1
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Howe JR, Chan CL, Lee D, Blanquart M, Romero HK, Zadina AN, Lemieux ME, Mills F, Desplats PA, Tye KM, Root CM. Control of innate olfactory valence by segregated cortical amygdala circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.26.600895. [PMID: 38979308 PMCID: PMC11230396 DOI: 10.1101/2024.06.26.600895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Animals perform innate behaviors that are stereotyped responses to specific evolutionarily relevant stimuli in the absence of prior learning or experience. These behaviors can be reduced to an axis of valence, whereby specific odors evoke approach or avoidance. The cortical amygdala (plCoA) mediates innate attraction and aversion to odor. However, little is known about how this brain area gives rise to behaviors of opposing motivational valence. Here, we sought to define the circuit features of plCoA that give rise to innate olfactory behaviors of valence. We characterized the physiology, gene expression, and projections of this structure, identifying a divergent, topographic organization that selectively controls innate attraction and avoidance to odor. First, we examined odor-evoked responses in these areas and found sparse encoding of odor identity, but not valence. We next considered a topographic organization and found that optogenetic stimulation of the anterior and posterior domains of plCoA elicits attraction and avoidance, respectively, suggesting a functional axis for valence. Using single cell and spatial RNA sequencing, we identified the molecular cell types in plCoA, revealing an anteroposterior gradient in cell types, whereby anterior glutamatergic neurons preferentially express Slc17a6 and posterior neurons express Slc17a7. Activation of these respective cell types recapitulates appetitive and aversive valence behaviors, and chemogenetic inhibition reveals partial necessity for valence responses to innate appetitive or aversive odors. Finally, we identified topographically organized circuits defined by projections, whereby anterior neurons preferentially project to medial amygdala, and posterior neurons preferentially project to nucleus accumbens, which are respectively sufficient and necessary for innate negative and positive olfactory valence. Together, these data advance our understanding of how the olfactory system generates stereotypic, hardwired attraction and avoidance, and supports a model whereby distinct, topographically distributed plCoA populations direct innate olfactory valence responses by signaling to divergent valence-specific targets, linking upstream olfactory identity to downstream valence behaviors, through a population code. This represents a novel circuit motif in which valence encoding is represented not by the firing properties of individual neurons, but by population level identity encoding that is routed through divergent targets to mediate distinct valence.
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Affiliation(s)
- James R Howe
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
- These authors contributed equally
| | - Chung-Lung Chan
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
- These authors contributed equally
| | - Donghyung Lee
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Marlon Blanquart
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | - Haylie K Romero
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Abigail N Zadina
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, 10027, USA
| | | | - Fergil Mills
- Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | - Paula A Desplats
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kay M Tye
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
- Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, La Jolla, CA 92037, USA
| | - Cory M Root
- Department of Biological Sciences, Section of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
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2
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Fulton KA, Zimmerman D, Samuel A, Vogt K, Datta SR. Common principles for odour coding across vertebrates and invertebrates. Nat Rev Neurosci 2024; 25:453-472. [PMID: 38806946 DOI: 10.1038/s41583-024-00822-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 05/30/2024]
Abstract
The olfactory system is an ideal and tractable system for exploring how the brain transforms sensory inputs into behaviour. The basic tasks of any olfactory system include odour detection, discrimination and categorization. The challenge for the olfactory system is to transform the high-dimensional space of olfactory stimuli into the much smaller space of perceived objects and valence that endows odours with meaning. Our current understanding of how neural circuits address this challenge has come primarily from observations of the mechanisms of the brain for processing other sensory modalities, such as vision and hearing, in which optimized deep hierarchical circuits are used to extract sensory features that vary along continuous physical dimensions. The olfactory system, by contrast, contends with an ill-defined, high-dimensional stimulus space and discrete stimuli using a circuit architecture that is shallow and parallelized. Here, we present recent observations in vertebrate and invertebrate systems that relate the statistical structure and state-dependent modulation of olfactory codes to mechanisms of perception and odour-guided behaviour.
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Affiliation(s)
- Kara A Fulton
- Department of Neuroscience, Harvard Medical School, Boston, MA, USA
| | - David Zimmerman
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Aravi Samuel
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Katrin Vogt
- Department of Physics, Harvard University, Cambridge, MA, USA.
- Department of Biology, University of Konstanz, Konstanz, Germany.
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.
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3
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Licht T, Yunerman M, Maor I, Lawabny N, Oz Rokach R, Shiff I, Mizrahi A, Rokni D. Adaptive olfactory circuitry restores function despite severe olfactory bulb degeneration. Curr Biol 2023; 33:4857-4868.e6. [PMID: 37858342 PMCID: PMC10681124 DOI: 10.1016/j.cub.2023.09.061] [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: 02/20/2023] [Revised: 08/31/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023]
Abstract
The olfactory bulb (OB) is a critical component of mammalian olfactory neuroanatomy. Beyond being the first and sole relay station for olfactory information to the rest of the brain, it also contains elaborate stereotypical circuitry that is considered essential for olfaction. Indeed, substantial lesions of the OB in rodents lead to anosmia. Here, we examined the circuitry that underlies olfaction in a mouse model with severe developmental degeneration of the OB. These mice could perform odor-guided tasks and even responded normally to innate olfactory cues. Despite the near total loss of the OB, piriform cortices in these mice responded to odors, and its neural activity sufficed to decode odor identity. We found that sensory neurons express the full repertoire of olfactory receptors, and their axons project primarily to the rudiments of the OB but also, ectopically, to olfactory cortical regions. Within the OB, the number of principal neurons was greatly reduced, and the morphology of their dendrites was abnormal, extending over large regions within the OB. Glomerular organization was totally lost in the severe cases of OB degeneration and altered in the more conserved OBs. This study shows that olfactory functionality can be preserved despite reduced and aberrant circuitry that is missing many of the elements believed to be essential for olfaction, and it may explain reported retention of olfaction in humans with degenerated OBs.
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Affiliation(s)
- Tamar Licht
- Department of Medical Neurobiology, Faculty of Medicine and IMRIC, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel.
| | - Michael Yunerman
- Department of Medical Neurobiology, Faculty of Medicine and IMRIC, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel
| | - Ido Maor
- Department of Neurobiology, The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, 9190401 Jerusalem, Israel
| | - Naheel Lawabny
- Department of Medical Neurobiology, Faculty of Medicine and IMRIC, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel
| | - Renana Oz Rokach
- Department of Medical Neurobiology, Faculty of Medicine and IMRIC, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel
| | - Idit Shiff
- Genomics Applications Laboratory, Core Research Facility, Faculty of Medicine, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel
| | - Adi Mizrahi
- Department of Neurobiology, The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, 9190401 Jerusalem, Israel
| | - Dan Rokni
- Department of Medical Neurobiology, Faculty of Medicine and IMRIC, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel.
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4
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Shaffer C, Barrett LF, Quigley KS. Signal processing in the vagus nerve: Hypotheses based on new genetic and anatomical evidence. Biol Psychol 2023; 182:108626. [PMID: 37419401 PMCID: PMC10563766 DOI: 10.1016/j.biopsycho.2023.108626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 06/25/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023]
Abstract
Each organism must regulate its internal state in a metabolically efficient way as it interacts in space and time with an ever-changing and only partly predictable world. Success in this endeavor is largely determined by the ongoing communication between brain and body, and the vagus nerve is a crucial structure in that dialogue. In this review, we introduce the novel hypothesis that the afferent vagus nerve is engaged in signal processing rather than just signal relay. New genetic and structural evidence of vagal afferent fiber anatomy motivates two hypotheses: (1) that sensory signals informing on the physiological state of the body compute both spatial and temporal viscerosensory features as they ascend the vagus nerve, following patterns found in other sensory architectures, such as the visual and olfactory systems; and (2) that ascending and descending signals modulate one another, calling into question the strict segregation of sensory and motor signals, respectively. Finally, we discuss several implications of our two hypotheses for understanding the role of viscerosensory signal processing in predictive energy regulation (i.e., allostasis) as well as the role of metabolic signals in memory and in disorders of prediction (e.g., mood disorders).
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Affiliation(s)
- Clare Shaffer
- Department of Psychology, College of Science, Northeastern University, Boston, MA, USA.
| | - Lisa Feldman Barrett
- Department of Psychology, College of Science, Northeastern University, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Karen S Quigley
- Department of Psychology, College of Science, Northeastern University, Boston, MA, USA.
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Pompeiano M, Colonnese MT. cFOS as a biomarker of activity maturation in the hippocampal formation. Front Neurosci 2023; 17:929461. [PMID: 37521697 PMCID: PMC10374841 DOI: 10.3389/fnins.2023.929461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/23/2023] [Indexed: 08/01/2023] Open
Abstract
We explored the potential for cFOS expression as a marker of functional development of "resting-state" waking activity in the extended network of the hippocampus and entorhinal cortex. We examined sleeping and awake mice at (P)ostnatal days 5, 9, 13, and 17 as well as in adulthood. We find that cFOS expression is state-dependent even at 5 days old, with reliable staining occurring only in the awake mice. Even during waking, cFOS expression was rare and weak at P5. The septal nuclei, entorhinal cortex layer (L)2, and anterodorsal thalamus were exceptional in that they had robust cFOS expression at P5 that was similar to or greater than in adulthood. Significant P5 expression was also observed in the dentate gyrus, entorhinal cortex L6, postsubiculum L4-6, ventral subiculum, supramammillary nucleus, and posterior hypothalamic nucleus. The expression in these regions grew stronger with age, and the expression in new regions was added progressively at P9 and P13 by which point the overall expression pattern in many regions was qualitatively similar to the adult. Six regions-CA1, dorsal subiculum, postsubiculum L2-3, reuniens nucleus, and perirhinal and postrhinal cortices-were very late developing, mostly achieving adult levels only after P17. Our findings support a number of developmental principles. First, early spontaneous activity patterns induced by muscle twitches during sleep do not induce robust cFOS expression in the extended hippocampal network. Second, the development of cFOS expression follows the progressive activation along the trisynaptic circuit, rather than birth date or cellular maturation. Third, we reveal components of the egocentric head-direction and theta-rhythm circuits as the earliest cFOS active circuits in the forebrain. Our results suggest that cFOS staining may provide a reliable and sensitive biomarker for hippocampal formation activity development, particularly in regard to the attainment of a normal waking state and synchronizing rhythms such as theta and gamma.
