A, B, Images of the device used to fix the skull of a mouse while recording awake ERGs and VEPs. C, Experimental setup for recording. A mouse with head fixed to the restraint device was placed on a rotatable polystyrene cylinder. The setup allows the mouse to run or walk freely during ERG/VEP recording. Electrical cords, which are not shown in the image, were connected to the electrodes on the skull during recording. D, An adaptor, a nut, and a bolt used to connect a mouse to the vertical attachment of the restraint device (red arrows in panels A, B, and C). The ends of the adaptor linked the mouse skull to the restraint device and platform. E, Screw electrode, fixation bolt, and wire electrode implants: 1, reference wire electrode for ERG; 2, reference screw electrode for VEP; 3, 4, positive screw electrodes for VEP; 5, plastic bolt used to attach the skull to the fixation device (see blue arrows in panels C and E); asterisk, bregma.