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Taylor MJ, van Leeuwen TM, Kuja-Halkola R, Lundström S, Larsson H, Lichtenstein P, Bölte S, Neufeld J. Genetic and environmental architecture of synaesthesia and its association with the autism spectrum-a twin study. Proc Biol Sci 2023; 290:20231888. [PMID: 37876199 PMCID: PMC10598415 DOI: 10.1098/rspb.2023.1888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 09/26/2023] [Indexed: 10/26/2023] Open
Abstract
Synaesthesia is a sensory phenomenon where external stimuli, such as sounds or letters, trigger additional sensations (e.g. colours). Synaesthesia aggregates in families but its heritability is unknown. The phenomenon is more common in people on the autism spectrum compared with the general population and associated with higher autistic traits. Using classical twin design, we assessed the heritability of individual differences in self-reported synaesthesia and the genetic and environmental contributions to their association with autistic traits within a population twin cohort (n = 4262, age = 18 years). We estimated individual differences in synaesthesia to be heritable and influenced by environmental factors not shared between twins. The association between individual differences in synaesthesia and autistic traits was estimated to be predominantly under genetic influence and seemed to be mainly driven by non-social autistic traits (repetitive behaviours, restricted interests and attention to detail). Our study suggests that the link between synaesthesia and autism might reside in shared genetic causes, related to non-social autistic traits such as alterations in perception. Future studies building on these findings may attempt to identify specific groups of genes that influence both autism, synaesthesia and perception.
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Affiliation(s)
- Mark J. Taylor
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Tessa M. van Leeuwen
- Tilburg School of Humanities and Digital Sciences, Department of Communication and Cognition, Tilburg University, 5037 AB Tilburg, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 XZ Nijmegen, The Netherlands
| | - Ralf Kuja-Halkola
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Sebastian Lundström
- Gillberg Neuropsychiatry Centre, Centre for Ethics, Law and Mental Health, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Henrik Larsson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 17165 Stockholm, Sweden
- School of Medical Sciences, Örebro University, 70281 Örebro, Sweden
| | - Paul Lichtenstein
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Sven Bölte
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, 11364 Stockholm, Sweden
- Curtin Autism Research Group, Curtin School of Allied Health, Curtin University, WA 66102 Perth, Western Australia
- Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, 11364 Stockholm, Sweden
| | - Janina Neufeld
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, 11364 Stockholm, Sweden
- Swedish Collegium for Advanced Study (SCAS), 75238 Uppsala, Sweden
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Abstract
INTRODUCTION This study determines whether there is a familial aggregation between synaesthesia and two neuropsychiatric conditions (autism and schizophrenia). METHOD We examined the prevalence of autism and schizophrenia among synaesthetes and non-synaesthetic controls, and among their first-degree relatives. RESULTS As predicted, autism occurred at elevated levels among synaesthetes and-we document for the first time-amongst their relatives. This was not found for schizophrenia, where a link may be expected, or in a control condition (type 1 diabetes) where we had no a priori reason to assume a link. Synaesthetes, compared to controls, were also more likely to have other synaesthetes in their family. People with three or more types of synaesthesia were more likely (compared to synaesthetes with fewer types) to have synaesthetic relatives and to report autism in themselves. People with two or more types of synaesthesia (compared to synaesthetes with only one type) were more likely to report familial autism. CONCLUSIONS The results suggest a shared genetic predisposition between synaesthesia and autism, and more extreme synaesthetes may tend to hail from more neurodiverse families.
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Affiliation(s)
- Max Nugent
- School of Psychology University of Sussex, Brighton, UK
| | - Jamie Ward
- School of Psychology University of Sussex, Brighton, UK
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Yue Y, Hu YJ. A new approach to testing mediation of the microbiome at both the community and individual taxon levels. Bioinformatics 2022; 38:3173-3180. [PMID: 35512399 PMCID: PMC9191207 DOI: 10.1093/bioinformatics/btac310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/28/2022] [Accepted: 05/02/2022] [Indexed: 12/15/2022] Open
Abstract
MOTIVATION Understanding whether and which microbes played a mediating role between an exposure and a disease outcome are essential for researchers to develop clinical interventions to treat the disease by modulating the microbes. Existing methods for mediation analysis of the microbiome are often limited to a global test of community-level mediation or selection of mediating microbes without control of the false discovery rate (FDR). Further, while the null hypothesis of no mediation at each microbe is a composite null that consists of three types of null, most existing methods treat the microbes as if they were all under the same type of null, leading to excessive false positive results. RESULTS We propose a new approach based on inverse regression that regresses the microbiome data at each taxon on the exposure and the exposure-adjusted outcome. Then, the P-values for testing the coefficients are used to test mediation at both the community and individual taxon levels. This approach fits nicely into our Linear Decomposition Model (LDM) framework, so our new method LDM-med, implemented in the LDM framework, enjoys all the features of the LDM, e.g. allowing an arbitrary number of taxa to be tested simultaneously, supporting continuous, discrete, or multivariate exposures and outcomes (including survival outcomes), and so on. Using extensive simulations, we showed that LDM-med always preserved the FDR of testing individual taxa and had adequate sensitivity; LDM-med always controlled the type I error of the global test and had compelling power over existing methods. The flexibility of LDM-med for a variety of mediation analyses is illustrated by an application to a murine microbiome dataset, which identified several plausible mediating taxa. AVAILABILITY AND IMPLEMENTATION Our new method has been added to our R package LDM, which is available on GitHub at https://github.com/yijuanhu/LDM. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Ye Yue
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA
| | - Yi-Juan Hu
- To whom correspondence should be addressed.
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Gatzia DE, Arnaud S. Loving Objects: Can Autism Explain Objectophilia? ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:2117-2133. [PMID: 35536491 DOI: 10.1007/s10508-021-02281-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/18/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Objectophilia (also known as objectum-sexuality) involves romantic and sexual attraction to specific objects. Objectophiles often develop deep and enduring emotional, romantic, and sexual relations with specific inanimate (concrete or abstract) objects such as trains, bridges, cars, or words. The determinants of objectophilia are poorly understood. The aim of this paper is to examine the determining factors of objectophilia. We examine four hypotheses about the determinants of objectophilia (pertaining to fetishism, synesthesia, cross-modal mental imagery, and autism) and argue that the most likely determining factors of objectophilia are the social and non-social features of autism. Future studies on the determinants of objectophilia could enhance our understanding and potentially lessen the marginalization experienced by objectophiles.
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Affiliation(s)
- Dimitria Electra Gatzia
- Philosophy Department, The University of Akron, Akron, OH, USA
- Institute of Philosophy of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarah Arnaud
- Centre for Philosophical Psychology, University of Antwerp, Stadscampus - Gebouw D, D416, Grote Kauwenberg 18, Antwerp, 2000, Belgium.
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Simner J, Dance C. Dysikonesia or Aphantasia? Understanding the impact and history of names. A reply to. Cortex 2022; 153:220-223. [DOI: 10.1016/j.cortex.2022.04.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/26/2022]
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van Leeuwen TM, Wilsson L, Norrman HN, Dingemanse M, Bölte S, Neufeld J. Perceptual processing links autism and synesthesia: A co-twin control study. Cortex 2021; 145:236-249. [PMID: 34763130 DOI: 10.1016/j.cortex.2021.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 05/21/2021] [Accepted: 09/02/2021] [Indexed: 11/19/2022]
Abstract
Synesthesia occurs more commonly in individuals fulfilling criteria for an autism spectrum diagnosis than in the general population. It is associated with autistic traits and autism-related perceptual processing characteristics, including a more detail-focused attentional style and altered sensory sensitivity. In addition, these characteristics correlate with the degree of grapheme-color synesthesia (consistency of grapheme-color associations) in non-synesthetes. We investigated a predominantly non-synesthetic twin sample, including individuals fulfilling criteria for an autism spectrum diagnosis or other neurodevelopmental disorders (n = 65, 14-34 years, 60% female). We modelled linear relationships between the degree of grapheme-color synesthesia and autistic traits, sensory sensitivity, and visual perception, both within-twin pairs (22 pairs) where all factors shared by twins are implicitly controlled (including 50-100% genetics), and across the entire cohort. We found that the degree of grapheme-color synesthesia was associated with autistic traits within the domain of Attention to Details and with sensory hyper-, but not hypo-sensitivity. These associations were stronger within-twin pairs than across the sample. Further, twins with a higher degree of grapheme-color synesthesia were better than their co-twins at identifying fragmented images (Fragmented Pictures Test). This is the first twin study on the association between synesthesia and autism-related perceptual features and traits. The results suggest that investigating these associations within-twin pairs, implicitly adjusting for potential confounding factors shared by twins, is more sensitive than doing so in non-related individuals. Consistent with previous findings, the results suggest an association between the degree of grapheme-color synesthesia and autism-related perceptual features, while utilizing a different measure for sensory sensitivity. The novel finding of enhanced fragmented picture integration in twins with a higher degree of grapheme-color synesthesia challenges the view of a generally more detail-focused attentional style in synesthesia and might be related to enhanced memory or mental imagery in more synesthetic individuals.
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Affiliation(s)
- Tessa M van Leeuwen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Department of Communication and Cognition, Tilburg School of Humanities and Digital Sciences, Tilburg University, Tilburg, the Netherlands
| | - Lowe Wilsson
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
| | - Hjalmar Nobel Norrman
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
| | - Mark Dingemanse
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Centre for Language Studies, Radboud University, Nijmegen, the Netherlands
| | - Sven Bölte
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden; Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden; Curtin Autism Research Group, Curtin School of Allied Health, Curtin University, Perth, WA, Australia
| | - Janina Neufeld
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
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Navarro L, Martinón-Torres F, Salas A. Sensogenomics and the Biological Background Underlying Musical Stimuli: Perspectives for a New Era of Musical Research. Genes (Basel) 2021; 12:1454. [PMID: 34573436 PMCID: PMC8472585 DOI: 10.3390/genes12091454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/01/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023] Open
Abstract
What is the actual impact of music on the human being and the scope for scientific research in this realm? Compared to other areas, the study of the relationship between music and human biology has received limited attention. At the same time, evidence of music's value in clinical science, neuroscience, and social science keeps increasing. This review article synthesizes the existing knowledge of genetics related to music. While the success of genomics has been demonstrated in medical research, with thousands of genes that cause inherited diseases or a predisposition to multifactorial disorders identified, much less attention has been paid to other human traits. We argue for the development of a new discipline, sensogenomics, aimed at investigating the impact of the sensorial input on gene expression and taking advantage of new, discovery-based 'omic' approaches that allow for the exploration of the whole transcriptome of individuals under controlled experiments and circumstances.