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Affiliation(s)
- Maria Pompeiano
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, United States
- Departamento de Bioingeniería, Universidad Carlos III de Madrid, Madrid, Spain
| | - Matthew T. Colonnese
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, United States
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6
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Brunert D, Quintela RM, Rothermel M. The anterior olfactory nucleus revisited - an emerging role for neuropathological conditions? Prog Neurobiol 2023:102486. [PMID: 37343762 DOI: 10.1016/j.pneurobio.2023.102486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
Olfaction is an important sensory modality for many species and greatly influences animal and human behavior. Still, much about olfactory perception remains unknown. The anterior olfactory nucleus is one of the brain's central early olfactory processing areas. Located directly posterior to the olfactory bulb in the olfactory peduncle with extensive in- and output connections and unique cellular composition, it connects olfactory processing centers of the left and right hemispheres. Almost 20 years have passed since the last comprehensive review on the anterior olfactory nucleus has been published and significant advances regarding its anatomy, function, and pathophysiology have been made in the meantime. Here we briefly summarize previous knowledge on the anterior olfactory nucleus, give detailed insights into the progress that has been made in recent years, and map out its emerging importance in translational research of neurological diseases.
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Affiliation(s)
- Daniela Brunert
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | | | - Markus Rothermel
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany.
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7
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Idris A, Christensen BA, Walker EM, Maier JX. Multisensory integration of orally-sourced gustatory and olfactory inputs to the posterior piriform cortex in awake rats. J Physiol 2023; 601:151-169. [PMID: 36385245 PMCID: PMC9869978 DOI: 10.1113/jp283873] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/09/2022] [Indexed: 11/18/2022] Open
Abstract
Flavour refers to the sensory experience of food, which is a combination of sensory inputs sourced from multiple modalities during consumption, including taste and odour. Previous work has demonstrated that orally-sourced taste and odour cues interact to determine perceptual judgements of flavour stimuli, although the underlying cellular- and circuit-level neural mechanisms remain unknown. We recently identified a region of the piriform olfactory cortex in rats that responds to both taste and odour stimuli. Here, we investigated how converging taste and odour inputs to this area interact to affect single neuron responsiveness ensemble coding of flavour identity. To accomplish this, we recorded spiking activity from ensembles of single neurons in the posterior piriform cortex (pPC) in awake, tasting rats while delivering taste solutions, odour solutions and taste + odour mixtures directly into the oral cavity. Our results show that taste and odour inputs evoke highly selective, temporally-overlapping responses in multisensory pPC neurons. Comparing responses to mixtures and their unisensory components revealed that taste and odour inputs interact in a non-linear manner to produce unique response patterns. Taste input enhances trial-by-trial decoding of odour identity from small ensembles of simultaneously recorded neurons. Together, these results demonstrate that taste and odour inputs to pPC interact in complex, non-linear ways to form amodal flavour representations that enhance identity coding. KEY POINTS: Experience of food involves taste and smell, although how information from these different senses is combined by the brain to create our sense of flavour remains unknown. We recorded from small groups of neurons in the olfactory cortex of awake rats while they consumed taste solutions, odour solutions and taste + odour mixtures. Taste and smell solutions evoke highly selective responses. When presented in a mixture, taste and smell inputs interacted to alter responses, resulting in activation of unique sets of neurons that could not be predicted by the component responses. Synergistic interactions increase discriminability of odour representations. The olfactory cortex uses taste and smell to create new information representing multisensory flavour identity.
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Affiliation(s)
- Ammar Idris
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Brooke A. Christensen
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Ellen M. Walker
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Joost X. Maier
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
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8
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Endo K, Kazama H. Central organization of a high-dimensional odor space. Curr Opin Neurobiol 2022; 73:102528. [DOI: 10.1016/j.conb.2022.102528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 11/03/2022]
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9
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Schreck MR, Zhuang L, Janke E, Moberly AH, Bhattarai JP, Gottfried JA, Wesson DW, Ma M. State-dependent olfactory processing in freely behaving mice. Cell Rep 2022; 38:110450. [PMID: 35235805 PMCID: PMC8958632 DOI: 10.1016/j.celrep.2022.110450] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 11/07/2021] [Accepted: 02/07/2022] [Indexed: 11/06/2022] Open
Abstract
Decreased responsiveness to sensory stimuli during sleep is presumably mediated via thalamic gating. Without an obligatory thalamic relay in the olfactory system, the anterior piriform cortex (APC) is suggested to be a gate in anesthetized states. However, olfactory processing in natural sleep states remains undetermined. Here, we simultaneously record local field potentials (LFPs) in hierarchical olfactory regions (olfactory bulb [OB], APC, and orbitofrontal cortex) while optogenetically activating olfactory sensory neurons, ensuring consistent peripheral inputs across states in behaving mice. Surprisingly, evoked LFPs in sleep states (both non-rapid eye movement [NREM] and rapid eye movement [REM]) are larger and contain greater gamma-band power and cross-region coherence (compared to wakefulness) throughout the olfactory pathway, suggesting the lack of a central gate. Single-unit recordings from the OB and APC reveal a higher percentage of responsive neurons during sleep with a higher incidence of suppressed firing. Additionally, nasal breathing is slower and shallower during sleep, suggesting a partial peripheral gating mechanism. Schreck et al. examine how the olfactory system responds to the same peripheral stimulus during natural sleep and wake in mice. Larger responses along the pathway during sleep suggest the lack of a central gate, but slower and shallower breathing may act as a partial peripheral gate to reduce olfactory input.
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Affiliation(s)
- Mary R Schreck
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Liujing Zhuang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Emma Janke
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Andrew H Moberly
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Janardhan P Bhattarai
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jay A Gottfried
- Department of Psychology, University of Pennsylvania, School of Arts and Sciences; Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Daniel W Wesson
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA
| | - Minghong Ma
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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10
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Hakim M, Beecher K, Jacques A, Chaaya N, Belmer A, Battle AR, Johnson LR, Bartlett SE, Chehrehasa F. Retrieval of olfactory fear memory alters cell proliferation and expression of pCREB and pMAPK in the corticomedial amygdala and piriform cortex. Chem Senses 2022; 47:6673813. [PMID: 35997758 PMCID: PMC9397123 DOI: 10.1093/chemse/bjac021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The brain forms robust associations between odors and emotionally salient memories, making odors especially effective at triggering fearful or traumatic memories. Using Pavlovian olfactory fear conditioning (OFC), a variant of the traditional tone-shock paradigm, this study explored the changes involved in its processing. We assessed the expression of neuronal plasticity markers phosphorylated cyclic adenosine monophosphate response element binding protein (pCREB) and phosphorylated mitogen-activated protein kinase (pMAPK) 24 h and 14 days following OFC, in newborn neurons (EdU+) and in brain regions associated with olfactory memory processing; the olfactory bulb, piriform cortex, amygdale, and hippocampus. Here, we show that all proliferating neurons in the dentate gyrus of the hippocampus and glomerular layer of the olfactory bulb were colocalized with pCREB at 24 h and 14 days post-conditioning, and the number of proliferating neurons at both time points were statistically similar. This suggests the occurrence of long-term potentiation within the neurons of this pathway. Finally, OFC significantly increased the density of pCREB- and pMAPK-positive immunoreactive neurons in the medial and cortical subnuclei of the amygdala and the posterior piriform cortex, suggesting their key involvement in its processing. Together, our investigation identifies changes in neuroplasticity within critical neural circuits responsible for olfactory fear memory.
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Affiliation(s)
- Marziah Hakim
- Addiction Neuroscience and Obesity Laboratory, School of Biomedical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Kate Beecher
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Angela Jacques
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Nicholas Chaaya
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Arnauld Belmer
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Andrew R Battle
- Addiction Neuroscience and Obesity Laboratory, School of Biomedical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Luke R Johnson
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia.,School of Medicine. Division of Psychology, University of Tasmania, Launceston, TAS, Australia
| | - Selena E Bartlett
- Addiction Neuroscience and Obesity Laboratory, School of Clinical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Fatemeh Chehrehasa
- Addiction Neuroscience and Obesity Laboratory, School of Biomedical Sciences, Faculty of Health, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
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11
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Ziegler-Waldkirch S, Friesen M, Loreth D, Sauer JF, Kemna S, Hilse A, Erny D, Helm C, d´Errico P, Prinz M, Bartos M, Meyer-Luehmann M. Seed-induced Aβ deposition alters neuronal function and impairs olfaction in a mouse model of Alzheimer's disease. Mol Psychiatry 2022; 27:4274-4284. [PMID: 35869271 PMCID: PMC9718674 DOI: 10.1038/s41380-022-01686-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) which ultimately forms plaques. These Aβ deposits can be induced in APP transgenic mouse models by prion-like seeding. It has been widely accepted that anosmia and hyposmia occur during the early stages of AD, even before cognitive deficits are present. In order to determine the impact of seed-induced Aβ deposits on olfaction, we performed intracerebral injections of seed-competent brain homogenate into the olfactory bulb of young pre-depositing APP transgenic mice. Remarkably, we observed a dramatic olfactory impairment in those mice. Furthermore, the number of newborn neurons as well as the activity of cells in the mitral cell layer was decreased. Notably, exposure to an enriched environment reduced Aβ seeding, vivified neurogenesis and most importantly reversed olfactory deficits. Based on our findings, we conclude that altered neuronal function as a result of induced Aβ pathology might contribute to olfactory dysfunction in AD.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marina Friesen
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Desirée Loreth
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.13648.380000 0001 2180 3484Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jonas-Frederic Sauer
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany
| | - Solveig Kemna
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Alexandra Hilse
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Daniel Erny
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Christina Helm
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Paolo d´Errico
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marco Prinz
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Marlene Bartos
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center - University of Freiburg, 79106, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, 79110, Freiburg, Germany. .,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110, Freiburg, Germany.
