December 5, 2023

Harvard Scientists Reveal How Squid and Octopus Get Their Big Brains

They were then able to track those cells through the development of the nervous system in the retina. The membranes of the cells in the eye are identified with a fluorescent color enabling us to imagine individual cell habits during development. The scientists from the Koenig Lab focused on the retina of a squid called Doryteuthis pealeii, more merely understood as a type of longfin squid. They created unique tools and utilized innovative microscopic lens that might take high-resolution images every ten minutes for hours on end to see how individual cells behave. The scientists utilized fluorescent dyes to mark the cells so they could map and track them.

Four squid embryos in their egg sac. These are the squid types Doryteuthis pealeii. Credit: Kristen Koenig
Cephalopods were found to have similar brain development to vertebrates in a brand-new study.
Cephalopods, that include octopuses, squid, and cuttlefish, show impressive habits such as the capability to rapidly adjust their appearance to blend into their environments, interact with one another, demonstrate spatial learning, and usage tools to resolve problems. Their high level of intelligence even enables them to experience dullness.
Its obvious what makes it possible: Cephalopods, consisting of octopuses, squid, and cuttlefish, have the most complex brains of any invertebrates. The process of how they develop these big brains has actually remained a secret. A Harvard University laboratory studying the visual system of these animals, which is where most of their main processing tissue is focused, believes they have made significant progress in comprehending the procedure. The process, they state, looks remarkably familiar.
Scientists from the FAS Center for Systems Biology describe how they used a brand-new live-imaging strategy to view nerve cells being produced in the embryo in practically real time. They were then able to track those cells through the development of the nervous system in the retina. What they saw stunned them.

This is an example of the live imaging information produced in this paper. The membranes of the cells in the eye are identified with a fluorescent dye enabling us to imagine individual cell habits throughout advancement. Credit: Kristen Koenig
The neural stem cells they tracked behaved strangely similar to the method these cells behave in vertebrates during the development of their nerve system. It suggests that vertebrates and cephalopods, in spite of diverging from each other 500 million years ago, not just are utilizing similar systems to make their big brains but that this process and the way the cells act, divide, and are shaped might essentially design the plan required to develop this type of nervous system.
” Our conclusions were unexpected because a lot of what we understand about anxious system advancement in vertebrates has long been believed to be special to that lineage,” stated Kristen Koenig, a John Harvard Distinguished Fellow and senior author of the research study. “By observing the reality that the process is really similar, what it suggested to us is that these two separately developed large nerve systems are utilizing the same systems to build them. What that recommends is that those mechanisms– those tools– the animals utilize throughout development may be crucial for developing huge nerve systems.”
The researchers from the Koenig Lab concentrated on the retina of a squid called Doryteuthis pealeii, more simply called a type of longfin squid. The squid grow to be about a foot long and are abundant in the northwest Atlantic Ocean. As embryos, they look rather charming with huge eyes and big heads.
The researchers utilized comparable strategies to those made popular to study design organisms, like fruit flies and zebrafish. They developed unique tools and used cutting-edge microscopic lens that could take high-resolution images every 10 minutes for hours on end to see how private cells act. The scientists used fluorescent dyes to mark the cells so they could map and track them.
This live-imaging method enabled the team to observe stem cells called neural progenitor cells and how they are organized. The cells form an unique kind of structure called a pseudostratified epithelium. Its highlight is the cells are extended so they can be densely packed. The researchers also saw the nucleus of these structures go up and down before and after dividing. This motion is crucial for keeping the tissue arranged and development continuing, they said.
This type of structure is universal in how vertebrate species establish their brain and eyes. Historically, it was considered one of the reasons the vertebrate anxious system might grow so large and complex. Scientists have observed examples of this type of neural epithelium in other animals, but the squid tissue they looked at in this instance was unusually comparable to vertebrate tissues in its size, company, and the way the nucleus moved.
The research was led by Francesca R. Napoli and Christina M. Daly, research study assistants in the Koenig Lab.
Next, the laboratory plans to take a look at how various cell enters cephalopod brains emerge. Koenig desires to figure out whether theyre expressed at various times, how they decide to turn into one kind of nerve cell versus another, and whether this action is similar across types.
Koenig is excited about the prospective discoveries that lie ahead.
” One of the huge takeaways from this type of work is simply how valuable it is to study the diversity of life,” Koenig said. “By studying this diversity, you can actually truly come back to fundamental concepts about even our own advancement and our own biomedically appropriate concerns. You can really speak to those concerns.”
Reference: “Cephalopod retinal advancement shows vertebrate-like systems of neurogenesis” by Francesca R. Napoli, Christina M. Daly, Stephanie Neal, Kyle J. McCulloch, Alexandra R. Zaloga, Alicia Liu and Kristen M. Koenig, 9 November 2022, Current Biology.DOI: 10.1016/ j.cub.2022.10.027.