Non-linear retinal processing supports invariance during fixational eye movements

Abstract

Fixational eye movements can rapidly shift the retinal image, but typically remain unnoticed. We identify and simulate a model mechanism for the suppression of erroneous motion signals under fixational eye movements. This mechanism exploits the non-linearities common to many classes of large retinal ganglion cells in the mammalian retina, and negates the need for extra-retinal signals or explicit gaze information. When tested using natural images undergoing simulated fixational eye movements, our model successfully distinguishes "real world" motion from retinal motion induced by eye movements. In addition, this model suggests a possible explanation for several fixational eye movement related visual illusions such as the Ouchi-Spillmann and "Out-of-focus" illusions.

Keywords: Fixational eye movement; Gaze-invariance; Invariance; Motion; Ouchi illusion; Parasol; Retinal ganglion cell; Stabilisation; Y cell.