December 2013 – The Brain Bank North West

Flashes of brilliance in the brain – the best neuroscience images of 2013

April 30, 2014December 23, 2013 by The Brain Bank North West

Pretty pictures and popular neuroscience go hand-in-hand. People love to see the contours of their brain on an MRI and journalists are drawn to a brain flashing away with activity. There have been some fantastic images from neuroscience in 2013. Here are my favourites, one for each month starting way back in January 2013.

Disclaimer – We own no rights to any of the images on this page. All images are credited to the original authors and copyright holders. The MRC’s Biomedical Picture of the Day has been used as inspiration for some of the images.

January – New eyes for blindness

Blindness is a major challenge to the neuroscience field. Untreatable blindness is often caused by a degeneration of the light-sensitive cells of the retina. Here, researchers from University College London, UK have injected new photoreceptor cells into the retina of mice with retinal degeneration restoring normal responses to light!

Host retina cells are shown in blue, injected new photoreceptive cells are shown in green. The top left is a healthy mouse. The next three images show three different types of genetic blindness models in mice – all show integration of the injected cells. From Barber et al. PNAS 110(1): 354-359

February – Pathfinding connections in the brain

This year there has been a burst of activity in the ‘connectomics’ field. Mapping the connections of the brain is the next big challenge of neuroscience and the main topic of the Human Brain Project in Europe and the BRAIN initiative in the US.

Here, researchers from the École Normale Supérieure in Paris, France looked at how neurons find their way from the thalamus in the middle of the brain to the outermost folds of the cortex.

These figures show neurons in green making their way from the thalamus (Th) to the cortex (NCx). From: Deck et al. Neuron 77: 472-484.

March – Whole brain activity

http://www.youtube.com/watch?v=KE9mVEimQVU

Seemingly a burning campfire, this is actually a brain flashing with activity. In one of the most impressive images of neuroscience in 2013, researchers from Howard Hughes Medical Institute’s Janelia Farm campus in the US used calcium imaging (see July) to view the activity of a whole brain.

The brain of a zebrafish larvae – imaged by light-sheet microscopy. From Ahrens et al. Nature Methods 10: 413-420.

One of the biggest challenges of neuroscience is working out how everything links up together. The most accurate measurements we currently have can only take into account a handful of cells at once. The brilliance of this technique, utilising see-through zebrafish larvae, is that they were able to image more than 80% of the neurons of the brain at once. This can tell you how large populations of cells interact, allowing different regions to work together.

For more info see this article by Mo Costandi in the Guardian.

April – See-through brains

Another amazing technical feat designed to view how the brain links together, in April we were brought CLARITY. By dissolving the opaque fat of a brain whilst keeping the structure intact, researchers led by Karl Deisseroth at Stanford University, California were able to image a whole mouse brain.

The hippocampus of a mouse, visualised with CLARITY. Excitatory cells are green, inhibitory cells are red, and support cells called astrocytes are blue. From Chung et al. Nature 497: 332-337.

The images from this technique are truly breath-taking. Using this technology, researchers could look in detail at the structure of the brain, giving valuable information of the wiring of different regions. They even imaged part of a post-mortem human brain from an autistic patient, finding evidence of structural defects normally associated with Down’s syndrome.

For more info, see this article in New Scientist.

May – Brainbow 3.0

‘Brainbow’ is a transgenic system designed to label different types of cells in many different colours. Prime material for pretty pictures. Take a look at these:

Multicoloured neurons. b shows the hippocampus, c and d show the cortex. From: Cai et al. Nature Methods 10: 540-547.

June – Controlling a helicopter with your mind

In June, researchers from the University of Minnesota, USA showed that one could fly a helicopter with their mind! Watch below as the subject guides a helicopter using an EEG skullcap.

