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Yu X, Wang X, Sakano H, Zorio DAR, Wang Y. Dynamics of the fragile X mental retardation protein correlates with cellular and synaptic properties in primary auditory neurons following afferent deprivation. J Comp Neurol 2020; 529:481-500. [PMID: 32449186 DOI: 10.1002/cne.24959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/26/2020] [Accepted: 05/14/2020] [Indexed: 01/01/2023]
Abstract
Afferent activity dynamically regulates neuronal properties and connectivity in the central nervous system. The Fragile X mental retardation protein (FMRP) is an RNA-binding protein that regulates cellular and synaptic properties in an activity-dependent manner. Whether and how FMRP level and localization are regulated by afferent input remains sparsely examined and how such regulation is associated with neuronal response to changes in sensory input is unknown. We characterized changes in FMRP level and localization in the chicken nucleus magnocellularis (NM), a primary cochlear nucleus, following afferent deprivation by unilateral cochlea removal. We observed rapid (within 2 hr) aggregation of FMRP immunoreactivity into large granular structures in a subset of deafferented NM neurons. Neurons that exhibited persistent FMRP aggregation at 12-24 hr eventually lost cytoplasmic Nissl substance, indicating cell death. A week later, FMRP expression in surviving neurons regained its homeostasis, with a slightly reduced immunostaining intensity and enhanced heterogeneity. Correlation analyses under the homeostatic status (7-14 days) revealed that neurons expressing relatively more FMRP had a higher capability of maintaining cell body size and ribosomal activity, as well as a better ability to detach inactive presynaptic terminals. Additionally, the intensity of an inhibitory postsynaptic protein, gephyrin, was reduced following deafferentation and was positively correlated with FMRP intensity, implicating an involvement of FMRP in synaptic dynamics in response to reduced afferent inputs. Collectively, this study demonstrates that afferent input regulates FMRP expression and localization in ways associated with multiple types of neuronal responses and synaptic rearrangements.
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Affiliation(s)
- Xiaoyan Yu
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
| | - Xiaoyu Wang
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA.,Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, China
| | - Hitomi Sakano
- Department of Otolaryngology, Bloedel Hearing Research Center, University of Washington, Seattle, Washington, USA.,Department of Otolaryngology, University of Rochester, Rochester, New York, USA
| | - Diego A R Zorio
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
| | - Yuan Wang
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
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2
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The observed alteration in BCL2 expression following lithium treatment is influenced by the choice of normalization method. Sci Rep 2018; 8:6399. [PMID: 29686228 PMCID: PMC5913222 DOI: 10.1038/s41598-018-24546-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 03/26/2018] [Indexed: 01/07/2023] Open
Abstract
Upregulation of B-cell CLL/lymphoma (BCL)2 expression following lithium treatment is seemingly well established and has been related to the neuroprotective property of the drug. However, while demonstrated by some (but not all) studies based on low-throughput techniques (e.g. qPCR) this effect is not reflected in high-throughput studies, such as microarrays and RNAseq. This manuscript presents a systematic review of currently available reports of lithium's effect on BCL2 expression. To our surprise, we found that the majority of the literature does not support the effect of lithium on BCL2 transcript or protein levels. Moreover, among the positive reports, several used therapeutically irrelevant lithium doses while others lack statistical power. We also noticed that numerous low-throughput studies normalized the signal using genes/proteins affected by lithium, imposing possible bias. Using wet bench experiments and reanalysis of publicly available microarray data, here we show that the reference gene chosen for normalization critically impacts the outcome of qPCR analyses of lithium's effect on BCL2 expression. Our findings suggest that experimental results might be severely affected by the choice of normalizing genes, and emphasize the need to re-evaluate stability of these genes in the context of the specific experimental conditions.
