June 2021
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Zoom Brown Bag: Understanding Smooth Pursuit Deficits in Macular Degeneration
Event Date:Abstract - Age-related macular degeneration (AMD) is the most prevalent cause of central visual field loss. Since the high-acuity fovea (the oculomotor locus) is often impaired in AMD, people afflicted with the condition typically have difficulties with smooth pursuit eye movements. In this brown-bag, I will detail two possible causes for deficits in smooth pursuit in AMD: 1) noisy sensory input due to objects disappearing into the scotoma, and 2) oculomotor instability due to the use of an eccentric preferred retinal locus (PRL). To address the first cause, we designed an experiment to categorize the noise introduced when the target of pursuit is hidden by the scotoma in AMD. We presented control participants with a Brownian motion display with an increased dot density region into which the target could disappear and compared pursuit during this disappearance with AMD participants. In addition to showing preliminary results, I present a plan to categorize the effects of oculomotor instability on the pursuit in AMD as well as a candidate model to integrate the two proposed causes of pursuit deficits in AMD, based on Bayesian frameworks recently used to describe predictive smooth pursuit in individuals with healthy vision. https://www.ski.org/users/jason-rubinstein
Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)
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Zoom Brown Bag: A New Model of Binocular Eye Movement Control
Event Date:Abstract - Despite that we have two eyes, dominant models of voluntary eye movement control except a single input, and issue a single conjugate command, in accordance with Hering’s Law. When midline gaze shifts are required, Hering postulated that another single command generates vergence. Many natural gaze shifts are not simply restricted to the frontoparallel plane, or the midline. Hering resolved this by postulating that conjugate and vergence commands simply sum. These “classic” theories have guided basic oculomotor research and strabismus intervention for over a century, but have recently been challenged with new data from an occluded eye (Chandna et al., 2021).
I will present a new model of binocular control that can explain occluded eye data, and can generate other human oculomotor behavior that challenges existing models. The model consists of a fast, binocular conjugate component that is modulated by slow, independent controllers on each eye. The independent controllers can use interpreted sensory information to generate eye movements even when sensory evidence is incomplete. https://www.ski.org/users/steve-heinen
Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)
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Zoom Colloquium: Eye movements as readout of predictive and decision processes
Event Date:Abstract - Visually-guided orienting eye movements (saccades and smooth pursuit) are primarily determined by the physical properties of the target stimuli. However, cognitive factors, such as expectancy and motivation can significantly modulate this kind of eye movements. For instance, past work in our group has highlighted a robust parametric relation between the expected probability of visual motion direction and anticipatory smooth eye movements. I will present recent extensions of the analysis of predictive eye movements across development and across contexts of increasing complexity. In addition, I will illustrate the dynamic relation between visually-guided eye movements and visual perceptual decisions. In particular, I will describe the recently identified dissociation between the oculomotor and the perceptual bias induced by experience-based motion expectancy. Finally, I will discuss how these findings can be conciliated with the theoretical framework of Bayesian inference for sensorimotor integration and perception.
Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)
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