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Neophytou K, Williamson K, Herrmann O, Afthinos A, Gallegos J, Martin N, Tippett DC, Tsapkini K. Home-Based Transcranial Direct Current Stimulation in Primary Progressive Aphasia: A Pilot Study. Brain Sci 2024; 14:391. [PMID: 38672040 PMCID: PMC11048435 DOI: 10.3390/brainsci14040391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/12/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND This study aims to determine (a) if home-based anodal transcranial direct current stimulation (a-tDCS) delivered to the left supramarginal gyrus (SMG) coupled with verbal short-term memory/working memory (vSTM/WM) treatment ("RAM", short for "Repeat After Me") is more effective than sham-tDCS in improving vSTM/WM in patients with primary progressive aphasia (PPA), and (b) whether tDCS effects generalize to other language and cognitive abilities. METHODS Seven PPA participants received home-based a-tDCS and sham-tDCS coupled with RAM treatment in separate conditions in a double-blind design. The treatment task required participants to repeat word spans comprising semantically and phonologically unrelated words in the same and reverse order. The evaluation of treatment effects was carried out using the same tasks as in the treatment but with different items (near-transfer effects) and tasks that were not directly related to the treatment (far-transfer effects). RESULTS A-tDCS showed (a) a significant effect in improving vSTM abilities, measured by word span backward, and (b) a generalization of this effect to other language abilities, namely, spelling (both real words and pseudowords) and learning (retention and delayed recall). CONCLUSIONS These preliminary results indicate that vSTM/WM intervention can improve performance in trained vSTM/WM tasks in patients with PPA, especially when augmented with home-based tDCS over the left SMG.
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Affiliation(s)
- Kyriaki Neophytou
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
| | - Kelly Williamson
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
| | - Olivia Herrmann
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
| | - Alexandros Afthinos
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
- Cooper Medical School of Rowan University, Rowan University, 401 Broadway, Camden, NJ 08103, USA
| | - Jessica Gallegos
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
| | - Nadine Martin
- Department of Communication Sciences and Disorders, Temple University, 1701 N. 13th Street, Philadelphia, PA 19122, USA;
| | - Donna C. Tippett
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 174, Baltimore, MD 21287, USA
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Kyrana Tsapkini
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Phipps 488, Baltimore, MD 21287, USA; (K.N.); (K.W.); (O.H.); (A.A.); (J.G.); (D.C.T.)
- Department of Cognitive Science, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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2
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Sagi R, Taylor JSH, Neophytou K, Cohen T, Rapp B, Rastle K, Ben-Shachar M. White matter associations with spelling performance. Brain Struct Funct 2024:10.1007/s00429-024-02775-7. [PMID: 38528269 DOI: 10.1007/s00429-024-02775-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 02/12/2024] [Indexed: 03/27/2024]
Abstract
Multiple neurocognitive processes are involved in the highly complex task of producing written words. Yet, little is known about the neural pathways that support spelling in healthy adults. We assessed the associations between performance on a difficult spelling-to-dictation task and microstructural properties of language-related white matter pathways, in a sample of 73 native English-speaking neurotypical adults. Participants completed a diffusion magnetic resonance imaging scan and a cognitive assessment battery. Using constrained spherical deconvolution modeling and probabilistic tractography, we reconstructed dorsal and ventral white matter tracts of interest, bilaterally, in individual participants. Spelling associations were found in both dorsal and ventral stream pathways. In high-performing spellers, spelling scores significantly correlated with fractional anisotropy (FA) within the left inferior longitudinal fasciculus, a ventral stream pathway. In low-performing spellers, spelling scores significantly correlated with FA within the third branch of the right superior longitudinal fasciculus, a dorsal pathway. An automated analysis of spelling errors revealed that high- and low- performing spellers also differed in their error patterns, diverging primarily in terms of the orthographic distance between their errors and the correct spelling, compared to the phonological plausibility of their spelling responses. The results demonstrate the complexity of the neurocognitive architecture of spelling. The distinct white matter associations and error patterns detected in low- and high- performing spellers suggest that they rely on different cognitive processes, such that high-performing spellers rely more on lexical-orthographic representations, while low-performing spellers rely more on phoneme-to-grapheme conversion.