July – Better calcium sensors

More calcium imaging now. Calcium imaging works by engineering chemicals that will fluoresce when they encounter calcium. When nerve cells are active, millions of calcium ions flow into the cell at once, therefore a flash of fluorescent light can be seen. Here, researchers from Howard Hughes Medical Institute’s Janelia Farm campus in the US have been working on better, more sensitive calcium sensors. Using these you can colour code neurons based on what they respond to.

Caption: Neurons colour-coded by their response properties. From Chen et al. Nature 499: 295-300. — Neurons colour-coded by their response properties. From Chen et al. Nature 499: 295-300.

They were also able to record a video of the electrical activity in dendritic spines, the tiny arborisations of nerve cells – see here.

August – Using electron microscopy to connect the brain

Drosophila are wonderful little flies with nervous systems simple enough to get your head around, but complicated enough to be applicable to our own.

Caption: An electron micrograph, colour coded for each individual neuron. From: Takemura et al. Nature 500: 175-181. — An electron micrograph, colour coded for each individual neuron. From: Takemura et al. Nature 500: 175-181.

Here, researchers from Janelia Farm (again!) have performed electron microscopy on drosophila brains to connect up neurons across multiple sections. An algorithm colour codes them to line up the same neuron in different sections in what looks like a work by Picasso.

September – Astrocytes to the rescue

Astrocytes are support cells in the brain which become highly active following brain injury. Here, researchers from Instituto Cajal, CSIC in Madrid, Spain were interested in the different characteristics astrocytes take on when a brain is injured. The injury site can be seen as a dark sphere. Astrocytes with different characteristics have been stained in different colours. For example, the turquoise-coloured astrocytes can be seen forming a protective net around the injury site.

The injury site (dark sphere) can be seen surrounded by multi-coloured astrocytes. From: Martín-López et al. PLoS ONE 8(9) .

October – Preserved human skulls

Not strictly neuroscience but these images need to be included. Published in October 2013, The New Cruelty (commissioned by True Entertainment), photographed a series of preserved human skulls.

A preserved human skull. From the New Cruelty exhibition, commissioned by True Entertainment.

November – Brain Computing

Part of the vision of the Human Brain Project and the BRAIN initiative is to marry anatomy of the brain with computer models to try to produce a working computer model of the brain. This image represents BrainCAT, a software designed to integrate information from different types of brain scan to gain added information about the functionality of the brain.

This image shows BrainCAT linking functional MRI data with connectivity data (diffusion tensor imaging). From: Marques et al. Front. Hum. Neurosci. 7: 794 — This image shows BrainCAT linking functional MRI data (blue and turquoise shapes) with connectivity data (diffusion tensor imaging – green lines). From: Marques et al. Front. Hum. Neurosci. 7: 794.

December – Men Are from Mars, Women Are from Venus.

The last month of the year gave us preposterous headlines of ‘proof’ that “Men and women’s brains are ‘wired differently’”. This finally proved why women are from Venus and men are from Mars; why men ‘are better at map reading’ and women are more ‘emotionally intelligent’…. These exaggerated headlines have been kept in check recently on this blog but there’s no denying that the research paper did show some lovely images of male and female brain connections.

The top shows the most interconnected male regions, the bottom shows the most interconnected female regions. From: Ingalhalikar et al. PNAS (online publication before print).

So that’s it. 2013 was a year of flashing brains, dodgy connections and overegged hype. Let’s hope there’s even more to come in 2014.

Post by Oliver Freeman @ojfreeman

Battle of the brain’s sex differences…or not really?

December 18, 2013December 17, 2013 by The Brain Bank North West

Why some people are surprised at the very idea of there being differences between male and female brains I don’t understand. But, what really confuses me is when journalists misinterpret research findings and overextrapolate speculative comments to fit cliched gender stereotypes.

65464_web — “Brain networks show increased connectivity from front to back and within one hemisphere in males (upper) and left to right in females (lower).”
Credit: Ragini Verma, Ph.D., Proceedings of National Academy of Sciences, from press release.

