1
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Trejo DH, Ciuparu A, da Silva PG, Velasquez CM, Rebouillat B, Gross MD, Davis MB, Muresan RC, Albeanu DF. Fast updating feedback from piriform cortex to the olfactory bulb relays multimodal reward contingency signals during rule-reversal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557267. [PMID: 37745564 PMCID: PMC10515864 DOI: 10.1101/2023.09.12.557267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
While animals readily adjust their behavior to adapt to relevant changes in the environment, the neural pathways enabling these changes remain largely unknown. Here, using multiphoton imaging, we investigated whether feedback from the piriform cortex to the olfactory bulb supports such behavioral flexibility. To this end, we engaged head-fixed mice in a multimodal rule-reversal task guided by olfactory and auditory cues. Both odor and, surprisingly, the sound cues triggered cortical bulbar feedback responses which preceded the behavioral report. Responses to the same sensory cue were strongly modulated upon changes in stimulus-reward contingency (rule reversals). The re-shaping of individual bouton responses occurred within seconds of the rule-reversal events and was correlated with changes in the behavior. Optogenetic perturbation of cortical feedback within the bulb disrupted the behavioral performance. Our results indicate that the piriform-to-olfactory bulb feedback carries reward contingency signals and is rapidly re-formatted according to changes in the behavioral context.
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Affiliation(s)
| | - Andrei Ciuparu
- Transylvanian Institute of Neuroscience, Cluj-Napoca, Romania
| | - Pedro Garcia da Silva
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address – Champalimaud Neuroscience Program, Lisbon, Portugal
| | - Cristina M. Velasquez
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address – University of Oxford, UK
| | - Benjamin Rebouillat
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address –École Normale Supérieure, Paris, France
| | | | | | - Raul C. Muresan
- Transylvanian Institute of Neuroscience, Cluj-Napoca, Romania
- STAR-UBB Institute, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Dinu F. Albeanu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- School for Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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2
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Gaeta G, Wilson DA. Reciprocal relationships between sleep and smell. Front Neural Circuits 2022; 16:1076354. [PMID: 36619661 PMCID: PMC9813672 DOI: 10.3389/fncir.2022.1076354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022] Open
Abstract
Despite major anatomical differences with other mammalian sensory systems, olfaction shares with those systems a modulation by sleep/wake states. Sleep modulates odor sensitivity and serves as an important regulator of both perceptual and associative odor memory. In addition, however, olfaction also has an important modulatory impact on sleep. Odors can affect the latency to sleep onset, as well as the quality and duration of sleep. Olfactory modulation of sleep may be mediated by direct synaptic interaction between the olfactory system and sleep control nuclei, and/or indirectly through odor modulation of arousal and respiration. This reciprocal interaction between sleep and olfaction presents novel opportunities for sleep related modulation of memory and perception, as well as development of non-pharmacological olfactory treatments of simple sleep disorders.
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Affiliation(s)
- Giuliano Gaeta
- Givaudan UK Limited, Health and Well-Being Centre of Excellence, Ashford, United Kingdom,Giuliano Gaeta,
| | - Donald A. Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States,Child and Adolescent Psychiatry, NYU School of Medicine, New York University, New York, NY, United States,*Correspondence: Donald A. Wilson,
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3
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Zhou P, Liu P, Zhang Y, Wang D, Li A. The Response Dynamics and Function of Cholinergic and GABAergic Neurons in the Basal Forebrain During Olfactory Learning. Front Cell Neurosci 2022; 16:911439. [PMID: 35966196 PMCID: PMC9363711 DOI: 10.3389/fncel.2022.911439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Modulation of neural circuits is essential for flexible sensory perception and decision-making in a changing environment. Cholinergic and GABAergic projections to the olfactory system from the horizontal limb of the diagonal band of Broca (HDB) in the basal forebrain are crucial for odor detection and olfactory learning. Although studies have demonstrated that HDB neurons respond during olfactory learning, how cholinergic and GABAergic neurons differ in their response dynamics and roles in olfactory learning remains unclear. In this study, we examined the response profiles of these two subpopulations of neurons during passive odor exposure and associative olfactory learning. We show that the excitatory responses in both cholinergic and GABAergic neurons tended to habituate during repeated passive odor exposure. However, while these habituated responses were also observed in GABAergic neurons during a go-go task, there was no such habituation in cholinergic neurons. Moreover, the responses to S+ and S− trials diverged in cholinergic neurons once mice learned a go/no-go task. Furthermore, the chemogenetic inactivation of cholinergic neurons in the HDB impaired odor discrimination. Together, these findings suggest that cholinergic neurons in the HDB reflect attention to positive reinforcement and may regulate odor discrimination via top–down inputs to the olfactory system.
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Affiliation(s)
| | | | | | | | - Anan Li
- *Correspondence: Dejuan Wang Anan Li
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4
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Manzini I, Schild D, Di Natale C. Principles of odor coding in vertebrates and artificial chemosensory systems. Physiol Rev 2021; 102:61-154. [PMID: 34254835 DOI: 10.1152/physrev.00036.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biological olfactory system is the sensory system responsible for the detection of the chemical composition of the environment. Several attempts to mimic biological olfactory systems have led to various artificial olfactory systems using different technical approaches. Here we provide a parallel description of biological olfactory systems and their technical counterparts. We start with a presentation of the input to the systems, the stimuli, and treat the interface between the external world and the environment where receptor neurons or artificial chemosensors reside. We then delineate the functions of receptor neurons and chemosensors as well as their overall I-O relationships. Up to this point, our account of the systems goes along similar lines. The next processing steps differ considerably: while in biology the processing step following the receptor neurons is the "integration" and "processing" of receptor neuron outputs in the olfactory bulb, this step has various realizations in electronic noses. For a long period of time, the signal processing stages beyond the olfactory bulb, i.e., the higher olfactory centers were little studied. Only recently there has been a marked growth of studies tackling the information processing in these centers. In electronic noses, a third stage of processing has virtually never been considered. In this review, we provide an up-to-date overview of the current knowledge of both fields and, for the first time, attempt to tie them together. We hope it will be a breeding ground for better information, communication, and data exchange between very related but so far little connected fields.
