How do cuttlefish instantly change their skin color based on what they see and feel?

Cuttlefish might be the most incredible species of life on Earth, or at least near the top of most lists.

Picture an underwater creature that boasts three hearts, pumps blue blood, and has skin that can flicker, change, and glow like the grand spectacle of Times Square.

The vibrant and mysterious Sepia bandensis, or as it is commonly known, the dwarf cuttlefish, is the center of a groundbreaking study.

Creating a brain atlas of the cuttlefish

Over a span of three years, an eclectic team of neuroscientists, data experts, and web designers from Columbia’s Zuckerman lab have been engaged in a project to understand the intricate workings of this fascinating cephalopod’s brain.

Their efforts have resulted in the creation of a brain atlas for the dwarf cuttlefish. This roadmap maps out, for the first time, the 32 lobes of its brain along with its unique cellular structure.

Being a master of disguise, the dwarf cuttlefish can change its skin pattern and texture in the blink of an eye to blend in with its surroundings.

This camouflage is directed by what the cuttlefish sees and its brain responds by controlling hundreds of thousands of cellular pixels in its skin. This extraordinary ability allows the cuttlefish to mirror its visual environment on its own skin.

Richard Axel’s lab is set on a quest to understand how this exceptional process works. According to Axel, understanding how visual information is processed in the brain, whether in cephalopods or humans, is one of the most compelling challenges in neuroscience.

In order to study the neural mechanisms of cuttlefish camouflage, the Axel lab had to record neuronal activity from the cuttlefish’s brain. But to extract the most significant information, a brain map was required, and until now, such a map wasn’t available.

Building the Cuttlebase

As part of their research, they worked on constructing a neuroanatomical atlas of the dwarf cuttlefish brain. Their findings have been published online in Current Biology, and they have launched a corresponding website, Cuttlebase.org.

Tessa G. Montague, the first author of the paper and a postdoctoral fellow in Axel’s lab, said, “One of my favorite approaches for learning about the brain is to study creatures that are highly specialized in particular behaviors or tasks…”

Montague went on to express hope that the brain atlas will help the scientific community understand the mechanisms cuttlefish use to express themselves through their skin, leading to broader insights into the workings of any brain.

Developing Cuttlebase required a diverse group of experts specializing in neuroscience, tissue imaging, computer programming, anatomy, and web design.

MRI scans of cuttlefish brains laid the foundation

The foundation of the brain atlas was laid using MRI scans of eight cuttlefish. A deep-learning algorithm was used to differentiate the brain-related data from the surrounding tissue in the scan.

According to Sabrina Gjerswold-Selleck, a co-author of the paper, the team was able to adapt a technique from previous work on mice brain scans. She said, “We were surprised how well we were able to adapt the technique.”

The task of defining the boundaries of each cuttlefish brain lobe was completed by comparing MRI scans to a few labeled brain images from the 1960s. This huge effort resulted in hundreds of grayscale images depicting the outlines of the brain regions.

The researchers then used histological techniques to upgrade their brain atlas, offering cellular resolution. This involved staining sections of cuttlefish brains to mark the locations of neurons, glial cells, and axons.

Eventually, the eight cuttlefish brain images were merged into a single atlas. They identified 32 lobes in total. Each lobe has specific biological functions and behaviors.

“The main purpose of the paper is to report the visualization and research tool, Cuttlebase, and to make it all freely available and easily accessible to everyone,” Montague said.

Cuttlebase is an incredible resource for all

The user-friendly features of Cuttlebase allow everyone to access and learn about the cuttlefish brain and its intricate workings. Cuttlebase has everything from detailed histological sections of different brain regions to a zoomable 3D model of the brain and even a full model of the cuttlefish’s 26 organs.

The website provides an immersive and educational experience. All of this is done in an effort to help researchers everywhere further their understanding of the cuttlefish brain.

Sukanya Aneja and Dana Elkis, part of the Cuttlebase team and co-authors of the paper, played leading roles in creating the website. Aneja shared the challenges they faced in making the complex data user-friendly and appealing to both scientists and non-scientists.

Elkis added that the site needed to integrate videos, images, 3D models, illustrations, charts, and diagrams to offer a comprehensive understanding of their research.

Isabelle Rieth, a former Cuttlebase team member, contributed her design skills to ensure the website was not just informative but also visually appealing. The result is a site filled with vibrant colors, aiding users in understanding what they are seeing.

The research team remains in awe of the amazing cuttlefish

Despite the extensive work and challenges the collaborators faced in bringing this project to fruition, their fascination for the dwarf cuttlefish remained undiminished.

Montague shared her amazement at watching the cuttlefish, stating, “When they’re camouflaging or communicating with each other, they’re effectively revealing to you on their skin what they see and how they feel.”

The results of this ambitious project have opened doors for a greater understanding of the dwarf cuttlefish and potentially shed light on the broader workings of the brain.

Through their efforts, the Axel lab, and all those involved, have provided a valuable resource for the continued exploration and study of this remarkable cephalopod.

More about cuttlefish

Cuttlefish, or the Sepiida order, are marine creatures that fall within the larger category of cephalopods, which also includes squids, octopuses, and nautiluses.

They are renowned for their intelligence and their unique physical attributes, such as their W-shaped pupils, color-changing skin, and an internal shell called the cuttlebone.

Here are some key aspects of cuttlefish:

Biology

Cuttlefish have soft bodies and a unique internal shell, the cuttlebone, which helps control buoyancy by changing the gas-to-liquid ratio inside the porous bone. Their bodies are often broad and flattened with a fin that fringes the body and aids in swimming. They have eight arms and two longer tentacles that are usually tucked away, which they use for catching prey.

Vision

Cuttlefish have highly developed eyes, which are believed to be fully developed before birth. This allows baby cuttlefish to observe their surroundings while still in the egg. Despite being colorblind, cuttlefish have one of the most sophisticated visual systems in the animal kingdom. They can perceive polarized light and have a wide field of vision.

Color Change and Camouflage

Cuttlefish are famous for their ability to rapidly alter their skin color and pattern. They can use this ability for communication or, more commonly, for camouflage to protect themselves from predators.

This is a result of specialized cells—chromatophores, iridophores, and leucophores—that are located in the upper layer of the skin and can be controlled to create complex and dynamic patterns.

Diet and Hunting

Cuttlefish are carnivorous. Their diet primarily consists of small molluscs, crabs, shrimp, fish, octopus, worms, and other cuttlefish. They hunt by stealth, sneaking up on or attracting their prey before seizing it with their tentacles.

Reproduction

Cuttlefish reproduce sexually, with males usually courting females with dazzling color displays. After mating, the female lays her eggs on the seafloor, often hiding them inside crevices or under ledges. Cuttlefish have a relatively short life cycle, living from one to two years on average.

Intelligence

Cuttlefish are considered highly intelligent among invertebrates, demonstrating a high degree of learning, adaptation, and memory use. They’ve been known to solve mazes, mimic other animals, and even use tools.

Threats

Natural predators of cuttlefish include dolphins, sharks, fish, seals, seabirds, and other cuttlefish. Humans also fish cuttlefish for food and, in some places, they are considered a delicacy. Cuttlebones are often used as a calcium supplement for pet birds. Pollution and habitat destruction also threaten cuttlefish populations.

While this information provides an overview of cuttlefish as a group, it’s worth noting that there is great diversity within this classification. Different species of cuttlefish may vary significantly in size, lifespan, behavior, and other characteristics.