Scientists develop new understanding of touch

An international group of researchers, part-funded by the European Research Council, have linked a group of neurons to a specific type of somatosensation, a finding that can open the door for a heightened understanding about our sense of touch.

The research was led by Alison Barth, professor of biological sciences, of Carnegie Mellon University in Pittsburgh, USA. Somatosensation, which describes the sense of touch, occurs in a number of forms, like feeling texture, temperature, pressure, pain or vibration and is responsible for proprioception. Whilst scientists understand the molecular receptors that mediate the different types of somatosensation, little is known about how touch is represented in the brain.

Speaking about the research, Barth said: “Somatosensation is critical. You can somewhat overcome losing your sense of smell, sight, taste, or hearing, yet if you lose your sense of touch, you wouldn’t be able to sit up or walk; you wouldn’t be able to feel pain. We know less about the features that make up our rich tactile experience than we do about any other sense, yet it’s such a critical sense.

“This is the first time we’ve been able to visualise neurons in the somatosensory cortex that ‘like’ a specific tactile stimulus. It shows that neurons are individuals. They have different jobs to do in the cortex. In this case these neurons had a special feature: they responded when all of the mouse’s whiskers moved at once.”

Undertaking research using a transgenic mouse model to assess activity in live neurons, researchers also discovered that neurons received direct synaptic input from the posteromedial nucleus of the brain’s thalamus. This shows that the neurons that react to the puff-of-air stimulus have a dedicated, unique sub-network of connections that enable them to communicate with one another and amplify the information they are receiving from the stimulus.

It is hoped that the research could lead to further studies that will identify how somatosensory information is coded, which could be used to incorporate sensory information into brain-machine interfaces. This could allow robotic limbs and prosthetics to actively sense and receive tactile input.

The research is published in the journal Neuron.