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Ekanayake A, Peiris S, Ahmed B, Kanekar S, Grove C, Kalra D, Eslinger P, Yang Q, Karunanayaka P. A Review of the Role of Estrogens in Olfaction, Sleep and Glymphatic Functionality in Relation to Sex Disparity in Alzheimer's Disease. Am J Alzheimers Dis Other Demen 2024; 39:15333175241272025. [PMID: 39116421 PMCID: PMC11311174 DOI: 10.1177/15333175241272025] [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] [Indexed: 08/10/2024]
Abstract
Several risk factors contribute to the development of Alzheimer's disease (AD), including genetics, metabolic health, cardiovascular history, and diet. It has been observed that women appear to face a higher risk of developing AD. Among the various hypotheses surrounding the gender disparity in AD, one pertains to the potential neuroprotective properties of estrogen. Compared to men, women are believed to be more susceptible to neuropathology due to the significant decline in circulating estrogen levels following menopause. Studies have shown, however, that estrogen replacement therapies in post-menopausal women do not consistently reduce the risk of AD. While menopause and estrogen levels are potential factors in the elevated incidence rates of AD among women, this review highlights the possible roles estrogen has in other pathways that may also contribute to the sex disparity observed in AD such as olfaction, sleep, and glymphatic functionality.
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Affiliation(s)
- Anupa Ekanayake
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
- Grodno State Medical University, Grodno, Belarus
| | - Senal Peiris
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
| | - Biyar Ahmed
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
| | - Sangam Kanekar
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
| | - Cooper Grove
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
| | - Deepak Kalra
- Department of Neurology, Penn State University College of Medicine, Hershey, PA, USA
| | - Paul Eslinger
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
- Department of Neurology, Penn State University College of Medicine, Hershey, PA, USA
| | - Qing Yang
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
- Department of Neurosurgery, Penn State University College of Medicine, Hershey, PA, USA
| | - Prasanna Karunanayaka
- Department of Radiology, Penn State University College of Medicine, Hershey, PA, USA
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2
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Strauch C, Hoang TH, Angenstein F, Manahan-Vaughan D. Olfactory Information Storage Engages Subcortical and Cortical Brain Regions That Support Valence Determination. Cereb Cortex 2021; 32:689-708. [PMID: 34379749 PMCID: PMC8841565 DOI: 10.1093/cercor/bhab226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 01/08/2023] Open
Abstract
The olfactory bulb (OB) delivers sensory information to the piriform cortex (PC) and other components of the olfactory system. OB-PC synapses have been reported to express short-lasting forms of synaptic plasticity, whereas long-term potentiation (LTP) of the anterior PC (aPC) occurs predominantly by activating inputs from the prefrontal cortex. This suggests that brain regions outside the olfactory system may contribute to olfactory information processing and storage. Here, we compared functional magnetic resonance imaging BOLD responses triggered during 20 or 100 Hz stimulation of the OB. We detected BOLD signal increases in the anterior olfactory nucleus (AON), PC and entorhinal cortex, nucleus accumbens, dorsal striatum, ventral diagonal band of Broca, prelimbic–infralimbic cortex (PrL-IL), dorsal medial prefrontal cortex, and basolateral amygdala. Significantly stronger BOLD responses occurred in the PrL-IL, PC, and AON during 100 Hz compared with 20 Hz OB stimulation. LTP in the aPC was concomitantly induced by 100 Hz stimulation. Furthermore, 100 Hz stimulation triggered significant nuclear immediate early gene expression in aPC, AON, and PrL-IL. The involvement of the PrL-IL in this process is consistent with its putative involvement in modulating behavioral responses to odor experience. Furthermore, these results indicate that OB-mediated information storage by the aPC is embedded in a connectome that supports valence evaluation.
