Can chocolate make you happy?

20 June 2014
Presented by Hannah Critchlow.

Beat anxiety, form healthy habits and induce a happy state of mind. We open our minds by tackling your questions about the brain.

In this episode

00:00 - Why are mental health problems so common?

Why are mental health problems so common?

Hannah - Hello. I'm Hannah Critchlow and this month in Naked Neuroscience, we'll be opening our minds with a special Q&A show. We'll be discussing treatments for depression.

Liz - So the first in my life, I took antidepressants. It felt like I've been a car that had something wrong with the engine and then it's kind of dragging along the road and someone had fixed it. It was just rolling really beautifully.

Hannah - Discovering how we can change our behaviour for the better.

Roger - So we said a little while ago, I said, "A new habit takes about 82 days to form." So actually, we can be patient with ourselves as things get going. It's not instant.

Hannah - And divulging tricks to help you lose those extra pounds.

Katie - You sit in front of the tele and eat food, you don't realise quite how much you're eating. You don't attend to it and you don't feel fill so quickly.

Hannah - We've had stacks of great questions in from you and accrued of brainy panel to tackle them. They are.

Roger - I'm Dr. Roger Kingerlee. I work in Norfolk and Suffolk NHS Trust as a clinical psychologist with a particular research interest in mild psychological health.

Liz - My name is Liz Fraser. I'm an author and broadcaster and I have recently setup the website inmyheadcase.com to completely change the face of mental health.

Martin - Martin O'Neill and I use basic neuroscience techniques to investigate decision making mechanisms.

Katie - I'm Katie Manning and I'm a PhD student here at Cambridge in the department of psychiatry and I use MRI imaging to look at connectivity in the brain.

Hannah - And with them, we'll be finding out why chocolate helps to boost happiness. We'll be stumping scientists with the question, is there such a thing as freewill or is life all predetermined? And have you ever heard or seen things that other people don't, so experienced hallucination? Apparently, 10% of the population do. And we'll be discussing the case of a musician who hears music when he's nodding off to sleep.

First up though, David Bailey got in touch asking, "Why are brain conditions and mental health problems so common?"

In children, there's been a 25-fold increase in autism diagnosis over the last 20 years. Now, 1 in every 100 of primary school children will be affected in the UK whilst 1 in every 20 school children will have a diagnosis of attention deficit hyperactivity disorder or ADHD and it's not only children. Overall, the percentage of adults diagnosed with mental ill health has steadily increased. The best estimates today suggests that 1 in 4 people in the UK will experience a problem every year with 10% of the population affected by, for example, depression or anxiety. So, is it just that we were better at recognising conditions and seeking help, or something about today's society be to blame? First up, Roger.

Roger - Well we know from the statistics you've already mentioned that all of our families and all of our workplaces, we can have people around us who have these issues if we haven't got them ourselves. If we go back evolutionarily, one of the things we know is that life is always very challenging and potentially very stressful. So, right from the world ago, we've always faced a lot of different threats in the environment. The threats can produce stress in all sorts of different ways. We know that stress is a big driver of psychological issues of all kinds. To come back to the present of course, especially since the recession, since around 2007, 2008, most people, most families at least in the UK often work harder.

Hannah - Is there anything that we can do to try and help protect ourselves against this increasing mental health problem?

Roger - There's a huge amount we can do. So, whether that's giving ourselves a little more time to look after ourselves, whether it's doing things like using relaxation techniques or increase the meditation techniques, so much is known about how to protect ourselves.

Liz - It is fairly destigmatised now. I think people are not frightened anymore. They still are, but less so to put their hand up and say, "I'm not dealing with things very well. I'm not coping very well." We have to be so careful when we talk about increase in the numbers of cases of things. Is it just because we're reporting it more? Why would we be reporting it more? Because the knowledge is out there so we know much more about it. Therefore, we're reporting it more. Therefore, there is more diagnosis and therefore, there is more prescriptions. I don't agree with that. I think that the evidence seems to suggest that they are in fact increasing and what you were talking earlier about stress. And it's funny because people often say, "Well, you know, life is easy. We're not at war." There aren't the sort of the daily manual struggles that people used to have. But actually, one of the things that we know causes a lot of - I suppose stress and unhappiness in people is a difference between expectation and reality. And so, I think so many people now are not living the normal life path that they perhaps expected to live. That sort of very traditional, 'grow-up, get a job, get married, have a house' with is maybe not crazy, but at least it has a stability and because that's perhaps boring but at least stable framework. This doesn't exist for so many people. The levels of stress are really on the increase and as you're quite right, you said, stress then causes all of these problems.

Roger - Just to point out, it's well-known that social support can be really important, is a buffer against stress and psychological issues. Perhaps even against physical issues as well. So, that's something else we can do - actively seek out support.

Katie - Although there's still a stigma that surrounds mental health, there's now more options and availability of support particularly with things like autism when a child can be diagnosed and that diagnosis opens up the availability of various forms of support whether that be in education or outside of education. That now, getting that diagnosis is actually important in terms of getting help for somebody's child whereas in the past, if that was just destigmatising diagnosis then that was perhaps something to shy away from.

Martin - Thinking from a basic neuroscience perspective as well, we've come to appreciate just how intricately designed the brain is with billions of neurons, billions of connections between neurons, billions of chemicals. So, it's actually perhaps not that surprising. When there's a little glitch in the system, there can be these profound effects on mental processes, emotional processes. In effect, that sort of appreciation helps is the destigmatisation as well and it's what's almost making mental disorder seem like they're becoming more common. But perhaps have always been around but we are just more willing to accept and address those issues.

Hannah - There's another area of neuroscience that's really kind of gaining a lot of information, and also momentum. That's the neuroscience of resilience - so how we can become more resilient to these stressors and how we can maintain a flourishing and happy mind in society as well.

07:08 - Can chocolate make you happy?