Whenever I ask my (less sciencey) friends what they’d like to read on The Brain Bank, there is a perennially raised topic. At least one, usually single, hopeful will ask desperately for a guide on how men and women’s brains differ – and why they might work in different ways, scientifically speaking. Efforts to crack the mental codes of the opposite sex started as far back as Aristotle, who claimed that women were “more mischievous, … more easily moved to tears[,] more apt to scold and to strike[,] … more void of shame or self-respect,…of more retentive memory” (History of Animals).

White matter tracts, as imaged using diffusion tensor imaging. Author: Xavier Gigandet et al., source here.

Earlier this month, a research paper from the University of Pennsylvania used a fancy imaging technique called diffusion tensor imaging (DTI) to solve the mystery behind the different ways guys and gals think. DTI basically gives you a picture of where the white matter tracts – the wiring between different brain areas – lie between various processing parts of the brain.

The technique works by looking at how water travels within the brain: water ‘prefers’ moving along bundles of fibres, such as white matter tracts. In this way, DTI examines the strength of ‘connectivity’ between various parts of the brain.

Researchers, led by Prof Ragini Verma, scanned the brains of 949 youths aged 8-22. They found that, in general, the connecting pathways within each half of the brain were stronger in guys, but that in girls, the wiring between the two halves was stronger. In other words, connectivity in girls tended to be more ‘left-right’, whereas in boys, ‘front-back’ connectivity was stronger.

The researchers also reported that the girls performed better on tests involving attention; word and face memory; and social cognition, whereas boys fared better on spatial processing and sensorimotor speed tasks.

This paper and its associated press release rallied some…OK, a lot, of interest from the press. But then something strange happened. Something was lost in translation between the original paper and the resulting newspapers reports, claiming that ‘hardwired’ differences between men and women’s brains might explain ‘why men are better at map reading’ and women are more ‘emotionally intelligent’…

OH dear…

…Then there was a knee-jerk reaction against the potentially neurosexist connotations of this ‘kind of science’, and not just because the research was published in PNAS (hehe). In my opinion, if a conclusion is based on valid and reliable science, you shouldn’t really argue unless you have definitely read the research. If, on the other hand, the offending ‘conclusions’ are the result of a bizarre ‘Chinese Whispers’ scenario where no one has actually read the original research, then no, it’s probably not worth listening – but then, mistranslation isn’t based on science anyway…I digress.

While we all know that there are some obvious – and other more subtle – distinctions between men and women. This research article doesn’t actually claim to explain anything besides the physical connections between different parts of the brain. Just to clarify, here are some of the problems with treating this particular research paper as the Holy Grail of sex differences:-

1. There’s no saying whether there’s a big difference or not. The authors present (undeniably) a very striking diagram, with the statistically significant bits indicated in gender-relevant colours. However, just because a difference is statistically significant, doesn’t mean the effect of being male, or female is a big deal. In fact, as the study uses such a large sample (949 youths), even very small differences between male and female brains may prove significant.

2. Less wiring doesn’t necessarily mean lower ability. The authors don’t actually indicate anywhere in the paper that the ‘wiring’ is associated with men and women’s differing abilities on the tests – though Prof Verma has been quoted speculating on the possibility. Instead, the authors have pointed out the brain’s physical differences and then separately comment on behavioural differences without saying whether the two correlate.

If the hypothesis is that men or women with mega-strong connectivity left-to-right, or front-back are respectively better at, say, language, or football, you could easily find that out with a bunch of correlations. Not that correlation would imply causation anyway. In fact, the strengthening or weakening of physical connections could even suggest that women and men’s brains change to compensate for innate differences!

3. Size/proportions might matter. It’s pretty well-known that men have larger brains than women – the situation is pretty complicated though, as women reportedly have more grey matter, less white matter and a thicker cortex than men. However – please correct me if I’m wrong – the authors don’t correct for brain sizes (either front-back, left-right, total volume or any other measure), which could be very important. Especially considering the people being imaged are aged between 8 and 22, when brains grow a lot anyway. Not to mention that girls and boys grow at different rates too. Oh well.