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Affiliation(s)
- Laura Navarro
- Unidade de Xenética, Instituto de Ciencias Forenses (INCIFOR), Facultade de Medicina, Universidade de Santiago de Compostela, Galicia, 15706 Santiago de Compostela, Spain;
- GenPoB Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario de San-tiago (SERGAS), Galicia, 15706 Santiago de Compostela, Spain
- Genetics, Vaccines and Pediatric Infectious Diseases Research Group (GENVIP), Instituto de Investigación Sanitaria de Santiago (IDIS), Universidad de Santiago de Compostela (USC), Galicia, 15706 Santiago de Compostela, Spain;
| | - Federico Martinón-Torres
- Genetics, Vaccines and Pediatric Infectious Diseases Research Group (GENVIP), Instituto de Investigación Sanitaria de Santiago (IDIS), Universidad de Santiago de Compostela (USC), Galicia, 15706 Santiago de Compostela, Spain;
- Translational Pediatrics and Infectious Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela (SERGAS), Galicia, 15706 Santiago de Compostela, Spain
| | - Antonio Salas
- Unidade de Xenética, Instituto de Ciencias Forenses (INCIFOR), Facultade de Medicina, Universidade de Santiago de Compostela, Galicia, 15706 Santiago de Compostela, Spain;
- GenPoB Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario de San-tiago (SERGAS), Galicia, 15706 Santiago de Compostela, Spain
- Genetics, Vaccines and Pediatric Infectious Diseases Research Group (GENVIP), Instituto de Investigación Sanitaria de Santiago (IDIS), Universidad de Santiago de Compostela (USC), Galicia, 15706 Santiago de Compostela, Spain;
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van Leeuwen TM, Neufeld J, Hughes J, Ward J. Synaesthesia and autism: Different developmental outcomes from overlapping mechanisms? Cogn Neuropsychol 2020; 37:433-449. [PMID: 32845799 DOI: 10.1080/02643294.2020.1808455] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Synaesthesia, a mixing of the senses, is more common in individuals with autism. Here, we review the evidence for the association between synaesthesia and autism with regard to their genetic background, brain connectivity, perception, cognitive mechanisms and their contribution to exceptional talents. Currently, the overlap between synaesthesia and autism is established most convincingly at the level of alterations in sensory sensitivity and perception, with synaesthetes showing autism-like profiles of sensory sensitivity and a bias towards details in perception. Shared features may include a predominance of local over global connectivity in the brain. When autism and synaesthesia co-occur in the same individual, the chance of developing heightened cognitive and memory abilities is increased. We discuss how the same theoretical models could potentially explain both conditions. Given the evidence, we believe the phenotypical overlap between autism and synaesthesia has been established clearly enough to invite future research to confirm overlapping mechanisms.
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Affiliation(s)
- Tessa M van Leeuwen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Janina Neufeld
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
| | - James Hughes
- School of Psychology, University of Sussex, Brighton, UK
| | - Jamie Ward
- School of Psychology, University of Sussex, Brighton, UK
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Kirsch LP, Job X, Auvray M. Mixing up the Senses: Sensory Substitution Is Not a Form of Artificially Induced Synaesthesia. Multisens Res 2020; 34:297-322. [PMID: 33706280 DOI: 10.1163/22134808-bja10010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 05/26/2020] [Indexed: 11/19/2022]
Abstract
Sensory Substitution Devices (SSDs) are typically used to restore functionality of a sensory modality that has been lost, like vision for the blind, by recruiting another sensory modality such as touch or audition. Sensory substitution has given rise to many debates in psychology, neuroscience and philosophy regarding the nature of experience when using SSDs. Questions first arose as to whether the experience of sensory substitution is represented by the substituted information, the substituting information, or a multisensory combination of the two. More recently, parallels have been drawn between sensory substitution and synaesthesia, a rare condition in which individuals involuntarily experience a percept in one sensory or cognitive pathway when another one is stimulated. Here, we explore the efficacy of understanding sensory substitution as a form of 'artificial synaesthesia'. We identify several problems with previous suggestions for a link between these two phenomena. Furthermore, we find that sensory substitution does not fulfil the essential criteria that characterise synaesthesia. We conclude that sensory substitution and synaesthesia are independent of each other and thus, the 'artificial synaesthesia' view of sensory substitution should be rejected.
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Affiliation(s)
- Louise P Kirsch
- Institut des Systèmes Intelligents et de Robotique (ISIR), Sorbonne Université, Paris, France
| | - Xavier Job
- Institut des Systèmes Intelligents et de Robotique (ISIR), Sorbonne Université, Paris, France
| | - Malika Auvray
- Institut des Systèmes Intelligents et de Robotique (ISIR), Sorbonne Université, Paris, France
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Riedel A, Maier S, Wenzler K, Feige B, Tebartz van Elst L, Bölte S, Neufeld J. A case of co-occuring synesthesia, autism, prodigious talent and strong structural brain connectivity. BMC Psychiatry 2020; 20:342. [PMID: 32605557 PMCID: PMC7329514 DOI: 10.1186/s12888-020-02722-w] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 06/09/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Synesthesia is a sensory phenomenon where certain domain-specific stimuli trigger additional sensations of e.g. color or texture. The condition occurs in about 4% of the general population, but is overrepresented in individuals with Autism Spectrum Disorder (ASD), where it might also be associated with the presence of prodigious talents. CASE PRESENTATION Here we describe the case of a young transsexual man with Asperger Syndrome, synesthesia and a prodigious talent for foreign language acquisition. In our case, not only letters, numbers, spoken words, music, noises, weekdays and months lead to highly consistent, vivid color sensations but also his own and others' emotions, geometric shapes, any mathematical symbol, and letters from an unfamiliar alphabet (Hebrew). These color associations seem to aid categorization, differentiation and storage of information and might thereby contribute to the young man's language acquisition ability. We investigated the young man's structural brain connectivity in comparison to adults with or without ASD, applying global fiber tracking to diffusion-weighted Magnetic Resonance Imaging (MRI) data. The case presented with increased connectivity, especially between regions involved in visual and emotion processing, memory, and higher order associative binding regions. An electroencephalography experiment investigating synesthetic color and shape sensations while listening to music showed a negligible occipital alpha suppression, indicating that these internally generated synesthetic sensations derive from a different brain mechanism than when processing external visual information. CONCLUSIONS Taken together, this case study endorses the notion of a link between synesthesia, prodigious talent and autism, adding to the currently still sparse literature in this field. It provides new insights into the possible manifestations of synesthesia in individuals with ASD and its potential contribution to prodigious talents in people with an otherwise unexceptional cognitive profile. Additionally, this case impressively illustrates how synesthesia can be a key element not only of sensory perception but also social and emotional processing and contributes to existing evidence of increased brain connectivity in association with synesthesia.
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Affiliation(s)
- Andreas Riedel
- grid.7708.80000 0000 9428 7911Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Simon Maier
- grid.7708.80000 0000 9428 7911Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Kerstin Wenzler
- grid.7708.80000 0000 9428 7911Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Bernd Feige
- grid.7708.80000 0000 9428 7911Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Ludger Tebartz van Elst
- grid.7708.80000 0000 9428 7911Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Sven Bölte
- grid.4714.60000 0004 1937 0626Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research; Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden ,grid.1032.00000 0004 0375 4078Curtin Autism Research Group, Essential Partner Autism CRC, School of Occupational Therapy, Social Work and Speech Pathology, Curtin University, Perth, Western Australia ,grid.467087.a0000 0004 0442 1056Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
| | - Janina Neufeld
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research; Department of Women's and Children's Health, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden.
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Szyfter K, Witt MP. How far musicality and perfect pitch are derived from genetic factors? J Appl Genet 2020; 61:407-414. [PMID: 32533421 PMCID: PMC7413874 DOI: 10.1007/s13353-020-00563-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/31/2022]
Abstract
There is an agreement about joint genetic and environmental background of musical reception and performance. Musical abilities tend to cluster in families. The studies done on a random population, twins and families of gifted musicians provided a strong support for genetic contribution. Modern biomolecular techniques exploring linkage analysis, variation of gene copy number, scanning for whole-genome expression helped to identify genes, or chromosome regions associated with musical aptitude. Some studies were focused on rare ability to recognize tone without reference that is known as a perfect pitch where a far ethnic differentiation was established. On the other hand, gene deletion leading to dysfunction in amusical individuals also indicated appropriate loci “by negation.” The strongest support for an association of genes with musicality was provided for genes: AVPR1 (12q14.2), SLC6A4 (17q11.2), GALM (2p22), PCDH7 (4p15.1), GATA2 (3q21.3), and few others as well for 4q22, 4q23, and 8q13–21 chromosome bands.
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Affiliation(s)
- Krzysztof Szyfter
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszyńska 32, 60-479, Poznań, Poland
| | - Michał P Witt
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszyńska 32, 60-479, Poznań, Poland.
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Basirat A, Hupé JM. Synesthesia in children with difficulties in written language learning. Conscious Cogn 2020; 82:102951. [PMID: 32446188 DOI: 10.1016/j.concog.2020.102951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 11/17/2022]
Abstract
We tested whether the acquisition of grapheme-color synesthesia during childhood is related to difficulties in written language learning by measuring whether it is more frequent in 79 children receiving speech and language therapy for such difficulties than in the general population of children (1.3%). By using criteria as similar as possible to those used in the reference study (Simner et al., 2009), we did not identify any synesthete (Bayesian 95% credible interval [0, 4.5]% for a flat prior). The odds of the null model (no difference between 0/79 and 1.3%) over alternative models is 28 (Bayes Factor). A higher prevalence of grapheme-color synesthetes among children with learning difficulties is therefore very unlikely, questioning the hypothesis of a link between synesthesia and difficulties in language acquisition. We also describe the difficulty of diagnosing synesthesia in children and discuss the need for new approaches to do so.