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12
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Poo C, Agarwal G, Bonacchi N, Mainen ZF. Spatial maps in piriform cortex during olfactory navigation. Nature 2021; 601:595-599. [PMID: 34937941 DOI: 10.1038/s41586-021-04242-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 11/12/2021] [Indexed: 11/10/2022]
Abstract
Odours are a fundamental part of the sensory environment used by animals to guide behaviours such as foraging and navigation1,2. Primary olfactory (piriform) cortex is thought to be the main cortical region for encoding odour identity3-8. Here, using neural ensemble recordings in freely moving rats performing an odour-cued spatial choice task, we show that posterior piriform cortex neurons carry a robust spatial representation of the environment. Piriform spatial representations have features of a learned cognitive map, being most prominent near odour ports, stable across behavioural contexts and independent of olfactory drive or reward availability. The accuracy of spatial information carried by individual piriform neurons was predicted by the strength of their functional coupling to the hippocampal theta rhythm. Ensembles of piriform neurons concurrently represented odour identity as well as spatial locations of animals, forming an odour-place map. Our results reveal a function for piriform cortex in spatial cognition and suggest that it is well-suited to form odour-place associations and guide olfactory-cued spatial navigation.
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Affiliation(s)
- Cindy Poo
- Champalimaud Foundation, Lisbon, Portugal.
| | - Gautam Agarwal
- W. M. Keck Science Center, The Claremont Colleges, Claremont, CA, USA
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13
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Samuelsen CL, Vincis R. Cortical Hub for Flavor Sensation in Rodents. Front Syst Neurosci 2021; 15:772286. [PMID: 34867223 PMCID: PMC8636119 DOI: 10.3389/fnsys.2021.772286] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 01/05/2023] Open
Abstract
The experience of eating is inherently multimodal, combining intraoral gustatory, olfactory, and somatosensory signals into a single percept called flavor. As foods and beverages enter the mouth, movements associated with chewing and swallowing activate somatosensory receptors in the oral cavity, dissolve tastants in the saliva to activate taste receptors, and release volatile odorant molecules to retronasally activate olfactory receptors in the nasal epithelium. Human studies indicate that sensory cortical areas are important for intraoral multimodal processing, yet their circuit-level mechanisms remain unclear. Animal models allow for detailed analyses of neural circuits due to the large number of molecular tools available for tracing and neuronal manipulations. In this review, we concentrate on the anatomical and neurophysiological evidence from rodent models toward a better understanding of the circuit-level mechanisms underlying the cortical processing of flavor. While more work is needed, the emerging view pertaining to the multimodal processing of food and beverages is that the piriform, gustatory, and somatosensory cortical regions do not function solely as independent areas. Rather they act as an intraoral cortical hub, simultaneously receiving and processing multimodal sensory information from the mouth to produce the rich and complex flavor experience that guides consummatory behavior.
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Affiliation(s)
- Chad L Samuelsen
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States
| | - Roberto Vincis
- Department of Biological Science and Program in Neuroscience, Florida State University, Tallahassee, FL, United States
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14
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Abstract
Olfaction is fundamentally distinct from other sensory modalities. Natural odor stimuli are complex mixtures of volatile chemicals that interact in the nose with a receptor array that, in rodents, is built from more than 1,000 unique receptors. These interactions dictate a peripheral olfactory code, which in the brain is transformed and reformatted as it is broadcast across a set of highly interconnected olfactory regions. Here we discuss the problems of characterizing peripheral population codes for olfactory stimuli, of inferring the specific functions of different higher olfactory areas given their extensive recurrence, and of ultimately understanding how odor representations are linked to perception and action. We argue that, despite the differences between olfaction and other sensory modalities, addressing these specific questions will reveal general principles underlying brain function.
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Affiliation(s)
- David H Brann
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Sandeep Robert Datta
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA;
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15
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Traub RD, Tu Y, Whittington MA. Cell assembly formation and structure in a piriform cortex model. Rev Neurosci 2021; 33:111-132. [PMID: 34271607 DOI: 10.1515/revneuro-2021-0056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 06/19/2021] [Indexed: 11/15/2022]
Abstract
The piriform cortex is rich in recurrent excitatory synaptic connections between pyramidal neurons. We asked how such connections could shape cortical responses to olfactory lateral olfactory tract (LOT) inputs. For this, we constructed a computational network model of anterior piriform cortex with 2000 multicompartment, multiconductance neurons (500 semilunar, 1000 layer 2 and 500 layer 3 pyramids; 200 superficial interneurons of two types; 500 deep interneurons of three types; 500 LOT afferents), incorporating published and unpublished data. With a given distribution of LOT firing patterns, and increasing the strength of recurrent excitation, a small number of firing patterns were observed in pyramidal cell networks: first, sparse firings; then temporally and spatially concentrated epochs of action potentials, wherein each neuron fires one or two spikes; then more synchronized events, associated with bursts of action potentials in some pyramidal neurons. We suggest that one function of anterior piriform cortex is to transform ongoing streams of input spikes into temporally focused spike patterns, called here "cell assemblies", that are salient for downstream projection areas.
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Affiliation(s)
- Roger D Traub
- AI Foundations, IBM T.J. Watson Research Center, Yorktown Heights, NY10598, USA
| | - Yuhai Tu
- AI Foundations, IBM T.J. Watson Research Center, Yorktown Heights, NY10598, USA
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16
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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: 14] [Impact Index Per Article: 4.7] [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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17
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Donoshita Y, Choi US, Ban H, Kida I. Assessment of olfactory information in the human brain using 7-Tesla functional magnetic resonance imaging. Neuroimage 2021; 236:118212. [PMID: 34082117 DOI: 10.1016/j.neuroimage.2021.118212] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 05/13/2021] [Accepted: 05/25/2021] [Indexed: 10/21/2022] Open
Abstract
Olfaction could prove to be an early marker of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. To use olfaction for disease diagnosis, elucidating the standard olfactory functions in healthy humans is necessary. However, the olfactory function in the human brain is less frequently assessed because of methodological difficulties associated with olfactory-related cerebral areas. Using ultra-high fields (UHF), functional magnetic resonance imaging (fMRI) with high spatial resolution and sensitivity may allow for the measurement of activation in the cerebral areas. This study aimed to apply 7-Tesla fMRI to assess olfactory function in the human brain by exposing individuals to four different odorants for 8 s. We found that olfactory stimulation mainly activated the piriform and orbitofrontal cortex in addition to the amygdala. Among these regions, univariate fMRI analysis indicated that subjective odor intensity significantly correlated with the averaged fMRI signals in the piriform cortex but not with subjective hedonic tone in any region. In contrast, multivariate fMRI analysis showed that subjective hedonic tone could be discriminated from the fMRI response patterns in the posterior orbitofrontal cortex. Thus, the piriform cortex is mainly associated with subjective odor intensity, whereas the posterior orbitofrontal cortex are involved in the discrimination of the subjective hedonic tone of the odorant. UHF-fMRI may be useful for assessing olfactory function in the human brain.
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Affiliation(s)
- Yuka Donoshita
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Osaka 565-0871, Japan; Daikin Industries, Ltd., Settsu, Osaka 566-8585, Japan
| | - Uk-Su Choi
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroshi Ban
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ikuhiro Kida
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan.
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18
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Midroit M, Chalençon L, Renier N, Milton A, Thevenet M, Sacquet J, Breton M, Forest J, Noury N, Richard M, Raineteau O, Ferdenzi C, Fournel A, Wesson DW, Bensafi M, Didier A, Mandairon N. Neural processing of the reward value of pleasant odorants. Curr Biol 2021; 31:1592-1605.e9. [PMID: 33607032 DOI: 10.1016/j.cub.2021.01.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023]
Abstract
Pleasant odorants are represented in the posterior olfactory bulb (pOB) in mice. How does this hedonic information generate odor-motivated behaviors? Using optogenetics, we report here that stimulating the representation of pleasant odorants in a sensory structure, the pOB, can be rewarding, self-motivating, and is accompanied by ventral tegmental area activation. To explore the underlying neural circuitry downstream of the olfactory bulb (OB), we use 3D high-resolution imaging and optogenetics and determine that the pOB preferentially projects to the olfactory tubercle, whose increased activity is related to odorant attraction. We further show that attractive odorants act as reinforcers in dopamine-dependent place preference learning. Finally, we extend those findings to humans, who exhibit place preference learning and an increase BOLD signal in the olfactory tubercle in response to attractive odorants. Thus, strong and persistent attraction induced by some odorants is due to a direct gateway from the pOB to the reward system.
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Affiliation(s)
- Maëllie Midroit
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Laura Chalençon
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Nicolas Renier
- Sorbonne Universités, Paris Brain Institute, ICM, Inserm, CNRS, Paris, France
| | - Adrianna Milton
- Department of Neurosciences, Case Western Reserve University, 2109 Adelbert Road, Cleveland, OH 44106, USA
| | - Marc Thevenet
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Joëlle Sacquet
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Marine Breton
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Jérémy Forest
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Norbert Noury
- CNRS, UMR5270, Institute Nanotechnology Lyon, Biomedical Sensors Group, University of Lyon 1, Villeurbanne 69621, France
| | - Marion Richard
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Olivier Raineteau
- University Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France
| | - Camille Ferdenzi
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Arnaud Fournel
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Daniel W Wesson
- Department of Pharmacology & Therapeutics, University of Florida, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Moustafa Bensafi
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Anne Didier
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France
| | - Nathalie Mandairon
- CNRS, UMR 5292, INSERM, U1028, Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon 69000, France; University Lyon, Lyon, 69000, France; University Lyon 1, Villeurbanne 69000, France.
