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Naffaa MM. Neurogenesis dynamics in the olfactory bulb: deciphering circuitry organization, function, and adaptive plasticity. Neural Regen Res 2025; 20:1565-1581. [PMID: 38934393 DOI: 10.4103/nrr.nrr-d-24-00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. Moreover, the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased complexity and restructuring of neural network structures, as well as the addition of new granule granule cells that aid in olfactory adaptation. Additionally, the manuscript underscores the importance of employing precise methodologies to elucidate the specific roles of adult neurogenesis amidst conflicting data and varying experimental paradigms. Understanding these processes is essential for gaining insights into the complexities of olfactory function and behavior.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
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2
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Lucas A, Jaskir M, Sinha N, Pattnaik A, Mouchtaris S, Josyula M, Petillo N, Roth RW, Dikecligil GN, Bonilha L, Gottfried J, Gleichgerrcht E, Das S, Stein JM, Gugger JJ, Davis KA. Connectivity of the Piriform Cortex and its Implications in Temporal Lobe Epilepsy. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.07.21.24310778. [PMID: 39108505 PMCID: PMC11302608 DOI: 10.1101/2024.07.21.24310778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Background The piriform cortex has been implicated in the initiation, spread and termination of epileptic seizures. This understanding has extended to surgical management of epilepsy, where it has been shown that resection or ablation of the piriform cortex can result in better outcomes. How and why the piriform cortex may play such a crucial role in seizure networks is not well understood. To answer these questions, we investigated the functional and structural connectivity of the piriform cortex in both healthy controls and temporal lobe epilepsy (TLE) patients. Methods We studied a retrospective cohort of 55 drug-resistant unilateral TLE patients and 26 healthy controls who received structural and functional neuroimaging. Using seed-to-voxel connectivity we compared the normative whole-brain connectivity of the piriform to that of the hippocampus, a region commonly involved in epilepsy, to understand the differential contribution of the piriform to the epileptogenic network. We subsequently measured the inter-piriform coupling (IPC) to quantify similarities in the inter-hemispheric cortical functional connectivity profile between the two piriform cortices. We related differences in IPC in TLE back to aberrations in normative piriform connectivity, whole brain functional properties, and structural connectivity. Results We find that relative to the hippocampus, the piriform is functionally connected to the anterior insula and the rest of the salience ventral attention network (SAN). We also find that low IPC is a sensitive metric of poor surgical outcome (sensitivity: 85.71%, 95% CI: [19.12%, 99.64%]); and differences in IPC within TLE were related to disconnectivity and hyperconnectivity to the anterior insula and the SAN. More globally, we find that low IPC is associated with whole-brain functional and structural segregation, marked by decreased functional small-worldness and fractional anisotropy. Conclusions Our study presents novel insights into the functional and structural neural network alterations associated with this structure, laying the foundation for future work to carefully consider its connectivity during the presurgical management of epilepsy.
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Affiliation(s)
- Alfredo Lucas
- Perelman School of Medicine, University of Pennsylvania
- Department of Bioengineering, University of Pennsylvania
| | - Marc Jaskir
- Neuroscience Graduate Group, University of Pennsylvania
| | | | - Akash Pattnaik
- Department of Bioengineering, University of Pennsylvania
| | | | | | - Nina Petillo
- Department of Neurology, University of Pennsylvania
| | | | | | | | | | | | - Sandhitsu Das
- Department of Neurology, University of South Carolina
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3
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Okumura T, Kida I, Yokoi A, Nakai T, Nishimoto S, Touhara K, Okamoto M. Semantic context-dependent neural representations of odors in the human piriform cortex revealed by 7T MRI. Hum Brain Mapp 2024; 45:e26681. [PMID: 38656060 PMCID: PMC11041378 DOI: 10.1002/hbm.26681] [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: 07/03/2023] [Revised: 03/23/2024] [Accepted: 03/28/2024] [Indexed: 04/26/2024] Open
Abstract
Olfactory perception depends not only on olfactory inputs but also on semantic context. Although multi-voxel activity patterns of the piriform cortex, a part of the primary olfactory cortex, have been shown to represent odor perception, it remains unclear whether semantic contexts modulate odor representation in this region. Here, we investigated whether multi-voxel activity patterns in the piriform cortex change when semantic context modulates odor perception and, if so, whether the modulated areas communicate with brain regions involved in semantic and memory processing beyond the piriform cortex. We also explored regional differences within the piriform cortex, which are influenced by olfactory input and semantic context. We used 2 × 2 combinations of word labels and odorants that were perceived as congruent and measured piriform activity with a 1-mm isotropic resolution using 7T MRI. We found that identical odorants labeled with different words were perceived differently. This labeling effect was observed in multi-voxel activity patterns in the piriform cortex, as the searchlight decoding analysis distinguished identical odors with different labels for half of the examined stimulus pairs. Significant functional connectivity was observed between parts of the piriform cortex that were modulated by labels and regions associated with semantic and memory processing. While the piriform multi-voxel patterns evoked by different olfactory inputs were also distinguishable, the decoding accuracy was significant for only one stimulus pair, preventing definitive conclusions regarding the locational differences between areas influenced by word labels and olfactory inputs. These results suggest that multi-voxel patterns of piriform activity can be modulated by semantic context, possibly due to communication between the piriform cortex and the semantic and memory regions.