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Affiliation(s)
- Ivan Manzini
- Animal Physiology and Molecular Biomedicine, Justus-Liebig-University Gießen, Gießen, Germany
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University Medical Center, University of Göttingen, Göttingen, Germany
| | - Corrado Di Natale
- Department of Electronic Engineering, University of Rome Tor Vergata, Rome, Italy
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5
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Forest J, Chalençon L, Midroit M, Terrier C, Caillé I, Sacquet J, Benetollo C, Martin K, Richard M, Didier A, Mandairon N. Role of Adult-Born Versus Preexisting Neurons Born at P0 in Olfactory Perception in a Complex Olfactory Environment in Mice. Cereb Cortex 2021; 30:534-549. [PMID: 31216001 DOI: 10.1093/cercor/bhz105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 03/26/2019] [Accepted: 04/21/2019] [Indexed: 12/11/2022] Open
Abstract
Olfactory perceptual learning is defined as an improvement in the discrimination of perceptually close odorants after passive exposure to these odorants. In mice, simple olfactory perceptual learning involving the discrimination of two odorants depends on an increased number of adult-born neurons in the olfactory bulb, which refines the bulbar output. However, the olfactory environment is complex, raising the question of the adjustment of the bulbar network to multiple discrimination challenges. Perceptual learning of 1 to 6 pairs of similar odorants led to discrimination of all learned odor pairs. Increasing complexity did not increase adult-born neuron survival but enhanced the number of adult-born neurons responding to learned odorants and their spine density. Moreover, only complex learning induced morphological changes in neurons of the granule cell layer born during the first day of life (P0). Selective optogenetic inactivation of either population confirmed functional involvement of adult-born neurons regardless of the enrichment complexity, while preexisting neurons were required for complex discrimination only.
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Affiliation(s)
- Jérémy Forest
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Laura Chalençon
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Maëllie Midroit
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Claire Terrier
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Isabelle Caillé
- Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Centre National de la Recherche Scientifique, UMR8246, INSERM U1130, Institut de Biologie Paris Seine, Neuroscience Paris Seine, and Sorbonne Paris Cité, Université Paris Diderot-Paris 7, Paris, France
| | - Joëlle Sacquet
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Claire Benetollo
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Neurogenetic and Optogenetic Platform, University Lyon 1 and University of Lyon, Lyon F-69000, France
| | - Killian Martin
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Marion Richard
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Anne Didier
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Nathalie Mandairon
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
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6
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Oruro EM, Pardo GVE, Lucion AB, Calcagnotto ME, Idiart MAP. The maturational characteristics of the GABA input in the anterior piriform cortex may also contribute to the rapid learning of the maternal odor during the sensitive period. ACTA ACUST UNITED AC 2020; 27:493-502. [PMID: 33199474 PMCID: PMC7670864 DOI: 10.1101/lm.052217.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 09/27/2020] [Indexed: 11/25/2022]
Abstract
During the first ten postnatal days (P), infant rodents can learn olfactory preferences for novel odors if they are paired with thermo-tactile stimuli that mimic components of maternal care. After P10, the thermo-tactile pairing becomes ineffective for conditioning. The current explanation for this change in associative learning is the alteration in the norepinephrine (NE) inputs from the locus coeruleus (LC) to the olfactory bulb (OB) and the anterior piriform cortex (aPC). By combining patch-clamp electrophysiology and computational simulations, we showed in a recent work that a transitory high responsiveness of the OB-aPC circuit to the maternal odor is an alternative mechanism that could also explain early olfactory preference learning and its cessation after P10. That result relied solely on the maturational properties of the aPC pyramidal cells. However, the GABAergic system undergoes important changes during the same period. To address the importance of the maturation of the GABAergic system for early olfactory learning, we incorporated data from the GABA inputs, obtained from in vitro patch-clamp experiment in the aPC of rat pups aged P5–P7 reported here, to the model proposed in our previous publication. In the younger than P10 OB-aPC circuit with GABA synaptic input, the number of responsive aPC pyramidal cells to the conditioned maternal odor was amplified in 30% compared to the circuit without GABAergic input. When compared with the circuit with other younger than P10 OB-aPC circuit with adult GABAergic input profile, this amplification was 88%. Together, our results suggest that during the olfactory preference learning in younger than P10, the GABAergic synaptic input presumably acts by depolarizing the aPC pyramidal neurons in such a way that it leads to the amplification of the pyramidal neurons response to the conditioned maternal odor. Furthermore, our results suggest that during this developmental period, the aPC pyramidal cells themselves seem to resolve the apparent lack of GABAergic synaptic inhibition by a strong firing adaptation in response to increased depolarizing inputs.
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Affiliation(s)
- Enver Miguel Oruro
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Grace V E Pardo
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90035-003, Brazil.,Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil.,Centre for Interdisciplinary Science and Society Studies, Universidad de Ciencias y Humanidades, Los Olivos, Lima 15314, Peru.,Center for Biomedical Research, Universidad Andina del Cusco, San Jerónimo, Cuzco 08006, Peru
| | - Aldo Bolten Lucion
- Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil.,Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil
| | - Maria Elisa Calcagnotto
- Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Marco A P Idiart
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90050-170, Brazil
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7
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Cho C, Linster C. Experience enhances certainty about olfactory stimuli under bulbar cholinergic control. ACTA ACUST UNITED AC 2020; 27:414-417. [PMID: 32934093 PMCID: PMC7497109 DOI: 10.1101/lm.051854.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/26/2020] [Indexed: 11/25/2022]
Abstract
We present evidence that experience and cholinergic modulation in an early sensory network interact to improve certainty about olfactory stimuli. The data we present are in agreement with existing theoretical ideas about the functional role of acetylcholine but highlight the importance of early sensory networks in addition to cortical networks. We use a simple behavioral paradigm in mice which allows us to measure certainty about a stimulus via the response amplitude to a condition and novel stimuli. We conclude that additional learning increases certainty and that the slope of this relationship can be modulated by activation of muscarinic cholinergic receptors in the olfactory bulb.
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Affiliation(s)
- Christina Cho
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14850, USA
| | - Christiane Linster
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14850, USA
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8
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Böhm E, Brunert D, Rothermel M. Input dependent modulation of olfactory bulb activity by HDB GABAergic projections. Sci Rep 2020; 10:10696. [PMID: 32612119 PMCID: PMC7329849 DOI: 10.1038/s41598-020-67276-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/27/2020] [Indexed: 12/16/2022] Open
Abstract
Basal forebrain modulation of central circuits is associated with active sensation, attention, and learning. While cholinergic modulations have been studied extensively the effect of non-cholinergic basal forebrain subpopulations on sensory processing remains largely unclear. Here, we directly compare optogenetic manipulation effects of two major basal forebrain subpopulations on principal neuron activity in an early sensory processing area, i.e. mitral/tufted cells (MTCs) in the olfactory bulb. In contrast to cholinergic projections, which consistently increased MTC firing, activation of GABAergic fibers from basal forebrain to the olfactory bulb leads to differential modulation effects: while spontaneous MTC activity is mainly inhibited, odor-evoked firing is predominantly enhanced. Moreover, sniff-triggered averages revealed an enhancement of maximal sniff evoked firing amplitude and an inhibition of firing rates outside the maximal sniff phase. These findings demonstrate that GABAergic neuromodulation affects MTC firing in a bimodal, sensory-input dependent way, suggesting that GABAergic basal forebrain modulation could be an important factor in attention mediated filtering of sensory information to the brain.
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Affiliation(s)
- Erik Böhm
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany
| | - Daniela Brunert
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany
| | - Markus Rothermel
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany.
