The relationship between smooth and saccadic components in smooth pursuit.

Eye movements in smooth and pathological (saccadic and ataxic) pursuit patterns were separated by the use of the inverse fast Fourier transform. Results showed that the smooth component was significantly smaller while the saccadic component was significantly greater in the pathological pursuit patterns than in the smooth pursuit pattern. In addition, the smooth and saccadic components showed a linear relationship. These findings give some support to the threshold theory in explaining the relationship between smooth pursuit and saccades.