Researchers at the Université de Genève are exploring how a common language of the senses facilitates our integration of sensory information.
Sight, touch and hearing operate on sensory channels that send a constant flow of information to the brain, which acts to sort out and integrate these signals, allowing us to perceive the world and interact with our environment. Neuroscientists at Université de Genève (UNIGE) wanted to determine how these sensory pathways emerge during development. Do they share a common structure, or do they emerge independently, each with specific features? By identifying gene expression signatures common to hearing, sight and touch, the University of Geneva team discovered a sensory “lingua franca,” or common language that facilitates the brain’s interpretation and integration of all sensory input. The study results, published in the September 26, 2016 edition of Nature, pave the way towards a better understanding of perception and communication disorders.
Researcher Denis Jabaudon, PhD, UNIGE Faculty of Medicine, and co-investigators report that the ability to detect and sort various kinds of stimuli is essential to interacting with surrounding objects and people, and to communicating correctly. Indeed, social interaction deficits in people living with autism appear to be partly due difficulties in detecting and interpreting sensory signals. But how does the brain interpret and integrate the stimuli sent by our five senses? This is the essential question that Jabaudon and his co-authors addressed.
“We studied the genetic structure of tactile, visual and auditory pathways in mice,” said Laura Frangeul, the first author on the study paper. “By observing neuronal gene expression in these distinct pathways during development, we detected common patterns, as if an underlying genetic language was bringing them together.”
A Common Language of the Senses
The neuroscience study team‘s results reveal that during development, the various sensory pathways initially share a common gene expression structure, which then adapts to the activity of the organ attached to each sense. “This process only takes a few days in mice, but could take up to several months in human beings, whose development is much longer and very sensitive to the environment,” said Jabaudon in a recent announcement from UNIGE.
This genetic ‘lingua franca’ allows the various sensory pathways to be built according to a similar architecture regardless of their very different functions. According to the authors, it is this shared language that allows the brain to accurately interpret stimuli coming from different sources, and to compose a coherent representation of their combined meaning.
Sharing the same structure also explains how various pathways can mutually balance out, say the authors, as when touch or hearing become highly over-developed in people born blind. This discovery also explains why sensory interferences, including synesthesia and hallucinations, can occur in people suffering from disorders such as autism or schizophrenia.
The study authors say their findings allow a better understanding of how the brain circuits which build our representation of the world assemble during development, and help to could potentially be put to use to repair the circuits when they fail.
Source: Université de Genève
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