Seeing sounds: Researchers uncover molecular clues for synesthesia

March 5, 2018, Max Planck Society
Credit: CC0 Public Domain

One in 25 people have synesthesia, in which an experience involving one sense is associated with perception in another sense—for example, seeing colors when listening to music. Now, researchers at the Max Planck Institute for Psycholinguistics and the University of Cambridge report clues into the biological origins of such variations in human perception. They studied families with synesthesia, and describe genetic changes that might contribute to their differences in sensory experience.

Some people with may see sounds, while others may taste them or feel them as shapes. This kind of sensory cross-talk comes in many forms, and develops during early childhood. It has been known for over a century that synaesthesia runs in families, giving a strong hint that inherited factors are important.

"Brain imaging of adults with synaesthesia suggests that their circuits are wired a little differently compared to people who don't make these extra sensory associations. What we don't know yet is how these differences develop," said Dr. Amanda Tilot, a geneticist at the Max Planck Institute for Psycholinguistics. "We suspect some of the answers lie in people's genetic makeup."

A genetic window into sensory experience

Today, in a report published in the journal Proceedings of the National Academy of Sciences, scientists from the Max Planck Institute for Psycholinguistics and the University of Cambridge report new genetic clues that could help explain the biology of synaesthesia. The researchers carefully analysed the DNA of three families in which multiple members, across several different generations, experience colour when listening to sounds.

The team took advantage of advances in genome sequencing, enabling them to identify genetic variants in the synaesthesia families and track how they were passed on from one generation to the next. In particular, they focused attention on rare DNA changes that altered the way genes code for proteins, and that perfectly matched the inheritance of synaesthesia in each of the three families.

While the highlighted DNA variants differed between the three families, a common theme emerged to connect them: an enrichment for genes involved in axonogenesis and cell migration. Axonogenesis is a key process enabling brain cells to wire up to their correct partners.

Combining families to uncover biological processes

Professor Simon Fisher, Director of the Max Planck Institute, who led the research, said, "We knew from earlier studies by the Cambridge team that no single gene can account for this intriguing trait; even families who experience the same form of synaesthesia are likely to differ in terms of specific genetic explanations," said Fisher. "Our hope was that the DNA data might point to shared as candidates for involvement in synaesthesia."

Professor Simon Baron-Cohen, Director of the Autism Research Centre, Cambridge University, commented, "This research is revealing how genetic variation can modify our sensory , potentially via altered connectivity in the brain. Synaesthesia is a clear example of neurodiversity which we should respect and celebrate."

In search of synaesthetes

To better understand these findings, the team is looking for new families and individuals to join their study. To learn more about their research and take a short test to find out if you experience a common form of synaesthesia, go to http://www.mpi.nl/synaesthesia.

Explore further: Synaesthesia is more common in autism

More information: Amanda K. Tilot el al., "Rare variants in axonogenesis genes connect three families with sound–color synesthesia," PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1715492115

Related Stories

Synaesthesia is more common in autism

November 19, 2013
People with autism are more likely to also have synaesthesia, suggests new research in the journal Molecular Autism.

Scientists pinpoint sensory links between autism and synesthesia

March 7, 2017
Concrete links between the symptoms of autism and synaesthesia have been discovered and clarified for the first time, according to new research by psychologists at the University of Sussex.

Researchers induce a form of synesthesia with hypnosis

December 14, 2017
Hypnosis can alter the way certain individuals information process information. A new phenomenon has been identified by researchers from the University of Skövde in Sweden and the University of Turku in Finland. They have ...

Recommended for you

Thousands of unknown DNA changes in the developing brain revealed by machine learning

September 24, 2018
Unlike most cells in the rest of our body, the DNA (the genome) in each of our brain cells is not the same: it varies from cell to cell, caused by somatic changes. This could explain many mysteries—from the cause of Alzheimer's ...

Mitochondrial diseases could be treated with gene therapy, study suggests

September 24, 2018
Researchers have developed a genome editing tool for the potential treatment of mitochondrial diseases: serious and often fatal conditions which affect 1 in 5,000 people.

How to edit your mitochondria

September 24, 2018
Mitochondrial genetic engineering is the adaptation of genetic engineering techniques to specific mitochondrial problems. Although it is not common to be born with severe mitochondrial issues, we will all eventually have ...

Height may be risk factor for varicose veins, study finds

September 24, 2018
The taller you are, the more likely you are to develop varicose veins, according to a study led by Stanford University School of Medicine researchers that examined the genes of more than 400,000 people in search of clues ...

Researchers identify new genetic disorder

September 21, 2018
Researchers from Michigan State University College of Human Medicine and physicians from Spectrum Health have identified for the first time in a human patient a genetic disorder only previously described in animal models.

Test could detect patients at risk from lethal fungal spores

September 20, 2018
Scientists at The University of Manchester have discovered a genetic mutation in humans linked to a 17-fold increase in the amount of dangerous fungal spores in the lungs.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.