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DY: Fachverband Dynamik und Statistische Physik

DY 14: Focus Session: Nonlinear Dynamics in Biological Systems I (joint session DY/BP)

DY 14.7: Hauptvortrag

Dienstag, 18. März 2025, 11:30–12:00, H43

Beyond the connectionist view: (De-)synchronizing neural networks via cell-intrinsic dynamics — •Susanne Schreiber — Humboldt-Universität zu Berlin, Institute for Theoretical Biology, Berlin, Germany

Neural computation is thought to arise from the connectivity among neurons. Accordingly, we are often more than happy to ignore seemingly unimportant and potentially overwhelming biological detail, for example, related to the properties of the neurons themselves. In this talk, however, I will highlight how cell-intrinsic dynamics, namely the biophysics of action-potential generation, can have a decisive impact on network behaviour. Recent work of my lab shows that, among regularly firing neurons, the somewhat unattended homoclinic type (characterized by a spike onset via a saddle homoclinic orbit bifurcation) particularly stands out: First, spikes of this type foster specific network states - synchronisation in inhibitory and splayed-out/frustrated states in excitatory networks. Second, homoclinic spikes can be easily induced in by changes in a variety of physiological parameters (like temperature, extracellular potassium, or dendritic morphology). As a consequence, small changes in these parameters can suffice to induce drastic switches in network states. I will discuss functional consequences of homoclinic spikes for the design of pattern-generating motor circuits in Drosophila as well as for mammalian pathologies like febrile seizures. Our work predicts an interesting role for homoclinic action potentials as an integral part of brain dynamics in both health and disease.

Keywords: network synchronization; nonlinear dynamics; spike onset bifurcation; biophysical parameters; neural computation