Squid love to play pranks and how big their brains are

Cephalopods are capable of performing some impressive behaviors
.
They can quickly process information, change shapes, colors, and even textures to blend in with their surroundings
.
They can also communicate with each other, show signs of spatial learning, and use tools to solve problems
.
They are so smart that they can even get bored and start playing pranks
.

It's no secret that these marine animals, including octopuses, cuttlefish, and their cuttlefish cousins, have the most complex brains of any invertebrate on Earth
.
However, how cephalopods first developed such large brains remains a mystery
.
A lab at Harvard University has studied the visual systems of these mollusks — two-thirds of their central processing organization is concentrated — and believes they are close to
figuring it out.

In a new study, researchers at the FAS Center for Systems Biology describe how they used a new real-time imaging technique to observe the production
of neurons in squid embryos in near real time.
They were then able to track these cells
through the development of the retinal nervous system.

They were surprised to find that during nervous system development, these neural stem cells behave very similarly
to vertebrates.
The findings suggest that although vertebrates and cephalopods began to diverge 500 million years ago, the processes by which they develop large brains are similar
.
In addition, the way cells move, divide, and form may essentially follow a kind of blueprint
that this nervous system needs.

"Our conclusion is surprising because much of what we know about vertebrate nervous system development has long been thought to be specific to this lineage," said
Kristen Koenig, a distinguished researcher at John Harvard University and senior author of the study.
"By looking at the fact that this process is very similar, it shows us that these two very large nervous systems that evolved independently used the same mechanism to structure them
.
" This suggests that the same mechanisms that animals use during development — these tools — may be important
for building large nervous systems.
”

Scientists from Koenig's lab focused their attention on the retina of a squid called Doryteuthis pealeii, a simpler longfin offshore squid
.
This squid can grow up to a foot long and is abundant in
the northwestern Atlantic Ocean.
These embryos look like cute anime characters with big heads and eyes
.

https://news.
harvard.
edu/wp-content/uploads/2022/11/20220814_130049_1_12.
mp4

The researchers employed similar techniques
to those commonly used to study model organisms, such as flies and zebrafish.
They created special tools and used a cutting-edge microscope to take high-resolution images every 10 minutes to observe the behavior
of individual cells for hours on end.
The researchers used fluorescent dyes to label the cells so they could map them and track them
.

This real-time imaging technique allowed the team to look at stem cells known as neural progenitor cells and how they are organized
.
These cells form a special structure called the pseudolayered epithelium
.
Its main feature is that the cells are elongated so that they can be densely arranged
.
The researchers also saw the nuclei of these structures move
up and down before and after division.
They say this movement is important
to keep organization organized and allow for continued growth.

This structure is ubiquitous in
vertebrate brain and eye development.
This has long been thought to be one of the
reasons why vertebrate nervous systems are able to grow so large and complex.
Scientists have also observed this type of neuroepithelial cells in other animals, but the squid's tissue is also strikingly similar
to vertebrates in size, tissue, and nucleus movement.

Next, the lab plans to observe how different types of cells emerge
in cephalopod brains.
Koenig wanted to determine whether they were expressed at different times, how they decided to become one type of neuron rather than another, and whether the behavior was similar
across species.

Koenig said: "One of the great takeaways from this kind of work is to study the value of
diversity in life.
By studying this diversity, you can actually go back to the basic idea
of our own development and biomedical-related issues.
You can really answer these questions
.
”