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Brunert D, Quintela RM, Rothermel M. The anterior olfactory nucleus revisited - an emerging role for neuropathological conditions? Prog Neurobiol 2023:102486. [PMID: 37343762 DOI: 10.1016/j.pneurobio.2023.102486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
Olfaction is an important sensory modality for many species and greatly influences animal and human behavior. Still, much about olfactory perception remains unknown. The anterior olfactory nucleus is one of the brain's central early olfactory processing areas. Located directly posterior to the olfactory bulb in the olfactory peduncle with extensive in- and output connections and unique cellular composition, it connects olfactory processing centers of the left and right hemispheres. Almost 20 years have passed since the last comprehensive review on the anterior olfactory nucleus has been published and significant advances regarding its anatomy, function, and pathophysiology have been made in the meantime. Here we briefly summarize previous knowledge on the anterior olfactory nucleus, give detailed insights into the progress that has been made in recent years, and map out its emerging importance in translational research of neurological diseases.
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Affiliation(s)
- Daniela Brunert
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | | | - Markus Rothermel
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany.
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2
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Murray HC, Saar G, Bai L, Bouraoud N, Dodd S, Highet B, Ryan B, Curtis MA, Koretsky A, Belluscio L. Progressive Spread of Beta-amyloid Pathology in an Olfactory-driven Amyloid Precursor Protein Mouse Model. Neuroscience 2023; 516:113-124. [PMID: 36716914 PMCID: PMC10065898 DOI: 10.1016/j.neuroscience.2023.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/04/2022] [Accepted: 01/13/2023] [Indexed: 01/29/2023]
Abstract
Years before Alzheimer's disease (AD) is diagnosed, patients experience an impaired sense of smell, and β-amyloid plaques accumulate within the olfactory mucosa and olfactory bulb (OB). The olfactory vector hypothesis proposes that external agents cause β-amyloid to aggregate and spread from the OB to connected downstream brain regions. To reproduce the slow accumulation of β-amyloid that occurs in human AD, we investigated the progressive accumulation of β-amyloid across the brain using a conditional mouse model that overexpresses a humanized mutant form of the amyloid precursor protein (hAPP) in olfactory sensory neurons. Using design-based stereology, we show the progressive accumulation of β-amyloid plaques within the OB and cortical olfactory regions with age. We also observe reduced OB volumes in these mice when hAPP expression begins prior-to but not post-weaning which we tracked using manganese-enhanced MRI. We therefore conclude that the reduced OB volume does not represent progressive degeneration but rather disrupted OB development. Overall, our data demonstrate that hAPP expression in the olfactory epithelium can lead to the accumulation and spread of β-amyloid through the olfactory system into the hippocampus, consistent with an olfactory system role in the early stages of β-amyloid-related AD progression.
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Affiliation(s)
- Helen C Murray
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland 1023, New Zealand; Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Galit Saar
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Li Bai
- Circuits, Synapses and Molecular Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Nadia Bouraoud
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Stephen Dodd
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Blake Highet
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland 1023, New Zealand.
| | - Brigid Ryan
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland 1023, New Zealand.
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland 1023, New Zealand.
| | - Alan Koretsky
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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3
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Hook C, Puche AC. Bulbar projecting subcortical GABAergic neurons send collateral branches extensively and selectively to primary olfactory cortical regions. J Comp Neurol 2023; 531:451-460. [PMID: 36463397 PMCID: PMC9795336 DOI: 10.1002/cne.25434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/26/2022] [Accepted: 10/27/2022] [Indexed: 12/05/2022]
Abstract
Circuit operations of the olfactory bulb are modulated by higher order projections from multiple regions, many of which are themselves targets of bulbar output. Multiple glutamatergic regions project to the olfactory bulb, including the anterior olfactory nucleus (AON), prefrontal cortex (PFC), piriform cortex (PC), entorhinal cortex (EC), and tenia tecta (TT). In contrast, only one region provides GABAergic projections to the bulb. These GABA neurons are located in the horizontal limb of the diagonal band of Broca extending posteriorly through the magnocellular preoptic nucleus to the nucleus of the lateral olfactory bulb. However, it was unclear whether bulbar projecting GABAergic neurons collaterallize projecting to other brain regions. To address this, we mapped collateral projections from bulbar projecting GABAergic neurons using intersectional strategies of viral and traditional tract tracers. This approach revealed bulbar projecting GABAergic neurons show remarkable specificity targeting other primary olfactory cortical regions exhibiting abundant collateral projections into the accessory olfactory bulb, AON, PFC, PC, and TT. The only "nonolfactory" region receiving collateral projections was sparse connectivity to the medial prefrontal orbital cortex. This suggests that basal forebrain inhibitory feedback also modulates glutamatergic feedback areas that are themselves prominent bulbar projection regions. Thus, inhibitory feedback may be simultaneously modulating both synaptic processing of olfactory information in the bulb and associational processing of olfactory information from primary olfactory cortex. We hypothesize that these olfactory GABAergic feedback neurons are a regulator of the entire olfactory system.
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Affiliation(s)
- Chelsea Hook
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Adam C Puche
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Chae H, Banerjee A, Dussauze M, Albeanu DF. Long-range functional loops in the mouse olfactory system and their roles in computing odor identity. Neuron 2022; 110:3970-3985.e7. [PMID: 36174573 PMCID: PMC9742324 DOI: 10.1016/j.neuron.2022.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 07/12/2022] [Accepted: 09/02/2022] [Indexed: 12/15/2022]
Abstract
Elucidating the neural circuits supporting odor identification remains an open challenge. Here, we analyze the contribution of the two output cell types of the mouse olfactory bulb (mitral and tufted cells) to decode odor identity and concentration and its dependence on top-down feedback from their respective major cortical targets: piriform cortex versus anterior olfactory nucleus. We find that tufted cells substantially outperform mitral cells in decoding both odor identity and intensity. Cortical feedback selectively regulates the activity of its dominant bulb projection cell type and implements different computations. Piriform feedback specifically restructures mitral responses, whereas feedback from the anterior olfactory nucleus preferentially controls the gain of tufted representations without altering their odor tuning. Our results identify distinct functional loops involving the mitral and tufted cells and their cortical targets. We suggest that in addition to the canonical mitral-to-piriform pathway, tufted cells and their target regions are ideally positioned to compute odor identity.
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Affiliation(s)
- Honggoo Chae
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Arkarup Banerjee
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Cold Spring Harbor Laboratory School for Biological Sciences, Cold Spring Harbor, NY, USA
| | - Marie Dussauze
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Cold Spring Harbor Laboratory School for Biological Sciences, Cold Spring Harbor, NY, USA
| | - Dinu F Albeanu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Cold Spring Harbor Laboratory School for Biological Sciences, Cold Spring Harbor, NY, USA.
