At MPINB, we focus on different animal species and on their special behaviors to unravel general principles of neural information processing and decision-making in the brain.
Even tiny brains are capable of solving intricate tasks during orientation. Our Neurobiology of Flight Control lab studies flight control in the common model organism Drosophila melanogaster, also known as the fruit fly. Fruit flies are very agile and strong fliers. When it comes to navigation, Drosophila primarily relies on its visual sense. The optical flow, which is the motion pattern generated at the fly's eye while it moves relative to its surroundings, plays a crucial role in helping the animal stabilize its flight. To avoid obstacles or sudden threats, like a flyswatter, the fly can swiftly change its flight direction with lightning-fast body movements called saccades, reaching rotation speeds of up to 5000 degrees per second. While this speed is incredible, what's even more remarkable is the process that precedes this movement: the fly must decide whether to react to a stimulus or not. How can a brain the size of a grain of salt distinguish between important and non-important information within the enormous stream of sensory input it receives during flight? Our team of researchers aims to understand how a fly’s brain controls such a complex behavior as course control during flight. The ultimate goal is to gain insights into general mechanisms that underlie decision-making in animals. Watch the interview with Group Leader Bettina Schnell, for more information.
Since 2019, our animal house is home to the African mole-rat Fukomys anselli. These social mammals live in complete darkness in large underground mazes using the Earth’s magnetic field to find their way. The ability to use magnetic fields for both short- and long-range navigation is already known from sea turtles, birds, fish, crustaceans and insects. Our Neurobiology of Magnetoreception Lab is dedicated to identifying the sensory structures and the neuronal pathways within the brain to provide further insights into how mammals can sense and use weak electromagnetic fields for orientation. One interesting fact is already known: Unlike birds and sea turtles, which perceive the inclination angle of the Earth's magnetic field, mole-rats possess a polarity compass. For more details, watch the interview with Group Leader Pascal Malkemper.
At MPINB, we also explore how mice and rats perceive and navigate their surroundings. How can a mouse quickly chase after a cricket while simultaneously paying attention to overhead predators? What is going on in the brain of a rat when it makes the decision whether or not it can jump over a large gap? Our Department of Behavior and Brain Organization is focusing on understanding the neuronal mechanisms underlying vision-based decision-making in freely moving animals. The researchers develop cutting-edge tools and techniques to quantify behavior in high resolution and to study neural activity. One example is the new miniature head-mounted three-photon microscope that weighs only two grams and is capable of measuring neuronal activity in all cortical layers, even the deepest ones. Watch our interview introducing our new microscope. Another example is the new approach developed by this department to quantify skeletal motion in freely moving rodents in a new level of accuracy and detail. Read our press release.
Similar to navigating through the air, navigation in water involves moving within a three-dimensional space. The challenges posed by this environment are difficult for us humans to fully comprehend. Animals that reside underwater typically possess eyes adapted to the refractive index of water, which differs from that of the air. One of the remarkable creatures housed in our animal facility is the four-eyed fish, Anableps anableps. Its eyes have evolved in a manner that enables it to simultaneously see both above and below the water's surface. Researchers from the Department of Computational Neuroethology are investigating the visual system adaptations of this fish, which are well-suited for its lifestyle of hunting insects on the water's surface. The department also studies vision and decision-making in various other fish species such as Danionella cerebrum and the zebrafish, Danio rerio. Furthermore, the department works with the western clawed frog, Xenopus tropicalis. Given its transformation from a tadpole into a four-limbed creature, this animal serves as an excellent model organism for understanding the development of the locomotor system and its role in navigation.
Although we may not often think of it this way, searching for food and the act of feeding are exceedingly intricate tasks for most animals. They have to sense and to follow cues to locate their food. If the food happens to be a living creature, the animal must engage in hunting and capturing first. All the while, the animal must remain attentive to the information collected by its sensory systems,
continually assessing whether it is safe to continue feeding or if it would be wiser to flee or fight to avoid ending up on the menu of another predator itself.
Using specialized head-mounted cameras and a digitization approach, our Department of Behavior and Brain Organization has reconstructed what a mouse sees during its hunt for prey. Essentially, a view through the eyes of a mouse. Our next steps involve integrating this data with recordings from nerve cells in the brain to delve deeper into understanding how the brain orchestrates complex visually guided behaviors. Don't miss our our video "seeing what they see" for more insights.
Two of our research groups study feeding behavior of smaller animals, specifically two different species of nematodes. Why do we study nematodes? We do have much more in common with these tiny roundworms than we might expect, which makes them excellent model organisms for cellular biology, evolutionary research, medical studies and neurobiology. One of the popular model organisms is Caenorhabditis elegans. To locate food, these worms must coordinate their movements and feeding rate based on internal state factors such as their appetite and external sensory inputs like the surrounding odors. Our Neural Information Flow lab studies how the very well-described nervous system of these tiny worms processes this diverse information and compresses it, finally leading to an altered behavior in the animals. The lab recently developed a method to simultaneously track the locomotion and feeding behavior of over 50 worms. Don’t miss our interview with Group Leader Monika Scholz for more details.
Our Genetics of Behavior Lab studies the roundworm Pristionchus pacificus. Unlike C. elegans, this worm has evolved adaptations for feeding on other worms (see Predation, cannibalism and kin-recognition).
In addition to our research on the popular model organism Caenorhabditis elegans (see "Foraging, hunting and feeding"), we also work with the less well-known relative named Pristionchus pacificus. These two nematodes last shared a common ancestor about 120 million years ago and accordingly, there are an array of behavioral differences between these species. Within the species of P. pacificus, there are two types of worms, distinctive by their different mouth parts. One feeds on bacteria only, the other type is omnivorous and feeds on other worms, including C. elegans, with the help of its specialized teeth-like structures in its mouth. Its own kin though do not end up on the menu. Our Genetics of Behavior Lab studies how these predation behaviors have evolved in these tiny worms and how they manage the challenges of recognizing who is family and who is not through their kin-recognition abilities. Watch our interview with Group Leader James Lightfoot.
Sleep is necessary for survival and important for many brain functions. For example, memory is consolidated and the brain gets rid of metabolites during sleep. The longer an animal stays awake, the more its sleep need increases. But how is sleep controlled and which cellular circuits in the brain are involved? How does the brain know when sleep is needed? Our Neural Circuits Lab studies sleep in the model organism Drosophila melanogaster. The researchers have developed a method to study neuronal activity in the tiny fruit fly in a virtual reality setup over multiple days. In this setup for live cell imaging the fly can walk, feed or sleep while at the same time activity of nerve cells in its brain is recorded. In this way, even slow changes such as those occurring during learning or during sleep can be analyzed.
Read more about the virtual reality setup for flies
Orientation behaviors are not exclusive to animals; even individual cells exhibit orientation, movement, and migration. Cells constantly encounter changing chemical cues and, to perform their functions, must execute real-time computations. For instance, how do individual cells maintain their course during migration when confronted with changes in their immediate surroundings? Our Cellular Computations and Learning lab has shown that cells possess a molecular form of working memory. The group develops a general theory on how cellular computations and learning emerges. Read their latest research news.