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19
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Olfactory encoding within the insect antennal lobe: The emergence and role of higher order temporal correlations in the dynamics of antennal lobe spiking activity. J Theor Biol 2021; 522:110700. [PMID: 33819477 DOI: 10.1016/j.jtbi.2021.110700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 11/22/2022]
Abstract
In this review, we focus on the antennal lobe (AL) of three insect species - the fruit fly, sphinx moth, and locust. We first review the experimentally elucidated anatomy and physiology of the early olfactory system of each species; empirical studies of AL activity, however, often focus on assessing firing rates (averaged over time scales of about 100 ms), and hence the AL odor code is often analyzed in terms of a temporally evolving vector of firing rates. However, such a perspective necessarily misses the possibility of higher order temporal correlations in spiking activity within a single cell and across multiple cells over shorter time scales (of about 10 ms). Hence, we then review our prior theoretical work, where we constructed biophysically detailed, species-specific AL models within the fly, moth, and locust, finding that in each case higher order temporal correlations in spiking naturally emerge from model dynamics (i.e., without a prioriincorporation of elements designed to produce correlated activity). We therefore use our theoretical work to argue the perspective that temporal correlations in spiking over short time scales, which have received little experimental attention to-date, may provide valuable coding dimensions (complementing the coding dimensions provided by the vector of firing rates) that nature has exploited in the encoding of odors within the AL. We further argue that, if the AL does indeed utilize temporally correlated activity to represent odor information, such an odor code could be naturally and easily deciphered within the Mushroom Body.
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20
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Ryu B, Nagappan S, Santos-Valencia F, Lee P, Rodriguez E, Lackie M, Takatoh J, Franks KM. Chronic loss of inhibition in piriform cortex following brief, daily optogenetic stimulation. Cell Rep 2021; 35:109001. [PMID: 33882304 PMCID: PMC8102022 DOI: 10.1016/j.celrep.2021.109001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 12/10/2020] [Accepted: 03/24/2021] [Indexed: 12/02/2022] Open
Abstract
It is well established that seizures beget seizures, yet the cellular processes that underlie progressive epileptogenesis remain unclear. Here, we use optogenetics to briefly activate targeted populations of mouse piriform cortex (PCx) principal neurons in vivo. After just 3 or 4 days of stimulation, previously subconvulsive stimuli trigger massive, generalized seizures. Highly recurrent allocortices are especially prone to “optokindling.” Optokindling upsets the balance of recurrent excitation and feedback inhibition. To understand how this balance is disrupted, we then selectively reactivate the same neurons in vitro. Surprisingly, we find no evidence of heterosynaptic potentiation; instead, we observe a marked, pathway-specific decrease in feedback inhibition. We find no loss of inhibitory interneurons; rather, decreased GABA synthesis in feedback inhibitory neurons appears to underlie weakened inhibition. Optokindling will allow precise identification of the molecular processes by which brain activity patterns can progressively and pathologically disrupt the balance of cortical excitation and inhibition. Ryu et al. use optogenetics to briefly activate principal neurons in mouse piriform cortex. After 4 days, previously innocuous stimuli evoke massive, generalized seizures. “Optokindling” does not strengthen recurrent excitation; instead, it weakens feedback inhibition by decreasing synaptic cleft GABA concentrations and slowing vesicle refilling, consistent with decreased GABA synthesis.
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Affiliation(s)
- Brendan Ryu
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | | | | | - Psyche Lee
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Erica Rodriguez
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Meredith Lackie
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Jun Takatoh
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, NC 27705, USA.
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21
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Kjelvik G, Evensmoen HR, Hummel T, Engedal K, Selbæk G, Saltvedt I, Håberg AK. The Human Brain Representation of Odor Identification in Amnestic Mild Cognitive Impairment and Alzheimer's Dementia of Mild Degree. Front Neurol 2021; 11:607566. [PMID: 33519686 PMCID: PMC7838677 DOI: 10.3389/fneur.2020.607566] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/02/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Odor identification (OI) ability is a suggested early biomarker of Alzheimer's disease. In this study, we investigated brain activity within the brain's olfactory network associated with OI in patients with amnestic mild cognitive impairment (aMCI) and mild Alzheimer's dementia (mAD) to uncover the neuronal basis of this impairment. Materials and Methods: Patients with aMCI (n = 11) or mAD (n = 6) and 28 healthy older adults underwent OI functional MRI (fMRI) at 3T, OI, odor discrimination, and cognitive tests and apolipoprotein-e4 (APOE4) genotyping. Eleven patients had cerebrospinal fluid (CSF) analyzed. Those with aMCI were followed for 2 years to examine conversion to dementia. Results: The aMCI/mAD group performed significantly worse on all OI tests and the odor discrimination test compared to controls. The aMCI/mAD group had reduced activation in the right anterior piriform cortex compared to the controls during OI fMRI [Gaussian random field (GRF) corrected cluster threshold, p < 0.05]. This group difference remained after correcting for age, sex education, and brain parenchymal fraction. This difference in piriform activity was driven primarily by differences in odor discrimination ability and to a lesser extent by OI ability. There was no group by odor discrimination/identification score interaction on brain activity. Across both groups, only odor discrimination score was significantly associated with brain activity located to the right piriform cortex. Brain activity during OI was not associated with Mini Mental Status Examination scores. At the group level, the aMCI/mAD group activated only the anterior insula, while the control group had significant activation within all regions of the olfactory network during OI fMRI. There was no association between brain activity during OI fMRI and total beta-amyloid levels in the CSF in the aMCI/mAD group. Conclusion: The OI impairment in aMCI/mAD patients is associated with significantly reduced activity in the piriform cortex compared to controls. Activation of downstream regions within the olfactory network is also significantly affected in the aMCI/mAD group, except the anterior insula, which is impinged late in the course of Alzheimer's disease. OI tests thus reflect Alzheimer's disease pathology in olfactory brain structures.
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Affiliation(s)
- Grete Kjelvik
- Norwegian National Advisory Unit on Ageing and Health (Ageing and Health), Tønsberg, Norway.,Department of Radiology and Nuclear Medicine, St. Olavs Hospital (Norwegian National Advisory Unit for Functional Magnetic Resonance Imaging), University Hospital of Trondheim, Trondheim, Norway
| | - Hallvard R Evensmoen
- Department of Radiology and Nuclear Medicine, St. Olavs Hospital (Norwegian National Advisory Unit for Functional Magnetic Resonance Imaging), University Hospital of Trondheim, Trondheim, Norway.,Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
| | - Knut Engedal
- Norwegian National Advisory Unit on Ageing and Health (Ageing and Health), Tønsberg, Norway
| | - Geir Selbæk
- Norwegian National Advisory Unit on Ageing and Health (Ageing and Health), Tønsberg, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway
| | - Ingvild Saltvedt
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Geriatrics, Clinic of Medicine, St. Olavs Hospital, University Hospital of Trondheim, Trondheim, Norway
| | - Asta K Håberg
- Department of Radiology and Nuclear Medicine, St. Olavs Hospital (Norwegian National Advisory Unit for Functional Magnetic Resonance Imaging), University Hospital of Trondheim, Trondheim, Norway.,Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway
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22
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Arakawa H. Dynamic regulation of oxytocin neuronal circuits in the sequential processes of prosocial behavior in rodent models. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100011. [PMID: 36246512 PMCID: PMC9559098 DOI: 10.1016/j.crneur.2021.100011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/08/2021] [Accepted: 03/31/2021] [Indexed: 12/16/2022] Open
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23
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Cecchini MP, Riello M, Sandri A, Zanini A, Fiorio M, Tinazzi M. Smell and taste dissociations in the modulation of tonic pain perception induced by a capsaicin cream application. Eur J Pain 2020; 24:1946-1955. [PMID: 32780473 DOI: 10.1002/ejp.1644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pain is a subjective experience characterized by sensory (intensity) and emotional (unpleasantness) aspects. Although literature reports behavioural effects on pain due to smell and taste influence, to our knowledge the relationship between tonic pain induced by a capsaicin cream and these chemosensory systems has never been explored before. The aim of this study was to investigate the modulation of olfactory and gustatory substances having different valence on tonic pain perception mediated by a capsaicin cream application. METHODS Sixty healthy volunteers were included in two separated experiments (N = 30 smell; N = 30 taste) and underwent different valence smell and taste stimulations, while receiving painful stimuli. Perception of pain intensity (the sensory component) and unpleasantness (the affective component) was measured with a numerical rating scale, both during the two aforementioned experiments. RESULTS Pain unpleasantness rating showed differences only in the smell experiment between the two odourous conditions. In particular, pleasant odour induced lower ratings of pain unpleasantness, while no significant results were found for intensity. Regarding taste, we could not observe significant effects nor for pain unpleasantness or intensity. CONCLUSIONS These findings highlight the potential role of pleasant odours in influencing the affective aspects of pain perception induced by this kind of tonic pain. Such evidence might provide new insight for using chemosensory substances as analgesics for modulating the cognitive aspects of neuropathic pain. SIGNIFICANCE This work shows the effect of smell on the emotional component of tonic pain, experimentally induced by capsaicin cream application. Previous literature investigated tonic pain in interaction with smell and/or taste stimuli, but mainly with physical methods such as temperature. Our findings add new information in this field, contributing to a deeper insight on the role of olfaction on this particular kind of tonic pain perception. This approach could open to new investigations aimed to consider odours for pain management.
