Recording of Visual Evoked Potentials via the Skull Electrodes in a Rat Model

Begin with an anesthetized, dark-adapted rat. Add a drug solution to the eyes to widen the pupils.

This allows more light to reach the retina, the light-sensitive layer with photoreceptors.

Make a skull incision to expose pre-implanted recording screw electrodes in the brain's visual cortex and a reference electrode at the midline.

Connect one of the visual cortex screw electrodes and the reference electrode to an amplifier for signal recording.

Next, insert a ground electrode into the tail to reduce electrical noise.

Position a light-stimulation device over the eye on the side opposite to the connected cortex screw electrode and then deliver the light flashes.

Retinal photoreceptors detect the light and convert it into electrical signals that travel along the optic nerve and transmit to the opposite visual cortex.

In the visual cortex, the pre-implanted electrode detects these signals and produces the electrical output generated by light stimuli, termed as visual evoked potentials, or VEPs.