Scientists have just grown one of the most sophisticated mini brains in a petri dish!
But even crazier, the mini brain attached itself to a spinal cord and muscle tissue
that twitched!
Granted, this tiny brain was about the size of a lentil, but this still holds incredible
promise for the future of how we study our brains.
Now, you might be wondering why would we grow brains in the first place.
Well in the past, scientists were confined to studying the brain during autopsies, but
observing a dead brain could only get us so far.
What neuroscientists really want to know is how the human brain and nervous system develop.
Yes, we have MRI’s, EEGs and CT scans etc., which capture brain activity and have taught
us a lot about what we know today.
But this new method brings us one step closer to trying to understand the cause and possibly
find treatments for neurological disorders.
Officially called, cerebral or brain organoids, these 3D tissues are generated from human
stem cells which allow modelling of brain development in vitro.
Essentially allowing scientists to monitor brain development in a petri dish.
Now, we’ve been able to grow these organoids for a number of years, but this is the first
time that we’ve been able to attach a spinal cord to the tissue and see muscles contract.
So how did they do it?
Well, it all begins with stem cells taken from skin samples.
The stem cells are placed into 3D culture, where they undergo the initial phases of embryonic
development.
Next, they’re implanted in droplets of Matrigel, a gel containing proteins that support the
cells growth.
The droplets were then placed into an orbital shaker to help stimulate the stem cells to
transform and grow into the ball-like clusters of neural tissue.
This is where researchers had been running into problems.
Previously, once the organoid reached a certain size, its center wouldn’t get as many nutrients
or oxygen, putting an end to its growth.
And This where the new research comes in.
The scientists used an “air-liquid interface culture”, allowing the tissue access to
the nutrient rich-liquid below and the oxygen above.
To demonstrate this, they used a tiny slice of organoids on a porous membrane, surrounded
by a nutritious solution.
This allowed for the mini-brain model to develop in the dish for up to a year, thus producing
more sophisticated and mature organoids.
The next step was to monitor the neural activity of the mini brain model.
In order to do that, the researchers placed a spinal cord and some back muscle from a
mouse’s embryo next to the mini brain to observe whether or not its neurons would grow
out to connect with them.
Over the next 2 to 3 weeks, the neurons did just that and connected with the spinal cord
to send out electrical impulses.
And guess what happened?!
THE MUSCLES TWITCHED!
It’s the first time cerebral organoids had demonstrated an ability to control muscle
movement.
This new discovery also furthers our knowledge into understanding how neurons connect up
inside the brain and with the spinal cord.
The models can also allow scientists to monitor the progression of certain neurological disorders
like schizophrenia and autism, conditions where neuronal connections are believed to
be damaged.
But growing mini brains hasn’t come without controversy.
Some believe that regulations must be drawn in order to address the future implications
of this type of research.
For example, could these brains develop consciousness?
Well, at their current size, no.
The mini-brain is still only pea-sized and contains about a couple of million neurons,
now I know that sounds small, but it’s actually twice the number of neurons in a cockroach’s
brain.
Which suffice to say, is still pretty far away from a fully developed human brain that
has over 80 BILLION neurons.
Which is why the researchers acknowledge that their mini brain is far from reaching consciousness.
But what happens when these mini-brains continue to grow in size and complexity, will it become
an issue then?
It’s a question that some ethicists are pushing to find the answer to especially as
the research is moving so quickly.
But as research progresses, these miniature brains can start helping us to better understand
the fundamental questions about our brains.
So what do you think?
Should we be growing brains in a petri dish?
Let us know in the comments below and don’t forget to subscribe to Seeker for more science
in your day and thanks for watching Seeker.