Features for quantifying eye movements under infrared illumination. (A) Plot of changes in eye angle of a single eye over time. (B) Amplitude spectra of the continuous waveform in (A) as a function of frequency. A peak at 0.25 Hz corresponded to the rotation period of 4 seconds as shown in (A). In this case, the largest value of angle change observed was about 7 degree. (C) Normalized eye movements derived from changes in the total area (red line) or the long and short axis ratio (blue dashed line) of a single eye. (D) Amplitude spectra of (C). The fraction change at 0.25 Hz is indicated in the brackets. Note that the eye ratio change yielded higher peaks at 0.25 Hz than changes in total eye area in both time domain (C) and spectral (D) plots.
Mo et al. BMC Neuroscience 2010 11:110 doi:10.1186/1471-2202-11-110