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Liu P, Gao C, Wu J, Wu T, Zhang Y, Liu C, Sun C, Li A. Negative valence encoding in the lateral entorhinal cortex during aversive olfactory learning. Cell Rep 2023; 42:113204. [PMID: 37804511 DOI: 10.1016/j.celrep.2023.113204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 10/09/2023] Open
Abstract
Olfactory learning is widely regarded as a substrate for animal survival. The exact brain areas involved in olfactory learning and how they function at various stages during learning remain elusive. Here, we investigate the role of the lateral entorhinal cortex (LEC) and the posterior piriform cortex (PPC), two important olfactory areas, in aversive olfactory learning. We find that the LEC is involved in the acquisition of negative odor value during olfactory fear conditioning, whereas the PPC is involved in the memory-retrieval phase. Furthermore, inhibition of LEC CaMKIIα+ neurons affects fear encoding, fear memory recall, and PPC responses to a conditioned odor. These findings provide direct evidence for the involvement of LEC CaMKIIα+ neurons in negative valence encoding.
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Affiliation(s)
- Penglai Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Cheng Gao
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Jing Wu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Tingting Wu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Ying Zhang
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Changyu Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Changcheng Sun
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China.
| | - Anan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China.
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Kedrov AV, Mineyeva OA, Enikolopov GN, Anokhin KV. Involvement of Adult-born and Preexisting Olfactory Bulb and Dentate Gyrus Neurons in Single-trial Olfactory Memory Acquisition and Retrieval. Neuroscience 2019; 422:75-87. [DOI: 10.1016/j.neuroscience.2019.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/24/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022]
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3
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Courtiol E, Wilson DA. The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception. Perception 2016; 46:320-332. [PMID: 27687814 DOI: 10.1177/0301006616663216] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Olfactory perception and its underlying neural mechanisms are not fixed, but rather vary over time, dependent on various parameters such as state, task, or learning experience. In olfaction, one of the primary sensory areas beyond the olfactory bulb is the piriform cortex. Due to an increasing number of functions attributed to the piriform cortex, it has been argued to be an associative cortex rather than a simple primary sensory cortex. In fact, the piriform cortex plays a key role in creating olfactory percepts, helping to form configural odor objects from the molecular features extracted in the nose. Moreover, its dynamic interactions with other olfactory and nonolfactory areas are also critical in shaping the olfactory percept and resulting behavioral responses. In this brief review, we will describe the key role of the piriform cortex in the larger olfactory perceptual network, some of the many actors of this network, and the importance of the dynamic interactions among the piriform-trans-thalamic and limbic pathways.
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Affiliation(s)
- Emmanuelle Courtiol
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
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4
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Leitner FC, Melzer S, Lütcke H, Pinna R, Seeburg PH, Helmchen F, Monyer H. Spatially segregated feedforward and feedback neurons support differential odor processing in the lateral entorhinal cortex. Nat Neurosci 2016; 19:935-44. [PMID: 27182817 DOI: 10.1038/nn.4303] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 04/20/2016] [Indexed: 12/12/2022]
Abstract
The lateral entorhinal cortex (LEC) computes and transfers olfactory information from the olfactory bulb to the hippocampus. Here we established LEC connectivity to upstream and downstream brain regions to understand how the LEC processes olfactory information. We report that, in layer II (LII), reelin- and calbindin-positive (RE(+) and CB(+)) neurons constitute two major excitatory cell types that are electrophysiologically distinct and differentially connected. RE(+) neurons convey information to the hippocampus, while CB(+) neurons project to the olfactory cortex and the olfactory bulb. In vivo calcium imaging revealed that RE(+) neurons responded with higher selectivity to specific odors than CB(+) neurons and GABAergic neurons. At the population level, odor discrimination was significantly better for RE(+) than CB(+) neurons, and was lowest for GABAergic neurons. Thus, we identified in LII of the LEC anatomically and functionally distinct neuronal subpopulations that engage differentially in feedforward and feedback signaling during odor processing.
