One great brain hack would be to improve your brain efficiency.
Our brains have evolved to use more and more of the total energy that we intake in effort to have higher functioning brains (see previous post).
Additionally, as we age our brain becomes less efficient – it not only feels this way but scientific research also supports this notion. But what are the mechanisms behind the reduced brain efficiency as we age and is there anything we can do about it?
Efficiency in this case is the metabolic cost (energy via food consumed) versus brain information processing capability (you know that whole reduce prediction error and survive thing).
The nervous system like the internet (and ecosystem) is a complex network with various connections between different brain areas (which has evolved to maximize our survivability). In general the brain has small-network properties (many local connection with few long range connections). It is suggested that the small-network assembly evolved in the brain to maximize information processing efficiency while minimizing cost (an optimization problem). The evolving of the brain is a wiring problem (just like computer chip or internet design), with a very real limit of energy. And while shorter connections would be the best energy solution there is the opposite evolutionary drive for long distance connections to bring about more complex connections – better thinking capacity (due to full integration of all available incoming data and processing). So a push pull problem.
Achard and Bullmore (2007) (freely available) measured the efficiency and cost of the human brain functional networks. What is interesting about this work is that it combines network thinking (think internet, math) and the brain. They specifically measured functional connectivity between 90 cortical and subcortical regions. In older people (66.5 years old) compared to younger (24.7 years old) the efficiency was disproportionally reduced (compared to cost). This was both for local and global connectivity.
In general in the older subjects there was reduced efficiency in hubs such as dorsal cingulate, middle frontal and inferior temporal gyri.
Well so far they are telling us what we already know; as we age our brain has reduced efficiency. But the question becomes why is an older brain less efficient? We could look at the hundreds/thousands of protein that are altered as we age. Possibly a needle in a haystack problem. One of the many proteins that are altered with age is the level of the D2 receptor (which decreases with age) for dopamine – is this a possible culprit?
Therefore, the researchers used an antagonist (blocking compound) to the D2 receptor and found very similar results as the effect of aging on brain efficiency (reduction both locally and globally). Interestingly, efficiency was reduced in both the old and young subjects. One might have hypothesized that either there would be a floor effect in the old (they couldn’t become that much less efficient) or that the young would have enough buffer and that even with a reduction in a component of efficiency (e.g D2) that the system would be robust enough to maintain efficiency. However, both groups had a reduction in efficiency, though overall there was less efficiency lost in the younger group.
Additionally, there was a greater reduction in brain efficiency with aging as compared to D2 blocking, suggesting that the reduction of D2 with aging is not the only thing contributing to the reduced brain efficiency – but at least it appears to be an important factor.
The similar results with age and D2 blocking suggest that the dopamine system may be involved in optimizing the economical performance of the brain. Now what this means is:
As people age not only is there a reduction of dopamine cell bodies but also decreased density of dopamine projections to the cortex and striatum. Additionally, there is also a reduction of D2 receptors in the striatum and overall these changes appear to have a direct impact on the brain’s energy efficiency.
Now what else, other than age, may cause a reduction in dopamine, or more specifically the D2 receptor? Obese people have lower D2 binding levels. This would suggest that obese people brain’s may be less efficient. It is even conceivable the excess calories that obese people are consuming results in a reduction in efficiency since the brain doesn’t need to be so efficient (abundant supply of energy) (but this is another chicken or egg problem). At least these are testable hypotheses.
Additionally, there is a specific polymorphism in the D2 receptor (A1+ allele) that results in a 20-30% reduction in D2 density in the striatum. Would this group of people also have a reduction in brain efficiency? This has not been tested as far as I know.
How can you increase your D2 levels so you can improve your brain efficiency ?
I am guessing you have already figured it out – research indicates exercise increases the level of the D2 receptor (only tested in the rat at this point).
Take home message:
Brain hack to improve brain efficiency: exercise to increase the level of the D2 receptor to improve your brain efficiency.
Do not become overweight since this appears to lower D2 levels. And since D2 levels also decreases with age all the more impetus to exercise to starve off the age induced reduction in brain efficiency. Once again, get out there and exercise to improve your brain health.
There are possibly other ways to increase your D2 level and hence your brain efficiency – I will cover them at another time.