Periodic Reporting for period 1 - SimpleMinds (Simple minds – competition of parallel neural filters in behaviour selection of Drosophila)
Berichtszeitraum: 2023-08-01 bis 2026-01-31
Every day, animals must make important decisions that affect their survival and well-being. Choosing when to eat, sleep, or reproduce are just a few examples. Making the wrong choice - like sleeping when in danger or ignoring hunger for too long - can have serious consequences, not only for the individual but sometimes even for the species and the environment. These basic needs are often in conflict with each other, and it’s clear that the brain must have a way of deciding which behaviour is most important at any given moment.
Interestingly, we usually don’t do more than one of these things at once - it's hard to eat and sleep at the same time. This suggests that different brain systems compete with each other to decide what we should do next. But how exactly does the brain ‘make up its mind’? This is one of the big unanswered questions in neuroscience.
This project will explore how decision-making works in the brain using the vinegar fly – commonly also referred to as fruit fly - (Drosophila melanogaster) as a model. Although the brains are simple in number of nerve cells compared to humans, the fruit fly’s brain still needs to choose between different behaviours to survive. Its smaller brain and well-known biology make it a powerful model for understanding how decision-making can work in animals.
Our main hypothesis is that different needs, like hunger or sleepiness, are represented in the brain by separate ‘filters’ that control how incoming sensory information is relayed to other brain areas and processed. These filters compete with each other, and whichever one wins at a given time determines what the animal will do next. We will test this idea at several levels, from the role of molecules, to groups of neurons, to brain-wide patterns of activity.
By revealing the basic neural mechanisms that enable animals to choose between conflicting needs, this project will address a central question in neuroscience: how brains - even simple ones - implement intelligent decision-making. This can have broad relevance: it could provide insight into how more complex animals (including humans) make decisions and what goes wrong in mental health conditions where decision-making is impaired, such as in depression, anxiety, or addiction. Additionally, understanding how simple brains handle complex tasks may inspire new approaches in artificial intelligence and robotics.
Interestingly, we usually don’t do more than one of these things at once - it's hard to eat and sleep at the same time. This suggests that different brain systems compete with each other to decide what we should do next. But how exactly does the brain ‘make up its mind’? This is one of the big unanswered questions in neuroscience.
This project will explore how decision-making works in the brain using the vinegar fly – commonly also referred to as fruit fly - (Drosophila melanogaster) as a model. Although the brains are simple in number of nerve cells compared to humans, the fruit fly’s brain still needs to choose between different behaviours to survive. Its smaller brain and well-known biology make it a powerful model for understanding how decision-making can work in animals.
Our main hypothesis is that different needs, like hunger or sleepiness, are represented in the brain by separate ‘filters’ that control how incoming sensory information is relayed to other brain areas and processed. These filters compete with each other, and whichever one wins at a given time determines what the animal will do next. We will test this idea at several levels, from the role of molecules, to groups of neurons, to brain-wide patterns of activity.
By revealing the basic neural mechanisms that enable animals to choose between conflicting needs, this project will address a central question in neuroscience: how brains - even simple ones - implement intelligent decision-making. This can have broad relevance: it could provide insight into how more complex animals (including humans) make decisions and what goes wrong in mental health conditions where decision-making is impaired, such as in depression, anxiety, or addiction. Additionally, understanding how simple brains handle complex tasks may inspire new approaches in artificial intelligence and robotics.
This project investigates how neural networks in Drosophila melanogaster employ filtering mechanisms to prioritize behaviours depending on internal states such as hunger or sleep. Using electrophysiology, imaging, molecular genetics, and - in collaboration - computational modelling, we address this question across molecular, cellular, network, and behavioural levels.
In the first objective, we characterized neural filter properties in the central complex and mushroom body pathways. We identified antagonistic activity between R5 and helicon neurons regulating sleep and locomotion and demonstrated that filter efficacy in downstream head-direction neurons is modulated by sleep pressure and circadian factors. These findings were integrated into a theoretical model and published (Raccuglia et al., 2025, Nature). We are expanding such investigations in the context of hunger.
In the second objective, we uncovered molecular determinants shaping filter function, while in a third objective, we investigate interactions between filters.
In the first objective, we characterized neural filter properties in the central complex and mushroom body pathways. We identified antagonistic activity between R5 and helicon neurons regulating sleep and locomotion and demonstrated that filter efficacy in downstream head-direction neurons is modulated by sleep pressure and circadian factors. These findings were integrated into a theoretical model and published (Raccuglia et al., 2025, Nature). We are expanding such investigations in the context of hunger.
In the second objective, we uncovered molecular determinants shaping filter function, while in a third objective, we investigate interactions between filters.
Our findings allow to further investigate a neural filter hypothesis for prioritisation of relevant sensory stimuli that match a specific need, such as hunger or sleep.