Investing in a Digital Brain Bank

As many readers of this blog will know, the Centre for Brain Research has a world-renowned Human Brain Bank. This incredibly valuable scientific resource provides scientists with the opportunity to discover vital clues about brain diseases. Tissue from the New Zealand brain bank is sought after by scientists worldwide, sparking collaboration around the globe. Advances in modern science often necessitate collaboration between researchers with unique resources and scientific approaches.

brain bank Such collaboration has recently been made even easier with the emergence of a human brain bank in San Diego that digitizes all their specimens. The full article about this Digital Brain Library is available here – well worth a read. Each brain that is donated to the library goes through the usual preservation procedure and is then sliced over several days into over 2,000 slices that are only microns thick. Once stained, each slice is photographed at an incredibly high resolution and then digitized. One important feature of the digitization step is that it creates an online library of all the brains reassembled into their complete structures. This allows investigation of whole-brain connectivity that is not possible with single slice specimens.

However, what I think is even more exciting, is the fact that the digital library is open access. Anybody, anywhere in the world is able to view and learn from these brains. The powerful potential of crowd-sourcing to utilize the ideas and motivations of the general public should not be underestimated. Indeed, the article points out that Google Earth has enabled amateurs to make some remarkable discoveries, even ones that scientists missed. Could this Digital Brain Library be the Google Earth equivalent to reveal some of the mysteries of neurological diseases?

The idea of sharing such knowledge and utilizing the collective ‘brain power’ of the population has exciting possibilities. After all, “with enough curious eyes on a big enough dataset, you never know what someone will find.”

Does the brain benefit from mindful meditation?

It’s the beginning of February, and hopefully those of us who set goals for 2015 are on track. One of the things on my list for this year is to try mindful meditation. In a typical modern-day lifestyle it doesn’t seem surprising that taking some time each day to relax and clear the mind can show immediate improvements in focus and reduce stress levels. But are there any neurological benefits which can be longer lasting?

Meditating Buddha By Wikipedia Loves Art participant "Opal_Art_Seekers_4" [CC BY 2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons

Meditating Buddha By Wikipedia Loves Art participant “Opal_Art_Seekers_4” [CC BY 2.5 (http://creativecommons.org/licenses/by/2.5)%5D, via Wikimedia Commons

It’s worth acknowledging that there are several forms of meditation. I’ve been reading about mindful meditation, or focused attention. The goal of this practice is to keep the mind in the present moment, usually focusing on something simple like breathing. Sustaining a single thought without straying can certainly be hard work! It doesn’t, therefore, seem too surprising that consistent practice might be ‘training the brain.’

Several studies have shown that practicing mindful meditation is correlated with physical changes within the brain, especially changes to grey matter volume. Grey matter refers to neuron cell bodies and indicates neuron density. People who meditate have increased neuron density within the hippocampus (a structure integral to memory), brain stem (involved in regulating breathing and heart rate), and the frontal lobe (the location of several cognitive functions e.g. self-control), as well as decreased density in the amygdala (involved in anxiety and stress responses). Incredibly even just 8 weeks of practice appears to cause significant anatomical changes. These changes in form have been demonstrated using magnetic resonance imaging (MRI) and supported by behavioural data showing improved performance in related functions. There have even been suggestions that maintaining grey matter volume through mindful meditation has neuroprotective effects, helping to reduce age-related decline in cognitive function.

Studies have also demonstrated general improvements in mood and decreased stress levels from meditation in patients (e.g. multiple sclerosis and cancer) and healthy populations, possibly due to alterations in neural metabolites. Although significant time commitments were required in some studies (up to 5 hours a day), it also seems that 10 – 20 minutes a day can produce benefits.

So the evidence so far for neurological benefits seems fairly compelling. However it is important to keep in mind that in this field of research it is difficult to have placebo controlled and blinded studies, so we do have to interpret the research accordingly. In addition, the findings of structural differences in the brain are encouraging, but unfortunately correlation does not necessarily imply causation. Nevertheless, as there seems to be no harm associated with the practice and suggestions of benefit, potentially even long term, I’m off to find a quiet space for 20 minutes of mindful meditation!

The brain under pressure

Last week we read about what happens to our brain when we hold our breath and free dive. What about those of us who want less physically demanding diving? Do we experience similar physiological effects while SCUBA diving?

SCUBA diver

By Soljaguar (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)%5D, via Wikimedia Commons

Effectively, yes. Except SCUBA diving also introduces effects on the body from breathing air under pressure for an extended time period. For a recreational diver, nitrogen is our worst enemy. While we’re enjoying the eels, nitrogen is silently dissolving itself in our blood stream. Unlike oxygen, our body does not metabolize nitrogen, so it builds up in our tissue like carbon dioxide in a soft drink. If we stay down too long and ascend too quickly, the dissolved nitrogen will turn into bubbles like when you crack open that bottle of soft drink.

These are not the sort of entertaining bubbles you enjoyed as a kid – bubbles in tissue and blood are dangerous as they disrupt cells, causing a wide variety of symptoms known as decompression sickness. The smaller bubbles are less disruptive, most likely only causing limb and joint pain. The nickname of ‘the bends’ comes from the bent and twisted posture of suffers trying to relieve the pain in their limbs.

However if we were unlucky enough to get larger or a greater number of bubbles, we’d most likely start experiencing neurological symptoms. These can include headaches, stroke, paralysis, seizures, vestibular problems, inappropriate behaviour, and visual disturbances. The most common neurological complications of decompression sickness are those of numbness and paralysis of the legs, caused by a lesion around the 6th to 8th thoracic segment in the spinal cord. This is believed to be due to the increased susceptibility of this region to ischemia. However bubbles can also damage the nervous system by causing axon degeneration or even demyelination. Certain neurological conditions may be made worse, such as cerebral palsy, ADHD, and epilepsy.

Once you’ve had decompression sickness, you seem to be at an increased risk of getting it again, although the exact reason for this is unknown. There is unfortunately little scientific consensus as to the long-term effects of decompression sickness, mostly due to the difficulty of finding an adequate control group for reliable research. One suggested effect of repeated decompression sickness is osteonecrosis, or bone death, resulting from bubbles trapped in blood vessels that supply bone. Disruption of blood vessels may also cause an increased risk of associated neurological incidents such as stroke. Thankfully, people may recover from neurological damage through repeated treatments with oxygen in a high-pressure chamber.

Although unfortunately, you can have too much of a good thing. Prolonged breathing of too much oxygen at increased partial pressures has it’s own problems, namely oxygen toxicity. Central nervous system oxygen toxicity can cause disorientation, dizziness and nausea followed by seizures, resulting from oxidative damage to cell membranes. This is really only a risk for more advanced technical divers, who use various gas mixtures with enriched oxygen or who dive to depths greater than 60m with normal air.

This definitely isn’t meant to scare people off SCUBA diving! Recreational divers following the basics of their training will be well within safe limits. But be aware of the effects the increased pressure is having on your body.