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5
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Brunjes PC. Pyramidal Cells in Olfactory Cortex. Chem Senses 2021; 46:6089162. [PMID: 33433589 DOI: 10.1093/chemse/bjab002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The neocortex and olfactory cortices share many features including their laminar organization, developmental sequences, and cell types. Previous work indicates that neocortical pyramidal cells exhibit a gradient of dendritic size: cells involved in the initial processing of information are less complex than those in subsequent, higher processing areas. Results presented here confirm that the same is true for the olfactory cortex: pyramidal cells in the region closest to the olfactory bulb, the anterior olfactory nucleus, have smaller total dendritic length and occupy less neural space than those in the posterior piriform cortex. These findings add to the evidence for general rules of development, organization, and function across forebrain cortices.
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Affiliation(s)
- Peter C Brunjes
- Department Psychology, University of Virginia, Charlottesville, VA 22904, USA
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6
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Russo MJ, Franks KM, Oghaz R, Axel R, Siegelbaum SA. Synaptic Organization of Anterior Olfactory Nucleus Inputs to Piriform Cortex. J Neurosci 2020; 40:9414-25. [PMID: 33115926 DOI: 10.1523/JNEUROSCI.0965-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 11/21/2022] Open
Abstract
Odors activate distributed ensembles of neurons within the piriform cortex, forming cortical representations of odor thought to be essential to olfactory learning and behaviors. This odor response is driven by direct input from the olfactory bulb, but is also shaped by a dense network of associative or intracortical inputs to piriform, which may enhance or constrain the cortical odor representation. With optogenetic techniques, it is possible to functionally isolate defined inputs to piriform cortex and assess their potential to activate or inhibit piriform pyramidal neurons. The anterior olfactory nucleus (AON) receives direct input from the olfactory bulb and sends an associative projection to piriform cortex that has potential roles in the state-dependent processing of olfactory behaviors. Here, we provide a detailed functional assessment of the AON afferents to piriform in male and female C57Bl/6J mice. We confirm that the AON forms glutamatergic excitatory synapses onto piriform pyramidal neurons; and while these inputs are not as strong as piriform recurrent collaterals, they are less constrained by disynaptic inhibition. Moreover, AON-to-piriform synapses contain a substantial NMDAR-mediated current that prolongs the synaptic response at depolarized potentials. These properties of limited inhibition and slow NMDAR-mediated currents result in strong temporal summation of AON inputs within piriform pyramidal neurons, and suggest that the AON could powerfully enhance activation of piriform neurons in response to odor.SIGNIFICANCE STATEMENT Odor information is transmitted from olfactory receptors to olfactory bulb, and then to piriform cortex, where ensembles of activated neurons form neural representations of the odor. While these ensembles are driven by primary bulbar afferents, and shaped by intracortical recurrent connections, the potential for another early olfactory area, the anterior olfactory nucleus (AON), to contribute to piriform activity is not known. Here, we use optogenetic circuit-mapping methods to demonstrate that AON inputs can significantly activate piriform neurons, as they are coupled to NMDAR currents and to relatively modest disynaptic inhibition. The AON may enhance the piriform odor response, encouraging further study to determine the states or behaviors through which AON potentiates the cortical response to odor.
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Abstract
The tenia tecta is extensively interconnected with the main olfactory bulb and olfactory cortical areas and is well positioned to contribute to olfactory processing. However, little is known about odor representation within its dorsal (DTT) and ventral (VTT) components. To address this need, spontaneous and odor-evoked activity of DTT and VTT neurons was recorded from urethane anesthetized mice and compared to activity recorded from adjacent areas within adjacent caudomedial aspects of the anterior olfactory nucleus (AON). Neurons recorded from DTT, VTT, and AON exhibited odor-selective alterations in firing rate in response to a diverse set of monomolecular odorants. While DTT and AON neurons exhibited similar tuning breadth, selectivity, and response topography, the proportion of odor-selective neurons was substantially higher in the DTT. These findings provide evidence that the tenia tecta may contribute to the encoding of specific stimulus attributes. Further work is needed to fully characterize functional organization of the tenia tecta and its contribution to sensory representation and utilization.
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Key Words
- AON, Anterior olfactory nucleus
- CV, Coefficient of variation
- CoA, Cortical amygdala
- DPC, Dorsal peduncular cortex
- DTT, Dorsal tenia tecta
- EC, Entorhinal cortex
- ISI, Interspike interval
- OB, Main olfactory bulb
- OT, Olfactory tubercle
- Olfaction
- PC, Piriform cortex
- TT, Tenia tecta
- VTT, Ventral tenia tecta
- anterior olfactory nucleus
- olfactory peduncle
- sensory tuning
- tenia tecta
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Affiliation(s)
- Graham A. Cousens
- Department of Psychology and Neuroscience Program, Drew University, 36 Madison Avenue, Madison, NJ, 07940, USA
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Nakahara TS, Carvalho VMA, Papes F. From Synapse to Supper: A Food Preference Recipe with Olfactory Synaptic Ingredients. Neuron 2020; 107:8-11. [PMID: 32645309 DOI: 10.1016/j.neuron.2020.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
C1ql3 protein and its receptor Bai3 are involved in synaptic organization and function. In this issue of Neuron, Wang et al. (2020) report that both are essential for synaptic function between the anterior olfactory nucleus and the olfactory bulb and for the generation, but not recall, of associative olfactory memories determining food preference in mice.
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Affiliation(s)
- Thiago S Nakahara
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas, Rua Monteiro Lobato, s/n, Campinas, Sao Paulo 13083-862, Brazil; Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Av. Prof. Lineu Prestes, 748, Sao Paulo 05508-000, Brazil
| | - Vinicius M A Carvalho
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas, Rua Monteiro Lobato, s/n, Campinas, Sao Paulo 13083-862, Brazil
| | - Fabio Papes
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas, Rua Monteiro Lobato, s/n, Campinas, Sao Paulo 13083-862, Brazil.
