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Wang Q, Ren H, Li Z, Li J, Dai L, Dong M, Zhou J, He J, Chen X, Gu L, He Y, Tang J. Differences in olfactory dysfunction and its relationship with cognitive function in schizophrenia patients with and without auditory verbal hallucinations. Eur Arch Psychiatry Clin Neurosci 2023; 273:1813-1824. [PMID: 36949249 DOI: 10.1007/s00406-023-01589-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 03/06/2023] [Indexed: 03/24/2023]
Abstract
Olfactory discrimination dysfunction has been observed in patients with schizophrenia (SCZ), but its relationship with cognitive function has not been clarified. The purpose of this study was to examine the differences in olfactory identification function in SCZ patients with and without auditory verbal hallucinations (AVHs) and its relationship with cognitive function. Olfactory identification function was measured in 80 SCZ patients with AVHs, 57 SCZ patients without AVHs, and 87 healthy controls (HC). Clinical symptom scores and neuropsychological measures were also administered to all corresponding subjects. Compared to HC, SCZ patients showed significant deficits in olfactory identification and cognitive function, but there were no differences in olfactory identification dysfunction and cognitive dysfunction between the two subgroups. In the non-AVHs subgroup only, poorer Olfactory Stick Identification Test for Japanese (OSIT-J) scores were significantly and positively correlated with total and delayed recall (Bonferroni correction, p < 0.002). Stepwise regression analysis revealed that factors affecting olfactory identification impairment differed in the two SCZ patient subgroups. In conclusion, this study highlights the commonality of olfactory identification dysfunction in SCZ patients and the importance of olfactory assessment of different subtypes of SCZ patients.
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Affiliation(s)
- Qianjin Wang
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Honghong Ren
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong, China
| | - Zongchang Li
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jinguang Li
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Lulin Dai
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Min Dong
- Guangdong Mental Health Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China
| | - Jun Zhou
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jingqi He
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xiaogang Chen
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | | | - Ying He
- Department of Psychiatry, and National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Jinsong Tang
- Department of Psychiatry, Sir Run-Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China.
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Smith RC, Sershen H, Youssef M, Lajtha A, Jin H, Zhang M, Chen A, Guidotti A, Davis JM. Deficits in odor discrimination versus odor identification in patients with schizophrenia and negative correlations with GABAergic and DNA methyltransferase mRNAs in lymphocytes. Front Psychiatry 2023; 14:1115399. [PMID: 37056402 PMCID: PMC10088370 DOI: 10.3389/fpsyt.2023.1115399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 03/02/2023] [Indexed: 04/15/2023] Open
Abstract
Introduction People with schizophrenia have been reported to show deficits in tests of olfactory function. DNA methylation and GABAergic input have been implicated in biochemical processes controlling odor in animal studies, but this has not been investigated in human studies. Methods In a study of measures of DNA methylation and GABAergic mRNAs in lymphocytes, we also measured odor identification and discrimination with the Sniffin' Sticks battery in 58 patients with chronic schizophrenia (CSZ) and 48 controls. mRNAs in lymphocytes were assessed by qPCR using TaqManTM probes. Cognition was assessed by the MATRICS battery (Measurement and Treatment Research to Improve Cognition in Schizophrenia) in CSZ and controls, and symptoms in CSZ were assessed by PANSS scale (Positive and Negative Symptom Scale). The relationships of odor deficits with mRNA, cognition, and symptoms were explored by correlation analysis. Variables which significantly differentiated CSZ from controls were explored by logistic regression. Results Overall, CSZ showed significantly (P≤.001) lower scores on odor discrimination compared to controls, with a moderate effect size, but no difference in odor identification. Deficits in odor discrimination, which has not been standardly assessed in many prior studies, strongly differentiated CSZ from controls. In logistic regression analysis, odor discrimination, but not odor identification, was a significant variable predicting schizophrenia versus control class membership. This is the first study to report relationship between odor deficits and DNA methylation and GABAergic mRNAs in blood cells of human subjects. There were negative correlations of odor identification with DNA methylation enzymes mRNAs and significant negative correlations with odor discrimination and GABAergic mRNAs. Lower odor scores were significantly associated with lower cognitive scores on the MATRICS battery in CSZ but not control subjects. In CSZ, lower odor scores were significantly associated with negative symptom scores, while higher odor identification scores were associated with PANNS Excitement factor. Discussion Odor discrimination was a more powerful variable than odor identification in discriminating CSZ from controls and should be used more regularly as an odor measure in studies of schizophrenia. The substantive meaning of the negative correlations of odor discrimination and GABAergic mRNA variables in peripheral lymphocytes of CSZ needs more investigation and comparison with results in neural tissue.
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Affiliation(s)
- Robert C. Smith
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, United States
- *Correspondence: Robert C. Smith, ;
| | - Henry Sershen
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, United States
| | - Mary Youssef
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
| | - Abel Lajtha
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, United States
| | - Hua Jin
- Department of Psychiatry and VA San Diego Healthcare System, University of California San Diego, San Diego, CA, United States
| | - Mumei Zhang
- Columbia University Mailman School of Public Health, New York, NY, United States
| | - Anmei Chen
- Columbia University Mailman School of Public Health, New York, NY, United States
| | - Alessandro Guidotti
- Department of Psychiatry, Psychiatric Institute University of Illinois, Chicago, IL, United States
| | - John M. Davis
- Department of Psychiatry, Psychiatric Institute University of Illinois, Chicago, IL, United States
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Olfactory impairment in psychiatric disorders: Does nasal inflammation impact disease psychophysiology? Transl Psychiatry 2022; 12:314. [PMID: 35927242 PMCID: PMC9352903 DOI: 10.1038/s41398-022-02081-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 07/14/2022] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
Olfactory impairments contribute to the psychopathology of mental illnesses such as schizophrenia and depression. Recent neuroscience research has shed light on the previously underappreciated olfactory neural circuits involved in regulation of higher brain functions. Although environmental factors such as air pollutants and respiratory viral infections are known to contribute to the risk for psychiatric disorders, the role of nasal inflammation in neurobehavioral outcomes and disease pathophysiology remains poorly understood. Here, we will first provide an overview of published findings on the impact of nasal inflammation in the olfactory system. We will then summarize clinical studies on olfactory impairments in schizophrenia and depression, followed by preclinical evidence on the neurobehavioral outcomes produced by olfactory dysfunction. Lastly, we will discuss the potential impact of nasal inflammation on brain development and function, as well as how we can address the role of nasal inflammation in the pathophysiological mechanisms underlying psychiatric disorders. Considering the current outbreak of Coronavirus Disease 2019 (COVID-19), which often causes nasal inflammation and serious adverse effects for olfactory function that might result in long-lasting neuropsychiatric sequelae, this line of research is particularly critical to understanding of the potential significance of nasal inflammation in the pathophysiology of psychiatric disorders.
