Neuro highlights: SNAP, tickles, and unpopular beliefs
For April's episode, James Tytko brings you the latest and greatest in neuroscience news and views. First, we're probing a touchy subject, finding out whether our tactile sense might be the most underappreciated of all. Then, the sequence of genes responsible for cognitive impairment in those with schizophrenia and ageing reveals new avenues for research. And a bit later on, how the cultural convergence many psychologists predicted as a result of globalisation is not coming to fruition...
In this episode
01:01 - Human (and robot) touch has health benefits
Human (and robot) touch has health benefits
Julian Packhesier, The Ruhr University Bochum
Of all our senses, perhaps the least well understood is touch. The importance of which became apparent when many of us were no longer able to hug or be hugged by loved ones during the pandemic. Now, a growing body of scientific evidence suggests that regular, physical contact with other people can confer a whole raft of health benefits: from reducing physical pain and stress, to feelings of depression and anxiety.
This led Julian Packhesier from The Ruhr University Bochum and colleagues to conduct a meta-analysis of research from this flourishing field. They sought to describe the factors most responsible for the effectiveness of touch. James Tytko started by discussing how at no stage of our lives is this dependence on touch more keenly felt than when we are first born…
Julian - We do not have fully developed senses, for example, for vision when we are born and the vision is very blurry. So the way that the word is interacted with is often through touch. What is the first thing we experience after we are born? We are being cradled usually in our mother's arms, and that is something that is a crucial experience for our bonding to our parents and this continues throughout our whole lifespan, essentially. We make emotional bonds and we deepen them through touch and we sometimes forget how important it is. When you think about, 'Which sense do I not want to lose?' most people would say, of course, I never want to lose my eyesight. But if you couldn't sense anything anymore through your skin, that would be extremely detrimental for our wellbeing and it would even be hard to conceive.
James - That's a good way of putting it. I suppose it's the most intuitive way we can communicate.
Julian - Exactly. After we have learned how to communicate through language, of course, it becomes less critical to also communicate intentions through touch. But communicating emotions through touch, that is something we keep throughout our lifetime. Our intimate relationships are usually critically built on exchanging touch both to deepen affection but also to just express how you feel, right?
James - So we're talking now here in terms of the health benefits of a life filled with plenty of touch. Let's talk about another one, I'm thinking mainly of the way it helps us manage stress. I wonder if you could unpick the mechanism by which touch helps us deal with that particular affliction.
Julian - So the mechanisms are still under investigation, but what we know for sure is that touch releases the hormone oxytocin. Oxytocin is quite well known as a hormone. Many people have deemed it the so-called 'love' hormone. Of course this is a simplification. Oxytocin has a wide variety of functions and the functions are not yet completely understood. But what we do know is that intimate and affectionate touch releases this hormone and if this hormone is released in the body, it has both analgesic properties - so it can reduce pain - and it has the property of reducing anxiety and stress. The way it reduces stress, so the mechanism behind it, is that it actually blocks the building of the stress hormone cortisol in the body. This is how, on the hormonal level, we know that touch can ultimately reduce stress and can relieve pain through the release of this hormone.
James - One of the other things that your study pays particular attention to is the impact of who is doing the touching and whether that has an impact on these health benefits. What were your key findings there?
Julian - Yeah, the findings in that regard were particularly interesting to us because our intuitive understanding initially was, if it is someone who we feel more connected to, someone we know, that should probably increase the benefits of touch compared to someone where you just receive, for example, a massage at a professional physiotherapist or something like that. In adults, we actually found that it did not make a difference. So if you are seeking touch, obviously always with consent, the effects were on average the same. Why that is is still a little bit unclear to us. We thought of some potential mechanisms that could underlie it. It could be, for example, that someone who applies a professional massage, someone who really knows, 'Okay, this is the area I need to touch in order to make people feel better' if they are, for example, having pain in a certain region, they just have more expertise in doing it. But this can be then counteracted by people who you have more of an emotional bond with. So even if they do not know exactly how to touch in a professional sense, there the emotional bond might actually be enough to then even out the lack of expertise of that person doing the massage.
James - There's another factor at play here which I wonder if your results reflect that when it comes to not being touched, you don't suffer these poorer mental health outcomes or health outcomes because you don't have relationships necessarily whereby someone might touch you. You don't have the same connection with friends or loved ones. Is that another factor here kind of complicating the picture?
Julian - That could very well be right. So people who are seeking our professional massages because they do not have access to touch in their everyday life because they are not, for example, part of an intimate social network, yes, they might then have a stronger longing for touch even by someone whom they do not personally know and then that might actually make it also more effective. That's a perfectly reasonable answer to this mystery that we are still facing in our study. We can just say, this is what we found and now more research is actually needed to understand why that is the case.
