Kinematic features in mouse OKR evoked by 1 s constant-velocity stimulation. A, A part of a raw eye-position trace (top black trace). The mouse was kept in the dark, and visual stimuli were presented by illuminating an optokinetic drum for 1 s (vertical yellow bars). The drum rotated at a constant velocity (30°/s), with alternate changes in direction (bottom blue trace). Gray parts in the eye-position trace contain saccades and erroneous eye-tracking periods (see Material and Methods) that were excluded from the average position and velocity traces shown in B. Positive and negative values in eye position correspond to temporal (T) and nasal (N) eye position, respectively. Eye position of 0° is resting eye position. Positive and negative values in velocity correspond to movements toward the N–T and T–N directions, respectively. All the position and velocity traces in this paper follow this convention. Visual stimuli were binocularly presented in all the experiments in this paper. B, Average eye-position and eye-velocity traces from the data shown in A. The yellow bar indicates the visual stimulation (±30°/s). C, Average of average eye-position (left) and eye-velocity traces (right) from seven animals. Different line colors indicate stimulation velocities (purple, 5°/s; blue, 15°/s; green, 30°/s; yellow, 60°/s; red, 90°/s), which are also shown as numbers to the right of the eye-position traces. Dotted lines indicate zero line. Gray envelop of each trace is SEM. D, Close-up of the OKR onset in the average eye-position trace shown in C, indicating slower onset at stimulation of 5°/s. E–G, I–K, Onset latency (E), eye velocity 0.2 s after the stimulation onset (F), eye-velocity change from 0.2 to 1 s after the stimulation onset (G), deceleration τ (I, J), and rebounding gaze drift (K) are plotted as a function of stimulation velocity (all but J) or stimulation duration (J). Triangles and inverted triangles indicate measurements from the N–T and T–N OKRs, respectively. The colors of the symbols correspond to stimulation velocities as in C. H, Eye-position trace showing the OKR (optokinetic nystagmus) evoked by a prolonged constant-velocity stimulation (30°/s for 20 s). The nystagmus almost ceased in the last half of the stimulation. Error bars, SEM.