Meeting Reports: FENS-CHEN – NeuroLeman Summer School in Geneva

FENS-CHEN-From September 1st to 5th, 2025, the University of Geneva hosted the FENS–Chen Institute–NeuroLéman Summer School, dedicated to the theme “Neurobiology of Psychiatric Disorders.” This edition of the summer school was made possible through the generous support of the Tianqiao & Chrissy Chen In-stitute, which enabled broad participation and ensured the success of this enriching scientific event. Orga-nized by Camilla Bellone, Alan Carleton, and Christian Lüscher, the event gathered young neuroscientists and renowned experts from around the world to exchange ideas and explore advances in understanding psychiatric conditions. The five-day program provided an interdisciplinary overview of major psychiatric disorders, including schizophrenia, autism spectrum disorder (ASD), and depression, approached through clinical, pre-clinical, and computational perspectives. Lectures delivered by invited speakers covered both fundamental principles and the most recent research findings, from molecular mechanisms and circuit-level alterations to clinical outcomes and therapeutic strategies. In addition, participants were introduced to diverse methodologies, ranging from in vivo and in vitro models to computational tools and applications of artificial intelligence in psychiatry. A distinctive feature of the school was the diversity of its participants, which included clinicians, basic science researchers, and computational neuroscientists. This heterogeneity fostered fruitful discussions and encouraged integration across disciplines, reinforcing the collective goal of better understanding psychiatric disorders and identifying new avenues for treatment. Beyond its scientific value, the summer school also offered well-organized networking opportunities in an informal setting. Shared meals, local cultural experiences, and the chance to enjoy Geneva’s landscapes created an inspiring atmosphere for meaningful exchanges among participants.

Highlights of particularly exciting talks and findings:

1. Camilla Bellone provided a compelling overview of animal models of autism spectrum disorder (ASD), with particular focus on social behavior as a rewarding process. She highlighted the variety of behavioral assays available to study sociability, moving beyond quantitative measures such as time spent in social interaction to also address qualitative features, including reduced approach, disorganized exchanges, or socially inappropriate behaviors. This broader perspective offered a nu-anced understanding of how social deficits manifest differently across psychiatric disorders. Profes-sor Bellone also emphasized dopaminergic regulation as a central mechanism underlying sociabil-ity, demonstrating through fiber photometry and chemogenetics that adequate social behavior de-pends not on global changes in dopamine release, but on its precise, temporally coordinated modu-lation. Her group further dissected the neural circuits involved, underscoring the role of the Superi-or Colliculus–Ventral Tegmental Area (SC–VTA) pathway in orienting behaviors, and introduced ad-vanced machine-learning tools such as LISBET for unbiased analysis of complex social interactions.

2. Marie Schaer enriched the program with insights from clinical research in ASD. Her lecture high-lighted the use of magnetic resonance imaging (MRI) and computational modeling to unravel neural mechanisms of the disorder, with direct implications for early diagnosis and intervention. In collab-oration with Bellone, she presented the Social Motivation Hypothesis, proposing that reduced social interest leads to diminished social experiences and, ultimately, impaired cognitive development. Remarkably, her group developed a non-sedated MRI protocol for children, enabling longitudinal data collection. Their findings revealed circuit alterations in autistic children that closely mirror those observed in mouse models, bridging human and animal research. Schaer’s team also applied con-tinuous eye-tracking from early childhood, uncovering a progressively divergent gaze pattern in ASD, and pioneered AI-driven digital phenotyping, capable of achieving 80% diagnostic accuracy from video analysis. These advances, combined with intensive early-intervention programs showing promising outcomes, underscored the urgent need for broader access to such treatments despite financial and logistical barriers.

3. Stephan Eliez introduced a meta-framework for deep phenotyping of psychiatric disorders, inte-grating multidisciplinary tools to track developmental trajectories. He highlighted both the scientific value and the logistical challenges of conducting long-term longitudinal studies to follow participants from early life into adulthood.

4. Ileana Hanganu-Opatz discussed critical periods of cortical plasticity, emphasizing that early de-velopmental windows are crucial for circuit formation. Her findings demonstrated that hippocampal activity plays a driving, unidirectional role in shaping prefrontal cortex maturation, shedding light on mechanisms that may underlie vulnerability to psychiatric disorders.

Together, these presentations illustrated the power of integrating animal models, clinical studies, and ad-vanced technologies to deepen our understanding of psychiatric disorders and to develop innovative strat-egies for diagnosis and treatment.

Read more in the meeting report