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Affiliation(s)
- Maria Paola Cecchini
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Marianna Riello
- Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Angela Sandri
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Alice Zanini
- Anatomy and Histology Section, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mirta Fiorio
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Michele Tinazzi
- Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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24
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Wang PY, Boboila C, Chin M, Higashi-Howard A, Shamash P, Wu Z, Stein NP, Abbott LF, Axel R. Transient and Persistent Representations of Odor Value in Prefrontal Cortex. Neuron 2020; 108:209-224.e6. [PMID: 32827456 DOI: 10.1016/j.neuron.2020.07.033] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 03/10/2020] [Accepted: 07/24/2020] [Indexed: 11/19/2022]
Abstract
The representation of odor in olfactory cortex (piriform) is distributive and unstructured and can only be afforded behavioral significance upon learning. We performed 2-photon imaging to examine the representation of odors in piriform and in two downstream areas, the orbitofrontal cortex (OFC) and the medial prefrontal cortex (mPFC), as mice learned olfactory associations. In piriform, we observed that odor responses were largely unchanged during learning. In OFC, 30% of the neurons acquired robust responses to conditioned stimuli (CS+) after learning, and these responses were gated by internal state and task context. Moreover, direct projections from piriform to OFC can be entrained to elicit learned olfactory behavior. CS+ responses in OFC diminished with continued training, whereas persistent representations of both CS+ and CS- odors emerged in mPFC. Optogenetic silencing indicates that these two brain structures function sequentially to consolidate the learning of appetitive associations.
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Affiliation(s)
- Peter Y Wang
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Cristian Boboila
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Matthew Chin
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Alexandra Higashi-Howard
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Philip Shamash
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Zheng Wu
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Nicole P Stein
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - L F Abbott
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Richard Axel
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA.
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25
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Blazing RM, Franks KM. Odor coding in piriform cortex: mechanistic insights into distributed coding. Curr Opin Neurobiol 2020; 64:96-102. [PMID: 32422571 DOI: 10.1016/j.conb.2020.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/01/2020] [Indexed: 10/24/2022]
Abstract
Olfaction facilitates a large variety of animal behaviors such as feeding, mating, and communication. Recent work has begun to reveal the logic of odor transformations that occur throughout the olfactory system to form the odor percept. In this review, we describe the coding principles and mechanisms by which the piriform cortex and other olfactory areas encode three key odor features: odor identity, intensity, and valence. We argue that the piriform cortex produces a multiplexed odor code that allows non-interfering representations of distinct features of the odor stimulus to facilitate odor recognition and learning, which ultimately drives behavior.
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Affiliation(s)
- Robin M Blazing
- Department of Neurobiology, Duke University Medical School, Durham, NC, 27705, United States
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, NC, 27705, United States.
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26
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Rapid Learning of Odor-Value Association in the Olfactory Striatum. J Neurosci 2020; 40:4335-4347. [PMID: 32321744 DOI: 10.1523/jneurosci.2604-19.2020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 03/30/2020] [Accepted: 04/06/2020] [Indexed: 11/21/2022] Open
Abstract
Rodents can successfully learn multiple novel stimulus-response associations after only a few repetitions when the contingencies predict reward. The circuits modified during such reinforcement learning to support decision-making are not known, but the olfactory tubercle (OT) and posterior piriform cortex (pPC) are candidates for decoding reward category from olfactory sensory input and relaying this information to cognitive and motor areas. Through single-cell recordings in behaving male and female C57BL/6 mice, we show here that an explicit representation for reward category emerges in the OT within minutes of learning a novel odor-reward association, whereas the pPC lacks an explicit representation even after weeks of overtraining. The explicit reward category representation in OT is visible in the first sniff (50-100 ms) of an odor on each trial, and precedes the motor action. Together, these results suggest that the coding of stimulus information required for reward prediction does not occur within olfactory cortex, but rather in circuits involving the olfactory striatum.SIGNIFICANCE STATEMENT Rodents are olfactory specialists and can use odors to learn contingencies quickly and well. We have found that mice can readily learn to place multiple odors into rewarded and unrewarded categories. Once they have learned the rule, they can do such categorization in a matter of minutes (<10 trials). We found that neural activity in olfactory cortex largely reflects sensory coding, with very little explicit information about categories. By contrast, neural activity in a brain region in the ventral striatum is rapidly modified in a matter of minutes to reflect reward category. Our experiments set up a paradigm for studying rapid sensorimotor reinforcement in a circuit that is right at the interface of sensory input and reward areas.
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27
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Lane G, Zhou G, Noto T, Zelano C. Assessment of direct knowledge of the human olfactory system. Exp Neurol 2020; 329:113304. [PMID: 32278646 DOI: 10.1016/j.expneurol.2020.113304] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/13/2020] [Accepted: 04/08/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Gregory Lane
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA.
| | - Guangyu Zhou
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA.
| | - Torben Noto
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Christina Zelano
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA
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28
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Glutamatergic Neurons in the Piriform Cortex Influence the Activity of D1- and D2-Type Receptor-Expressing Olfactory Tubercle Neurons. J Neurosci 2019; 39:9546-9559. [PMID: 31628176 DOI: 10.1523/jneurosci.1444-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 11/21/2022] Open
Abstract
Sensory cortices process stimuli in manners essential for perception. Very little is known regarding interactions between olfactory cortices. The piriform "primary" olfactory cortex, especially its anterior division (aPCX), extends dense association fibers into the ventral striatum's olfactory tubercle (OT), yet whether this corticostriatal pathway is capable of shaping OT activity, including odor-evoked activity, is unknown. Further unresolved is the synaptic circuitry and the spatial localization of OT-innervating PCX neurons. Here we build upon standing literature to provide some answers to these questions through studies in mice of both sexes. First, we recorded the activity of OT neurons in awake mice while optically stimulating principal neurons in the aPCX and/or their association fibers in the OT while the mice were delivered odors. This uncovered evidence that PCX input indeed influences OT unit activity. We then used patch-clamp recordings and viral tracing to determine the connectivity of aPCX neurons upon OT neurons expressing dopamine receptor types D1 or D2, two prominent cell populations in the OT. These investigations uncovered that both populations of neurons receive monosynaptic inputs from aPCX glutamatergic neurons. Interestingly, this input originates largely from the ventrocaudal aPCX. These results shed light on some of the basic physiological properties of this pathway and the cell-types involved and provide a foundation for future studies to identify, among other things, whether this pathway has implications for perception.SIGNIFICANCE STATEMENT Sensory cortices interact to process stimuli in manners considered essential for perception. Very little is known regarding interactions between olfactory cortices. The present study sheds light on some of the basic physiological properties of a particular intercortical pathway in the olfactory system and provides a foundation for future studies to identify, among other things, whether this pathway has implications for perception.
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29
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Bhutani S, Howard JD, Reynolds R, Zee PC, Gottfried J, Kahnt T. Olfactory connectivity mediates sleep-dependent food choices in humans. eLife 2019; 8:49053. [PMID: 31591965 PMCID: PMC6783266 DOI: 10.7554/elife.49053] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/03/2019] [Indexed: 01/15/2023] Open
Abstract
Sleep deprivation has marked effects on food intake, shifting food choices toward energy-dense options. Here we test the hypothesis that neural processing in central olfactory circuits, in tandem with the endocannabinoid system (ECS), plays a key role in mediating this relationship. We combined a partial sleep-deprivation protocol, pattern-based olfactory neuroimaging, and ad libitum food intake to test how central olfactory mechanisms alter food intake after sleep deprivation. We found that sleep restriction increased levels of the ECS compound 2-oleoylglycerol (2-OG), enhanced encoding of food odors in piriform cortex, and shifted food choices toward energy-dense food items. Importantly, the relationship between changes in 2-OG and food choices was formally mediated by odor-evoked connectivity between the piriform cortex and insula, a region involved in integrating feeding-related signals. These findings describe a potential neurobiological pathway by which state-dependent changes in the ECS may modulate chemosensory processing to regulate food choices. People who do not get enough sleep often start to favor sweet and fatty foods, which contributes to weight gain. While the exact mechanisms are still unknown, lack of sleep seems to change food preferences by influencing the levels of molecules that regulate food intake. In particular, it could have an effect on the endocannabinoid system, a complex network of molecules in the nervous system that controls biological processes such as appetite. The sense of smell is also tightly linked to how and what organisms choose to eat. Recent experiments indicate that in rodents, endocannabinoids enhance food intake by influencing the activity of the brain areas that process odors. However, it is still unclear whether the brain regions that process odors play a similar role in humans. To investigate, Bhutani et al. examined the impact of a four-hour night’s sleep on 25 healthy human volunteers. Blood analyses showed that after a short night, individuals had increased amounts of 2-oleoylglycerol, a molecule that is part of the endocannabinoid system. When sleep-deprived people were given the choice to eat whatever they wanted, those with greater levels of 2-oleoylglycerol preferred food higher in energy. Bhutani et al. also imaged the volunteers’ brains to examine whether these changes were connected to modifications in the way the brain processed smells. This revealed that, in people who did not sleep enough, an odor-processing region called the piriform cortex was encoding smells more strongly. The piriform cortex is connected to another region, the insula, which integrates information about the state of the body to control food intake. Lack of sleep altered this connection, and this was associated with a preference for high-energy food. In addition, further analysis showed that changes in the amounts of 2-oleoylglycerol were linked to modifications in the connection between the two brain areas. Taken together, these results suggest that sleep deprivation influences the endocannabinoid system, which in turn alters the connection between piriform and insular cortex, leading to a shift toward foods which are high in calories. In the United States alone, one in three people sleep less than six hours a night. Learning more about how sleep deprivation affects brain pathways and food choice may help scientists to develop new drugs or behavioral therapies for conditions like obesity.