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Kamel NN, Ahmed AMH, Mehaisen GMK, Mashaly MM, Abass AO. Depression of leukocyte protein synthesis, immune function and growth performance induced by high environmental temperature in broiler chickens. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2017; 61:1637-1645. [PMID: 28455634 DOI: 10.1007/s00484-017-1342-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/08/2017] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
In tropical and semitropical regions, raising broiler chickens out of their thermal comfort zone can cause an added economic loss in the poultry industry. The cause for the deleterious effects on immunity and growth performance of broilers under high environmental temperatures is still poorly understood. Therefore, the aim of the current investigation was to evaluate the effect of heat stress on leukocytes protein synthesis and immune function as a possible direct cause of low performance in broiler chickens under such condition. In this study, 300 one-day-old male broiler chicks (Cobb500™) were randomly assigned into 2 groups with 5 replicates of 30 chicks each. From 21 to 42 days of age, one group was exposed to non-stressed condition at 24 °C and 50% relative humidity (control group), while the other group was exposed to heat stress at 35 °C and 50% relative humidity (HS group). At 42 days of age, blood samples were collected from each group to evaluate stress indicators, immune function, and leukocytes protein synthesis. Production performance was also recorded. Noteworthy, protein synthesis in leukocytes was significantly (P < 0.05) inhibited in HS group by 38% compared to control group. In contrast, the phosphorylation level on threonine 56 site (Thr56) of eukaryotic elongation factor (eEF2), which indicates the suppression of protein translation process through altering the protein elongation phase, was significantly threefold higher in HS group than in control (P < 0.05). In addition, an increase in stress indicators was markedly (P < 0.05) presented in the HS birds by twofold increase in heterophil/lymphocyte (H/L) ratio and threefold increase in plasma corticosterone level compared to control. Furthermore, the immune function was significantly (P < 0.05) suppressed in HS birds than control (0.99 vs. 1.88 mg/mL plasma IgG, 89.2 vs. 148.0 μg/mL plasma IgM, 4.80 vs. 7.20 antibody titer against SRBC, and 1.38 vs. 3.39 stimulation index of lymphocyte proliferation in HS vs. control group, respectively). Moreover, results on the broiler performance indicate that HS birds had a significant (P < 0.05) lower body weight gain by 58%, lower feed consumption by 39%, higher conversion ratio by 27%, and higher mortality by more than three times, compared to control birds. In conclusion, our results demonstrate that the inhibition of leukocyte protein synthesis through increasing the level of eEF2 Thr56 phosphorylation may play a key role in the observed decrease in immune function and growth performance with the high mortality rate encountered in broiler chickens under heat stress environment.
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Affiliation(s)
- Nancy N Kamel
- Department of Animal Production, National Research Centre, Giza, 12311, Egypt
| | - Ayman M H Ahmed
- Poultry Production Department, Faculty of Agriculture, Ain Shams University, 68 Hadayek Shobra, Cairo, 11241, Egypt
| | - Gamal M K Mehaisen
- Department of Animal Production, Faculty of Agriculture, Cairo University, 7 Gamaa Street, Giza, 12613, Egypt.
| | - Magdi M Mashaly
- Department of Animal Production, Faculty of Agriculture, Cairo University, 7 Gamaa Street, Giza, 12613, Egypt
| | - Ahmed O Abass
- Department of Animal Production, Faculty of Agriculture, Cairo University, 7 Gamaa Street, Giza, 12613, Egypt
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Sakano H, Zorio DAR, Wang X, Ting YS, Noble WS, MacCoss MJ, Rubel EW, Wang Y. Proteomic analyses of nucleus laminaris identified candidate targets of the fragile X mental retardation protein. J Comp Neurol 2017; 525:3341-3359. [PMID: 28685837 DOI: 10.1002/cne.24281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/23/2017] [Accepted: 07/04/2017] [Indexed: 12/17/2022]
Abstract
The avian nucleus laminaris (NL) is a brainstem nucleus necessary for binaural processing, analogous in structure and function to the mammalian medial superior olive. In chickens (Gallus gallus), NL is a well-studied model system for activity-dependent neural plasticity. Its neurons have bipolar extension of dendrites, which receive segregated inputs from two ears and display rapid and compartment-specific reorganization in response to unilateral changes in auditory input. More recently, fragile X mental retardation protein (FMRP), an RNA-binding protein that regulates local protein translation, has been shown to be enriched in NL dendrites, suggesting its potential role in the structural dynamics of these dendrites. To explore the molecular role of FMRP in this nucleus, we performed proteomic analysis of NL, using micro laser capture and liquid chromatography tandem mass spectrometry. We identified 657 proteins, greatly represented in pathways involved in mitochondria, translation and metabolism, consistent with high levels of activity of NL neurons. Of these, 94 are potential FMRP targets, by comparative analysis with previously proposed FMRP targets in mammals. These proteins are enriched in pathways involved in cellular growth, cellular trafficking and transmembrane transport. Immunocytochemistry verified the dendritic localization of several proteins in NL. Furthermore, we confirmed the direct interaction of FMRP with one candidate, RhoC, by in vitro RNA binding assays. In summary, we provide a database of highly expressed proteins in NL and in particular a list of potential FMRP targets, with the goal of facilitating molecular characterization of FMRP signaling in future studies.