Can chocolate make you happy?

Next question, I think this leads on rather nicely. Does chocolate have an anti-depressant effect? In my experience, eating half a bar or even sometimes an entire bar of chocolate can make me feel much happier. Are there any neurochemical basis for that?

Martin - Yeah. I mean, chocolate raises blood sugar levels quite dramatically and quickly. That increases glucose delivery to the brain which is basically fuel to the brain among other nutrients. So, if you give the brain a short shot boost of one of its essential fuels and you can enhance the brain's happiness I guess.

Katie - We often hear reports of all sorts of wonderful qualities of chocolate which we all love to be absolutely true. Actually, there's a review that was done by (Hocker)(7:52) and colleagues that was just looking across what might be the anti-depressant effects of chocolate. There are some small levels of psychoactive substances in chocolate but it's in much smaller quantities and you find in lots of other foods.

Hannah - By psychoactive substances, are you talking like there's miniature traces of LSD type compounds in chocolate?

Katie - No. So, we're talking sort of stimulants like caffeine sort of stimulants in very, very small amounts.

Liz - I was really interested in how much of that is because we've been told that chocolate is good. It makes you feel good and the adverts are great and there are half-naked ladies and they're eating chocolate and how wonderful they feel. How much of that has gone into our minds if we've been told that carrots are, "My God! Carrots are only the best things ever!" How much is a feedback loop of what we've been told that chocolate is wonderful? But we have to remember that chocolate, it goes back thousands of years. And so, there were people in the jungle at one point who ate coco beans and for the reasons, it does do something chemically to you. But the chocolate that we eat, it's basically sugar. A little bit of coco, but the rest is sugar and blah, blah, so a huge effect must be to do with that.

Hannah - I had a quick search and there's a paper published in the journal of Chromatography A by Pollo Diaz and colleagues last year and they found that they did some clever chromatography mass spectrometry of a chocolate and they found that the highest serotonin content - so that's like a happy chemical in the brain - was found in chocolate with a coco mass content of over 85%. As well as one thing that serotonin, dopamine release in our brain, we also enjoy a fat and of the high milk content, and also the sugar burst.

Liz - Because actually, if you eat 85% chocolate, it's pretty unpalatable. It's really bitter and I quite like it, but there's a percentage beyond which most people really don't enjoy it at all and exactly said that there's a perfect ratio which I'm sure, all chocolate manufacturers spend all day trying to find which is the one that just ticks all the boxes. But I think advertising has a lot to work for here.

Martin - I think it's also the rapid metabolism, the rapid release as well because let's not forget, they've got complex carbohydrates like sugar is present. The healthier foods for example bananas are a high source of tryptophan which is a precursor for serotonin. But it takes a lot longer for the body to breakdown these chemicals and process them and deliver them to the system whereas with chocolate and coco has a sharp boost which also I think could result in the crash. It's like a post glucose crash.

Katie - Because actually that high sugar and the high fat content as well that you find in a lot of other foods that people eat that give you - you know, donuts and cakes and gives you that short shot boost.

10:31 - How best to treat depression?

How best to treat depression?

Hannah - Thank you and next question now, Michael Malone has been in touch saying, "People seem to want treatment for depression, but most are afraid of the side effects of the medications. What are your thoughts on this?" And he says thank you.

Roger - Depression is a huge issue. It's important that when we have the feelings or the symptoms that we do get help because there are various treatments, both medical and psychological that can be really helpful. So, it's great to actually go and get help in the first place. As a psychologist, I'm not qualified to talk about the medications per se, but what I would say is, if there are any kind of doubts there at all, the first thing to do is to go to someone's GP, speak to a pharmacist rightfully off or a psychiatrist if available, and get really good information right from the start because it's very common that all different individual people are so genetically, different medications affect people in different ways and there can be interactions and stuff between the medications. It's really important to get good quality advice really right from the start and that can really be helpful. That's the medication side of it. Also, as a psychologist, I have to say that we know very many psychological methods. There's a very good evidence base that help for depression with many psyches or psychological therapy whether it's CBT, cognitive behavioural therapy, psychodynamic ways of working. It's probably more likely than not that we're going to get some symptom reduction if we engage well in those therapies. So, there's an awful lot that can be done is the message.

Liz - I think one of the most difficult things is just drawing that line between how much can you cope with, can you manage without medication and using alternative therapies. I think many people find it very difficult to know at what point can I not manage this anymore on my own. At what point should I go and get some sort of chemical treatment at the end of the day? Of course, the most difficult thing with a lot of the drugs that will then be given to you is that many of their side effects are very similar to the original problem that you were having. So, some treatments for anti-depression can actually cause anxiety. They can cause paranoia. They can cause more feelings of depression. So, the last thing you want to do is to take something which makes that even worse. If you look at the history of medicine or the history of diagnosis and treatment, it tends to go through quite long waves, but it does go through waves and perhaps we've just come through 50 years of chemical intervention or treatment which we've been learning as we go along - what works, what doesn't. We don't tend to electrocute people anymore and do that kind of thing and now, it's this. Maybe we will now perhaps come to a time where we're all going, okay, if the prescriptions of anti-depressants have gone up that much, have we now reach the point where are going to say this is ridiculous actually. As more people are learning about mindfulness and learning about yoga and learning about all these stuff which was seen as very hippy, trippy, and weird, and is now becoming so mainstream. If we really can show that that can cause a real benefit to you without having to take some chemical treatment then maybe we're going to come into a new time and a new way of treatment. But if you need the medication, I mean, really need the medication, I think people have to be very, very careful to understand when you do, you do because some things we can't just deal with on our own.

