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Happiness in the Brain
Would you like to be stuffed into a tube? Head first?
Donât answer yet, because thereâs more.
Would you like to be stuffed head first into a tube, a cold and confining one, where youâre not allowed to move? For hours at a time? A tube that makes incredibly loud noises, an ongoing din of clicks and screeches like an enraged metal dolphin?
Pretty much everyone would say no if asked this question, before hurriedly seeking out the nearest authority figure. However, imagine not only agreeing to this, but actually volunteering for it. Repeatedly! What sort of person would do that?
Well, me. Yes, Iâve done this many times. And I would do it again if asked. I donât have a weird and incredibly specific fetish, but I am a neuroscientist, a keen student of the brain and a science enthusiast, so in the past Iâve volunteered for various neuroscience and psychology experiments. And since the dawn of the current millennium, many of these experiments involved having my brain probed by fMRI.
MRI stands for Magnetic Resonance Imaging, a complex hi-tech procedure which uses powerful magnetic fields, radio waves and several other types of tech-wizardry to produce very detailed images of the inside of a live human body, revealing things like broken bones, soft tissue tumours, liver lesions and alien parasites (probably).
But more attentive readers will have noticed that I referred to fMRI. The âfâ is important. It stands for âfunctionalâ, so itâs functional magnetic resonance imaging. This means that the same approach used to look at the structure of the body can be adapted to observe the activity of the working brain, allowing us to witness the interactions occurring between the countless neurons that make up our brains. It may not sound that impressive, but this activity is essentially the basis of our mind and consciousness, in much the same way that individual cells make up our body (cells combine in complex ways to form tissues, which combine in complex ways to form organs, which combine to form one functioning entity that is you). Scientifically speaking, this is a fairly big deal.
But . . . why am I telling you this? Weâre supposed to be looking at where happiness comes from, whatâs with the detailed description of advanced neuroimaging techniques? Well, while it would be dishonest of me to deny that talking about complex neuroimaging methods does indeed make me happy, there is a much simpler reason.
You want to know where happiness comes from? Well, what is happiness? Itâs a feeling, or an emotion, or a mood, or a mental state, or something like that. However you define it, it would be extremely hard to deny that itâs something that is produced, at the most fundamental level, by our brains. So there we go, happiness comes from the brain. Thatâs everything wrapped up in a page, right?
Wrong. While it is technically correct to say that happiness comes from the brain, it is also essentially a meaningless statement. Because, using that logic, everything comes from the brain. Everything we perceive, remember, think and imagine. Every facet of human life involves the brain to some degree. Despite massing just a few pounds, the human brain does a ridiculous amount of work and has hundreds of different parts doing thousands of different things on a second-by-second basis, providing us with the rich detailed existence we take for granted. So of course happiness comes from the brain. But thatâs like being asked where Southampton is and replying âthe solar systemâ; correct, but utterly unhelpful.
We need to know precisely where in the brain happiness comes from. Which part produces it, which region underpins it, which area recognises the occurrence of happiness-inducing events? For this, you have to look inside a happy brain, and see whatâs happening. Itâs no simple task, and to have any hope of doing it, you need sophisticated neuroimaging techniques, like fMRI.
See, told you it was relevant.
Unfortunately, there are several obstacles to this particular experiment.
Firstly, a decent MRI scanner weighs several tons, costs millions and produces a magnetic field powerful enough to pull an office chair across the room at lethal speeds. And even if I could get access to this super-machinery, I wouldnât know what to do with it. Iâve been in one many times, but that doesnât mean I know how to operate one, any more than taking a long-haul flight means Iâm a pilot.
My own neuroscientific research was into behavioural studies of memory formation.1 While this may sound impressively complicated and detailed, it mostly involved constructing elaborate (but cheap) mazes for lab animals to solve, and watching how they did it. All very interesting, but it means I wasnât trusted to operate anything more dangerous than a box cutter, and even then most people would leave the room, just in case. I was never allowed near anything as elaborate as an MRI scanner.
