A seizure is often described as a sudden burst of uncontrolled electrical activity in the brain, but that description conceals an extraordinarily complex process. Within seconds, networks of neurons can shift from coordinated signaling into a state of excessive, synchronized activity. The event may begin in a small region and then move across interconnected areas, or it may recruit several regions almost simultaneously. Because the activity develops so quickly and inside a three-dimensional organ, researchers have struggled to observe the entire event with sufficient spatial and temporal detail. Conventional imaging methods can show activity across a flat plane, but they may miss what is happening above or below that slice.

The University of Georgia team addressed this problem by combining light-sheet microscopy with adaptive optics, creating an imaging system capable of capturing rapid changes throughout the brain of a living zebrafish larva. In light-sheet microscopy, a thin plane of laser light illuminates only one narrow slice of the specimen at a time. Fluorescent signals produced by active neurons can then be recorded by a camera positioned perpendicular to the light sheet. By rapidly moving the illuminated plane through the sample and assembling the resulting images, the microscope generates a volumetric view of neural activity. The approach limits unnecessary illumination and reduces background noise, allowing researchers to image delicate living organisms at high speed.

The system’s adaptive optics component further improves the quality of the images. When light passes through biological tissue, it encounters structures with different optical properties. Those variations bend and scatter the light, distorting the signal before it reaches the microscope. The result is a blurred image, particularly when researchers attempt to look deep into tissue or across an extended volume. Adaptive optics corrects these distortions by measuring how the light has been altered and adjusting the optical system to compensate. The technology was originally developed for astronomy, where it is used to correct the blurring caused by Earth’s atmosphere and produce sharper images of distant stars and galaxies.

In the new experiments, zebrafish larvae served as a transparent and experimentally accessible model for studying seizure activity. Zebrafish are widely used in neuroscience because their early-stage bodies are small, their nervous systems share important biological features with those of other vertebrates and their developing tissues can often be observed with minimal obstruction. Their transparency is especially valuable for optical imaging, making it possible to monitor activity across the brain without the extensive surgical procedures required in many mammalian models. The larvae also provide a compact system in which researchers can follow the movement of electrical activity across multiple brain regions at once.

The recorded seizure appeared to begin toward the rear of the larval brain before advancing toward the front. As the activity moved forward, it reached the optic tectum, a midbrain structure involved in processing visual information. In zebrafish, the optic tectum plays a central role in interpreting what the animal sees, coordinating eye movements and generating behavioral responses to visual stimuli. The imaging sequence showed that the abnormal activity did not remain confined to a single location. Instead, it propagated through the brain in a spatially organized pattern before gradually weakening over several seconds. The resulting footage provides a rare start-to-finish view of a seizure spreading through a living vertebrate brain.

That sequence is significant because seizure propagation is not merely a visual phenomenon; it reflects the organization of the underlying neural circuits. Neurons communicate through electrical and chemical signals, and their connections determine how activity can travel from one population to another. During a seizure, normal regulatory mechanisms that prevent excessive excitation can become overwhelmed or disrupted. Mapping the route of the event in three dimensions may help researchers identify which circuits act as launch points, which regions amplify the activity and which areas limit its spread. Such information could eventually contribute to more precisely targeted treatments for epilepsy and other disorders involving abnormal brain excitability.

Peter Kner, a professor in the University of Georgia’s College of Engineering and the study’s corresponding author, emphasized the limitations of relying on two-dimensional images to understand a three-dimensional brain. A single optical plane may show a wave of activity moving across the field of view, but it cannot establish whether the wave continues outside that plane or whether apparently separate signals are connected at another depth. Volumetric imaging reduces that uncertainty by allowing researchers to track activity across the full thickness of the brain. The added dimension can reveal pathways, timing relationships and patterns of recruitment that might otherwise be mistaken for isolated events.

