy intake, body weight, and serum concentrations of insulin, leptin, free fatty acids, and corticosterone; only the three-day HFD increased wakefulness assessed via video analysis. Results indicate a reversible down-regulation of hypothalamic glutamatergic synaptic strength in response to short-term high-fat feeding. Preceding the manifestation of obesity, this rapid change in glutamatergic neurotransmission may underlie counter-regulatory efforts to prevent excess body weight gain, and therefore, represent a new target of interventions to improve metabolic control.
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Affiliation(s)
- Jianfeng Liu
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Stoyan Dimitrov
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Tübingen, Germany
| | - Ingrid Ehrlich
- Hertie Institute for Clinical Brain Research and Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; Department of Neurobiology, Institute for Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Manfred Hallschmid
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Tübingen, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Tübingen, Germany.
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Sawangjit A, Oyanedel CN, Niethard N, Born J, Inostroza M. Deepened sleep makes hippocampal spatial memory more persistent. Neurobiol Learn Mem 2020; 173:107245. [DOI: 10.1016/j.nlm.2020.107245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/28/2020] [Accepted: 05/02/2020] [Indexed: 12/28/2022]
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Oyanedel CN, Sawangjit A, Born J, Inostroza M. Sleep-dependent consolidation patterns reveal insights into episodic memory structure. Neurobiol Learn Mem 2018; 160:67-72. [PMID: 29783060 DOI: 10.1016/j.nlm.2018.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Abstract
Episodic memory formation is considered a genuinely hippocampal function. Its study in rodents has relied on two different task paradigms, i.e. the so called "what-where-when" (WW-When) task and "what-where-which" (WW-Which) task. The WW-When task aims to assess the memory for an episode as an event bound into its context defined by spatial and distinct temporal information, the WW-Which task lacks the temporal component and introduces, instead, an "occasion setter" marking the broader contextual configuration in which the event occurred. Whether both tasks measure episodic memory in an equivalent manner in terms of recollection has been controversially discussed. Here, we compared in two groups of rats the consolidating effects of sleep on episodic-like memory between both task paradigms. Sampling and test phases were separated by a 90-min morning retention interval which did or did not allow for spontaneous sleep. Results show that sleep is crucial for the consolidation of the memory on both tasks. However, consolidating effects of sleep were stronger for the WW-Which than WW-When task. Comparing performance during the post-sleep test phase revealed that WW-When memory only gradually emerged during the 3-min test period whereas WW-Which memory was readily expressed already from the first minute onward. Separate analysis of the temporal and spatial components of WW-When performance showed that the delayed episodic memory on this task originated from the temporal component which also did not emerge until the third minute of the test phase, whereas the spatial component already showed up in the first minute. In conclusion, sleep differentially affects consolidation on the two episodic-like memory tasks, with the delayed expression of WW-When memory after sleep resulting from preferential coverage of temporal aspects by this task.
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Affiliation(s)
- Carlos N Oyanedel
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany.
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
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Sawangjit A, Kelemen E, Born J, Inostroza M. Sleep Enhances Recognition Memory for Conspecifics as Bound into Spatial Context. Front Behav Neurosci 2017; 11:28. [PMID: 28270755 PMCID: PMC5319304 DOI: 10.3389/fnbeh.2017.00028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/07/2017] [Indexed: 12/21/2022] Open
Abstract
Social memory refers to the fundamental ability of social species to recognize their conspecifics in quite different contexts. Sleep has been shown to benefit consolidation, especially of hippocampus-dependent episodic memory whereas effects of sleep on social memory are less well studied. Here, we examined the effect of sleep on memory for conspecifics in rats. To discriminate interactions between the consolidation of social memory and of spatial context during sleep, adult Long Evans rats performed on a social discrimination task in a radial arm maze. The Learning phase comprised three 10-min sampling sessions in which the rats explored a juvenile rat presented at a different arm of the maze in each session. Then the rats were allowed to sleep (n = 18) or stayed awake (n = 18) for 120 min. During the following 10-min Test phase, the familiar juvenile rat (of the Learning phase) was presented along with a novel juvenile rat, each rat at an opposite arm of the maze. Significant social recognition memory, as indicated by preferential exploration of the novel over the familiar conspecific, occurred only after post-learning sleep, but not after wakefulness. Sleep, compared with wakefulness, significantly enhanced social recognition during the first minute of the Test phase. However, memory expression depended on the spatial configuration: Significant social recognition memory emerged only after sleep when the rat encountered the novel conspecific at a place different from that of the familiar juvenile in the last sampling session before sleep. Though unspecific retrieval-related effects cannot entirely be excluded, our findings suggest that sleep, rather than independently enhancing social and spatial aspects of memory, consolidates social memory by acting on an episodic representation that binds the memory of the conspecific together with the spatial context in which it was recently encountered.
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Affiliation(s)
- Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen Tübingen, Germany
| | - Eduard Kelemen
- Institute of Medical Psychology and Behavioral Neurobiology, University of TübingenTübingen, Germany; National Institute of Mental HealthKlecany, Czechia
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of TübingenTübingen, Germany; German Center for Diabetes Research (DZD), Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen (IDM)Tübingen, Germany; Centre for Integrative Neuroscience, University of TübingenTübingen, Germany
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of TübingenTübingen, Germany; Departamento de Psicología, Universidad de ChileSantiago, Chile
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