Heritability of spontaneous eye blink rate

Spontaneous eye blink rate (EBR) is a simple involuntary behavior that can be measured unobtrusively in a variety of settings. EBR shows substantial inter-individual variability and has been associated with differences in... [ view full abstract ]

Spontaneous eye blink rate (EBR) is a simple involuntary behavior that can be measured unobtrusively in a variety of settings. EBR shows substantial inter-individual variability and has been associated with differences in cognitive function, personality, and psychopathology. Increasing evidence suggests that EBR can serve as an indirect indicator of central dopamine function. However, little is known about the extent to what individual differences in EBR are influenced by genetic factors. Here we investigated heritability of EBR in a population-based sample of young adult twins. Eye blinks were detected using an electro-oculographic (EOG) recording in a resting-state condition while the subjects were instructed to keep their gaze on a fixation cross. Four 1-min resting periods were sampled during a two-hour laboratory session, and individual EBR was computed as the average number of blinks per minute. Linear structural equation modeling of twin data showed that 55% of EBR variance can be attributed to additive genetic factors, with little evidence for shared environmental influences.