I’ve got a feeling

Roberto Saracco July 19, 2018 Blog 720 Views

Illustration of an artificial afferent nerve system made of pressure sensors, an organic ring oscillator (simulates a neuron), and a transistor that simulates a synapse. (Only one ring oscillator connected to a synaptic transistor is shown here for simplicity.) Colors of parts match corresponding colors in the biological version. Credit: Yeongin Kim (Stanford University), Alex Chortos (Stanford University), Wentao Xu (Seoul National University), Zhenan Bao (Stanford University), Tae-Woo Lee (Seoul National University)

A collaboration among researchers at Stanford and Seoul National University has resulted in the creation of an artificial sensory nerve. A sensory nerve is a complex entity, part of the somatosensory system, that is able to integrate different physical stimuli into a tactile information. Our sense of touch generate data about temperature, pressure, surface characteristics (including dry and wet…) that in turns our brains convert into perception of the physical reality.

Being able to integrate all these different characteristics has been a major challenge so far. We have temperature sensors, pressure sensors, movement sensors but we did not have an integration of them all so it has been impossible so far to create an artificial skin functionally equivalent, from a tactile point of view, to our skin.
This has been a major issue for the creation of seamless prosthetics as well as for creating robots having our “touch”.

The research collaboration has resulted in the integration of pressure sensors, a flexible electronic neurone and an artificial synaptic transistor mirroring the functionality of a human synapses.

As it happens with afferent nerves (those that are relaying information to the brain from the periphery, like tactile information), a first integration occurs at he level of the nerve. like the syntheses of tactile data provided by pressure sensors.

Additionally, the structure allows for local feedback, as it happens with natural sensorial nerves (if you touch something hot the reflex action of removing your hand from the hot surface is not the result of a brain processing, rather it happens at the spinal level where afferent nerves are connected to motor nerves, thus ensuring a much faster reaction). This local reflex capability was shown by connecting the artificial nerve to a cockroach leg and showing that certain “sensations” results in signals to the leg and its movement.

The results will be applied to human prosthetics taking one more step towards real symbioses between humans and artefacts, as well as to robots augmenting their capabilities to interface with their environment. It is another example of a technology evolution that fosters the progress towards symbiotic autonomous systems, applicable to both humans and machines and narrowing the gap between them.