Spinal cord samples. Hands holding a section of human spinal cord sliced and mounted for scanning electron microscopy (SEM). The individual sections have been mounted on a thin copper plate and gold plated. This is to allow the non-conducting tissue a means of conducting the beam current of the microscope away. SEM involves sweeping a beam of electrons over the surface of the object to be studied, and collecting the electrons it gives off in response. It produces sharp 3-dimensional images and allows magnifications of up to 100,000 times.