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Affiliation(s)
- Anahita Basirat
- Univ. Lille, CNRS, UMR 9193 - SCALab - Sciences Cognitives et Sciences Affectives, F-59000 Lille, France.
| | - Jean-Michel Hupé
- Univ. Toulouse Paul Sabatier, CNRS, UMR 5549 - CerCo - Centre de Recherche Cerveau et Cognition, F-31000 Toulouse, France
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Maurer D, Ghloum JK, Gibson LC, Watson MR, Chen LM, Akins K, Enns JT, Hensch TK, Werker JF. Reduced perceptual narrowing in synesthesia. Proc Natl Acad Sci U S A 2020; 117:10089-10096. [PMID: 32321833 PMCID: PMC7211996 DOI: 10.1073/pnas.1914668117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synesthesia is a neurologic trait in which specific inducers, such as sounds, automatically elicit additional idiosyncratic percepts, such as color (thus "colored hearing"). One explanation for this trait-and the one tested here-is that synesthesia results from unusually weak pruning of cortical synaptic hyperconnectivity during early perceptual development. We tested the prediction from this hypothesis that synesthetes would be superior at making discriminations from nonnative categories that are normally weakened by experience-dependent pruning during a critical period early in development-namely, discrimination among nonnative phonemes (Hindi retroflex /d̪a/ and dental /ɖa/), among chimpanzee faces, and among inverted human faces. Like the superiority of 6-mo-old infants over older infants, the synesthetic groups were significantly better than control groups at making all the nonnative discriminations across five samples and three testing sites. The consistent superiority of the synesthetic groups in making discriminations that are normally eliminated during infancy suggests that residual cortical connectivity in synesthesia supports changes in perception that extend beyond the specific synesthetic percepts, consistent with the incomplete pruning hypothesis.
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Affiliation(s)
- Daphne Maurer
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1;
| | - Julian K Ghloum
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Laura C Gibson
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Marcus R Watson
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Lawrence M Chen
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Kathleen Akins
- Department of Philosophy, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - James T Enns
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Takao K Hensch
- Center for Brain Science, Department of Molecular Cellular Biology, Harvard University, Cambridge, MA 02138
- Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1M1
- International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, Bunkyo-ku, Tokyo, Japan 113-0033
| | - Janet F Werker
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Canadian Institute for Advanced Research, Toronto, ON, Canada M5G 1M1
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14
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Simner J, Hughes JEA, Sagiv N. Objectum sexuality: A sexual orientation linked with autism and synaesthesia. Sci Rep 2019; 9:19874. [PMID: 31882730 PMCID: PMC6934473 DOI: 10.1038/s41598-019-56449-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 12/06/2019] [Indexed: 01/06/2023] Open
Abstract
Objectum-sexuality (OS) is a sexual orientation which has received little attention in the academic literature. Individuals who identify as OS experience emotional, romantic and/or sexual feelings towards inanimate objects (e.g. a bridge, a statue). We tested 34 OS individuals and 88 controls, and provide the first empirical evidence that OS is linked to two separate neurodevelopmental traits - autism and synaesthesia. We show that OS individuals possess significantly higher rates of diagnosed autism and significantly stronger autistic traits compared to controls, as well as a significantly higher prevalence of synaesthesia, and significant synaesthetic traits inherent in the nature of their attractions. Our results suggest that OS may encapsulate autism and synaesthesia within its phenomenology. Our data speak to debates concerning the biological underpinnings of sexuality, to models of autism and synaesthesia, and to psychological and philosophical models of romantic love.
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Affiliation(s)
- Julia Simner
- School of Psychology, Pevensey Building, University of Sussex, Brighton, BN1 9QJ, UK.
| | - James E A Hughes
- School of Psychology, Pevensey Building, University of Sussex, Brighton, BN1 9QJ, UK
| | - Noam Sagiv
- Centre for Cognitive Neuroscience, College of Health and Life Sciences, Brunel University, London, Uxbridge, UB8 3PN, UK
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15
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Tilot AK, Vino A, Kucera KS, Carmichael DA, van den Heuvel L, den Hoed J, Sidoroff-Dorso AV, Campbell A, Porteous DJ, St Pourcain B, van Leeuwen TM, Ward J, Rouw R, Simner J, Fisher SE. Investigating genetic links between grapheme-colour synaesthesia and neuropsychiatric traits. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190026. [PMID: 31630655 PMCID: PMC6834005 DOI: 10.1098/rstb.2019.0026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2019] [Indexed: 12/22/2022] Open
Abstract
Synaesthesia is a neurological phenomenon affecting perception, where triggering stimuli (e.g. letters and numbers) elicit unusual secondary sensory experiences (e.g. colours). Family-based studies point to a role for genetic factors in the development of this trait. However, the contributions of common genomic variation to synaesthesia have not yet been investigated. Here, we present the SynGenes cohort, the largest genotyped collection of unrelated people with grapheme-colour synaesthesia (n = 723). Synaesthesia has been associated with a range of other neuropsychological traits, including enhanced memory and mental imagery, as well as greater sensory sensitivity. Motivated by the prior literature on putative trait overlaps, we investigated polygenic scores derived from published genome-wide scans of schizophrenia and autism spectrum disorder (ASD), comparing our SynGenes cohort to 2181 non-synaesthetic controls. We found a very slight association between schizophrenia polygenic scores and synaesthesia (Nagelkerke's R2 = 0.0047, empirical p = 0.0027) and no significant association for scores related to ASD (Nagelkerke's R2 = 0.00092, empirical p = 0.54) or body mass index (R2 = 0.00058, empirical p = 0.60), included as a negative control. As sample sizes for studying common genomic variation continue to increase, genetic investigations of the kind reported here may yield novel insights into the shared biology between synaesthesia and other traits, to complement findings from neuropsychology and brain imaging. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.
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Affiliation(s)
- Amanda K. Tilot
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
- Imaging Genetics Center, Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA 90033, USA
| | - Arianna Vino
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
| | - Katerina S. Kucera
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
| | - Duncan A. Carmichael
- School of Applied Sciences, Edinburgh Napier University, Sighthill Court, Edinburgh EH11 4BN, UK
| | - Loes van den Heuvel
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
| | - Joery den Hoed
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
| | | | - Archie Campbell
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
- Usher Institute for Population Health Sciences and Informatics, University of Edinburgh, Edinburgh EH16 4UX, UK
| | - David J. Porteous
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Beate St Pourcain
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
| | - Tessa M. van Leeuwen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 HE Nijmegen, The Netherlands
| | - Jamie Ward
- School of Psychology, University of Sussex, Brighton BN1 9RH, UK
| | - Romke Rouw
- Department of Psychology, University of Amsterdam, 1018 WT Amsterdam, The Netherlands
| | - Julia Simner
- School of Psychology, University of Sussex, Brighton BN1 9RH, UK
| | - Simon E. Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 HE Nijmegen, The Netherlands
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16
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Schwartzman DJ, Bor D, Rothen N, Seth AK. Neurophenomenology of induced and natural synaesthesia. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190030. [PMID: 31630656 PMCID: PMC6834010 DOI: 10.1098/rstb.2019.0030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2019] [Indexed: 12/15/2022] Open
Abstract
People with synaesthesia have additional perceptual experiences, which are automatically and consistently triggered by specific inducing stimuli. Synaesthesia therefore offers a unique window into the neurocognitive mechanisms underlying conscious perception. A long-standing question in synaesthesia research is whether it is possible to artificially induce non-synaesthetic individuals to have synaesthesia-like experiences. Although synaesthesia is widely considered a congenital condition, increasing evidence points to the potential of a variety of approaches to induce synaesthesia-like experiences, even in adulthood. Here, we summarize a range of methods for artificially inducing synaesthesia-like experiences, comparing the resulting experiences to the key hallmarks of natural synaesthesia which include consistency, automaticity and a lack of 'perceptual presence'. We conclude that a number of aspects of synaesthesia can be artificially induced in non-synaesthetes. These data suggest the involvement of developmental and/or learning components in the acquisition of synaesthesia, and they extend previous reports of perceptual plasticity leading to dramatic changes in perceptual phenomenology in adults. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.
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Affiliation(s)
- David J. Schwartzman
- Sackler Centre for Consciousness Science, University of Sussex, Brighton BN1 9QJ, UK
- Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK
| | - Daniel Bor
- Department of Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK
| | - Nicolas Rothen
- Sackler Centre for Consciousness Science, University of Sussex, Brighton BN1 9QJ, UK
- Faculty of Psychology, Swiss Distance University Institute, 3900 Brig, Switzerland
| | - Anil K. Seth
- Sackler Centre for Consciousness Science, University of Sussex, Brighton BN1 9QJ, UK
- Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK
- Azrieli Programme on Brain, Mind, and Consciousness, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
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17
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Smees R, Hughes J, Carmichael DA, Simner J. Learning in colour: children with grapheme-colour synaesthesia show cognitive benefits in vocabulary and self-evaluated reading. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180348. [PMID: 31630659 DOI: 10.1098/rstb.2018.0348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cognitive benefits associated with grapheme-colour synaesthesia in adults are well documented, but far less is known about whether such benefits might arise in synaesthetes as children. One previous study on a very small group of randomly sampled child synaesthetes found cognitive benefits in short-term memory and processing speed (the ability to quickly scan an array of images and discriminate between them), but was inconclusive for a test of receptive vocabulary. Using a stratified population sample (Growing Up in Scotland Project, Edinburgh, UK: Scottish Executive, 2007), we investigated the performance of a large cohort of child grapheme-colour synaesthetes using four literacy measures taken at age 10 years. These were three verbal comprehension measures (expressive vocabulary, receptive vocabulary and sentence comprehension) and one measure of academic self-concept in reading (plus one measure of academic self-concept in numeracy as a comparison). After controlling for demographic differences between groups, synaesthetes showed significantly enhanced performance for expressive and receptive vocabulary compared to their peers, but no benefits in sentence comprehension. Child synaesthetes also reported significantly higher academic self-concept for reading, but not for numeracy. Finally, we found that synaesthetes made significantly more progress than controls across the primary school years, although they began school with no a priori advantage. Our study provides powerful new evidence that children with grapheme-colour synaesthesia show vocabulary and literacy differences, which we contextualize within a theory of synaesthetic development. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.