James - And then you also took this one step further and asked, does it even matter whether it's a person that's touching us or not? Tell me about that.
Julian - Yeah, that was also something that we were really interested in, especially since this field of touch research has developed more recently also in the non-human domain. So many studies in the recent past have actually looked at novel social robots and also touch interactions which, for example, a body pillow, a weighted blanket, hugging devices that you can really embrace and that feel more natural, more human. We were really interested in it. Can we actually substitute human touch? And the results were also extremely surprising to us because our intuition before was probably that it would not reach the level of human touch but, actually, for physical health at least, when it came to reductions in stress hormones, reduction of pain and blood pressure, we actually found effects that were on par with that of human touch. Where robots and also these objects were not as effective was when it came to the improvement of mental health conditions: so feelings of anxiety and depression, negative mood. There, using something that substitutes human touch probably is not as advisable at the current moment.
James - Yeah, I'm not sure how to feel about that. The fact that they were able to confer the same physical health benefits but, is it just a matter of time as society becomes more comfortable with the prospect of having a relationship with a robot that perhaps will reach parity on those fronts? Fascinating finding nonetheless.
Julian - And we really want to understand why that is and there are reasonably good explanations, right? So one thing that is missing when you touch a robot is skin-to-skin contact. And our study has also shown that in humans, if the skin-to-skin contact is missing, the mental health benefit seems to be lacklustre. So something seems to be important to us to touch other people's skin, feel their warmth, feel their humanness in a sense. And another factor is that if you are engaging in touch with a social robot, even though they become more human-like as technology develops, if you do not have an emotional connection to these robots, they might still seem strange to you. Let's see how society develops in that regard, but that could also be a critical factor as to why mental health benefits in particular were not as improved if you used a non-human agent, essentially.
10:23 - The striking similarity between schizophrenia and ageing
The striking similarity between schizophrenia and ageing
Stephanie Brown, University of Cambridge
A natural part of healthy ageing is to experience mild cognitive impairment. It might mean that we suffer a slight decline in our ability to remember certain things or complete certain tasks as we get older.
Interestingly, scientists from the Broad Institute of MIT and Harvard have observed a striking similarity in a sequence of gene changes that leads to mild cognitive impairment in those who are ageing, and those living with schizophrenia - a psychiatric condition which can have much more debilitating symptoms. The University of Cambridge’s Stephanie Brown has been looking at the study for James Tytko.
Stephanie - Schizophrenia is a serious mental health disorder that affects 1 in 300 people globally and symptoms can be quite debilitating. These include things like hallucinations, hearing voices, and believing things that are not reflected in reality. Cognitive impairment is also quite a common symptom and people can have trouble remembering or learning new things or concentrating and making decisions, but it can also include things like subtle personality changes or just difficulty in general doing the tasks of the day.
James - Is schizophrenia a genetic condition?
Stephanie - So that is a very interesting question and the answer is yes and no. It does tend to run in families, but there's no one gene that's thought to be responsible. This actually relates to something known as polygenic risk where a collection of small changes in the genome can contribute to a higher overall increased risk of developing the condition. But it's also very important to recognise that the environment can also play an important role and factor into triggering or increasing risk for developing schizophrenia.
James - Interesting. But it's this cognitive impairment symptom of the condition we are thinking about for the purposes of this study. In the news recently, there's been quite a lot of coverage hasn't there of the cognitive functions of the presidential candidates in the US and people have been pointing to their age as a contributing factor as to why they might not be where they should be. What's the science there?
Stephanie - So firstly, it's normal that cognition will get a bit slower or less effective as we age. That's actually healthy ageing, that's completely normal. But as people get older, they also become more at risk for something called mild cognitive decline and this can affect memory and the ability to perform tasks. It doesn't necessarily have to be debilitating, but it can develop into more serious neurodegenerative diseases like Alzheimer's disease. And similarly to schizophrenia, cognitive impairment in old age can also be inherited and some specific genes can increase risk, but there's no one gene that's responsible.
James - So what have these scientists found out about how cognitive impairment happens in these two groups of people: those with schizophrenia and those who are ageing?
Stephanie - So this has to do with the way that certain genes are expressed and the discovery that they are coordinated in two brain cell types called neurons and astrocytes. Neurons connect with other neurons at synapses and carry messages from one part of the brain to another and, thanks to previous studies, we actually knew that genetic factors related to synapses and neurons were linked with schizophrenia. And astrocytes are really the kind of support cells of the brain.
James - Yes. Astrocytes are the most numerous cell types in the brain, aren't they, performing lots of jobs in keeping our nerve cells working the way they should?