Hannah - Martin, Katie, there has been kind of this big wave that neuroscience and psychiatry can be cured by chemistry and but there's all these receptors all over the brain and actually, all over the body. So, if you're going to be treating a particular condition with a chemical like an anti-depressant for example then it will have side effects in other areas of the brain. Do you think that we're learning more now about discreet circuits in the brain so that we can start targeting particular conditions in a much more focused way without these side effects that people would really do worry about or is the answer, yoga or mediation. We're going to learn about the neuroscience of yoga and meditation in the future.

Martin - I think a lot of the early pharmaceutical treatments for mental health disorders were almost sort of magic bullet treatments maybe that we don't really know what Prozac and fluoxetine were really doing when internationally has been used widely. But we've got much better understanding of how these drugs are acting now and new drugs are constantly being developed to target more specific receptor subtypes dopamine as neurotransmitter in the brain which is involved in depression and anxiety, about serotonin and nor-adrenalin. But this don't just act upon one receptor type. They multiple receptor subtypes they act upon. We're getting more information and the key thing, what receptor subtypes may be more effective to target to treat more specifically anxiety, if they're having a side effect on sleeping for example, insomnia. These treatments are getting more focused with an increasing knowledge of basic neuroscience.

Liz - Can I just do a little personal sort of anecdote in here? I remember about 14 years ago after my second child was born, I went into a very big postnatal depression after that. I put up with it for a while and I saw a lot symptoms coming back that I recognised from 10 years previously and I thought I just don't want to go there again. So, for the first time in my life, I took anti-depressants and I have a diary of the time. I felt absolutely wonderful. I felt wonderful for about 6 months while I was taking it and I remember thinking, do other people live like this because this is fantastic. I can do everything. I can go shopping and I can deal with this and I'm pretty happy. I'm lovely to be around. It felt like I've been a car that had something wrong with the engine which is something wrong and it's kind of dragging around the road and someone had fixed it. It was just rolling really beautifully. I stayed on it for a year because they said a minimum of a year and that was 15, 14 years ago and have never done it since, but I think that if people really feel that they are really trying hard and it's not working, not to feel bad for seeking some kind of medical or chemical intervention because just to have that relief, it's like going on holiday for a while. It makes everything so much easier and then you can start to deal with the problems that caused it while being in a much stronger place.

Hannah - But then what happened after that year of taking this medication?

Liz - Well, I came off it rather more quickly than I perhaps should have because I wanted to have the child. Okay, I'm going to cleanse the system. You are supposed to come off very slowly. What happened? Well, I suppose what happened was that I haven't really needed it since then. One of the nice things I think is that I know that it's there. I know it's there and for me, it worked. I would always rather not take it. I don't like to take anything. If I had a headache, I will never take paracetamol. I just don't like taking stuff generally. So, that was quite a big step for me to take something. I think it's important to know when you need that. Take it if it works for you. Well, why not? If I have a sore knee, I will bandage it up to make walking easier. If I cut myself, I will put some antiseptic on a plaster on it. But I think we should see these things a little bit in that context.

Roger - And just to support you in that is when we first accept where we are releases us to move forward. It's when we are caught up in ourselves and we're kind of feeling bad and that's most difficult to get anywhere. Conversely, if we accept actually what's going on, we can begin to take the steps out.

Martin - Yeah, but also, we're understanding more about how things like oxygen and glucose do affect neurons in the brain. There are alternative treatments and I think things like doing breathing exercises can be very efficient, as it relates to a point earlier on about having chocolate and getting glucose into the brain. This is also why exercise is recommended as a good way to try and deal with depression and anxiety because actually, you're boosting delivery of a natural fuel to the brain - oxygen.

18:06 - What does exercise do to the brain?

What does exercise do to the brain?

Hannah - And that links in really neatly with the question that Sherburne de Garmo has been in touch with saying, "What effect does exercise have on the brain?"

Martin - I can talk I think reasonably about what the effect of exercise on mood because I very often say to people, if you're feeling low or feeling anxious, feeling kind of under stress, get some exercise because we know it has profound and evidence based of effects on mood. Whether it's walking or cycling, I think that's one of the profoundly hopeful points out of all this, that actually, the brain probably is not a fix structure. Moods aren't fixed. They're fluid and it's very hopeful because we can do a lot ourselves to change them in a positive direction.

Hannah - What effect exactly does exercise have on the brain? So, Martin mentioned increased oxygen to the brain and that can obviously be quite helpful to keep those nerve cells functioning optimally. But what other effects can exercise have?

Katie - We often think of exercise as just to keep fit and keep the rest of the body healthy, but it does have quite have big effects in the brain. It's been implicated in what we call neurogenesis and that's the ability to actually grow new neurons inside the brain, in the hippocampus, which is heavily, heavily implicated in learning and memory. There are some experiments on mice by Professor Rusty Gage and he looked at mice in cages with running wheels and without. The mice that had access to these running wheels actually grew lots of new cells in the hippocampus and this finding has been extended to humans. So, a lot of neuroscientists will now jog. In terms of mood, actually there's evidence that exercise can help speed up recovery from depression and it's associated with a good mental health as people age. To some extent there's some evidence that it can increase the availability of serotonin and nor-adrenalin so chemicals in the brain that are implicated in mood. As a lot of people know then that exercise stimulates the endorphin release. These are chemicals and when they're released, they bind to receptors in the brain and the subreceptors that they bind to revolved in pain signalling and they actually disrupt pain signals that you get. And so, they would reduce some of the feelings of pain that many of us get when we exercise hard. Whether that's actually about the 'feel good' that you get from exercise or whether that's it, it takes a weight in the pain and you even can then benefit from the stimulation of some of the other chemicals like the serotonin in the brain isn't quite clear.

Hannah - Exercise can flood your brain with feel-good factors and increase the number of brain cells that you have and help with your learning memory. And also, I found a paper where stress exposure which causes lots of release of this stress hormone cortisol, you can become resilient to that via exercise because exercise will increase this brain derived neurotropic factor, BDNF which helps protect against the cortisol stress effect or at least in mice any way. It increases your resilience, that's nice. But what about the fact that if you're feeling low, if I'm feeling low, the last thing that I feel motivated to go and do is go out for a jog and I love jogging most of the time. So, how can you motivate yourself to go out and get this brain-boosting kind of positive effects of exercise?

