The optical tomography of a whole thy1-GFP-M mouse brain (total volume ≈223 mm3) was acquired using confocal light sheet micrscopy. From the three-dimensional reconstruction of the whole brain we virtually dissected volumes from the hippocampus and the superior colliculus. In both cases, isolated neuronal processes can be clearly distinguished, demonstrating the possibility of studying long-range projections tracing several neurites over a mm-sized volume in a core region of the brain. For clarity, each neuron was drawn with a different color. Scale bars, 200 μm. For details, see Silvestri et al., Opt. Express 20, 20582 (2012).