Neuroscience news block: Best of 2017

Ho-ho-ho! Look what Santa brought us here! This awesome neuroscience blog has awoken from the master thesis-induced hibernation and is ready to bring the wonder of neuroscientific discovery to the masses again! What a great present! (I know, you might have asked for a new laptop or a promotion. Talk it out with Santa, I’m doing what I can here).

As this year (thankfully) nears its end I sampled some of the most interesting neuroscience studies of 2017 to make you go whoa. Buckle up kiddos, this one is gonna be quite a ride!

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  1. Let’s get the really important stuff out of the way first: this year I survived finished my master thesis and got a neuroscience degree! Without a doubt the most exciting piece of news far and wide.
I am now officially allowed to talk about neuroscience.

I am now officially allowed to talk about neuroscience.

2. The second most exciting piece of news (for all the psychedelics enthusiasts at least) is yet another study by London researchers which solidified the potential benefits of psilocybin (the active compound of magic mushrooms) for people with depression1. The scientists found that a single dose of psilocybin leads to an effect they described as a “reset” of the brain. All of the patients with treatment-resistant depression felt much better one week after the treatment and 47% reported feeling much less depressed even 5 weeks after.

One day after the trip scientists observed substantial changes in the functional connectivity of the brain -- that is, in the way brain regions talk to each other. For example, the regions shown to be communicating too much in depressed patients (fueling up rumination as they do) were much less talkative with each other after the trip. The extent of these changes also helped to predict whether a patient would still be less depressed 5 weeks after the experiment. Moreover, there was a decreased blood flow in amygdala, our fear center, which went along with reduced depressive symptoms. Can’t have depression if the fear center is starved!

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Interestingly, the after-the-trip changes were very different from during-the-trip changes (read up here and here if you're interested in what's going on in your brain during the trip). This led to the assumption that psilocybin first causes an acute disintegration during the trip (networks fall apart, “I just talked to the Universe, man!!” etc.) followed by a post-trip re-integration where the parts come back together but in a better, less dysfunctional way (like maybe the thought pattern “My boss did not answer because HE HATES ME!!” is substituted by something… more reasonable), hence the “reset” term. Of course, there is still a lot of room for improvement but it seems that step by step we are nearing a new promising treatment for even the most stubborn of depressions.

3. Maybe even more exciting is that researchers have created a non-invasive brain-computer-interface (BCI) that allows communication with completely locked-in patients who have zero muscular control2. If I was out for sensationalist headlines I would even say… there was some mind-reading involved.

Although there has been some progress allowing locked-in patients to communicate with the outside world3,4, a meta study5 revealed that none of the options is optimal (for one, a good chunk of them is directed to people whose eye muscles were intact and are not appropriate for people who can’t move their eyes and blink). This is where the present study comes in.

By measuring changes in the electrical activity and blood oxygen level in the brains of 4 completely paralysed patients researchers were able to establish a binary “yes/no” communication with them. First, patients were repeatedly asked some basic questions and instructed to think “yes” or “no” as a response. An algorithm was then trained to differentiate between patterns of blood flow and electrical activity for both of these responses. Soon it was able to accurately recognise the patient’s thought answer in 70% of cases. Interestingly, all 4 patients thought a “yes” when asked whether they are happy. We should be happy too as this study is paving the way to establish -- at first a rudimentary -- communication with people who are harder to reach (as compared to patients who still can move the eyes).

Here's a demonstration of how it works.

4. Throw out your anti-age face cream! Scientists have managed to slow down aging by tweaking the brain! Okay, it is really easy to get carried away with sensationalism… Sorry.

Indeed, researchers have discovered that stem cells (a type of cell that can develop itself into many different cell types) in hypothalamus (brain region concerned with many bodily functions) regulate ageing6.
The researchers noticed that these stem cells start to vanish from mice hypothalamus around 11 month of age (corresponding to around 40-50 in human years) and completely disappear by 22 months. Such signs of ageing like memory loss went along with the amount of the lost stem cells.