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Affiliation(s)
- Toshiki Okumura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of TokyoTokyoJapan
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT)OsakaJapan
| | - Ikuhiro Kida
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT)OsakaJapan
- Graduate School of Frontier Biosciences, Osaka UniversityOsakaJapan
| | - Atsushi Yokoi
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT)OsakaJapan
- Graduate School of Frontier Biosciences, Osaka UniversityOsakaJapan
| | - Tomoya Nakai
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT)OsakaJapan
| | - Shinji Nishimoto
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT)OsakaJapan
- Graduate School of Frontier Biosciences, Osaka UniversityOsakaJapan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of TokyoTokyoJapan
- International Research Center for Neurointelligence (WPI‐IRCN), Institutes for Advanced Study, The University of TokyoTokyoJapan
| | - Masako Okamoto
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of TokyoTokyoJapan
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4
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Sagar V, Shanahan LK, Zelano CM, Gottfried JA, Kahnt T. High-precision mapping reveals the structure of odor coding in the human brain. Nat Neurosci 2023; 26:1595-1602. [PMID: 37620443 PMCID: PMC10726579 DOI: 10.1038/s41593-023-01414-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 07/18/2023] [Indexed: 08/26/2023]
Abstract
Odor perception is inherently subjective. Previous work has shown that odorous molecules evoke distributed activity patterns in olfactory cortices, but how these patterns map on to subjective odor percepts remains unclear. In the present study, we collected neuroimaging responses to 160 odors from 3 individual subjects (18 h per subject) to probe the neural coding scheme underlying idiosyncratic odor perception. We found that activity in the orbitofrontal cortex (OFC) represents the fine-grained perceptual identity of odors over and above coarsely defined percepts, whereas this difference is less pronounced in the piriform cortex (PirC) and amygdala. Furthermore, the implementation of perceptual encoding models enabled us to predict olfactory functional magnetic resonance imaging responses to new odors, revealing that the dimensionality of the encoded perceptual spaces increases from the PirC to the OFC. Whereas encoding of lower-order dimensions generalizes across subjects, encoding of higher-order dimensions is idiosyncratic. These results provide new insights into cortical mechanisms of odor coding and suggest that subjective olfactory percepts reside in the OFC.
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Affiliation(s)
- Vivek Sagar
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Christina M Zelano
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jay A Gottfried
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Thorsten Kahnt
- National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA.