My luck was in, however. I live a very short distance from CUBRIC, the Cardiff University Brain Research Imaging Centre, where I volunteered for all those studies. It was being built as I completed my PhD at the Cardiff Psychology School, and was opened just after I left. This timing seemed a bit mean-spirited if Iâm honest, like the whole institution had said, âIs he gone? Good, now we can break out the good stuff.â
CUBRIC is an excellent place to go for the latest cutting-edge investigations into the workings of the human brain. And, doubly lucky for me, I have friends who work there. One of these friends is Professor Chris Chambers, prominent expert and researcher in brain imaging techniques. He was happy to meet with me, to discuss how I planned to go about locating happiness in the brain.
However, this would be a business meeting, not a social one. If I wanted to convince a professor to let me use his incredibly valuable equipment to pursue my personal investigation into how the brain processes happiness, I needed to make sure Iâd done my homework. So, what does science already know, or suspect, about how happiness works in the brain?
Chemical happiness
If you want to know which bit of the brain is responsible for happiness, consider what counts as a âbitâ of the brain. Although itâs often thought of as a single (surprisingly ugly) object, it can be broken down into a vast number of individual components. The brain has two hemispheres (left and right), made up of four distinct lobes (frontal, parietal, occipital, temporal), each of which is composed of numerous different regions and nuclei. These are made up of brain cells called neurons and numerous other vital support cells called glia, which keep things functioning. Each cell is essentially a complicated arrangement of chemicals. So you could say that, like most organs and living objects, the brain is a big lump of chemicals. Chemicals arranged in breathtakingly complex forms, but chemicals nonetheless.
In fairness, we could break it down even further. Chemicals are made of atoms, which are in turn made of electrons, protons and neutrons, which are in turn made of gluons, and so on. You end up getting into complex particle physics as you delve deeper into the fundamental makeup of matter itself. However, there are certain chemicals the brain uses for purposes beyond basic physical structure, meaning they have a more âdynamicâ role to play than just being the building blocks of cells. These chemicals are neurotransmitters, and they play key roles in the functioning of the brain. If youâre looking for the most simple, fundamental elements of the brain that still have profound impacts on how we think and feel, these chemical neurotransmitters would be them.
The brain is essentially a huge and incredibly complicated mass of neurons, and everything the brain does is dependent on, and the result of, patterns of activity generated in these neurons. A single electrochemical signal, a pulse known as an âaction potentialâ, travels along a neuron and, when it reaches the end, is transferred to the next one in line, until it reaches where itâs meant to go. Think of it like an amp travelling along a circuit from a power station to your bedside lamp. Itâs quite an impressive distance for something so insubstantial to travel, but itâs so common we barely even consider it.
The pattern and rate of these signals, these action potentials, can vary enormously, and the chains of neurons relaying them can be incredibly long and branch off almost endlessly, allowing for billions of patterns, trillions of possible calculations, supported by connections between almost every dedicated region of the human brain. Thatâs what makes the brain as powerful as it is.
Stepping back slightly, the point at which the signal is transferred from one neuron to the next is incredibly important. This occurs at synapses, the point where two neurons meet. However, and hereâs where it gets slightly strange, thereâs no significant physical contact between the two neurons; the synapse itself is the gap between them, not a solid object. So how does a signal travel from one neuron to the other if they donât touch?
Neurotransmitters is how. The signal arrives at the terminus of the first neuron in the chain, and this causes the neuron to squirt neurotransmitters into the synapse. They then interact with dedicated receptors in the second neuron, and this causes the signal to be induced again in that neuron, and itâs then relayed along to the next one in line. And on it goes.
Think of it like an important message, sent by the scouts of a medieval army to the commanders back at headquarters. The message is on a piece of paper, being carried on foot by a soldier. He reaches a river, but needs to get the message to the camp on the other side. So, he ties it to an arrow and fires it across, where another soldier can pick it up and carry it further along the journey back to headquarters. Neurotransmitters are like that arrow.
