Genetic contribution to individual variation in binocular rivalry rate.
Binocular rivalry occurs when conflicting images are presented in corresponding locations of the two eyes. Perception alternates between the images at a rate that is relatively stable within individuals but that varies widely between individuals. The determinants of this variation are unknown. In addition, slow binocular rivalry has been demonstrated in bipolar disorder, a psychiatric condition with high heritability. The present study therefore examined whether there is a genetic contribution to individual variation in binocular rivalry rate. We employed the twin method and studied both monozygotic (MZ) twins (n = 128 pairs) who are genetically identical, and dizygotic (DZ) twins (n = 220 pairs) who share roughly half their genes. MZ and DZ twin correlations for binocular rivalry rate were 0.51 and 0.19, respectively. The best-fitting genetic model showed 52% of the variance in binocular rivalry rate was accounted for by additive genetic factors. In contrast, nonshared environmental influences accounted for 18% of the variance, with the remainder attributed to measurement error. This study therefore demonstrates a substantial genetic contribution to individual variation in binocular rivalry rate. The results support the vigorous pursuit of genetic and molecular studies of binocular rivalry and further characterization of slow binocular rivalry as an endophenotype for bipolar disorder.
Perceptual and Clinical Neuroscience Group and Monash Alfred Psychiatry Research Centre, School of Psychology & Psychiatry, Monash University, Melbourne, Victoria 3145, Australia. steven.miller@med.monash.edu.au
Steven M
SM
Miller
Narelle K
NK
Hansell
Trung T
TT
Ngo
Guang B
GB
Liu
John D
JD
Pettigrew
Nicholas G
NG
Martin
Margaret J
MJ
Wright
D000293:Adolescent; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008957:Models, Genetic; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D015357:Vision Disparity / Q000235:genetics*; D015348:Vision, Binocular / Q000235:genetics*; D014796:Visual Perception / Q000235:genetics*