Figure 4.

The N–T and T–N OKRs are independently adaptable. A, Training stimulation for unidirectional OKR adaptation. Velocity of an optokinetic drum was sinusoidally modulated between 0 and 31.4°/s at 0.5 Hz (left bottom graph), which unidirectionally moved the drum position (left top graph). When the training stimulation is counterclockwise, the N–T OKR in the left eye and the T–N OKR in the right eye were trained by the stimulation, whereas the OKR toward the other direction was left untrained, as illustrated in the right panel. The training paradigm except for the training stimulation was the same as shown in Figure 2A. B, C, Average of average eye-position (the first and third rows) and eye-velocity (the second and fourth rows) traces of the OKRs evoked by 0.2 s constant-velocity stimulation at 30°/s (n = 8 mice). Traces were shown in the same way as in Figure 3A, B. B and C show results from the eyes that were trained by the N–T (A, left eye) and T–N (A, right eye) stimulation, respectively. D–G, Changes of peak eye velocity (D), deceleration τ (E), rebounding gaze drift (F), and onset latency (G) over the course of the adaptation training. These kinematic features were measured from the OKRs evoked by 0.2 s constant-velocity stimulation at 30°/s. Graphs are organized in the same way as Figure 3C–F. Left and right graphs show results from the eye trained by the N–T and T–N stimulation, respectively.