Using the eye-movement system to control the head

Abstract

We tested the hypothesis that A.I., a subject who has total opthalmoplegia, resulting in a lack of eye movements, used her head to orientate in a qualitatively similar way to eye–based orientating of control subjects. We used four classic eye–movement paradigms and measured A.I.'s head movements while she performed the tasks. These paradigms were (i) the gap paradigm, (ii) the remote–distractor effect, (iii) the anti–saccade paradigm, and (iv) tests of saccadic suppression. In all cases, A.I.'s head saccades were qualitatively similar to previously reported eye–movement data. We conclude that A.I.'s head movements are probably controlled by the same neural mechanisms that control eye movements in unimpaired subjects.