Many people who study the brain (or just want to read about it in their spare time) assume they have to understand….. the brain. As in the whole brain. But with 100 billion neurons and 10,000 connections between each one firing 10 times a second, that’s really a bit much to expect of yourself. In the end most of us focus in on just one level of the brain’s hierarchical organization – the gene level, or the cell level, or the region level, or the circuit level – and essentially leave thinking about the rest of the brain to someone else.
For most psychologists, the level at which they intuitively attempt to understand the brain is at the whole-brain level. As an analogy, if the brain were the United States, and the psychologist were a bird, she would be flying at around 36,000 feet on a clear day – roughly the height of a jet plane crossing the country. From that height you can see whole brain regions the way a plane can see whole states. “Hey! There’s the dorsolateral prefrontal cortex – I mean California – that’s where American culture makes its decisions. Hey! There’s the amygdala – I mean Louisiana – that’s where Americans feel constantly in danger. Hey! There’s the motor cortex – I mean Texas – that’s where American culture is obsessed with physical prowess.”
From way up there the psychologist can notice big picture concepts, described in the sorts of words that drive everyday folk-psychological talk about the mind. But a funny thing happens to this psychologist when she acts like a real bird and….. flies down to earth to find somethign to eat. And a place to sleep. And sit on her eggs. Like all birds, she must come to rest in a particular place, from which concepts like states and countries and cultures don’t quite make sense. Perhaps she lands in Manhattan, on the upper west side, at 525 W. 120th street, on the third floor, outside a window, and sees me talking to a group of students. The neural equivalent would be that she has dropped down from looking at the whole brain to a region to a gyrus to a circuit to a single neuron. I’m the neuron.
The question is: will she know what she is looking at? Can a bird who “understands” all of America also understand me? And if not, then does she really understand the whole country?
There is nothing in any neuroscientist’s, any medical student’s, any psychiatry resident’s, any psychologist’s training that has prepared them to think about the psychology of an individual neuron. To someone used to thinking about the psychological function of the prefrontal cortex, with its 30 billiion neurons, asking them about the psychology of one neuron is like asking Freud what he meant by the letter “t”, which, clever you, you’ve noticed appears in over 15% of all of his words! It seems like a crazy, nonsensical question. But is it? Neurons don’t do anything that resembles normal human psychology – do they? Only whole regions create human psychology, right?
In a word, no. And in three words, no, no, no. Unless you don’t believe in cultural differences – which is like saying you don’t believe the brain has different parts, or that psychology doesn’t have different faculties, or that any two given populations of anything in this world won’t have different means
– you know that cultural differences are, in the end, manifested as individual differences. (In fact, that’s how social scientists see cultural differences in the first place – they observe and interview large numbers of interacting individuals).
You can probably see where this argument is going by now. If sociology is interested in how individuals think and interact, and psychology is interested in how individuals think and interact, and if the key to understanding the whole world is to be able to understand individuals, then isn’t the individual neuron the most fundamental unit of psychology?
The answer in this chapter is yes. By spending significant time looking at neurons from a new perspective – not from our egocentric perspective, but their neurocentric perspective – we will see two very cool things. First, individual neurons have a psychology. They have goals, they make mistakes, they try to correct them. And second, the psychology of an individual neuron can be ‘scaled up’ and used to understand the psychology of the whole brain. New principles are added as we ascend the ladder, but these ones, like all foundational principles, always apply.
For readers who suffer from neurophobia, there is no way around it. You are actually going to have to think about neurons. And you are actually going to have to think about all the things that make a neuron a neuron – its proteins, its cell membrane, its synapse, its electric field. But luckily, the entire point of this book is that thinking about these as structures is the wrong way to think about them. And so I am hardly going to talk about them as though they were physical objects. Rather, I am going to talk about them as though they were what they are – psychological ideas. This is going to be a warm-up to the next chapter, where we introduce the concept of visvox.
However as weith everything else in life, you are going to have to do some prep work before these ideas can really seem as cool as they are. You are going to have to pretend you are five again, and at the pet store, and you are going to have to pick a neuron out of the tank, and put him in a plastic bag, and take him home, and stick him in a bowl by your bed, and treat him like a pet goldfish. You are going to have to become very comfortable with him. He’s yours. Name him. (Mine is called Nunu.) It’s going to be like that.
You are going to get to know your neuron very well: his feeding habits, what makes him excited, what calms him down, what makes him sick, and so on. You are going to know him like a pet. To help you understand him I am going to make sure you see him as having a personality, and by the end of the chapter you may find him so cute that you start drawing pictures of him and writing his name and thinking about him all the time. Which is great.
Because just as childhood crushes are the forerunners to adult love, and begin to teach you the basics of how to like someone and (hopefully) get them to like you back, your crush on your neuron will become the foundation for a love affair I want you to have for the rest of your life, with your brain.
The good news, for you neurophobics, is that I am not throwing you into the whole brain. I am not giving you any fancy names to memorize. (It took me years to understand what the heck was supposed to go through my head when my favorite teacher said “dorsolateral prefrontacl convexity,” which he said a lot. I felt very stupid.) I am just giving you one neuron, and for the rest of your life, just by thinking about him, you will be able to derive almost everything you could ever want to know about how the neuroself works. And here’s the really cool news: you’ll be way, way ahead of most professional neuroscientists, most of whom can’t think straight about neurons, and therefore can’t go “all the way” when they try to think about the brain.
The bad news (you thought you’d already gotten it, right?) is that before you are ready for your goldfish – I mean your neuron – there are some basic concepts you need to master to avoid disaster. Just like your mom made sure your five year old self understood that goldfish need food and clean water and room to swim and maybe a friend before you actually brought home (and accidentally killed) your pet, I need to make sure you understand three things before you bring home your neuron. Otherwise the wonderful idea he will grow into will be D.O.A. They are the equivalent of food, water, and friendship, and are what neurons, like goldfish, need most. Oh, and one more thing, that both neurons and goldfish need. A sense of purpose.