Vestibular ocular reflex (VOR) in caspase-3 deficient mice. VOR in darkness. Gain (A) and phase (B) at different frequencies were compared among all genotypes. Negligible VOR responses were recorded for Casp3-/-mice at all stimulus conditions. Heterozygous Casp3+/-mice performed at an intermediate level compared to wild type Casp3+/+mice, with VOR impairment at higher frequencies. (C) VOR linearity at 0.2Hz. The sensitivity (increase in SPV for increase in head velocity) was reduced for the heterozygous Casp3+/-group, and negligible for the knockout Casp3-/-group. Black circle, Casp3+/+. Gray circle, Casp3+/-. Red circle, Casp3-/-. SPV, slow phase velocity.