Multiphoton imaging can be used to image deep inside scattering tissue and can thus be used to image neural activity and structural dynamics in intact neural tissue and even in the intact brain. Amplified femtosecond pulses can be used to improve the depth penetration and adaptive optics can help to improve resolution and signal size. To image entire cellular geometry of neurons electron microscopic resolution is necessary. Serial block-face electron microscopy can produce well aligned, distortion-free 3D images set that allow to tracing of neural wires with the ultimate goal of reconstructing the detailed circuit diagram of the brain.