Why I Wrote a Book About Spikes
It’s how your brain works, after all
Neurons. Over the deep time of Earth’s history, these tiny bags of chemicals have joined forces, swarming together in gargantuan numbers, all to make a brain. In cahoots, these neurons do everything you do: sense, think, move; sleep, dream, and cogitate. Eat cake. Watch telly. Eat cake and watch telly, while ruminating on the possible locations of the biscuits you swore you bought two days ago.
Knowing ourselves means knowing our neurons. That one bunch of neurons are active at the exact same time is how you reach for your phone without knocking over your cup. The simultaneous activity of a different bunch of neurons is how you see your phone in the first place. For yet another collective of neurons, their activity is your irrational fear of blue zebras. And for another, it is how you know you are lost, literally or figuratively.
That “activity” is the tiny electrical pulses, the spikes, passed between your brain’s neurons. These spikes are the brain’s own language, ceaselessly traversing your brain from before you were born until your final moment. Your life is lived in spikes.
Yet no one has ever written a book about spikes for everyone.
My new book, The Spike: An Epic Journey Through the Brain in 2.1 Seconds, changes all that: it will tell you the story of the spike’s journey, of everything we know about how it passes through your brain, what it sees on the way, and what it means.
I wrote this book because it is sorely needed. Popular accounts of neuroscience have told us much about the broad picture, of how a group of brain areas may process vision, but not hearing; create emotional responses to faces, but not chocolate; or paradoxically only turn on when your mind goes blank. Many of these accounts rely on neuroimaging, especially functional MRI (fMRI). Each tiny pixel on an fMRI image, each dot of colour, contains 100,000 neurons. fMRI measures the flow of oxygen-rich blood around those 100,000 neurons, a flow that increases as those 100,000 neurons send more spikes, for making spikes needs energy, and creating energy needs oxygen. Each dot of colour shows us only where the demand for such energy-giving blood has changed around 100,000 neurons. So fMRI cannot see or record individual neurons, let alone the spikes emitted from them.
It is a wonderful technology, the only way to peer at the moment-to-moment activity inside the living human mind. But alone it is of no use to us who want to know about what neurons are doing. Trying to understand how neurons work using fMRI is like trying to follow a football match through the roar of the crowd. The crowd’s crescendos and groans will tell you when something exciting is happening, and with luck which part of the crowd is baying will tell you roughly at which end of the pitch the excitement is happening in. But you’ll be oblivious to the match itself, to the intricacies of what the players and the ball whizzing between them have been doing for ninety minutes. To understand a match, we need to watch the players. To understand the brain, we need to watch the spikes.
That I can now tell you this story is thanks to the current golden age of neuroscience, where we find ourselves in the white heat of a technological arms race. A race to record as many spikes from as many neurons at the same time as possible. For after all, the reasoning goes, if spikes are what we need to understand the brain, then surely we need to capture as many as we can. A race to trace the wires of as many neurons as possible, to know where each neuron sends its spikes: to its neighbours, to its cousins in other regions of the brain, and to distant lands, the other side of the brain. And a race to precisely control those neurons, to turn spikes on and off at will, to know about causality: about what in the world causes spikes, and what they cause to happen in the world.
With all that, with the spikes, and the wiring, and the causality, we can finally know something about your life in spikes. And I can write a book telling you all about it.
The Spike: An Epic Journey Through the Brain in 2.1 Seconds is published by Princeton University Press, and available now from your favourite bookseller in hardback, e-book, and audiobook.
Read all about it, including a sample chapter. Listen to a sample from the audiobook
More praise for THE SPIKE:
“This book is truly wonderful. Mark Humphries takes us on a magical, demystifying tour of the brain, letting us tag along on a neural signal’s journey from eyeball to hand — as when you see a mosquito and swat it. Rollicking but deftly organized, The Spike is cast in everyday, easygoing language yet backed by tight science and state-of-the-art insights. This book’s fresh approach will charm novices as well as old neurobiological hands.” — Patricia S. Churchland, author of Conscience: The Origins of Moral Intuition
“The Spike is a fun yet deeply informative account of the electrical journey that information takes as it passes into our eyes and through our mind, and ultimately leads us to act. Drawing on the latest neuroscientific discoveries and theories, Humphries tells a compelling story of how minute changes in electrical signals in the brain give rise to our thoughts and actions.” — Russell A. Poldrack, author of Hard to Break: Why Our Brains Make Habits Stick
“The Spike gives a brilliant overview of our current understanding of brain function, from perception to action, based on our knowledge of systems neuroscience. Conveying ideas and concepts with impressive clarity, Humphries covers an astonishing amount of scientific literature. A joy to read.” — Matthias Hennig, University of Edinburgh
Want to know more about the brain? Follow us at The Spike on Medium
Twitter: @markdhumphries
