Decomposition of saccadic pulse and step components by independent component analysis

Saccades are conjunctive and believed to be the fastest eye movements, which function to redirect the fovea of the retina to the object of interest. Main sequence relations have generally been used for describing the dynamics of the saccadic eye movements. Fourier analysis has also been used in quantitative investigation of saccades. A previous investigation used an inverse method from the Fourier transform of the padded and mirrored position profile and the impulse response of the system model to reconstruct the input signal (pulse and step) of a saccade. Recently, independent component analysis (ICA) has been used to decompose the transient and the sustained components of vergence eye movements, in which Scree test of the principal component analysis (PCA) was used to detect the number of independent components. In this study, we applied ICA for the decomposition of pulse and step components for saccades. The results show that the pulse component is far from rectangular; double-steps were also observed from the decomposed components. It was also found that the pulse component was activated before the step, which is matched with the pulse-step model proposed by Robinson. In conclusion, ICA suggests an alternate technique for the decomposition of saccadic components.