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Affiliation(s)
- Romi Sagi
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel.
| | - J S H Taylor
- Division of Psychology and Language Sciences, University College London, London, UK
| | - Kyriaki Neophytou
- Department of Cognitive Science, Johns Hopkins University, Baltimore, USA
- Department of Neurology, Johns Hopkins Medicine, Baltimore, USA
| | - Tamar Cohen
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, USA
| | - Kathleen Rastle
- Department of Psychology, Royal Holloway, University of London, London, UK
| | - Michal Ben-Shachar
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel.
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3
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Neophytou K, Wiley R, Litovsky C, Tsapkini K, Rapp B. The right hemisphere's capacity for language: evidence from primary progressive aphasia. Cereb Cortex 2023; 33:9971-9985. [PMID: 37522277 PMCID: PMC10502784 DOI: 10.1093/cercor/bhad258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023] Open
Abstract
The role of the right hemisphere (RH) in core language processes is still a matter of intense debate. Most of the relevant evidence has come from studies of gray matter, with relatively little research on RH white matter (WM) connectivity. Using Diffusion Tensor Imaging-based tractography, the current work examined the role of the two hemispheres in language processing in 33 individuals with Primary Progressive Aphasia (PPA), aiming to better characterize the contribution of the RH to language processing in the context of left hemisphere (LH) damage. The findings confirm the impact of PPA on the integrity of the WM language tracts in the LH. Additionally, an examination of the relationship between tract integrity and language behaviors provides robust evidence of the involvement of the WM language tracts of both hemispheres in language processing in PPA. Importantly, this study provides novel evidence of a unique contribution of the RH to language processing (i.e. a contribution independent from that of the language-dominant LH). Finally, we provide evidence that the RH contribution is specific to language processing rather than being domain general. These findings allow us to better characterize the role of RH in language processing, particularly in the context of LH damage.
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Affiliation(s)
- Kyriaki Neophytou
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, United States
| | - Robert Wiley
- Department of Psychology, University of North Carolina at Greensboro, Greensboro, NC, United States
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, United States
| | - Celia Litovsky
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, United States
| | - Kyrana Tsapkini
- Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, United States
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, United States
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, United States
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4
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Kutzer MAM, Gupta V, Neophytou K, Doublet V, Monteith KM, Vale PF. Intraspecific genetic variation in host vigour, viral load and disease tolerance during Drosophila C virus infection. Open Biol 2023; 13:230025. [PMID: 36854375 PMCID: PMC9974301 DOI: 10.1098/rsob.230025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Genetic variation for resistance and disease tolerance has been described in a range of species. In Drosophila melanogaster, genetic variation in mortality following systemic Drosophila C virus (DCV) infection is driven by large-effect polymorphisms in the restriction factor pastrel (pst). However, it is unclear if pst contributes to disease tolerance. We investigated systemic DCV challenges spanning nine orders of magnitude, in males and females of 10 Drosophila Genetic Reference Panel lines carrying either a susceptible (S) or resistant (R) pst allele. We find among-line variation in fly survival, viral load and disease tolerance measured both as the ability to maintain survival (mortality tolerance) and reproduction (fecundity tolerance). We further uncover novel effects of pst on host vigour, as flies carrying the R allele exhibited higher survival and fecundity even in the absence of infection. Finally, we found significant genetic variation in the expression of the JAK-STAT ligand upd3 and the epigenetic regulator of JAK-STAT G9a. However, while G9a has been previously shown to mediate tolerance of DCV infection, we found no correlation between the expression of either upd3 or G9a on fly tolerance or resistance. Our work highlights the importance of both resistance and tolerance in viral defence.