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9
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Nunez-Parra A, Cea-Del Rio CA, Huntsman MM, Restrepo D. The Basal Forebrain Modulates Neuronal Response in an Active Olfactory Discrimination Task. Front Cell Neurosci 2020; 14:141. [PMID: 32581716 PMCID: PMC7289987 DOI: 10.3389/fncel.2020.00141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/27/2020] [Indexed: 02/02/2023] Open
Abstract
Successful completion of sensory decision-making requires focusing on relevant stimuli, adequate signal/noise ratio for stimulus discrimination, and stimulus valence evaluation. Different brain regions are postulated to play a role in these computations; however, evidence suggests that sensory and decision-making circuits are required to interact through a common neuronal pathway to elicit a context-adequate behavioral response. Recently, the basal forebrain (BF) region has emerged as a good candidate, since its heterogeneous projecting neurons innervate most of the cortical mantle and sensory processing circuits modulating different aspects of the sensory decision-making process. Moreover, evidence indicates that the BF plays an important role in attention and in fast modulation of neuronal activity that enhance visual and olfactory sensory perception. Here, we study in awake mice the involvement of BF in initiation and completion of trials in a reward-driven olfactory detection task. Using tetrode recordings, we find that BF neurons (including cholinergics) are recruited during sensory discrimination, reward, and interestingly slightly before trial initiation in successful discrimination trials. The precue neuronal activity was correlated with animal performance, indicating that this circuit could play an important role in adaptive context-dependent behavioral responses.
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Affiliation(s)
- Alexia Nunez-Parra
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
| | - Christian A. Cea-Del Rio
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Molly M. Huntsman
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Diego Restrepo
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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10
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Imam N, Cleland TA. Rapid online learning and robust recall in a neuromorphic olfactory circuit. NAT MACH INTELL 2020; 2:181-191. [PMID: 38650843 PMCID: PMC11034913 DOI: 10.1038/s42256-020-0159-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 02/07/2020] [Indexed: 01/02/2023]
Abstract
We present a neural algorithm for the rapid online learning and identification of odourant samples under noise, based on the architecture of the mammalian olfactory bulb and implemented on the Intel Loihi neuromorphic system. As with biological olfaction, the spike timing-based algorithm utilizes distributed, event-driven computations and rapid (one-shot) online learning. Spike timing-dependent plasticity rules operate iteratively over sequential gamma-frequency packets to construct odour representations from the activity of chemosensor arrays mounted in a wind tunnel. Learned odourants then are reliably identified despite strong destructive interference. Noise resistance is further enhanced by neuromodulation and contextual priming. Lifelong learning capabilities are enabled by adult neurogenesis. The algorithm is applicable to any signal identification problem in which high-dimensional signals are embedded in unknown backgrounds.
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Affiliation(s)
- Nabil Imam
- Neuromorphic Computing Laboratory, Intel Corporation, San Francisco, CA 94111, USA
| | - Thomas A. Cleland
- Computational Physiology Laboratory, Dept. Psychology, Cornell University, Ithaca, NY 14853, USA
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11
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Oruro EM, Pardo GVE, Lucion AB, Calcagnotto ME, Idiart MAP. Maturation of pyramidal cells in anterior piriform cortex may be sufficient to explain the end of early olfactory learning in rats. ACTA ACUST UNITED AC 2019; 27:20-32. [PMID: 31843979 PMCID: PMC6919191 DOI: 10.1101/lm.050724.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
Studies have shown that neonate rodents exhibit high ability to learn a preference for novel odors associated with thermo-tactile stimuli that mimics maternal care. Artificial odors paired with vigorous strokes in rat pups younger than 10 postnatal days (P), but not older, rapidly induce an orientation-approximation behavior toward the conditioned odor in a two-choice preference test. The olfactory bulb (OB) and the anterior olfactory cortex (aPC), both modulated by norepinephrine (NE), have been identified as part of a neural circuit supporting this transitory olfactory learning. One possible explanation at the neuronal level for why the odor-stroke pairing induces consistent orientation-approximation behavior in <P10 pups, but not in >P10, is the coincident activation of prior existent neurons in the aPC mediating this behavior. Specifically, odor-stroke conditioning in <P10 pups may activate more mother/nest odor's responsive aPC neurons than in >P10 pups, promoting orientation-approximation behavior in the former but not in the latter. In order to test this hypothesis, we performed in vitro patch-clamp recordings of the aPC pyramidal neurons from rat pups from two age groups (P5–P8 and P14–P17) and built computational models for the OB-aPC neural circuit based on this physiological data. We conditioned the P5–P8 OB-aPC artificial circuit to an odor associated with NE activation (representing the process of maternal odor learning during mother–infant interactions inside the nest) and then evaluated the response of the OB-aPC circuit to the presentation of the conditioned odor. The results show that the number of responsive aPC neurons to the presentation of the conditioned odor in the P14–P17 OB-aPC circuit was lower than in the P5–P8 circuit, suggesting that at P14–P17, the reduced number of responsive neurons to the conditioned (maternal) odor might not be coincident with the responsive neurons for a second conditioned odor.
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Affiliation(s)
- Enver Miguel Oruro
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970 Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Grace V E Pardo
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil.,Centre for Interdisciplinary Science and Society Studies, Universidad de Ciencias y Humanidades, Los Olivos, Lima, 15314 Peru
| | - Aldo B Lucion
- Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Maria Elisa Calcagnotto
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Marco A P Idiart
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
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12
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Ross JM, Bendahmane M, Fletcher ML. Olfactory Bulb Muscarinic Acetylcholine Type 1 Receptors Are Required for Acquisition of Olfactory Fear Learning. Front Behav Neurosci 2019; 13:164. [PMID: 31379534 PMCID: PMC6659260 DOI: 10.3389/fnbeh.2019.00164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/08/2019] [Indexed: 11/13/2022] Open
Abstract
The olfactory bulb (OB) receives significant cholinergic innervation and widely expresses cholinergic receptors. While acetylcholine (ACh) is essential for olfactory learning, the exact mechanisms by which ACh modulates olfactory learning and whether it is specifically required in the OB remains unknown. Using behavioral pharmacology and optogenetics, we investigated the role of OB ACh in a simple olfactory fear learning paradigm. We find that antagonizing muscarinic ACh receptors (mAChRs) in the OB during fear conditioning but not testing significantly reduces freezing to the conditioned odor, without altering olfactory abilities. Additionally, we demonstrate that m1 mAChRs, rather than m2, are required for acquisition of olfactory fear. Finally, using mice expressing channelrhodopsin in cholinergic neurons, we show that stimulating ACh release specifically in the OB during odor-shock pairing can strengthen olfactory fear learning. Together these results define a role for ACh in olfactory associative learning and OB glomerular plasticity.