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Affiliation(s)
- Rebecca Smees
- Department of Psychology, University of Sussex, Brighton BN1 9QH, UK
| | - James Hughes
- Department of Psychology, University of Sussex, Brighton BN1 9QH, UK
| | - Duncan A Carmichael
- School of Applied Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh EH11 4BN, UK
| | - Julia Simner
- Department of Psychology, University of Sussex, Brighton BN1 9QH, UK
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18
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Root NB, Dobkins K, Ramachandran VS, Rouw R. Echoes from the past: synaesthetic colour associations reflect childhood gender stereotypes. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180572. [PMID: 31630649 DOI: 10.1098/rstb.2018.0572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Grapheme-colour synaesthesia is a neurological phenomenon in which linguistic symbols evoke consistent colour sensations. Synaesthesia is believed to be influenced by both genetic and environmental factors, but how these factors interact to create specific associations in specific individuals is poorly understood. In this paper, we show that a grapheme-colour association in adult synaesthetes can be traced to a particular environmental effect at a particular moment in childhood. We propose a model in which specific grapheme-colour associations are 'locked in' during development in children predisposed to become synaesthetes, whereas grapheme-colour associations remain flexible in non-synaesthetes. We exploit Western gender-colour stereotypes to test our model: we found that young girls in general tend to associate their first initial with the colour pink. Consistent with our model, adult female synaesthetes are influenced by their childhood environment: they associate their first initial with pink. Adult female non-synaesthetes do not show this bias. Instead, in our study, non-synaesthetes tended to associate their first initial with their current favourite colour. The results thus support the 'locking in' model of synaesthesia, suggesting that synaesthetic associations can be used as a 'time capsule', revealing childhood influences on adult linguistic associations. Grapheme-colour synaesthesia may thus offer an extraordinary opportunity to study linguistic development. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.
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Affiliation(s)
- Nicholas B Root
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093-0109, USA
| | - Karen Dobkins
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093-0109, USA
| | - Vilayanur S Ramachandran
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093-0109, USA
| | - Romke Rouw
- Brain and Cognition, Psychology Department, University of Amsterdam, Nieuwe Achtergracht 129-B, 1018 WT Amsterdam, The Netherlands
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19
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Asano M, Takahashi SI, Tsushiro T, Yokosawa K. Synaesthetic colour associations for Japanese Kanji characters: from the perspective of grapheme learning. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180349. [PMID: 31630661 DOI: 10.1098/rstb.2018.0349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
One of the fundamental questions about grapheme-colour synaesthesia is how specific associations between the graphemes and colours are formed. We addressed this question by focusing on the determinants of synaesthetic colours for Japanese Kanji characters (logographic characters) using a psycholinguistic approach. Study 1 explored the influence meaning has on synaesthetic colours for Kanji characters representing abstract meanings by examining synaesthetic colours for antonym pairs (i.e. characters with meanings opposed to each other) in Japanese synaesthetes. Results showed that semantic relations influenced the grapheme-colour associations for characters representing abstract meanings in the early stages of learning abstract Kanji, while the influence was reduced in the grapheme-colour associations for those learned later. Study 2 examined the effect that learning new sounds or meanings of graphemes has on synaesthetic colours for those graphemes. Japanese synaesthetes were taught new sounds or new meanings for familiar Kanji characters. Results indicated that acquiring new information for graphemes slightly but significantly reduced the test-retest grapheme-colour association consistency, suggesting that synaesthetic colours can be modulated to reflect the synaesthete's latest knowledge about graphemes. Implications of these findings are discussed from the perspective of the relationship between synaesthesia and grapheme learning. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.
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Affiliation(s)
- Michiko Asano
- Department of Psychology, College of Contemporary Psychology, Rikkyo University, 1-2-26 Kitano, Niiza-shi, Saitama 352-8558, Japan
| | - So-Ichiro Takahashi
- Department of Psychology, Faculty of Letters, Graduate School of Humanities and Sociology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takuya Tsushiro
- Department of Psychology, Faculty of Letters, Graduate School of Humanities and Sociology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazuhiko Yokosawa
- Department of Psychology, Graduate School of Humanities and Sociology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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20
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Brang D, Ahn E. Double-blind study of visual imagery in grapheme-color synesthesia. Cortex 2019; 117:89-95. [PMID: 30952052 PMCID: PMC6956568 DOI: 10.1016/j.cortex.2019.02.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 11/16/2018] [Accepted: 02/23/2019] [Indexed: 11/25/2022]
Abstract
Synesthesia is an atypical perceptual phenomenon that has been associated with generalized differences in other cognitive and perceptual domains. Given similarities in the qualitative nature of synesthetic experiences to visual imagery perceptions, several studies have sought to examine whether synesthetes demonstrate increased visual imagery abilities. Using subjective imagery questionnaires, some studies have identified superior imaging abilities in synesthetes, while others have not. However, because most research on synesthesia uses un-blinded group membership prior to data collection, such methods for studying group differences may be prone to participant and experimenter biases (e.g., a motivated synesthete may rate themselves as having stronger visual imagery abilities due to their own bias and perceived experimenter expectations). To address this issue, we demonstrate the feasibility of double-blind designs in synesthesia research, applied here to examine differences in subjectively reported levels of imagery usage and intensity. Prior to identifying synesthetes' and non-synesthetes' group membership (in order to eliminate the potential for bias), subjects completed two common measures of visual imagery experiences. Using this approach, we replicated findings of greater visual imagery usage in synesthetes on the Spontaneous Use of Imagery Scale (SUIS) measure, but not of enhanced imagery abilities on the standardized Vividness of Visual Imagery Questionnaire (VVIQ) measure. The present study strengthens prior evidence that synesthesia is associated with heightened visual imagery and demonstrates the utility of double-blind designs in order to limit biases and promote further replicability of other findings in research on synesthesia.
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21
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Ovalle Fresa R, Rothen N. Development of synaesthetic consistency: Repeated autonomous engagement with graphemes and colours leads to consistent associations. Conscious Cogn 2019; 73:102764. [DOI: 10.1016/j.concog.2019.102764] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/07/2019] [Accepted: 06/02/2019] [Indexed: 11/28/2022]
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22
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Császár N, Kapócs G, Bókkon I. A possible key role of vision in the development of schizophrenia. Rev Neurosci 2019; 30:359-379. [PMID: 30244235 DOI: 10.1515/revneuro-2018-0022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022]
Abstract
Based on a brief overview of the various aspects of schizophrenia reported by numerous studies, here we hypothesize that schizophrenia may originate (and in part be performed) from visual areas. In other words, it seems that a normal visual system or at least an evanescent visual perception may be an essential prerequisite for the development of schizophrenia as well as of various types of hallucinations. Our study focuses on auditory and visual hallucinations, as they are the most prominent features of schizophrenic hallucinations (and also the most studied types of hallucinations). Here, we evaluate the possible key role of the visual system in the development of schizophrenia.
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Affiliation(s)
- Noemi Császár
- Gaspar Karoly University Psychological Institute, H-1091 Budapest, Hungary.,Psychoszomatic Outpatient Department, H-1037 Budapest, Hungary
| | - Gabor Kapócs
- Buda Family Centred Mental Health Centre, Department of Psychiatry and Psychiatric Rehabilitation, St. John Hospital, Budapest, Hungary
| | - István Bókkon
- Psychoszomatic Outpatient Department, H-1037 Budapest, Hungary.,Vision Research Institute, Neuroscience and Consciousness Research Department, 25 Rita Street, Lowell, MA 01854, USA
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23
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Landmann J, Richter F, Classen J, Richter A, Penninger JM, Bechmann I. Behavioral phenotyping of calcium channel (CACN) subunit α2δ3 knockout mice: Consequences of sensory cross-modal activation. Behav Brain Res 2019; 364:393-402. [DOI: 10.1016/j.bbr.2017.12.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/19/2017] [Accepted: 12/26/2017] [Indexed: 01/14/2023]
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24
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Nair A, Brang D. Inducing synesthesia in non-synesthetes: Short-term visual deprivation facilitates auditory-evoked visual percepts. Conscious Cogn 2019; 70:70-79. [PMID: 30852449 PMCID: PMC6436976 DOI: 10.1016/j.concog.2019.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/18/2019] [Accepted: 02/23/2019] [Indexed: 12/19/2022]
Abstract
Sounds can modulate activity in visual cortex, facilitating the detection of visual targets. However, these sound-driven modulations are not thought to evoke conscious visual percepts in the general population. In individuals with synesthesia, however, multisensory interactions do lead to qualitatively different experiences such as sounds evoking flashes of light. Why, if multisensory interactions are present in all individuals, do only synesthetes experience abnormal qualia? Competing models differ in the time required for synesthetic experiences to emerge. The cross-activation model suggests synesthesia arises over months or years from the development of abnormal neural connections. Here we demonstrate that after ∼5 min of visual deprivation, sounds can evoke synesthesia-like percepts (vivid colors and Klüver form-constants) in ∼50% of non-synesthetes. These results challenge aspects of the cross-activation model and suggest that synesthesia exists as a latent feature in all individuals, manifesting when the balance of activity across the senses has been altered.
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Affiliation(s)
- Anupama Nair
- Department of Psychology, University of Michigan, United States
| | - David Brang
- Department of Psychology, University of Michigan, United States.