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Highet B, Dieriks BV, Murray HC, Faull RLM, Curtis MA. Huntingtin Aggregates in the Olfactory Bulb in Huntington's Disease. Front Aging Neurosci 2020; 12:261. [PMID: 33013352 PMCID: PMC7461834 DOI: 10.3389/fnagi.2020.00261] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/31/2020] [Indexed: 12/03/2022] Open
Abstract
Olfactory deficits are an early and prevalent non-motor symptom of Huntington's disease (HD). In other neurodegenerative diseases where olfactory deficits occur, such as Alzheimer's disease and Parkinson's disease, pathological protein aggregates (tau, β-amyloid, α-synuclein) accumulate in the anterior olfactory nucleus (AON) of the olfactory bulb (OFB). Therefore, in this study we determined whether aggregates are also present in HD OFBs; 13 HD and five normal human OFBs were stained for mutant huntingtin (mHtt), tau, β-amyloid, TDP-43, and α-synuclein. Our results show that mHtt aggregates detected with 1F8 antibody are present within all HD OFBs, and mHtt aggregate load in the OFB does not correlate with Vonsattel grading scores. The majority of the aggregates were located in the AON and in similar abundance in each anatomical segment of the AON. No mHtt aggregates were found in controls; 31% of HD cases also contained tau neurofibrillary tangles within the AON. This work demonstrates HD pathology in the OFB and indicates that disease-specific protein aggregation in the AON is a common feature of neurodegenerative diseases that show olfactory deficits.
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Affiliation(s)
- Blake Highet
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Birger Victor Dieriks
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Helen C. Murray
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Richard L. M. Faull
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
| | - Maurice A. Curtis
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, The University of Auckland, Auckland, New Zealand
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Wang CY, Liu Z, Ng YH, Südhof TC. A Synaptic Circuit Required for Acquisition but Not Recall of Social Transmission of Food Preference. Neuron 2020; 107:144-157.e4. [PMID: 32369733 PMCID: PMC7351611 DOI: 10.1016/j.neuron.2020.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 01/24/2020] [Accepted: 03/31/2020] [Indexed: 12/20/2022]
Abstract
During social transmission of food preference (STFP), the combination of an olfactory sensory input with a social cue induces long-term memory of a food odor. How a social cue produces long-term learning of an olfactory input, however, remains unknown. Here we show that the neurons of the anterior olfactory nucleus (AON), which form abundant synaptic projections onto granule cells in the olfactory bulb (OB), express the synaptogenic molecule C1ql3. Deletion of C1ql3 in the dorsolateral AON impaired synaptic AON→OB connections and abolished acquisition, but not recall, of STFP memory without significantly affecting basal olfaction. Moreover, deletion in granule cells of the OB of Bai3, a postsynaptic GPCR that binds C1ql3, similarly suppressed synaptic transmission at AON→OB projections and abolished acquisition, but not recall, of STFP memory. Thus, synaptic AON→OB connections are selectively required for STFP memory acquisition and are formed by an essential interaction of presynaptic C1ql3 with postsynaptic Bai3.
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Affiliation(s)
- Cosmos Yuqi Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Zhihui Liu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yi Han Ng
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Collins LN, Brunjes PC. The mouse olfactory peduncle 4: Development of synapses, perineuronal nets, and capillaries. J Comp Neurol 2020; 528:637-649. [PMID: 31571216 PMCID: PMC6944759 DOI: 10.1002/cne.24778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 11/09/2022]
Abstract
Olfaction is critical for survival in neonatal mammals. However, little is known about the neural substrate for this ability as few studies of synaptic development in several olfactory processing regions have been reported. Odor information detected in the nasal cavity is first processed by the olfactory bulb and then sent via the lateral olfactory tract to a series of olfactory cortical areas. The first of these, the anterior olfactory nucleus pars principalis (AONpP), is a simple, two layered cortex with an outer plexiform and inner cell zone (Layers 1 and 2, respectively). Five sets of studies examined age-related changes in the AONpP. First, immunocytochemistry for glutamatergic (VGlut1 and VGlut2) and GABAergic (VGAT) synapses demonstrated that overall synaptic patterns remained uniform with age. The second set quantified synaptic development with electron microscopy and found different developmental patterns between Layers 1 and 2. As many of the interhemispheric connections in the olfactory system arise from AONpP, the third set examined the development of crossed projections using anterograde tracers and electron microscopy to explore the maturation of this pathway. A fourth study examined ontogenetic changes in immunostaining for the proteoglycans aggrecan and brevican, markers of mesh-like extracellular structures known as perineuronal nets whose maturation is associated with the end of early critical periods of synaptogenesis. A final study found no age-related changes in the density of vasculature in the peduncle from P5 to P30. This work is among the first to examine early postnatal changes in this initial cortical region of the olfactory system.
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Affiliation(s)
- Lindsay N. Collins
- Department Psychology, University of Virginia, Charlottesville, Virginia 22904 USA
| | - Peter C. Brunjes
- Department Psychology, University of Virginia, Charlottesville, Virginia 22904 USA
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12
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Saiz-Sanchez D, Ubeda-Bañon I, Flores-Cuadrado A, Gonzalez-Rodriguez M, Villar-Conde S, Astillero-Lopez V, Martinez-Marcos A. Somatostatin, Olfaction, and Neurodegeneration. Front Neurosci 2020; 14:96. [PMID: 32140092 PMCID: PMC7042373 DOI: 10.3389/fnins.2020.00096] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's and Parkinson's diseases are the most prevalent neurodegenerative disorders in aging. Hyposmia has been described as an early symptom that can precede cognitive and motor deficits by decades. Certain regions within the olfactory system, such as the anterior olfactory nucleus, display the neuropathological markers tau and amyloid-β or α-synuclein from the earliest stages of disease progression in a preferential manner. Specific neuronal subpopulations, namely those expressing somatostatin (SST), are preferentially affected throughout the olfactory and limbic systems. SST is a neuropeptide present in a subpopulation of GABAergic interneurons throughout the brain and its main function is to inhibit principal neurons and/or other interneurons. It has been reported that SST expression is reduced by 50% in Alzheimer's disease and that it is related to the formation of Aβ oligomers. The mechanisms underlying the preferential vulnerability of SST-expressing neurons in Alzheimer's disease (and, to a minor extent, in Parkinson's disease) are not known but analysis of the available data could shed light on their etiology. This short review aims to update the knowledge of functional features of somatostatin within the olfactory system and its role in olfactory deficits during neurodegeneration.