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Affiliation(s)
- Christina Strauch
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
| | - Thu-Huong Hoang
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
| | - Frank Angenstein
- Functional Neuroimaging Group, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 39118 Magdeburg, Germany.,Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.,Medical Faculty, Otto-von Guericke University, 39118 Magdeburg, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
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Steiner AR, Rousseau-Blass F, Schroeter A, Hartnack S, Bettschart-Wolfensberger R. Systematic Review: Anesthetic Protocols and Management as Confounders in Rodent Blood Oxygen Level Dependent Functional Magnetic Resonance Imaging (BOLD fMRI)-Part B: Effects of Anesthetic Agents, Doses and Timing. Animals (Basel) 2021; 11:ani11010199. [PMID: 33467584 PMCID: PMC7830239 DOI: 10.3390/ani11010199] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary To understand brain function in rats and mice functional magnetic resonance imaging of the brain is used. With this type of “brain scan” regional changes in blood flow and oxygen consumption are measured as an indirect surrogate for activity of brain regions. Animals are often anesthetized for the experiments to prevent stress and blurred images due to movement. However, anesthesia may alter the measurements, as blood flow within the brain is differently affected by different anesthetics, and anesthetics also directly affect brain function. Consequently, results obtained under one anesthetic protocol may not be comparable with those obtained under another, and/or not representative for awake animals and humans. We have systematically searched the existing literature for studies analyzing the effects of different anesthesia methods or studies that compared anesthetized and awake animals. Most studies reported that anesthetic agents, doses and timing had an effect on functional magnetic resonance imaging results. To obtain results which promote our understanding of brain function, it is therefore essential that a standard for anesthetic protocols for functional magnetic resonance is defined and their impact is well characterized. Abstract In rodent models the use of functional magnetic resonance imaging (fMRI) under anesthesia is common. The anesthetic protocol might influence fMRI readouts either directly or via changes in physiological parameters. As long as those factors cannot be objectively quantified, the scientific validity of fMRI in rodents is impaired. In the present systematic review, literature analyzing in rats and mice the influence of anesthesia regimes and concurrent physiological functions on blood oxygen level dependent (BOLD) fMRI results was investigated. Studies from four databases that were searched were selected following pre-defined criteria. Two separate articles publish the results; the herewith presented article includes the analyses of 83 studies. Most studies found differences in BOLD fMRI readouts with different anesthesia drugs and dose rates, time points of imaging or when awake status was compared to anesthetized animals. To obtain scientifically valid, reproducible results from rodent fMRI studies, stable levels of anesthesia with agents suitable for the model under investigation as well as known and objectively quantifiable effects on readouts are, thus, mandatory. Further studies should establish dose ranges for standardized anesthetic protocols and determine time windows for imaging during which influence of anesthesia on readout is objectively quantifiable.
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Affiliation(s)
- Aline R. Steiner
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
- Correspondence:
| | - Frédérik Rousseau-Blass
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada;
| | - Aileen Schroeter
- Institute for Biomedical Engineering, University and ETH Zurich, 8093 Zurich, Switzerland;
| | - Sonja Hartnack
- Section of Epidemiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
| | - Regula Bettschart-Wolfensberger
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
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Zhurakovskaya E, Leikas J, Pirttimäki T, Casas Mon F, Gynther M, Aliev R, Rantamäki T, Tanila H, Forsberg MM, Gröhn O, Paasonen J, Jalkanen AJ. Sleep-State Dependent Alterations in Brain Functional Connectivity under Urethane Anesthesia in a Rat Model of Early-Stage Parkinson's Disease. eNeuro 2019; 6:ENEURO.0456-18.2019. [PMID: 30838323 PMCID: PMC6399428 DOI: 10.1523/eneuro.0456-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra, leading to striatal dopamine depletion. A partial unilateral striatal 6-hydroxydopamine (6-OHDA) lesion causes 40-60% dopamine depletion in the lesioned rat striatum, modeling the early stage of PD. In this study, we explored the connectivity between the brain regions in partially 6-OHDA lesioned male Wistar rats under urethane anesthesia using functional magnetic resonance imaging (fMRI) at 5 weeks after the 6-OHDA infusion. Under urethane anesthesia, the brain fluctuates between the two states, resembling rapid eye movement (REM) and non-REM sleep states. We observed clear urethane-induced sleep-like states in 8/19 lesioned animals and 8/18 control animals. 6-OHDA lesioned animals exhibited significantly lower functional connectivity between the brain regions. However, we observed these differences only during the REM-like sleep state, suggesting the involvement of the nigrostriatal dopaminergic pathway in REM sleep regulation. Corticocortical and corticostriatal connections were decreased in both hemispheres, reflecting the global effect of the lesion. Overall, this study describes a promising model to study PD-related sleep disorders in rats using fMRI.