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5
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Wu T, Li S, Du D, Li R, Liu P, Yin Z, Zhang H, Qiao Y, Li A. Olfactory-auditory sensory integration in the lateral entorhinal cortex. Prog Neurobiol 2023; 221:102399. [PMID: 36581184 DOI: 10.1016/j.pneurobio.2022.102399] [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: 08/09/2022] [Revised: 12/02/2022] [Accepted: 12/19/2022] [Indexed: 12/27/2022]
Abstract
Multisensory integration plays an important role in animal cognition. Although many studies have focused on visual-auditory integration, studies on olfactory-auditory integration are rare. Here, we investigated neural activity patterns and odor decoding in the lateral entorhinal cortex (LEC) under uni-sensory and multisensory stimuli in awake, head-fixed mice. Using specific retrograde tracing, we verified that the LEC receives direct inputs from the primary auditory cortex (AC) and the medial geniculate body (MGB). Strikingly, we found that mitral/tufted cells (M/Ts) in the olfactory bulb (OB) and neurons in the LEC respond to both olfactory and auditory stimuli. Sound decreased the neural responses evoked by odors in both the OB and LEC, for both excitatory and inhibitory responses. Interestingly, significant changes in odor decoding performance and modulation of odor-evoked local field potentials (LFPs) were observed only in the LEC. These data indicate that the LEC is a critical center for olfactory-auditory multisensory integration, with direct projections from both olfactory and auditory centers.
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Affiliation(s)
- Tingting Wu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China; Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou 221004, China; Clinical Hearing Center, Department of Otorhinolaryngology - Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221006, China; Department of Otolaryngology, Eye, Ear, Nose and Throat Hospital, Shanghai Key Clinical Disciplines of Otorhinolaryngology, Fudan University, Shanghai 200031, China
| | - Shan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Deliang Du
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China; Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou 221004, China; Clinical Hearing Center, Department of Otorhinolaryngology - Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221006, China
| | - Ruochen Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Penglai Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Zhaoyang Yin
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China
| | - Hongxing Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou 221004, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou 221004, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, Xuzhou 221004, China
| | - Yuehua Qiao
- Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou 221004, China; Clinical Hearing Center, Department of Otorhinolaryngology - Head and Neck Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221006, China.
| | - Anan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou 221004, China.
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6
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Perszyk EE, Davis XS, Small DM. Olfactory decoding is positively associated with ad libitum food intake in sated humans. Appetite 2023; 180:106351. [PMID: 36270421 DOI: 10.1016/j.appet.2022.106351] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/06/2022]
Abstract
The role of olfaction in eating behavior and body weight regulation is controversial. Here we reanalyzed data from a previous functional magnetic resonance imaging study to test whether central olfactory coding is associated with hunger/satiety state, food intake, and change in body weight over one year in healthy human adults. Since odor quality and category are coded across distributed neural patterns that are not discernible with traditional univariate analyses, we used multi-voxel pattern analyses to decode patterns of brain activation to food versus nonfood odors. We found that decoding accuracies in the piriform cortex and amygdala were greater in the sated compared to hungry state. Sated decoding accuracies in these and other regions were also associated with post-scan ad libitum food intake, but not with weight change. These findings demonstrate that the fidelity of olfactory decoding is influenced by meal consumption and is associated with immediate food intake, but not longer-term body weight regulation.
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Affiliation(s)
- Emily E Perszyk
- Modern Diet and Physiology Research Center, New Haven, CT, 06510, USA; Yale University School of Medicine, Department of Psychiatry, New Haven, CT, 06510, USA.
| | - Xue S Davis
- Modern Diet and Physiology Research Center, New Haven, CT, 06510, USA; Yale University School of Medicine, Department of Psychiatry, New Haven, CT, 06510, USA
| | - Dana M Small
- Modern Diet and Physiology Research Center, New Haven, CT, 06510, USA; Yale University School of Medicine, Department of Psychiatry, New Haven, CT, 06510, USA; Yale University, Department of Psychology, New Haven, CT, 06510, USA.
