IEEE Future Directions
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We are making good progress in identifying neural circuits in our brain, small areas responsible for the execution of specific tasks. It is not always the case, actually several tasks are involving many areas in different regions of the brain. Also in this case, however, specific regions host neural circuits whose activity spread around influencing other neural networks.
The malfunctioning of these “networks” results in disabilities and the good news is that researchers are starting to find ways to restore (in some cases) the correct working of these neural circuits using drugs.
The problem, however, is that these drugs cannot be delivered through the blood vessels since they would reach “the whole brain” and what is good for a “faulty” circuit may be bad for a “good” circuit. Besides, many drugs cannot flow across the membrane separating the arteries and veins from the brain (the so called blood-brain barrier). This obstacle is exploited by new technologies based on ultrasound beams that can be focussed in a specific place of the brain resulting in the opening of the blood vessels membrane in that area thus letting the drug reach the neurones. This is great but in mot cases it is not enough because the area “flooded” by the drug is still quite large (on a neuronal scale).
Here comes the result from researchers at MIT that have created a way to deliver nanoliter of drugs to areas as small as a cubic millimetre. Again, on the neural scale a cubic millimetre is … well, huge: it contains some 50,000 neurones and 300 million synapses! It is anyhow so much smaller than the area that would be affected by a drug delivered through a blood vessel (even the one that creates a breach into the blood brain barrier), hence it can target much better the faulty circuit without too much effects on other nearby circuits.
The researchers have developed a micro tube (cannulas), 30 µm in diameter, as thin as a human hair, that is inserted in the right spot using a 150µm steel needle. The cannulas contains nano-pumps that can deliver nano litre of drugs as required. In addition the cannulas can also contain a micro electrode to sense electrical activity and monitor the effect of the drug.
We can expect amazing progress in the next decade fuelled by the convergence of technology and knowledge, each one leveraging on the other.
