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Jeffrey B. Mulligan, Scott B. Stevenson, Lawrence K. Cormack; Polarization analysis of the eye movement correlogram. Journal of Vision 2004;4(8):651. doi: https://doi.org/10.1167/4.8.651.
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© ARVO (1962-2015); The Authors (2016-present)
The eye movement correlogram is obtained by reverse correlation of eye velocity with the velocity of a randomly moving target. It resembles an impulse response, typically peaking at a latency between 100 and 200 milliseconds. The target can move randomly in two dimensions, and the analysis may be performed independently on the horizontal and vertical components. Striking differences are seen in the correlograms obtained in these two directions, which might arise in motor pathways, sensory pathways, or both. More detail can be gleaned about these differences from a “polarization” analysis. Instead of performing the analysis simply on the nominal horizontal and vertical axes, individual correlograms are computed for a densely sampled array of stimulus and measurement directions. The resulting set of signals is well-described by a linear superposition of two mechanisms having different time courses, and the geometric relation between the mechanisms can be estimated. We have used this method to probe how the visual system analyzes the motion of different types of stimuli by comparing the responses obtained while tracking a small spot to those obtained while tracking gratings and two-component plaids. The results for plaids cannot be simply described as the superposition of the responses to the component gratings, reflecting the fact that voluntary pursuit is controlled by the output of a high-level “pattern motion” stage. However, different responses are obtained for different plaids, reflecting biases in the computation of pattern motion.
The Airspace Operations Systems (AOS) project of NASA's Airspace Systems program; R01-EY12986.
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