2-Photon microscopy has opened a rapidly expanding field of imaging studies in intact tissues and living animals. Diverse lymphatic organs, kidney, heart, skin, and brain can be examined. 2-Photon microscopy enables studies about intact nervous systems and investigation of growth cone dynamics.

Tracking and quantification of neuronal filopodia dynamics in 3D 2-photon microscopy

Filopodia dynamics are thought to control growth cone guidance during brain wiring, but the types and roles of growth cone dynamics underlying neuronal circuit assembly in a living brain are largely unknown. To address this issue, a brain culture live-image system that is applicable for all developmental stages of Drosophila brain was developed. The used 2-photon microscope allows generating 3D time series of R7 growth cones of different age, genetic manipulation, or chemical treatment. To analyze and compare the filopodia dynamics in the acquired datasets of different types, an efficient method for information extraction and quantification is required. We developed a semi-automatic pipeline in the 3D Software Amira that allows 3D reconstruction and tracking of filopodia represented as skeleton graphs. Those graphs simplify the extraction of statistical information like filopodial length, number, orientation, retraction, and extensions.


Analysis of Vesicle Trafficking in Axons

The dynamics of transport vesicles during neural development are still unknown. Vesicles can transport proteins and metabolic substances from the soma to the axon terminal and back. We track and analyze vesicles in time-lapse 2-photon microscopy by building Markov sate models based on trajectories. The stationary distribution and committor probabilities along the axon clearly indicate retrogade transport. 


Serial synapse formation through filopodial competition for synaptic seeding factors Developmental Cell, 50(4), pp. 447-461, 2019 (preprint available as ZIB-Report 19-45) Mehmet Neset Ozel, Abhishek Kulkarni, Amr Hasan, Josephine Brummer, Marian Moldenhauer, Ilsa-Maria Daumann, Heike Wolfenberg, Vincent J. Dercksen, Ferdi Ridvan Kiral, Martin Weiser, Steffen Prohaska, Max von Kleist, Peter Robin Hiesinger PDF (ZIB-Report)
Analysis of Growth Cone Dynamics
Live Observation of Two Parallel Membrane Degradation Pathways at Axon Terminals Current Biology, 28(7), pp. 1027-1038.e4, 2018 Eugene Jennifer Jin, Ferdi Ridvan Kiral, Mehmet Neset Ozel, Lara Sophie Burchardt, Marc Osterland, Daniel Epstein, Heike Wolfenberg, Steffen Prohaska, Peter Robin Hiesinger BibTeX
Analysis of Growth Cone Dynamics