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Affiliation(s)
- Jordan M. Ross
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center (UTHSC), Memphis, TN, United States
| | - Mounir Bendahmane
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Max L. Fletcher
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center (UTHSC), Memphis, TN, United States
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14
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Ikeda K, Suzuki N, Bekkers JM. Sodium and potassium conductances in principal neurons of the mouse piriform cortex: a quantitative description. J Physiol 2018; 596:5397-5414. [PMID: 30194865 DOI: 10.1113/jp275824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 08/21/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The primary olfactory (or piriform) cortex is a promising model system for understanding how the cerebral cortex processes sensory information, although an investigation of the piriform cortex is hindered by a lack of detailed information about the intrinsic electrical properties of its component neurons. In the present study, we quantify the properties of voltage-dependent sodium currents and voltage- and calcium-dependent potassium currents in two important classes of excitatory neurons in the main input layer of the piriform cortex. We identify several classes of these currents and show that their properties are similar to those found in better-studied cortical regions. Our detailed quantitative descriptions of these currents will be valuable to computational neuroscientists who aim to build models that explain how the piriform cortex encodes odours. ABSTRACT The primary olfactory cortex (or piriform cortex, PC) is an anatomically simple palaeocortex that is increasingly used as a model system for investigating cortical sensory processing. However, little information is available on the intrinsic electrical conductances in neurons of the PC, hampering efforts to build realistic computational models of this cortex. In the present study, we used nucleated macropatches and whole-cell recordings to rigorously quantify the biophysical properties of voltage-gated sodium (NaV ), voltage-gated potassium (KV ) and calcium-activated potassium (KCa ) conductances in two major classes of glutamatergic neurons in layer 2 of the PC, semilunar (SL) cells and superficial pyramidal (SP) cells. We found that SL and SP cells both express a fast-inactivating NaV current, two types of KV current (A-type and delayed rectifier-type) and three types of KCa current (fast-, medium- and slow-afterhyperpolarization currents). The kinetic and voltage-dependent properties of the NaV and KV conductances were, with some exceptions, identical in SL and SP cells and similar to those found in neocortical pyramidal neurons. The KCa conductances were also similar across the different types of neurons. Our results are summarized in a series of empirical equations that should prove useful to computational neuroscientists seeking to model the PC. More broadly, our findings indicate that, at the level of single-cell electrical properties, this palaeocortex is not so different from the neocortex, vindicating efforts to use the PC as a model of cortical sensory processing in general.
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Affiliation(s)
- Kaori Ikeda
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | | | - John M Bekkers
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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15
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Osinski BL, Kim A, Xiao W, Mehta NM, Kay LM. Pharmacological manipulation of the olfactory bulb modulates beta oscillations: testing model predictions. J Neurophysiol 2018; 120:1090-1106. [PMID: 29847235 DOI: 10.1152/jn.00090.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian olfactory bulb (OB) generates gamma (40-100 Hz) and beta (15-30 Hz) local field potential (LFP) oscillations. Gamma oscillations arise at the peak of inhalation supported by dendrodendritic interactions between glutamatergic mitral cells (MCs) and GABAergic granule cells (GCs). Beta oscillations are induced by odorants in learning or odor sensitization paradigms, but their mechanism and function are still poorly understood. When centrifugal OB inputs are blocked, beta oscillations disappear, but gamma oscillations persist. Centrifugal inputs target primarily GABAergic interneurons in the GC layer (GCL) and regulate GC excitability, suggesting a causal link between beta oscillations and GC excitability. Our previous modeling work predicted that convergence of excitatory/inhibitory inputs onto MCs and centrifugal inputs onto GCs increase GC excitability sufficiently to produce beta oscillations primarily through voltage dependent calcium channel-mediated GABA release, independently of NMDA channels. We test some of the predictions of this model by examining the influence of NMDA and muscarinic acetylcholine (ACh) receptors, which affect GC excitability in different ways, on beta oscillations. A few minutes after intrabulbar infusion, scopolamine (muscarinic antagonist) suppressed odor-evoked beta in response to a strong stimulus but increased beta power in response to a weak stimulus, as predicted by our model. Pyriform cortex (PC) beta power was unchanged. Oxotremorine (muscarinic agonist) suppressed all oscillations, likely from overinhibition. APV, an NMDA receptor antagonist, suppressed gamma oscillations selectively (in OB and PC), lending support to the model's prediction that beta oscillations can be supported independently of NMDA receptors. NEW & NOTEWORTHY Olfactory bulb local field potential beta oscillations appear to be gated by GABAergic granule cell excitability. Reducing excitability with scopolamine reduces beta induced by strong odors but increases beta induced by weak odors. Beta oscillations rely on the same synapse as gamma oscillations but, unlike gamma, can persist in the absence of NMDA receptor activation. Pyriform cortex beta oscillations maintain power when olfactory bulb beta power is low, and the system maintains beta band coherence.
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Affiliation(s)
- Bolesław L Osinski
- Graduate Program in Biophysical Sciences, The University of Chicago , Chicago, Illinois.,Institute for Mind and Biology, The University of Chicago , Chicago, Illinois
| | - Alex Kim
- The College, The University of Chicago , Chicago, Illinois
| | - Wenxi Xiao
- Masters Program in Computational Social Sciences, The University of Chicago , Chicago, Illinois
| | - Nisarg M Mehta
- Institute for Mind and Biology, The University of Chicago , Chicago, Illinois
| | - Leslie M Kay
- Institute for Mind and Biology, The University of Chicago , Chicago, Illinois.,Department of Psychology, The University of Chicago , Chicago, Illinois
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Ejsmond MJ, Provenza FD. Is doping of cognitive performance an anti-herbivore adaptation? Alkaloids inhibiting acetylcholinesterase as a case. Ecosphere 2018. [DOI: 10.1002/ecs2.2129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Maciej J. Ejsmond
- Institute of Environmental Sciences; Jagiellonian University; ul. Gronostajowa 7 Kraków 30-387 Poland
- Department of Arctic Biology; The University Centre in Svalbard; Longyearbyen N-9171 Norway
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Choy JM, Suzuki N, Shima Y, Budisantoso T, Nelson SB, Bekkers JM. Optogenetic Mapping of Intracortical Circuits Originating from Semilunar Cells in the Piriform Cortex. Cereb Cortex 2017; 27:589-601. [PMID: 26503263 PMCID: PMC5939214 DOI: 10.1093/cercor/bhv258] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Despite its comparatively simple trilaminar architecture, the primary olfactory (piriform) cortex of mammals is capable of performing sophisticated sensory processing, an ability that is thought to depend critically on its extensive associational (intracortical) excitatory circuits. Here, we used a novel transgenic mouse model and optogenetics to measure the connectivity of associational circuits that originate in semilunar (SL) cells in layer 2a of the anterior piriform cortex (aPC). We generated a mouse line (48L) in which channelrhodopsin-2 (ChR) could be selectively expressed in a subset of SL cells. Light-evoked excitatory postsynaptic currents (EPSCs) could be evoked in superficial pyramidal cells (17.4% of n = 86 neurons) and deep pyramidal cells (33.3%, n = 9) in the aPC, but never in ChR- SL cells (0%, n = 34). Thus, SL cells monosynaptically excite pyramidal cells, but not other SL cells. Light-evoked EPSCs were also selectively elicited in 3 classes of GABAergic interneurons in layer 3 of the aPC. Our results show that SL cells are specialized for providing feedforward excitation of specific classes of neurons in the aPC, confirming that SL cells comprise a functionally distinctive input layer.
