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).
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
More Quick Hits
Your brain on near-death experiences
Near-death experiences have fascinated many people ever since they have been reported. And these experiences guide our view of how we die: the memories of your life passing in front of your eyes, the tunnel of light, the floating movement towards a bright light....
Social networks grow your brain
The headline is a bit “click baity” but it is what a group of researchers found. To be more specific they found in macaques (cute monkeys) in the wild that having more grooming partners grew different regions of the brain. Grooming is the primate version of having a...
What do creative brains look like?
We’d probably all be happy to be a bit more creative — though research into our own opinions show that many people do actually consider themselves to be above average in creativity. An obvious self-bias. This is where scientists who study creativity come in and find...
New gender biases discovered
There have been many studies on gender biases, and I have followed, written, and spoken about many of these biases over the years (over a decade actually) but two studies have just come out that caught my eye. One out of New York University focused on gender natural...
Growth of your brain over your life
So, we all know that our brain grows very quickly as babies and children and then after a certain age, younger than some of us may like to think, there begins a slow decline. But precisely what and how is the question. Well, this is a question that an international...
How to reduce loneliness
I have reported multiple times on loneliness during the pandemic – mostly because interest and research into loneliness has taken a large uptick. I have also reported on how to combat this and was happy to see that a piece of research just out proved what I had...