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Affiliation(s)
- Daniel Saiz-Sanchez
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Isabel Ubeda-Bañon
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Alicia Flores-Cuadrado
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Melania Gonzalez-Rodriguez
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Sandra Villar-Conde
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Veronica Astillero-Lopez
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Alino Martinez-Marcos
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha, Ciudad Real, Spain
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13
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Abstract
Odorant molecules stimulate olfactory receptor neurons, and axons of these neurons project into the main olfactory bulb where they synapse onto mitral and tufted cells. These project to the primary olfactory cortex including the anterior olfactory nucleus (AON), the piriform cortex, amygdala, and the entorhinal cortex. The properties of mitral cells have been investigated extensively, but how odor information is processed in subsequent brain regions is less well known. In the present study, we recorded the electrical activity of AON neurons in anesthetized rats. Most AON cells fired in bursts of 2-10 spikes separated by very short intervals (<20 ms), in a period linked to the respiratory rhythm. Simultaneous recordings from adjacent neurons revealed that the rhythms of adjacent cells, while locked to the same underlying rhythm, showed marked differences in phase. We studied the responses of AON cells to brief high-frequency stimulation of the lateral olfactory tract, mimicking brief activation of mitral cells by odor. In different cells, such stimuli evoked transient or sustained bursts during stimulation or, more commonly, post-stimulation bursts after inhibition during stimulation. This suggests that, in AON cells, phase shifts occur as a result of post-inhibitory rebound firing, following inhibition by mitral cell input, and we discuss how this supports processing of odor information in the olfactory pathway. Cells were tested for their responsiveness to a social odor (the bedding of a strange male) among other simple and complex odors tested. In total, 11 cells responded strongly and repeatedly to bedding odor, and these responses were diverse, including excitation (transient or sustained), inhibition, and activation after odor presentation, indicating that AON neurons respond not only to the type of complex odor but also to temporal features of odor application.
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Affiliation(s)
- Takahiro Tsuji
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
| | - Chiharu Tsuji
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
| | - Maja Lozic
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
| | - Mike Ludwig
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
- Department of ImmunologyCentre for NeuroendocrinologyUniversity of PretoriaPretoriaSouth Africa
| | - Gareth Leng
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
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Linster C, Kelsch W. A Computational Model of Oxytocin Modulation of Olfactory Recognition Memory. eNeuro 2019; 6:ENEURO. [PMID: 31399493 DOI: 10.1523/ENEURO.0201-19.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/14/2019] [Accepted: 07/31/2019] [Indexed: 11/21/2022] Open
Abstract
Social recognition in mammals depends on complex interactions between sensory and other brain areas as well as modulatory inputs by specific neuropeptides such as oxytocin (OXT). Social recognition memory specifically has been shown to depend among others on olfactory processing, and can be probed using methods similar to those used when probing non-social odor memory. We here use a computational model of two interconnected olfactory networks in the mouse, the olfactory bulb (OB) and anterior olfactory nucleus, to propose a mechanism for olfactory short-term recognition memory and its modulation in social situations. Based on previous experiments, we propose one early locus for memory to be the OB. During social encounters in mice, pyramidal cells in the anterior olfactory nucleus, themselves driven by olfactory input, are rendered more excitable by OXT release, resulting in stronger feedback to OB local interneurons. This additional input to the OB creates stronger dynamics and improves signal-to-noise ratio of odor responses in the OB proper. As a consequence, mouse social olfactory memories are more strongly encoded and their duration is modulated.
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15
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Kasanuki K, Ross OA, DeTure MA, Walton RL, Sanchez-Contreras M, Koga S, Murray ME, Rademakers R, Dickson DW. Relationships between lewy and tau pathologies in 375 consecutive non-Alzheimer's olfactory bulbs. Mov Disord 2018; 33:333-334. [PMID: 29322556 DOI: 10.1002/mds.27250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/13/2017] [Accepted: 10/30/2017] [Indexed: 11/08/2022] Open
Affiliation(s)
- Koji Kasanuki
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Owen A Ross
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Michael A DeTure
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Ronald L Walton
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | | | - Shunsuke Koga
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Melissa E Murray
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
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16
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Tsuji C, Tsuji T, Allchorne A, Leng G, Ludwig M. Effects of lateral olfactory tract stimulation on Fos immunoreactivity in vasopressin neurones of the rat piriform cortex. J Neuroendocrinol 2017; 29:e12531. [PMID: 28862781 DOI: 10.1111/jne.12531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 11/28/2022]
Abstract
In the main olfactory system, odours are registered at the main olfactory epithelium and are then processed at the main olfactory bulb (MOB) and, subsequently, by the anterior olfactory nucleus (AON), the piriform cortex (PC) and the cortical amygdala. Previously, we reported populations of vasopressin neurones in different areas of the rat olfactory system, including the MOB, accessory olfactory bulb (AOB) and the AON and showed that these are involved in the coding of social odour information. Utilising immunohistochemistry and a transgenic rat in which an enhanced green fluorescent protein reporter gene is expressed in vasopressin neurones (eGFP-vasopressin), we now show a population of vasopressin neurones in the PC. The vasopressin neurones are predominantly located in the layer II of the PC and the majority co-express the excitatory transmitter glutamate. Furthermore, there is no sex difference in the number of neurones expressing vasopressin. Electrical stimulation of the lateral olfactory tract leads to a significant increase in the number of Fos-positive nuclei in the PC, MOB, AOB, dorsal AON and supraoptic nucleus (SON). However, there was only a significant increase in Fos expression in vasopressin cells of the PC and SON. Thus, functionally distinct populations of vasopressin cells are implicated in olfactory processing at multiple stages of the olfactory pathway.
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Affiliation(s)
- C Tsuji
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - T Tsuji
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - A Allchorne
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - G Leng
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - M Ludwig
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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17
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Abstract
AIMS Alzheimer's disease (AD) is characterized by cholinergic dysfunction and deposition of β-amyloid (Aβ) plaques and tau neurofibrillary tangles (NFTs) in the brain. Olfactory abnormalities often precede cognitive symptoms in AD, indicating early involvement of pathology in olfactory structures. The cholinergic system is important not only in cognition but also in modulation of the olfactory system. The primary olfactory gyrus (POG) is comprised of the olfactory tract, anterior olfactory nucleus (AON) and olfactory area (OA). Because of the importance of the olfactory and cholinergic systems, we examined the anatomical and cholinergic organization of the POG in normal human brain and neuropathology in AD. METHODS Cytoarchitecture of the POG was studied using Nissl staining in normal (n = 8) and AD (n = 6) brains. Distributions of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined using histochemical methods. Aβ plaques and tau NFTs were detected using immunohistochemistry. Abundance of AD pathology was assessed using a semi-quantitative approach. RESULT Nissl staining showed pyramidal cells in the AON and paleocortical organization of the OA. AChE stained neurons and neuropil in the AON and OA, while BChE activity was noted in the olfactory tract and in AON and OA neurons. Pathology was frequent in the AD POG and the abundance of BChE-associated AD pathology was greater than that associated with AChE. CONCLUSIONS AChE and BChE activities in normal POG recapitulated their distributions in other cortical regions. Greater abundance of BChE-associated, in comparison to AChE-associated, AD pathology in the POG suggests preferential involvement of BChE in olfactory dysfunction in AD.
