2-605-240 - © CM Dixon/Heritage Images

The electroretinagram: when a light stimulus is applied to the eye, the minute electrical potentials which result from this stimulation of the retina are picked up from a contact lens electrode placed on the cornea and amplified to produce a display on the oscilloscope. The signal is fed to a tape recorder and can be studied to reveal information on the neural processes of human vision. This photograph shows a lecturer with a graduate student in the middle of a research project in the University of Aston in Birmingham.