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Affiliation(s)
- Surabhi Bhutani
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,School of Exercise and Nutritional Sciences, College of Health and Human Services, San Diego State University, San Diego, United States
| | - James D Howard
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Rachel Reynolds
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Phyllis C Zee
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jay Gottfried
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Psychology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, United States
| | - Thorsten Kahnt
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Psychology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, United States
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30
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Zhou G, Lane G, Cooper SL, Kahnt T, Zelano C. Characterizing functional pathways of the human olfactory system. eLife 2019; 8:47177. [PMID: 31339489 PMCID: PMC6656430 DOI: 10.7554/elife.47177] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/09/2019] [Indexed: 11/23/2022] Open
Abstract
The central processing pathways of the human olfactory system are not fully understood. The olfactory bulb projects directly to a number of cortical brain structures, but the distinct networks formed by projections from each of these structures to the rest of the brain have not been well-defined. Here, we used functional magnetic resonance imaging and k-means clustering to parcellate human primary olfactory cortex into clusters based on whole-brain functional connectivity patterns. Resulting clusters accurately corresponded to anterior olfactory nucleus, olfactory tubercle, and frontal and temporal piriform cortices, suggesting dissociable whole-brain networks formed by the subregions of primary olfactory cortex. This result was replicated in an independent data set. We then characterized the unique functional connectivity profiles of each subregion, producing a map of the large-scale processing pathways of the human olfactory system. These results provide insight into the functional and anatomical organization of the human olfactory system.
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Affiliation(s)
- Guangyu Zhou
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Gregory Lane
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Shiloh L Cooper
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Thorsten Kahnt
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Psychology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, United States
| | - Christina Zelano
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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31
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Scaling Principles of Distributed Circuits. Curr Biol 2019; 29:2533-2540.e7. [PMID: 31327712 DOI: 10.1016/j.cub.2019.06.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/21/2019] [Accepted: 06/17/2019] [Indexed: 12/17/2022]
Abstract
Identifying shared quantitative features of a neural circuit across species is important for 3 reasons. Often expressed in the form of power laws and called scaling relationships [1, 2], they reveal organizational principles of circuits, make insights gleaned from model systems widely applicable, and explain circuit performance and function, e.g., visual circuits [3, 4]. The visual circuit is topographic [5, 6], wherein retinal neurons target and activate predictable spatial loci in primary visual cortex. The brain, however, contains many circuits, where neuronal targets and activity are unpredictable and distributed throughout the circuit, e.g., olfactory circuits, in which glomeruli (or mitral cells) in the olfactory bulb synapse with neurons distributed throughout the piriform cortex [7-10]. It is unknown whether such circuits, which we term distributed circuits, are scalable. To determine whether distributed circuits scale, we obtained quantitative descriptions of the olfactory bulb and piriform cortex in six mammals using stereology techniques and light microscopy. Two conserved features provide evidence of scalability. First, the number of piriform neurons n and bulb glomeruli g scale as n∼g3/2. Second, the average number of synapses between a bulb glomerulus and piriform neuron is invariant at one. Using theory and modeling, we show that these two features preserve the discriminatory ability and precision of odor information across the olfactory circuit. As both abilities depend on circuit size, manipulating size provides evolution with a way to adapt a species to its niche without designing developmental programs de novo. These principles might apply to other distributed circuits like the hippocampus.
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32
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Strauch C, Manahan-Vaughan D. In the Piriform Cortex, the Primary Impetus for Information Encoding through Synaptic Plasticity Is Provided by Descending Rather than Ascending Olfactory Inputs. Cereb Cortex 2019; 28:764-776. [PMID: 29186359 DOI: 10.1093/cercor/bhx315] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Indexed: 12/27/2022] Open
Abstract
Information encoding by means of persistent changes in synaptic strength supports long-term information storage and memory in structures such as the hippocampus. In the piriform cortex (PC), that engages in the processing of associative memory, only short-term synaptic plasticity has been described to date, both in vitro and in anesthetized rodents in vivo. Whether the PC maintains changes in synaptic strength for longer periods of time is unknown: Such a property would indicate that it can serve as a repository for long-term memories. Here, we report that in freely behaving animals, frequency-dependent synaptic plasticity does not occur in the anterior PC (aPC) following patterned stimulation of the olfactory bulb (OB). Naris closure changed action potential properties of aPC neurons and enabled expression of long-term potentiation (LTP) by OB stimulation, indicating that an intrinsic ability to express synaptic plasticity is present. Odor discrimination and categorization in the aPC is supported by descending inputs from the orbitofrontal cortex (OFC). Here, OFC stimulation resulted in LTP (>4 h), suggesting that this structure plays an important role in promoting information encoding through synaptic plasticity in the aPC. These persistent changes in synaptic strength are likely to comprise a means through which long-term memories are encoded and/or retained in the PC.
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Affiliation(s)
- Christina Strauch
- Department of Neurophysiology, Medical Faculty.,International Graduate School for Neuroscience, Ruhr University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty.,International Graduate School for Neuroscience, Ruhr University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
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33
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Meissner-Bernard C, Dembitskaya Y, Venance L, Fleischmann A. Encoding of Odor Fear Memories in the Mouse Olfactory Cortex. Curr Biol 2019; 29:367-380.e4. [DOI: 10.1016/j.cub.2018.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 10/19/2018] [Accepted: 12/04/2018] [Indexed: 11/26/2022]
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34
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Bamji-Stocke S, Biggs BT, Samuelsen CL. Experience-dependent c-Fos expression in the primary chemosensory cortices of the rat. Brain Res 2018; 1701:189-195. [PMID: 30244018 PMCID: PMC6289795 DOI: 10.1016/j.brainres.2018.09.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/30/2018] [Accepted: 09/18/2018] [Indexed: 11/21/2022]
Abstract
Eating a new food is a unique event that guides future food choices. A key element for these choices is the perception of flavor (odor-taste associations), a multisensory process dependent upon taste and smell. The two primary cortical areas for taste and smell, gustatory cortex and piriform cortex, are thought to be crucial regions for processing and responding to odor-taste mixtures. To determine how previous experience impacts the primary chemosensory cortices, we compared the expression of the immediate early gene, c-Fos, between rats presented with a taste, an odor, or an odor-taste mixture for the first-time with rats that had many days of prior experience. Compared to rats with prior experience, we found that first-time sampling of all three chemosensory stimuli led to significantly greater c-Fos expression in gustatory cortex. In piriform cortex, only the novel chemosensory stimuli containing odors showed greater c-Fos expression. These results indicate that prior experience with taste, odor, or odor-taste stimuli habituates responses in the primary chemosensory cortices and adds further evidence supporting gustatory cortex as a fundamental node for the integration of gustatory and olfactory signals.
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Affiliation(s)
- Sanaya Bamji-Stocke
- Department of Anatomical Sciences and Neurobiology, University of Louisville, KY 40202, United States.
| | - Bradley T Biggs
- Department of Anatomical Sciences and Neurobiology, University of Louisville, KY 40202, United States
| | - Chad L Samuelsen
- Department of Anatomical Sciences and Neurobiology, University of Louisville, KY 40202, United States.
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35
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Srinivasan S, Stevens CF. The distributed circuit within the piriform cortex makes odor discrimination robust. J Comp Neurol 2018; 526:2725-2743. [PMID: 30014545 DOI: 10.1002/cne.24492] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 12/14/2022]
Abstract
Distributed circuits wherein connections between subcircuit components seem randomly distributed are common to the olfactory circuit, hippocampus, and cerebellum. In such circuits, activation patterns seem random too, showing no detectable spatial preference, and contrast with regions that have topographic connections between subcircuits and topographic activation patterns. Quantitative studies of topographic circuits in the neocortex have yielded common principles of organization. Whether distributed circuits share similar principles of organization is unknown because similar quantitative information is missing and understanding the way they encode information remains a challenge. We addressed these needs by providing a quantitative description of the mouse piriform cortex, a paleocortical distributed circuit that subserves olfaction. The quantitative information provided two insights. First, with a nearly parameter-free model of the olfactory circuit, we show that the piriform cortex robustly maintains odor information and discrimination ability present in the olfactory bulb. Second, the paleocortex is quantitatively different from the neocortex: it has a lower surface area density, which decreases from the anterior to posterior paleocortex contrasting with the uniform neuronal density of the neocortex. These insights might also apply to other distributed circuits.
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Affiliation(s)
- Shyam Srinivasan
- Salk Institute for Biological Studies, La Jolla, California.,Kavli Institute for Brain and Mind, University of California, San Diego, California
| | - Charles F Stevens
- Salk Institute for Biological Studies, La Jolla, California.,Kavli Institute for Brain and Mind, University of California, San Diego, California
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36
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Bolding KA, Franks KM. Recurrent cortical circuits implement concentration-invariant odor coding. Science 2018; 361:361/6407/eaat6904. [PMID: 30213885 DOI: 10.1126/science.aat6904] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 08/03/2018] [Indexed: 12/28/2022]
Abstract
Animals rely on olfaction to find food, attract mates, and avoid predators. To support these behaviors, they must be able to identify odors across different odorant concentrations. The neural circuit operations that implement this concentration invariance remain unclear. We found that despite concentration-dependence in the olfactory bulb (OB), representations of odor identity were preserved downstream, in the piriform cortex (PCx). The OB cells responding earliest after inhalation drove robust responses in sparse subsets of PCx neurons. Recurrent collateral connections broadcast their activation across the PCx, recruiting global feedback inhibition that rapidly truncated and suppressed cortical activity for the remainder of the sniff, discounting the impact of slower, concentration-dependent OB inputs. Eliminating recurrent collateral output amplified PCx odor responses rendered the cortex steeply concentration-dependent and abolished concentration-invariant identity decoding.
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Affiliation(s)
- Kevin A Bolding
- Department of Neurobiology, Duke University Medical School, Durham, NC, USA
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, NC, USA.
