Seminar: Ultrastructural readout of in vivo synaptic activity for functional connectomics by Dr Arnd Roth, UCL

Title: "Ultrastructural readout of in vivo synaptic activity for functional connectomics"

Speaker: Dr Arnd Roth (UCL)

Abstract:

Large-volume ultrastructural mapping approaches yield detailed circuit wiring diagrams but lack integrated synaptic activity readouts that are essential for functional interpretation of connectomes. Here we resolve this limitation, combining labeling of active synapses in vivo with focused ion-beam scanning electron microscopy (FIBSEM) and machine learning-based segmentation. Our approach generates high-resolution three-dimensional readouts of activated vesicle pools across large populations of individual synapses in tissue volumes. We apply this method to study synapses activated by sensory input in primary visual cortex in awake head-fixed mice, establishing ultrastructural predictors of synaptic activity, the lognormal distributions of functional pool size and release probability, and fundamental organizational principles of functional pool classes. Our approach will open the way for detailed functional connectomics studies, enabling predictions of synaptic activity and weight to be directly overlaid onto wiring diagrams.

https://www.biorxiv.org/content/10.1101/2021.07.07.451278v1.full

Bio:

Arnd Roth studied physics at the University of Heidelberg, Germany, and did his PhD with Bert Sakmann at the Max Planck Institute for Medical Research. Currently he is a Senior Research Fellow at the Wolfson Institute for Biomedical Research at University College London. His research interests include models of the anatomy and function of neural circuits in the neocortex and cerebellum, models of synaptic integration in dendrites in vivo, and the role of single neurons in neural computation. He is particularly interested in linking new types of anatomical, electrophysiological and imaging data via detailed models to more abstract theories of information processing in the brain.

This seminar is organized by Computational Neuroscience Unit(De Schutter Unit).