Social media word clouds for females (top) and males (bottom). Size = strength of the correlation; color = relative frequency of usage. Underscores (_) connect words in phrases. Words and phrases in center; topics surround. Author: H. Andrew Schwartz et al.; Source. Apologies for the bad language!

4. There are many more potential mechanisms than meets the eye. Yes, it’s very possible that exposure to sex hormones could change the brain’s connectivity. But, there’s a whole host of other possible influences on a child going through puberty that can’t be ruled out, because the brain is notoriously/amazingly plastic. Environmental influences, influences that can’t ever be controlled for, such as parents, peers, teachers and the media – could just as easily alter the physical structures of the brain, or the brain’s abilities. In fact, hearing in the news that ‘men are better at map reading’ because it’s ‘hardwired’ in their brains is conceivably rather likely to make guys feel a bit more confident navigating, while discouraging women from taking that responsibility instead.

This piece of research is not the first and certainly won’t be the last to be accidentally misinterpreted or overhyped. Research into the differences between men and women will continue to fascinate us because, for whatever reasons – social, biological or otherwise – people of different sexes tend to look, sound and act differently. More seriously (and the authors of the paper explain the motivation of their research), sex differences are linked to brain disorders like autism and depression, so the differences between ‘Martians’ and ‘Venetians’ should be properly understood, and carefully reported.

For further examination of this topic, here’s another blog article and a BuzzFeed piece with a few more reasons why it should all be taken with a pinch of salt.

Post by Natasha Bray

The confusing science behind weight loss

December 2, 2013 by The Brain Bank North West

It’s getting to that time of year when it becomes socially acceptable to stuff yourself full of the fattiest foods imaginable and then do nothing for 48 hours. You may be one of those people who is planning on upping your exercise regime to compensate for the increased calories consumed over the holidays. Unfortunately, I have some bad news for you: It’s probably not going to work.

Exercise and weight loss: is it a myth?

It’s long been burned into our brains that doing exercise is a good way for us to lose weight. This link was first noted by the scientist Jean Mayer in the 1950s, who observed that girls who did less physical activity tended to be obese. Since then, we’ve been regularly targeted with gym adverts and equipment aimed to get us moving and help us lose weight. You “burn off” calories when you exercise and so don’t gain weight, right?

However, in recent years the message has become increasingly confusing. There is an increasing level of evidence (examples here, here and here) that suggests that exercise alone is not an efficient way to lose weight. According to the Mayo Clinic, you’d have to remove 500 calories every day for a week to lose 1 pound in weight. To put that in context, you’d have to do about an hour of high-impact aerobics every day for a week to burn off 100 grams worth of cookies. Not eating the cookies in the first place would be a far more effective way of losing weight.

It is important to remember that exercise is important for maintaining your weight. Therefore if you’re trying to lose weight and keep it off, experts believe that the best thing to do is to gradually reduce the amount of calories you eat but also to do regular exercise. People who crash diet or severely restrict the amount of calories they eat have a tendency to regain weight quickly once the diet is over. Crash dieting also leads to other health problems and can even reduce your ability to lose weight in the long term.

Another message which seems to be getting lost is that there is a big difference between “weight” and “health”. Exercising will keep your body and mind healthy. Some scientists believe that being obese does not necessarily mean that you are unhealthy in the same way that being thin does not automatically make you fit. It would be better if people aimed to be “healthy” rather than “thin” and exercise is essential if you want to be healthy.

Sugar, sugar

Even more confusing than the exercise/weight loss conundrum is the recent idea that fatty foods such as butter and red meat may not be as bad as we thought. Some scientists, such as Dr Robert Lustig, believe that it is sugar, not fat, which is causing the current obesity trend. Dr Lustig attributes the toxicity and addictive nature of sugar (specifically fructose) to the rise in obesity levels. The increase in sugary drink consumption has also been attributed to the skyrocketing levels of type 2 diabetes.