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Affiliation(s)
- Julian M.C. Choy
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Norimitsu Suzuki
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Yasuyuki Shima
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02453, USA
| | - Timotheus Budisantoso
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
- Department of Physiological Sciences, Graduate University for Advanced Studies, Okazaki444-8787, Japan
- Current address: Department of Physiology, School of Medicine, Keio University, Shinjuku, Tokyo 160-8582, Japan
| | - Sacha B. Nelson
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02453, USA
| | - John M. Bekkers
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
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de Almeida L, Idiart M, Dean O, Devore S, Smith DM, Linster C. Internal Cholinergic Regulation of Learning and Recall in a Model of Olfactory Processing. Front Cell Neurosci 2016; 10:256. [PMID: 27877112 PMCID: PMC5099168 DOI: 10.3389/fncel.2016.00256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/18/2016] [Indexed: 12/02/2022] Open
Abstract
In the olfactory system, cholinergic modulation has been associated with contrast modulation and changes in receptive fields in the olfactory bulb, as well the learning of odor associations in olfactory cortex. Computational modeling and behavioral studies suggest that cholinergic modulation could improve sensory processing and learning while preventing pro-active interference when task demands are high. However, how sensory inputs and/or learning regulate incoming modulation has not yet been elucidated. We here use a computational model of the olfactory bulb, piriform cortex (PC) and horizontal limb of the diagonal band of Broca (HDB) to explore how olfactory learning could regulate cholinergic inputs to the system in a closed feedback loop. In our model, the novelty of an odor is reflected in firing rates and sparseness of cortical neurons in response to that odor and these firing rates can directly regulate learning in the system by modifying cholinergic inputs to the system. In the model, cholinergic neurons reduce their firing in response to familiar odors—reducing plasticity in the PC, but increase their firing in response to novel odor—increasing PC plasticity. Recordings from HDB neurons in awake behaving rats reflect predictions from the model by showing that a subset of neurons decrease their firing as an odor becomes familiar.
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Affiliation(s)
- Licurgo de Almeida
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Marco Idiart
- Physics Institute Federal University of Rio Grande do Sul (UFRGS) Porto Alegre, Brazil
| | - Owen Dean
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Sasha Devore
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - David M Smith
- Department of Psychology, Cornell University Ithaca, NY, USA
| | - Christiane Linster
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
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19
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Neuromodulation of olfactory transformations. Curr Opin Neurobiol 2016; 40:170-177. [PMID: 27564660 DOI: 10.1016/j.conb.2016.07.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 12/26/2022]
Abstract
The olfactory bulb and piriform cortex are the best studied structures of the mammalian olfactory system and are heavily innervated by extrinsic neuromodulatory inputs. The state-dependent release of acetylcholine, norepinephrine, serotonin, and other neuromodulators into these olfactory structures alters a constellation of physiological parameters in neurons and synapses that together modify the computations performed on sensory signals. These modifications affect the specificity, detectability, discriminability, and other properties of odor representations and thereby govern perceptual performance. Whereas different neuromodulators have distinct cellular effects, and tend to be associated with nominally different functions, it also is clear that these purported functions overlap substantially, and that ad hoc hypotheses regarding the roles of particular neuromodulators may have reached the limits of their usefulness.
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20
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DelGaudio JM, Panella NJ. Presbynasalis. Int Forum Allergy Rhinol 2016; 6:1083-1087. [DOI: 10.1002/alr.21787] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/10/2016] [Accepted: 03/15/2016] [Indexed: 11/07/2022]
Affiliation(s)
- John M. DelGaudio
- Division of Rhinology and Sinus Surgery; Emory University; Atlanta GA
- Department of Otolaryngology-Head and Neck Surgery; Emory University; Atlanta GA
| | - Nicholas J. Panella
- Department of Otolaryngology-Head and Neck Surgery; Emory University; Atlanta GA
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21
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Osinski BL, Kay LM. Granule cell excitability regulates gamma and beta oscillations in a model of the olfactory bulb dendrodendritic microcircuit. J Neurophysiol 2016; 116:522-39. [PMID: 27121582 DOI: 10.1152/jn.00988.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/25/2016] [Indexed: 01/03/2023] Open
Abstract
Odors evoke gamma (40-100 Hz) and beta (20-30 Hz) oscillations in the local field potential (LFP) of the mammalian olfactory bulb (OB). Gamma (and possibly beta) oscillations arise from interactions in the dendrodendritic microcircuit between excitatory mitral cells (MCs) and inhibitory granule cells (GCs). When cortical descending inputs to the OB are blocked, beta oscillations are extinguished whereas gamma oscillations become larger. Much of this centrifugal input targets inhibitory interneurons in the GC layer and regulates the excitability of GCs, which suggests a causal link between the emergence of beta oscillations and GC excitability. We investigate the effect that GC excitability has on network oscillations in a computational model of the MC-GC dendrodendritic network with Ca(2+)-dependent graded inhibition. Results from our model suggest that when GC excitability is low, the graded inhibitory current mediated by NMDA channels and voltage-dependent Ca(2+) channels (VDCCs) is also low, allowing MC populations to fire in the gamma frequency range. When GC excitability is increased, the activation of NMDA receptors and other VDCCs is also increased, allowing the slow decay time constants of these channels to sustain beta-frequency oscillations. Our model argues that Ca(2+) flow through VDCCs alone could sustain beta oscillations and that the switch between gamma and beta oscillations can be triggered by an increase in the excitability state of a subpopulation of GCs.
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Affiliation(s)
- Bolesław L Osinski
- Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, Illinois; Institute for Mind and Biology, The University of Chicago, Chicago, Illinois; and
| | - Leslie M Kay
- Institute for Mind and Biology, The University of Chicago, Chicago, Illinois; and Department of Psychology, The University of Chicago, Chicago, Illinois
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22
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Effects of experimentally necessary changes in husbandry on olfactory memory: Chronic food restriction and social isolation. Physiol Behav 2016; 155:38-45. [DOI: 10.1016/j.physbeh.2015.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/16/2015] [Accepted: 12/02/2015] [Indexed: 01/25/2023]
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23
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Devore S, Pender-Morris N, Dean O, Smith D, Linster C. Basal forebrain dynamics during nonassociative and associative olfactory learning. J Neurophysiol 2015; 115:423-33. [PMID: 26561601 DOI: 10.1152/jn.00572.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 11/10/2015] [Indexed: 12/28/2022] Open
Abstract
Cholinergic and GABAergic projections from the horizontal diagonal band (HDB) and medial preoptic area (MCPO) of the basal forebrain to the olfactory system are associated with odor discrimination and odor learning, as well as modulation of neural responses in olfactory structures. Whereas pharmacological and lesion studies give insights into the functional role of these modulatory inputs on a slow timescale, the response dynamics of neurons in the HDB/MCPO during olfactory behaviors have not been investigated. In this study we examined how these neurons respond during two olfactory behaviors: spontaneous investigation of odorants and odor-reward association learning. We observe rich heterogeneity in the response dynamics of individual HDB/MCPO neurons, with a substantial fraction of neurons exhibiting task-related modulation. HDB/MCPO neurons show both rapid and transient responses during bouts of odor investigation and slow, long-lasting modulation of overall response rate based on behavioral demands. Specifically, baseline rates were higher during the acquisition phase of an odor-reward association than during spontaneous investigation or the recall phase of an odor reward association. Our results suggest that modulatory projections from the HDB/MCPO are poised to influence olfactory processing on multiple timescales, from hundreds of milliseconds to minutes, and are therefore capable of rapidly setting olfactory network dynamics during odor processing and learning.