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Affiliation(s)
- Ekaterina Zhurakovskaya
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Juuso Leikas
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Tiina Pirttimäki
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Francesc Casas Mon
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Mikko Gynther
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Rubin Aliev
- Moscow Institute of Physics and Technology, 117303, Moscow, Russia
- Institute of Theoretical and Experimental Biophysics, 142292, Puschino, Russia
| | - Tomi Rantamäki
- Laboratory of Neurotherapeutics, Division of Pharmacology and Pharmacotherapeutics, Faculty of Pharmacy, University of Helsinki, Helsinki, FI-00790, Finland
| | - Heikki Tanila
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Markus M. Forsberg
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Olli Gröhn
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Jaakko Paasonen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Aaro J. Jalkanen
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
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Paasonen J, Stenroos P, Salo RA, Kiviniemi V, Gröhn O. Functional connectivity under six anesthesia protocols and the awake condition in rat brain. Neuroimage 2018; 172:9-20. [DOI: 10.1016/j.neuroimage.2018.01.014] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/18/2017] [Accepted: 01/08/2018] [Indexed: 10/18/2022] Open
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Thompson GJ, Sanganahalli BG, Baker KL, Herman P, Shepherd GM, Verhagen JV, Hyder F. Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb. Neuroimage 2018; 172:586-596. [PMID: 29374582 DOI: 10.1016/j.neuroimage.2018.01.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/16/2018] [Accepted: 01/20/2018] [Indexed: 12/12/2022] Open
Abstract
Fluctuations in spontaneous activity have been observed by many neuroimaging techniques, but because these resting-state changes are not evoked by stimuli, it is difficult to determine how they relate to task-evoked activations. We conducted multi-modal neuroimaging scans of the rat olfactory bulb, both with and without odor, to examine interaction between spontaneous and evoked activities. Independent component analysis of spontaneous fluctuations revealed resting-state networks, and odor-evoked changes revealed activation maps. We constructed simulated activation maps using resting-state networks that were highly correlated to evoked activation maps. Simulated activation maps derived by intrinsic optical signal (IOS), which covers the dorsal portion of the glomerular sheet, significantly differentiated one odor's evoked activation map from the other two. To test the hypothesis that spontaneous activity of the entire glomerular sheet is relevant for representing odor-evoked activations, we used functional magnetic resonance imaging (fMRI) to map the entire glomerular sheet. In contrast to the IOS results, the fMRI-derived simulated activation maps significantly differentiated all three odors' evoked activation maps. Importantly, no evoked activation maps could be significantly differentiated using simulated activation maps produced using phase-randomized resting-state networks. Given that some highly organized resting-state networks did not correlate with any odors' evoked activation maps, we posit that these resting-state networks may characterize evoked activation maps associated with odors not studied. These results emphasize that fluctuations in spontaneous activity form a foundation for active processing, signifying the relevance of resting-state mapping to functional neuroimaging.
