Frequency dependence of cat vestibulo-ocular reflex direction adaptation: Single frequency and multifrequency rotations

Vertical and horizontal vestibulo-ocular reflex (VOR) eye movements were recorded in alert cats during horizontal rotation in total darkness before and after a 2 h vestibulo-ocular reflex direction adaptation procedure. Adaptation stimuli were whole body horizontal vestibular rotation coupled to synchronous vertical optokinetic motion. The waveform of the adaptation stimuli was either a sinusoid at 0.05, 0.1, 0.25, 0.5 or 1 Hz, or a sum of sinusoids containing 0.2, 0.3, 0.5, 0.7, 1.1, and 1.7 Hz. Exposure to single frequency stimuli produced adaptive vertical VOR with a gain that was greatest near the training frequency; adaptive VOR phases were advanced below, accurate at, and lagged above the training frequency. Exposure to the multifrequency waveform produced a uniform modest increase in gain across frequencies, with accurate adaptive VOR phase.