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Affiliation(s)
- Frauke C Leitner
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University, Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Sarah Melzer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University, Heidelberg, Germany
| | - Henry Lütcke
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Roberta Pinna
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University, Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter H Seeburg
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Fritjof Helmchen
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University, Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
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5
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Abstract
How sensory information is processed within olfactory cortices is unclear. Here, we examined long-range circuit wiring between different olfactory cortical regions of acute mouse brain slices using a channelrhodopsin-2 (ChR2)-based neuronal targeting approach. Our results provide detailed information regarding the synaptic properties of the reciprocal long-range monosynaptic glutamatergic projections (LRMGP) between and within anterior piriform cortex (aPC), posterior piriform cortex (pPC), and lateral entorhinal cortex (LEC), thereby creating a long-range inter- and intracortical circuit diagrams at the level of synapses and single cortical neurons. Our results reveal the following information regarding hierarchical intra- and intercortical organizations: (i) there is massive bottom-up (i.e., rostral-caudal) excitation within the LRMGP accompanied with strong feedforward (FF) inhibition; (ii) there are convergent FF connections onto LEC from both aPC and pPC; (iii) feedback (FB) intercortical connections are weak with a significant fraction of presumptive silent synapses; and (iv) intra and intercortical long-range connections lack layer specificity and their innervation of interneurons are stronger than neighboring pyramidal neurons. The elucidation of the distinct hierarchical organization of long-range olfactory cortical circuits paves the way for further understanding of higher order cortical processing within the olfactory system.
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Affiliation(s)
- Weiguo Yang
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY Graduate Neuroscience Program, University of Wyoming, Laramie, WY
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY
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6
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Abstract
The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer's disease, Parkinson's disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity?
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Barbosa FF, Santos JR, Meurer YSR, Macêdo PT, Ferreira LMS, Pontes IMO, Ribeiro AM, Silva RH. Differential Cortical c-Fos and Zif-268 Expression after Object and Spatial Memory Processing in a Standard or Episodic-Like Object Recognition Task. Front Behav Neurosci 2013; 7:112. [PMID: 23986669 PMCID: PMC3749513 DOI: 10.3389/fnbeh.2013.00112] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 08/06/2013] [Indexed: 01/27/2023] Open
Abstract
Episodic memory reflects the capacity to recollect what, where, and when a specific event happened in an integrative manner. Animal studies have suggested that the medial temporal lobe and the medial pre-frontal cortex are important for episodic-like memory (ELM) formation. The goal of present study was to evaluate whether there are different patterns of expression of the immediate early genes c-Fos and Zif-268 in these cortical areas after rats are exposed to object recognition (OR) tasks with different cognitive demands. Male rats were randomly assigned to five groups: home cage control, empty open field (CTR-OF), open field with one object (CTR-OF + Obj), novel OR task, and ELM task and were killed 1 h after the last behavioral procedure. Rats were able to discriminate the objects in the OR task. In the ELM task, rats showed spatial (but not temporal) discrimination of the objects. We found an increase in the c-Fos expression in the dorsal dentate gyrus (DG) and in the perirhinal cortex (PRh) in the OR and ELM groups. The OR group also presented an increase of c-Fos expression in the medial prefrontal cortex (mPFC). Additionally, the OR and ELM groups had increased expression of Zif-268 in the mPFC. Moreover, Zif-268 was increased in the dorsal CA1 and PRh only in the ELM group. In conclusion, the pattern of activation was different in tasks with different cognitive demands. Accordingly, correlation tests suggest the engagement of different neural networks in the tasks used. Specifically, perirhinal-DG co-activation was detected after the what-where memory retrieval, but not after the novel OR task. Both regions correlated with the respective behavioral outcome. These findings can be helpful in the understanding of the neural networks underlying memory tasks with different cognitive demands.
