Author: Marina Rodríguez Rubio
These are neurons! This is how we, scientists, can see the neurons in the lab. Beautiful right? That’s why we like our job.
But… What exactly are we seeing? Neurons are cells that are present in the brain and are responsible for all our thoughts, including those we are not aware of. Otherwise we would need to remind our heart to beat all the time, but thankfully our neurons do it automatically for us. So, in our brains there are approximately 86.000.000.000 neurons taking care of all the thoughts running through our heads. But in this picture there are just a few. The neurons, though, don’t have these colours in reality. We need to put colours, otherwise we wouldn’t see anything! Everything would be whitish, and we would not be able to distinguish anything. So we put one colour to each thing we want to see. The little blue circles are the nuclei of the cells. All the cells have nuclei, that’s where the cells store all the information they need for functioning (commonly known as DNA). So in blue you can see the central core of all the cells present in the picture. In green we labelled the neurons. The green has a different shape from the blue circles, because neurons are not circular. Each neuron contains one nucleus but each neuron also has thin arms that it uses to connect to other neurons. Thanks to those long green arms, neurons can share information and influence one another. Finally, in red we have the younger neurons, the baby neurons that will become green and will extend their arms further to get in touch with other neurons.
Now we know we have a picture of neurons talking to each other and that there are some that are younger than the others. But, where does this tissue come from? Whose brain are these neurons from?
I’ll give you a hint: These neurons are human, they have human DNA, human genetic information. Then you might guess that these neurons come from a human brain?
Well, no, these neurons don’t come from a human brain.
How is this possible? Human neurons that don’t come from a human brain?
Well, these human neurons are grown in the lab. We grow them from cells that come from humans. We can take cells from the skin of someone and give them specific food and conditions to become neurons. So even if these neurons don’t come from a human brain, they are still human, because they contain human DNA.
Why is this so important? Why don’t we just study the neurons in animals instead of growing them from cells that come from humans? That sounds so complicated… Well, it is certainly complicated and a big challenge, but it is tremendously important.
We, scientists, study the brain because we want to understand better the most complex organ in our body. Because when the connections between neurons fail, we, humans, suffer from terrible diseases such as Parkinson, Alzheimer or Huntington. But we still don’t understand these diseases and there is no cure for any of them! What is happening? Traditionally these diseases have been studied only in animals, mice for instance, that don’t naturally develop human neurodegenerative diseases. For these reason, we have found some possible cures that worked well in animals, but ended up failing when tested in humans with the actual disease (a famous example: NXY-059). To avoid this, we have to include other complementary studies, we NEED to include these human neurons grown in the lab. We need to test in human neurons the drugs that we develop to cure humans, before treating humans. And this is now possible.