Interacting with neurons

Zinc oxide is both optically transparent and able to conduct electricity. The material made it possible to make a device (enlarged image above) that could both stimulate brain activity with light and record activity in multiple neural microcircuits at the same time. Credit: Nurmikko Lab / Brown Univeristy

Ten years ago, in 2005, scientists discover the possibility of modifying neurones in a brain in such a way that they can produce light sensitive molecules on the neurone membrane. When these proteins are hit by a beam of light they affect the behaviour of the neurone. 
Optogenetics was born and with it an effective way to interact with the brain at neuronal level (rather than with drugs that are not selective and affect the whole brain).

The monitoring at neuronal level is also possibile using implanted micro electrodes but so far it has not been possibile to monitor at neurone level the effect of an optogenetic signal because the probe used to illuminate the neurone(s) could not be associated with an electrode. The spatial distance required between the two is two big to provide a feedback.

Now researchers at Brown University have managed to create a system that embeds in the same probe also the electrode. They built a 4x4 probe made by zinc oxide, a transparent metal that can be used to both transport and emit light and to detect electrical activity. The probe is just a few square mm and contains 16 spikes that can operate independently one another providing micrometer precision. It becomes possible to detect the behaviour of single neurones or single neuronal circuits.

They plan to insert hundreds of them on the cortical cortex of primates to have the first detailed understanding of optogenetics effects. The goal is to be able to condition neural activities in human brain affected by some pathologies for cure. This might become possible in the next decade.

For the time being the goal is to have a leap in our understanding of the brain.

Author - Roberto Saracco

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