Neuroscientists at the University of New South Wales (UNSW), Sydney, Australia, have discovered a new understanding of how the brain deciphers neural inputs, which could transform the next generation of prosthetic devices. The findings represent a new way of looking at how our brains make judgements about the environment, and could help researchers build better brain-machine interfaces and haptic devices. The UNSW scientists are exploring the possibility of developing a method to be used to restore a sense of touch in amputees. It is expected that by manipulating timing of electrical impulse generation in the nerve, it will be possible to make people feel varied tactile sensation.
Neurophysiologists Ingvars Birznieks, PhD, and Richard Vickery, PhD, in the UNSW School of Medical Sciences, research the sense of touch and how human beings get information such as pressure, shape, texture, and vibration from one signal. Seven years ago, they began working with a pin array device called an optacon (optical to tactile converter). Designed to stimulate the fingertip, the device has 144 tiny pins which move very fast. When moved over text, for example, the pins move in sync with the letters, allowing a person with sight to teach a blind person to read.
“A unique unintended feature of this device is that one tap of the pin can generate a single electrical impulse in touch neurons,” said Vickery. “These impulses are what neurons use to communicate, so we could use it to interrogate the nervous system.”
Birznieks and Vickery were able to send a stream of code with whatever information they wanted. “We could talk to the brain using its own language and see how it interprets the messages we sent to it. Using this dialog we were in a position to learn the brain’s language or neural code,” Birznieks said.
According to the researchers, they found the brain uses periods of “quiet” between the impulses to make judgements about the environment, which flies in the face of the conventional view that says neural activity is the main driver of human perception.
Birznieks said the work has transformed the understanding of basic principles how our brains encode information.
“We expect this will rewrite the textbooks,” he said.
The paper, “Spike timing matters in novel neuronal code involved in vibrotactile frequency perception,” was published online May 4 in Current Biology.
Editor’s note: This story was adapted from materials provided by UNSW.