Brainspotting: That’s not my brain!

telepathy

‘Neuroscience? Cool! So, can you read minds yet?’
It’s a truth universally acknowledged that a neuroscientist at a party will inevitably be asked this question. Along with several others – the answers to which should really be printed on a t-shirt, or at least a conveniently distributable business card (as you can tell, I’m a riot at parties):

  • No, it’s not (usually) brain surgery, actually.
  • For the last time no, that left brain/right brain thing is a myth.
  • No, no one knows what consciousness is.
  • You only use 10% of your brain at one time? That’s impressive efficiency. And here me and everyone else are using all our brains, all the time.

And, of course, no we can’t read your mind (at least not in the way you’re thinking). But we can read your brain.

karen-no

Or so it would seem, according to a study published this month, which used a brain scanning method called diffusion MRI to generate individual brain ‘fingerprints’. Diffusion MRI is a technique which visualises white brain matter (the bits of the brain which act as connecting ‘wires’ throughout it – they literally look white compared to the ‘grey matter’ that makes up the rest of the brain) according how much water is travelling through it. Brain imaging isn’t exactly news, but this study was different because rather than looking at a person’s white matter connecting different brain regions, they focused on how connected tiny adjacent 3D sections within the white matter were. In a nutshell: instead of looking at how a wire connects your computer to a plug, they were looking at how the fibres within the wire itself were connected. They were looking at something called the ‘local connectome’.

By narrowing down the focus to the local connectome it appears that we may be able to accurately spot unique differences between brains. Using computer-based methods to calculate how different any two ‘fingerprints’ they generated in this study from 699 brains were, the researchers were able to correctly tell if two ‘fingerprint’ snapshots of the local connectome were from the same brain or not with 100% accuracy, across 17398 fingerprint comparisons.

journal-pcbi-1005203-g005
Source: Yeh et al. (2015)

Not only this, but looking at brain connections in this focussed way might be able to tell us how a single healthy brain changes over time. Brains are nothing if not complicated: they constantly make tweaks and changes to how their different areas are connected in response to your experiences and how the world around you changes. So, not only is my brain different to yours – my brain will also be different to itself minutes, weeks, years from now. By comparing multiple local connectome fingerprints from the same brain – snapshots taken over time – the study found that connections were changing, and losing similarity from their first fingerprint at a rate where fingerprints were 13% less similar every 100 days  (see blue arrows in the image above for examples of changes). So, next time someone tells you ‘you’ve changed, man’ – yes. Yes, you probably have.

And sadly, before anyone gets carried away, although ‘brain fingerprinting’ sounds like something taken from a futuristic court room drama – there’s an obvious flaw to this being used as a means of criminal identification, ever. (‘Well, we’ve been doing a lot of thinking and…those are not the defendant’s fingerprints!)

At first, this might all seem a bit obvious. At any present moment, our thoughts, the way we behave, view and experience the world – and so, our brains – have been shaped by our own highly individual past experiences. We are unique. To illustrate this, identical twins are more similar than any 2 humans you might grab (with their permission) at random. But imagine if being an identical twin meant you not only looked identical to your twin, but you also had literally the same identical thoughts and brain processes constantly running in synch.

Yet, conflictingly, if you look at any 2 healthy brains they largely just appear to be squiggly lumps of jelly: indistinguishable. Even if you know what the different lumps and folds and bits are, your average brain has all of them so still looks largely similar to any other.

It’s a similar question to the one genetics has posed in past decades: how come I can share as much as 98.8% of my DNA with a chimp and yet quite obviously not be a chimp? We can spot differences between healthy and non-healthy brains (though this doesn’t mean we know what the difference means) but what about those tiny differences that make my brain mine and your brain yours? It seems that focusing on the local connectome, as these researchers did, might be one promising way of looking at this accurately in future, as well as for identifying differences in diseased brains.

Now all we need is a litmus test for spotting a neuroscientist at a party.

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I Ain’t Afraid of No Shrub

halloween-blog1Image: Pimthida, Creative Commons

On Friday night I saw a woman on the Tube dressed as what I can only describe as a shrub (bright green body stocking, and a lot of leaves. Everywhere.) No one batted an eyelid. Welcome to Halloween as we know it in London.

As much as we might pretend it is, Halloween these days isn’t about being scared. Not really. We dress up, go to parties and consume lots of sugar and alcohol – all things your average brain actually quite enjoys. Over the last month people have been ghosting the streets and silently terrorising McDonalds dressed as sinister-looking clowns. This craze allegedly began in the US, which escalated and made its way here to the UK, where it was initially underwhelmingly received but has since been linked to serious criminal incidents. Conversely, it’s safe to say Shrub-Woman’s admirable effort did not inspire blood-curdling screams and fleeing en masse. (Possibly this could just be a London thing, in which all outward expression of emotion on public transport is frowned upon so hard, if you were to attempt said frown (not in public, of course!) your face would become one permanent crease.) But, rogue clowns, edgy costume choices and British awkwardness aside, what would life be like if you didn’t have the ability to feel fear?

