Neuroscience news block: Robo-suit and virtual reality help reverse paralysis, reprogramming the mouse brain and what to eat to stay (mentally) fit.

As usual, recent discoveries from the field of neuroscience continue to shed light on our mysterious lump of fat and make it clear that we are already living in the future.

1. The most joyful piece of news is certainly the study showing how the condition of paralysed patients improved after a year of brain-machine interface training. Prior to the study the participants were completely immobilised and numb below the waist due to a spinal cord injury. Surpassing the researchers’ wildest hopes the rehabilitation really kicked in -- the patients partly regained sensation and movement control in their legs.
This was done by a technology that sounds like it has been taken from an Asimov novel. First, the patients learnt to control the walking of an avatar while wearing a virtual reality headset. So they would imagine raising the right leg, the algorithm would translate the brain waves arising from the motor cortex into movement commands which then are sent to the avatar. After this the patients upgraded to standing on a treadmill with their body weight supported. At this stage, their brain signals controlled a robotic walking system which moved their legs on this treadmill. The last training step was to make an exoskeleton suit walk around, again powered by the mind control.

An exoskeleton gifting paralysed people with the ability to walk. 

An exoskeleton gifting paralysed people with the ability to walk. 

In order to give the people some kind of a feedback on how it would feel to move their feet researchers put a small vibrating patch on their triceps. When the robotic foot touched the ground it would vibrate in a specific way depending on whether it was, say, grass or sand. 
After 12 months of this sci-fi sounding training all eight participants showed significant improvements: They started to feel pain and vibration in some parts of their legs, gained some control over their bladders and bowel movements and, probably most importantly, they could voluntarily control their leg muscles again -- even if to a relatively small degree. It seems that the nerves rendered dysfunctional by the injury could be gradually brought back to life! And it gets better and better as the team is preparing a publication on the results of the following 18-month training. Moreover, the brain, malleable as it is, seemed to reorganise itself -- after the training scientists saw some activity in the patients’ brain which is normally characteristic for healthy people preparing to move their limbs.

These news deserve a celebration! Image by TomaTheSpook.

These news deserve a celebration! Image by TomaTheSpook.

2. “What fires together, wires together” is one of the sentences every neuroscience undergrad has heard even more often than “It’s not you, it’s me” or “Here’s your coffee”. What it means is essentially that neurons that are active at the same time (like, for example, if they are encoding a certain memory or association) become strongly connected and form a network. Very simplified, if you repeatedly get a slight electric shock while listening to Justin Bieber the neurons registering the pain are active simultaneously with the neurons perceiving the sounds. The connections between these nerve cells grow stronger and after a couple of times just hearing the music will activate the whole neuronal network and make you cringe and tense up (which is a right reaction to Justin Bieber anyways). This phenomenon, known as Hebbian rule, has really helped us with understanding memory and learning.
Researchers at Columbia University had it in mind when they took a mouse and artificially created one of such networks in its visual cortex. What was revolutionary about this is that normally such a neuronal ensemble would arise when you (or a mouse) experience something. This time the network did not base on any real events but was just “written in” in the mice’s brain and thus completely unfamiliar to to the fluffy science martyrs. You could say, the scientists changed the mouse’s wiring. To do this they used optogenetics: Specific neurons were made light-sensitive and could subsequently be manipulated by a very precise laser. The scientists repeatedly stimulated a small group of light-responsive neurons forcing them to bond with each other and to create a network. After a while they saw that the activation of just one cell triggered the whole ensemble to lighten up. So not only did they implant an artificially created neuronal network into the mouse brain, they even showed -- for the first time -- how the pattern completion functions. Smell a homemade cake your mom used to make and watch the childhood memories unwrap in front of you.
Moreover, researchers believe that they might have inserted an image totally unknown to the mice when they put this new network into their brains. The key word is “might” -- they are not certain whether the mice really saw something yet unbeknown to them, be it fresh Gouda or just a pattern of dots; to investigate this, a new behavioural study is being prepared. Stuff like this has already been done, by the way: in 2012 Steve Ramirez and Xu Liu inserted a false memory into the mouse's brain making it remember a traumatic event that never happened.
This whole thing has interesting implications for the clinical settings: If we can potentially correct the patterns of neuronal activity and put in new ones does it mean possible future cures for diseases like epilepsy or depression?

Will we sometime be able to alter neuronal firing however we please? Image by TomaTheSpook.

Will we sometime be able to alter neuronal firing however we please? Image by TomaTheSpook.

3. If you are still waiting for that Monday to finally start eating healthy than I have something for you. Remember Popeye and his spinach? The thing I’m gonna talk about is not such a quick fix, yet it seems to be equally powerful. Two recently published studies praise Mediterranean diet as a means to slow down cognitive decline, improve your memory and attention and reduce your risk of Alzheimer’s. And this diet is hella healthy AND yummy -- it includes a lot of goodies such as leafy greens, fruits, fish, nuts, whole grains and olive oil while cutting down on red meat and dairy. A review analysing all published studies on that topic from the previous 15 years that the positive effects persisted independent from country and age, meaning you can start working on having a more pleasant senior years already now.
These positive effects have a lot of possible reasons: Elements found in nuts and olive oil may help keeping the cell membranes strong and prevent neurodegeneration, cardiovascular benefits helps with the blood supply to the brain and, finally, this diet can help to reduce inflammatory processes in the body (and we know that neuroinflammation is not good for brain at all).
The second study took a more detailed look and found that people with mild memory problems who stick to this diet (and exercise) are less likely to have a build-up of beta-amyloid and tau proteins in their brains. These guys are one of the main causes of Alzheimer’s as they form plaques which disturb communication between cells, cause inflammation and damage the neurons. So stock up on the veggies and the extra virgin olive oil -- your grandchildren will thank you later (or your cat if you’re child-free).

You can always rely on these guys to protect you. Image by tomaTheSpook.

You can always rely on these guys to protect you. Image by tomaTheSpook.

Sources:
1. http://www.nature.com/articles/srep30383
2. http://science.sciencemag.org/content/353/6300/691
3. http://journal.frontiersin.org/article/10.3389/fnut.2016.00022/full, http://www.ncbi.nlm.nih.gov/pubmed/27421618