Our brain neurones communicate with one another with chemical and electric signals. The chemical signals are influencing the reaction of neurones to electrical signals so are quite important but to decode what a brain is "thinking" (like let's move this finger....) electrical signals will do.
Hence the work of many researchers to find ways of intercepting and decoding these signals. There is so much electrical activity going on that the closer you are to the place where a signal is generated/received the easier it is to single it out of the millions percolating in the whole brain at any single moment.
The progress in signal processing is now allowing the detection of specific signals using a sort of "hat" (BCI) one person can wear, equipped with tens/hundreds of sensors. To get more precise data, however, one would need to insert electrodes, probes, inside the brain making a hole in the skull and positioning the electrode in the right place. This is surely not fun and besides it has great technical difficulties, as I pointed out in several innovations regarding electrodes implants in some of these posts.
This is why this news coming from Melbourne University is so interesting.
Researchers have created a stent that works as an electrode (stentrode). It can be inserted inside a blood vessel in the brain (using a procedure that access the brain through an artery in the leg and pushing the stent up to the aorta and from there through the carotid artery into the brain). The stent is just 3mm wide and can be positioned in several places inside the brain, in particular reaching the motor control areas. By capturing the signals inside the brain they provide much more accurate data leading to more effective interpretation.
The procedure is not easy but it is feasible and has the advantage that the stent will remain in place for as long as needed monitoring the electrical activity in that specific area. Data are communicated to an external receiver that will relay them to a computer for processing.
The foreseen application is to control an exoskeleton enabling paralysed patients to move their limbs again.