Quick Hits
Daily brief research updates from the cognitive sciences

There are different types of dark matter in the brain. Matter that is often little researched or unknown to different population groups. I have written previously about glial cells and their contribution to just about everything, something neuroscientists know a lot about, to electrical neurons, that have been vastly under researched.

But now some researchers have made some discoveries in another area, and that is that of silent synapses. Synapses are the connections between your brain cells. The current understanding is that as you learn, develop new skills, synapses connect, and strengthen and build the networks in your brain – this is how your brain is continually growing and changing. However, these would always be part of a network. Silent, inactive synapses have been seen in the brains of developing mice so it was thought they played a key role in the developing brain but not in adults.

However, in an unexpected discovery MIT researchers have found silent synapses at levels 10 times higher than expected. The researchers were not actually looking for silent synapses but trying to measure neurotransmitter receptors on the branches of neurons. Some of these branches and connections, known as filopodia, are extremely fine and small and are difficult, or impossible, to see with standard imaging techniques.

On discovering these in such high quantities they then proceeded to investigate whether they were indeed silent synapses by attempting to stimulate these with a combination of a neurotransmitter and an electrical stimulus. They found that indeed these were silent but could grow into active synapses much quicker than by altering mature synapses.

That’s good news and this explains how we can learn things quicker – having silent synapses allows rapid learning and being able to build new memories without building whole new synapses.

Whether this is different between different people is another question – but I am hoping I have a bunch of silent synapses waiting to spring into action when I engage with new material – such as writing this article – go silent synapses, go!

Andy Habermacher

Andy is author of leading brains Review, Neuroleadership, and multiple other books. He has been intensively involved in writing and research into neuroleadership and is considered one of Europe’s leading experts. He is also a well-known public speaker, speaking on the brain and human behaviour.

Andy is also a masters athlete (middle distance running) and competes regularly at international competitions (and holds a few national records in his age category).

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References

Vardalaki, D., Chung, K. & Harnett, M.T. 
Filopodia are a structural substrate for silent synapses in adult neocortex. 
Nature, 2022
DOI: 10.1038/s41586-022-05483-6

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Quick Hits
Daily brief research updates from the cognitive sciences

The headline caught my eye also. I’ve written multiple times, as many of you who follow my writing will know, on sleep, but also chronotypes: having a different daily wake and sleep rhythms. I am a bit of an owl – I tend to go to bed later and feel better when I get up later. I have however, been able to retrain myself and get up consistently early and keep my rhythm almost every day. I’m not a bad get-out-of-bedder but I also don’t bounce out of bed with a spring in my step either. So, when scientists say they know how to wake up alert, well, it makes me alert!

So, who are these scientists and what did they do?

This was a group of researchers from the Centre of Sleep Science at Berkely University who conducted a detailed analysis of 833 participants over a two-week period, with different sleep times and different types of breakfast. Their sleep was tracked with smart watches, they also had glucose measurements. Of note is that twins, both identical and fraternal, were in the study to help disentangle genetic effects.

The surprise, which kind of contradicts other studies on chronotypes, is that genetics only accounted for 25% of the variance in alertness in the morning. So, you will be itching to know what else contributed to this alertness.

There were four factors:

1. Sleeping longer and later than you usually do. Seems like a no-brainer. But this was the most predictive aspect. It could be then that we just aren’t getting enough sleep in the first place. This might not be helpful for those who need to get up early for work (go to bed earlier, sweetie).
2. The next one was that of exercising the day before which the researchers noticed contributed to better sleep and enhanced mood.
3. A really important aspect was that of breakfast – the researchers noted that a breakfast high in simple sugars dramatically (negatively) impacted alertness and subsequent sleepiness. In contrast a breakfast with modest protein and complex carbohydrates was linked to revving up alertness.
4. The final factor was the glucose response – this could arguably be a genetic component: this can also be very individualised. But this is strongly influenced by the afore-mentioned breakfast.

So, sadly, nothing dramatic there. But then again it does show, with a good body of evidence, that there are ways to boost alertness and wakefulness in the morning and most of these are under our control.

I had high hopes for the article – but as is often the case, I do most of these already – I am a masters athlete so train most days, I have a healthy fibre rich breakfast, and walk straight after breakfast to energise myself and get some daylight (when it’s light that is). However, I could do with some help getting to bed earlier, I tend to postpose my bedtime – being a bit of an owl…then again, I’m not bad at getting up – just it would be nice to be a bit more sprightly in the morning!

It must also be noted that the societal cost of sleepiness and drowsiness are significant, in fact it is deadly, the number of accidents not to mention major catastrophes that have been influenced by sleepiness is not to be underestimated: the Exxon Valdez oil spill in Alaska, the Three Mile Island nuclear meltdown in Pennsylvania and an even worse nuclear accident in Chernobyl.

So, it is good and important to know that a lot of this is under our control – and the “I’m not a morning person” might not be as true as you may believe!

Andy Habermacher

Andy is author of leading brains Review, Neuroleadership, and multiple other books. He has been intensively involved in writing and research into neuroleadership and is considered one of Europe’s leading experts. He is also a well-known public speaker, speaking on the brain and human behaviour.

Andy is also a masters athlete (middle distance running) and competes regularly at international competitions (and holds a few national records in his age category).

twitter / LinkedIn

References

Raphael Vallat, Sarah E. Berry, Neli Tsereteli, Joan Capdevila, Haya Al Khatib, Ana M. Valdes, Linda M. Delahanty, David A. Drew, Andrew T. Chan, Jonathan Wolf, Paul W. Franks, Tim D. Spector, Matthew P. Walker.
How people wake up is associated with previous night’s sleep together with physical activity and food intake.
Nature Communications, 2022; 13 (1)
DOI: 10.1038/s41467-022-34503-2

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