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Book Summary: The Brain- The Story of You

Author: David Eagleman

Substory: Brain Plasticity

We’ve become progressively better at plugging machinery directly into our bodies. You may not realize it, but currently hundreds of thousands of people are walking around with artificial hearing and artificial vision.

With a device called a cochlear implant, an external microphone digitizes a sound signal and feeds it to the auditory nerve. Similarly, the retinal implant digitizes a signal from a camera, and sends it through an electrode grid plugged into the optic nerve at the back of the eye. For deaf and blind people around the planet, these devices have restored their senses.

It wasn’t always clear that such an approach would work. When these technologies were first introduced, many researchers were skeptical: the brain is wired up with such precision and specificity that it wasn’t clear there could be a meaningful dialog between metal electrodes and biological cells. Would the brain be able to understand crude, non-biological signals, or would it be confused by them?

As it turns out, the brain learns to interpret the signals. Getting used to these implants is a bit like learning a new language for the brain. At first the foreign electrical signals are unintelligible, but the neural networks eventually extract patterns in incoming data. Although the input signals are crude, the brain finds a way to make sense of them. It hunts for patterns, cross-referencing with other senses. If there’s structure to be found in the incoming data, the brain ferrets it out – and after several weeks the information begins to take on meaning. Even though the implants give slightly different signals than do our natural sense organs, the brain figures out how to make do with the information it can get.