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Affiliation(s)
- Garth J Thompson
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Basavaraju G Sanganahalli
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA
| | - Keeley L Baker
- Department of Neuroscience, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT USA
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA
| | | | - Justus V Verhagen
- Department of Neuroscience, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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7
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Functional networks and network perturbations in rodents. Neuroimage 2017; 163:419-436. [DOI: 10.1016/j.neuroimage.2017.09.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 11/16/2022] Open
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8
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Guevara E, Pierre WC, Tessier C, Akakpo L, Londono I, Lesage F, Lodygensky GA. Altered Functional Connectivity Following an Inflammatory White Matter Injury in the Newborn Rat: A High Spatial and Temporal Resolution Intrinsic Optical Imaging Study. Front Neurosci 2017; 11:358. [PMID: 28725174 PMCID: PMC5495836 DOI: 10.3389/fnins.2017.00358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/08/2017] [Indexed: 12/05/2022] Open
Abstract
Very preterm newborns have an increased risk of developing an inflammatory cerebral white matter injury that may lead to severe neuro-cognitive impairment. In this study we performed functional connectivity (fc) analysis using resting-state optical imaging of intrinsic signals (rs-OIS) to assess the impact of inflammation on resting-state networks (RSN) in a pre-clinical model of perinatal inflammatory brain injury. Lipopolysaccharide (LPS) or saline injections were administered in postnatal day (P3) rat pups and optical imaging of intrinsic signals were obtained 3 weeks later. (rs-OIS) fc seed-based analysis including spatial extent were performed. A support vector machine (SVM) was then used to classify rat pups in two categories using fc measures and an artificial neural network (ANN) was implemented to predict lesion size from those same fc measures. A significant decrease in the spatial extent of fc statistical maps was observed in the injured group, across contrasts and seeds (*p = 0.0452 for HbO2 and **p = 0.0036 for HbR). Both machine learning techniques were applied successfully, yielding 92% accuracy in group classification and a significant correlation r = 0.9431 in fractional lesion volume prediction (**p = 0.0020). Our results suggest that fc is altered in the injured newborn brain, showing the long-standing effect of inflammation.
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Affiliation(s)
- Edgar Guevara
- Terahertz Science and Technology National Lab, CONACYT-Universidad Autónoma de San Luis Potosí, Coordinación para la Innovación y Aplicación de la Ciencia y la TecnologíaSan Luis Potosí, Mexico
| | - Wyston C Pierre
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Camille Tessier
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Luis Akakpo
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Irène Londono
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Frédéric Lesage
- Montreal Heart Institute, Research CenterMontreal, QC, Canada.,Department of Electrical Engineering, École Polytechnique de MontréalMontreal, QC, Canada
| | - Gregory A Lodygensky
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada.,Montreal Heart Institute, Research CenterMontreal, QC, Canada.,Department of Pharmacology, Université de MontréalMontreal, QC, Canada.,Department of Neuroscience, Université de MontréalMontreal, QC, Canada
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9
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Paasonen J, Salo RA, Huttunen JK, Gröhn O. Resting-state functional MRI as a tool for evaluating brain hemodynamic responsiveness to external stimuli in rats. Magn Reson Med 2016; 78:1136-1146. [PMID: 27774631 DOI: 10.1002/mrm.26496] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/06/2016] [Accepted: 09/14/2016] [Indexed: 11/11/2022]
Abstract