For patient ‘SM’ – a woman who is possibly the most famous patient in the field of fear and emotional neuroscience – this is a reality. As a result of the very rare genetic disorder Urbach-Wiethe disease, SM has extensive damage on both sides of the brain to a small, almond-shaped area called the amygdala. Although there are multiple brain areas involved in generating the overall, complex experience we know as ‘fear’, the amygdala is known to be a key player in this. Amongst other things, its role is to essentially get activity and communication going between several other brain regions. This all eventually results in the production of the chemical adrenaline, whose most notable work includes ‘racing heart’, ‘sweaty palms’, ‘jelly legs’ and ‘stomach butterflies’.

In what is now a famous case-study, scientists took SM to several locations that might normally be expected to provoke fear in an average human: a local exotic pet shop and a Halloween haunted house tour of Waverly Hills Sanatorium, reportedly one of the ‘most haunted’ locations in the US. At the first location, despite previously saying she ‘hated’ them, SM held a snake without hesitation and was noticeably drawn to the larger and more dangerous species in the shop – asking a total of 15 times to hold one! She even had to be stopped from touching a tarantula that was very likely to bite her. Throughout this experience, SM didn’t report feeling fear, instead explaining that she felt intense ‘curiosity’. I only wish I could be as cool when faced with an enthusiastic wasp at a picnic.

On the haunted house visit, SM walked ahead of the research group, encouraging them to follow her (as anyone who’s ever watched a horror movie knows, this character doesn’t usually last long). Ironically, she even managed to scare some of the actors hired to jump out at visitors with her unexpected behaviour, approaching them to poke at and speak to them (so on second thoughts maybe this is a good tactic – update your zombie apocalypse contingency plans accordingly). Throughout the experience SM reported feeling only an intense excitement, but not fear. It’s important to note that other than her irregular behaviour in fear scenarios, SM is otherwise able to experience all other emotions normally, and is aware of what fear is as a concept for those of us who experience it.

At first impression, this fearless existence might sound pretty great – like having some sort of super-power. But like pain, although it’s unpleasant, fear is actually pretty useful. Or at least, it used to be, back when life was simpler and all we had to be scared about was whether we might get eaten by a lion on the way to the prehistoric supermarket.

Although we often tend to condense it down to the simplified chemical cocktail of the ‘fight-or-flight’ response – fear in the modern day is a complex thing. In terms of the actual danger present and the adrenaline-fuelled response it causes us to feel, it’s reasonable to say that the experience of another person approaching you in a dark alleyway is probably the one of closest equivalents to that of being stalked by a lion, which our ancestors would have experienced back in the day. But for many of us, the things that we encounter on a more regular basis that actually cause this kind of response are much more abstract, and don’t contain a threat that might cause you any bodily harm. Take public speaking for example, or job interviews, or exams, or turning up at a party and realising that you know absolutely no one – these are much subtler than the relatively straightforward experience of a lion ripping your arm off. In these contexts, running away or fighting doesn’t equal ‘survival’ (and they probably won’t get you the job), so an interesting question is: why do our brains bother generating this unnecessary fear? This is something we still don’t know the answer to, but studying conditions such as Post-Traumatic Stress Disorder may lead us to better understand ‘excessive’ or ‘inappropriate’ fear in the future.

And that’s all without even getting onto the more existential fears that we humans are pretty terrified of: of being alone, of failure, of getting old and dying, of the uncertain future, of never making your mark on the world, and other such rays of sunshine. For most of us, if we’re healthy, we don’t have a constant flight-or-fight response going for these things – there’s obviously something very different going on in these kinds of fears which ‘lurk’ in the background of day-to-day life.

halloween-blog2
The classic fight-or-flight response is a very integral part of fear, and is relatively easy to study and measure in an experimental context compared to other aspects, but it’s not all there is to it. It would appear that fear is a complicated and uncertain business. But from what we do know, if you’re stuck for a last-minute Halloween costume this evening why not opt for something that’s witty, bizarre and which everyone will absolutely ‘get’ – no questions asked: why not go as a brain (‘I’m an amygdala…duh?’ – as the classic Mean Girls quote we all know and love goes, right?)
Or, I guess, a shrub.

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“But how did I get here?”: The Rabbit Hole of Human Opinions

alice2
Opinions: everyone’s got ‘em. This could not have been made more apparent after the recent result of the EU referendum in the UK. However, this is not intended to be a politically-charged post, nor a canvas for my own personal opinion. Because if recent events have made anything clear it’s that opinions are like the brains they’re made in: downright messy.

