BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Poking Brains: the Mechanics of Neural Development - Amelia Joy Th ompson DTSTART:20150308T163000Z DTEND:20150308T170000Z UID:TALK58322@talks.cam.ac.uk CONTACT:George Fortune DESCRIPTION:Neuronal growth is essential for nervous system development an d is also required for regeneration after nervous tissue injury. As axons and dendrites grow towards their targets\, they are guided by environmenta l cues\, including a well-characterised set of biochemical signals. Recent in vitro studies suggest that neuronal growth can also be regulated by me chanical properties of the substrate. However\, the role of mechanical cue s in axon pathfinding in vivo\, and the spatiotemporal dynamics of tissue mechanics during early nervous system development\, are still largely unkn own. Here we investigate the role of tissue stiffness in axon guidance wit hin the early embryo\, using the Xenopus laevis optic tract as a model sys tem. Retinal ganglion cell (RGC) axons form the optic tract by growing fro m the embryonic retina\, along a stereotypical path on the brain surface\, and terminating at their target\, the tectum. We have developed in vivo a tomic force microscopy (AFM) to map tissue stiffness along the optic tract at different developmental stages. We find that the embryonic brain is ov erall mechanically inhomogeneous\, and that brain stiffness changes over t ime. Specifically\, we find that the elastic stiffness of the tectum is co nsistently lower than the rest of the path taken by RGCs. Our results indi cate that the path of RGCs is correlated with stiffness gradients in vivo\ , before axon growth stalls after reaching the softer region. These findin gs are consistent with a role for substrate mechanics in axon pathfinding\ , which might not only be crucial during development but also during regen erative processes in the nervous system. LOCATION:Winstanley Lecture Theatre END:VEVENT END:VCALENDAR