In Vivo Intracellular Recording of Photoreceptor Cell Spectral Sensitivity in a Butterfly

Begin with an immobilized butterfly on a platform.

Under a dissecting microscope, insert a reference electrode through the mouthparts to reach the head, and fix the electrode to the platform.

Make a small incision in the cornea and seal it to prevent drying.

Using brief lighting under a stereoscope, position a recording electrode filled with an ionic solution above the cornea.

Then, lower the electrode into the cornea using a micromanipulator to access the photoreceptor cell.

A significant voltage change across the membrane indicates the contact of the electrode with the cell.

Dark-adapt the insect by switching off the external light sources.

Initiate light flashes with a pulse generator and direct a fiber optic cable toward the eye.

Adjust the position of the electrode and fiber optic cable until a depolarizing response is obtained.

Record the cell's responses to white light and colored filters to assess its sensitivity to different light wavelengths.