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Affiliation(s)
- Sasha Devore
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York; and
| | | | - Owen Dean
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York; and
| | - David Smith
- Department of Psychology, Cornell University, Ithaca, New York
| | - Christiane Linster
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York; and
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24
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Li G, Linster C, Cleland TA. Functional differentiation of cholinergic and noradrenergic modulation in a biophysical model of olfactory bulb granule cells. J Neurophysiol 2015; 114:3177-200. [PMID: 26334007 DOI: 10.1152/jn.00324.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/01/2015] [Indexed: 01/19/2023] Open
Abstract
Olfactory bulb granule cells are modulated by both acetylcholine (ACh) and norepinephrine (NE), but the effects of these neuromodulators have not been clearly distinguished. We used detailed biophysical simulations of granule cells, both alone and embedded in a microcircuit with mitral cells, to measure and distinguish the effects of ACh and NE on cellular and microcircuit function. Cholinergic and noradrenergic modulatory effects on granule cells were based on data obtained from slice experiments; specifically, ACh reduced the conductance densities of the potassium M current and the calcium-dependent potassium current, whereas NE nonmonotonically regulated the conductance density of an ohmic potassium current. We report that the effects of ACh and NE on granule cell physiology are distinct and functionally complementary to one another. ACh strongly regulates granule cell firing rates and afterpotentials, whereas NE bidirectionally regulates subthreshold membrane potentials. When combined, NE can regulate the ACh-induced expression of afterdepolarizing potentials and persistent firing. In a microcircuit simulation developed to investigate the effects of granule cell neuromodulation on mitral cell firing properties, ACh increased spike synchronization among mitral cells, whereas NE modulated the signal-to-noise ratio. Coapplication of ACh and NE both functionally improved the signal-to-noise ratio and enhanced spike synchronization among mitral cells. In summary, our computational results support distinct and complementary roles for ACh and NE in modulating olfactory bulb circuitry and suggest that NE may play a role in the regulation of cholinergic function.
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Affiliation(s)
- Guoshi Li
- Department of Psychology, Cornell University, Ithaca, New York;
| | - Christiane Linster
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York
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25
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de Almeida L, Reiner SJ, Ennis M, Linster C. Computational modeling suggests distinct, location-specific function of norepinephrine in olfactory bulb and piriform cortex. Front Comput Neurosci 2015; 9:73. [PMID: 26136678 PMCID: PMC4468384 DOI: 10.3389/fncom.2015.00073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 05/27/2015] [Indexed: 12/02/2022] Open
Abstract
Noradrenergic modulation from the locus coerulus is often associated with the regulation of sensory signal-to-noise ratio. In the olfactory system, noradrenergic modulation affects both bulbar and cortical processing, and has been shown to modulate the detection of low concentration stimuli. We here implemented a computational model of the olfactory bulb and piriform cortex, based on known experimental results, to explore how noradrenergic modulation in the olfactory bulb and piriform cortex interact to regulate odor processing. We show that as predicted by behavioral experiments in our lab, norepinephrine can play a critical role in modulating the detection and associative learning of very low odor concentrations. Our simulations show that bulbar norepinephrine serves to pre-process odor representations to facilitate cortical learning, but not recall. We observe the typical non-uniform dose—response functions described for norepinephrine modulation and show that these are imposed mainly by bulbar, but not cortical processing.
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Affiliation(s)
- Licurgo de Almeida
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Seungdo J Reiner
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Matthew Ennis
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Christiane Linster
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
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26
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Gilra A, Bhalla US. Bulbar microcircuit model predicts connectivity and roles of interneurons in odor coding. PLoS One 2015; 10:e0098045. [PMID: 25942312 PMCID: PMC4420273 DOI: 10.1371/journal.pone.0098045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 04/23/2014] [Indexed: 01/13/2023] Open
Abstract
Stimulus encoding by primary sensory brain areas provides a data-rich context for understanding their circuit mechanisms. The vertebrate olfactory bulb is an input area having unusual two-layer dendro-dendritic connections whose roles in odor coding are unclear. To clarify these roles, we built a detailed compartmental model of the rat olfactory bulb that synthesizes a much wider range of experimental observations on bulbar physiology and response dynamics than has hitherto been modeled. We predict that superficial-layer inhibitory interneurons (periglomerular cells) linearize the input-output transformation of the principal neurons (mitral cells), unlike previous models of contrast enhancement. The linearization is required to replicate observed linear summation of mitral odor responses. Further, in our model, action-potentials back-propagate along lateral dendrites of mitral cells and activate deep-layer inhibitory interneurons (granule cells). Using this, we propose sparse, long-range inhibition between mitral cells, mediated by granule cells, to explain how the respiratory phases of odor responses of sister mitral cells can be sometimes decorrelated as observed, despite receiving similar receptor input. We also rule out some alternative mechanisms. In our mechanism, we predict that a few distant mitral cells receiving input from different receptors, inhibit sister mitral cells differentially, by activating disjoint subsets of granule cells. This differential inhibition is strong enough to decorrelate their firing rate phases, and not merely modulate their spike timing. Thus our well-constrained model suggests novel computational roles for the two most numerous classes of interneurons in the bulb.
