The genetics of colored sequence synesthesia: suggestive evidence of linkage to 16q and genetic heterogeneity for the condition.
ABSTRACT Synesthesia is a perceptual condition in which sensory stimulation triggers anomalous sensory experiences. In colored sequence synesthesia (CSS), color experiences are triggered by sequences such as letters or numbers. We performed a family based linkage analysis to identify genetic loci responsible for the increased neural crosstalk underlying CSS. Our results implicate a 23 MB region at 16q12.2-23.1, providing the first step in understanding the molecular basis of CSS.
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Chapter: What synesthesia isn't[Show abstract] [Hide abstract]
ABSTRACT: Synesthesia is a condition in which a particular sensory stimulus (or even the thought of that stimulus) — the inducer — reliably elicits not only the normal perceptual experience but also some additional, inappropriate sensation—the concurrent. In the earliest known reference to this phenomenon, John Locke (1690) described a blind man who, when asked to describe the color scarlet, replied that it is " like the sound of a trumpet. " Indeed, the commonest forms of synesthesia involve seeing colors when listening to sounds or words, or reading letters or numbers. Like schizophrenia and dementia, synesthesia is oft en described as a singular phenotype. Th e implication is that this extraordinary condition is a well-defi ned " pathological " form of perception with a distinct neurological basis. However, like schizophrenia and dementia, convenient terminology and minimal defi nition might hide a variety of conditions, with diff erent etiologies and manifestations. In this chapter we question the defi nition of synesthesia, its proposed causes and neurological underpinnings; whether it takes one or many forms, and whether it is a highly aberrant condition or merely the extreme end of a continuum of perceptual function. Despite the fl urry of research on synesthesia in the past 20 years, aided by the advent of neuroimaging, many of these fundamental issues remain unresolved. We are left with more certainty about what synesthesia is not, than about what it is. Problems With the Definition of Synesthesia Any serious study of an unusual phenotype depends on the clarity of its description: but there is still ambivalence and debate about the essential criteria that defi ne synesthesia. Early descriptions of the phenomenon, which was then usually called " hyperchromat-opsia " (" hyperchromatopsie " in French), emphasized the vivid nature of the concurrent experiences, which were oft en described as illusions or hallucinations (see Jewanski et al. 2011). It was not until the late nineteenth century that Heinrich Kaiser (1872) described OUP UNCORRECTED PROOF – FIRSTPROOFS, Wed May 29 2013, NEWGENThe Oxford Handbook of Synaesthesia, Edited by J Simner, E Hubbard, 01/2013: pages 959-988; Oxford University Press.
- Frontiers in Psychology 01/2015; 6:54. · 2.80 Impact Factor
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ABSTRACT: INTRODUCTION. Synesthesia is a neural phenomenon in which stimulation in one sensory or cognitive stream leads to associated experiences in a second, unstimulated stream. These activations occur involuntarily, automatically and consistently over time. AIM. To estimate the relative frequency of the different modalities of the phenomenon in a Spanish sample. SUBJECTS AND METHODS. Study performed in educational (55.04%), labor (20.54%) and digital contexts (24.4%) using the Synesthesia Questionnaire created by Artecitta Foundation. RESULTS. The analysis of the responses given by 803 participants suggests that 13.95% of the sample experience any synesthesia. The analysis of the relative frequencies shows that the most frequent modality is spatial sequence synesthesia (44.6%). 33.9% see colors when listening to sounds and/or music, 25.9% associate colors to temporal concepts, 20.5% assign gender and personality to letters and numbers, 10.7% experience grapheme-color synesthesia and 5.4% feel a specific flavor when hearing words. CONCLUSIONS. These data suggest that the presence of synesthesia in the Spanish sample under study is high, and that the investigation of the phenomenon and its different modalities needs to be approached on the basis of the current knowledge about its phenomenological variability and its genetic and neurophysiologic characteristics. Likewise, the results are useful to adjust the questionnaire items and increase their discriminative power.Revista de neurologia. 02/2015; 60(4):145-50.