Spatiotemporal dynamics of the neuronal cytoskeleton across scales during development

Neuronal structure is intrinsically tied to neuronal function because the spatial arrangement of the output (axon) and inputs (dendrites) of a neuron determines how it integrates into the neuronal network. A critical component of the cytoskeleton that drives neuronal morphology is actin, which is necessary for establishing connections (synapses) early in development to refining connections as networks mature. Using live confocal imaging, we study how the dynamics of actin change as cultures of in vitro primary rat cortical neurons develop. We employ two-dimensional Laplacian of Gaussian (LoG) filtering to identify neuronal processes and a pixel-based optical flow algorithm to track actin dynamics in developing neurons. We observe micron-scale actin dynamics in younger neurons (1-5 days in vitro) that clearly drive the pathfinding of growth cones, whereas older neurons display actin dynamics on a much smaller scale, confined to small regions of dendrites and to synaptic spines. Future work will further characterize these dynamics at key developmental timepoints.