Human skin behaves like a memristor

Human skin behaves like a memristor

A group of physicists from the University of Oslo found that human skin can behave like a memristor.

It is customary to call memristors passive elements that establish the relationship between the time integrals of the current flowing through them and the voltage across them. The first working sample of such an element was obtained three years ago by HP employees based on a thin film of titanium dioxide.

It is known that memristors very successfully mimic the properties of synapses: the serial connection of two correctly selected elements makes it possible to simulate the transmission of nerve impulses in the body. In the future, memristors may become the basis for so-called neuromorphic systems, which are designed taking into account the architecture of the nervous system.

Looking through the archived data of experiments, the authors found a simpler example of natural “memristiveness”. It turned out that ordinary skin has corresponding characteristics: the application of a negative potential increases its electrical conductivity, while a positive potential acts in the opposite way, increasing the skin’s resistance in subsequent experiments. In other words, its electrical properties depend on the currents flowing earlier.

The researchers believe the reason for this is the action of sweat pores. Sweat contains ions with a positive electrical charge (say, sodium ions), and the application of a potential causes the liquid in the cylindrical air to move up or down. In the case of negative potential, highly conductive sweat rises, gradually decreasing resistance until the pore is full. On the other hand, a positive potential reduces the thickness of the liquid layer on the pore walls and the electrical conductivity of the skin.

Action of negative and positive potentials (illustration by NewScientist).

Prepared based on the materials of “Computerra”

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