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Affiliation(s)
- Hitomi Sakano
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, School of Medicine, Seattle, Washington
| | - Diego A R Zorio
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | - Xiaoyu Wang
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | - Ying S Ting
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - William S Noble
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, School of Medicine, Seattle, Washington
| | - Yuan Wang
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida.,Program in Neuroscience, Florida State University, Tallahassee, Florida
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Carroll BJ, Hyson RL. A role for inhibition in deafness-induced plasticity of the avian auditory brainstem. Neuroscience 2016; 327:10-9. [PMID: 27095711 DOI: 10.1016/j.neuroscience.2016.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 01/05/2023]
Abstract
To better understand the effects of deafness on the brain, these experiments examine how disrupted balance between excitatory and inhibitory neurotransmission following the loss of excitatory input from the auditory nerve alters the central auditory system. In the avian cochlear nucleus, nucleus magnocellularis (NM), deprivation of excitatory input induced by deafness triggers neuronal death. While this neuronal death was previously accredited to the loss of excitatory drive, the present experiments examine an alternative hypothesis: that inhibitory input to NM, which may also be affected by deafness, contributes to neuronal death in NM. Using an in vitro slice preparation in which excitatory input from the auditory nerve is absent, we pharmacologically altered GABA receptor activation in NM, and assayed an early marker of neuronal health, antigenicity for the ribosomal antibody Y10B (Y10B-ir). We found that GABA decreases Y10B-ir, and that GABAA activation is necessary for the GABA-induced effect. We further found that endogenous GABAA activation similarly decreases Y10B-ir and this decrease requires extracellular Ca(2+). Our results suggest that, in the absence of excitatory input, endogenous activation of ionotropic GABAA receptors is detrimental to NM neurons.
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Affiliation(s)
- Briana J Carroll
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - Richard L Hyson
- Department of Psychology, Florida State University, Tallahassee, FL, USA.
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Kral A, Kronenberger WG, Pisoni DB, O'Donoghue GM. Neurocognitive factors in sensory restoration of early deafness: a connectome model. Lancet Neurol 2016; 15:610-21. [PMID: 26976647 PMCID: PMC6260790 DOI: 10.1016/s1474-4422(16)00034-x] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/15/2015] [Accepted: 01/21/2016] [Indexed: 12/11/2022]
Abstract
Progress in biomedical technology (cochlear, vestibular, and retinal implants) has led to remarkable success in neurosensory restoration, particularly in the auditory system. However, outcomes vary considerably, even after accounting for comorbidity-for example, after cochlear implantation, some deaf children develop spoken language skills approaching those of their hearing peers, whereas other children fail to do so. Here, we review evidence that auditory deprivation has widespread effects on brain development, affecting the capacity to process information beyond the auditory system. After sensory loss and deafness, the brain's effective connectivity is altered within the auditory system, between sensory systems, and between the auditory system and centres serving higher order neurocognitive functions. As a result, congenital sensory loss could be thought of as a connectome disease, with interindividual variability in the brain's adaptation to sensory loss underpinning much of the observed variation in outcome of cochlear implantation. Different executive functions, sequential processing, and concept formation are at particular risk in deaf children. A battery of clinical tests can allow early identification of neurocognitive risk factors. Intervention strategies that address these impairments with a personalised approach, taking interindividual variations into account, will further improve outcomes.
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Affiliation(s)
- Andrej Kral
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinics, Medical University Hannover, Hannover, Germany; School of Behavioural and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA.