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25
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Mealor AD, Simner J, Ward J. Does synaesthesia protect against age‐related memory loss? J Neuropsychol 2019; 14:197-212. [DOI: 10.1111/jnp.12182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 03/01/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Andy D. Mealor
- School of Psychology Sackler Centre for Consciousness Science University of Sussex Brighton UK
| | - Julia Simner
- School of Psychology Sackler Centre for Consciousness Science University of Sussex Brighton UK
| | - Jamie Ward
- School of Psychology Sackler Centre for Consciousness Science University of Sussex Brighton UK
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26
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Bouvet L, Amsellem F, Maruani A, Tonus-Vic Dupont A, Mathieu A, Bourgeron T, Delorme R, Mottron L. Synesthesia & autistic features in a large family: Evidence for spatial imagery as a common factor. Behav Brain Res 2019; 362:266-272. [PMID: 30639511 DOI: 10.1016/j.bbr.2019.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND Autism and synesthesia are neurodevelopmental conditions associated with variants of perceptual processing. They also share some genetic variants and include a large magnitude of intra-categorical variation: 60 types for synesthesia, as well as a spectrum for autism. In order to investigate the relationship between these two phenomena, we investigated the family of FC, an autistic individual who also possess savant abilities and synesthesia manifestations. METHOD Autistic symptoms were assessed for the entire sample of participants entering the study (39 individuals) using the SRS. Participants above threshold were evaluated with standardized diagnostic tools. Synesthesia was explored in the entire participating sample using a self-reported questionnaire. Consistency tests were used for participants who reported synesthetic manifestations. RESULTS In addition to FC, four individuals with ASD were detected. Fifteen participants self-reported synesthesia (15 sequence-space, 4 sound-shape, 4 day-color), among which nine sequence-space synesthetes satisfied the consistency criteria. Two participants possess both autism and synesthesia. CONCLUSION This family illustrates the co-segregation of autism and synesthesia. This co-segregation is in favour of a partially overlapping genetic predisposition for both conditions, but also authorizes a large variety of manifestations in both conditions. The high prevalence of sequence-space synesthesia in this family strengthens the previous assumption that this form of synesthesia may be linked to autism. We discuss the potential role of spatial imagery in the development of this form of synesthesia and savant abilities.
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Affiliation(s)
- Lucie Bouvet
- Laboratoire CERPPS (EA7411), Université Toulouse Jean Jaurés, Toulouse, France.
| | - Frédérique Amsellem
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; Child and Adolescent Psychiatry Department, Hôpital Robert-Debré, APHP, 75019, Paris, France; Fondation FondaMental, 94000, Créteil, France
| | - Anna Maruani
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; Child and Adolescent Psychiatry Department, Hôpital Robert-Debré, APHP, 75019, Paris, France
| | - Adelaïde Tonus-Vic Dupont
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; Child and Adolescent Psychiatry Department, Hôpital Robert-Debré, APHP, 75019, Paris, France
| | - Alexandre Mathieu
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; CNRS UMR 3571: Genes, Synapses and Cognition, Institut Pasteur, Paris, France
| | - Thomas Bourgeron
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; CNRS UMR 3571: Genes, Synapses and Cognition, Institut Pasteur, Paris, France; Fondation FondaMental, 94000, Créteil, France; Université Paris Diderot, Sorbonne Paris Cité, Human Genetics and Cognitive Functions, Paris, France
| | - Richard Delorme
- Human Genetics and Cognitive Functions Unit, Institut Pasteur, Paris, France; CNRS UMR 3571: Genes, Synapses and Cognition, Institut Pasteur, Paris, France; Child and Adolescent Psychiatry Department, Hôpital Robert-Debré, APHP, 75019, Paris, France; Fondation FondaMental, 94000, Créteil, France; Université Paris Diderot, Sorbonne Paris Cité, Human Genetics and Cognitive Functions, Paris, France
| | - Laurent Mottron
- Center of Excellence for Pervasive Developmental Disorders of the University of Montreal (CETEDUM), Rivières-des-Prairies Hospital, Montreal, Quebec, Canada; Research Center of CIUSSS of the North of Montreal and Department of Psychiatry, University of Montreal, Montreal, Quebec, Canada
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27
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Hoffman SN, Urosevich TG, Kirchner HL, Boscarino JJ, Dugan RJ, Withey CA, Adams RE, Figley CR, Boscarino JA. Grapheme-Color Synesthesia is Associated with PTSD Among Deployed Veterans: Confirmation of Previous Findings and Need for Additional Research. INTERNATIONAL JOURNAL OF EMERGENCY MENTAL HEALTH 2019; 21:https://www.omicsonline.org/open-access/graphemecolor-synesthesia-is-associated-with-ptsd-among-deployed-veterans-confirmation-of-previous-findings-and-need-for-additiona-1522-4821-108513.html. [PMID: 31285710 PMCID: PMC6613655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Post-traumatic stress disorder (PTSD) is related to alteration in neuropsychological functioning, including visual and other cognitive processes. Grapheme-color synesthesia is a phenomenon in which a letter or number elicits response of a concurrent image or color perception. Since we earlier reported an association between grapheme-color synesthesia and PTSD, our objective in the current study was to validate this association among a new study group and assess risk factors. For this, we surveyed 1,730 military veterans who have been outpatients in the Geisinger Clinic, a multi-hospital system in Pennsylvania, USA. All the study veterans served in a warzone deployment. The association between PTSD and Grapheme-color synesthesia was evaluated. The average age of veterans was 59.6 years among whom 95.1% were male. Current PTSD prevalence rate was observed to be 7.6% (95% C.I. = 6.5-9.0) and in 3.4% of veterans (95% C.I. = 2.7-4.4) grapheme-color synesthesia was found to be positive. Initial bivariate analyses suggested that synesthesia was associated with current PTSD [odds ratio (OR) = 3.3, p<0.001]. Multivariable stepwise logistic regression evaluating the age, sex, education, trauma exposure, current psychological stress, psychotropic medication use, combat exposure, history of concussion, and current depression, confirmed this association (OR = 2.33, p = 0.019). The present study corroborated that Grapheme-color synesthesia was linked to PTSD among a second cohort of deployed military veterans. Further research is recommended in order to validate this observation and to determine whether synesthesia is a risk factor for PTSD.
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Affiliation(s)
| | | | - H. Lester. Kirchner
- Biomedical and Translational Informatics, Geisinger Clinic, Danville, PA, USA
| | | | - Ryan J. Dugan
- Department of Epidemiology and Health Services Research, Geisinger Clinic, Danville, PA, USA
| | - Carrie A. Withey
- Department of Epidemiology and Health Services Research, Geisinger Clinic, Danville, PA, USA
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Bankieris KR, Qian T, Aslin RN. Synesthetes perseverate in implicit learning: Evidence from a non-stationary statistical learning task. Q J Exp Psychol (Hove) 2018; 72:1771-1779. [PMID: 30537900 DOI: 10.1177/1747021818816285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Synesthetes automatically and consistently experience additional sensory or cognitive perceptions in response to particular environmental stimuli. Recent evidence suggests that the propensity to develop synesthesia is genetic while the particular associations experienced by a given synesthete are influenced by learning. Despite the potential role of implicit learning in the formation of synesthetic associations, there has been minimal investigation of synesthetes' implicit learning abilities. In this study, we examine linguistic-colour synesthetes' ability to implicitly learn from and adjust to non-stationary statistics in a domain unrelated to their particular form of synesthesia. Engaging participants in a computer game Whack-the-mole, we utilise the online measure of reaction time to assess the time course of learning. Participants are exposed to "worlds" of probabilities that, unbeknownst to them, undergo unannounced changes, creating unpredictable statistical shifts devoid of accompanying cues. The same small set of probability worlds are repeated throughout the experiment to investigate participants' ability to retain and learn from this repetitive probabilistic information. The reaction time data provide evidence that synesthetes require more information than nonsynesthetes to benefit from the non-stationary probability distributions. These findings demonstrate that linguistic-colour synesthetes' implicit learning abilities-in a domain far from their synesthetic experiences-differ from those of nonsynesthetes.
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Affiliation(s)
- Kaitlyn R Bankieris
- 1 Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Ting Qian
- 2 Department of Psychology, Princeton University, Princeton, NJ, USA
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Fornazzari L, Leggieri M, Schweizer TA, Arizaga RL, Allegri RF, Fischer CE. Hyper memory, synaesthesia, savants Luria and Borges revisited. Dement Neuropsychol 2018; 12:101-104. [PMID: 29988344 PMCID: PMC6022980 DOI: 10.1590/1980-57642018dn12-020001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In this paper, we investigated two subjects with superior memory, or hyper memory: Solomon Shereshevsky, who was followed clinically for years by A. R. Luria, and Funes the Memorious, a fictional character created by J. L. Borges. The subjects possessed hyper memory, synaesthesia and symptoms of what we now call autistic spectrum disorder (ASD). We will discuss interactions of these characteristics and their possible role in hyper memory. Our study suggests that the hyper memory in our synaesthetes may have been due to their ASD-savant syndrome characteristics. However, this talent was markedly diminished by their severe deficit in categorization, abstraction and metaphorical functions. As investigated by previous studies, we suggest that there is altered connectivity between the medial temporal lobe and its connections to the prefrontal cingulate and amygdala, either due to lack of specific neurons or to a more general neuronal dysfunction.