The scientists then proceeded to remove or add stem cells to this region in order to speed up or slow down the ageing. Turned out that mice in whom the majority of stem cells was removed displayed premature ageing, got retired, complained about youngsters all day long and died significantly earlier. However, when stem cells were added mice showed better memory performance, did power walking, played bingo and lived 200 days longer compared to an average mouse. It has to be noted that the implantation only worked if the new stem cells were made to be resistant to inflammation as the age-related inflammation seems to interfere with the hard-working stem cells preventing their anti-age effect.
There is still a long way to go before you can really throw away your anti-aging cream... but we are sure on our way there.

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5. What do space travels hold out for us? Aliens? Life on Mars? Planting potatoes on Mars? Before we can know for sure we need to find out what a prolonged stay in space will do to our brain. A NASA-funded study investigated just that and found that after being on the ISS for a while the brain gets -- quite literally -- spaced out.

Firstly, with no gravity to pull it down, the brain floats upwards in the skull. Unfortunately there was no second post-space scan to see whether it eventually returns to the normal position or whether it stays upwards, reaching for the stars. Secondly, a fold on top of the brain separating motor areas from the sensory ones (called the central sulcus) got compressed and became narrower. On a long mission this might lead to changes in the brain function. In some cases, the upward brain shift was also thought to be responsible for the increased pressure on the optic nerve leading to some extent of vision damage (which is often reported by astronauts). Last but not least, the vessels carrying the cerebrospinal fluid (which cushions our brain and helps with clearing out waste and toxins) got narrower too, whereas the CSF-filled areas in the brain got larger. As the disturbances in the CSF flow are linked to a lot of diseases such as Alzheimer’s it would be handy to find out whether they are cause or effect of these diseases before sending people out on years-long space missions.

More studies need to be done before we can know for sure what the the significance of these changes is or how the brain reacts to a reduced gravity environment (think Mars), but once we’re through we’re ready to boldly go where no man has gone before!

If I see a way to squeeze in some Bowie, I squeeze in some Bowie.

6. Normally, patients who have been in a vegetative state for more than a year are not very likely to regain consciousness which makes the case of a 35-year old French man even more stunning. After spending 15 years in a coma the patient partly recovered his consciousness after being subjected to electrical brain stimulation7.

Vagus nerve played the central role in this miraculous recovery so let’s get to know this guy a little better. Vagus nerve is a complex nerve running from your brain to several body areas and controlling unconscious body procedures such as heart rate. Moreover it is directly or indirectly connected to several brain areas including thalamus, amygdala and hippocampus all of which play important roles in conscious awareness. It also connects to locus coeruleus which plays a role in alertness and attention.

So what the researchers did was to zap this nerve every day for six months. Soon after the beginning of the treatment he started opening his eyes more often, while after one month he was able to track objects with his eyes and turn his head when requested. Electrical activity in his brain reflected these changes -- brain waves which have been absent before were now observed. Basically a shift from no consciousness to minimal consciousness occured, all thanks to the stimulation of one nerve. Despite apparent (albeit minimal) success it is a very long way before we can understand how and why exactly this worked (question about the nature of consciousness, everybody) and generalize it for other patients locked in the vegetative state. But hey, first steps and all!

Left: PET scans (showing glucose metabolism and hence brain activity) before the vagus nerve stimulation. Right: PET scans after the stimulation showing increased brain activity in in the right parieto-occipital cortex and thalamus (all areas hypothesised to have something to do with consciousness). Corazzol, Lio et al., Current Biology (2017)

Left: PET scans (showing glucose metabolism and hence brain activity) before the vagus nerve stimulation. Right: PET scans after the stimulation showing increased brain activity in in the right parieto-occipital cortex and thalamus (all areas hypothesised to have something to do with consciousness). Corazzol, Lio et al., Current Biology (2017)

Stay tuned for a post on the neuroscience of sleep coming up early next year!