PURPOSE Anesthesia is a major confounding factor in functional MRI (fMRI) experiments attributed to its effects on brain function. Recent evidence suggests that parameters obtained with resting-state fMRI (rs-fMRI) are coupled with anesthetic depth. Therefore, we investigated whether parameters obtained with rs-fMRI, such as functional connectivity (FC), are also directly related to blood-oxygen-level-dependent (BOLD) responses. METHODS A simple rs-fMRI protocol was implemented in a pharmacological fMRI study to evaluate the coupling between hemodynamic responses and FC under five anesthetics (α-chloralose, isoflurane, medetomidine, thiobutabarbital, and urethane). Temporal change in the FC was evaluated at 1-hour interval. Supplementary forepaw stimulation experiments were also conducted. RESULTS Under thiobutabarbital anesthesia, FC was clearly coupled with nicotine-induced BOLD responses. Good correlation values were also obtained under isoflurane and medetomidine anesthesia. The observations in the thiobutabarbital group were supported by forepaw stimulation experiments. Additionally, the rs-fMRI protocol revealed significant temporal changes in the FC in the α-chloralose, thiobutabarbital, and urethane groups. CONCLUSION Our results suggest that FC can be used to estimate brain hemodynamic responsiveness to stimuli and evaluate the level and temporal changes of anesthesia. Therefore, analysis of the fMRI baseline signal may be highly valuable tool for controlling the outcome of preclinical fMRI experiments. Magn Reson Med 78:1136-1146, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jaakko Paasonen
- A.I.V. Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
| | - Raimo A Salo
- A.I.V. Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
| | - Joanna K Huttunen
- A.I.V. Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
| | - Olli Gröhn
- A.I.V. Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio, Finland
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10
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Courtiol E, Wilson DA. The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception. Perception 2016; 46:320-332. [PMID: 27687814 DOI: 10.1177/0301006616663216] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Olfactory perception and its underlying neural mechanisms are not fixed, but rather vary over time, dependent on various parameters such as state, task, or learning experience. In olfaction, one of the primary sensory areas beyond the olfactory bulb is the piriform cortex. Due to an increasing number of functions attributed to the piriform cortex, it has been argued to be an associative cortex rather than a simple primary sensory cortex. In fact, the piriform cortex plays a key role in creating olfactory percepts, helping to form configural odor objects from the molecular features extracted in the nose. Moreover, its dynamic interactions with other olfactory and nonolfactory areas are also critical in shaping the olfactory percept and resulting behavioral responses. In this brief review, we will describe the key role of the piriform cortex in the larger olfactory perceptual network, some of the many actors of this network, and the importance of the dynamic interactions among the piriform-trans-thalamic and limbic pathways.
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Affiliation(s)
- Emmanuelle Courtiol
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
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Global Functional Connectivity Differences between Sleep-Like States in Urethane Anesthetized Rats Measured by fMRI. PLoS One 2016; 11:e0155343. [PMID: 27168145 PMCID: PMC4863964 DOI: 10.1371/journal.pone.0155343] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/27/2016] [Indexed: 12/26/2022] Open
Abstract
Sleep is essential for nervous system functioning and sleep disorders are associated with several neurodegenerative diseases. However, the macroscale connectivity changes in brain networking during different sleep states are poorly understood. One of the hindering factors is the difficulty to combine functional connectivity investigation methods with spontaneously sleeping animals, which prevents the use of numerous preclinical animal models. Recent studies, however, have implicated that urethane anesthesia can uniquely induce different sleep-like brain states, resembling rapid eye movement (REM) and non-REM (NREM) sleep, in rodents. Therefore, the aim of this study was to assess changes in global connectivity and topology between sleep-like states in urethane anesthetized rats, using blood oxygenation level dependent (BOLD) functional magnetic resonance imaging. We detected significant changes in corticocortical (increased in NREM-like state) and corticothalamic connectivity (increased in REM-like state). Additionally, in graph analysis the modularity, the measure of functional integration in the brain, was higher in NREM-like state than in REM-like state, indicating a decrease in arousal level, as in normal sleep. The fMRI findings were supported by the supplementary electrophysiological measurements. Taken together, our results show that macroscale functional connectivity changes between sleep states can be detected robustly with resting-state fMRI in urethane anesthetized rats. Our findings pave the way for studies in animal models of neurodegenerative diseases where sleep abnormalities are often one of the first markers for the disorder development.