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Hidalgo S, Campusano JM, Hodge JJL. Assessing olfactory, memory, social and circadian phenotypes associated with schizophrenia in a genetic model based on Rim. Transl Psychiatry 2021; 11:292. [PMID: 34001859 PMCID: PMC8128896 DOI: 10.1038/s41398-021-01418-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 04/22/2021] [Accepted: 04/30/2021] [Indexed: 02/04/2023] Open
Abstract
Schizophrenia shows high heritability and several of the genes associated with this disorder are involved in calcium (Ca2+) signalling and synaptic function. One of these is the Rab-3 interacting molecule-1 (RIM1), which has recently been associated with schizophrenia by Genome Wide Association Studies (GWAS). However, its contribution to the pathophysiology of this disorder remains unexplored. In this work, we use Drosophila mutants of the orthologue of RIM1, Rim, to model some aspects of the classical and non-classical symptoms of schizophrenia. Rim mutants showed several behavioural features relevant to schizophrenia including social distancing and altered olfactory processing. These defects were accompanied by reduced evoked Ca2+ influx and structural changes in the presynaptic terminals sent by the primary olfactory neurons to higher processing centres. In contrast, expression of Rim-RNAi in the mushroom bodies (MBs), the main memory centre in flies, spared learning and memory suggesting a differential role of Rim in different synapses. Circadian deficits have been reported in schizophrenia. We observed circadian locomotor activity deficits in Rim mutants, revealing a role of Rim in the pacemaker ventral lateral clock neurons (LNvs). These changes were accompanied by impaired day/night remodelling of dorsal terminal synapses from a subpopulation of LNvs and impaired day/night release of the circadian neuropeptide pigment dispersing factor (PDF) from these terminals. Lastly, treatment with the commonly used antipsychotic haloperidol rescued Rim locomotor deficits to wildtype. This work characterises the role of Rim in synaptic functions underlying behaviours disrupted in schizophrenia.
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Affiliation(s)
- Sergio Hidalgo
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Science, University of Bristol, Bristol, UK
| | - Jorge M Campusano
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Science, University of Bristol, Bristol, UK.
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Liu S. Dopamine Suppresses Synaptic Responses of Fan Cells in the Lateral Entorhinal Cortex to Olfactory Bulb Input in Mice. Front Cell Neurosci 2020; 14:181. [PMID: 32625065 PMCID: PMC7316158 DOI: 10.3389/fncel.2020.00181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 05/27/2020] [Indexed: 01/11/2023] Open
Abstract
The lateral entorhinal cortex (LEC) is involved in odor discrimination, odor-associative multimodal memory, and neurological or neuropsychiatric disorders. It receives direct axonal projections from both olfactory bulb (OB) output neurons and midbrain dopaminergic neurons. However, the cellular targets in LEC receiving direct synaptic input from OB output neuron, the functional characteristics of these synapses, and whether or how dopamine (DA) modulates the OB-LEC pathway remain undetermined. We addressed these questions in the present study by combing optogenetic and electrophysiological approaches with four major findings: (1) selective activation of OB input elicited glutamate-mediated monosynaptic responses in all fan cells, the major output neurons in layer II of the LEC; (2) this excitatory synaptic transmission exhibited robust paired-pulse facilitation (PPF), a presynaptically derived short-term synaptic plasticity; (3) DA dramatically attenuated the strength of the OB input-fan cell synaptic transmission via activation of D1 receptors; and (4) DA altered the PPF of this transmission but neither intrinsic properties of postsynaptic neurons nor the kinetic profile of postsynaptic responses, suggesting that presynaptic mechanisms underlie the DA inhibitory actions. This study for the first time demonstrates the FCs in the LEC layer II as the postsynaptic target of direct OB input and characterizes DA modulation of the OB input-fan cell pathway. These findings set the foundation for future studies to examine the synaptic transmission from the OB output neuron axon terminals to other potential cell types in the LEC and to pinpoint the pathophysiological mechanisms underlying olfactory deficits associated with DA-relevant neurological and neuropsychiatric disorders.
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Affiliation(s)
- Shaolin Liu
- Department of Anatomy, Howard University College of Medicine, Washington, DC, United States
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6
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Hidalgo S, Castro C, Zárate RV, Valderrama BP, Hodge JJL, Campusano JM. The behavioral and neurochemical characterization of a Drosophila dysbindin mutant supports the contribution of serotonin to schizophrenia negative symptoms. Neurochem Int 2020; 138:104753. [PMID: 32416114 DOI: 10.1016/j.neuint.2020.104753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/09/2020] [Accepted: 05/08/2020] [Indexed: 01/03/2023]
Abstract
Mutations in the dystrobrevin binding protein 1 (DTNBP1) gene that encodes for the dysbindin-1 protein, are associated with a higher risk for schizophrenia. Interestingly, individuals carrying high-risk alleles in this gene have been associated with an increased incidence of negative symptoms for the disease, which include anhedonia, avolition and social withdrawal. Here we evaluated behavioral and neurochemical changes in a hypomorphic Drosophila mutant for the orthologue of human Dysbindin-1, dysb1. Mutant dysb1 flies exhibit altered social space parameters, suggesting asocial behavior, accompanied by reduced olfactory performance. Moreover, dysb1 mutant flies show poor performance in basal and startle-induced locomotor activity. We also report a reduction in serotonin brain levels and changes in the expression of the Drosophila serotonin transporter (dSERT) in dysb1 flies. Our data show that the serotonin-releasing amphetamine derivative 4-methylthioamphetamine (4-MTA) modulates social spacing and locomotion in control flies, suggesting that serotonergic circuits modulate these behaviors. 4-MTA was unable to modify the behavioral deficiencies in mutant flies, which is consistent with the idea that the efficiency of pharmacological agents acting at dSERT depends on functional serotonergic circuits. Thus, our data show that the dysb1 mutant exhibits behavioral deficits that mirror some aspects of the endophenotypes associated with the negative symptoms of schizophrenia. We argue that at least part of the behavioral aspects associated with these symptoms could be explained by a serotonergic deficit. The dysb1 mutant presents an opportunity to study the molecular underpinnings of schizophrenia negative symptoms and reveals new potential targets for treatment of the disease.
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Affiliation(s)
- Sergio Hidalgo
- Departamento de Biología Cellular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile; School of Physiology, Pharmacology and Neuroscience, Faculty of Life Science, University of Bristol, UK.
| | - Christian Castro
- Departamento de Biología Cellular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile
| | - Rafaella V Zárate
- Departamento de Biología Cellular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile
| | - Benjamín P Valderrama
- Departamento de Biología Cellular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Science, University of Bristol, UK
| | - Jorge M Campusano
- Departamento de Biología Cellular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile.
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Association between olfactory sulcus morphology and olfactory functioning in schizophrenia and psychosis high-risk status. Heliyon 2019; 5:e02642. [PMID: 31667432 PMCID: PMC6812217 DOI: 10.1016/j.heliyon.2019.e02642] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/07/2019] [Accepted: 10/08/2019] [Indexed: 01/15/2023] Open
Abstract
Olfactory impairment has been reported in patients with schizophrenia and individuals with a high risk of psychosis, but its neural basis is largely unknown. We used magnetic resonance imaging to investigate the morphology of the olfactory sulcus (an indicator of olfactory system development) and its relation to olfactory function in 38 persons with an at-risk mental state (ARMS), 62 patients with schizophrenia, and 61 healthy controls. Odor detection and identification were examined with a T & T olfactometer. Compared with the controls, the olfactory sulcus was significantly shallower and odor identification was inferior among the ARMS and schizophrenia subjects. Across all subjects, but not within each group, the olfactory sulcus depth was significantly related to better identification of odors. Our results support the concept that olfactory sulcus morphology reflects the neurodevelopmental process of the olfactory system.