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37
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Ishii KK, Touhara K. Neural circuits regulating sexual behaviors via the olfactory system in mice. Neurosci Res 2018; 140:59-76. [PMID: 30389572 DOI: 10.1016/j.neures.2018.10.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/25/2018] [Accepted: 10/15/2018] [Indexed: 01/17/2023]
Abstract
Reproduction is essential for any animal species. Reproductive behaviors, or sexual behaviors, are largely shaped by external sensory cues exchanged during sexual interaction. In many animals, including rodents, olfactory cues play a critical role in regulating sexual behavior. What exactly these olfactory cues are and how they impact animal behavior have been a central question in the field. Over the past few decades, many studies have dedicated to identifying an active compound that elicits sexual behavior from crude olfactory components. The identified substance has served as a tool to dissect the sensory processing mechanisms in the olfactory systems. In addition, recent advances in genetic engineering, and optics and microscopic techniques have greatly expanded our knowledge of the neural mechanisms underlying the control of sexual behavior in mice. This review summarizes our current knowledge about how sexual behaviors are controlled by olfactory cues.
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Affiliation(s)
- Kentaro K Ishii
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan.
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38
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Differential inhibition of pyramidal cells and inhibitory interneurons along the rostrocaudal axis of anterior piriform cortex. Proc Natl Acad Sci U S A 2018; 115:E8067-E8076. [PMID: 30087186 DOI: 10.1073/pnas.1802428115] [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: 11/18/2022] Open
Abstract
The spatial representation of stimuli in sensory neocortices provides a scaffold for elucidating circuit mechanisms underlying sensory processing. However, the anterior piriform cortex (APC) lacks topology for odor identity as well as afferent and intracortical excitation. Consequently, olfactory processing is considered homogenous along the APC rostral-caudal (RC) axis. We recorded excitatory and inhibitory neurons in APC while optogenetically activating GABAergic interneurons along the RC axis. In contrast to excitation, we find opposing, spatially asymmetric inhibition onto pyramidal cells (PCs) and interneurons. PCs are strongly inhibited by caudal stimulation sites, whereas interneurons are strongly inhibited by rostral sites. At least two mechanisms underlie spatial asymmetries. Enhanced caudal inhibition of PCs is due to increased synaptic strength, whereas rostrally biased inhibition of interneurons is mediated by increased somatostatin-interneuron density. Altogether, we show differences in rostral and caudal inhibitory circuits in APC that may underlie spatial variation in odor processing along the RC axis.
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39
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Pardo GVE, Lucion AB, Calcagnotto ME. Postnatal development of inhibitory synaptic transmission in the anterior piriform cortex. Int J Dev Neurosci 2018; 71:1-9. [PMID: 30055229 DOI: 10.1016/j.ijdevneu.2018.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/09/2018] [Accepted: 07/23/2018] [Indexed: 02/06/2023] Open
Abstract
The morphological and functional development of inhibitory circuit in the anterior piriform cortex (aPC) during the first three postnatal weeks may be crucial for the development of odor preference learning in infant rodents. As first step toward testing this hypothesis, we examined the normal development of GABAergic synaptic transmission in the aPC of rat pups during the postnatal days (P) 5-8 and 14-17. Whole cell patch-clamp recordings of layer 2/3 (L2/3) aPC pyramidal cells revealed a significant increase in spontaneous (sIPSC) and miniature (mIPSC) inhibitory postsynaptic current frequencies and a decrease in mIPSC rise and decay-time constant at P14-P17. Moreover, as the development of neocortical inhibitory circuit can be driven by sensory experience, we recorded sIPSC and mIPSC onto L2/3 aPC pyramidal cells from unilateral naris-occluded animals. Early partial olfactory deprivation caused by naris occlusion do not affected the course of age-dependent increase IPSC frequency onto L2/3 aPC pyramidal cell. However, this age-dependent increase of sIPSC and mIPSC frequencies were lower on aPC pyramidal cells ipsilateral to the occlusion side. In addition, the age-dependent increase in sIPSC frequency and amplitude were more pronounced on aPC pyramidal cells contralateral to the occlusion. While mIPSC kinetics were not affected by age or olfactory deprivation, at P5-P8, the sIPSC decay-time constant on aPC pyramidal cells of both hemispheres of naris-occluded animals were significantly higher when compared to sham. These results demonstrated that the GABAergic synaptic transmission on the aPC changed during postnatal development by increasing inhibitory inputs on L2/3 pyramidal cells, with increment in frequency of both sIPSC and mIPSC and faster kinetics of mIPSC. Our data suggested that the maturation of GABAergic synaptic transmission was little affected by early partial olfactory deprivation. These results could contribute to unravel the mechanisms underlying the development of odor processing and olfactory preference learning.
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Affiliation(s)
- Grace Violeta Espinoza Pardo
- Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 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, Brazil
| | - Aldo Bolten Lucion
- Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 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, Brazil.
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40
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Non-imaged based method for matching brains in a common anatomical space for cellular imagery. J Neurosci Methods 2018; 304:136-145. [DOI: 10.1016/j.jneumeth.2018.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/06/2018] [Accepted: 04/07/2018] [Indexed: 11/18/2022]
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41
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Schaffer ES, Stettler DD, Kato D, Choi GB, Axel R, Abbott LF. Odor Perception on the Two Sides of the Brain: Consistency Despite Randomness. Neuron 2018; 98:736-742.e3. [PMID: 29706585 PMCID: PMC6026547 DOI: 10.1016/j.neuron.2018.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/03/2018] [Accepted: 04/03/2018] [Indexed: 11/22/2022]
Abstract
Neurons in piriform cortex receive input from a random collection of glomeruli, resulting in odor representations that lack the stereotypic organization of the olfactory bulb. We have performed in vivo optical imaging and mathematical modeling to demonstrate that correlations are retained in the transformation from bulb to piriform cortex, a feature essential for generalization across odors. Random connectivity also implies that the piriform representation of a given odor will differ among different individuals and across brain hemispheres in a single individual. We show that these different representations can nevertheless support consistent agreement about odor quality across a range of odors. Our model also demonstrates that, whereas odor discrimination and categorization require far fewer neurons than reside in piriform cortex, consistent generalization may require the full complement of piriform neurons.
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Affiliation(s)
- Evan S Schaffer
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
| | - Dan D Stettler
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Daniel Kato
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Gloria B Choi
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Richard Axel
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - L F Abbott
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
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42
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Stern M, Bolding KA, Abbott LF, Franks KM. A transformation from temporal to ensemble coding in a model of piriform cortex. eLife 2018; 7:34831. [PMID: 29595470 PMCID: PMC5902166 DOI: 10.7554/elife.34831] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/20/2018] [Indexed: 11/29/2022] Open
Abstract
Different coding strategies are used to represent odor information at various stages of the mammalian olfactory system. A temporal latency code represents odor identity in olfactory bulb (OB), but this temporal information is discarded in piriform cortex (PCx) where odor identity is instead encoded through ensemble membership. We developed a spiking PCx network model to understand how this transformation is implemented. In the model, the impact of OB inputs activated earliest after inhalation is amplified within PCx by diffuse recurrent collateral excitation, which then recruits strong, sustained feedback inhibition that suppresses the impact of later-responding glomeruli. We model increasing odor concentrations by decreasing glomerulus onset latencies while preserving their activation sequences. This produces a multiplexed cortical odor code in which activated ensembles are robust to concentration changes while concentration information is encoded through population synchrony. Our model demonstrates how PCx circuitry can implement multiplexed ensemble-identity/temporal-concentration odor coding.
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Affiliation(s)
- Merav Stern
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University, Jerusalem, Israel.,Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, United States
| | - Kevin A Bolding
- Department of Neurobiology, Duke University School of Medicine, Durham, United States
| | - L F Abbott
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, United States
| | - Kevin M Franks
- Department of Neurobiology, Duke University School of Medicine, Durham, United States
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43
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Mazo C, Grimaud J, Shima Y, Murthy VN, Lau CG. Distinct projection patterns of different classes of layer 2 principal neurons in the olfactory cortex. Sci Rep 2017; 7:8282. [PMID: 28811534 PMCID: PMC5558010 DOI: 10.1038/s41598-017-08331-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/07/2017] [Indexed: 11/16/2022] Open
Abstract
The broadly-distributed, non-topographic projections to and from the olfactory cortex may suggest a flat, non-hierarchical organization in odor information processing. Layer 2 principal neurons in the anterior piriform cortex (APC) can be divided into 2 subtypes: semilunar (SL) and superficial pyramidal (SP) cells. Although it is known that SL and SP cells receive differential inputs from the olfactory bulb (OB), little is known about their projections to other olfactory regions. Here, we examined axonal projections of SL and SP cells using a combination of mouse genetics and retrograde labeling. Retrograde tracing from the OB or posterior piriform cortex (PPC) showed that the APC projects to these brain regions mainly through layer 2b cells, and dual-labeling revealed many cells extending collaterals to both target regions. Furthermore, a transgenic mouse line specifically labeling SL cells showed that they send profuse axonal projections to olfactory cortical areas, but not to the OB. These findings support a model in which information flow from SL to SP cells and back to the OB is mediated by a hierarchical feedback circuit, whereas both SL and SP cells broadcast information to higher olfactory areas in a parallel manner.
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Affiliation(s)
- Camille Mazo
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA.,Ecole Normale Supérieure de Cachan, Université Paris-Saclay, F-94235, Cachan, France
| | - Julien Grimaud
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA.,Ecole Normale Supérieure de Cachan, Université Paris-Saclay, F-94235, Cachan, France
| | - Yasuyuki Shima
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA
| | - Venkatesh N Murthy
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA.
| | - C Geoffrey Lau
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA. .,Department of Biomedical Sciences and Centre for Biosystems, Neuroscience and Nanotechnology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong.