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Affiliation(s)
- Luis Fornazzari
- MD, FRCPC. Department of Medicine, Behavioural Neurology Division, University of Toronto, Toronto, ON, Canada, M5S 1A8. St Michael's Hospital Memory Disorders Clinic, St. Michael's Hospital, Toronto, ON, Canada, M5S 1A8. Faculty of Medicine, Department of Psychiatry, University of Toronto, Canada, M5S 1A8
| | - Melissa Leggieri
- BSc. Keenan Research Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada M5B 1T8. Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada, M5S 1A8
| | - Tom A Schweizer
- PhD. Department of Surgery, Division of Neurosurgery, University of Toronto, Toronto, ON, Canada, M5S 1A8. Keenan Research Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada M5B 1T8
| | - Raul L Arizaga
- MD. Faculty of Medicine, University of Buenos Aires, Viamonte 430, 1053 Buenos Aires, Argentina
| | - Ricardo F Allegri
- MD. Centro de Memoria y Envejecimiento. Ins Investigaciones Neurol "Raul Carrea" (FLENI) Buenos Aires, Argentina. Neurosciencias. Universidad de la Costa (CUC). Colombia
| | - Corinne E Fischer
- MD, FRCPC. St Michael's Hospital Memory Disorders Clinic, St. Michael's Hospital, Toronto, ON, Canada, M5S 1A8. Faculty of Medicine, Department of Psychiatry, University of Toronto, Canada, M5S 1A8. Keenan Research Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, 209 Victoria Street, Toronto, ON, Canada M5B 1T8
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Tilot AK, Kucera KS, Vino A, Asher JE, Baron-Cohen S, Fisher SE. Rare variants in axonogenesis genes connect three families with sound-color synesthesia. Proc Natl Acad Sci U S A 2018; 115:3168-3173. [PMID: 29507195 PMCID: PMC5866556 DOI: 10.1073/pnas.1715492115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Synesthesia is a rare nonpathological phenomenon where stimulation of one sense automatically provokes a secondary perception in another. Hypothesized to result from differences in cortical wiring during development, synesthetes show atypical structural and functional neural connectivity, but the underlying molecular mechanisms are unknown. The trait also appears to be more common among people with autism spectrum disorder and savant abilities. Previous linkage studies searching for shared loci of large effect size across multiple families have had limited success. To address the critical lack of candidate genes, we applied whole-exome sequencing to three families with sound-color (auditory-visual) synesthesia affecting multiple relatives across three or more generations. We identified rare genetic variants that fully cosegregate with synesthesia in each family, uncovering 37 genes of interest. Consistent with reports indicating genetic heterogeneity, no variants were shared across families. Gene ontology analyses highlighted six genes-COL4A1, ITGA2, MYO10, ROBO3, SLC9A6, and SLIT2-associated with axonogenesis and expressed during early childhood when synesthetic associations are formed. These results are consistent with neuroimaging-based hypotheses about the role of hyperconnectivity in the etiology of synesthesia and offer a potential entry point into the neurobiology that organizes our sensory experiences.
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Affiliation(s)
- Amanda K Tilot
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6500 AH Nijmegen, The Netherlands
| | - Katerina S Kucera
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6500 AH Nijmegen, The Netherlands
| | - Arianna Vino
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6500 AH Nijmegen, The Netherlands
| | - Julian E Asher
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge CB2 8AH, United Kingdom
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge CB2 8AH, United Kingdom
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6500 AH Nijmegen, The Netherlands;
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500 HE Nijmegen, The Netherlands
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Rothen N, Schwartzman DJ, Bor D, Seth AK. Coordinated neural, behavioral, and phenomenological changes in perceptual plasticity through overtraining of synesthetic associations. Neuropsychologia 2018; 111:151-162. [DOI: 10.1016/j.neuropsychologia.2018.01.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/19/2017] [Accepted: 01/19/2018] [Indexed: 10/18/2022]
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The structure of inter-individual differences in visual ability: Evidence from the general population and synaesthesia. Vision Res 2017; 141:293-302. [DOI: 10.1016/j.visres.2016.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 03/18/2016] [Accepted: 06/06/2016] [Indexed: 11/20/2022]
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Rothen N, Bartl G, Franklin A, Ward J. Electrophysiological correlates and psychoacoustic characteristics of hearing-motion synaesthesia. Neuropsychologia 2017; 106:280-288. [PMID: 28982544 DOI: 10.1016/j.neuropsychologia.2017.08.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/08/2017] [Accepted: 08/30/2017] [Indexed: 12/24/2022]
Abstract
People with hearing-motion synaesthesia experience sounds from moving or changing (e.g. flickering) visual stimuli. This phenomenon may be one of the most common forms of synaesthesia but it has rarely been studied and there are no studies of its neural basis. We screened for this in a sample of 200+ individuals, and estimated a prevalence of 4.2%. We also document its characteristics: it tends to be induced by physically moving stimuli (more so than static stimuli which imply motion or trigger illusory motion); and the psychoacoustic features are simple (e.g. "whooshing") with some systematic correspondences to vision (e.g. faster movement is higher pitch). We demonstrate using event-related potentials that it emerges from early perceptual processing of vision. The synaesthetes have a higher amplitude motion-evoked N2 (165-185ms), with some evidence of group differences as early as 55-75ms. We discuss similarities between hearing-motion synaesthesia and previous observations that visual motion triggers auditory activity in the congenitally deaf. It is possible that both conditions reflect the maintenance of multisensory pathways found in early development that most people lose but can be retained in certain people in response to sensory deprivation (in the deaf) or, in people with normal hearing, as a result of other differences (e.g. genes predisposing to synaesthesia).
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Affiliation(s)
- Nicolas Rothen
- University of Bern, Switzerland; Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
| | - Gergely Bartl
- School of Psychology, University of Sussex, Brighton, UK; Department of Psychology, University of Roehampton, London, UK
| | - Anna Franklin
- School of Psychology, University of Sussex, Brighton, UK
| | - Jamie Ward
- School of Psychology, University of Sussex, Brighton, UK; Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK.
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Landmann J, Richter F, Oros-Peusquens AM, Shah NJ, Classen J, Neely GG, Richter A, Penninger JM, Bechmann I. Neuroanatomy of pain-deficiency and cross-modal activation in calcium channel subunit (CACN) α2δ3 knockout mice. Brain Struct Funct 2017; 223:111-130. [PMID: 28733833 DOI: 10.1007/s00429-017-1473-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022]
Abstract
The phenotype of calcium channel subunit (CACN) α2δ3 knockout (KO) mice includes sensory cross-activation and deficient pain perception. Sensory cross-activation defines the activation of a sensory cortical region by input from another modality due to reorganization in the brain such as after sensory loss. To obtain mechanistic insight into both phenomena, we employed a comprehensive battery of neuroanatomical techniques. While CACNα2δ3 was ubiquitously expressed in wild-type mice, it was absent in α2δ3 KO animals. Immunostaining of α1A, α1B, and α1E revealed upregulation of N-type and R-type, but not P/Q-type Cav2 channels in cortical neurons of CACNα2δ3 KO mice. Compared to wild-type mice, axonal processes in somatosensory cortex were enhanced, and dendritic processes reduced, in CACNα2δ3 KO mice. Immunohistochemical and MRI analyses, investigating morphology, thalamocortical and intra-/intercortical trajectories, revealed a disparity between projection and commissural fibers with reduction of the number of spatial specificity of thalamocortical projections. L1cam staining revealed wide-ranging projections of thalamocortical fibers reaching both somatosensory/motor and visual cortical areas. Activation (c-fos+) of excitatory and inhibitory neurons suggested that deficient pain perception in α2δ3 KO mice is unlikely to result from cortical disinhibition. Collectively, our data demonstrate that knock out of CACN α2δ3 results in some structural abnormalities whose functional implications converge to dedifferentiation of sensory activation.
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Affiliation(s)
- Julia Landmann
- Institute of Anatomy, University of Leipzig, Oststrasse 25, 04317, Leipzig, Germany.
| | - Franziska Richter
- Department of Veterinary Medicine, Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103, Leipzig, Germany
| | - Ana-Maria Oros-Peusquens
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich, Forschungszentrum Jülich, 52425, Jülich, Germany.,Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - G Gregory Neely
- Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, 2006, Camperdown, NSW, Australia
| | - Angelika Richter
- Department of Veterinary Medicine, Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103, Leipzig, Germany
| | - Josef M Penninger
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Ingo Bechmann
- Institute of Anatomy, University of Leipzig, Oststrasse 25, 04317, Leipzig, Germany
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Colizoli O, Murre JMJ, Scholte HS, Rouw R. Creating Colored Letters: Familial Markers of Grapheme–Color Synesthesia in Parietal Lobe Activation and Structure. J Cogn Neurosci 2017; 29:1239-1252. [DOI: 10.1162/jocn_a_01105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
Perception is inherently subjective, and individual differences in phenomenology are well illustrated by the phenomenon of synesthesia (highly specific, consistent, and automatic cross-modal experiences, in which the external stimulus corresponding to the additional sensation is absent). It is unknown why some people develop synesthesia and others do not. In the current study, we tested whether neural markers related to having synesthesia in the family were evident in brain function and structure. Relatives of synesthetes (who did not have any type of synesthesia themselves) and matched controls read specially prepared books with colored letters for several weeks and were scanned before and after reading using magnetic resonance imaging. Effects of acquired letter–color associations were evident in brain activation. Training-related activation (while viewing black letters) in the right angular gyrus of the parietal lobe was directly related to the strength of the learned letter–color associations (behavioral Stroop effect). Within this obtained angular gyrus ROI, the familial trait of synesthesia related to brain activation differences while participants viewed both black and colored letters. Finally, we compared brain structure using voxel-based morphometry and diffusion tensor imaging to test for group differences and training effects. One cluster in the left superior parietal lobe had significantly more coherent white matter in the relatives compared with controls. No evidence for experience-dependent plasticity was obtained. For the first time, we present evidence suggesting that the (nonsynesthete) relatives of grapheme–color synesthetes show atypical grapheme processing as well as increased brain connectivity.
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Abstract
Although cross-modal neural connections and genetic underpinnings are prominent in most current theories regarding the development of synesthesia, the potential role of associative learning in the formation of synesthetic associations has recently been revitalized. In this study, we investigated implicit associative learning in synesthetes and nonsynesthetes by recording reaction times to a target whose color was probabilistically correlated with its shape. A continuous measure of target detection at multiple time points during learning revealed that synesthetes and nonsynesthetes learn associations differently. Specifically, our results demonstrated a "fast-facilitation" learning effect for nonsynesthetes and a "fast-interference, slow-facilitation" learning effect for synesthetes. Additionally, synesthetes exhibited superior long-term memory for the learned associations in a surprise delayed retest. After this retest, participants implicitly learned new (shuffled) shape-color associations. We found that synesthetes experienced greater interference while learning these new shape-color associations. These results detail ways in which implicit associative learning and memory differ between synesthetes and nonsynesthetes.
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Affiliation(s)
- Kaitlyn R Bankieris
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA.
| | - Richard N Aslin
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
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Abstract
Synesthetes, who see printed black letters and numbers as being colored, are thought to have enhanced cross-activation between brain modules for color and form. Since the McCollough effect also results from oriented contours (i.e., form) evoking specific colors, we conjectured that synesthetes may experience an enhanced McCollough effect, and find that this is indeed true.