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8
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Abstract
Despite garnering minimal attention from the medical community overall, olfaction is indisputably critical in the manner in which we as humans interact with our surrounding environment. As the initial anatomical structure in the olfactory pathway, the nasal airway plays a crucial role in the transmission and perception of olfactory stimuli. The goal of this chapter is to provide a comprehensive overview of olfactory disturbances as it pertains to the sinonasal airway. This comprises an in-depth discussion of clinically relevant nasal olfactory anatomy and physiology, classification systems of olfactory disturbance, as well as the various etiologies and pathophysiologic mechanisms giving rise to this important disease entity. A systematic clinical approach to the diagnosis and clinical workup of olfactory disturbances is also provided in addition to an extensive review of the medical and surgical therapeutic modalities currently available.
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Affiliation(s)
- Joseph S. Schwartz
- Department of Otolaryngology—Head & Neck Surgery, McGill University, Montreal, QC, Canada
| | - Bobby A. Tajudeen
- Department of Otolaryngology—Head & Neck Surgery, Rush University, Chicago, IL, United States
| | - David W. Kennedy
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States,Correspondence to: David W. Kennedy, M.D., Department of Otorhinolaryngology—Head and Neck Surgery, Hospital of the University of Pennsylvania, 3400 Spruce St Ravdin 5, Philadelphia, PA 19104, United States. Tel: +1-215-662-6971, Fax: +1215-349-5977
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9
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Latent toxoplasmosis and olfactory functions of Rh positive and Rh negative subjects. PLoS One 2018; 13:e0209773. [PMID: 30589911 PMCID: PMC6307871 DOI: 10.1371/journal.pone.0209773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022] Open
Abstract
Backgrounds The prevalence of toxoplasmosis is higher in schizophrenics than in the general population. It has been suggested that certain symptoms of schizophrenia, including changes in olfactory functions, are in fact symptoms of toxoplasmosis that can be easily detected in schizophrenics only due to the increased prevalence of toxoplasmosis in this population. Schizophrenics have impaired identification of odors and lower sensitivity of odor detection, however, no information about these parameters of non-schizophrenic Toxoplasma-infected subjects is available. Methods Here we searched for differences in olfactory functions between 62 infected and 61 noninfected non-schizophrenic subjects using the case-controls experimental design. Results The infected men scored better than the non-infected controls in the standard odor-identification test. The infected women rated all smells as more intensive while the infected men rated nearly all smells as less intensive. Infected women rated the pleasantness of the smell of the cat urine as higher than the non-infected women and the opposite was true for the men–in contrast, higher pleasantness of odor in infected men and lower in infected women were observed and described in the 2011 study. Toxoplasmosis, Rh, and toxoplasmosis-Rh interaction were not associated with the rated pleasantness of the smell of other stimuli. However, our sample contained only 17 Rh negative men and 30 Rh negative women. Therefore, all results concerning the main effects of Rh factor and the interaction with Rh factor must be considered only preliminary. Conclusions Our results suggest that latent toxoplasmosis is associated with changes in the olfactory functions in humans; however, the observed changes differ from those observed in schizophrenics.
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Takahashi T, Nakamura M, Sasabayashi D, Komori Y, Higuchi Y, Nishikawa Y, Nishiyama S, Itoh H, Masaoka Y, Suzuki M. Olfactory deficits in individuals at risk for psychosis and patients with schizophrenia: relationship with socio-cognitive functions and symptom severity. Eur Arch Psychiatry Clin Neurosci 2018; 268:689-698. [PMID: 29071372 DOI: 10.1007/s00406-017-0845-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/19/2017] [Indexed: 01/18/2023]
Abstract
Odor identification deficits are well documented in patients with schizophrenia, but it remains unclear whether individuals at clinical high-risk for psychosis exhibit similar changes and whether their olfactory function is related to social/cognitive functions and symptomatology. In this study, we investigated odor detection sensitivity and identification ability in 32 individuals with at-risk mental state (ARMS), 59 schizophrenia patients, and 169 healthy controls using a T&T olfactometer. The ARMS and schizophrenia subjects were administered the Brief Assessment of Cognition in Schizophrenia (BACS), the Schizophrenia Cognition Rating Scale (SCoRS), and the Social and Occupational Functioning Assessment Scale (SOFAS) to assess their cognitive and social functions, and the Positive and Negative Syndrome Scale (PANSS) for clinical symptoms. Both the ARMS and schizophrenia subjects had lower odor identification ability when compared with healthy controls, while no significant difference was found in the odor detection sensitivity. The lower odor identification ability in the ARMS group correlated with the severity of negative symptoms and weakly correlated with lower performance on the BACS verbal fluency test. The olfactory measures of schizophrenia patients did not correlate with illness duration, medication, symptom severity, and social and cognitive functions. For the ARMS and schizophrenia groups, the olfactory measures did not correlate with the SOFAS and SCoRS scores. These findings suggest that high-risk subjects for psychosis already show odor identification deficits similar to those observed in schizophrenia patients, which probably reflect a biological trait related to vulnerability to psychosis.
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Affiliation(s)
- Tsutomu Takahashi
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Mihoko Nakamura
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Daiki Sasabayashi
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yuko Komori
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yuko Higuchi
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yumiko Nishikawa
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Shimako Nishiyama
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Hiroko Itoh
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yuri Masaoka
- Department of Physiology, Showa University School of Medicine, Tokyo, Japan
| | - Michio Suzuki
- Department of Neuropsychiatry University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama, 930-0194, Japan
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Negoias S, Pietsch K, Hummel T. Changes in olfactory bulb volume following lateralized olfactory training. Brain Imaging Behav 2018; 11:998-1005. [PMID: 27448159 DOI: 10.1007/s11682-016-9567-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Repeated exposure to odors modifies olfactory function. Consequently, "olfactory training" plays a significant role in hyposmia treatment. In addition, numerous studies show that the olfactory bulb (OB) volume changes in disorders associated with olfactory dysfunction. Aim of this study was to investigate whether and how olfactory bulb volume changes in relation to lateralized olfactory training in healthy people. Over a period of 4 months, 97 healthy participants (63 females and 34 males, mean age: 23.74 ± 4.16 years, age range: 19-43 years) performed olfactory training by exposing the same nostril twice a day to 4 odors (lemon, rose, eucalyptus and cloves) while closing the other nostril. Before and after olfactory training, magnetic resonance imaging (MRI) scans were performed to measure OB volume. Furthermore, participants underwent lateralized odor threshold and odor identification testing using the "Sniffin' Sticks" test battery.OB volume increased significantly after olfactory training (11.3 % and 13.1 % respectively) for both trained and untrained nostril. No significant effects of sex, duration and frequency of training or age of the subjects were seen. Interestingly, PEA odor thresholds worsened after training, while olfactory identification remained unchanged.These data show for the first time in humans that olfactory training may involve top-down process, which ultimately lead to a bilateral increase in olfactory bulb volume.
