Soma Mizobuchi^1,2 (), Jonathan D. Victor³, Michele Rucci^1,2; ¹Department of Brain and Cognitive Sciences, University of Rochester, USA, ²Center for Visual Science, University of Rochester, USA, ³Weill Cornell Medical College, USA

Humans use rapid eye movements (saccades) to center the high-acuity fovea on objects of interest. Saccades cause the image to shift on the retina, delivering temporal transients rich in spatial information to neurons highly sensitive to input changes. Previous research has shown that the luminance modulations resulting from saccades are stereotypically structured (Mostofi et al, 2018). The strength of luminance modulations increases with the spatial frequency of the stimulus in a way that counterbalances the power spectrum of natural scenes in a low spatial frequency band (whitening regime) and remains constant at higher frequencies (saturation regime). The bandwidth of whitening critically depends on saccade amplitude, increasing for smaller saccades. Here we examine how the space-time reformatting resulting from saccades interacts with the response sensitivity of retinal ganglion cells at a population level. We modeled spatial and temporal response properties of parvocellular (P) and magnocellular (M) neurons at various eccentricity in the macaque's retina following published neurophysiological data. Modeled neurons were exposed to the visual input signals from saccades by moving their receptive fields over natural scenes following sequences of eye movements recorded from human observers. We measured the average pairwise correlation for neurons at systematically spaced distances following saccades. As expected from the spatial characteristics of cell receptive fields, broad correlations occurred in both M and P cell populations at all eccentricities when images were presented without saccades. Saccades greatly attenuated correlations. This effect was particularly pronounced for small saccades (amplitudes less than 2 degrees) which resulted in an almost complete decorrelation of natural scenes. These results indicate that luminance modulations from saccades contribute to an efficient neural code at the retinal output.

Acknowledgements: NIH EY18363, NIH EY07977 and P30 EY001319