Liz - Basically catch-22 and it is exactly that. You know, when you're in that place, you can't move. You just can't get out of the room, you can't get off the chair, let alone, go for a jog. Unfortunately, that really does come down to the individual person. I mean, beyond having an app that bleeps at you or a phone that's going to ring or a friend that's going to bang on the door and say, "Come for a run", actually, at the end of the day, you have to get off the chair and I always say to people, just walk around the block. Walk down the road and back because once you've got out of the house. So many mental health problems actually are just to do with sort of cycles of thought. Once you're going in this cycle of thought, all you need to do is pivot. You just need to pivot that train of thought which is going around and round, and pick on to another. It can be the tiniest thing - listen to a piece of music, watch some comedy, call a friend, anything, and you can almost feel it when that changes. I feel my eyes change, my whole mood changes because suddenly, I'm not going down that really bleak thing. And so, the exercise thing is really a part of that, just the very fact that you're doing that means that you're no longer going down one part. You're going down another. And you have to be the one to do that unfortunately.

Roger - Just to back you up in that, there's this evidence going back a few decades now for a type of a kind of CBT cognitive behavioural observation. So actually, getting things going, different behaviours, being more active, you know, particularly exercise, that helps us to - is known to be very good for mood. The clinical mantra is on a day-to-day really is even if you don't feel like it, do it anyway because as you were saying, if you do it, 10 minutes or 15 minutes in, you'll get the benefits.

Martin - As been suggested, there can be quite a futile gesture to tell somebody who's really in the depth of depression for example to go out for a jog or to start eating healthily. But you know, I think we can really sort of think about these things like other sort of physical attributes as well. So, if you're overweight, you can't do it for one jog and drop 4 inches off your waistline. But you can prevent becoming overweight by exercising regularly. I think that gets to this combination of using maybe pharmacological treatments to bring somebody out that they have some depression. But then educating people on how stay out of that state, how to avoid going into that state again, and that's where things like getting healthy and exercise I think are very useful.

Liz - That's one of the things which can make depression worse. You know why? Because not what you just said, but the idea of knowing what you know what you have to do. This is why I keep saying to people over and over again, do you know? Actually, nobody ever needs to read it on the magazine or be told all of this stuff. We know this and so, it's the fact that you kind of sit there going, "Look, I know what I have to do, but I feel that I don't have the strength within me to do that" and that brings us back to the question about medication and intervention. If that's the crutch that you need in order to stand up, take that crutch, but you still need to walk and no one's going to make you do that apart from you.

Roger - And just to go back to the point back because it's all about clinical change, psychological change is that actually, it's okay for that to happen in small steps to get in by just going slowly. And there was some research a little while ago that said a new habit takes about 82 days to form. So actually, we can be patient with ourselves as things get going. It's not instant. We can work until that's okay too.

24:20 - What to do if you feel anxious everyday?

What to do if you feel anxious everyday?

Hannah - And Jonathan Michael has been in touch saying, "If you are always feeling anxious every day, is it considered an anxiety disorder? Should I go to the doctor when it happens to me?"

Roger - Most people probably are at least a little bit anxious every day. So, we'll often get feelings of anxiety doing various things. First of all, anxiety itself is complex. There are various different issues, so they might be social anxiety, it might be a kind of panic-based problem, it could be a generalised anxiety disorder, GAD. It could be tied up with other things for example like post-traumatic stress. Anxiety is complex. Psychologically, one of the things that we want to look out for is when the worries are really chronic, if the anxiety is interfering markedly with our day to day functioning, and/or we're worried about it then it's a good idea to get some help. It's now a good idea to get some help because it's so much psychologically that we can do to reduce anxiety.

Hannah - I mean, it's quite natural response, anxiety as well, isn't it? It's something that we are and have evolved to experience as part of the fight or flight response. So, we've evolved to either fight something or someone that we're scared of - a predator in the environment or to run away. I remember when I first started this job, I was incredibly anxious when I had a particular interview. The main producer of the show, Ben said, "What you want to do is go for a quick walk around the block. That might make you feel better." That's kind of the flight response. And so, I came back in. I was like, "I feel a bit better, but not that much better." He went, "Okay, have a hug." And that seem to help it a bit.

Liz - I think anxiety is one of those ones. We know with psychological things, you can't even measure it. I mean, how much is - on a scale of 1 to 10, how anxious are you feeling? 1 or 4, maybe 7. I have no idea. A leg is broken or is not broken, we can measure this. Psychological things are so much more difficult. As you were saying, it's the point at which you can't go back your everyday life in a normal way that you can't function a normal way. That's the point where it's reached a problem if you like, if you can't function normally, but yeah, a bit of anxiety is completely normal and as you say, really very useful in certain circumstances.

Hannah - Yeah, help me prep for the interview in that particular instance. I got a burst of adrenalin which I think helped. But had that prolonged, given that had been every single day then I think I would've had to have gone and sought some help.

Katie - Yeah, I mean, if it is a problematic thing to somebody, it isn't interfering with their lives, I think it's also important to remember that they're not alone. Anxiety is one of the most common mental health problems in the UK. You shouldn't feel that you have to struggle with it alone. Go and see your GP. They'll be able to talk to you. They'll be able to diagnose you with an anxiety disorder if that's the right thing to do or help you find other ways in which you can address any issues you're facing or ways to actually help you feel better and control that anxiety. So, I think if you have ever at all worried about the way you've been feeling or the anxieties become really unpleasant and frequent then just go and see a GP. They'll be able to offer advices specific to your needs in your circumstances.