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Affiliation(s)
- Megan A. M. Kutzer
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Vanika Gupta
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, UK
| | - Vincent Doublet
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Katy M. Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
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5
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White R, Sotillo J, Ancarola ME, Borup A, Boysen AT, Brindley PJ, Buzás EI, Cavallero S, Chaiyadet S, Chalmers IW, Cucher MA, Dagenais M, Davis CN, Devaney E, Duque‐Correa MA, Eichenberger RM, Fontenla S, Gasan TA, Hokke CH, Kosanovic M, Kuipers ME, Laha T, Loukas A, Maizels RM, Marcilla A, Mazanec H, Morphew RM, Neophytou K, Nguyen LT, Nolte‐‘t Hoen E, Povelones M, Robinson MW, Rojas A, Schabussova I, Smits HH, Sungpradit S, Tritten L, Whitehead B, Zakeri A, Nejsum P, Buck AH, Hoffmann KF. Special considerations for studies of extracellular vesicles from parasitic helminths: A community-led roadmap to increase rigour and reproducibility. J Extracell Vesicles 2023; 12:e12298. [PMID: 36604533 PMCID: PMC9816087 DOI: 10.1002/jev2.12298] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 12/12/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
Over the last decade, research interest in defining how extracellular vesicles (EVs) shape cross-species communication has grown rapidly. Parasitic helminths, worm species found in the phyla Nematoda and Platyhelminthes, are well-recognised manipulators of host immune function and physiology. Emerging evidence supports a role for helminth-derived EVs in these processes and highlights EVs as an important participant in cross-phylum communication. While the mammalian EV field is guided by a community-agreed framework for studying EVs derived from model organisms or cell systems [e.g., Minimal Information for Studies of Extracellular Vesicles (MISEV)], the helminth community requires a supplementary set of principles due to the additional challenges that accompany working with such divergent organisms. These challenges include, but are not limited to, generating sufficient quantities of EVs for descriptive or functional studies, defining pan-helminth EV markers, genetically modifying these organisms, and identifying rigorous methodologies for in vitro and in vivo studies. Here, we outline best practices for those investigating the biology of helminth-derived EVs to complement the MISEV guidelines. We summarise community-agreed standards for studying EVs derived from this broad set of non-model organisms, raise awareness of issues associated with helminth EVs and provide future perspectives for how progress in the field will be achieved.
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6
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Themistocleous C, Neophytou K, Rapp B, Tsapkini K. A Tool for Automatic Scoring of Spelling Performance. J Speech Lang Hear Res 2020; 63:4179-4192. [PMID: 33151810 PMCID: PMC8608207 DOI: 10.1044/2020_jslhr-20-00177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/22/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Purpose The evaluation of spelling performance in aphasia reveals deficits in written language and can facilitate the design of targeted writing treatments. Nevertheless, manual scoring of spelling performance is time-consuming, laborious, and error prone. We propose a novel method based on the use of distance metrics to automatically score spelling. This study compares six automatic distance metrics to identify the metric that best corresponds to the gold standard-manual scoring-using data from manually obtained spelling scores from individuals with primary progressive aphasia. Method Three thousand five hundred forty word and nonword spelling productions from 42 individuals with primary progressive aphasia were scored manually. The gold standard-the manual scores-were compared to scores from six automated distance metrics: sequence matcher ratio, Damerau-Levenshtein distance, normalized Damerau-Levenshtein distance, Jaccard distance, Masi distance, and Jaro-Winkler similarity distance. We evaluated each distance metric based on its correlation with the manual spelling score. Results All automatic distance scores had high correlation with the manual method for both words and nonwords. The normalized Damerau-Levenshtein distance provided the highest correlation with the manual scoring for both words (rs = .99) and nonwords (rs = .95). Conclusions The high correlation between the automated and manual methods suggests that automatic spelling scoring constitutes a quick and objective approach that can reliably substitute the existing manual and time-consuming spelling scoring process, an important asset for both researchers and clinicians.