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7
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Kulason S, Ratnanather JT, Miller MI, Kamath V, Hua J, Yang K, Ma M, Ishizuka K, Sawa A. A comparative neuroimaging perspective of olfaction and higher-order olfactory processing: on health and disease. Semin Cell Dev Biol 2022; 129:22-30. [PMID: 34462249 PMCID: PMC9900497 DOI: 10.1016/j.semcdb.2021.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/18/2021] [Indexed: 02/08/2023]
Abstract
Olfactory dysfunction is often the earliest indicator of disease in a range of neurological and psychiatric disorders. One tempting working hypothesis is that pathological changes in the peripheral olfactory system where the body is exposed to many adverse environmental stressors may have a causal role for the brain alteration. Whether and how the peripheral pathology spreads to more central brain regions may be effectively studied in rodent models, and there is successful precedence in experimental models for Parkinson's disease. It is of interest to study whether a similar mechanism may underlie the pathology of psychiatric illnesses, such as schizophrenia. However, direct comparison between rodent models and humans includes challenges under light of comparative neuroanatomy and experimental methodologies used in these two distinct species. We believe that neuroimaging modality that has been the main methodology of human brain studies may be a useful viewpoint to address and fill the knowledge gap between rodents and humans in this scientific question. Accordingly, in the present review article, we focus on brain imaging studies associated with olfaction in healthy humans and patients with neurological and psychiatric disorders, and if available those in rodents. We organize this review article at three levels: 1) olfactory bulb (OB) and peripheral structures of the olfactory system, 2) primary olfactory cortical and subcortical regions, and 3) associated higher-order cortical regions. This research area is still underdeveloped, and we acknowledge that further validation with independent cohorts may be needed for many studies presented here, in particular those with human subjects. Nevertheless, whether and how peripheral olfactory disturbance impacts brain function is becoming even a hotter topic in the ongoing COVID-19 pandemic, given the risk of long-term changes of mental status associated with olfactory infection of SARS-CoV-2. Together, in this review article, we introduce this underdeveloped but important research area focusing on its implications in neurological and psychiatric disorders, with several pioneered publications.
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Affiliation(s)
- Sue Kulason
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA; Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - J Tilak Ratnanather
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA; Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Michael I Miller
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA; Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Vidyulata Kamath
- Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jun Hua
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Kun Yang
- Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Johns Hopkins Schizophrenia Center, Baltimore, MD, USA
| | - Minghong Ma
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Koko Ishizuka
- Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Johns Hopkins Schizophrenia Center, Baltimore, MD, USA
| | - Akira Sawa
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Johns Hopkins Schizophrenia Center, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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8
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Echevarria-Cooper SL, Zhou G, Zelano C, Pestilli F, Parrish TB, Kahnt T. Mapping the Microstructure and Striae of the Human Olfactory Tract with Diffusion MRI. J Neurosci 2022; 42:58-68. [PMID: 34759031 PMCID: PMC8741165 DOI: 10.1523/jneurosci.1552-21.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/30/2021] [Accepted: 10/31/2021] [Indexed: 11/21/2022] Open
Abstract
The human sense of smell plays an important role in appetite and food intake, detecting environmental threats, social interactions, and memory processing. However, little is known about the neural circuity supporting its function. The olfactory tracts project from the olfactory bulb along the base of the frontal cortex, branching into several striae to meet diverse cortical regions. Historically, using diffusion magnetic resonance imaging (dMRI) to reconstruct the human olfactory tracts has been prevented by susceptibility and motion artifacts. Here, we used a dMRI method with readout segmentation of long variable echo-trains (RESOLVE) to minimize image distortions and characterize the human olfactory tracts in vivo We collected high-resolution dMRI data from 25 healthy human participants (12 male and 13 female) and performed probabilistic tractography using constrained spherical deconvolution (CSD). At the individual subject level, we identified the lateral, medial, and intermediate striae with their respective cortical connections to the piriform cortex and amygdala (AMY), olfactory tubercle (OT), and anterior olfactory nucleus (AON). We combined individual results across subjects to create a normalized, probabilistic atlas of the olfactory tracts. We then investigated the relationship between olfactory perceptual scores and measures of white matter integrity, including mean diffusivity (MD). Importantly, we found that olfactory tract MD negatively correlated with odor discrimination performance. In summary, our results provide a detailed characterization of the connectivity of the human olfactory tracts and demonstrate an association between their structural integrity and olfactory perceptual function.SIGNIFICANCE STATEMENT This study provides the first detailed in vivo description of the cortical connectivity of the three olfactory tract striae in the human brain, using diffusion magnetic resonance imaging (dMRI). Additionally, we show that tract microstructure correlates with performance on an odor discrimination task, suggesting a link between the structural integrity of the olfactory tracts and odor perception. Lastly, we generated a normalized probabilistic atlas of the olfactory tracts that may be used in future research to study its integrity in health and disease.