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Affiliation(s)
- H Hamodat
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - M K Cash
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - J D Fisk
- Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, NS, Canada.,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
| | - S Darvesh
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada.,Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, NS, Canada.,Division of Neurology, Department of Medicine, Dalhousie University, Halifax, NS, Canada.,Department of Chemistry and Physics, Mount St. Vincent University, Halifax, NS, Canada
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18
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Esquivelzeta Rabell J, Mutlu K, Noutel J, Martin Del Olmo P, Haesler S. Spontaneous Rapid Odor Source Localization Behavior Requires Interhemispheric Communication. Curr Biol 2017; 27:1542-1548.e4. [PMID: 28502658 DOI: 10.1016/j.cub.2017.04.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/14/2017] [Accepted: 04/14/2017] [Indexed: 12/14/2022]
Abstract
Navigation, finding food sources, and avoiding danger critically depend on the identification and spatial localization of airborne chemicals. When monitoring the olfactory environment, rodents spontaneously engage in active olfactory sampling behavior, also referred to as exploratory sniffing [1]. Exploratory sniffing is characterized by stereotypical high-frequency respiration, which is also reliably evoked by novel odorant stimuli [2, 3]. To study novelty-induced exploratory sniffing, we developed a novel, non-contact method for measuring respiration by infrared (IR) thermography in a behavioral paradigm in which novel and familiar stimuli are presented to head-restrained mice. We validated the method by simultaneously performing nasal pressure measurements, a commonly used invasive approach [2, 4], and confirmed highly reliable detection of inhalation onsets. We further discovered that mice actively orient their nostrils toward novel, previously unexperienced, smells. In line with the remarkable speed of olfactory processing reported previously [3, 5, 6], we find that mice initiate their response already within the first sniff after odor onset. Moreover, transecting the anterior commissure (AC) disrupted orienting, indicating that the orienting response requires interhemispheric transfer of information. This suggests that mice compare odorant information obtained from the two bilaterally symmetric nostrils to locate the source of the novel odorant. We further demonstrate that asymmetric activation of the anterior olfactory nucleus (AON) is both necessary and sufficient for eliciting orienting responses. These findings support the view that the AON plays an important role in the internostril difference comparison underlying rapid odor source localization.
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Affiliation(s)
- José Esquivelzeta Rabell
- Neuroelectronics Research Flanders, 3001 Leuven, Belgium; Department of Neurosciences, KU Leuven, 3001 Leuven, Belgium
| | - Kadir Mutlu
- Neuroelectronics Research Flanders, 3001 Leuven, Belgium; Department of Neurosciences, KU Leuven, 3001 Leuven, Belgium
| | - João Noutel
- Neuroelectronics Research Flanders, 3001 Leuven, Belgium; VIB, 3001 Leuven, Belgium
| | | | - Sebastian Haesler
- Neuroelectronics Research Flanders, 3001 Leuven, Belgium; Department of Neurosciences, KU Leuven, 3001 Leuven, Belgium; VIB, 3001 Leuven, Belgium; Imec, 3001 Leuven, Belgium.
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19
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Oettl LL, Ravi N, Schneider M, Scheller MF, Schneider P, Mitre M, da Silva Gouveia M, Froemke RC, Chao MV, Young WS, Meyer-Lindenberg A, Grinevich V, Shusterman R, Kelsch W. Oxytocin Enhances Social Recognition by Modulating Cortical Control of Early Olfactory Processing. Neuron 2016; 90:609-21. [PMID: 27112498 DOI: 10.1016/j.neuron.2016.03.033] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 02/17/2016] [Accepted: 03/15/2016] [Indexed: 11/19/2022]
Abstract
Oxytocin promotes social interactions and recognition of conspecifics that rely on olfaction in most species. The circuit mechanisms through which oxytocin modifies olfactory processing are incompletely understood. Here, we observed that optogenetically induced oxytocin release enhanced olfactory exploration and same-sex recognition of adult rats. Consistent with oxytocin's function in the anterior olfactory cortex, particularly in social cue processing, region-selective receptor deletion impaired social recognition but left odor discrimination and recognition intact outside a social context. Oxytocin transiently increased the drive of the anterior olfactory cortex projecting to olfactory bulb interneurons. Cortical top-down recruitment of interneurons dynamically enhanced the inhibitory input to olfactory bulb projection neurons and increased the signal-to-noise of their output. In summary, oxytocin generates states for optimized information extraction in an early cortical top-down network that is required for social interactions with potential implications for sensory processing deficits in autism spectrum disorders.
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Affiliation(s)
- Lars-Lennart Oettl
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Namasivayam Ravi
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Miriam Schneider
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Max F Scheller
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Peggy Schneider
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Mariela Mitre
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Miriam da Silva Gouveia
- Schaller Research Group on Neuropeptides, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Robert C Froemke
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Moses V Chao
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - W Scott Young
- Section on Neural Gene Expression, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - Andreas Meyer-Lindenberg
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany
| | - Valery Grinevich
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany; Schaller Research Group on Neuropeptides, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Roman Shusterman
- Sagol Department of Neurobiology, University of Haifa, Haifa 3498838, Israel
| | - Wolfgang Kelsch
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159 Mannheim, Germany.
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20
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Abstract
Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals.