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Affiliation(s)
| | - Kyriaki Neophytou
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD
- Department of Psychological & Brain Sciences, Johns Hopkins University, Baltimore, MD
| | - Kyrana Tsapkini
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD
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7
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Chow FWN, Koutsovoulos G, Ovando-Vázquez C, Neophytou K, Bermúdez-Barrientos JR, Laetsch DR, Robertson E, Kumar S, Claycomb JM, Blaxter M, Abreu-Goodger C, Buck AH. Secretion of an Argonaute protein by a parasitic nematode and the evolution of its siRNA guides. Nucleic Acids Res 2019; 47:3594-3606. [PMID: 30820541 PMCID: PMC6468290 DOI: 10.1093/nar/gkz142] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/16/2019] [Accepted: 02/25/2019] [Indexed: 12/18/2022] Open
Abstract
Extracellular RNA has been proposed to mediate communication between cells and organisms however relatively little is understood regarding how specific sequences are selected for export. Here, we describe a specific Argonaute protein (exWAGO) that is secreted in extracellular vesicles (EVs) released by the gastrointestinal nematode Heligmosomoides bakeri, at multiple copies per EV. Phylogenetic and gene expression analyses demonstrate exWAGO orthologues are highly conserved and abundantly expressed in related parasites but highly diverged in free-living genus Caenorhabditis. We show that the most abundant small RNAs released from the nematode parasite are not microRNAs as previously thought, but rather secondary small interfering RNAs (siRNAs) that are produced by RNA-dependent RNA Polymerases. The siRNAs that are released in EVs have distinct evolutionary properties compared to those resident in free-living or parasitic nematodes. Immunoprecipitation of exWAGO demonstrates that it specifically associates with siRNAs from transposons and newly evolved repetitive elements that are packaged in EVs and released into the host environment. Together this work demonstrates molecular and evolutionary selectivity in the small RNA sequences that are released in EVs into the host environment and identifies a novel Argonaute protein as the mediator of this.
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Affiliation(s)
- Franklin Wang-Ngai Chow
- Institute of Immunology and Infection Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Georgios Koutsovoulos
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Cesaré Ovando-Vázquez
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato 36824, México
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Jose R Bermúdez-Barrientos
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato 36824, México
| | - Dominik R Laetsch
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Elaine Robertson
- Institute of Immunology and Infection Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Sujai Kumar
- Institute of Immunology and Infection Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Mark Blaxter
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK.,Centre for Immunity, Infection and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Cei Abreu-Goodger
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Guanajuato 36824, México
| | - Amy H Buck
- Institute of Immunology and Infection Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK.,Centre for Immunity, Infection and Evolution, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JT, UK
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8
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Stockall L, Manouilidou C, Gwilliams L, Neophytou K, Marantz A. Prefix Stripping Re-Re-Revisited: MEG Investigations of Morphological Decomposition and Recomposition. Front Psychol 2019; 10:1964. [PMID: 31551860 PMCID: PMC6743348 DOI: 10.3389/fpsyg.2019.01964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/09/2019] [Indexed: 11/25/2022] Open
Abstract
We revisit a long-standing question in the psycholinguistic and neurolinguistic literature on comprehending morphologically complex words: are prefixes and suffixes processed using the same cognitive mechanisms? Recent work using Magnetoencephalography (MEG) to uncover the dynamic temporal and spatial responses evoked by visually presented complex suffixed single words provide us with a comprehensive picture of morphological processing in the brain, from early, form-based decomposition, through lexical access, grammatically constrained recomposition, and semantic interpretation. In the present study, we find that MEG responses to prefixed words reveal interesting early differences in the lateralization of the form-based decomposition response compared to the effects reported in the literature for suffixed words, but a very similar post-decomposition profile. These results not only address a question stretching back to the earliest days of modern psycholinguistics, but also add critical support and nuance to our much newer emerging understanding of spatial organization and temporal dynamics of morphological processing in the human brain.