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Affiliation(s)
- V S Ramachandran
- Center for Brain and Cognition, University of California at San Diego, La Jolla, CA, USA
| | - Zeve Marcus
- Center for Brain and Cognition, University of California at San Diego, La Jolla, CA, USA
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38
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Ward J, Hoadley C, Hughes JEA, Smith P, Allison C, Baron-Cohen S, Simner J. Atypical sensory sensitivity as a shared feature between synaesthesia and autism. Sci Rep 2017; 7:41155. [PMID: 28266503 PMCID: PMC5339734 DOI: 10.1038/srep41155] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/15/2016] [Indexed: 12/23/2022] Open
Abstract
Several studies have suggested that there is a link between synaesthesia and autism but the nature of that link remains poorly characterised. The present study considers whether atypical sensory sensitivity may be a common link between the conditions. Sensory hypersensitivity (aversion to certain sounds, touch, etc., or increased ability to make sensory discriminations) and/or hyposensitivity (desire to stimulate the senses , or a reduced response to sensory stimuli are a recently introduced diagnostic feature of autism spectrum conditions (ASC). Synaesthesia is defined by unusual sensory experiences and has also been linked to a typical cortical hyper-excitability. The Glasgow Sensory Questionnaire (GSQ) was administered to synaesthetes and people with ASC. Both groups reported increased sensory sensitivity relative to controls with a large effect size. Both groups also reported a similar pattern of both increased hyper- and hypo-sensitivities across multiple senses. The AQ (Autism-Spectrum Quotient) scores were elevated in the synaesthetes, and one subscale of this measure (attention to detail) placed synaesthetes within the autistic range. A standard laboratory test of visual stress (the Pattern Glare Test), administered online, corroborated the findings of increased sensitivity to aversive visual stimuli in synaesthetes. We conclude that atypical sensory sensitivity is an important shared feature between autism and synaesthesia.
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Affiliation(s)
- Jamie Ward
- School of Psychology and Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
| | - Claire Hoadley
- School of Psychology and Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
| | - James E. A. Hughes
- School of Psychology and Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
| | - Paula Smith
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK
| | - Carrie Allison
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK
| | - Julia Simner
- School of Psychology and Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
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Just DKC. Was Kandinsky a Synaesthete? Examining His Writings and Other Evidence. Multisens Res 2017; 30:447-460. [PMID: 31287076 DOI: 10.1163/22134808-00002547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 01/27/2017] [Indexed: 11/19/2022]
Abstract
Wassily Kandinsky is widely regarded as one of the most prominent examples of a synaesthetic artist. However, in the scientific literature there is disagreement on the genuineness of his synaesthesia. This paper investigates whether Kandinsky had inborn synaesthesia, while acknowledging that there are also types of induced synaesthesia which he may have cultivated. As these two types of synaesthesia are seen to work additively in some synaesthetes and not to be mutually exclusive, this is not seen as an argument against the view that he was a true inborn synaesthete. Whether Kandinsky was a synaesthete is examined through a detailed study of his primary writings (e.g., On the Spiritual in Art, Point and Line to Plane, and Reminiscences), in light of the modern diagnostic criteria. The experiences described in those writings indicate that his synaesthetic perceptions were genuine and inborn and not just a theoretical endeavour. Given the genetic dimension of synaesthesia, this view is further supported by the fact that Kandinsky's uncle Victor Kandinsky also described having synaesthetic experiences.
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Affiliation(s)
- Dyedra K C Just
- Department of Experimental Psychology, University of Oxford, Tinbergen Building, 9 South Parks Road, Oxford OX1 3UD, UK
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Hughes J, Simner J, Baron-Cohen S, Treffert D, Ward J. Is Synaesthesia More Prevalent in Autism Spectrum Conditions? Only Where There Is Prodigious Talent. Multisens Res 2017; 30:391-408. [DOI: 10.1163/22134808-00002558] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 02/19/2017] [Indexed: 12/28/2022]
Abstract
Savant syndrome is a condition where prodigious talent co-occurs with developmental difficulties such as autism spectrum conditions (ASC). To better understand savant skills, we previously proposed a link with synaesthesia: that savant syndrome may arise in ASC individuals who also happen to have synaesthesia. A second, unrelated claim is that people with autism may have higher rates of synaesthesia. Here we ask whether synaesthesia is indeed found more often in autism per se, or only in cases where autism co-occurs with savant skills. People with autism in previous studies when tested for synaesthesia were not differentiated into those with and without savant abilities. Here we tested three groups: people with autism who also have savant skills (), people with autism without savant skills (), and controls without autism (). We used a validated test to diagnose grapheme–colour synaesthesia. Results show a significantly higher prevalence of synaesthesia in people with ASC, but only those who also have savant skills. This suggests that synaesthesia in autism is linked to those with savant abilities rather than autism per se. We discuss the role of synaesthesia in the development of prodigious talent.
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Affiliation(s)
- James E. A. Hughes
- School of Psychology, Pevensey Building, University of Sussex, BN1 9QJ, UK
| | - Julia Simner
- School of Psychology, Pevensey Building, University of Sussex, BN1 9QJ, UK
- Department of Psychology, University of Edinburgh, 7 George Square, EH8 9JZ, UK
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge CB2 8AH, UK
| | - Darold A. Treffert
- Agnesian HealthCare, 430 East Division Street, Fond du Lac, WI 54935, USA
| | - Jamie Ward
- School of Psychology, Pevensey Building, University of Sussex, BN1 9QJ, UK
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Watson MR, Chromý J, Crawford L, Eagleman DM, Enns JT, Akins KA. The prevalence of synaesthesia depends on early language learning. Conscious Cogn 2016; 48:212-231. [PMID: 28013176 DOI: 10.1016/j.concog.2016.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 09/10/2016] [Accepted: 12/14/2016] [Indexed: 10/20/2022]
Abstract
According to one theory, synaesthesia develops, or is preserved, because it helps children learn. If so, it should be more common among adults who faced greater childhood learning challenges. In the largest survey of synaesthesia to date, the incidence of synaesthesia was compared among native speakers of languages with transparent (easier) and opaque (more difficult) orthographies. Contrary to our prediction, native speakers of Czech (transparent) were more likely to be synaesthetes than native speakers of English (opaque). However, exploratory analyses suggested that this was because more Czechs learned non-native second languages, which was strongly associated with synaesthesia, consistent with the learning hypothesis. Furthermore, the incidence of synaesthesia among speakers of opaque languages was double that among speakers of transparent languages other than Czech, also consistent with the learning hypothesis. These findings contribute to an emerging understanding of synaesthetic development as a complex and lengthy process with multiple causal influences.
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Affiliation(s)
- Marcus R Watson
- Department of Biology, York University, Toronto, Ontario, Canada.
| | - Jan Chromý
- Institute of the Czech Language and Theory of Communication, Charles University, Prague, Czech Republic
| | - Lyle Crawford
- Department of Philosophy, Simon Fraser University, Burnaby, BC, Canada
| | - David M Eagleman
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - James T Enns
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Kathleen A Akins
- Department of Philosophy, Simon Fraser University, Burnaby, BC, Canada
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Oikkonen J, Onkamo P, Järvelä I, Kanduri C. Convergent evidence for the molecular basis of musical traits. Sci Rep 2016; 6:39707. [PMID: 28004803 PMCID: PMC5177873 DOI: 10.1038/srep39707] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/25/2016] [Indexed: 12/30/2022] Open
Abstract
To obtain aggregate evidence for the molecular basis of musical abilities and the effects of music, we integrated gene-level data from 105 published studies across multiple species including humans, songbirds and several other animals and used a convergent evidence method to prioritize the top candidate genes. Several of the identified top candidate genes like EGR1, FOS, ARC, BDNF and DUSP1 are known to be activity-dependent immediate early genes that respond to sensory and motor stimuli in the brain. Several other top candidate genes like MAPK10, SNCA, ARHGAP24, TET2, UBE2D3, FAM13A and NUDT9 are located on chromosome 4q21-q24, on the candidate genomic region for music abilities in humans. Functional annotation analyses showed the enrichment of genes involved in functions like cognition, learning, memory, neuronal excitation and apoptosis, long-term potentiation and CDK5 signaling pathway. Interestingly, all these biological functions are known to be essential processes underlying learning and memory that are also fundamental for musical abilities including recognition and production of sound. In summary, our study prioritized top candidate genes related to musical traits.
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Affiliation(s)
- Jaana Oikkonen
- Department of Medical Genetics, University of Helsinki, P.O. Box 720, 00014 University of Helsinki, Finland.,Department of Biosciences, University of Helsinki, P.O. Box 56, 00014 University of Helsinki, Finland
| | - Päivi Onkamo
- Department of Biosciences, University of Helsinki, P.O. Box 56, 00014 University of Helsinki, Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki, P.O. Box 720, 00014 University of Helsinki, Finland
| | - Chakravarthi Kanduri
- Department of Medical Genetics, University of Helsinki, P.O. Box 720, 00014 University of Helsinki, Finland
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Janik McErlean AB, Susilo T, Rezlescu C, Bray A, Banissy MJ. Social perception in synaesthesia for colour. Cogn Neuropsychol 2016; 33:378-387. [PMID: 27937073 DOI: 10.1080/02643294.2016.1261820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Synaesthesia is a rare phenomenon in which stimulation in one modality (e.g., audition) evokes a secondary percept not associated with the first (e.g., colour). Prior work has suggested links between synaesthesia and other neurodevelopmental conditions that are linked to altered social perception abilities. With this in mind, here we sought to examine social perception abilities in grapheme-colour synaesthesia (where achromatic graphemes evoke colour experiences) by examining facial identity and facial emotion perception in synaesthetes and controls. Our results indicate that individuals who experience grapheme-colour synaesthesia outperformed controls on tasks involving fine visual discrimination of facial identity and emotion, but not on tasks involving holistic face processing. These findings are discussed in the context of broader perceptual and cognitive traits previously associated with synaesthesia for colour, with the suggestion that performance benefits shown by grapheme-colour synaesthetes may be related to domain-general visual discrimination biases observed in this group.