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Affiliation(s)
- Peter C Brunjes
- Department Psychology, University of Virginia, 102 Gilmer Hall, PO Box 400400, Charlottesville, VA 22904, USA and
| | - Sanford Feldman
- Department of Comparative Medicine, University of Virginia, 102 Gilmer Hall, PO Box 400400, Charlottesville, VA 22904, USA
| | - Stephen K Osterberg
- Department Psychology, University of Virginia, 102 Gilmer Hall, PO Box 400400, Charlottesville, VA 22904, USA and
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21
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Abstract
Processing of sensory information is substantially shaped by centrifugal, or feedback, projections from higher cortical areas, yet the functional properties of these projections are poorly characterized. Here, we used genetically-encoded calcium sensors (GCaMPs) to functionally image activation of centrifugal projections targeting the olfactory bulb (OB). The OB receives massive centrifugal input from cortical areas but there has been as yet no characterization of their activity in vivo. We focused on projections to the OB from the anterior olfactory nucleus (AON), a major source of cortical feedback to the OB. We expressed GCaMP selectively in AON projection neurons using a mouse line expressing Cre recombinase (Cre) in these neurons and Cre-dependent viral vectors injected into AON, allowing us to image GCaMP fluorescence signals from their axon terminals in the OB. Electrical stimulation of AON evoked large fluorescence signals that could be imaged from the dorsal OB surface in vivo. Surprisingly, odorants also evoked large signals that were transient and coupled to odorant inhalation both in the anesthetized and awake mouse, suggesting that feedback from AON to the OB is rapid and robust across different brain states. The strength of AON feedback signals increased during wakefulness, suggesting a state-dependent modulation of cortical feedback to the OB. Two-photon GCaMP imaging revealed that different odorants activated different subsets of centrifugal AON axons and could elicit both excitation and suppression in different axons, indicating a surprising richness in the representation of odor information by cortical feedback to the OB. Finally, we found that activating neuromodulatory centers such as basal forebrain drove AON inputs to the OB independent of odorant stimulation. Our results point to the AON as a multifunctional cortical area that provides ongoing feedback to the OB and also serves as a descending relay for other neuromodulatory systems.
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Affiliation(s)
- Markus Rothermel
- Brain Institute and Department of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
| | - Matt Wachowiak
- Brain Institute and Department of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA
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22
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Brunjes PC, Collins LN, Osterberg SK, Phillips AM. The mouse olfactory peduncle. 3. Development of neurons, glia, and centrifugal afferents. Front Neuroanat 2014; 8:44. [PMID: 24926238 PMCID: PMC4046489 DOI: 10.3389/fnana.2014.00044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/19/2014] [Indexed: 11/14/2022] Open
Abstract
The present series of studies was designed to provide a general overview of the development of the region connecting the olfactory bulb to the forebrain. The olfactory peduncle (OP) contains several structures involved in processing odor information with the anterior olfactory nucleus (cortex) being the largest and most studied. Results indicate that considerable growth occurs in the peduncle from postnatal day (P)10–P20, with reduced expansion from P20 to P30. No evidence was found for the addition of new projection or interneurons during the postnatal period. GABAergic cells decreased in both number and density after P10. Glial populations exhibited different patterns of development, with astrocytes declining in density from P10 to P30, and both oligodendrocytes and microglia increasing through the interval. Myelination in the anterior commissure emerged between P11 and P14. Dense cholinergic innervation was observed at P10 and remained relatively stable through P30, while considerable maturation of serotonergic innervation occurred through the period. Unilateral naris occlusion from P1 to P30 resulted in about a 30% reduction in the size of the ipsilateral peduncle but few changes were observed on the contralateral side. The ipsilateral peduncle also exhibited higher densities of GAD67-containing interneurons and cholinergic fibers suggesting a delay in normal developmental pruning. Lower densities of interneurons expressing CCK, somatostatin, and NPY and in myelin basic protein staining were also observed. Understanding variations in developmental trajectories within the OP may be an important tool for unraveling the functions of the region.
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Affiliation(s)
- Peter C Brunjes
- Department of Psychology, University of Virginia, Charlottesville VA, USA
| | - Lindsay N Collins
- Department of Psychology, University of Virginia, Charlottesville VA, USA
| | | | - Adriana M Phillips
- Department of Psychology, University of Virginia, Charlottesville VA, USA
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23
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Doorn KJ, Goudriaan A, Blits‐Huizinga C, Bol JG, Rozemuller AJ, Hoogland PV, Lucassen PJ, Drukarch B, van de Berg WD, van Dam A. Increased amoeboid microglial density in the olfactory bulb of Parkinson's and Alzheimer's patients. Brain Pathol 2014; 24:152-65. [PMID: 24033473 PMCID: PMC8029318 DOI: 10.1111/bpa.12088] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/12/2013] [Indexed: 12/31/2022] Open
Abstract
The olfactory bulb (OB) is affected early in both Parkinson's (PD) and Alzheimer's disease (AD), evidenced by the presence of disease-specific protein aggregates and an early loss of olfaction. Whereas previous studies showed amoeboid microglia in the classically affected brain regions of PD and AD patients, little was known about such changes in the OB. Using a morphometric approach, a significant increase in amoeboid microglia density within the anterior olfactory nucleus (AON) of AD and PD patients was observed. These amoeboid microglia cells were in close apposition to β-amyloid, hyperphosphorylated tau or α-synuclein deposits, but no uptake of pathological proteins by microglia could be visualized. Subsequent analysis showed (i) no correlation between microglia and α-synuclein (PD), (ii) a positive correlation with β-amyloid (AD), and (iii) a negative correlation with hyperphosphorylated tau (AD). Furthermore, despite the observed pathological alterations in neurite morphology, neuronal loss was not apparent in the AON of both patient groups. Thus, we hypothesize that, in contrast to the classically affected brain regions of AD and PD patients, within the AON rather than neuronal loss, the increased density in amoeboid microglial cells, possibly in combination with neurite pathology, may contribute to functional deficits.
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Affiliation(s)
- Karlijn J. Doorn
- Swammerdam Institute for Life SciencesCenter for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Andrea Goudriaan
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
- Present address:
VU UniversityFaculty of Earth and Life Sciences, Department of Molecular and Cellular NeurobiologyAmsterdamThe Netherlands
| | - Carla Blits‐Huizinga
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - John G.J.M. Bol
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Annemieke J. Rozemuller
- Department of PathologyVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Piet V.J.M. Hoogland
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Paul J. Lucassen
- Swammerdam Institute for Life SciencesCenter for NeuroscienceUniversity of AmsterdamAmsterdamThe Netherlands
| | - Benjamin Drukarch
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Wilma D.J. van de Berg
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
| | - Anne‐Marie van Dam
- Department of Anatomy and NeurosciencesVU University Medical Center, Neuroscience Campus AmsterdamAmsterdamThe Netherlands
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Scholl EA, Dudek FE, Ekstrand JJ. Neuronal degeneration is observed in multiple regions outside the hippocampus after lithium pilocarpine-induced status epilepticus in the immature rat. Neuroscience 2013; 252:45-59. [PMID: 23896573 DOI: 10.1016/j.neuroscience.2013.07.045] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 01/25/2023]
Abstract
Although hippocampal sclerosis is frequently identified as a possible epileptic focus in patients with temporal lobe epilepsy, neuronal loss has also been observed in additional structures, including areas outside the temporal lobe. The claim from several researchers using animal models of acquired epilepsy that the immature brain can develop epilepsy without evidence of hippocampal neuronal death raises the possibility that neuronal death in some of these other regions may also be important for epileptogenesis. The present study used the lithium pilocarpine model of acquired epilepsy in immature animals to assess which structures outside the hippocampus are injured acutely after status epilepticus. Sprague-Dawley rat pups were implanted with surface EEG electrodes, and status epilepticus was induced at 20 days of age with lithium pilocarpine. After 72 h, brain tissue from 12 animals was examined with Fluoro-Jade B, a histochemical marker for degenerating neurons. All animals that had confirmed status epilepticus demonstrated Fluoro-Jade B staining in areas outside the hippocampus. The most prominent staining was seen in the thalamus (mediodorsal, paratenial, reuniens, and ventral lateral geniculate nuclei), amygdala (ventral lateral, posteromedial, and basomedial nuclei), ventral premammillary nuclei of hypothalamus, and paralimbic cortices (perirhinal, entorhinal, and piriform) as well as parasubiculum and dorsal endopiriform nuclei. These results demonstrate that lithium pilocarpine-induced status epilepticus in the immature rat brain consistently results in neuronal injury in several distinct areas outside of the hippocampus. Many of these regions are similar to areas damaged in patients with temporal lobe epilepsy, thus suggesting a possible role in epileptogenesis.