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Affiliation(s)
- Linnaea Stockall
- Department of Linguistics, Queen Mary University of London, London, United Kingdom
| | - Christina Manouilidou
- Department of Comparative and General Linguistics, University of Ljubljana, Ljubljana, Slovenia
| | - Laura Gwilliams
- Department of Psychology, New York University, New York, NY, United States.,New York University Abu Dhabi Institute, New York University, Abu Dhabi, United Arab Emirates
| | - Kyriaki Neophytou
- New York University Abu Dhabi Institute, New York University, Abu Dhabi, United Arab Emirates.,Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, United States
| | - Alec Marantz
- Department of Psychology, New York University, New York, NY, United States.,New York University Abu Dhabi Institute, New York University, Abu Dhabi, United Arab Emirates.,Department of Linguistics, New York University, New York, NY, United States
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9
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Neophytou K, Wiley RW, Rapp B, Tsapkini K. The use of spelling for variant classification in primary progressive aphasia: Theoretical and practical implications. Neuropsychologia 2019; 133:107157. [PMID: 31401078 PMCID: PMC6817413 DOI: 10.1016/j.neuropsychologia.2019.107157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/16/2019] [Accepted: 08/05/2019] [Indexed: 11/29/2022]
Abstract
Currently, variant subtyping in primary progressive aphasia (PPA)
requires an expert neurologist and extensive language and cognitive testing.
Spelling impairments appear early in the development of the disorder, and the
three PPA variants (non-fluent - nfvPPA; semantic - svPPA; logopenic - lvPPA)
reportedly show fairly distinct spelling profiles. Given the theoretical and
empirical evidence indicating that spelling may serve as a proxy for spoken
language, the current study aimed to determine whether spelling performance
alone, when evaluated with advanced statistical analyses, allows for accurate
PPA variant classification. A spelling to dictation task (with real words and
pseudowords) was administered to 33 PPA individuals: 17 lvPPA, 10 nfvPPA, 6
svPPA. Using machine learning classification algorithms, we obtained pairwise
variant classification accuracies that ranged between 67 and 100%. In additional
analyses that assumed no prior knowledge of each case's variant,
classification accuracies ranged between 59 and 70%. To our knowledge, this is
the first time that all the PPA variants, including the most challenging
logopenic variant, have been classified with such high accuracy when using
information from a single language task. These results underscore the rich
structure of the spelling process and support the use of a spelling task in PPA
variant classification.
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Affiliation(s)
- Kyriaki Neophytou
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA.