Stephanie - Yeah, that's right. So, in this study that was published in Nature, the team describes how they analysed gene expression in more than a million individual cells from postmortem brain tissue from 191 people. They found that in individuals with schizophrenia and in older adults, astrocytes and neurons reduced their expression of genes that support the synapses compared to healthy or younger people. They also discovered that when neurons decrease this expression of certain genes related to the synapses, astrocytes similarly changed their expression of a distinct set of genes that support the synapses.
James - So the expression of these genes is somehow synchronising in these fundamental cells in the brain. That's really interesting.
Stephanie - The team called this coordinated set of changes the 'synaptic neuron and astrocyte program' i.e. 'SNAP.' And even in healthy young people, the expression of these SNAP genes always increased or decreased in a coordinated way in their neurons and astrocytes.
James - What sort of doors does this open research wise for the understanding of cognitive impairment? Could this be a really important step for mitigating the impact of it for whomever is impacted by it?
Stephanie - With a better understanding of SNAP the authors are hoping that it might possibly be useful to identify life factors that could positively influence SNAP and develop medicines that could help stimulate SNAP as a way to treat cognitive impairments of schizophrenia or help maintain cognitive flexibility in people as they age. And, as you say, it could have wider implications as well.
16:21 - Cultural values are diverging around the world
Cultural values are diverging around the world
Dan Medvedev, University of Chicago Booth School of Business
Values. They form the centre of how our societies function. They dictate laws, how we distribute resources, who we go to war with, and - on a more micro level, how we go about our daily lives.
Many psychologists assumed that rapid technological developments would make the world an increasingly homogenous place, and that cultural values across the globe would begin to converge. But new research published in Nature Communications has found exactly the opposite. To find out more, I went to meet Dan Medvedev who was one of the lead authors on the study…
Dan - The values that actually we show the biggest effect for, the biggest divergence for, are values that are related to how people perceive and treat groups and cultural practices that somehow deviate from the norms. We're talking about things like acceptance of homosexuality, acceptance of divorce, euthanasia. These things that maybe before, in Western societies at least, we would think of as in some way deviant.
James - One of the hypotheses around this topic is that, with globalisation, with economic development across the world, with better means of communications between cultures, people thought we might start to see our values assimilate and become one.
Dan - Yeah, that's right. I guess a pretty famous example is Francis Fukuyama's book where he predicted the ‘end of history.’ The idea, or the reason for the end of history was that, after the spirit of the Second World War and Cold War after, now that countries are beginning to gain prosperity - which is true, the poorest countries, the majority of them, have gained in wealth - they thought it was just a matter of time before more and more cultures would adopt more of these 'western' or 'European' values.
James - Some really big ideas, some very grand theories, there. So how do you do your job? How does one go about objectively analysing whether cultures are diverging or converging? What's the process?
Dan - There have already been studies that looked at just some values, only looking at a few countries. I think what we did is different in that we analysed 76 countries, almost half a million people, and we did it for 40 different values. Not all of them are related to these values of acceptance or tolerance that some researchers call 'emancipative' values. What we do is we take data from this survey called the 'World Value Survey,' which is probably one of the biggest and most influential and important instruments, sources of data, for looking at values over time in many countries. What they do is they survey a lot of people in a lot of different countries in the world around every seven years. They are all representative samples, which means that they try to emulate the actual demographic composition of a country, and that goes back at least to 1980 to the last wave of the survey, the last time they collected data, which I think ended around maybe two years ago.
James - So when you looked at the survey results across the 40 year time period, have values been converging or diverging since that time?
Dan - We find pretty strong evidence for overall divergence in values. Not all values have been diverging. For example, people around the world tend to agree more and more that there will be more emphasis on technology in the future. Values that have been diverging the most, which is the majority of values that we've surveyed, they have to do with the dimension that we previously talked about that refers to importance of tolerance and self-expression. The value that has diverged the most is acceptance of homosexuality. A lot of them also have to do with somewhat similar practices such as divorce, abortion, euthanasia. Some of them have to do with the importance or relative rejection of qualities such as, for example, obedience in children. Like, is it important to instil obedience of authority in children? Now, countries disagree on that much more than 40 years ago.
James - In terms of these diverging values, I've got a hunch that they would be diverging more in countries in different parts of the world and perhaps the divergence would be less strongly felt in countries that neighbour each other. That's just an intuitive guess. Would that be a correct one?
Dan - Yeah, also a couple of things, there. So we actually see that around 1980, for example, Europe and Asia are pretty close to one another on the acceptance of these sort of more liberal western values. Now they are worlds apart, you can say. But for example, South America was also pretty close to Asia and Africa: pretty low on these emancipative values, but it has become significantly more liberal, emancipated, western, whatever you want to call it, but Asia and Africa have not. So there's also this pretty big difference if you just look at continent level. I think that the second most important finding in our paper is that if you take a really wealthy country and a low income country, the likelihood of them sharing similar values is much lower than if you take two countries that have similar levels of wealth, that has always been the case, but in these past four decades we've been observing a trend where geographical proximity, how close the country is geographically to another country, has been becoming a more and more important predictor of sharing values. So we do see overall global worldwide divergence of values, but regionally we see the opposite pattern where, regionally, the values are converging and becoming more similar.
