The role of synaesthesia in reading written musical key signatures.

This study is the first empirical demonstration of synaesthesia for reading written musical keys signatures. Nine music-color synaesthetes and 9 controls took part in 5 experiments that aimed to confirm the authenticity of synaesthesia for reading musical keys, and to demonstrate that this type of synaesthesia is linked to conceptual rather than to purely perceptual processing of the inducing stimulus. First, the existence of a synaesthetic association with written musical keys was validated in an objective manner by employing 2 measures of consistency as diagnostic criteria. Second, the automaticity of the synaesthetes' responses was tested by demonstrating the presence of interference when naming synaesthetic colors for incongruent pairings of color and musical key. To test whether a change in form altered the concept of the musical key, stimuli were randomly presented in 3 separate modes (words, treble clef, or bass clef). Last, the interference of synaesthetic colors with veridical colors was assessed in a task-irrelevant manner, that is, without the need for the explicit naming of synaesthetic color. Findings showed synaesthesia for written musical keys to be a genuine form of synaesthesia elicited from the concept, or the idea, of the key. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Genes, brain dynamics and art: the genetic underpinnings of creativity in dancing, musicality and visual arts.

Creativity, art and artistic creation in music, dance and visual arts are brain activities specific to humans. Their genetic background remained unexplored for years, but many recent studies have uncovered significant associations with cognition-related genes and loci. These studies are summarized in the present article. Creativity is a trait with heavy genetic influences, which are also associated with mental disorders and altruism. Associated genes include dopaminergic, serotoninergic and other genes (a1-antitrypsin, neuregulin, Brain-derived neurotrophic factor). Music is another complex phenotype with important genetic background. Studies in musicians and their families have highlighted the contribution of loci (e.g., 4q22) and specific genes (vasopressin receptor 1α and serotonin transporter). The latter two are also associated with dancing. Although few studies have investigated visual arts, they appear to be influenced by genetic differences, which could explain the increased prevalence of synesthesia in artists and individuals with autism. Lastly, although genes play an important role in creativity and art, epigenetics and the environment should not be overlooked. The genetic exploration of artistic creativity may provide useful knowledge on cognition, behavior and brain function. It may also enable targeted and personalized art therapy in health and disease.

Investigating genetic links between grapheme-colour synaesthesia and neuropsychiatric traits.

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'.