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Affiliation(s)
- S Negoias
- Smell & Taste Clinic, Department of Otorhinolaryngology, Head and Neck Surgery, Technical University Dresden, Fetscherstr. 74, 01307, Dresden, Germany. .,Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse, 3010, Bern, Switzerland.
| | - K Pietsch
- Smell & Taste Clinic, Department of Otorhinolaryngology, Head and Neck Surgery, Technical University Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - T Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, Head and Neck Surgery, Technical University Dresden, Fetscherstr. 74, 01307, Dresden, Germany
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Dong J, Wyss A, Yang J, Price TR, Nicolas A, Nalls M, Tranah G, Franceschini N, Xu Z, Schulte C, Alonso A, Cummings SR, Fornage M, Zaykin D, Li L, Huang X, Kritchevsky S, Liu Y, Gasser T, Wilson RS, De Jager PL, Singleton AB, Pinto JM, Harris T, Mosley TH, Bennett DA, London S, Yu L, Chen H. Genome-Wide Association Analysis of the Sense of Smell in U.S. Older Adults: Identification of Novel Risk Loci in African-Americans and European-Americans. Mol Neurobiol 2017; 54:8021-8032. [PMID: 27878761 PMCID: PMC5441979 DOI: 10.1007/s12035-016-0282-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 10/31/2016] [Indexed: 12/15/2022]
Abstract
The human sense of smell decreases with age, and a poor sense of smell are among the most important prodromal symptoms of several neurodegenerative diseases. Recent evidence further suggests a racial difference in the sense of smell among U.S. older adults. However, no genome-wide association study (GWAS) on the sense of smell has been conducted in African-Americans (AAs). We performed the first genome-wide meta-analysis of the sense of smell among 1979 AAs and 6582 European-Americans (EAs) from three U.S. aging cohorts. In the AA population, we identified nine novel regions (KLF4-ACTL7B, RAPGEF2-FSTL5, TCF4-LOC100505474, PCDH10, KIAA1751, MYO5B, MIR320B1-CD2, NR5A2-LINC00862, SALL1-C16orf97) that were associated with the sense of smell (P < 5 × 10-8). Many of these regions have been previously linked to neuropsychiatric (schizophrenia or epilepsy) or neurodegenerative (Parkinson's or Alzheimer's disease) diseases associated with a decreased sense of smell. In the EA population, we identified two novel loci in or near RASGRP1 and ANXA2P3 associated with sense of smell. In conclusion, this study identified several ancestry-specific loci that are associated with the sense of smell in older adults. While these findings need independent confirmation, they may lead to novel insights into the biology of the sense of smell in older adults and its relationships to neuropsychological and neurodegenerative diseases.
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Affiliation(s)
- Jing Dong
- Epidemiology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr. P.O. Box 12233, Mail drop A3-05, Research Triangle Park, NC, 27709, USA.
| | - Annah Wyss
- Epidemiology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr. P.O. Box 12233, Mail drop A3-05, Research Triangle Park, NC, 27709, USA
| | - Jingyun Yang
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - T Ryan Price
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD, USA
| | - Aude Nicolas
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD, USA
| | - Michael Nalls
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD, USA
| | - Greg Tranah
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
| | - Nora Franceschini
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC, USA
| | - Zongli Xu
- Epidemiology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr. P.O. Box 12233, Mail drop A3-05, Research Triangle Park, NC, 27709, USA
| | - Claudia Schulte
- Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Genome Biology for Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Alvaro Alonso
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Steven R Cummings
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
| | - Myriam Fornage
- Institute of Molecular Medicine and Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Dmitri Zaykin
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Leping Li
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Xuemei Huang
- Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Stephen Kritchevsky
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Yongmei Liu
- Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Thomas Gasser
- Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Genome Biology for Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Robert S Wilson
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Philip L De Jager
- Program in Translational Neuro Psychiatric Genomics, Institute for the Neurosciences, Departments of Neurology and Psychiatry, Brigham and Women's Hospital; Harvard Medical School; Program in Medical and Population Genetics, Broad Institute, Boston, MA, USA
| | - Andrew B Singleton
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD, USA
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, The University of Chicago Medicine and Biological Sciences, Chicago, IL, USA
| | - Tamara Harris
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, MD, USA
| | - Thomas H Mosley
- Division of Geriatrics, Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Stephanie London
- Epidemiology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr. P.O. Box 12233, Mail drop A3-05, Research Triangle Park, NC, 27709, USA
| | - Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Honglei Chen
- Epidemiology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr. P.O. Box 12233, Mail drop A3-05, Research Triangle Park, NC, 27709, USA
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Silveira-Moriyama L, Glass P, Rajan S, Carvalho R, Reis F, Penatti CAA, Muio V. The Hitchhiker's guide to the rhinencephalon. ARQUIVOS DE NEURO-PSIQUIATRIA 2016; 74:329-36. [PMID: 27097007 DOI: 10.1590/0004-282x20160043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 01/07/2016] [Indexed: 05/11/2023]
Abstract
Pathology of the rhinencephalon has been a subject of interest in the fields of neurodegenerative diseases, trauma, epilepsy and other neurological conditions. Most of what is known about the human rhinencephalon comes from comparative anatomy studies in other mammals and histological studies in primates. Functional imaging studies can provide new and important insight into the function of the rhinencephalon in humans but have limited spatial resolution, limiting its contribution to the study of the anatomy of the human rhinencephalon. In this study we aim to provide a brief and objective review of the anatomy of this important and often overlooked area of the nervous system.
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Affiliation(s)
| | - Philip Glass
- Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Suraj Rajan
- The Clinical Neuroscience Institute, Premier Health Miami Valley Hospital, Dayton, OH, USA
| | | | - Fabiano Reis
- Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | | | - Valeria Muio
- Universidade Nove de Julho, Sao Paulo, SP, Brazil
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Meijer JH, van Harten P, Meijer CJ, Koeter MW, Bruggeman R, Cahn W, Kahn RS, de Haan L. Association between olfactory identification and parkinsonism in patients with non-affective psychosis. Early Interv Psychiatry 2016; 10:404-10. [PMID: 25234230 DOI: 10.1111/eip.12183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 07/22/2014] [Indexed: 11/25/2022]
Abstract
AIM Olfactory identification deficits (OIDs) are seen in schizophrenia patients and individuals at increased risk for psychosis but its pathophysiology remains unclear. Although dopaminergic imbalance is known to lie at the core of schizophrenia symptomatology, its role in the development of OIDs has not been elucidated yet. This study investigated the association between OIDs and symptoms of parkinsonism as a derivative of dopaminergic functioning. METHODS In 320 patients diagnosed with non-affective psychosis, olfactory identification performance was assessed by means of the Sniffin' Sticks task. Level of parkinsonian symptoms was assessed by means of the Unified Parkinson's Disease Rating Scale (UPDRS-III). By means of multiple linear regression with bootstrapping, the association between UPDRS and Sniffin' Sticks score was investigated while correcting for potential confounders. A Bonferroni corrected P-value of 0.007 was used. RESULTS Higher UPDRS scores significantly predicted worse olfactory identification in patients with non-affective psychosis with an unadjusted b = -0.07 (95% CI -0.10 to -0.04) and an adjusted b = -0.04 (95% CI -0.07 to -0.01). CONCLUSION Results provide preliminary evidence that the same vulnerability may underlie the development of parkinsonism and OIDs in patients with non-affective psychosis. Further investigation should evaluate the clinical value of OIDs as a marker of dopaminergic vulnerability that may predict psychosis.