Divisive appears to be the most fitting word to describe the whole thing – and not just literally in terms of the outcome, which will now see the UK leave the EU. As the referendum campaigns unfolded, I couldn’t help being struck by how utterly chaotic and misleading the whole process seemed – even for politics. Political parties were split and unable to form their own cohesive standing points on the matter. In the aftermath of the result, I have watched people I know to be rational, intelligent humans, lose it in social media comment fights with people they don’t even know. So, in order to restore an ounce of normality to the world, I’ve decided to address this the only way I know best – talking about brains – and hope that normal service will resume soon…

So what has this got to do with the brain?
In a nutshell, the whole biological point of having a brain is that it allows you to receive information about all the stuff that’s going on around you, make some kind of sense out of it, and then translate this into appropriate actions and decisions which you then carry out. And, as brains go, humans do this pretty darn successfully: our domination of an entire planet being a case-in-point. But sometimes your brain is irrational in ways we’re blissfully unaware of as we bumble through life trying to make the right decisions in the face of quandaries such as: ‘how many consecutive episodes of New Girl is ‘too many’?’, ‘is this cheese really that far past edible?’, and ‘should our nation leave an international  union it’s belonged to for decades?’ Consciously, you might be the most rational and open-minded of people but unconsciously, your brain is still capable of implicit bias on the sly without you noticing, especially in response to things other humans say and do.

‘No, I’M the most opinionated!’
We all know at least one person who will loudly proclaim that they ‘don’t care what other people think’ when it comes to their life decisions. And this may well be the case…as far as they’re aware. However, as social animals, the human brain has evolved so that actually we are very much influenced by what other people think of us – to the extent that patterns of brain activity seen following social rejection are incredibly similar to those associated with physical pain. Our desire to be accepted by social groups has both good and bad sides, but mostly makes for a lot of weird and baffling things happening when a bunch of like-minded brains get together. One well-documented example of this is group polarisation. If you stick a group of people together with the same opinion on something (for example: ‘you should always put the milk in first*‘), rather than conform to the average view of the group (‘tea’s quite nice if you put the milk in first’), individuals’ viewpoints will actually become more extreme (‘the milk should go in first, and anyone who disagrees should be slowly and painfully drowned in a scalding vat of their own incorrectly-made tea, the heathens!’)

#relatable
We identify most strongly with groups of people who are like us, and perceive those who are different, or outside the group, as a threat to its integrity. In keeping with this, there are lots of subtle ways that our brains can generate bias in our perceptions of people different to us. This might be people with different tea-drinking habits to you, or, more scarily, people of a different race to you. Implicit racial bias has been shown in several different types of study. For example, when a group of white American subjects were asked to pin-point when the expression in a gradually changing series of face images changed from ‘hostile’ to ‘happy’. It took them much longer to do this when the faces were black than when they were white, suggesting the possibility that anger was perceived in faces of a different race for a longer proportion of the ‘hostile-to-happy’ spectrum that subjects were shown. I’m sure you can see how this is not particularly great news.

Confidence: being flamboyantly wrong
We generally perceive people who are confident as being more convincing. This has been widely shown but particularly in studies mimicking witness testimonies in courtroom: witnesses who come across as confident when they speak are deemed to be more credible than those who appear hesitant. However, confidence does not always mean someone’s right (I know?!). In fact it’s been repeatedly shown that those who perform worse in a test or task tend to believe they’ve done better than they actually have: not only have they done badly, but they lack the ability to evaluate and recognise this. The reverse is seen in people who’ve done well in a task: they generally assume they’ve done worse than they have. This phenomenon is called the Dunning-Kruger effect. So there you have it, people who are wrong – they might be telling outright lies, or spouting incorrect statistics – can dazzle you with their confidence, all the while thinking that they’re doing a tip-top job of whatever it is they’re doing. A memory task in a lab. Trying to convince a nation how to vote in a referendum. Potayto-potahto.

I got the itch to write this post, not so much in reaction to the result of the referendum, but rather as some food for thought in reaction to the bewildering lack of rationality that, for me, seemed to characterise the whole event. I’ve had conversations with people voting both ways, and been amazed that in several cases they’ve been unable to explain to me in what I consider to be meaningful words, the evidence or even the thought processes which lead them to their decision. And so I hope this post serves to highlight something which I think, given recent political events (and future ones, what with the US Presidential Election coming up), we as humans would perhaps all do well to remember: your brain is biased and irrational. Sometimes without you even realising, and especially in the context of groups of people, and especially in the context of groups of people who are different to you. So when it comes to making decisions, no matter what your opinion on a matter is, we owe it to ourselves to first ask: ‘but why do I think that?’
Because opinions can be quite a rabbit hole, with your brain subtly and implicitly pulling the strings. Sometimes, it pays to look for this before you leap.

*I don’t drink tea. Calm down and go and put the kettle on for the mob you’ve just assembled. (Or, on second thoughts, might be safer if you don’t.)

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