The microscope could also become useful beyond seizure research. High-speed, low-background light-sheet imaging is suited to observing many fast biological processes, including the development of neural circuits, the movement of immune cells and changes in blood flow. Adaptive optics may allow researchers to examine these events more sharply in thicker or more optically complex tissues. For neuroscience, the combination could help connect cellular activity with behavior by showing how neural networks operate while an organism responds to its surroundings. Although findings from zebrafish cannot be transferred directly to human patients, the model offers a practical way to test biological mechanisms and potential therapies before they are studied in more complex systems.

The study, published in Biomedical Optics Express, demonstrates how advances in optical engineering can change the questions researchers are able to ask about the brain. The work was co-authored by Bingxi Liu, Yang Liu, Carly Duffy and James Lauderdale, and was supported by the National Institutes of Health. By recording a seizure as a rapidly evolving three-dimensional event rather than as a signal on a flat screen, the researchers have brought scientists closer to understanding how pathological activity takes shape and travels through neural networks. The next challenge will be to use this detailed view to compare different seizure types, identify the mechanisms that terminate them and determine whether specific points along their route can be targeted to prevent their spread.

Subject of Research: Three-dimensional real-time imaging of seizure propagation in the zebrafish brain using adaptive optics light-sheet microscopy.

Article Title: Fast volumetric imaging of a zebrafish seizure model with adaptive optics light sheet microscopy

News Publication Date: 21 July 2026

Web References: Biomedical Optics Express article; Peter Kner, University of Georgia; James Lauderdale, University of Georgia

References: Biomedical Optics Express, DOI: 10.1364/BOE.596096

Image Credits: UGA

Keywords

Seizures, epilepsy research, zebrafish neuroscience, brain imaging, light-sheet microscopy, adaptive optics, volumetric imaging, seizure propagation, biomedical engineering, neural activity

The scientific focus of the consortium pivots on the hypothalamus, a central brain structure integral to homeostasis, behavioral regulation, and endocrine function. Prior research has recognized the hypothalamus’s role in regulating innate behaviors, including feeding, mating, defensive responses, and social interactions. However, the pathway-specific molecular and circuit-based mechanisms remain largely enigmatic. By leveraging advanced neuroimaging technologies capable of super high-resolution brain scans, Dr. Xu and his colleagues intend to visualize dynamic brain activity in humans harboring specific genetic mutations affecting hypothalamic pathways. These mutations have been implicated in a spectrum of behavioral anomalies in children, from hyperphagia and obesity to manifestations of autism spectrum disorders, aggression, and severe anxiety.

Dr. Xu’s recent appointment as the director of USF Health’s newly inaugurated Center for Molecular Psychiatry, complemented by his professorship in Psychiatry and Behavioral Neurosciences, positions him uniquely at the nexus of translational neuroscience, genetics, and metabolic research. His prior work, notably funded by the U.S. National Institutes of Health, emphasized the complex interplay between metabolic disorders such as obesity and diabetes and neurobiological dysfunctions. The current ERC-funded project builds naturally upon this foundation, linking metabolic phenotypes with neurogenetic substrates driving instinctual behavioral patterns.

The ERC Synergy Grant mechanism is designed to support exceptionally ambitious and collaborative projects that transcend single laboratories’ capabilities. The award to the INSTINCT consortium is a testament to the exceptional scientific merit and innovative potential of their proposal. Less than 10% of proposals received funding, highlighting the fiercely competitive nature of this program. The team’s integrative approach, combining human genomic data, state-of-the-art neuroimaging, and comparative behavioral studies in animal models within naturalistic social environments, promises unparalleled insights into the neural architecture governing innate behaviors.

Dr. Sadaf Farooqi’s extensive expertise in human genetics of obesity complements the team’s capacity to translate clinical genomic data into mechanistic understanding. Her prior studies have identified numerous genetic mutations that lead to severe and early-onset obesity in pediatric cohorts. By characterizing these mutations’ impact on hypothalamic circuits, the consortium aims to uncover causal pathways by which genetic aberrations precipitate complex behavioral and metabolic phenotypes. Such cross-disciplinary insights could pave the way for novel therapeutic strategies addressing multifactorial disorders rooted in neurogenetic dysfunction.