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Affiliation(s)
- Shiloh L Echevarria-Cooper
- Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
- The Graduate School, Northwestern University Interdepartmental Neuroscience (NUIN), Evanston, Illinois 60208
| | - Guangyu Zhou
- Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
| | - Christina Zelano
- Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
| | - Franco Pestilli
- Department of Psychology, The University of Texas at Austin, Austin, Texas 78712
- Center for Perceptual Systems, The University of Texas at Austin, Austin, Texas 78712
| | - Todd B Parrish
- Department of Radiology, Northwestern University, Chicago, Illinois 60611
| | - Thorsten Kahnt
- Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
- Department of Psychology, Northwestern University, Weinberg College of Arts and Sciences, Evanston, Illinois 60208
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9
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Callara AL, Greco A, Frasnelli J, Rho G, Vanello N, Scilingo EP. Cortical network and connectivity underlying hedonic olfactory perception. J Neural Eng 2021; 18. [PMID: 34547740 DOI: 10.1088/1741-2552/ac28d2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 09/21/2021] [Indexed: 12/15/2022]
Abstract
Objective.The emotional response to olfactory stimuli implies the activation of a complex cascade of events triggered by structures lying in the limbic system. However, little is known about how this activation is projected up to cerebral cortex and how different cortical areas dynamically interact each other.Approach.In this study, we acquired EEG from human participants performing a passive odor-perception task with odorants conveying positive, neutral and negative valence. A novel methodological pipeline integrating global field power (GFP), independent component analysis (ICA), dipole source localization was applied to estimate effective connectivity in the challenging scenario of single-trial low-synchronized stimulation.Main results.We identified the brain network and the neural paths, elicited at different frequency bands, i.e.θ(4-7Hz),α(8-12Hz)andβ(13-30Hz), involved in odor valence processing. This brain network includes the orbitofrontal cortex (OFC), the cingulate gyrus (CgG), the superior temporal gyrus (STG), the posterior cingulate cortex/precuneus (PCC/PCu) and the parahippocampal gyrus (PHG). It was analyzed using a time-varying multivariate autoregressive model to resolve time-frequency causal interactions. Specifically, the OFC acts as the main node for odor perception and evaluation of pleasant and unpleasant stimuli, whereas no specific path was observed for a neutral stimulus.Significance.The results introduce new evidences on the role of the OFC during hedonic perception and underpin its specificity during the odor valence assessment. Our findings suggest that, after the odor onset different, bidirectional interactions occur between the OFC and other brain regions associated with emotion recognition/categorization and memory according to the stimulus valence. This outcome unveils how the hedonic olfactory network dynamically changes based on odor valence.
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Affiliation(s)
- Alejandro Luis Callara
- Research Center 'E. Piaggio', School of Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.,Dipartimento di Ingegneria dell'Informazione, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy
| | - Alberto Greco
- Research Center 'E. Piaggio', School of Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.,Dipartimento di Ingegneria dell'Informazione, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy
| | - Johannes Frasnelli
- Département d'anatomie, Université du Québec à Trois-Rivières, 3351, boul. des Forges, C.P. 500, G9A 5H7
- Local 3439 L.-P, Trois-Rivières, Québec, Canada
| | - Gianluca Rho
- Dipartimento di Ingegneria dell'Informazione, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy
| | - Nicola Vanello
- Research Center 'E. Piaggio', School of Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.,Dipartimento di Ingegneria dell'Informazione, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy
| | - Enzo Pasquale Scilingo
- Research Center 'E. Piaggio', School of Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.,Dipartimento di Ingegneria dell'Informazione, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy
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10
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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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11
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Gorodisky L, Livne E, Weiss T, Weissbrod A, Weissgross R, Mishor E, Furman-Haran E, Sobel N. Odor Canopy: A Method for Comfortable Odorant Delivery in MRI. Chem Senses 2021; 46:6060058. [PMID: 33388762 PMCID: PMC8286093 DOI: 10.1093/chemse/bjaa085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) has become the leading method for measuring the human brain response to sensory stimuli. However, olfaction fMRI lags behind vision and audition fMRI for 2 primary reasons: First, the olfactory brain areas are particularly susceptible to imaging artifacts, and second, the olfactory stimulus is particularly difficult to control in the fMRI environment. A component of the latter is related to the odorant delivery human–machine interface, namely the point where odorants exit the dispensing apparatus to reach at the nose. Previous approaches relied on either nasal cannulas or nasal masks, each associated with particular drawbacks and discomforts. Here, we provide detailed descriptions and instructions for transforming the MRI head-coil into an olfactory microenvironment, or odor canopy, where odorants can be switched on and off in less than 150 ms without cannula or mask. In a proof-of-concept experiment, we demonstrate that odor canopy provides for clearly dissociable odorant presence and absence, with no nonolfactory cues. Moreover, we find that odor canopy is rated more comfortable than nasal mask, and we demonstrate that using odor canopy in the fMRI generates a typical olfactory brain response. We conclude in recommending this approach for minimized discomfort in fMRI of olfaction.
