ANTICIPATORY SACCADES DURING SMOOTH-PURSUIT EYE-MOVEMENTS AND FAMILIAL TRANSMISSION OF SCHIZOPHRENIA

Background: Smooth pursuit eve movement (SPEM) abnormalities are a put ative marker of genetic risk for schizophrenia. Accurate SPEM performa nce requires the subject to activate neural systems responsible for sm ooth pursuit tracking, while simultaneously suppressing activity of ne urons responsible for saccadic movements that would move the eye ahead of the target. This study examined whether specific aspects of SPEM d ysfunction cosegregate with generic risk in parents of schizophrenic p robands. Methods: Eighteen probands and their parents had SPEM recorde d Parents with an ancestral history of schizophrenia were hypothesized to be more likely than their spouses without such a history to carry a generic risk for schizophrenia.Results: Ten families had a single pa rent with a positive ancestral history for schizophrenia. The frequenc y of anticipatory saccades, which were mostly small, and the fraction of total eye movement that they represented were the only measures tha t differentiated the more likely genetic carrier parents in these fami lies from their spouses and age-matched normals. Conclusions: Failure to suppress saccadic anticipation of target motion during smooth pursu it appears an aspect of SPEM dysfunction related to presumed generic r isk for schizophrenia. Biol Psychiatry 1998;44:690-697 (C) 1998 Societ y of Biological Psychiatry.