Smooth pursuit is usually studied with small, spot stimuli, yet extended natural objects stimulate peripheral retina and have features of interest. It is unknown how peripheral motion interacts with pursuit, or how attention is allocated to features during it. We have evidence that peripheral motion improves pursuit by minimizing saccades, and that attention is not locked to the fovea, but can be allocated flexibly to the periphery when the foveal pursuit burden is reduced. Furthermore, pilot data show that merely diverting attention from the fovea improves pursuit. It follows that a motion system incorporating peripheral retina can drive ocular pursuit more smoothly and allow an attentive process to simultaneously monitor local motion features, and our pilot data support this hypothesis. In addition we find that attentional resources for these pursuit and feature monitoring systems appear to be separate.
Specific Aims are:
Aim 1) Is attention allocation during pursuit flexible? Experiments will assess attention allocation under conditions that manipulate foveal attention demands while controlling for low-level features such as luminance transients.
Aim 2) Does foveal attention increase saccades during pursuit? Experiments in this aim measure pursuit and manipulate attention and the locus of retinal stimulation.
Aim 3) Do multi-element stimuli simultaneously support independent eye and attention movements? Experiments investigate whether attentional resources for pursuit and feature tracking are independent using attention operating characteristic (AOC) analysis. Other experiments will determine if only the attended elements are pursued, and if they are, if attention still arises from two sources.
Our project has relevance to Age-Related Maculopathy (ARM), an eye disease that can result in permanent damage of the central retina, since it addresses foveal as well as peripheral contributions to pursuit. It is widely accepted that ARM is the leading cause of severe visual impairment in the U.S. and in other industrialized countries. Understanding how peripheral and foveal information are processed during pursuit is key for helping patients with ARM learn to maintain clear vision of moving objects. Previous work studying pursuit with central visual loss has used small spot targets, and focused on how the spot was pursued with their new preferred retinal locus (PRL). Knowledge of peripheral and foveal contributions during pursuit could help guide oculomotor therapy on ARM patients who have lost use of their foveae.
|Jin, Zhenlan; Watamaniuk, Scott N J; Khan, Aarlenne Z et al. (2014) Motion integration for ocular pursuit does not hinder perceptual segregation of moving objects. J Neurosci 34:5835-41|