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Affiliation(s)
- Aditya Gilra
- National Centre for Biological Sciences (NCBS), Tata Institute of Fundamental Research (TIFR), Bangalore, 560065, India
| | - Upinder S. Bhalla
- National Centre for Biological Sciences (NCBS), Tata Institute of Fundamental Research (TIFR), Bangalore, 560065, India
- * E-mail:
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27
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Distinct roles of bulbar muscarinic and nicotinic receptors in olfactory discrimination learning. J Neurosci 2014; 34:11244-60. [PMID: 25143606 DOI: 10.1523/jneurosci.1499-14.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The olfactory bulb (OB) and piriform cortex receive dense cholinergic projections from the basal forebrain. Cholinergic modulation within the piriform cortex has long been proposed to serve important functions in olfactory learning and memory. We here investigate how olfactory discrimination learning is regulated by cholinergic modulation of the OB inputs to the piriform cortex. We examined rats' performance on a two-alternative choice odor discrimination task following local, bilateral blockade of cholinergic nicotinic and/or muscarinic receptors in the OB. Results demonstrate that acquisition, but not recall, of novel discrimination problems is impaired following blockade of OB cholinergic receptors, although the relative contribution of muscarinic and nicotinic receptors depends on task difficulty. Blocking muscarinic receptors impairs learning for nearly all odor sets, whereas blocking nicotinic receptors only affects performance for perceptually similar odors. This pattern of behavioral effects is consistent with predictions from a model of cholinergic modulation in the OB and piriform cortex (de Almeida et al., 2013). Model simulations suggest that muscarinic and nicotinic receptors may serve complementary roles in regulating coherence and sparseness of the OB network output, which in turn differentially regulate the strength and overlap in cortical odor representations. Overall, our results suggest that muscarinic receptor blockade results in a bona fide learning impairment that may arise because cortical neurons are activated less often. Behavioral impairment following nicotinic receptor blockade may not be due to the inability of the cortex to learn, but rather arises because the cortex is unable to resolve highly overlapping input patterns.
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28
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Vaughan DN, Jackson GD. The piriform cortex and human focal epilepsy. Front Neurol 2014; 5:259. [PMID: 25538678 PMCID: PMC4259123 DOI: 10.3389/fneur.2014.00259] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 11/22/2014] [Indexed: 11/28/2022] Open
Abstract
It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic – being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability.
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Affiliation(s)
- David N Vaughan
- Florey Institute of Neuroscience and Mental Health , Heidelberg, VIC , Australia ; Department of Neurology, Austin Health , Heidelberg, VIC , Australia
| | - Graeme D Jackson
- Florey Institute of Neuroscience and Mental Health , Heidelberg, VIC , Australia ; Department of Neurology, Austin Health , Heidelberg, VIC , Australia ; Department of Medicine, University of Melbourne , Melbourne, VIC , Australia
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D'Souza RD, Vijayaraghavan S. Paying attention to smell: cholinergic signaling in the olfactory bulb. Front Synaptic Neurosci 2014; 6:21. [PMID: 25309421 PMCID: PMC4174753 DOI: 10.3389/fnsyn.2014.00021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/05/2014] [Indexed: 11/13/2022] Open
Abstract
The tractable, layered architecture of the olfactory bulb (OB), and its function as a relay between odor input and higher cortical processing, makes it an attractive model to study how sensory information is processed at a synaptic and circuit level. The OB is also the recipient of strong neuromodulatory inputs, chief among them being the central cholinergic system. Cholinergic axons from the basal forebrain modulate the activity of various cells and synapses within the OB, particularly the numerous dendrodendritic synapses, resulting in highly variable responses of OB neurons to odor input that is dependent upon the behavioral state of the animal. Behavioral, electrophysiological, anatomical, and computational studies examining the function of muscarinic and nicotinic cholinergic receptors expressed in the OB have provided valuable insights into the role of acetylcholine (ACh) in regulating its function. We here review various studies examining the modulation of OB function by cholinergic fibers and their target receptors, and provide putative models describing the role that cholinergic receptor activation might play in the encoding of odor information.
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Affiliation(s)
- Rinaldo D D'Souza
- Department of Physiology and Biophysics and the Neuroscience Program, School of Medicine, University of Colorado Aurora, CO, USA
| | - Sukumar Vijayaraghavan
- Department of Physiology and Biophysics and the Neuroscience Program, School of Medicine, University of Colorado Aurora, CO, USA
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30
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Schofield PW, Finnie S, Yong YM. The Role of Olfactory Challenge Tests in Incipient Dementia and Clinical Trial Design. Curr Neurol Neurosci Rep 2014; 14:479. [DOI: 10.1007/s11910-014-0479-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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31
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Tong MT, Peace ST, Cleland TA. Properties and mechanisms of olfactory learning and memory. Front Behav Neurosci 2014; 8:238. [PMID: 25071492 PMCID: PMC4083347 DOI: 10.3389/fnbeh.2014.00238] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/16/2014] [Indexed: 02/05/2023] Open
Abstract
Memories are dynamic physical phenomena with psychometric forms as well as characteristic timescales. Most of our understanding of the cellular mechanisms underlying the neurophysiology of memory, however, derives from one-trial learning paradigms that, while powerful, do not fully embody the gradual, representational, and statistical aspects of cumulative learning. The early olfactory system—particularly olfactory bulb—comprises a reasonably well-understood and experimentally accessible neuronal network with intrinsic plasticity that underlies both one-trial (adult aversive, neonatal) and cumulative (adult appetitive) odor learning. These olfactory circuits employ many of the same molecular and structural mechanisms of memory as, for example, hippocampal circuits following inhibitory avoidance conditioning, but the temporal sequences of post-conditioning molecular events are likely to differ owing to the need to incorporate new information from ongoing learning events into the evolving memory trace. Moreover, the shapes of acquired odor representations, and their gradual transformation over the course of cumulative learning, also can be directly measured, adding an additional representational dimension to the traditional metrics of memory strength and persistence. In this review, we describe some established molecular and structural mechanisms of memory with a focus on the timecourses of post-conditioning molecular processes. We describe the properties of odor learning intrinsic to the olfactory bulb and review the utility of the olfactory system of adult rodents as a memory system in which to study the cellular mechanisms of cumulative learning.
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Affiliation(s)
- Michelle T Tong
- Computational Physiology Lab, Department of Psychology, Cornell University Ithaca, NY, USA
| | - Shane T Peace
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Thomas A Cleland
- Computational Physiology Lab, Department of Psychology, Cornell University Ithaca, NY, USA
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Linster C, Fontanini A. Functional neuromodulation of chemosensation in vertebrates. Curr Opin Neurobiol 2014; 29:82-7. [PMID: 24971592 DOI: 10.1016/j.conb.2014.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
Abstract
Neuromodulation can be defined as a biophysical process that serves to modify-or modulate-the computation performed by a neuron or network as a function of task demands and behavioral state of the animal. These modulatory effects often involve substances extrinsic to the network under observation, such as acetylcholine (ACh), norepinephrine (NE), histamine, serotonin (5-HT), dopamine (DA), and a variety of neuropeptides. Olfactory and gustatory processes especially need to be adaptive and respond flexibly to changing environments, availability of resources and physiological needs. It is therefore crucial to understand the neuromodulatory processes that regulate the function of these systems.
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Affiliation(s)
- Christiane Linster
- Computational Physiology Lab, Department of Neurobiology and Behavior, Mudd Hall W249, Cornell University, Ithaca, NY 14853, USA.
| | - Alfredo Fontanini
- Dept. of Neurobiology and Behavior, Graduate Program in Neuroscience, State University of New York at Stony Brook, Stony Brook, NY 11794, USA.