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Affiliation(s)
- Lior Gorodisky
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Ethan Livne
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Tali Weiss
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Aharon Weissbrod
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Reut Weissgross
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Eva Mishor
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Edna Furman-Haran
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
| | - Noam Sobel
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel.,Department of Neurobiology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
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12
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Mainland JD, Barlow LA, Munger SD, Millar SE, Vergara MN, Jiang P, Schwob JE, Goldstein BJ, Boye SE, Martens JR, Leopold DA, Bartoshuk LM, Doty RL, Hummel T, Pinto JM, Trimmer C, Kelly C, Pribitkin EA, Reed DR. Identifying Treatments for Taste and Smell Disorders: Gaps and Opportunities. Chem Senses 2020; 45:493-502. [PMID: 32556127 PMCID: PMC7545248 DOI: 10.1093/chemse/bjaa038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The chemical senses of taste and smell play a vital role in conveying information about ourselves and our environment. Tastes and smells can warn against danger and also contribute to the daily enjoyment of food, friends and family, and our surroundings. Over 12% of the US population is estimated to experience taste and smell (chemosensory) dysfunction. Yet, despite this high prevalence, long-term, effective treatments for these disorders have been largely elusive. Clinical successes in other sensory systems, including hearing and vision, have led to new hope for developments in the treatment of chemosensory disorders. To accelerate cures, we convened the "Identifying Treatments for Taste and Smell Disorders" conference, bringing together basic and translational sensory scientists, health care professionals, and patients to identify gaps in our current understanding of chemosensory dysfunction and next steps in a broad-based research strategy. Their suggestions for high-yield next steps were focused in 3 areas: increasing awareness and research capacity (e.g., patient advocacy), developing and enhancing clinical measures of taste and smell, and supporting new avenues of research into cellular and therapeutic approaches (e.g., developing human chemosensory cell lines, stem cells, and gene therapy approaches). These long-term strategies led to specific suggestions for immediate research priorities that focus on expanding our understanding of specific responses of chemosensory cells and developing valuable assays to identify and document cell development, regeneration, and function. Addressing these high-priority areas should accelerate the development of novel and effective treatments for taste and smell disorders.
