A major approach in our research includes the precise stimulation of single nerve cells in living animals. This is done by expressing a lightsensitive protein in cells followed by stimulation with a laser beam. The beam needs to be focused and control in 3-dimensions. Over the last 2 years, we have added to our current 2-photon imaging microscope, a laser control system called a spatial light modulator to direct the laser beam to specific nerve cells inside the brain. We now need to improve stimulation efficacy by fast spiraling of the laser beam which cannot be achieved with current spatial light modulators. Instead, the laser beam is quickly rotated using 2 mirrors that are controlled by galvometers inside a secondary light path added to the existing microscope. This galvo-galvo pathway is microscope and imaging software specific.