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Affiliation(s)
- Flávio Freitas Barbosa
- Memory and Cognition Studies Laboratory, Department of Psychology, Federal University of Paraíba, João Pessoa, Brazil
| | - José Ronaldo Santos
- Laboratory of Behavioral Neurobiology, Department of Biology, Federal University of Sergipe, São Cristóvão, Brazil
| | | | - Priscila Tavares Macêdo
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Luane M. Stamatto Ferreira
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Isabella M. Oliveira Pontes
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Alessandra Mussi Ribeiro
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Regina Helena Silva
- Memory Studies Laboratory, Department of Physiology, Federal University of Rio Grande do Norte, Natal, Brazil
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Chapuis J, Cohen Y, He X, Zhang Z, Jin S, Xu F, Wilson DA. Lateral entorhinal modulation of piriform cortical activity and fine odor discrimination. J Neurosci 2013; 33:13449-59. [PMID: 23946403 PMCID: PMC3742931 DOI: 10.1523/jneurosci.1387-13.2013] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/09/2013] [Accepted: 07/15/2013] [Indexed: 11/21/2022] Open
Abstract
The lateral entorhinal cortex (LEC) receives direct input from olfactory bulb mitral cells and piriform cortical pyramidal cells and is the gateway for olfactory input to the hippocampus. However, the LEC also projects back to the piriform cortex and olfactory bulb. Activity in the LEC is shaped by input from the perirhinal cortices, hippocampus, and amygdala, and thus could provide a rich contextual modulation of cortical odor processing. The present study further explored LEC feedback to anterior piriform cortex by examining how LEC top-down input modulates anterior piriform cortex odor evoked activity in rats. Retrograde viral tracing confirmed rich LEC projections to both the olfactory bulb and piriform cortices. In anesthetized rats, reversible lesions of the ipsilateral LEC increased anterior piriform cortical single-unit spontaneous activity. In awake animals performing an odor discrimination task, unilateral LEC reversible lesions enhanced ipsilateral piriform cortical local field potential oscillations during odor sampling, with minimal impact on contralateral activity. Bilateral LEC reversible lesions impaired discrimination performance on a well learned, difficult odor discrimination task, but had no impact on a well learned simple odor discrimination task. The simple discrimination task was impaired by bilateral reversible lesions of the anterior piriform cortex. Given the known function of LEC in working memory and multisensory integration, these results suggest it may serve as a powerful top-down modulator of olfactory cortical function and odor perception. Furthermore, the results provide potential insight into how neuropathology in the entorhinal cortex could contribute to early olfactory deficits seen in Alzheimer's disease.
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Affiliation(s)
- Julie Chapuis
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962
- Child and Adolescent Psychiatry, New York University Langone School of Medicine, New York, New York 10016
| | - Yaniv Cohen
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962
- Child and Adolescent Psychiatry, New York University Langone School of Medicine, New York, New York 10016
| | - Xiaobin He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing, 100049, China, and
| | - Zhijan Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
- Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Sen Jin
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
| | - Fuqiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences, Wuhan 430071, China
- Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China
- University of Chinese Academy of Sciences, Beijing, 100049, China, and
| | - Donald A. Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962
- Child and Adolescent Psychiatry, New York University Langone School of Medicine, New York, New York 10016
- Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China
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9
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Xu W, Wilson DA. Odor-evoked activity in the mouse lateral entorhinal cortex. Neuroscience 2012; 223:12-20. [PMID: 22871522 PMCID: PMC3455128 DOI: 10.1016/j.neuroscience.2012.07.067] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
The entorhinal cortex is a brain area with multiple reciprocal connections to the hippocampus, amygdala, perirhinal cortex, olfactory bulb and piriform cortex. As such, it is thought to play a large role in the olfactory memory process. The present study is the first to compare lateral entorhinal and anterior piriform cortex odor-evoked single-unit and local field potential activity in mouse. Recordings were made in urethane-anesthetized mice that were administered a range of three pure odors and three overlapping odor mixtures. Results show that spontaneous as well as odor-evoked unit activity was lower in lateral entorhinal versus piriform cortex. In addition, units in lateral entorhinal cortex were responsive to a more restricted set of odors compared to piriform. Conversely, odor-evoked power change in local field potential activity was greater in the lateral entorhinal cortex in the theta band than in piriform. The highly odor-specific and restricted firing in lateral entorhinal cortex suggests that it may play a role in modulating odor-specific, experience- and state-dependent olfactory coding.
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Affiliation(s)
- W Xu
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY 10962, USA.
