• Joseph Diong

A tiny peek at brain reading devices

Recently, a cute little pig called Gertude made headlines around the world. It was brought into a pen, sniffed its surroundings as Elon Musk looked on. The twist? This pig had an implant in its brain for 2 months.

Its brain activity measured and displayed in real time as it explored the room. Elon Musk hopes that with this development, science fiction might come to life, using this invention to grant users “conceptual telepathy”, communicating electronically without speaking.

Elon Musk illuminates to the world what has been in development for more than a decade, the technology to interface directly with the brain and retrieve new sorts of information from it. Directly interacting with the brain could possibly lead to faster reaction times and allow us to control machines and tools. This is especially exciting for paraplegics and quadriplegics, who may one day be able to regain control of their limbs with this technology.

The term for this is “brain machine interface” or BMI. It is defined as a machine that allows direct communication between the brain and a device. This device would usually pick up on a cell in our brain called a neuron when it creates an electrical impulse. The pattern would be picked up by the device and sent out to sensors outside, where the pattern will be decoded by the sensor and translated into something useful, such as telling the right arm to move to the left.

Some devices are big and clunky and require invasive procedures to open the scalp, potentially causing harm to the patient as the device attaches to the brain. Other devices require insertion into the scalp, left on the membrane of the brain without touching the brain directly. The device discussed in this article is about a device coined as “neural dust”.

Neural dust is not composed of a single component; rather, salt grained sized particles called nodes that are embedded on the brain, hence the name “dust”. These particles pick up signals from the neurons in the brain by measuring difference in electric potentials, recording the differences. The recorded differences are then sent to the external sensor through the skull and decoded. The signal must be decoded as there may be attenuation, a fancy word for interference affecting the quality of the signal as it passes through objects in space, in this case the skull. The dust is powered by ultrasound, which causes a piezoelectric crystal in the node to create voltage, generating electricity.

There are other alternative devices out there that can record brain signals, albeit with limitations. Power consumption is a major factor, as the amount of power required to send signals through the brain and outside is relatively significant to the size of devices implanted in the brain. It may create restrictions on movement and portability due to the size of power sources. Another is materials that are biocompatible, not inciting a potentially fatal immune response to the foreign object. The days of mind reading may be still far off, but hopefully with advances in technology we may be able to create prosthetics that can mimic the functionality and practicality of a real arm.

Source: D. Seo, J. Carmena, J. Rabaey, E. Alon and M. Maharbiz, "Neural Dust: An Ultrasonic, Low Power Solution for Chronic Brain-Machine Interfaces", arXiv.org, 2020. [Online]. Available: https://arxiv.org/abs/1307.2196. [Accessed: 31- Aug- 2020].