Usage of light signals to establish communication between artificial neurons
In the famous Hollywood movie “Harry Potter” the character Alastor Moody’s “Mad-Eye” as well as his “prosthetic leg” creates fear in the minds of viewers. We could see a similar aid in “Pirates of the Caribbean” where Hector Barbossa uses a “wooden leg” in the place of his lost leg. The major antagonist in the Malayalam movie “Nirnayam” is a one-handed man where his other hand is replaced by artificial metal implants. Whether it is Elijah Wood, from “The Lord of the Rings” or “Cyborg” the list of characters in movies who had used artificial body parts just keeps growing. With the advent of science and technology, the replacement of body parts and organs is possible and these artificially replaced parts are termed as prosthetics. What would happen if our brain has damage, did anyone ever thought of this? Well, a group of researchers interested in neuroprosthetics is working currently on this project.
As everyone knows, the human brain has a very complex structure, consisting of approx 86 billion neurons. The precise communication between these neurons enables us to control all our body movements as well as the decisions made by our conscious mind. Ikerbasque Researcher Paolo Bonifazi from Biocruces Health Research Institute (Bilbao, Spain), and Timothée Levi from the Institute of Industrial Science, The University of Tokyo, and from IMS lab, University of Bordeaux and their leading international team is creating neuroprosthetics which could replace the neurons in our brain.
But this is not an easy task, creating identical neurons as well as managing the transmission and acceptance of the signals managing its synchronous nature, is indeed a herculean task. The team had been successful in recreating identical neurons but a major problem remained unsolved, the signals transmitted should be quick enough to reach the destined neuron in split seconds. The electric output from electronic parts failed to achieve this goal. So searching a better option left no other choice than the use of light signals for the transmission of impulses. For that, the electric signals generated is transferred into optical signals. This had become possible due to the recent developments in optogenetics which takes advantage of specific abilities of some proteins from algae and other beings.
In order to achieve this, task-specific protein should be taken and inserted in the respective cells. Here for the specific purpose proteins which were activated by blue light were isolated by the group and the electrical output of the spiking neuronal network is channelled to checked blue and black squares of proteins. They had used a projection of this pattern down on to 0.8 by 0.8 mm square of a dish containing the biological neuronal network and only the light from the blue squares activated the neurons.
The spontaneity of this process increases with the rhythmic impulses and which in turn depends on the structure of the neuronal network.
According to Timothée Levi from IIS “The key to our success, was understanding that the rhythms of the artificial neurons had to match those of the real neurons. Once we were able to do this, the biological network was able to respond to the “melodies” sent by the artificial one. Preliminary results obtained during the European Brainbow project, help us to design these biomimetic artificial neurons.”
From different patterns, they were able to identify the best matches required for their purpose. Levi also added, “The light patterns were shown onto a very small area of the cultured neurons, and the researchers were able to verify local reactions as well as changes in the global rhythms of the biological network. Incorporating optogenetics into the system is an advance towards practicality. It will allow future biomimetic devices to communicate with specific types of neurons or within specific neuronal circuits”
The team is looking forward to the future where damaged brain cells would be replaced and the broken communication could be easily restored by the use of their prosthetic. 🙂
In the University of Tokyo, in collaboration with Dr Kohno and Dr Ikeuchi, they are focusing on designing bio-hybrid neuromorphic systems to create a new generation of neuroprosthesis. This research could be a major milestone in scientific history.
-Krupa V. Mathew
Journal reference: Nature, “Toward neuroprosthetic real-time communication from in silico to the biological neuronal network via patterned optogenetic stimulation,” was published in Scientific Reports at DOI: 10.1038/s41598-020-63934-4.
Institute of Industrial Science, The university of tokyo
Further Reading : Brain shuts down Pain!! https://shasthrasnehi.com/amygdala-the-pain-controlling-region-of-brain/
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