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Paban V, Chambon C, Farioli F, Alescio-Lautier B. Gene regulation in the rat prefrontal cortex after learning with or without cholinergic insult. Neurobiol Learn Mem 2011; 95:441-52. [PMID: 21345373 DOI: 10.1016/j.nlm.2011.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/25/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
Abstract
The prefrontal cortex is essential for a wide variety of higher functions, including attention and memory. Cholinergic neurons are thought to be of prime importance in the modulation of these processes. Degeneration of forebrain cholinergic neurons has been linked to several neurological disorders. The present study was designed to identify genes and networks in rat prefrontal cortex that are associated with learning and cholinergic-loss-memory deficit. Affymetrix microarray technology was used to screen gene expression changes in rats submitted or not to 192 IgG-saporin immunolesion of cholinergic basal forebrain and trained in spatial/object novelty tasks. Results showed learning processes were associated with significant expression of genes, which were organized in several clusters of highly correlated genes and would be involved in biological processes such as intracellular signaling process, transcription regulation, and filament organization and axon guidance. Memory loss following cortical cholinergic deafferentation was associated with significant expression of genes belonging to only one clearly delineated cluster and would be involved in biological processes related to cytoskeleton organization and proliferation, and glial and vascular remodeling, i.e., in processes associated with brain repair after injury.
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Affiliation(s)
- Véronique Paban
- Université d'Aix-Marseille I, Laboratoire de Neurosciences Intégratives et Adaptatives, UMR/CNRS 6149, 3 Place Victor Hugo, 13331 Marseille Cedex 03, France.
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11
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Majkutewicz I, Cecot T, Jerzemowska G, Myślińska D, Plucińska K, Trojniar W, Wrona D. Lesion of the ventral tegmental area amplifies stimulation-induced Fos expression in the rat brain. Brain Res 2010; 1320:95-105. [PMID: 20079346 DOI: 10.1016/j.brainres.2010.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 12/31/2009] [Accepted: 01/05/2010] [Indexed: 11/17/2022]
Abstract
Unilateral lesions of the ventral tegmental area (VTA), the key structure of the mesolimbic system, facilitate behavioral responses induced by electrical stimulation of the VTA in the contralateral hemisphere. In search of the neuronal mechanism behind this phenomenon, Fos expression was used to measure neuronal activation of the target mesolimbic structures in rats subjected to unilateral electrocoagulation and simultaneously to contralateral electrical stimulation of the VTA (L/S group). These were compared to the level of mesolimbic activation after unilateral electrocoagulation of the VTA (L group), unilateral electrical stimulation of the VTA (S group) and bilateral electrode implantation into the VTA in the sham (Sh) group. We found that unilateral stimulation of the VTA alone increased the density of Fos containing neurons in the ipsilateral mesolimbic target structures: nucleus accumbens, lateral septum and amygdala in comparison with the sham group. However, unilateral lesion of the VTA was devoid of effect in non-stimulated (L) rats and it significantly amplified the stimulation-induced Fos-immunoreactivity (L/S vs S group). Stimulation of the VTA performed after contralateral lesion (L/S) evoked strong bilateral induction of Fos expression in the mesolimbic structures involved in motivation and reward (nucleus accumbens and lateral septum) and the processing of the reinforcing properties of olfactory stimuli (anterior cortical amygdaloid nucleus) in parallel with facilitation of behavioral function measured as shortened latency of eating or exploration. Our data suggest that VTA lesion sensitizes mesolimbic system to stimuli by suppressing an inhibitory influence of brain areas afferenting the VTA.
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Affiliation(s)
- Irena Majkutewicz
- Department of Animal Physiology, University of Gdańsk, 24 Kładki St., 80-822 Gdańsk, Poland
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Dardou D, Datiche F, Cattarelli M. Does the olfactory cue activate the same brain network during aging in the rat after taste potentiated odor aversion retrieval? Neurobiol Learn Mem 2009; 93:137-50. [PMID: 19761859 DOI: 10.1016/j.nlm.2009.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 09/03/2009] [Accepted: 09/09/2009] [Indexed: 11/29/2022]
Abstract
Depending on the brain networks involved, aging is not accompanied by a general decrease in learning and memory capabilities. We demonstrated previously that learning and retrieval of taste potentiated odor aversion (TPOA) is preserved, and even slightly improved, in senescent rats showing some memory deficiencies in cognitive tasks (Dardou, Datiche, & Cattarelli, 2008). TPOA is a particular behavior in which the simultaneous presentation of odor and taste cues followed by a delayed visceral illness leads to a robust aversion towards both conditioned stimuli, which permits diet selection and animal survival. The present experiment was performed in order to investigate the stability or the evolution of the brain network underlying TPOA retrieval during aging. By using immunocytochemical detection of Fos and Egr1 proteins we mapped the cerebral activation induced by TPOA retrieval elicited by the odor presentation in the young, the adult and the senescent rats. The pattern of brain activation changed and the number of activated areas decreased with age. Nevertheless, the piriform cortex and the basolateral amygdala nucleus were always activated and seemed essential for TPOA retrieval. The hippocampus and the neocortical areas could have different implications in TPOA memory in relation to age. The patterns of expression of Fos and Egr1 were different, suggesting their differential involvement in TPOA retrieval. Data are discussed according to the possible roles of the brain areas studied and a model of schematic brain network subtending TPOA retrieval induced by the odor cue is proposed.