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Affiliation(s)
- Julia H Meijer
- Academic Medical Center, Academic Psychiatric Centre, Department of Early Psychosis, University of Amsterdam, Amsterdam, The Netherlands.
| | - Peter van Harten
- Psychiatric Centre GGZ Centraal, Amersfoort, The Netherlands.,Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University, Maastricht, The Netherlands
| | - Carin J Meijer
- Academic Medical Center, Academic Psychiatric Centre, Department of Early Psychosis, University of Amsterdam, Amsterdam, The Netherlands
| | - Maarten W Koeter
- Academic Medical Center, Academic Psychiatric Centre, Department of Early Psychosis, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard Bruggeman
- Department of Psychiatry and Rob Giel Research Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Wiepke Cahn
- Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands
| | - René S Kahn
- Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L de Haan
- Academic Medical Center, Academic Psychiatric Centre, Department of Early Psychosis, University of Amsterdam, Amsterdam, The Netherlands
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Affiliation(s)
- Anne Tromelin
- CNRS; UMR6265 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- INRA; UMR1324 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- Université de Bourgogne; UMR Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
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Lin A, Brewer WJ, Yung AR, Nelson B, Pantelis C, Wood SJ. Olfactory identification deficits at identification as ultra-high risk for psychosis are associated with poor functional outcome. Schizophr Res 2015; 161:156-62. [PMID: 25476117 DOI: 10.1016/j.schres.2014.10.051] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 10/27/2014] [Accepted: 10/27/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND We have previously reported that olfactory identification (OI) deficits are a promising premorbid marker of transition from ultra-high risk (UHR) to schizophrenia, but not to psychotic illness more generally. Whether this remains the case at longer follow-up, and whether there is decline in OI ability are unclear. METHOD The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 81 participants at baseline (identification of risk for psychosis) and 254 individuals at follow-up. Forty-nine participants underwent UPSIT assessment at both time points. UPSIT scores were investigated at an average of 7.08years after identification of risk in relation to transition to psychosis, a diagnosis of schizophrenia, and psychosocial/functional outcome. RESULTS UPSIT scores at baseline and follow-up did not differ between participants who transitioned to psychosis and those who did not. Similarly, there were no significant differences on UPSIT scores at baseline or follow-up between individuals with a diagnosis of schizophrenia and transitioned individuals without schizophrenia. Those with a poor functional outcome showed significantly lower baseline UPSIT scores than participants with good outcome. There was no significant association between functional outcome and follow-up UPSIT scores. There were no significant changes in UPSIT over time for any group. CONCLUSIONS These results suggest that impaired OI is not a good marker of the onset of psychosis and schizophrenia, but may differentiate UHR individuals who experience a poor functional outcome, regardless of transition status.
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Affiliation(s)
- A Lin
- Telethon Kids Institute, The University of Western Australia, Australia.
| | - W J Brewer
- Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Victoria, Australia
| | - A R Yung
- Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Victoria, Australia; Institute of Brain, Behaviour and Mental Health, University of Manchester, UK
| | - B Nelson
- Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Victoria, Australia
| | - C Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Victoria, Australia
| | - S J Wood
- Telethon Kids Institute, The University of Western Australia, Australia; Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Victoria, Australia
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Schoenfeld TJ, Cameron HA. Adult neurogenesis and mental illness. Neuropsychopharmacology 2015; 40:113-28. [PMID: 25178407 PMCID: PMC4262910 DOI: 10.1038/npp.2014.230] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 02/07/2023]
Abstract
Several lines of evidence suggest that adult neurogenesis, the production of new neurons in adulthood, may play a role in psychiatric disorders, including depression, anxiety, and schizophrenia. Medications and other treatments for mental disorders often promote the proliferation of new neurons; the time course for maturation and integration of new neurons in circuitry parallels the delayed efficacy of psychiatric therapies; adverse and beneficial experiences similarly affect development of mental illness and neurogenesis; and ablation of new neurons in adulthood alters the behavioral impact of drugs in animal models. At present, the links between adult neurogenesis and depression seem stronger than those suggesting a relationship between new neurons and anxiety or schizophrenia. Yet, even in the case of depression there is currently no direct evidence for a causative role. This article reviews the data relating adult neurogenesis to mental illness and discusses where research needs to head in the future.
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Affiliation(s)
- Timothy J Schoenfeld
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Heather A Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA,Section on Neuroplasticity, NIMH, 35 Convent Drive, Building 35/3C915, Bethesda, MD 20892-3718, USA, Tel: +1 301 496 3814, Fax: +1 301 480 4564, E-mail:
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Decrease in olfactory and taste receptor expression in the dorsolateral prefrontal cortex in chronic schizophrenia. J Psychiatr Res 2015; 60:109-16. [PMID: 25282281 DOI: 10.1016/j.jpsychires.2014.09.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/20/2014] [Accepted: 09/12/2014] [Indexed: 01/06/2023]
Abstract
We have recently identified up- or down-regulation of the olfactory (OR) and taste (TASR) chemoreceptors in the human cortex in several neurodegenerative diseases, raising the possibility of a general deregulation of these genes in neuropsychiatric disorders. In this study, we explore the possible deregulation of OR and TASR gene expression in the dorsolateral prefrontal cortex in schizophrenia. We used quantitative polymerase chain reaction on extracts from postmortem dorsolateral prefrontal cortex of subjects with chronic schizophrenia (n = 15) compared to control individuals (n = 14). Negative symptoms were evaluated premortem by the Positive and Negative Syndrome and the Clinical Global Impression Schizophrenia Scales. We report that ORs and TASRs are deregulated in the dorsolateral prefrontal cortex in schizophrenia. Seven out of eleven ORs and four out of six TASRs were down-regulated in schizophrenia, the most prominent changes of which were found in genes from the 11p15.4 locus. The expression did not associate with negative symptom clinical scores or the duration of the illness. However, most ORs and all TASRs inversely associated with the daily chlorpromazine dose. This study identifies for the first time a decrease in brain ORs and TASRs in schizophrenia, a neuropsychiatric disease not linked to abnormal protein aggregates, suggesting that the deregulation of these receptors is associated with altered cognition of these disorders. In addition, the influence of antipsychotics on the expression of ORs and TASRs in schizophrenia suggests that these receptors could be involved in the mechanism of action or side effects of antipsychotics.
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Příplatová L, Šebánková B, Flegr J. Contrasting effect of prepulse signals on performance of Toxoplasma-infected and Toxoplasma-free subjects in an acoustic reaction times test. PLoS One 2014; 9:e112771. [PMID: 25384036 PMCID: PMC4226587 DOI: 10.1371/journal.pone.0112771] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 10/16/2014] [Indexed: 11/20/2022] Open
Abstract
Background About 30% of people on Earth have latent toxoplasmosis. Infected subjects do not express any clinical symptoms, however, they carry dormant stages of parasite Toxoplasma for the rest of their life. This form of toxoplasmosis is mostly considered harmless, however, recent studies showed its specific effects on physiology, behaviour and its associations with various diseases, including psychiatric disorders such as schizophrenia. Individuals who suffer from schizophrenia have about 2.7 times higher prevalence of Toxoplasma-seropositivity than controls, which suggests that some traits characteristic of schizophrenic patients, including the sex difference in schizophrenia onset, decrease of grey matter density in specific brain areas and modification of prepulse inhibition of startle reaction could in fact be caused by toxoplasmosis for those patients who are Toxoplasma-seropositive. Methodology/Principal Findings We measured the effect of prepulse inhibition/facilitation of the startle reaction on reaction times. The students, 170 women and 66 men, were asked to react as quickly as possible to a startling acoustic signal by pressing a computer mouse button. Some of the startling signals were without the prepulse, some were 20 msec. preceded by a short (20 msec.) prepulse signal of lower intensity. Toxoplasma-seropositive subjects had longer reaction times than the controls. Acoustic prepulse shorted the reaction times in all subjects. This effect of prepulse on reaction times was stronger in male subjects and increased with the duration of infection, suggesting that it represented a cumulative effect of latent toxoplasmosis, rather than a fading out after effect of past acute toxoplasmosis. Conclusions Different sensitivity of Toxoplasma-seropositive and Toxoplasma-seronegative subjects on effect of prepulses on reaction times (the toxoplasmosis-prepulse interaction) suggested, but of course did not prove, that the alternations of prepulse inhibition of startle reaction observed in schizophrenia patients probably joined the list of schizophrenia symptoms that are in fact caused by latent toxoplasmosis.