| | - William G Kronenberger
- Department of Psychiatry, and DeVault Otologic Research Laboratory, Department of Otolaryngology: Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Indianapolis, IN, USA
| | - David B Pisoni
- Department of Psychiatry, and DeVault Otologic Research Laboratory, Department of Otolaryngology: Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Indianapolis, IN, USA
| | - Gerard M O'Donoghue
- National Institute of Health Research, Nottingham Hearing Biomedical Research Unit, Nottingham University Hospitals NHS Trust, Nottingham, UK
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Call CL, Hyson RL. Activity-dependent regulation of calcium and ribosomes in the chick cochlear nucleus. Neuroscience 2016; 316:201-8. [PMID: 26739326 DOI: 10.1016/j.neuroscience.2015.12.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 01/25/2023]
Abstract
Cochlea removal results in the death of 20-30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM). Two potentially cytotoxic events, a dramatic rise in intracellular calcium concentration ([Ca(2+)]i) and a decline in the integrity of ribosomes are observed within 1h of deafferentation. Glutamatergic input from the auditory nerve has been shown to preserve NM neuron health by activating metabotropic glutamate receptors (mGluRs), maintaining both normal [Ca(2+)]i and ribosomal integrity. One interpretation of these results is that a common mGluR-activated signaling cascade is required for the maintenance of both [Ca(2+)]i and ribosomal integrity. This could happen if both responses are influenced directly by a common messenger, or if the loss of mGluR activation causes changes in one component that secondarily causes changes in the other. The present studies tested this common-mediator hypothesis in slice preparations by examining activity-dependent regulation of [Ca(2+)]i and ribosomes in the same tissue after selectively blocking group I mGluRs (1-Aminoindan-1,5-dicarboxylic acid (AIDA)) or group II mGluRs (LY 341495) during unilateral auditory nerve stimulation. Changes in [Ca(2+)]i of NM neurons were measured using fura-2 ratiometric calcium imaging and the tissue was subsequently processed for Y10B immunoreactivity (Y10B-ir), an antibody that recognizes a ribosomal epitope. The group I mGluR antagonist blocked the activity-dependent regulation of both [Ca(2+)]i and Y10B-ir, but the group II antagonist blocked only the activity-dependent regulation of Y10B-ir. That is, even when group II receptors were blocked, stimulation continued to maintain low [Ca(2+)]i, but it did not maintain Y10B-ir. These results suggest a dissociation in how calcium and ribosomes are regulated in NM neurons and that ribosomes can be regulated through a mechanism that is independent of calcium regulation.
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Affiliation(s)
- C L Call
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - R L Hyson
- Department of Psychology, Florida State University, Tallahassee, FL, USA.
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Wang Y, Sakano H, Beebe K, Brown MR, de Laat R, Bothwell M, Kulesza RJ, Rubel EW. Intense and specialized dendritic localization of the fragile X mental retardation protein in binaural brainstem neurons: a comparative study in the alligator, chicken, gerbil, and human. J Comp Neurol 2015; 522:2107-28. [PMID: 24318628 DOI: 10.1002/cne.23520] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 11/09/2022]
Abstract
Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders.
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Affiliation(s)
- Yuan Wang
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle, WA, 98195-7923
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Carzoli KL, Hyson RL. Activation of metabotropic glutamate receptors regulates ribosomes of cochlear nucleus neurons. PLoS One 2014; 9:e111243. [PMID: 25334004 PMCID: PMC4205043 DOI: 10.1371/journal.pone.0111243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 09/29/2014] [Indexed: 11/25/2022] Open
Abstract
The brain stem auditory system of the chick is an advantageous model for examining changes that occur as a result of deafness. Elimination of acoustic input through cochlear ablation results in the eventual death of approximately 30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM). One early change following deafness is an alteration in NM ribosomes, evidenced both by a decrease in protein synthesis and reduction in antigenicity for Y10B, a monoclonal antibody that recognizes a ribosomal epitope. Previous studies have shown that mGluR activation is necessary to maintain Y10B antigenicity and NM viability. What is still unclear, however, is whether or not mGluR activation is sufficient to prevent deafness-induced changes in these neurons, or if other activity-dependent factors are also necessary. The current study investigated the ability of mGluR activation to regulate cochlear nucleus ribosomes in the absence of auditory nerve input. In vitro methods were employed to periodically pressure eject glutamate or mGluR agonists over neurons on one side of a slice preparation leaving the opposite side of the same slice untreated. Immunohistochemistry was then performed using Y10B in order to assess ribosomal changes. Application of glutamate and both group I and II selective mGluR agonists effectively rescued ribosomal antigenicity on the treated side of the slice in comparison to ribosomes on the untreated side. These findings suggest that administration of mGluR agonists is sufficient to reduce the early interruption of normal ribosomal integrity that is typically seen following loss of auditory nerve activity.
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Affiliation(s)
- Kathryn L Carzoli
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, FL, United States of America
| | - Richard L Hyson
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, FL, United States of America
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