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Affiliation(s)
- David Dardou
- Centre Européen des Sciences du Goût, CNRS UMR 5170, 15 rue Hugues Picardet, 21000 Dijon, France.
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Coutureau E, Di Scala G. Entorhinal cortex and cognition. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:753-61. [PMID: 19376185 DOI: 10.1016/j.pnpbp.2009.03.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Accepted: 03/30/2009] [Indexed: 10/20/2022]
Abstract
Understanding the function of the entorhinal cortex (EC) has been an important subject over the years, not least because of its cortical intermediary to and from the hippocampus proper, and because of electrophysiological advances which have started to reveal the physiology in behaving animals. Clearly, a lot more needs to be done but is clear to date that EC is not merely a throughput station providing all hippocampal subfields with sensory information, but that processing within EC contributes significantly to attention, conditioning, event and spatial cognition possibly by compressing representations that overlap in time. These are transmitted to the hippocampus, where they are differentiated again and returned to EC. Preliminary evidence for such a role, but also their possible pitfalls are summarised.
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Affiliation(s)
- Etienne Coutureau
- Centre de Neurosciences Intégratives et Cognitives, UMR 5228 CNRS, Universités de Bordeaux 1 & 2, Avenue des Facultés, 33405 Talence, France
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Jacquot C, Croft AP, Prendergast MA, Mulholland P, Shaw SG, Little HJ. Effects of the glucocorticoid antagonist, mifepristone, on the consequences of withdrawal from long term alcohol consumption. Alcohol Clin Exp Res 2008; 32:2107-16. [PMID: 18828802 DOI: 10.1111/j.1530-0277.2008.00799.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Studies were carried out to test the hypothesis that administration of a glucocorticoid Type II receptor antagonist, mifepristone (RU38486), just prior to withdrawal from chronic alcohol treatment, would prevent the consequences of the alcohol consumption and withdrawal in mice. MATERIALS AND METHODS The effects of administration of a single intraperitoneal dose of mifepristone were examined on alcohol withdrawal hyperexcitability. Memory deficits during the abstinence phase were measured using repeat exposure to the elevated plus maze, the object recognition test, and the odor habituation/discrimination test. Neurotoxicity in the hippocampus and prefrontal cortex was examined using NeuN staining. RESULTS Mifepristone reduced, though did not prevent, the behavioral hyperexcitability seen in TO strain mice during the acute phase of alcohol withdrawal (4 hours to 8 hours after cessation of alcohol consumption) following chronic alcohol treatment via liquid diet. There were no alterations in anxiety-related behavior in these mice at 1 week into withdrawal, as measured using the elevated plus maze. However, changes in behavior during a second exposure to the elevated plus maze 1 week later were significantly reduced by the administration of mifepristone prior to withdrawal, indicating a reduction in the memory deficits caused by the chronic alcohol treatment and withdrawal. The object recognition test and the odor habituation and discrimination test were then used to measure memory deficits in more detail, at between 1 and 2 weeks after alcohol withdrawal in C57/BL10 strain mice given alcohol chronically via the drinking fluid. A single dose of mifepristone given at the time of alcohol withdrawal significantly reduced the memory deficits in both tests. NeuN staining showed no evidence of neuronal loss in either prefrontal cortex or hippocampus after withdrawal from chronic alcohol treatment. CONCLUSIONS The results suggest mifepristone may be of value in the treatment of alcoholics to reduce their cognitive deficits.