Martin - From those comments that have just been made, it's sort of occurring to me that it seems that like, it's difficult to measure psychological disorder like anxiety and to be able to appreciate when it becomes a clinical disorder than just normal state of being, a normal feeling of anxiety. Although we can't measure as clearly as physical pain, maybe it's a good idea to sort of think about it, an analogy to physical pain. So, if you had back pain for example, if you had some sort of niggling in your back, most people would maybe let that stay after a day or two whatever, but if that continued and started to impact on your daily routines, there will be a point where you think, "Okay, I want to make an appointment and go and see the doctor." So maybe if people could think of it that way, if this is actually having an effect and it's detrimental to your daily routine, just think, "If this was my back or my knee, would I make an appointment?" And so, yeah, seek out.

Roger - There are many, many things that we can do actually with anxiety to change things around quite quickly - some of them like exercise, some of them like relaxation. Sometimes you can get results within a few minutes. People can feel the difference, feel the heart rate going down, feel the physiological benefits of what we're doing differently.

Liz - The reason I set up my case was because when I had all the anxiety issues that I had, I found that when I started to talk about it with people, almost every single person I ever spoke to either said, "Oh, I had that too or my friend or my husband, or my child had that." And I thought, "Hang on, this is endemic." And yet, when I asked them, "Well, have you talked to anyone about it?" They will always say, no. "No, I never talk about it." And so, oddly enough, anxiety is the most common mental health disorder that we have in our society now. Still, nobody is talking about it, which is extraordinary. But that's going to change. I mean, I really think that's going to change. Most people hadn't heard about anxiety disorder even 5 years ago particularly whereas now, it's a little bit like a bipolar disorder which again no one had really heard about. A little while ago, now everybody kind of understands something or what it might be. I think that's great if we can open that box and let people talk about it and then get help for it.

Hannah - Thank you for that Katie Manning and before that, Liz Fraser, Dr. Roger Kingerlee and Dr. Martin O'Neill. And we'll be returning to our brainy panel later in the show to find out how much of our brain we have conscious control over. We'll be asking, is there such a thing as free will and finding out what the best treatment is for obsessive compulsive disorder or OCD. And if you've been affected by the issues in this programme or would like further advice or help, please consult your GP or mental health professional.

29:33 - How sleep helps you learn

Could sleep help you boost your learning power? Nerve cells in the brains of mice grow new connections as they sleep....

How sleep helps you learn
with Peter Oliver, Oxford University

Could sleep help you boost your learning power? Sleeping Student

We've all heard the phrase "sleep on it", and there are many anecdotes from people such as students and musicians who find that getting a good night's sleep after studying or practising helps with learning.

But what's going on in the brain? Its secrets are now revealed in research from scientists in America and China, showing that nerve cells, or neurons, in the brains of mice grow new connections as they sleep that help them learn.

Kat Arney caught up with sleep scientist Peter Oliver from Oxford University, who started by explaining what's going on in our brains as we visit the land of Nod.

Peter -   The brain is very active when we're asleep and that's really the first point.  So, when we're asleep, it's not like the brain is switched off.  It's firing all the time, making new contacts.  And these new contacts the brain makes during the night and how the cells connect to one another, that's often called memory consolidation.  The idea is that when we're asleep, the brain is active.  If you like, it's replaying events that have happened during the day and this will help us remember things for the future - both the next day and also for longer term.  The case is memory consolidation.  So, this is a fairly new topic and a slightly controversial topic.  The evidence for memory consolidation is quite new in the field and relies on very complex experiments, but certainly true.  There's lots of evidence that sleep is a very active process.  Sleep is really important for our brains and has a very useful function.  These new connections made when we're asleep are really important for us.  That's really the background behind it.

Kat -   So, what have the researchers done in this paper?

Peter -   So, what they've done is they try to understand more a bit about the structural elements in the brain that they change when somebody has carried out as task.  This is actually using mice.  So, the mice have been trained on a simple - what's called a motor task with simple movement task.  They were taught to walk on a rotating rod.  It's a bit like a toilet roll holder connected to a motor and then it rotates slowly.  This allows the mice to walk along - very simple, very simple task.  But also, as they're doing the task, the brain is having to learn the task and make new connections.  They showed that the brain was actually changing its structures, very subtle changes in a very small group of new cells in the brain.  So, neurons in the brain were changing.  And then what they did is they let the mice have a normal night sleep and they see what happens the next day after a normal night sleep.  What they found is that these particular structural changes were still there after they'd had a normal night sleep.  So the fact that the neurons had been firing when they're asleep was promoting these new, very small and subtle but important structural changes in these neurons.

Kat -   So, these are like little fingers that help the nerve cells talk to each other.

Peter -   Exactly right.  So, it's actually crucial.  So, as you know, the brain is very, very complex.  There's probably a hundred billion neurons in a human brain and it's incredibly interconnected.  So, many neurons are interconnected to many, many others.  It's a bit like you're standing in a large crowd and you decided to hold hands with the person next to you.  You have to put your hand out first to do that and then that person will put their hand out and then you'll hold hands.  And then you might do that to someone else.  So, this is the way the connections are made in the brain.  So, if you like, there's a big crowd of people all holding hands in different combinations to allow people to communicate.  That's really what happens in the brain.  So, the important thing in these studies that they show that having a normal night sleep actually promotes these new connections in the brain.  And these new structures, these new connections are maintained for several days later.  That's really the key thing.  I think why this is important is because it's now shown in real detail how flexible and how new structure changes occur during sleep and how that can affect memory in the future.

Kat -   How do they know it was definitely sleep that was doing this?

