Anticipatory saccades during smooth pursuit eye movements and familial transmission of schizophrenia.
BACKGROUND
Smooth pursuit eye movement (SPEM) abnormalities are a putative marker of genetic risk for schizophrenia. Accurate SPEM performance requires the subject to activate neural systems responsible for smooth pursuit tracking, while simultaneously suppressing activity of neurons responsible for saccadic movements that would move the eye ahead of the target. This study examined whether specific aspects of SPEM dysfunction cosegregate with genetic risk in parents of schizophrenic probands.


METHODS
Eighteen probands and their parents had SPEM recorded. Parents with an ancestral history of schizophrenia were hypothesized to be more likely than their spouses without such a history to carry a genetic risk for schizophrenia.


RESULTS
Ten families had a single parent with a positive ancestral history for schizophrenia. The frequency of anticipatory saccades, which were mostly small, and the fraction of total eye movement that they represented were the only measures that differentiated the more likely genetic carrier parents in these families from their spouses and age-matched normals.


CONCLUSIONS
Failure to suppress saccadic anticipation of target motion during smooth pursuit appears an aspect of SPEM dysfunction related to presumed genetic risk for schizophrenia.
Ross
R G
RG
University of Colorado Health Sciences Center, Denver 80262, USA.
Olincy
A
A
Harris
J G
JG
Radant
A
A
Adler
L E
LE
Freedman
R
R
D000328:Adult; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D008297:Male; D010375:Pedigree; D011597:Psychomotor Performance / Q000502:physiology; D011698:Pursuit, Smooth / Q000502:physiology*; D012307:Risk Factors; D012438:Saccades / Q000502:physiology*; D012559:Schizophrenia / Q000235:genetics*; D012565:Schizophrenic Psychology
D005819:Genetic Markers