Similarly, Dr. Tiago Branco’s work at the Sainsbury Wellcome Centre brings to the table a sophisticated understanding of neural circuits and behavioral neuroscience. His research utilizes cutting-edge techniques to dissect neural substrates underlying behaviors in animal models, providing the consortium with a powerful framework to bridge findings from animal systems to human clinical contexts. This triangulation between genetics, neuroimaging, and ethologically valid behavioral assays could redefine our comprehension of how biological factors shape behavior, a longstanding question at the heart of the nature versus nurture debate.

Crucially, the project emphasizes the biological basis of behaviors traditionally viewed as voluntary or learned in humans—such as eating habits, social engagement, and emotional responses. The consortium challenges the prevailing notion that behaviors like aggression or anxiety are entirely under volitional control, instead proposing that these behaviors are deeply rooted in genetically wired brain pathways. The research aims to map how perturbations in hypothalamic function disrupt behavioral homeostasis, thereby contributing to neuropsychiatric disorders and metabolic disease comorbidities.

The methodological innovation central to the consortium’s work includes deploying super-resolution imaging to visualize hypothalamic activity patterns in vivo during various states such as hunger, satiety, and stress exposure. These data will be integrated with genetic profiles and behavioral phenotyping to construct a multidimensional model of instinctive behavior regulation. Furthermore, parallel studies on animals interacting in natural social milieus will shed light on how similar genetic alterations influence behavior in ecological contexts, thereby providing a powerful cross-species perspective.

The consortium’s journey culminated recently in Brussels, where the team underwent an intensive final round of review comprising a detailed presentation of their research program. To their delight and testament to the strength of their collaborative vision, they secured funding amidst a field of formidable competitors. Dr. Xu described the moment as both unexpected and exhilarating, underscoring the transformative potential this support offers for their inquiry into the neural control of innate behaviors.

The implications of this research extend far beyond basic science. By elucidating the neural circuitry and genetic factors driving instinctive behaviors, the team’s findings are poised to influence clinical approaches to a range of complex disorders, including obesity, anxiety disorders, autism spectrum conditions, and other neurodevelopmental abnormalities. This project represents a bold stride towards understanding human behavior’s biological roots, challenging existing paradigms, and offering hope for targeted interventions that address the underlying neurogenetic causes rather than solely managing symptoms.

As Dr. Charles J. Lockwood, executive vice president of USF Health, highlighted, this milestone reflects the increasing global visibility and impact of USF’s research enterprise. The synergy of international expertise embodied by the INSTINCT consortium demonstrates the profound value of collaborative science in tackling some of the most intricate and pressing questions in neurobiology and behavior. Dr. Xu’s gratitude for the institutional support from USF Health leadership speaks to the importance of fostering environments that enable rapid scientific progress.

Looking ahead, the INSTINCT consortium’s program promises to catalyze a paradigm shift in understanding the brain’s orchestration of behavior. Their multifaceted approach, encompassing genetics, neuroimaging, and ethological analyses, sets a new standard for integrative neuroscience research. The knowledge generated will illuminate the fundamental biological architectures that govern instinctive actions, enhancing our ability to decode human and animal behavior in health and disease with unprecedented precision.

Subject of Research:
The neurobiological and genetic mechanisms underlying instinctive behaviors, with a focus on hypothalamic pathways impacting obesity, autism, anxiety, and metabolism.

Article Title:
International Consortium Secures €10M ERC Grant to Decode the Neural Circuits of Instinctive Behavior

News Publication Date:
November 6, 2025

Web References:
https://healthscholars.usf.edu/center-for-molecular-psychiatry

References:
European Research Council Synergy Grant Program Documentation

Image Credits:
USF Health

Keywords:
Research funding, Genetic disorders, Obesity, Autism, Hypothalamus