Peter -   So, what they did under control for sleep is they actually carried out some sleep deprivation experiments.  It's where they will actually make sure that the mice don't sleep.  Normally, they're keeping awake and they carried out experiments in parallel.  What they showed, that there was actually a reduction in the amount of this spine formation or reduction in the structural changes in the brain when the mice had had disturbed sleep.  So, there's definitely a strong link then between the quality of sleep, the type of sleep that these mice were getting and also, the amount of these increase in these dendritic spines that are occurring overnight.  So, there's definitely a strong link between the type of sleep, the quality of sleep, and also, the structural changes in the brain.  So the idea is, the better sleep you have, the longer sleep you have, and the more sleep you have in what's called the deep sleep or slow wave sleep, this is more likely to allow new connections in the brain to occur.

Kat -   Now obviously, when a story like this hits the headlines, people are like, "Is this relevant to humans?"  These studies have been done in mice.  Do you think they are going to be relevant to humans?

Peter -   Yes, certainly.  What we know about the firing of the brain during sleep is very similar in most mammals.  The structures of the brain we looked at in this particular study are very similar to those found in humans.  So, there's a direct correlation between the structures that are being examined.  Certainly, a rodent's sleep is very similar to a human's sleep in terms of the type of sleep they get.  The different phase of sleep are very similar, so although mice are nocturnal compared to humans mostly being living during the daytime that their data has lots of direct parallels with humans.  Certainly, we know from lots of work that having good night sleep is very important for humans, both for their physical health and also for their mental health, and for their formation of new memories.  So certainly, this has direct and very important implications for humans - both in disease situations, but also in just normal daily lives.

Kat -   So for example, I'm a musician.  So, if I was trying to learn a piece, I should do some practice and then sleep on it and do a bit more in that and that would be better than just kind of keeping going on it.

Peter -   I think that's kind of what this ton of work is pointing towards.  I think there's a long way to go to really correlate directly between a physical activity one day, a good night sleep and improving your performance the next day on very complex tasks.  But certainly, this data shows a very simple task can actually be related directly to changes of the brain which might help you remember things in the future.  Certainly, with the world cup coming up, if the England team are practicing penalties every day as apparently they are as I heard from Steven Gerard today, and then they sleep really well and practice the next day and then sleep really well the next day, it doesn't really guarantee they'll score when against Italy or one of the other teams in the future.  But certainly, I hope the team is sleeping well this week.

[Snoring recorded by Popup Pixels]

36:31 - How best to treat OCD?

How best to treat OCD?

We next return to our panel with your questions. Pushkar Nareshta got in touch asking, "What's the ideal treatment for OCD or obsessive compulsive disorder?" First up, Roger.

Roger - OCD, obsessive compulsive disorder can be a very difficult and debilitating issue. Some estimates suggests that 3% of the population have OCD at some point in their lives. Often, it can be recurrent as well. It tends to occur when we have full images or repetitive ideas that come into mind intrusively and are quite distressing. In order to try and deal with them, often, we feel compelled - it's where the compulsions comes in - to do certain things, perhaps engage in a ritual whether that's internal psychological, whether that's something external in the environment.

Hannah - So, the typical stereotype of OCD if you like might be someone that has a fear of contamination with bugs in the environment. And so, they might compulsively wash their hands and wash light switches for example and everything around them in order to take control of those bugs and make sure that they're wiped out and therefore, they're safe.

Roger - That's often the kind of way it work. although of course, it's not restricted to it, while it's very common to have concerns about contamination and dirt and so forth. There are many other areas that it can affect in life. At worse, people can be spending a lot of their waking hours concerned with a form of ritual. So, it can be a real problem. But the good news is, is that there are treatments of OCD. So, part of the treatment is going to be, exposing one's self to the feared stimulus. So, you might be the contaminations around like a dirty door handle and then resisting the urge to perform the rituals to it and overtime, very often, the level of anxiety drops down and some progress can be made. Typically, what we'll try and do is clinically, is take a particular line of work around a ritual and get the number of rituals down and achieve some symptomatic reduction that way. And at least 50% of the people respond well. There's also evidence that SSRIs can be held for either as a standalone treatment or combined with psychotherapy.

Hannah - So, that's a type of anti-depressants given with the cognitive behavioural therapy where you expose the thing that you're frightened or obsessive about. Martin, do we know much about what's going on in the brain of people that are affected by obsessive compulsive disorder?

Martin - Yes, so those are basic circuit in a brain that's involved in normal behaviour and it involves an interaction between deep brain structures and prefrontal cortex. This is called prefrontal basal ganglia loop system that's involved in normal behavioural control. We're all engaging in that system at the moment. I think the general idea is that there is disruption to the system, the information process and capabilities of the system and patients with obsessive compulsive disorder. I think most research nowadays is trying to really focus in on which part of that system or which part, constituent parts have aberrant physiological behaviour and conditions like obsessive compulsive disorder. Essentially, that's all as it's a shift in normal behaviour and so, it's a shift in a normal circuit in the brain and I think a lot of treatment is trying to re-establish the balance in these circuits.

Katie - In fact, the idea of putting an electrical impulse through the skull and into a very specific part of the brain and there's actually this being looked at in OCD currently in an area called the ventral striatum which is involved in the loops that Martin was just talking about to alter the connectivity and to alter the activity going on in the brain there. But I think again, it's important to know that obsessive compulsive disorder has many different symptoms. For each individual, it can present very differently. Some people, it really is about obsessive thoughts that can keep re-entering the brain and for other people, it comes with those rituals and those behaviours. Any idea of a best treatment, it's never a 'one size fits all'. There's multiple different treatments available and it's about working with the clinician to find the one that works for that individual.

40:33 - Do we have conscious control of our brains?

Do we have conscious control of our brains?

Teo Gibson has been in touch saying, "I'm pretty sure you tackled the myth of humans using only 10% of their brain, but how much of the brain do we consciously have access to control over? What's the ratio of autopilot to consciousness?"