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Key Words
- AA
- ACH
- ACo
- AD
- AHC
- AI
- AM
- AO
- APir
- AStr
- AV
- Acb
- AcbSh
- BAOT
- BLA
- BLP
- BLV
- BMA
- BMP
- BSTIA
- BSTM
- CA
- CL
- CM
- CPu
- CeL
- CeM
- Cg1-3
- DEn
- DG
- DI
- DLG
- DP
- EEG
- Ent
- Fluoro-jade B
- Fr1-3
- GABA
- GI
- GP
- HC
- Hil
- I
- IL
- LDDM
- LDVL
- LHb
- LM
- LO
- LOT
- LPLR
- LPMR
- LSD
- LSI
- LSV
- LaD
- LaV
- MD
- MGD
- MGM
- MGP
- MGV
- MHb
- MO
- MS
- MTu
- MeA
- MePD
- MePV
- NAc
- Oc2L
- P
- PC
- PF
- PLCo
- PMCo
- PMD
- PMV
- PRh
- PT
- PVA
- PVP
- PaS
- Par1
- Pir
- Po
- PrS
- RSA
- RSG
- Re
- Rh
- Rt
- S
- SG
- SI
- SNR
- STh
- TLE
- Te1,3
- VL
- VLG
- VLO
- VM
- VP
- VPL
- VPM
- VTR
- ZI
- accumbens
- accumbens shell
- agranular insular cortex
- amygdalopiriform transition area
- amygdalostriatal transition area
- anterior amygdaloid area
- anterior cingulate
- anterior cortical nucleus
- anterior hypothalamic area
- anterior hypothalamic area, central
- anterior olfactory nucleus
- anterodorsal nucleus
- anteromedial
- anteroventral nucleus
- basolateral nucleus, anterior
- basolateral nucleus, posterior
- basolateral nucleus, ventral
- basomedial nucleus, anterior
- basomedial nucleus, posterior
- bed nucleus accessory olfactory tract
- bed nucleus stria terminalis, intraamygdaloid division
- bed stria terminalis nuclei
- caudate putamen
- central nucleus, lateral
- central nucleus, medial
- centrolateral nucleus
- centromedial nucleus
- cornu ammonis
- dentate gyrus
- dorsal endopiriform nucleus
- dorsal peduncular
- dorsolateral geniculate nucleus
- dysgranular insular cortex
- electroencephalogram
- entorhinal cortex
- frontal cortex
- globus pallidus
- granular insular cortex
- hilus
- hippocampus
- immature brain
- infralimbic
- intercalated masses
- lateral habenula
- lateral mammillary
- lateral nucleus, dorsal
- lateral nucleus, ventral
- lateral orbital cortex
- lateral septal, dorsal
- lateral septal, intermediate
- lateral septal, ventral
- laterodorsal nucleus, dorsomedial
- laterodorsal nucleus, ventrolateral
- lateroposterior nucleus, lateral rostral
- lateroposterior nucleus, medial rostral
- lithium pilocarpine
- medial geniculate nucleus, dorsal
- medial geniculate nucleus, medial
- medial geniculate nucleus, ventral
- medial globus pallidus
- medial habenula
- medial nucleus, anterior
- medial nucleus, posterodorsal
- medial nucleus, posteroventral
- medial orbital cortex
- medial septal
- medial tuberal
- mediodorsal nucleus
- nucleus accumbens
- nucleus lateral olfactory tract
- occipital cortex
- paracentral
- parafasicular
- parasubiculum
- paratenial
- paraventricular nucleus, anterior
- paraventricular nucleus, posterior
- parietal cortex
- perirhinal cortex
- piriform cortex
- post-natal day
- posterior nucleus
- posterolateral cortical nucleus
- posteromedial cortical nucleus
- premammillary nucleus, dorsal
- premammillary nucleus, ventral
- presubiculum
- reticular nucleus
- retrosplenial agranular cortex
- retrosplenial granular cortex
- reuniens nucleus
- rhomboid nucleus
- status epilepticus
- subiculum
- substantia innominate
- substantia nigra pars reticulate
- subthalamic nucleus
- suprageniculate nucleus
- temporal cortex
- temporal lobe epilepsy
- vRe
- ventral pallidum
- ventral posterolateral nucleus
- ventral posteromedial nucleus
- ventral reuniens nucleus
- ventral tegmental area
- ventrolateral geniculate nucleus
- ventrolateral nucleus
- ventrolateral orbital cortex
- ventromedial nucleus
- zona incerta
- γ-aminobutyric acid
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Affiliation(s)
- E A Scholl
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States
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Zimmermann B, Girard F, Mészàr Z, Celio MR. Expression of the calcium binding proteins Necab-1,-2 and -3 in the adult mouse hippocampus and dentate gyrus. Brain Res 2013; 1528:1-7. [PMID: 23850650 DOI: 10.1016/j.brainres.2013.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/24/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022]
Abstract
The family of EF-hand calcium binding proteins is composed of more than 250 members. In search for other neuronal markers, we studied the expression pattern of Necab-1, -2 and -3 in the Ammons horn of adult mice at the gene- and protein levels using in-situ hybridization and immunohistochemistry. The genes for the three Necab's were expressed in specific, non-overlapping areas of the hippocampus. A minority of the Necab-positive interneurons were GABA-ergic, and they virtually never coexpressed one of the classical calcium binding proteins (calretinin, calbindin D-28k and parvalbumin). Necab's are promising new neuronal markers in the brain.