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12
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Persistent modification of forebrain networks and metabolism in rats following adolescent exposure to a 5-HT7 receptor agonist. Psychopharmacology (Berl) 2015; 232:75-89. [PMID: 24923983 DOI: 10.1007/s00213-014-3639-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE The serotonin 7 receptor (5-HT7-R) is part of a neuro-transmission system with a proposed role in neural plasticity and in mood, cognitive or sleep regulation. OBJECTIVES We investigated long-term consequences of sub-chronic treatment, during adolescence (43-45 to 47-49 days old) in rats, with a novel 5-HT7-R agonist (LP-211, 0 or 0.250 mg/kg/day). METHODS We evaluated behavioural changes as well as forebrain structural/functional modifications by in vivo magnetic resonance (MR) in a 4.7 T system, followed by ex vivo histology. RESULTS Adult rats pre-treated during adolescence showed reduced anxiety-related behaviour, in terms of reduced avoidance in the light/dark test and a less fragmented pattern of exploration in the novel object recognition test. Diffusion tensor imaging (DTI) revealed decreased mean diffusivity (MD) in the amygdala, increased fractional anisotropy (FA) in the hippocampus (Hip) and reduced axial (D||) together with increased radial (D⊥) diffusivity in the nucleus accumbens (NAcc). An increased neural dendritic arborization was confirmed in the NAcc by ex vivo histology. Seed-based functional MR imaging (fMRI) identified increased strength of connectivity within and between "limbic" and "cortical" loops, with affected cross-correlations between amygdala, NAcc and Hip. The latter displayed enhanced connections through the dorsal striatum (dStr) to dorso-lateral prefrontal cortex (dl-PFC) and cerebellum. Functional connection also increased between amygdala and limbic elements such as NAcc, orbito-frontal cortex (OFC) and hypothalamus. MR spectroscopy (1H-MRS) indicated that adolescent LP-211 exposure increased glutamate and total creatine in the adult Hip. CONCLUSIONS Persistent MR-detectable modifications indicate a rearrangement within forebrain networks, accounting for long-lasting behavioural changes as a function of developmental 5-HT7-R stimulation.
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Gong L, Li B, Wu R, Li A, Xu F. Brain-state dependent uncoupling of BOLD and local field potentials in laminar olfactory bulb. Neurosci Lett 2014; 580:1-6. [PMID: 25079901 DOI: 10.1016/j.neulet.2014.07.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/23/2014] [Accepted: 07/21/2014] [Indexed: 10/25/2022]
Abstract
The neural activities of the olfactory bulb (OB) can be modulated significantly by internal brain states. While blood oxygenation level dependent functional MRI (BOLD-fMRI) has been extensively applied to study OB in small animals, the relationship between BOLD signals and electrophysiological signals remains to be elucidated. Our recent study has revealed a complex relationship between BOLD and local field potentials (LFP) signals in different OB layers during odor stimulation. However, no study has been performed to compare these two types of signals under global brain states. Here, the changes of BOLD and LFP signals in the glomerular, mitral cell, and granular cell layers of the OB under different brain states, which were induced by different concentrations of isoflurane, were sequentially acquired using electrode array and high-resolution MRI. It was found that under deeper anesthesia, the LFP powers in all layers were decreased but the BOLD signals were unexpectedly increased. Furthermore, the decreases of LFP powers were layer-independent, but the increases of BOLD signal were layer-specific, with the order of glomerular>mitral cell>granular cell layer. The results provide new evidence that the direct neural activity levels might not be correlated well with BOLD signals in some cases, and remind us that cautions should be taken to use BOLD signals as the index of neural activities.
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Affiliation(s)
- Ling Gong
- Key Laboratory of Magnetic Resonance in Biological Systems and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo Li
- Key Laboratory of Magnetic Resonance in Biological Systems and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruiqi Wu
- Key Laboratory of Magnetic Resonance in Biological Systems and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Anan Li
- Key Laboratory of Magnetic Resonance in Biological Systems and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Fuqiang Xu
- Key Laboratory of Magnetic Resonance in Biological Systems and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; Wuhan National Laboratory for Optoelectronics, Wuhan 430074, China.
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14
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Meunier D, Fonlupt P, Saive AL, Plailly J, Ravel N, Royet JP. Modular structure of functional networks in olfactory memory. Neuroimage 2014; 95:264-75. [DOI: 10.1016/j.neuroimage.2014.03.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/25/2014] [Accepted: 03/15/2014] [Indexed: 01/01/2023] Open
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15
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Barnes DC, Wilson DA. Sleep and olfactory cortical plasticity. Front Behav Neurosci 2014; 8:134. [PMID: 24795585 PMCID: PMC4001050 DOI: 10.3389/fnbeh.2014.00134] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 04/03/2014] [Indexed: 12/21/2022] Open
Abstract
In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer's disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.