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Affiliation(s)
- Catherine Jacquot
- Department of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London, United Kingdom
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Albasser MM, Poirier GL, Warburton EC, Aggleton JP. Hippocampal lesions halve immediate-early gene protein counts in retrosplenial cortex: distal dysfunctions in a spatial memory system. Eur J Neurosci 2007; 26:1254-66. [PMID: 17767503 DOI: 10.1111/j.1460-9568.2007.05753.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present study examined whether hippocampal lesions disrupt retrosplenial cortex function. The immediate-early genesc-fos and zif268 provided markers of cellular activity, and their levels were compared in different cytoarchitectonic subregions (dysgranular, granular a and granular b) and different layers (superficial or deep) within retrosplenial cortex. Experiments 1-3 examined the impact of hippocampal lesions on retrosplenial cortex function, with the variations in protocol (e.g. lesion method, rat strain, behaviour prior to gene activity measurement) testing the generality of the findings. Experiment 1 showed that radio-frequency hippocampus lesions result in very striking losses of Fos and Zif268 activity in both superficial and deep laminae of all retrosplenial subregions. This pattern of results was repeated for Fos in experiments 2 and 3. Despite the loss of Fos and Zif268, there was no evidence of retrosplenial cortex atrophy as measured by Nissl counts (experiments 1-3) or NeuN-positive cell counts (experiment 3). Likewise, there was little evidence of any overt changes in cellular size, shape or appearance. The specificity of these hippocampal lesion effects was confirmed in experiment 4 as entorhinal cortex lesions did not change retrosplenial Fos levels. These results provide strong support for the notion that the retrosplenial cortex is unusually sensitive to deafferentation from some of its inputs, so that hippocampal damage might produce permanent 'covert pathology' in the retrosplenial cortex. Such dysfunctions could contribute to the pattern of cognitive changes associated with hippocampal lesions and also help to explain the functional interdependency of these two structures.
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Affiliation(s)
- Mathieu M Albasser
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff, CF10 3AT, UK
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Immunotoxic cholinergic lesions in the basal forebrain reverse the effects of entorhinal cortex lesions on conditioned odor aversion in the rat. Neurobiol Learn Mem 2007; 88:114-26. [DOI: 10.1016/j.nlm.2007.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 01/23/2007] [Accepted: 01/25/2007] [Indexed: 11/20/2022]
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Guilding C, Piggins HD. Challenging the omnipotence of the suprachiasmatic timekeeper: are circadian oscillators present throughout the mammalian brain? Eur J Neurosci 2007; 25:3195-216. [PMID: 17552989 DOI: 10.1111/j.1460-9568.2007.05581.x] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The suprachiasmatic nucleus of the hypothalamus (SCN) is the master circadian pacemaker or clock in the mammalian brain. Canonical theory holds that the output from this single, dominant clock is responsible for driving most daily rhythms in physiology and behaviour. However, important recent findings challenge this uniclock model and reveal clock-like activities in many neural and non-neural tissues. Thus, in addition to the SCN, a number of areas of the mammalian brain including the olfactory bulb, amygdala, lateral habenula and a variety of nuclei in the hypothalamus, express circadian rhythms in core clock gene expression, hormone output and electrical activity. This review examines the evidence for extra-SCN circadian oscillators in the mammalian brain and highlights some of the essential properties and key differences between brain oscillators. The demonstration of neural pacemakers outside the SCN has wide-ranging implications for models of the circadian system at a whole-organism level.
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Affiliation(s)
- Clare Guilding
- 3.614 Stopford Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Seillier A, Dieu Y, Herbeaux K, Di Scala G, Will B, Majchrzak M. Evidence for a critical role of entorhinal cortex at pre-exposure for latent inhibition disruption in rats. Hippocampus 2007; 17:220-6. [PMID: 17203462 DOI: 10.1002/hipo.20260] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Latent inhibition (LI), that is the decrease in conditioned response induced by the repeated nonreinforced pre-exposures to the to-be-conditioned stimulus, is disrupted by entorhinal cortex (EC) lesions. The mechanism involved in this disruption is unknown, and in particular the experimental stage (pre-exposure or conditioning) at which the integrity of EC is necessary has to be determined. The purpose of this study was to address this issue by using reversible inactivation of the EC by local micro-infusion of tetrodotoxin (TTX). TTX was infused either before the pre-exposure phase, before the conditioning phase, or before both phases. LI was unaffected in rats that received TTX before conditioning or before both pre-exposure and conditioning. In contrast, LI was disrupted in rats that received TTX before pre-exposure only. These results are discussed in the framework of LI models.
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Affiliation(s)
- A Seillier
- Laboratoire de Neurosciences Comportementales et Cognitives, FRE 2855, Strasbourg, France
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