Fluorescent image of the octopus brain showing the location of different various types of neurons Credit: Niell Lab
Its tough for the octopus to select simply one celebration technique. This spectacular animal swims by means of jet propulsion, shoots dark chemicals at its enemies, and can alter its skin to blend in with its environments within seconds.
Now, a group of University of Oregon (UO) scientists has investigated yet another distinctive feature of this eight-armed marine animal: its outstanding visual capabilities.
They lay out an in-depth map of the octopuss visual system in a new clinical paper. In the map, they classify different types of nerve cells in a part of the brain devoted to vision.
In the map, they classify various types of nerve cells in a part of the brain devoted to vision. Unlike mice, which are not known for having good vision, “octopuses have an amazing visual system, and a large fraction of their brain is devoted to visual processing,” Niell said. The octopus brain keeps growing and including new nerve cells over the animals life-span. These immature neurons, not yet incorporated into brain circuits, were a sign of the brain in the procedure of expanding!
Theyre now working to map the octopus brain beyond the optic lobe, seeing how some of the genes they focused on in this study reveal up somewhere else in the brain.
The team reports their findings today (October 31) in the journal Current Biology.
Cris Niells lab at the UO research studies vision, mainly in mice. A few years ago, postdoc Judit Pungor brought a new types to the lab– the California two-spot octopus.
Although it is not generally utilized as a research study subject in the lab, this cephalopod rapidly recorded the interest of UO neuroscientists. Unlike mice, which are not known for having great vision, “octopuses have a fantastic visual system, and a big portion of their brain is dedicated to visual processing,” Niell said. “They have an eye thats remarkably similar to the human eye, however after that, the brain is completely various.
The last common ancestor between humans and octopuses was 500 million years earlier, and the species have because evolved in extremely different contexts. Scientists didnt know whether the parallels in visual systems extended beyond the eyes, or whether the octopus was rather using totally various kinds of neurons and brain circuits to attain comparable outcomes.
” Seeing how the octopus eye convergently evolved similarly to ours, its cool to think about how the octopus visual system might be a model for comprehending brain complexity more generally,” stated Mea Songco-Casey, a college student in Niells laboratory and the first author on the paper. “For example, exist essential cell types that are needed for this really smart, complex brain?”.
Here, the team used genetic strategies to recognize different kinds of neurons in the octopuss optic lobe, the part of the brain thats dedicated to vision.
They selected six significant classes of nerve cells, distinguished based on the chemical signals they send out. Looking at the activity of particular genes in those neurons then revealed more subtypes, offering clues to more specific functions.
In some cases, the scientists determined particular groups of neurons in unique spatial plans– for instance, a ring of neurons around the optic lobe that all signal using a particle called octopamine. Fruit flies usage this molecule, which is similar to adrenaline, to increase visual processing when the fly is active. It could possibly have a comparable function in octopuses.
” Now that we understand theres this very particular cell type, we can begin to enter and determine what it does,” Niell stated.
About a 3rd of the neurons in the data didnt rather look totally developed. The octopus brain keeps growing and adding brand-new nerve cells over the animals life-span. These immature neurons, not yet integrated into brain circuits, were a sign of the brain in the procedure of broadening!
However, the map didnt expose sets of nerve cells that clearly transferred over from humans or other mammalian brains, as the scientists believed it might.
” At the apparent level, the nerve cells dont map onto each other– theyre utilizing various neurotransmitters,” Niell said. “But perhaps theyre doing the very same kinds of calculations, simply in a various way.”.
Digging deeper will likewise require getting a much better manage on cephalopod genes. Due to the fact that the octopus hasnt generally been used as a laboratory animal, a number of the tools that are used for exact hereditary adjustment in fruit flies or mice do not yet exist for the octopus, stated Gabby Coffing, a college student in Andrew Kerns laboratory who worked on the research study.
” There are a lot of genes where we have no concept what their function is, due to the fact that we have not sequenced the genomes of a great deal of cephalopods,” Pungor said. Without hereditary data from related species as a point of comparison, its more difficult to deduce the function of particular nerve cells.
Niells group is up for the obstacle. Theyre now working to map the octopus brain beyond the optic lobe, seeing how a few of the genes they focused on in this research study show up in other places in the brain. They are also recording from nerve cells in the optic lobe, to determine how they process the visual scene.
In time, their research may make these strange marine animals a little less murky– and shine a little light on our own development, too.
Recommendation: “Cell types and molecular architecture of the Octopus bimaculoides visual system” 31 October 2022, Current Biology.DOI: 10.1016/ j.cub.2022.10.015.