Neuroscience Subnetwork Seminar

October 30 at 10:00 AM in Brazil (UTC-3)

Luisa Ramirez

Johannes Gutenberg-Universität, Mainz, Germany

Title:  The structure of the world in the structure of the code: natural statistics and design principles for visual circuits

Abstract:  Animals moving through the world receive sensory inputs with rich statistical structure, and this structure is reflected in the neural activity that encodes them. Which principles explain this organization, from the activity of large neuronal populations to the properties of individual cell types? In this talk, I will address this question in visual systems, using the statistics of natural inputs as a common thread. First, I will consider the problem of modeling the joint activity of many neurons. In physics, very simple models describe systems with many degrees of freedom, but it is not clear why this success should transfer to biology. I will argue that two conditions are sufficient for learnability: the information shared between parts of a system must be subextensive, and it must be compressible. Both conditions are met by natural images and by the activity of retinal output neurons. This has a surprising implication for the retinal code: correlations between neurons are not noise to be discarded, but essential for coding. Second, I will zoom into the neurons that form these populations. From insects to vertebrates, early visual neurons exhibit a striking diversity of temporal response properties, yet the principles underlying this organization remain unclear. Using the fly visual system, where temporal filters are well characterized across identified cell types, I will show that temporal diversity supports efficient coding of natural motion, and that the optimal filter combinations map onto the architecture of motion-detection circuits. Finally, I will briefly discuss the fly connectome, and the challenges and new questions it opens for linking circuit structure to function.

Zoom meeting number: 845 4885 8354

Zoom password: polsan

Hands-on Minicourse on Fundamentals of Biological Physics

November 2 – 6, 2026 at ICTP-SAIFR, São Paulo, Brazil

Lecturers & Organizers:

• Silvina Ponce Dawson (UBA): Cell signaling

• Pablo de Castro (ICTP-SAIFR): Statistical Mechanics of Self-Propelled Organisms

• Rafael Menezes (ICTP-SAIFR): Individual Based Models in Ecology

More details and registration at https://www.ictp-saifr.org/mfbp2026/