This advice has been taken on board by some governments. In the UK, the official line from the NHS is still that obesity is caused by “eating too much and moving too little”. However, the Swedish government has implemented a dogma of eating a high-fat, low-carb diet. This is essentially a less extreme version of the Atkins diet in that you limit the amount of carbohydrates you eat (including sugar and “starchy” foods such as potatoes, pasta and wheat bread) but can eat as much butter, cream and bacon as your heart desires. This diet could also explain the French Paradox; that is, the observation that people in France are relatively healthy despite a high consumption of fatty food.

When is a healthy food not healthy?

When it’s a smoothie. If you take into account the idea that sugar, not fat, is the cause of the country’s dietary health crisis, then smoothies and fruit juices are unfortunately categorised as “a bad thing”. It seems hard to stomach after being told for so long that fruit is a “healthy” alternative but fruit is packed full of sugar. More sugar is released from fruit when it is in liquid form. You’ll be relieved (or horrified, depending on your outlook) to hear that vegetables are still classed as “healthy” as they contain less sugar than fruit.

There are also questions about “sugar-free” drinks, which contain artificial sweeteners such as aspartame. Whilst the alleged link between aspartame and cancer is so far unclear, there are people who think now that aspartame and other artificial sweeteners may cause weight gain.

Who do you call?

Part of the confusion that stems from this crisis is the vast array of information coming at us from all sides. Some scientists say one thing (“fat is bad”), other scientists oppose them (“sugar is bad. Exercise is good but not for weight loss”). The government takes the advice of one side of scientists (currently the “fat is bad” side) and informs us about lifestyle choices according to the advice they receive.

The “professional” dietary industry is confusing. There are differences between a dietician and a nutritionist. A dietician is accredited and is a protected title, a nutritionist isn’t. This means anyone can refer to themselves as a nutritionist, even if they have no background or knowledge on the subject. So the information that is being spread by some so-called “expert nutritionists” could be entirely false.

What’s even more confusing is even if you do consult a dietician, the information is changing all the time. Fat is bad, fat is good, avoid sugar, exercise a lot, exercise moderately. All of these have been given as scientific-based advice in recent times.

Evil, bad scientists?!

Before you grab your torch and pitchforks and hunt out all the scientists for releasing this confusing information into the world, please remember that research into diet is very complex. For example, is it that inactive people are fat or that fat people are inactive? Whilst certain elements may cause obesity in laboratory animals, humans are a different kettle of fish. People have a tendency to lie in surveys about our eating habits, and weight can fluctuate a lot. This means that accurately researching the causes of obesity and related illnesses is extremely complex.

The problem is not so much to do with the scientists, who are doing the best they can, but the way that the market is controlled. The advice from the government doesn’t really take into account more recent data. Additionally, people who sell smoothies or own gyms will keep marketing their product as “good for losing weight”. We’re targeted with a lot more adverts for gyms and food than we are with the latest scientific information. Scientists accept that data and findings are changeable and accurate data takes many years and many, many people. Advertisers and businesses are not so patient.

This is all making me want to curl up into a confused little ball. And comfort-eat a tonne of chocolate. What should I do?

I’m sorry to say I can’t help you. I am not a dietician (or even a nutritionist). My inexpert advice, (coming from nothing but reading a few articles and journal entries on weight loss) is that we should all aim to be “healthy” rather than “thin”. Healthy means different things to different people. Do what you need to do to feel healthy. This could include exercising regularly, trying to cut down on your sugar intake and/or avoiding fast food, which is usually packed full of sugar and salt.

Comfort-eating the chocolate may not be as bad as you think (maybe eat less than a tonne though). There have been papers published which find that eating chocolate (fat, sugar and all) can lead to weight loss, in both children and adults. Chocolate consumption has also been linked to lower incidences of cardiovascular disease and stroke.

So what do we know, really, about diet, obesity, health and exercise? Not an awful lot, I’m afraid.

Post By: Louise Walker