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Affiliation(s)
- Agnieszka B Janik McErlean
- a Department of Psychology , Goldsmiths University of London , London , UK.,b Department of Psychology , James Cook University , Singapore
| | - Tirta Susilo
- c School of Psychology , Victoria University of Wellington , Wellington , New Zealand
| | - Constantin Rezlescu
- d Department of Psychology , Harvard University , Cambridge , MA , USA.,e Institute of Cognitive Neuroscience , University College London , London , UK
| | - Amy Bray
- f Department of Psychological and Brain Sciences , Dartmouth College , Hanover , NH , USA
| | - Michael J Banissy
- a Department of Psychology , Goldsmiths University of London , London , UK
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Simner J, Rehme M, Carmichael D, Bastin M, Sprooten E, McIntosh A, Lawrie S, Zedler M. Social responsiveness to inanimate entities: Altered white matter in a ‘social synaesthesia’. Neuropsychologia 2016; 91:282-289. [DOI: 10.1016/j.neuropsychologia.2016.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/10/2016] [Accepted: 08/18/2016] [Indexed: 12/23/2022]
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Bankieris KR, Aslin RN. Explicit Associative Learning and Memory in Synesthetes and Nonsynesthetes. Iperception 2016; 7:2041669516658488. [PMID: 27698986 PMCID: PMC5030759 DOI: 10.1177/2041669516658488] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Most current theories regarding the development of synesthesia focus on cross-modal neural connections and genetic underpinnings, but recent evidence has revitalized the potential role of associative learning. In the present study, we compared synesthetes’ and controls’ ability to explicitly learn shape-color pairings. Using a continuous measure of accuracy and multiple testing blocks, we found that synesthetes learned these pairings faster than controls. In a delayed retest, synesthetes outperformed controls, demonstrating enhanced long-term memory for shape–color associations. Following this retest, participants learned shuffled associations, and we found little evidence for group differences in subsequent learning ability. Overall, our findings support the hypothesis that synesthetes have exceptional associative learning abilities and further specify that this advantage pertains to the initial learning rate and long-term retention of associations.
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Baron-Cohen S, Robson E, Lai MC, Allison C. Mirror-Touch Synaesthesia Is Not Associated with Heightened Empathy, and Can Occur with Autism. PLoS One 2016; 11:e0160543. [PMID: 27490947 PMCID: PMC4973977 DOI: 10.1371/journal.pone.0160543] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 07/20/2016] [Indexed: 02/03/2023] Open
Abstract
Research has linked Mirror-Touch (MT) synaesthesia with enhanced empathy. We test the largest sample of MT synaesthetes to date to examine two claims that have been previously made: that MT synaesthetes (1) have superior empathy; and (2) only ever experience their MT synaesthesia in response to viewing a person being touched. Given that autism has been suggested to involve deficits in cognitive empathy, we also test two predictions: that MT synaesthetes should (3) be less likely than general population individuals without MT synaesthesia to have an autism spectrum condition (ASC), if MT is characterized by superior empathy; and (4) have fewer autistic traits. We selected three groups: a pure MT synaesthesia group (N = 46), a pure grapheme-colour (GC) synaesthesia group (N = 36), and a typical control group without synaesthesia (N = 46). Participants took three measures of empathy and one measure of autistic traits. MT synaesthetes did not show enhanced empathy. In addition, 30% of all MT synaesthetes recruited into this study (N = 135) reported also having ASC, and MT synaesthetes showed higher autistic trait scores than controls. Finally, some MT experiences were reported in response to viewing objects being touched. Our findings dispute the views that MT synaesthesia is linked with enhanced empathy, is less likely to occur with ASC or elevated autistic traits, and is specific to seeing a person being touched.
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Affiliation(s)
- Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
- Cambridge Lifespan Asperger Syndrome Service (CLASS) Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
- * E-mail:
| | - Emma Robson
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
- Child and Youth Mental Health Collaborative at the Centre for Addiction and Mental Health and The Hospital for Sick Children, Department of Psychiatry, University of Toronto, Toronto, Canada
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - Carrie Allison
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
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The Emergence of Synaesthesia in a Neuronal Network Model via Changes in Perceptual Sensitivity and Plasticity. PLoS Comput Biol 2016; 12:e1004959. [PMID: 27392215 PMCID: PMC4938560 DOI: 10.1371/journal.pcbi.1004959] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 05/04/2016] [Indexed: 11/19/2022] Open
Abstract
Synaesthesia is an unusual perceptual experience in which an inducer stimulus triggers a percept in a different domain in addition to its own. To explore the conditions under which synaesthesia evolves, we studied a neuronal network model that represents two recurrently connected neural systems. The interactions in the network evolve according to learning rules that optimize sensory sensitivity. We demonstrate several scenarios, such as sensory deprivation or heightened plasticity, under which synaesthesia can evolve even though the inputs to the two systems are statistically independent and the initial cross-talk interactions are zero. Sensory deprivation is the known causal mechanism for acquired synaesthesia and increased plasticity is implicated in developmental synaesthesia. The model unifies different causes of synaesthesia within a single theoretical framework and repositions synaesthesia not as some quirk of aberrant connectivity, but rather as a functional brain state that can emerge as a consequence of optimising sensory information processing. Synaesthesia is a remarkable form of altered perception, where one attribute of a stimulus (e.g. sound) leads to the conscious experience of an additional attribute (often colour). Despite being known about for 200 years, there is no commonly agreed upon model for how and why synaesthesia emerges. This study presents a new model of synaesthesia based on computational principles that accounts for the emergence of different types of synaesthesia (acquired and developmental) as well as many of its key characteristics. The model describes how two independent neuronal systems can evolve to interact with one another even though their inputs are statistically uncorrelated. Specifically, synaesthesia arises as a result of instability in the learning process that shapes the network, which can be caused by heightened plasticity or due to sensory deprivation of one of the systems. The model unifies different aspects of synaesthesia and generates novel insights and predictions.
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Terhune DB, Luke DP, Kaelen M, Bolstridge M, Feilding A, Nutt D, Carhart-Harris R, Ward J. A placebo-controlled investigation of synaesthesia-like experiences under LSD. Neuropsychologia 2016; 88:28-34. [DOI: 10.1016/j.neuropsychologia.2016.04.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 03/18/2016] [Accepted: 04/04/2016] [Indexed: 10/22/2022]
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Oikkonen J, Kuusi T, Peltonen P, Raijas P, Ukkola-Vuoti L, Karma K, Onkamo P, Järvelä I. Creative Activities in Music--A Genome-Wide Linkage Analysis. PLoS One 2016; 11:e0148679. [PMID: 26909693 PMCID: PMC4766096 DOI: 10.1371/journal.pone.0148679] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/20/2016] [Indexed: 11/30/2022] Open
Abstract
Creative activities in music represent a complex cognitive function of the human brain, whose biological basis is largely unknown. In order to elucidate the biological background of creative activities in music we performed genome-wide linkage and linkage disequilibrium (LD) scans in musically experienced individuals characterised for self-reported composing, arranging and non-music related creativity. The participants consisted of 474 individuals from 79 families, and 103 sporadic individuals. We found promising evidence for linkage at 16p12.1-q12.1 for arranging (LOD 2.75, 120 cases), 4q22.1 for composing (LOD 2.15, 103 cases) and Xp11.23 for non-music related creativity (LOD 2.50, 259 cases). Surprisingly, statistically significant evidence for linkage was found for the opposite phenotype of creative activity in music (neither composing nor arranging; NCNA) at 18q21 (LOD 3.09, 149 cases), which contains cadherin genes like CDH7 and CDH19. The locus at 4q22.1 overlaps the previously identified region of musical aptitude, music perception and performance giving further support for this region as a candidate region for broad range of music-related traits. The other regions at 18q21 and 16p12.1-q12.1 are also adjacent to the previously identified loci with musical aptitude. Pathway analysis of the genes suggestively associated with composing suggested an overrepresentation of the cerebellar long-term depression pathway (LTD), which is a cellular model for synaptic plasticity. The LTD also includes cadherins and AMPA receptors, whose component GSG1L was linked to arranging. These results suggest that molecular pathways linked to memory and learning via LTD affect music-related creative behaviour. Musical creativity is a complex phenotype where a common background with musicality and intelligence has been proposed. Here, we implicate genetic regions affecting music-related creative behaviour, which also include genes with neuropsychiatric associations. We also propose a common genetic background for music-related creative behaviour and musical abilities at chromosome 4.
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Affiliation(s)
- Jaana Oikkonen
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Tuire Kuusi
- Sibelius Academy, University of the Arts Helsinki, Helsinki, Finland
| | - Petri Peltonen
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | | | - Liisa Ukkola-Vuoti
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | - Kai Karma
- Sibelius Academy, University of the Arts Helsinki, Helsinki, Finland
| | - Päivi Onkamo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
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Gingras B, Honing H, Peretz I, Trainor LJ, Fisher SE. Defining the biological bases of individual differences in musicality. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140092. [PMID: 25646515 DOI: 10.1098/rstb.2014.0092] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Advances in molecular technologies make it possible to pinpoint genomic factors associated with complex human traits. For cognition and behaviour, identification of underlying genes provides new entry points for deciphering the key neurobiological pathways. In the past decade, the search for genetic correlates of musicality has gained traction. Reports have documented familial clustering for different extremes of ability, including amusia and absolute pitch (AP), with twin studies demonstrating high heritability for some music-related skills, such as pitch perception. Certain chromosomal regions have been linked to AP and musical aptitude, while individual candidate genes have been investigated in relation to aptitude and creativity. Most recently, researchers in this field started performing genome-wide association scans. Thus far, studies have been hampered by relatively small sample sizes and limitations in defining components of musicality, including an emphasis on skills that can only be assessed in trained musicians. With opportunities to administer standardized aptitude tests online, systematic large-scale assessment of musical abilities is now feasible, an important step towards high-powered genome-wide screens. Here, we offer a synthesis of existing literatures and outline concrete suggestions for the development of comprehensive operational tools for the analysis of musical phenotypes.
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Affiliation(s)
- Bruno Gingras
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
| | - Henkjan Honing
- Amsterdam Brain and Cognition (ABC), Institute of Logic, Language and Computation (ILLC), University of Amsterdam, Amsterdam, The Netherlands
| | - Isabelle Peretz
- International Laboratory for Brain, Music and Sound Research, Department of Psychology, University of Montreal, Quebec, Canada
| | - Laurel J Trainor
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Ontario, Canada
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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