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Affiliation(s)
- B Zimmermann
- Division of Anatomy and Program in Neuroscience, University of Fribourg, Rte. A.Gockel 1, CH-1700 Fribourg, Switzerland
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Larriva-Sahd J. Cytological organization of the alpha component of the anterior olfactory nucleus and olfactory limbus. Front Neuroanat 2012; 6:23. [PMID: 22754506 PMCID: PMC3384266 DOI: 10.3389/fnana.2012.00023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 06/06/2012] [Indexed: 11/26/2022] Open
Abstract
This study describes the microscopic organization of a wedge-shaped area at the intersection of the main (MOB) and accessory olfactory bulbs (AOBs), or olfactory limbus (OL), and an additional component of the anterior olfactory nucleus or alpha AON that lies underneath of the AOB. The OL consists of a modified bulbar cortex bounded anteriorly by the MOB and posteriorly by the AOB. In Nissl-stained specimens the OL differs from the MOB by a progressive, antero-posterior decrease in thickness or absence of the external plexiform, mitral/tufted cell, and granule cell layers. On cytoarchitectual grounds the OL is divided from rostral to caudal into three distinct components: a stripe of glomerular-free cortex or preolfactory area (PA), a second or necklace glomerular area, and a wedge-shaped or interstitial area (INA) crowned by the so-called modified glomeruli that appear to belong to the anterior AOB. The strategic location and interactions with the main and AOBs, together with the previously noted functional and connectional evidence, suggest that the OL may be related to both sensory modalities. The alpha component of the anterior olfactory nucleus, a slender cellular cluster (i.e., 650 × 150 μm) paralleling the base of the AOB, contains two neuron types: a pyramidal-like neuron and an interneuron. Dendrites of pyramidal-like cells (P-L) organize into a single bundle that ascends avoiding the AOB to resolve in a trigone bounded by the edge of the OL, the AOB and the dorsal part of the anterior olfactory nucleus. Utrastructurally, the neuropil of the alpha component contains three types of synaptic terminals; one of them immunoreactive to the enzyme glutamate decarboxylase, isoform 67.
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Affiliation(s)
- Jorge Larriva-Sahd
- Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
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Hagiwara A, Pal SK, Sato TF, Wienisch M, Murthy VN. Optophysiological analysis of associational circuits in the olfactory cortex. Front Neural Circuits 2012; 6:18. [PMID: 22529781 PMCID: PMC3329886 DOI: 10.3389/fncir.2012.00018] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/26/2012] [Indexed: 02/04/2023] Open
Abstract
Primary olfactory cortical areas receive direct input from the olfactory bulb, but also have extensive associational connections that have been mainly studied with classical anatomical methods. Here, we shed light on the functional properties of associational connections in the anterior and posterior piriform cortices (aPC and pPC) using optophysiological methods. We found that the aPC receives dense functional connections from the anterior olfactory nucleus (AON), a major hub in olfactory cortical circuits. The local recurrent connectivity within the aPC, long invoked in cortical autoassociative models, is sparse and weak. By contrast, the pPC receives negligible input from the AON, but has dense connections from the aPC as well as more local recurrent connections than the aPC. Finally, there are negligible functional connections from the pPC to aPC. Our study provides a circuit basis for a more sensory role for the aPC in odor processing and an associative role for the pPC.
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Affiliation(s)
- Akari Hagiwara
- Akari Hagiwara, Faculty of Medicine, Department of Biochemistry, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan. e-mail:
| | | | | | | | - Venkatesh N. Murthy
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, CambridgeMA, USA
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Imabayashi E, Matsuda H, Yoshimaru K, Kuji I, Seto A, Shimano Y, Ito K, Kikuta D, Shimazu T, Araki N. Pilot data on telmisartan short-term effects on glucose metabolism in the olfactory tract in Alzheimer's disease. Brain Behav 2011; 1:63-9. [PMID: 22399085 PMCID: PMC3236542 DOI: 10.1002/brb3.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 12/26/2022] Open
Abstract
The possible effect of antihypertensive therapy on Alzheimer's disease (AD) has been studied, and angiotensin II receptor blockers (ARBs) have been suggested to exert an effect on cognitive decline. The purpose of this study is to clarify the functional effects of telmisartan, a long-acting ARB, on AD brain using prospective longitudinal (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) studies. For this purpose, brain glucose metabolism of four hypertensive patients with AD was examined with FDG-PET before and after administration of telmisartan. Studied subjects underwent three FDG-PET studies at intervals of 12 weeks. Antihypertensive treatment except for telmisartan was started after the first FDG-PET and continued for 24 weeks. Then 40-80 mg of telmisartan was added after the second FDG-PET and continued for 12 weeks.Glucose metabolism was significantly decreased during the first 12 weeks without telmisartan use at an area (-10, 21, -22, x, y, z; Z = 3.56) caudal to the left rectal gyrus and the olfactory sulcus corresponding to the left olfactory tract. In contrast, the introduction of telmisartan during the following 12 weeks preserved glucose metabolism at areas (5, 19, -20, x, y, z; Z = 3.09; 6, 19, -22, x, y, z; Z = 2.88) caudal to the bilateral rectal gyri and olfactory sulci corresponding to the bilateral olfactory tracts. No areas showed decreased glucose metabolism after the introduction of telmisartan. In AD, amyloid-β deposition is observed in the anterior olfactory nucleus (AON) of the olfactory tract. Glucose metabolism in AON may be progressively decreased and preserved by telmisartan.
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Affiliation(s)
- Etsuko Imabayashi
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Hiroshi Matsuda
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Kimiko Yoshimaru
- Department of Neurology, Saitama Medial University Hospital38 Morohongo, Moroyama, Iruma-gun, Saitama, Japan
| | - Ichiei Kuji
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Akira Seto
- Department of Nuclear Medicine, Saitama Medial University Hospital38 Morohongo, Moroyama, Iruma-gun, Saitama, Japan
| | - Yasumasa Shimano
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Kimiteru Ito
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Daisuke Kikuta
- Department of Nuclear Medicine, Saitama Medical University International Medical Center1397-1 Yamane, Hidaka, Saitama, Japan
| | - Tomokazu Shimazu
- Department of Neurology, Saitama Medial University Hospital38 Morohongo, Moroyama, Iruma-gun, Saitama, Japan
| | - Nobuo Araki
- Department of Neurology, Saitama Medial University Hospital38 Morohongo, Moroyama, Iruma-gun, Saitama, Japan
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