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Affiliation(s)
- Lenka Příplatová
- Faculty of Science, Charles University, Dept. Philosophy and History of Science, Prague, Czech Republic
| | - Blanka Šebánková
- Faculty of Science, Charles University, Dept. Philosophy and History of Science, Prague, Czech Republic
| | - Jaroslav Flegr
- Faculty of Science, Charles University, Dept. Philosophy and History of Science, Prague, Czech Republic
- * E-mail:
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Maurage P, Rombaux P, de Timary P. Olfaction in alcohol-dependence: a neglected yet promising research field. Front Psychol 2014; 4:1007. [PMID: 24550850 PMCID: PMC3879530 DOI: 10.3389/fpsyg.2013.01007] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/17/2013] [Indexed: 11/13/2022] Open
Abstract
Olfaction research deeply renewed the knowledge of the pathophysiological mechanisms involved in various psychopathological states and showed that olfactory deficits might constitute an onset or trait marker in psychiatry. However, while alcohol-dependence is the most wide spread psychiatric disorder and while olfaction might be involved in its development and maintenance, olfactory abilities have been little explored in this population. The central aim of this paper is thus to underline the usefulness of olfaction research in alcohol-dependence. After reviewing the few olfaction studies available, a research agenda will be proposed, identifying the major challenges for future research, and particularly: (1) the identification of the origin, extent and cerebral correlates of olfaction deficits; (2) the links between olfaction and emotional-cognitive deficits, and the use of olfaction to understand the pathomechanisms of alcohol-dependence; (3) the interactions between olfaction and other sensory modalities; (4) the use of olfaction to predict the appearance and intensity of cognitive impairments; (5) the impact of olfaction deficits on everyday life in alcohol-dependence.
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Affiliation(s)
- Pierre Maurage
- Laboratory for Experimental Psychopathology, Psychological Sciences Research Institute, Université catholique de Louvain Louvain-la-Neuve, Belgium
| | - Philippe Rombaux
- Department of Otorhinolaryngology, St Luc Hospital and Institute of Neuroscience, Université catholique de Louvain Brussels, Belgium
| | - Philippe de Timary
- Laboratory for Experimental Psychopathology, Psychological Sciences Research Institute, Université catholique de Louvain Louvain-la-Neuve, Belgium ; Department of Adult Psychiatry, St Luc Hospital and Institute of Neuroscience, Université catholique de Louvain Brussels, Belgium
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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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Maurage P, Campanella S. Experimental and clinical usefulness of crossmodal paradigms in psychiatry: an illustration from emotional processing in alcohol-dependence. Front Hum Neurosci 2013; 7:394. [PMID: 23898250 PMCID: PMC3722513 DOI: 10.3389/fnhum.2013.00394] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/05/2013] [Indexed: 11/24/2022] Open
Abstract
Crossmodal processing (i.e., the construction of a unified representation stemming from distinct sensorial modalities inputs) constitutes a crucial ability in humans' everyday life. It has been extensively explored at cognitive and cerebral levels during the last decade among healthy controls. Paradoxically however, and while difficulties to perform this integrative process have been suggested in a large range of psychopathological states (e.g., schizophrenia and autism), these crossmodal paradigms have been very rarely used in the exploration of psychiatric populations. The main aim of the present paper is thus to underline the experimental and clinical usefulness of exploring crossmodal processes in psychiatry. We will illustrate this proposal by means of the recent data obtained in the crossmodal exploration of emotional alterations in alcohol-dependence. Indeed, emotional decoding impairments might have a role in the development and maintenance of alcohol-dependence, and have been extensively investigated by means of experiments using separated visual or auditory stimulations. Besides these unimodal explorations, we have recently conducted several studies using audio-visual crossmodal paradigms, which has allowed us to improve the ecological validity of the unimodal experimental designs and to offer new insights on the emotional alterations among alcohol-dependent individuals. We will show how these preliminary results can be extended to develop a coherent and ambitious research program using crossmodal designs in various psychiatric populations and sensory modalities. We will finally end the paper by underlining the various potential clinical applications and the fundamental implications that can be raised by this emerging project.
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Affiliation(s)
- Pierre Maurage
- Laboratory for Experimental Psychopathology, Faculty of Psychology, Institute of Psychology, Université Catholique de Louvain Louvain-la-Neuve, Belgium
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Kayser J, Tenke CE, Kroppmann CJ, Alschuler DM, Ben-David S, Fekri S, Bruder GE, Corcoran CM. Olfaction in the psychosis prodrome: electrophysiological and behavioral measures of odor detection. Int J Psychophysiol 2013; 90:190-206. [PMID: 23856353 DOI: 10.1016/j.ijpsycho.2013.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 07/03/2013] [Accepted: 07/05/2013] [Indexed: 10/26/2022]
Abstract
Smell identification deficits (SIDs) are relatively specific to schizophrenia and its negative symptoms, and may predict transition to psychosis in clinical high-risk (CHR) individuals. Moreover, event-related potentials (ERPs) to odors are reduced in schizophrenia. This study examined whether CHR patients show SIDs and abnormal olfactory N1 and P2 potentials. ERPs (49 channels) were recorded from 21 CHR and 20 healthy participants (13 males/group; ages 13-27 years) during an odor detection task using three concentrations of hydrogen sulfide (H2S) or blank air presented unilaterally by a constant-flow olfactometer. Neuronal generator patterns underlying olfactory ERPs were identified and measured by principal components analysis (unrestricted Varimax) of reference-free current source densities (CSD). Replicating previous findings, CSD waveforms to H2S stimuli were characterized by an early N1 sink (345 ms, lateral-temporal) and a late P2 source (600 ms, mid-frontocentroparietal). N1 and P2 varied monotonically with odor intensity (strong > medium > weak) and did not differ across groups. Patients and controls also showed comparable odor detection and had normal odor identification and thresholds (Sniffin' Sticks). However, olfactory ERPs strongly reflected differences in odor intensity and detection in controls, but these associations were substantially weaker in patients. Moreover, severity of negative symptoms in patients was associated with reduced olfactory ERPs and poorer odor detection, identification and thresholds. Three patients who developed psychosis had poorer odor detection and thresholds, and marked reductions of N1 and P2. Thus, despite the lack of overall group differences, olfactory measures may be of utility in predicting transition to psychosis among CHR patients.
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Affiliation(s)
- Jürgen Kayser
- Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, NY, USA; Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY, USA.
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Clepce M, Reich K, Gossler A, Kornhuber J, Thuerauf N. Olfactory perception in schizophrenia: the rating range for hedonic judgements is increased during acute episodes. Psychiatry Res 2013; 208:81-3. [PMID: 23089162 DOI: 10.1016/j.psychres.2012.09.052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 08/15/2012] [Accepted: 09/26/2012] [Indexed: 01/22/2023]
Abstract
Deficits in olfactory performance have been reported in schizophrenia but results on subjective odour ratings remain unclear. Compared to controls (N=34), schizophrenia inpatients (N=34) expressed deficits concerning odour threshold, discrimination and identification but intact intensity ratings. Most interestingly, patients showed an increased rating range concerning olfactory hedonic judgements.
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Affiliation(s)
- Marion Clepce
- Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Germany.