| | - Robert W Wiley
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA; Department of Psychology, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA
| | - Kyrana Tsapkini
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA; Department of Neurology, Johns Hopkins Medicine, Baltimore, MD, USA
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10
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Chiweshe SM, Steketee PC, Jayaraman S, Paxton E, Neophytou K, Erasmus H, Labuschagne M, Cooper A, MacLeod A, Grey FE, Morrison LJ. Parasite specific 7SL-derived small RNA is an effective target for diagnosis of active trypanosomiasis infection. PLoS Negl Trop Dis 2019; 13:e0007189. [PMID: 30779758 PMCID: PMC6413958 DOI: 10.1371/journal.pntd.0007189] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/12/2019] [Accepted: 01/25/2019] [Indexed: 12/19/2022] Open
Abstract
Human and animal African trypanosomiasis (HAT & AAT, respectively) remain a significant health and economic issue across much of sub-Saharan Africa. Effective control of AAT and potential eradication of HAT requires affordable, sensitive and specific diagnostic tests that can be used in the field. Small RNAs in the blood or serum are attractive disease biomarkers due to their stability, accessibility and available technologies for detection. Using RNAseq, we have identified a trypanosome specific small RNA to be present at high levels in the serum of infected cattle. The small RNA is derived from the non-coding 7SL RNA of the peptide signal recognition particle and is detected in the serum of infected cattle at significantly higher levels than in the parasite, suggesting active processing and secretion. We show effective detection of the small RNA in the serum of infected cattle using a custom RT-qPCR assay. Strikingly, the RNA can be detected before microscopy detection of parasitaemia in the blood, and it can also be detected during remission periods of infection when no parasitaemia is detectable by microscopy. However, RNA levels drop following treatment with trypanocides, demonstrating accurate prediction of active infection. While the small RNA sequence is conserved between different species of trypanosome, nucleotide differences within the sequence allow generation of highly specific assays that can distinguish between infections with Trypanosoma brucei, Trypanosoma congolense and Trypanosoma vivax. Finally, we demonstrate effective detection of the small RNA directly from serum, without the need for pre-processing, with a single step RT-qPCR assay. Our findings identify a species-specific trypanosome small RNA that can be detected at high levels in the serum of cattle with active parasite infections. This provides the basis for the development of a cheap, non-invasive and highly effective diagnostic test for trypanosomiasis. African trypanosomes cause significant disease in humans and animals across sub-Saharan Africa. For both human and animal infections diagnostics that can accurately identify an active infection are lacking–this is particularly the case in animal disease where most diagnosis is based upon clinical signs, which is not a specific or sensitive means of detecting infection. There is therefore a significant unmet need for a pathogen marker of active infection that accurately indicates whether an animal or human is currently infected. Through analysing the blood of cattle infected with trypanosomes, we identified a short sequence of RNA that was present at very high levels. This small RNA derives from the trypanosome genome, and we could identify its presence in the genome of all three species that are responsible for human and animal disease. We were able to design species-specific tests, and showed that in samples from infected animals the assays were more sensitive than the traditional microscope-based detection, importantly the signal disappeared relatively quickly after successful treatment, and when treatment failed, the assay was able to accurately identify when infection persisted. We also demonstrated that the causative agent of human trypanosomiasis secretes the marker at similar levels to that seen in the animal-infective trypanosomes. Therefore, we have discovered a marker of trypanosome infection that is present at high levels in the blood of infected animals, disappears quickly upon successful treatment, but is effective at detecting instances of unsuccessful treatment and persistent infection. This represents a potentially powerful diagnostic tool for human and animal trypanosomiasis.
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Affiliation(s)
- Stephen M Chiweshe
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Pieter C Steketee
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Siddharth Jayaraman
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Edith Paxton
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Heidi Erasmus
- Clinvet Research Innovation, Uitzich Road, Bainsvlei, Bloemfontein, South Africa
| | - Michel Labuschagne
- Clinvet Research Innovation, Uitzich Road, Bainsvlei, Bloemfontein, South Africa
| | - Anneli Cooper
- Wellcome Centre for Molecular Parasitology, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, Bearsden Road, University of Glasgow, Glasgow, United Kingdom
| | - Annette MacLeod
- Wellcome Centre for Molecular Parasitology, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary & Life Sciences, Bearsden Road, University of Glasgow, Glasgow, United Kingdom
| | - Finn E Grey
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
| | - Liam J Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
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11
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Neophytou K, Faria A, Ficek B, Rapp B, Tsapkini K. White matter integrity is associated with impairments in distinct spelling mechanisms: Evidence from primary progressive aphasia. Front Hum Neurosci 2019. [DOI: 10.3389/conf.fnhum.2019.01.00119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Neophytou K, Manouilidou C, Stockall L, Marantz A. Syntactic and semantic restrictions on morphological recomposition: MEG evidence from Greek. Brain Lang 2018; 183:11-20. [PMID: 29778061 DOI: 10.1016/j.bandl.2018.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 04/12/2018] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Complex morphological processing has been extensively studied in the past decades. However, most of this work has either focused on only certain steps involved in this process, or it has been conducted on a few languages, like English. The purpose of the present study is to investigate the spatiotemporal cortical processing profile of the distinct steps previously reported in the literature, from decomposition to re-composition of morphologically complex items, in a relatively understudied language, Greek. Using magnetoencephalography, we confirm the role of the fusiform gyrus in early, form-based morphological decomposition, we relate the syntactic licensing of stem-suffix combinations to the ventral visual processing stream, somewhat independent from lexical access for the stem, and we further elucidate the role of orbitofrontal regions in semantic composition. Thus, the current study offers the most comprehensive test to date of visual morphological processing and additional, crosslinguistic validation of the steps involved in it.
