Tilt adaptation as a feedback control process.
Adaptation to optical tilt was analyzed with time-varying input signals in the form of step, ramp, and triangular wave-form functions. Step-function transients appeared to stabilize at about 15 min, suggesting a time constant of 4-5 min. Gain decreased with input rate beyond about 1.4 degrees min-1 and with input amplitude. In all instances gain was considerably less than one. The frequency of the triangular waves was relatively faithfully reflected in the output, but the wave form was distorted by the uneven influence of clockwise over counter-clockwise inputs. A control system with output proportional to error and an exponential delay was proposed as a model of tilt adaptation. The relationship to adaptation of the vestibulo-ocular response also is discussed.
D000223:Adaptation, Psychological; D005246:Feedback; D006801:Humans; D008124:Locomotion; D009949:Orientation; D010469:Perceptual Distortion