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Oh HK, Park SJ, Bae SG, Kim MJ, Jang JH, Ahn YJ, Woo H, Kwon G, Ryu JH. Kami-ondam-tang, a traditional herbal prescription, attenuates the prepulse inhibition deficits and cognitive impairments induced by MK-801 in mice. JOURNAL OF ETHNOPHARMACOLOGY 2013; 146:600-607. [PMID: 23376282 DOI: 10.1016/j.jep.2013.01.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Kami-ondam-tang (KODT) has been used to treat neuropsychiatric disorders, including neurosis and insomnia, in traditional herbal medicine. However, the mechanisms of this drug have not been well characterized in the treatment of schizophrenia-like behaviors. AIM OF THE STUDY We investigated whether schizophrenia-like behaviors induced by MK-801, a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, could be attenuated by KODT. MATERIALS AND METHODS Acute systemic administration of MK-801 was used to establish an animal model of schizophrenia. The effects of KODT on the MK-801-induced prepulse inhibition (PPI) deficits, hyperlocomotion, social withdrawal, and cognitive impairment were assessed. We also examined the changes in the expression levels of Akt and extracellular signal-regulated kinase (ERK) after the administration of KODT with MK-801 in the cortical and hippocampal tissues. RESULTS The acoustic startle response test showed that the acoustic startle enhancement and PPI deficits induced by MK-801 were attenuated by KODT. Moreover, KODT ameliorated social and objective recognition impairments that were induced by MK-801 in the social novelty preference test and the novel object recognition test. In addition, the upregulation of phosphorylated Akt or phosphorylated ERK expression induced by MK-801 was blocked by KODT in the cortex. However, MK-801-induced hyperlocomotion was not affected by KODT in the open field test. CONCLUSION These findings suggest that KODT attenuates MK-801-induced PPI disruption, social interaction deficits, and cognitive impairments, possibly, by regulating of cortical Akt and ERK signaling.
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Affiliation(s)
- Hee Kyong Oh
- Department of Oriental Pharmaceutical Science, Kyung Hee East-West Pharmaceutical Research Institute, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
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Drews E, Otte DM, Zimmer A. Involvement of the primate specific gene G72 in schizophrenia: From genetic studies to pathomechanisms. Neurosci Biobehav Rev 2012; 37:2410-7. [PMID: 23092656 DOI: 10.1016/j.neubiorev.2012.10.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 09/03/2012] [Accepted: 10/15/2012] [Indexed: 12/28/2022]
Abstract
Schizophrenia is a human mental disorder that affects an individual's thoughts, perception, affect and behavior, which is caused by a complex interaction of genetic and environmental factors. Genetic studies have implicated the evolutionary novel, anthropoid primate-specific gene locus G72/G30 in the etiology of schizophrenia and other psychiatric disorders. This gene encodes the protein LG72, which has been discussed as a modulator of the peroxisomal enzyme d-amino-acid-oxidase (DAO), or, alternatively as a mitochondrial protein. Recently, G72 transgenic (G72Tg) mice were generated that express the protein throughout the brain. These mice show several behavioral deficits that are related to schizophrenia. Further, G72Tg mice have a reduced activity of mitochondrial complex I, with a concomitantly increased production of reactive oxygen species, as well as deficits in short-term plasticity. Results from these studies demonstrate that expression of the human G72/G30 gene locus in mice produces behavioral phenotypes that are relevant to schizophrenia. They implicate LG72-induced mitochondrial and synaptic defects as a possible pathomechanism of this disease.
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Affiliation(s)
- Eva Drews
- Institute of Molecular Psychiatry, University of Bonn, Germany.
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Kjelvik G, Evensmoen HR, Brezova V, Håberg AK. The human brain representation of odor identification. J Neurophysiol 2012; 108:645-57. [PMID: 22539820 DOI: 10.1152/jn.01036.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Odor identification (OI) tests are increasingly used clinically as biomarkers for Alzheimer's disease and schizophrenia. The aim of this study was to directly compare the neuronal correlates to identified odors vs. nonidentified odors. Seventeen females with normal olfactory function underwent a functional magnetic resonance imaging (fMRI) experiment with postscanning assessment of spontaneous uncued OI. An event-related analysis was performed to compare within-subject activity to spontaneously identified vs. nonidentified odors at the whole brain level, and in anatomic and functional regions of interest (ROIs) in the medial temporal lobe (MTL). Parameter estimate values and blood oxygenated level-dependent (BOLD) signal curves for correctly identified and nonidentified odors were derived from functional ROIs in hippocampus, entorhinal, piriform, and orbitofrontal cortices. Number of activated voxels and max parameter estimate values were obtained from anatomic ROIs in the hippocampus and the entorhinal cortex. At the whole brain level the correct OI gave rise to increased activity in the left entorhinal cortex and secondary olfactory structures, including the orbitofrontal cortex. Increased activation was also observed in fusiform, primary visual, and auditory cortices, inferior frontal plus inferior temporal gyri. The anatomic MTL ROI analysis showed increased activation in the left entorhinal cortex, right hippocampus, and posterior parahippocampal gyri in correct OI. In the entorhinal cortex and hippocampus the BOLD signal increased specifically in response to identified odors and decreased for nonidentified odors. In orbitofrontal and piriform cortices both identified and nonidentified odors gave rise to an increased BOLD signal, but the response to identified odors was significantly greater than that for nonidentified odors. These results support a specific role for entorhinal cortex and hippocampus in OI, whereas piriform and orbitofrontal cortices are active in both smelling and OI. Moreover, episodic as well as semantic memory systems appeared to support OI.
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Affiliation(s)
- Grete Kjelvik
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
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Malaspina D, Goetz R, Keller A, Messinger JW, Bruder G, Goetz D, Opler M, Harlap S, Harkavy–Friedman J, Antonius D. Olfactory processing, sex effects and heterogeneity in schizophrenia. Schizophr Res 2012; 135:144-51. [PMID: 22177347 PMCID: PMC3288877 DOI: 10.1016/j.schres.2011.11.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 11/18/2011] [Accepted: 11/21/2011] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Smell identification deficits are associated with negative symptoms in schizophrenia, particularly in males. Far less information is known about the relationship of odor detection sensitivity (acuity) and negative symptoms in schizophrenia, and currently there is a dearth in sex-stratified research specifically examining odor sensitivity and smell identification. METHODS Fifty-eight individuals with schizophrenia and 42 healthy comparison subjects were assessed on tests of odor sensitivity, smell identification and cognition. Negative symptoms were assessed with the Positive and Negative Syndrome Scale and the Schedule for the Deficit Syndrome. RESULTS In healthy males, increased odor detection sensitivity predicted better smell identification scores. In contrast, male schizophrenia patients showed a significant inverse relationship, in which increased odor sensitivity predicted lower smell identification scores. Odor sensitivity and smell identification were unrelated in both schizophrenia and healthy females. Olfactory processing was strongly linked to negative symptoms, but the relationships differed by sex. Emotional expression deficits were related to odor detection hypersensitivity in female patients, whereas smell identification deficits predicted these emotional deficits in male cases. CONCLUSION Sex differences in olfactory functioning were identified in healthy subjects and in schizophrenia patients. Smell identification was related to negative symptoms in males with schizophrenia, whereas odor detection sensitivity predicted these features in females. Sex differences should be considered in future analyses that employ odor stimuli for neuropsychiatric research.
