Mapping Neuronal Connectivity Using Stochastic Optical Reconstruction Microscopy (Storm): The Brainstorm Project

Abstract

The human brain is a highly sophisticated circuit consisting of hundreds of billions of neurons that are interconnected by an even larger number of synapses. This dense network of neurons and their connections holds key information to understanding normal brain function and perhaps what underlies its disorders. Obtaining a physical map of the brain's connectivity, however, is highly challenging due to the small size and high density of neuronal processes within a given volume. Therefore, in order to generate a map of neuronal connectivity a technique that can provide high spatial resolution and molecular specificity is needed.We are using 3D multi-color stochastic optical reconstruction microscopy (STORM) in order to trace neuronal networks in culture at high spatial resolution. In order to capture an entire network of connections, we are using an automated, motorized piezo stage to image large areas in x-y (≥ 120x120 μm) as well as in z (≥ 2 μm). With this technique we can not only outline neuronal morphology at 30 μm lateral and 50 μm axial resolution, but we can also image synaptic content with high molecular specificity and identify synaptic connections. These techniques will be greatly useful for generating connectional maps of neurons in the mammalian brain and help obtain a physical understanding behind brain function.