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Affiliation(s)
| | - Linda A Barlow
- Department of Cell & Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Steven D Munger
- Center for Smell and Taste, Department of Pharmacology and Therapeutics, 1200 Newell Drive, University of Florida, Gainesville, FL, USA
| | - Sarah E Millar
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - M Natalia Vergara
- Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - James E Schwob
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, USA
| | - Bradley J Goldstein
- Department of Head and Neck Surgery and Communication Sciences, Duke University School of Medicine, 40 Duke Medicine Cir Clinic 1F, Durham, NC, USA
| | - Shannon E Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jeffrey R Martens
- Center for Smell and Taste, Department of Pharmacology and Therapeutics, 1200 Newell Drive, University of Florida, Gainesville, FL, USA
| | - Donald A Leopold
- Division of Otolaryngology Head and Neck Surgery, University of Vermont Medical Center, Burlington, VT, USA
| | - Linda M Bartoshuk
- Department of Food Science and Human Nutrition, Center for Smell and Taste, University of Florida, Gainesville, FL, USA
| | - Richard L Doty
- Smell and Taste Center and Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, 3400 Spruce Street, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas Hummel
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technische Universität Dresden, Fetscherstrasse, Dresden, Germany
| | - Jayant M Pinto
- Section of Otolaryngology—Head and Neck Surgery, Department of Surgery, The University of Chicago, MC, Chicago, IL, USA
| | | | | | - Edmund A Pribitkin
- Department of Otolaryngology—Head and Neck Surgery, Thomas Jefferson University, Philadelphia, PA, USA
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13
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Cleland TA, Borthakur A. A Systematic Framework for Olfactory Bulb Signal Transformations. Front Comput Neurosci 2020; 14:579143. [PMID: 33071767 PMCID: PMC7538604 DOI: 10.3389/fncom.2020.579143] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/17/2020] [Indexed: 11/13/2022] Open
Abstract
We describe an integrated theory of olfactory systems operation that incorporates experimental findings across scales, stages, and methods of analysis into a common framework. In particular, we consider the multiple stages of olfactory signal processing as a collective system, in which each stage samples selectively from its antecedents. We propose that, following the signal conditioning operations of the nasal epithelium and glomerular-layer circuitry, the plastic external plexiform layer of the olfactory bulb effects a process of category learning-the basis for extracting meaningful, quasi-discrete odor representations from the metric space of undifferentiated olfactory quality. Moreover, this early categorization process also resolves the foundational problem of how odors of interest can be recognized in the presence of strong competitive interference from simultaneously encountered background odorants. This problem is fundamentally constraining on early-stage olfactory encoding strategies and must be resolved if these strategies and their underlying mechanisms are to be understood. Multiscale general theories of olfactory systems operation are essential in order to leverage the analytical advantages of engineered approaches together with our expanding capacity to interrogate biological systems.
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Affiliation(s)
- Thomas A. Cleland
- Computational Physiology Laboratory, Department of Psychology, Cornell University, Ithaca, NY, United States
| | - Ayon Borthakur
- Computational Physiology Laboratory, Field of Computational Biology, Cornell University, Ithaca, NY, United States
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14
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Wang L, Zhang Z, Chen J, Manyande A, Haddad R, Liu Q, Xu F. Cell-Type-Specific Whole-Brain Direct Inputs to the Anterior and Posterior Piriform Cortex. Front Neural Circuits 2020; 14:4. [PMID: 32116571 PMCID: PMC7019026 DOI: 10.3389/fncir.2020.00004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/21/2020] [Indexed: 12/20/2022] Open
Abstract
The piriform cortex (PC) is a key brain area involved in both processing and coding of olfactory information. It is implicated in various brain disorders, such as epilepsy, Alzheimer’s disease, and autism. The PC consists of the anterior (APC) and posterior (PPC) parts, which are different anatomically and functionally. However, the direct input networks to specific neuronal populations within the APC and PPC remain poorly understood. Here, we mapped the whole-brain direct inputs to the two major neuronal populations, the excitatory glutamatergic principal neurons and inhibitory γ-aminobutyric acid (GABA)-ergic interneurons within the APC and PPC using the rabies virus (RV)-mediated retrograde trans-synaptic tracing system. We found that for both types of neurons, APC and PPC share some similarities in input networks, with dominant inputs originating from the olfactory region (OLF), followed by the cortical subplate (CTXsp), isocortex, cerebral nuclei (CNU), hippocampal formation (HPF) and interbrain (IB), whereas the midbrain (MB) and hindbrain (HB) were rarely labeled. However, APC and PPC also show distinct features in their input distribution patterns. For both types of neurons, the input proportion from the OLF to the APC was higher than that to the PPC; while the PPC received higher proportions of inputs from the HPF and CNU than the APC did. Overall, our results revealed the direct input networks of both excitatory and inhibitory neuronal populations of different PC subareas, providing a structural basis to analyze the diverse PC functions.