James - We've talked about how economic development is a big determinant in these emancipative values and how much they're taken up by the population of a country. Is that a consistent finding around the world?
Dan - So we do see that in some countries in the west, particularly in Europe, it is true that as they grow wealthier, they do develop more emancipative values, values that focus more on self-expression and tolerance and acceptance. But this does not seem to be the case in a lot of other world regions, notably in Hong Kong and in Singapore, that have increased their GDP per capita a lot in the past four decades. We do not find the same pattern of moving towards emancipated values.
James - And my final question, because I know it's not one you particularly set out to answer over the course of this study, it's the question that I've been refraining from asking, which is why is this happening? Why is it that the modernisation theory that you outlined at the start has not come to fruition? And why is it that as economic development has touched all the corners of the world, it's gone down this route of the traditional values of that country becoming more entrenched?
Dan - Yeah, I mean this is such a broad question. I don't have one definite answer. I think we just assumed that consumption of western media and western values would lead to people adopting them, but that might not be the case. Hollywood, right? Hollywood movies are being watched all over the world. A lot of people are listening to Ariana Grande or Taylor Swift. But people can go and watch RuPaul's Drag Race and either reject it or completely not change the way they think, for example, about self-expression or LGBTQ rights. There’s a theory by this scientist named Tomlinson, he was thinking about how globalisation, which is commonly seen as supposed to be a force that was supposed to unite different cultures, he thought the globalisation might actually do the opposite. It might create this incentive, this type of psychological and sometimes political drive to create a particular cultural national identity for itself. You have to establish or reestablish yourself as a country that also has a separate national cultural identity, and to me it's also interesting that it seems like this divergence at least is co-evolving, right? Co-occurring with also a general rise in anti-western sentiment in a lot of parts of the world right now.
25:26 - Brain to Z: C is for Consciousness
Brain to Z: C is for Consciousness
Time for more Brain to Z, this time looking at 'consciousness.'
Put simply, to each and every one of us, consciousness is everything. It’s our sensory experience: sights, sounds, and smells. It’s a sense of our body and feelings of pain, and pleasure. It’s our emotions and our memories.
By looking at the activity of the 86 billion neurons inside the human brain, neuroscientists have been able to draw correlations between bits of brain activity and given conscious states: the process by which decay in your molar leads to a feeling of toothache, for example, can be objectively observed and mapped out using brain imaging.
But for many researchers, just knowing that certain brain areas go along with certain aspects of consciousness doesn’t explain why physical processing in our brain should lead to any feeling at all. This has been dubbed, by influential philosopher and scientist David Chalmers, the ‘hard problem of consciousness,’ and something researchers are beginning to develop interesting new theories for.
The reductionist, brain based theory of consciousness argues against the existence of the so-called ‘hard problem’ altogether; that the concept of subjective experience is unscientific and, ultimately, illusory. Such theorists posit that consciousness is a property of physical matter, the functions and behaviours of which may one day come to be understood in terms of the fundamental laws which we understand to govern the universe.
Others believe, much like at previous points in the history of science, instead of working within the current limitations imposed on what we understand, we need to introduce new fundamental laws in order to incorporate room for consciousness. Just as James Clerk Maxwell could not see a complete explanation for electromagnetic phenomena within the confines of Isaac Newton’s laws of motion, so he presented electrical charge in what came to be known as the second great unification in physics.
One radical, ancient, and now revived theory of consciousness is that of ‘panpsychism;’ the idea that everything has a degree of consciousness; from the intense information processing of the human brain, to less complex processing in animals, to primitive precursors to consciousness present in the simplest parts of matter.
In this vein, in 2004, Guilio Tononi proposed integrated information theory, a theoretical framework which posits that consciousness arises from the integration of information within a system, rather than from the individual components themselves. IIT describes a mathematical model which quantifies the level of integrated information in a system, whereby a system with a high “phi” value is considered to have a high level of consciousness, like us humans. Critics have pointed out the challenges in applying the theory to empirical data and defining its terms precisely, while others have recognised it as a promising approach.
Controversial as it is, Tononi’s is but one theory from a flurry of activity in this field of cognitive neuroscience as the search for a fundamental explanation of consciousness goes on. While the challenges involved in studying this topic are great, so too is the potential prize. Understanding consciousness would be a key breakthrough in our understanding of ourselves and the universe.
Comments
Add a comment