Martin - I'm not sure what the ratio is. I'm not sure if anybody - it's a very good question. The question itself actually strikes at the heart of this myth, but we have to be aware that our brain is very busy constantly. You know, the fact that I'm sitting here upright at the moment is - thanks to my brain power, to process that, I'm not - well, I wasn't thinking of it until just now. And breathing and heart rate, and also, sensory process and so, I'm looking at you at the moment. I'm aware that you're in front of me. I'm aware this microphone is in front of my mouth, but if something was to happen in my peripheral vision or if a noise is to happen behind me, I would react to that. And that's the angst of my brain unconsciously processing this external environmental space even though I'm not consciously aware of that. That's also true for these sort of internal signals that I've just referred to as well.

Roger - There's a clinical aspect to this as well because quite often, we'll feel symptoms whether it's kind of feeling low, anxious, depressed or otherwise, stressed, but we might not know consciously actually what's driving that. There are ways of working with that stuff now. So, whether it's for example, hypnosis sometimes can be used for.

Katie - I think this question then really is all about attention and what we are consciously attending to at any one time. So, as Martin was saying, there's so much processing going on. It's there if we need to use it, but what we're actually attending to is the thing that we focus on and the thing that's useful to us at that time. and there's also other things that we attend to until we've learned it and then it enters them on your autopilot memory as well. So, the brain is working away, but we're choosing what we attend to and this is actually been useful in treatments as Roger was saying, including like mindfulness and those sorts of ideas. That can even be applied to things like eating behaviour. If he sit in front of the tele and eat food, you don't realise quite how much you're eating. You don't attend to it and you don't feel full so quickly whereas if you focus on what you're doing, you sit down on the table and you eat, you tend to eat less.

Hannah - The myth that we only use 10% of our brain, well that's actually coming from imaging studies where you get people to do particular tasks, concentrate on something and you can see the oxygen levels of their blood rushing from some areas of their brain to other areas of their brain as they concentrate and attend to a particular task. But obviously, all of the brain tissue is needing a small amount of oxygen at any time in order to keep those cells alive and to keep things ticking over even if you're not consciously aware of that.

43:14 - Why do I hear things that aren't there?

Why do I hear things that aren't there?

So now, we attend to the next question which comes from listener Kris Oliver who's been in touch saying, "Why do I hear and see things that aren't there?" So, he's a music composer and at times when he's relaxed or he's just about to go to sleep, he can bring voices or auditory hallucinations into his mind so he can hear things that other people can't hear. He's asking what's going on there. Apparently, this isn't uncommon. So, I spoke to the head of the department of psychiatry at Cambridge University and he said that a recent study that's been published indicates that about 10% - so, 1 in 10 older teenagers will actually experience the same thing, these hallucinations even though they're not actually psychotic. So, they haven't got Schizophrenia but they are experiencing things that other people don't. So, what's going on there?

Martin - So, conscious perception of sound results from the processing of sound waves, either the brain's auditory system, in the same way the conscious perception of colour results from the processing of light waves and particles by brain's visual system. These systems will be highly sensitised and people like Kris who engage these systems in a frequent and highly specialised manner, these systems can evoke a conscious perception like a memory trace offsets (44:33) and this is partly why people have had limbs amputated feel phantom limb sensations such as a natural pain in say, a hand has been amputated. That's because despite of the limb being gone and the brain apparatus is still there, so that just fire off and evoke these sort of conscious perceptions of something that's not actually there.

Hannah - So, he's kind of almost developed a highly sensitive or maybe he was born with a highly sensitive kind of auditory perception of sound system in his brain and there's nerve cells that are being activated by things that he's not even consciously aware of. Are the sounds actually there or are they coming from his imagination from his head?

Martin - I think maybe a good way to think about this is the old adage of, if a tree falls in the forest, nobody is there to hear it. It doesn't make a sound. The answer is actually quite simple. It doesn't release sound waves into the environment without a nervous system to take those sounds waves and then process those sound waves also through you know, in our ear, through our auditory system inside of the brain and then into the brain, we actually would not have what we know to be conscious perception of sound. So yeah, he's experiencing I guess as the same system that his brain is becoming active without the environmental stimuli.

Katie - I mean, these experiences is a lot more common than many people expect. There's an understanding of mental health disorders as being extremes of experiences that people in the normal population on the healthy population experience. But it's when these become problematic and affect the functioning in daily life that they become what we would refer to as a disorder. One of these continuums is known schizotypy. It refers to the fact that many people in the general population sometimes experience similar types of experiences. And these people have Schizophrenia so hearing and seeing things that aren't there and hallucinations which can happen in any sensory modality including touch, taste. Some people are just more susceptible to these experiences than others. So, it's a sort of scare with some people being more and some people being less Schizotypal. It's important to emphasise that having this experience is not the same thing as having a disorder. There's a number of theories as to why people have hallucinations. One of these popular theories suggest that it might stem from the sort of heuristics and shortcuts predictions that people's brains use to help them interpret everything that's going on around them, and to sort of select the information that's useful to them. So, you monitor what your actions are, your deliberate actions, and use that to predict what you expect from say, your own feedback.

Hannah - And Kris suffers from these hallucinations either auditory sound hallucinations at night. So, it's not intruding on his day to day life. It's an experience that he's also got an insight into. And so, he can almost predict that it shouldn't be there in the environment and it's unexpected that it is there in the environment but he has that insight to know that it's not somebody outside in the space, telling him to do something or producing a particular sound that might frighten him.

Roger - And that, a particular kind of again, manoeuvre can be very useful clinically. It's almost like a mindful detachment kind of mode. So, whatever it is, it's just noticing it and letting it go rather than dwelling on it or interpreting it, just allowing the phenomenon to be there and then letting it pass. That can be really helpful.

Martin - I think it sounds so interesting Kris this just happens just before he is falling asleep because I kind of personally know when I'm falling asleep because my thoughts get very abstract. Again, I'm aware that I'm not going crazy. The thoughts do get very abstract and wild and strange to me. I've got used to that and actually, I get quite happy when that happens because I think, okay, I'm falling asleep now.