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Affiliation(s)
- Li Wang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,Center for Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Zhijian Zhang
- Center for Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Jiacheng Chen
- College of Life Sciences, Wuhan University, Wuhan, China
| | - Anne Manyande
- School of Human and Social Sciences, University of West London, Middlesex, United Kingdom
| | - Rafi Haddad
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Qing Liu
- Center for Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Fuqiang Xu
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,Center for Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.,University of the Chinese Academy of Sciences, Beijing, China.,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
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15
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Cheng H, Wang Y, Chen J, Chen Z. The piriform cortex in epilepsy: What we learn from the kindling model. Exp Neurol 2020; 324:113137. [DOI: 10.1016/j.expneurol.2019.113137] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022]
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16
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Task-Demand-Dependent Neural Representation of Odor Information in the Olfactory Bulb and Posterior Piriform Cortex. J Neurosci 2019; 39:10002-10018. [PMID: 31672791 DOI: 10.1523/jneurosci.1234-19.2019] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/16/2019] [Accepted: 10/19/2019] [Indexed: 02/03/2023] Open
Abstract
In awake rodents, the neural representation of olfactory information in the olfactory bulb is largely dependent on brain state and behavioral context. Learning-modified neural plasticity has been observed in mitral/tufted cells, the main output neurons of the olfactory bulb. Here, we propose that the odor information encoded by mitral/tufted cell responses in awake mice is highly dependent on the behavioral task demands. We used fiber photometry to record calcium signals from the mitral/tufted cell population in awake, head-fixed male mice under different task demands. We found that the mitral/tufted cell population showed similar responses to two distinct odors when the odors were presented in the context of a go/go task, in which the mice received a water reward regardless of the identity of the odor presented. However, when the same odors were presented in a go/no-go task, in which one odor was rewarded and the other was not, then the mitral cell population responded very differently to the two odors, characterized by a robust reduction in the response to the nonrewarded odor. Thus, the representation of odors in the mitral/tufted cell population depends on whether the task requires discrimination of the odors. Strikingly, downstream of the olfactory bulb, pyramidal neurons in the posterior piriform cortex also displayed a task-demand-dependent neural representation of odors, but the anterior piriform cortex did not, indicating that these two important higher olfactory centers use different strategies for neural representation.SIGNIFICANCE STATEMENT The most important task of the olfactory system is to generate a precise representation of odor information under different brain states. Whether the representation of odors by neurons in olfactory centers such as the olfactory bulb and the piriform cortex depends on task demands remains elusive. We find that odor representation in the mitral/tufted cells of the olfactory bulb depends on whether the task requires odor discrimination. A similar neural representation is found in the posterior piriform cortex but not the anterior piriform cortex, indicating that these higher olfactory centers use different representational strategies. The task-demand-dependent representational strategy is likely important for facilitating information processing in higher brain centers responsible for decision making and encoding of salience.
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17
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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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18
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Barron HC, Garvert MM, Behrens TEJ. Repetition suppression: a means to index neural representations using BOLD? Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0355. [PMID: 27574308 PMCID: PMC5003856 DOI: 10.1098/rstb.2015.0355] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2016] [Indexed: 01/10/2023] Open
Abstract
Understanding how the human brain gives rise to complex cognitive processes remains one of the biggest challenges of contemporary neuroscience. While invasive recording in animal models can provide insight into neural processes that are conserved across species, our understanding of cognition more broadly relies upon investigation of the human brain itself. There is therefore an imperative to establish non-invasive tools that allow human brain activity to be measured at high spatial and temporal resolution. In recent years, various attempts have been made to refine the coarse signal available in functional magnetic resonance imaging (fMRI), providing a means to investigate neural activity at the meso-scale, i.e. at the level of neural populations. The most widely used techniques include repetition suppression and multivariate pattern analysis. Human neuroscience can now use these techniques to investigate how representations are encoded across neural populations and transformed by relevant computations. Here, we review the physiological basis, applications and limitations of fMRI repetition suppression with a brief comparison to multivariate techniques. By doing so, we show how fMRI repetition suppression holds promise as a tool to reveal complex neural mechanisms that underlie human cognitive function. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’.
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Affiliation(s)
- Helen C Barron
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3TH, UK Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Mona M Garvert
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Timothy E J Behrens
- Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, UK
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