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Affiliation(s)
- Dylan C. Barnes
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric ResearchOrangeburg, NY, USA
- Behavioral and Cognitive Neuroscience Program, City University of New YorkNew York, NY, USA
- Department of Biology, University of OklahomaNorman, OK, USA
| | - Donald A. Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric ResearchOrangeburg, NY, USA
- Behavioral and Cognitive Neuroscience Program, City University of New YorkNew York, NY, USA
- Department of Biology, University of OklahomaNorman, OK, USA
- Department of Child and Adolescent Psychiatry, New York University Langone School of MedicineNew York, NY, USA
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16
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Carlson KS, Dillione MR, Wesson DW. Odor- and state-dependent olfactory tubercle local field potential dynamics in awake rats. J Neurophysiol 2014; 111:2109-23. [PMID: 24598519 DOI: 10.1152/jn.00829.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The olfactory tubercle (OT), a trilaminar structure located in the basal forebrain of mammals, is thought to play an important role in olfaction. While evidence has accumulated regarding the contributions of the OT to odor information processing, studies exploring the role of the OT in olfaction in awake animals remain unavailable. In the present study, we begin to address this void through multiday recordings of local field potential (LFP) activity within the OT of awake, freely exploring Long-Evans rats. We observed spontaneous OT LFP activity consisting of theta- (2-12 Hz), beta- (15-35 Hz) and gamma- (40-80 Hz) band activity, characteristic of previous reports of LFPs in other principle olfactory structures. Beta- and gamma-band powers were enhanced upon odor presentation. Simultaneous recordings of OT and upstream olfactory bulb (OB) LFPs revealed odor-evoked LFP power at statistically similar levels in both structures. Strong spectral coherence was observed between the OT and OB during both spontaneous and odor-evoked states. Furthermore, the OB theta rhythm more strongly cohered with the respiratory rhythm, and respiratory-coupled theta cycles in the OT occurred following theta cycles in the OB. Finally, we found that the animal's internal state modulated LFP activity in the OT. Together, these data provide initial insights into the network activity of the OT in the awake rat, including spontaneous rhythmicity, odor-evoked modulation, connectivity with upstream sensory input, and state-dependent modulation.
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Affiliation(s)
- Kaitlin S Carlson
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Maggie R Dillione
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Daniel W Wesson
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and Department of Biology, Case Western Reserve University, Cleveland, Ohio
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17
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Abstract
The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer's disease, Parkinson's disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity?
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18
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Shanahan LK, Gottfried JA. Olfactory Insights into Sleep-Dependent Learning and Memory. PROGRESS IN BRAIN RESEARCH 2014; 208:309-43. [DOI: 10.1016/b978-0-444-63350-7.00012-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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Jonckers E, Delgado y Palacios R, Shah D, Guglielmetti C, Verhoye M, Van der Linden A. Different anesthesia regimes modulate the functional connectivity outcome in mice. Magn Reson Med 2013; 72:1103-12. [DOI: 10.1002/mrm.24990] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 09/13/2013] [Accepted: 09/16/2013] [Indexed: 01/09/2023]
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20
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Breathing and brain state: Urethane anesthesia as a model for natural sleep. Respir Physiol Neurobiol 2013; 188:324-32. [DOI: 10.1016/j.resp.2013.05.035] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/06/2013] [Accepted: 05/28/2013] [Indexed: 01/26/2023]
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21
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Lang J, Li A, Luo W, Wu R, Li P, Xu F. Odor representation in the olfactory bulb under different brain states revealed by intrinsic optical signals imaging. Neuroscience 2013; 243:54-63. [PMID: 23567814 DOI: 10.1016/j.neuroscience.2013.03.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 03/17/2013] [Accepted: 03/23/2013] [Indexed: 10/27/2022]
Abstract
The olfactory system responds to the same stimulus with great variability according to the current state of the brain. At the levels of multi-unit activity and local field potentials, the response of the olfactory bulb (OB) to a given olfactory stimulus during a state of lower background activity is stronger than the response that occurs during higher background activity, but the distribution pattern of activity remains similar. However, these results have only been established at the individual neuron and neuron cluster scales in previous studies. It remains unclear whether these results are consistent at a larger scale (e.g., OB regions); therefore, intrinsic optical signals imaging was employed in the present study to clarify this issue. The basal brain states of rats were manipulated by using different levels of anesthesia. Under a state of low basal brain activity, the intensity of the activity pattern elicited in the dorsal OB by a given odorant was significantly higher than that under high basal brain activity, but the topography was highly similar across different brain states. These results were consistent across the levels of individual neurons, neuron clusters, glomeruli, and the OB regions, which suggest that the OB contains as yet unknown neural mechanisms that ensure the high-fidelity representation of the same olfactory stimulation under different brain states.