Roger - I think there's a school of thought around hypnosis that when we're in that kind of trance like the hypnagogic type state, conscious controls come off a little bit. Say, I might think I'm actually playing the centre forward for England, but of course, it isn't true. As you say, a well-recognised phenomenon.

48:35 - Do we have free will or is life determined?

Do we have free will or is life determined?

And very last question for the show, Tracy Morter has been in touch with biggy. She wonders whether there's such a thing as free will. What are your thoughts on that? Martin, do we have the choice to make decisions in our life or is it all pre-determined?

Martin - So, it's a great question. If we could answer it, here and now, we would all be getting a Nobel Prize. For me, the Holy Grail of basic neuroscience research today and that pun was intended for centuries of the study shall we say of free will. It has really been confined to the area of philosophy and theology, but I think now, it's almost impossible to think about the actual free will without some sort of neuroscience and put without some sort of physiological appreciation of decision making mechanisms. And that central question, are our decisions a consequence of simply processing input through our brains resulting an output which would be our behaviour or derived from some sort of internal signal that comes from, where we don't know. And so, as a neuroscientist, the latter seems more unlikely because it seems mythical in a way whereas in internal signal coming from. However, we can absolutely say that that's not the case until we can answer or provide evidence in favour of the former, our behaviour as under external environmental stimuli.

Hannah - My own view and this is just a personal view is that, our brains are neural circuits in our mind are formed based on our experiences. Those circuits change structure based on what we're exposed to and then the structure of those circuits actually decides for us how are we going to react to a given situation. So, we'll react to a given situation based on our prior experience of the world around us and how we perceive the world around us is based on our prior experience. And so therefore, everything almost is pre-determined. That's just my own personal view. I don't know whether you've got anything to add to that.

Roger - It's a great question and I think if will without free and decision making without pure. I for one will be out of a job tomorrow because I think we're not all Bertrand Russell purely chronological beings. I think you see that very much clinically because how we're feeling and what's going on in our lives just go back to your point about prior experiences. In effect, what we want to do and what we think we're going to do in our decision making can affect enormously. One of the things that we see clinically is when we work with issues, both at the current kind of symptoms level and that deep level going back is often, you do with say, past trauma or effectively, it can really free up more effective decision making processes and may help people to think more clearly about actually what they do and want to do with their own free will.

Katie - I mean, I think you only need to look at the things that people working in marketing use to encourage us sort of this nudge techniques to encourage us to buy. I mean, things as simple as - in the UK, we would normally scan a shelf from left to right so you put the product that you really want someone to choose on the right hand side. You know, these sort of very simple things that so powerfully affect even very small decisions that we make. I think you're right in terms of the experiences that we have been exposed to will affect the way our brains develop. That will also affect the experiences that we then go on to have in the future and the situations that we choose to be a part of - and yeah, it sort of has a cycle.

Martin - Without trying to be controversial, from a purely neuroscience perspective, as conceivable that what we have developed through evolution with the complexities that have developed in the human brain have produced the illusion of free will, this idea that we have free will which sort of drives us forward and gives us things like hope. Maybe to put that more on a physiological basis, our prefrontal cortex is the most evolved part of the human brain compared to other species. What we have evolved that other species don't have is things like appreciation of beauty and creativity, and we can produce beautiful music and works of art, and argue with personality. Again, it's conceivable that this could be a consequence of this very complicated, intricate network of neurons and the brain. So, it's again conceivable that the input, the environmental information that we receive from birth or even pre-birth is processed in such complicated manner that the output that we see as behaviour is simply an output of a very, very complex piece of machinery. I mean, that would be the deterministic argument against the existence of free will. But whether or not that's the case, we really don't know.

Hannah - And so, this big prefrontal cortex that humans have evolved to have is basically just a big processing unit that allows us to bring in lots of information from prior experiences and prior environment and current environment, and process that quickly in order for us to come up with a decision outcome.

Martin - That could be the case.

Katie - I mean, I also think it depends at the level that you want to analyse this question or look at this question in terms of things like vision. I mean, we don't see every single thing that enters our visual field and we use some sort of quite high level expectations and impose these expectations and predictions to actually see things sometimes that aren't - that make the most sense in terms of what we're expecting, but aren't quite exactly what's there. I mean, the hollow mask illusion which you can see on YouTube is one of them. I mean, yes, these things might have huge influence on the decisions that we make. But we still have that feeling that we're doing things and those feelings and that hope, and that anticipation, and the idea of weighing up those decisions.

Hannah - And to end the podcast and the slightly more positive hopeful note.

Roger - From a clinical perspective, one of the things that we're interested in is increasing people's options and choices because one of the things we know is when we're stressed, low or depressed. We often feel that we've got very constrained choices. At worse, we could feel trapped and that's a very unpleasant way to feel. So, there are various ways of either kind of manually setting up the options that we might choose to follow or using things like meditation that produce changes at a neurophysiological level via which means, we can see that there are different avenues, new and different things that we can do that can also lead us to feel better. So actually, it's taking into account where there might be a process that are in there, but it's actually about looking at the complexity, the whole context to see the available options that are there for us.

Hannah - And that's all we have time for this month unfortunately. Thanks to all those who took part in the programme, Martin O'Neill, Katherine Manning, Roger Kingerlee, Liz Fraser, Kat Arney, and Peter Oliver. I'm Hannah Critchlow and we'll be back again next month with the next Naked Neuroscience podcast to open our minds. I'm going to be reporting from Milan with a breaking hot neuroscience news that's being presented at the Federation of European Neurosciences Conferences. You can subscribe for free to Naked Neuroscience podcasts on iTunes or you can find us on thenakedscientists.com/neuroscience.

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