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Cholinergic inputs from Basal forebrain add an excitatory bias to odor coding in the olfactory bulb. J Neurosci 2014; 34:4654-64. [PMID: 24672011 DOI: 10.1523/jneurosci.5026-13.2014] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cholinergic modulation of central circuits is associated with active sensation, attention, and learning, yet the neural circuits and temporal dynamics underlying cholinergic effects on sensory processing remain unclear. Understanding the effects of cholinergic modulation on particular circuits is complicated by the widespread projections of cholinergic neurons to telencephalic structures that themselves are highly interconnected. Here we examined how cholinergic projections from basal forebrain to the olfactory bulb (OB) modulate output from the first stage of sensory processing in the mouse olfactory system. By optogenetically activating their axons directly in the OB, we found that cholinergic projections from basal forebrain regulate OB output by increasing the spike output of presumptive mitral/tufted cells. Cholinergic stimulation increased mitral/tufted cell spiking in the absence of inhalation-driven sensory input and further increased spiking responses to inhalation of odorless air and to odorants. This modulation was rapid and transient, was dependent on local cholinergic signaling in the OB, and differed from modulation by optogenetic activation of cholinergic neurons in basal forebrain, which led to a mixture of mitral/tufted cell excitation and suppression. Finally, bulbar cholinergic enhancement of mitral/tufted cell odorant responses was robust and occurred independent of the strength or even polarity of the odorant-evoked response, indicating that cholinergic modulation adds an excitatory bias to mitral/tufted cells as opposed to increasing response gain or sharpening response spectra. These results are consistent with a role for the basal forebrain cholinergic system in dynamically regulating the sensitivity to or salience of odors during active sensing of the olfactory environment.
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Kaplan BA, Lansner A. A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system. Front Neural Circuits 2014; 8:5. [PMID: 24570657 PMCID: PMC3916767 DOI: 10.3389/fncir.2014.00005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/09/2014] [Indexed: 01/01/2023] Open
Abstract
Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin-Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian-Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian-Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures.
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Affiliation(s)
- Bernhard A Kaplan
- Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology Stockholm, Sweden ; Stockholm Brain Institute, Karolinska Institute Stockholm, Sweden
| | - Anders Lansner
- Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology Stockholm, Sweden ; Stockholm Brain Institute, Karolinska Institute Stockholm, Sweden ; Department of Numerical Analysis and Computer Science, Stockholm University Stockholm, Sweden
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Doty RL, Kamath V. The influences of age on olfaction: a review. Front Psychol 2014; 5:20. [PMID: 24570664 PMCID: PMC3916729 DOI: 10.3389/fpsyg.2014.00020] [Citation(s) in RCA: 346] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/08/2014] [Indexed: 12/21/2022] Open
Abstract
Decreased olfactory function is very common in the older population, being present in over half of those between the ages of 65 and 80 years and in over three quarters of those over the age of 80 years. Such dysfunction significantly influences physical well-being and quality of life, nutrition, the enjoyment of food, as well as everyday safety. Indeed a disproportionate number of the elderly die in accident gas poisonings each year. As described in this review, multiple factors contribute to such age-related loss, including altered nasal engorgement, increased propensity for nasal disease, cumulative damage to the olfactory epithelium from viral and other environmental insults, decrements in mucosal metabolizing enzymes, ossification of cribriform plate foramina, loss of selectivity of receptor cells to odorants, changes in neurotransmitter and neuromodulator systems, and neuronal expression of aberrant proteins associated with neurodegenerative disease. It is now well established that decreased smell loss can be an early sign of such neurodegenerative diseases as Alzheimer's disease and sporadic Parkinson's disease. In this review we provide an overview of the anatomy and physiology of the aging olfactory system, how this system is clinically evaluated, and the multiple pathophysiological factors that are associated with its dysfunction.
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Affiliation(s)
- Richard L. Doty
- Department of Otorhinolaryngology: Head and Neck Surgery, Smell and Taste Center, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
| | - Vidyulata Kamath
- Department of Otorhinolaryngology: Head and Neck Surgery, Smell and Taste Center, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
- Division of Medical Psychology, Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of MedicineBaltimore, MD, USA
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Cleland TA. Construction of Odor Representations by Olfactory Bulb Microcircuits. PROGRESS IN BRAIN RESEARCH 2014; 208:177-203. [DOI: 10.1016/b978-0-444-63350-7.00007-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Neurons and circuits for odor processing in the piriform cortex. Trends Neurosci 2013; 36:429-38. [PMID: 23648377 DOI: 10.1016/j.tins.2013.04.005] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/04/2013] [Accepted: 04/04/2013] [Indexed: 01/13/2023]
Abstract
Increased understanding of the early stages of olfaction has lead to a renewed interest in the higher brain regions responsible for forming unified 'odor images' from the chemical components detected by the nose. The piriform cortex, which is one of the first cortical destinations of olfactory information in mammals, is a primitive paleocortex that is critical for the synthetic perception of odors. Here we review recent work that examines the cellular neurophysiology of the piriform cortex. Exciting new findings have revealed how the neurons and circuits of the piriform cortex process odor information, demonstrating that, despite its superficial simplicity, the piriform cortex is a remarkably subtle and intricate neural circuit.
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Morrison GL, Fontaine CJ, Harley CW, Yuan Q. A role for the anterior piriform cortex in early odor preference learning: evidence for multiple olfactory learning structures in the rat pup. J Neurophysiol 2013; 110:141-52. [PMID: 23576704 DOI: 10.1152/jn.00072.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
cFos activation in the anterior piriform cortex (aPC) occurs in early odor preference learning in rat pups (Roth and Sullivan 2005). Here we provide evidence that the pairing of odor as a conditioned stimulus and β-adrenergic activation in the aPC as an unconditioned stimulus generates early odor preference learning. β-Adrenergic blockade in the aPC prevents normal preference learning. Enhancement of aPC cAMP response element-binding protein (CREB) phosphorylation in trained hemispheres is consistent with a role for this cascade in early odor preference learning in the aPC. In vitro experiments suggested theta-burst-mediated long-term potentiation (LTP) at the lateral olfactory tract (LOT) to aPC synapse depends on N-methyl-D-aspartate (NMDA) receptors and can be significantly enhanced by β-adrenoceptor activation, which causes increased glutamate release from LOT synapses during LTP induction. NMDA receptors in aPC are also shown to be critical for the acquisition, but not expression, of odor preference learning, as would be predicted if they mediate initial β-adrenoceptor-promoted aPC plasticity. Ex vivo experiments 3 and 24 h after odor preference training reveal an enhanced LOT-aPC field excitatory postsynaptic potential (EPSP). At 3 h both presynaptic and postsynaptic potentiations support EPSP enhancement while at 24 h only postsynaptic potentiation is seen. LOT-LTP in aPC is excluded by odor preference training. Taken together with earlier work on the role of the olfactory bulb in early odor preference learning, these outcomes suggest early odor preference learning is normally supported by and requires multiple plastic changes at least at two levels of olfactory circuitry.
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Affiliation(s)
- Gillian L Morrison
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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