The Brain: The Story of You

by David Eagleman

Four methods to push visual information to the brain through unusual sensory channels: the lower back, the ears, the forehead, and the tongue.

If it sounds crazy to “see” through your tongue, just keep in mind that seeing is never anything but electrical signals streaming into the darkness of your skull. Normally this happens via the optic nerves, but there’s no reason the information can’t stream in via other nerves instead. As sensory substitution demonstrates, the brain takes whatever data comes in and figures out what it can make of it.

In the distant future, we won’t just be extending our physical bodies, but fundamentally our sense of self. As we take on new sensory experiences and control new kinds of bodies, that will change us profoundly as individuals: our physicality sets the stage for how we feel, how we think, and who we are.

We’re already beginning to extend the human body, but no matter how much we enhance ourselves, there is one snag that’s difficult to avoid: our brains and bodies are built of physical stuff. They will deteriorate and die. There will come a moment when all your neural activity will come to a halt, and then the glorious experience of being conscious will come to an end. It doesn’t matter who you know or what you do: this is the fate of all of us. In fact, it’s the fate of all life, but only humans are so unusually foresighted that we suffer over this knowledge.

For the past fifty years, the Alcor Life Extension Foundation has been developing technology they believe will allow people living today to enjoy a second life-cycle later. The organization currently stores 129 people in a deep freeze that halts their biological decay.

cryopreservation

The typical brain has about eighty-six billion neurons, each making about ten thousand connections. They connect in a very specific manner, unique to each person. Your experiences, your memories, all the stuff that makes you you is represented by the unique pattern of the quadrillion connections between your brain cells. This pattern, far too large to comprehend, is summarized as your “connectome”.

to store a high-resolution architecture of a single human brain would require a zettabyte of capacity. That’s the same size as all the digital content of the planet right now.

With every attempt to simulate or create a human-like intelligence, we’re confronted by a central unsolved question of neuroscience: how does something as rich as the subjective feeling of being me – the sting of pain, the redness of red, the taste of grapefruit – arise from billions of simple brain cells running through their operations? After all, each brain cell is just a cell, following local rules, running its basic operations. By itself, it can’t do much. So how do billions of these add up to the subjective experience of being me?

A mill has mechanically interacting pieces and parts, but one wouldn’t be tempted to propose that the mill thinks. So where does the magic occur in the brain, which is also made of pieces and parts?

When we look inside the brain, we see neurons, synapses, chemical transmitters, electrical activity. We see billions of active, chattering cells. Where are you? Where are your thoughts? Your emotions? The feeling of happiness, the color of indigo blue? How can you be made of mere matter? To Leibniz, the mind seemed inexplicable by mechanical causes.