Microscopy mash-up quantifies, maps neural circuits

By melding two microscopy methods and a computational tool, researchers can quickly and precisely quantify neuronal connections in individual animals, according to a new study. The technique could make it faster to map the connectomes of autism mouse models and track how mutations in autism-associated genes rewire neural circuits. A human neuron has thousands of synaptic connections, which light-based microscopy lacks the resolution to detect. Electron microscopy can resolve neuronal links in exquisite detail -- theoretically down to 0.12 nanometers, a length slightly shorter than a carbon-carbon chemical bond -- but the process is slow and laborious. In one study, it took about three years to section and image a single fly brain with a scanning electron microscope.