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Affiliation(s)
- K Neophytou
- NYUAD Institute, New York University Abu Dhabi, United Arab Emirates.
| | - C Manouilidou
- Department of Comparative and General Linguistics, University of Ljubljana, Slovenia
| | - L Stockall
- Department of Linguistics, Queen Mary University of London, United Kingdom; NYUAD Institute, New York University Abu Dhabi, United Arab Emirates
| | - A Marantz
- NYUAD Institute, New York University Abu Dhabi, United Arab Emirates; Department of Psychology, New York University, USA; Department of Linguistics, New York University, USA
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13
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Neophytou K, Themistocleous C, Wiley R, Tsapkini K, Rapp B. Understanding and classifying the different variants of Primary Progressive Aphasia based on spelling performance. Front Hum Neurosci 2018. [DOI: 10.3389/conf.fnhum.2018.228.00001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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14
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Oltra-Massuet I, Sharpe V, Neophytou K, Marantz A. Syntactic Priming As a Test of Argument Structure: A Self-paced Reading Experiment. Front Psychol 2017; 8:1311. [PMID: 28861010 PMCID: PMC5559723 DOI: 10.3389/fpsyg.2017.01311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/17/2017] [Indexed: 12/02/2022] Open
Abstract
Using data from a behavioral structural priming experiment, we test two competing theoretical approaches to argument structure, which attribute different configurations to (in)transitive structures. These approaches make different claims about the relationship between unergatives and transitive structures selecting either a DP complement or a small clause complement in structurally unambiguous sentences, thus making different predictions about priming relations between them. Using statistical tools that combine a factorial 6 × 6 within subjects ANOVA, a mixed effects ANCOVA and a linear mixed effects regression model, we report syntactic priming effects in comprehension, which suggest a stronger predictive contribution of a model that supports an interpretive semantics view of syntax, whereby syntactic structures do not necessarily reflect argument/event structure in semantically unambiguous configurations. They also contribute novel experimental evidence that correlate representational complexity with language processing in the mind and brain. Our study further upholds the validity of combining quantitative methods and theoretical approaches to linguistics for advancing our knowledge of syntactic phenomena.
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Affiliation(s)
- Isabel Oltra-Massuet
- Department of English and German Studies, Rovira i Virgili UniversityTarragona, Spain.,Neuroscience of Language Lab, NYU Abu Dhabi Research Institute, New York University Abu DhabiAbu Dhabi, United Arab Emirates.,Serra Húnter Programme, Generalitat de CatalunyaBarcelona, Spain
| | - Victoria Sharpe
- Neuroscience of Language Lab, Departments of Linguistics and Psychology, New York UniversityNew York, NY, United States
| | - Kyriaki Neophytou
- Neuroscience of Language Lab, NYU Abu Dhabi Research Institute, New York University Abu DhabiAbu Dhabi, United Arab Emirates
| | - Alec Marantz
- Neuroscience of Language Lab, NYU Abu Dhabi Research Institute, New York University Abu DhabiAbu Dhabi, United Arab Emirates.,Neuroscience of Language Lab, Departments of Linguistics and Psychology, New York UniversityNew York, NY, United States
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