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Affiliation(s)
- J Lang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
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22
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Connectivity of the amygdala, piriform, and orbitofrontal cortex during olfactory stimulation. Neuroreport 2013; 24:171-5. [DOI: 10.1097/wnr.0b013e32835d5d2b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Guilfoyle DN, Gerum SV, Sanchez JL, Balla A, Sershen H, Javitt DC, Hoptman MJ. Functional connectivity fMRI in mouse brain at 7T using isoflurane. J Neurosci Methods 2013; 214:144-8. [PMID: 23376497 DOI: 10.1016/j.jneumeth.2013.01.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/16/2013] [Accepted: 01/18/2013] [Indexed: 02/03/2023]
Abstract
Although many resting state fMRI human studies have been published, the number of such rodent studies is considerably less. The reason for this is the severe technical challenge of high magnetic field small rodent imaging. Local magnetic field susceptibility changes at air tissue boundaries cause image distortion and signal losses. The current study reports measures of functional connectivity in mice using only isoflurane for the anesthetic. Because all anesthetic agents will alter cerebral blood flow and cerebral metabolism, the impact these changes have on neuronal connectivity has yet to be fully understood, however this work reports for the first time that reliable functional connectivity measures in mouse brain can be obtained with isoflurane.
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Affiliation(s)
- David N Guilfoyle
- Center for Advanced Brain Imaging, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
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24
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Arzi A, Shedlesky L, Ben-Shaul M, Nasser K, Oksenberg A, Hairston IS, Sobel N. Humans can learn new information during sleep. Nat Neurosci 2012; 15:1460-5. [PMID: 22922782 DOI: 10.1038/nn.3193] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/27/2012] [Indexed: 02/06/2023]
Abstract
During sleep, humans can strengthen previously acquired memories, but whether they can acquire entirely new information remains unknown. The nonverbal nature of the olfactory sniff response, in which pleasant odors drive stronger sniffs and unpleasant odors drive weaker sniffs, allowed us to test learning in humans during sleep. Using partial-reinforcement trace conditioning, we paired pleasant and unpleasant odors with different tones during sleep and then measured the sniff response to tones alone during the same nights' sleep and during ensuing wake. We found that sleeping subjects learned novel associations between tones and odors such that they then sniffed in response to tones alone. Moreover, these newly learned tone-induced sniffs differed according to the odor pleasantness that was previously associated with the tone during sleep. This acquired behavior persisted throughout the night and into ensuing wake, without later awareness of the learning process. Thus, humans learned new information during sleep.
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Affiliation(s)
- Anat Arzi
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
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25
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Abstract
Natural odors, generally composed of many monomolecular components, are analyzed by peripheral receptors into component features and translated into spatiotemporal patterns of neural activity in the olfactory bulb. Here, we will discuss the role of the olfactory cortex in the recognition, separation and completion of those odor-evoked patterns, and how these processes contribute to odor perception. Recent findings regarding the neural architecture, physiology, and plasticity of the olfactory cortex, principally the piriform cortex, will be described in the context of how this paleocortical structure creates odor objects.
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Affiliation(s)
- Donald A Wilson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
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