Real time pxi computer

After overnight dark adaptation, mice were anesthetized under dim red illumination with 0.1 mg/kg ketamine and 10 mg/kg xylazine. Under anesthesia, both eyes were treated with 0.5% proparacaine followed by a mixture of 2.5% phenylephrine and 1% tropicamide for pupil dilation. The mice were kept warm using a 37°C heating pad (Deltaphase Isothermal Pads; Braintree Scientific). A gold reference electrode was electrically connected to the cornea of one eye and a platinum wire, mounted on a fiber-optic cable, was connected to the cornea of the other eye. Electrical continuity was made using hydroxypropyl methylcellulose (Goniosol). Light stimuli were delivered directly into the eye through the tip of the fiber optic. Stimulus intensity was controlled by calibrated neutral density filters, and stimulus wavelength was 500 nm (±5 nm; narrow band filter) or 505 nm (±17 nm; broad band filter). Responses were recorded from threshold up to light 1,000,000 fold brighter in darkness, and the photopic responses were recorded in the presence of rod-saturating background lights. Electrical responses were amplified (Astro-med CP122W; DC-300Hz) and digitized at 2 KHz (Real-Time PXI Computer; National Instruments).