Measurement of eye orientation of monkeys during visual discrimination

This paper describes apparatus and procedures for measuring eye orientation in the rhesus monkey without restraining the head. The main components of the apparatus are (a) a helmet on which are mounted the discriminative stimuli and the optical and other devices for obtaining a corneal reflection, (bj a special restraining chair that allows the monkey to respond to pushbuttons in front of him, yet prevents him from reaching the equipment mounted on the helmet, and (c) systems for presenting stimuli, monitoring choice responses, and recording eye orientation, which are controlled by a LINC-8 computer. The initial findings on eye orientation during performance on both a hard and an easy brightness discrimination problem are also presented.