The brain uses a wide variety of neurotransmitters, and the specific neurotransmitter used has a palpable effect on the activity and behaviour of the next neuron. Thatâs assuming the next neuron has the relevant receptors embedded in its membrane; neurotransmitters only work if they can find a compatible receptor to interact with, a bit like a key only working for a specific lock, or series of locks. To go back to the soldier metaphor, the message is encrypted so only those from the same army will be able to read it.
Thereâs also a wide variety of orders the message could contain: attack, retreat, rally forces, defend the left flanks, and so forth. Neurotransmitters are similarly flexible. Some transmitters increase signal strength, some reduce it, some stop it, some cause different responses altogether. These are cells weâre talking about, not inert electrical cables; theyâre diverse in how they react.
Because of the diversity offered by this setup, the brain often uses specific neurotransmitters in certain areas to fulfil certain roles and functions. So, with this in mind, is it possible that there is a neurotransmitter, a chemical, responsible for producing happiness? Surprising as it may seem, this isnât that far-fetched. There are even several candidates for such a thing.
Dopamine is an obvious one. Dopamine is a neurotransmitter that fulfils a wide variety of functions in the brain, but one of the most familiar and established is its role in reward and pleasure.2 Dopamine is the neurotransmitter underpinning all activity in the mesolimbic reward pathway in the brain, sometimes called the dopaminergic reward pathway in acknowledgement of this. Whenever the brain recognises that youâve done something it approves of (drunk water while thirsty, escaped a perilous situation, been sexually intimate with a partner, etc.), it typically rewards this behaviour by causing you to experience brief but often intense pleasure triggered by the release of dopamine. And pleasure makes you happy, right? The dopaminergic reward pathway is the brain region responsible for this process.
Thereâs also evidence to suggest that dopamine release is affected by how surprising a reward or experience is. The more unexpected something is, the more we enjoy it, and this seems due to how much dopamine the brain deploys.3 Expected rewards correspond with an initial dopamine surge, which then tails off. But unexpected rewards correspond with an increased level of dopamine release for a longer period after the reward is experienced.4
To put this in a real-world context, if you see that money has arrived in your account on payday, thatâs an anticipated reward. Conversely, finding ÂŁ20 in an old pair of trousers, thatâs unexpected. The latter is much less money, but itâs more rewarding, because it wasnât expected. And this, as far as we can see, causes a greater dopamine release.5
Similarly, absence of an expected reward (e.g. your pay isnât in your bank account on payday) seems to cause a substantial drop in dopamine. Such things are unpleasant and stressful. So, obviously, dopamine is integral to our ability to enjoy things.
But as mentioned previously, supporting pleasure and reward is just one of dopamineâs many and varied roles and functions across the brain. Perhaps other chemicals have more specific roles in inducing pleasure?
Of course, endorphin neurotransmitters are the âbig daddyâ of pleasure-causing chemicals. Whether they are released from gorging on chocolate or due to the rush of sex, endorphins provide that oh-so-wonderful intense giddy warm sensation that permeates your very being.6
The potency of endorphins should not be underestimated. Powerful opiate drugs like heroin and morphine work because they trigger the endorphin receptors in our brains and bodies.7 Theyâre obviously pleasurable (hence the alarming number of people who use them), but these drugs are also clearly debilitating. Someone in the grip of an intense opiate âhighâ isnât much good for anything other than staring into space and occasionally drooling. And some estimates suggest that heroin is only 20 per cent as potent as natural endorphins! We have substances five times as powerful as the most intoxicating narcotic just hanging around in our brains â itâs a wonder we get anything done at all.
While itâs bad news for pleasure seekers, itâs good news for the functioning of the human race to hear that the brain uses endorphins very carefully. Most typically, the brain releases endorphins in response to serious pain and stress. A good example of both is childbirth.
Mothers use many terms to describe childbirth â âmiraculousâ, âincredibleâ, âamazingâ, and so on â but âenjoyableâ is rarely among them. And yet despite the extreme physical demands it places on a womanâs body, they get through it, and often do it again. This is because human women have evolved many different adaptations to facilitate childbirth, and one of these is the build-up and release of endorphins as it progresses.
The brain deploys endorphins to dampen the pain and stop it from ...