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Roland B, Deneux T, Franks KM, Bathellier B, Fleischmann A. Odor identity coding by distributed ensembles of neurons in the mouse olfactory cortex. eLife 2017; 6:e26337. [PMID: 28489003 PMCID: PMC5438249 DOI: 10.7554/elife.26337] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/29/2017] [Indexed: 11/18/2022] Open
Abstract
Olfactory perception and behaviors critically depend on the ability to identify an odor across a wide range of concentrations. Here, we use calcium imaging to determine how odor identity is encoded in olfactory cortex. We find that, despite considerable trial-to-trial variability, odor identity can accurately be decoded from ensembles of co-active neurons that are distributed across piriform cortex without any apparent spatial organization. However, piriform response patterns change substantially over a 100-fold change in odor concentration, apparently degrading the population representation of odor identity. We show that this problem can be resolved by decoding odor identity from a subpopulation of concentration-invariant piriform neurons. These concentration-invariant neurons are overrepresented in piriform cortex but not in olfactory bulb mitral and tufted cells. We therefore propose that distinct perceptual features of odors are encoded in independent subnetworks of neurons in the olfactory cortex.
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Affiliation(s)
- Benjamin Roland
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, Paris, France
| | - Thomas Deneux
- Unité de Neuroscience, Information et Complexité, Centre National de la Recherche Scientifique, UPR 3293, Gif-sur-Yvette, France
| | - Kevin M Franks
- Department of Neurobiology, Duke University, Durham, United States
| | - Brice Bathellier
- Unité de Neuroscience, Information et Complexité, Centre National de la Recherche Scientifique, UPR 3293, Gif-sur-Yvette, France
| | - Alexander Fleischmann
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, Paris, France
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45
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Bolding KA, Franks KM. Complementary codes for odor identity and intensity in olfactory cortex. eLife 2017; 6. [PMID: 28379135 PMCID: PMC5438247 DOI: 10.7554/elife.22630] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 04/01/2017] [Indexed: 12/18/2022] Open
Abstract
The ability to represent both stimulus identity and intensity is fundamental for perception. Using large-scale population recordings in awake mice, we find distinct coding strategies facilitate non-interfering representations of odor identity and intensity in piriform cortex. Simply knowing which neurons were activated is sufficient to accurately represent odor identity, with no additional information about identity provided by spike time or spike count. Decoding analyses indicate that cortical odor representations are not sparse. Odorant concentration had no systematic effect on spike counts, indicating that rate cannot encode intensity. Instead, odor intensity can be encoded by temporal features of the population response. We found a subpopulation of rapid, largely concentration-invariant responses was followed by another population of responses whose latencies systematically decreased at higher concentrations. Cortical inhibition transforms olfactory bulb output to sharpen these dynamics. Our data therefore reveal complementary coding strategies that can selectively represent distinct features of a stimulus. DOI:http://dx.doi.org/10.7554/eLife.22630.001
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Affiliation(s)
- Kevin A Bolding
- Department of Neurobiology, Duke University Medical School, Durham, United States
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, United States
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46
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Population Coding in an Innately Relevant Olfactory Area. Neuron 2017; 93:1180-1197.e7. [PMID: 28238549 DOI: 10.1016/j.neuron.2017.02.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/22/2016] [Accepted: 02/04/2017] [Indexed: 11/23/2022]
Abstract
Different olfactory cortical regions are thought to harbor distinct sensory representations, enabling each area to play a unique role in odor perception and behavior. In the piriform cortex (PCx), spatially dispersed sensory inputs evoke activity in distributed ensembles of neurons that act as substrates for odor learning. In contrast, the posterolateral cortical amygdala (plCoA) receives hardwired inputs that may link specific odor cues to innate olfactory behaviors. Here we show that despite stark differences in the patterning of plCoA and PCx inputs, odor-evoked neural ensembles in both areas are equally capable of discriminating odors, and exhibit similar odor tuning, reliability, and correlation structure. These results demonstrate that brain regions mediating odor-driven innate behaviors can, like brain areas involved in odor learning, represent odor objects using distributive population codes; these findings suggest both alternative mechanisms for the generation of innate odor-driven behaviors and additional roles for the plCoA in odor perception.
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47
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Yang J, Litscher G, Sun Z, Tang Q, Kishi K, Oda S, Takayanagi M, Sheng Z, Liu Y, Guo W, Zhang T, Wang L, Gaischek I, Litscher D, Lippe IT, Kuroda M. Quantitative analysis of axon collaterals of single pyramidal cells of the anterior piriform cortex of the guinea pig. BMC Neurosci 2017; 18:25. [PMID: 28178946 PMCID: PMC5299671 DOI: 10.1186/s12868-017-0342-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 01/24/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The role of the piriform cortex (PC) in olfactory information processing remains largely unknown. The anterior part of the piriform cortex (APC) has been the focus of cortical-level studies of olfactory coding, and associative processes have attracted considerable attention as an important part in odor discrimination and olfactory information processing. Associational connections of pyramidal cells in the guinea pig APC were studied by direct visualization of axons stained and quantitatively analyzed by intracellular biocytin injection in vivo. RESULTS The observations illustrated that axon collaterals of the individual cells were widely and spatially distributed within the PC, and sometimes also showed a long associational projection to the olfactory bulb (OB). The data showed that long associational axons were both rostrally and caudally directed throughout the PC, and the intrinsic associational fibers of pyramidal cells in the APC are omnidirectional connections in the PC. Within the PC, associational axons typically followed rather linear trajectories and irregular bouton distributions. Quantitative data of the axon collaterals of two pyramidal cells in the APC showed that the average length of axonal collaterals was 101 mm, out of which 79 mm (78% of total length) were distributed in the PC. The average number of boutons was 8926 and 7101, respectively, with 79% of the total number of boutons being distributed in the PC. The percentage of the total area of the APC and the posterior piriform cortex occupied by the average distribution region of the axon collaterals of two superficial pyramidal (SP) cells was about 18 and 5%, respectively. CONCLUSION Our results demonstrate that omnidirectional connection of pyramidal cells in the APC provides a substrate for recurrent processes. These findings indicate that the axon collaterals of SP cells in the PC could make synaptic contacts with all granule cells in the OB. This study provides the morphological evidence for understanding the mechanisms of information processing and associative memory in the APC.
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Affiliation(s)
- Junli Yang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan.
| | - Gerhard Litscher
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria.
| | - Zhongren Sun
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
| | - Qiang Tang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Kiyoshi Kishi
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Satoko Oda
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Masaaki Takayanagi
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Zemin Sheng
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
- Privatclinic Lassnitzhoehe, 8301, Lassnitzhoehe, Austria
| | - Yang Liu
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Wenhai Guo
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Ting Zhang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Lu Wang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Ingrid Gaischek
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Daniela Litscher
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Irmgard Th Lippe
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, 8036, Graz, Austria
| | - Masaru Kuroda
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
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48
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Maier JX. Single-neuron responses to intraoral delivery of odor solutions in primary olfactory and gustatory cortex. J Neurophysiol 2016; 117:1293-1304. [PMID: 28003413 DOI: 10.1152/jn.00802.2016] [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] [Received: 10/11/2016] [Revised: 11/30/2016] [Accepted: 12/15/2016] [Indexed: 11/22/2022] Open
Abstract
Smell plays a major role in our perception of food. Odorants released inside the mouth during consumption are combined with taste and texture qualities of a food to guide flavor preference learning and food choice behavior. Here, we built on recent physiological findings that implicated primary sensory cortex in multisensory flavor processing. Specifically, we used extracellular recordings in awake rats to characterize responses of single neurons in primary olfactory (OC) and gustatory cortex (GC) to intraoral delivery of odor solutions and compare odor responses to taste and plain water responses. The data reveal responses to olfactory, oral somatosensory, and gustatory qualities of intraoral stimuli in both OC and GC. Moreover, modality-specific responses overlap in time, indicating temporal convergence of multisensory, flavor-related inputs. The results extend previous work suggesting a role for primary OC in mediating influences of taste on smell that characterize flavor perception and point to an integral role for GC in olfactory processing.NEW & NOTEWORTHY Food perception is inherently multisensory, taking into account taste, smell, and texture qualities. However, the neural mechanisms underlying flavor perception remain unknown. Recording neural activity directly from the rat brain while animals consume multisensory flavor stimuli, we demonstrate that information about odor, taste, and mouthfeel of food converges on primary taste and smell cortex. The results suggest that processing of naturalistic, multisensory information involves an interacting network of primary sensory areas.
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Affiliation(s)
- Joost X Maier
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston Salem, North Carolina
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49
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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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50
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Marlin BJ, Froemke RC. Oxytocin modulation of neural circuits for social behavior. Dev Neurobiol 2016; 77:169-189. [PMID: 27626613 DOI: 10.1002/dneu.22452] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 01/04/2023]
Abstract
Oxytocin is a hypothalamic neuropeptide that has gained attention for the effects on social behavior. Recent findings shed new light on the mechanisms of oxytocin in synaptic plasticity and adaptively modifying neural circuits for social interactions such as conspecific recognition, pair bonding, and maternal care. Here, we review several of these newer studies on oxytocin in the context of previous findings, with an emphasis on social behavior and circuit plasticity in various brain regions shown to be enriched for oxytocin receptors. We provide a framework that highlights current circuit-level mechanisms underlying the widespread action of oxytocin. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 169-189, 2017.
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Affiliation(s)
- Bianca J Marlin
- Department of Neuroscience, Columbia University, New York, New York, 10032.,Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, New York, New York, 10032
| | - Robert C Froemke
- Department of Otolaryngology, Skirball Institute for Biomolecular Medicine, Neuroscience Institute, New York University School of Medicine, New York, New York.,Department of Neuroscience and Physiology Skirball Institute for Biomolecular Medicine, Neuroscience Institute New York University School of Medicine, New York, New York.,Center for Neural Science, New York University, New York, New York
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