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Affiliation(s)
- Dolores Malaspina
- New York University School of Medicine, Institute for Social and Psychiatric Initiatives, 500 1st Avenue, NBV 22N10, New York, NY 10016, USA.
| | - Raymond Goetz
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA,New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA
| | - Andreas Keller
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA,The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Julie W Messinger
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA
| | - Gerard Bruder
- New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA
| | - Deborah Goetz
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA
| | - Mark Opler
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA
| | - Susan Harlap
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA
| | | | - Daniel Antonius
- New York University School of Medicine; Institute for Social and Psychiatric Initiatives (InSPIRES), 500 1st Avenue, NBV 22N10, New York, NY 10016, USA,University at Buffalo, State University of New York, Buffalo, New York
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Flegr J, Lenochová P, Hodný Z, Vondrová M. Fatal attraction phenomenon in humans: cat odour attractiveness increased for toxoplasma-infected men while decreased for infected women. PLoS Negl Trop Dis 2011; 5:e1389. [PMID: 22087345 PMCID: PMC3210761 DOI: 10.1371/journal.pntd.0001389] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/23/2011] [Indexed: 11/24/2022] Open
Abstract
Background Latent toxoplasmosis, a lifelong infection with the protozoan Toxoplasma gondii, has cumulative effects on the behaviour of hosts, including humans. The most impressive effect of toxoplasmosis is the “fatal attraction phenomenon,” the conversion of innate fear of cat odour into attraction to cat odour in infected rodents. While most behavioural effects of toxoplasmosis were confirmed also in humans, neither the fatal attraction phenomenon nor any toxoplasmosis-associated changes in olfactory functions have been searched for in them. Principal Findings Thirty-four Toxoplasma-infected and 134 noninfected students rated the odour of urine samples from cat, horse, tiger, brown hyena and dog for intensity and pleasantness. The raters were blind to their infection status and identity of the samples. No signs of changed sensitivity of olfaction were observed. However, we found a strong, gender dependent effect of toxoplasmosis on the pleasantness attributed to cat urine odour (p = 0.0025). Infected men rated this odour as more pleasant than did the noninfected men, while infected women rated the same odour as less pleasant than did noninfected women. Toxoplasmosis did not affect how subjects rated the pleasantness of any other animal species' urine odour; however, a non-significant trend in the same directions was observed for hyena urine. Conclusions The absence of the effects of toxoplasmosis on the odour pleasantness score attributed to large cats would suggest that the amino acid felinine could be responsible for the fatal attraction phenomenon. Our results also raise the possibility that the odour-specific threshold deficits observed in schizophrenia patients could be caused by increased prevalence of Toxoplasma-infected subjects in this population rather than by schizophrenia itself. The trend observed with the hyena urine sample suggests that this carnivore, and other representatives of the Feliformia suborder, should be studied for their possible role as definitive hosts in the life cycle of Toxoplasma. Latent toxoplasmosis, a lifelong infection with the protozoan Toxoplasma gondii, has cumulative effects on the behaviour of hosts, including humans. The most impressive effect of toxoplasmosis is the so-called “fatal attraction phenomenon,” the conversion of innate fear of odour of the definitive host, the cat, into attraction to cat odour in rodents infected with Toxoplasma. While most behavioural effects of Toxoplasma infection were confirmed also in humans, neither the fatal attraction phenomenon nor any toxoplasmosis-induced changes in olfactory functions have been searched for in them. Our study performed on 34 Toxoplasma-infected and 134 noninfected students showed that the infected men rated odour of cat urine as more pleasant than did the noninfected men, while infected women rated the same odour as less pleasant than did noninfected women. No significant effect of toxoplasmosis on the urine odour pleasantness was found for horse, tiger, brown hyena and dog. The possible absence of the effects of toxoplasmosis on the urine odour pleasantness score attributed to tiger would suggest that the amino acid felinine, which is absent in urine of large cats, could be responsible for the fatal attraction phenomenon.
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Affiliation(s)
- Jaroslav Flegr
- Department of Biology, Charles University, Prague, Czech Republic.
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Maurage P, Callot C, Philippot P, Rombaux P, de Timary P. Chemosensory event-related potentials in alcoholism: A specific impairment for olfactory function. Biol Psychol 2011; 88:28-36. [DOI: 10.1016/j.biopsycho.2011.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/05/2011] [Accepted: 06/13/2011] [Indexed: 11/24/2022]
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Maurage P, Callot C, Chang B, Philippot P, Rombaux P, de Timary P. Olfactory impairment is correlated with confabulation in alcoholism: towards a multimodal testing of orbitofrontal cortex. PLoS One 2011; 6:e23190. [PMID: 21858026 PMCID: PMC3155545 DOI: 10.1371/journal.pone.0023190] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 07/11/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Olfactory abilities are now a flourishing field in psychiatry research. As the orbitofrontal cortex appears to be simultaneously implicated in odour processing and executive impairments, it has been proposed that olfaction could constitute a cognitive marker of psychiatric states. While this assumption appears promising, very few studies have been conducted on this topic among psychopathological populations. The present study thus aimed at exploring the links between olfaction and executive functions. These links were evaluated using two tasks of comparable difficulty, one known to rely on orbitofrontal cortex processing (i.e., a confabulation task), and one not associated with this area (i.e., Stop-Signal task). METHODOLOGY/PRINCIPAL FINDINGS Twenty recently detoxified alcoholic individuals and twenty paired controls took part in an experiment evaluating olfactory abilities and executive functioning (i.e., Stop-Signal task and confabulation task). Comorbidities and potential biasing variables were also controlled for. Alcoholic individuals exhibited impaired performance for high-level olfactory processing and significant confabulation problems as compared to controls (but no deficit in Stop-Signal task), even when the influence of comorbidities was taken into account. Most importantly, olfactory abilities and confabulation rates were significantly correlated in both groups. CONCLUSIONS/SIGNIFICANCE Alcoholism jointly leads to olfactory and memory source impairments, and these two categories of deficits are associated. These results strongly support the proposition that olfactory and confabulation measures both index orbitofrontal functioning, and suggest that olfaction could become a reliable cognitive marker in psychiatric disorders. Moreover, it underlines the need to take into account these olfactory and source memory impairments in a clinical context.
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Affiliation(s)
- Pierre Maurage
- Neuroscience, Systems and Cognition (NEUROCS) Research Unit, Institute of Psychology, Catholic University of Louvain, Louvain-la-Neuve, Belgium.
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Wesson DW, Wilson DA. Sniffing out the contributions of the olfactory tubercle to the sense of smell: hedonics, sensory integration, and more? Neurosci Biobehav Rev 2010; 35:655-68. [PMID: 20800615 DOI: 10.1016/j.neubiorev.2010.08.004] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 08/17/2010] [Accepted: 08/18/2010] [Indexed: 11/28/2022]
Abstract
Since its designation in 1896 as a putative olfactory structure, the olfactory tubercle has received little attention in terms of elucidating its role in the processing and perception of odors. Instead, research on the olfactory tubercle has mostly focused on its relationship with the reward system. Here we provide a comprehensive review of research on the olfactory tubercle-with an emphasis on the likely role of this region in olfactory processing and its contributions to perception. Further, we propose several testable hypotheses regarding the likely involvement of the olfactory tubercle in both basic (odor detection, discrimination, parallel processing of olfactory information) and higher-order (social odor processing, hedonics, multi-modal integration) functions. Together, the information within this review highlights an understudied yet potentially critical component in central odor processing.
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Affiliation(s)
- Daniel W Wesson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
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