Neuroscience Seminar - M. Fallah: Oculomotor Control of Visual Spatial Attention

Presenter:
Dr. Mazyar Fallah
Assistant Professor
Department of Kinesiology and Health Science
York University

Location:
York University
Behavioural Sciences Building Conference
Room 163

Abstract: Something that abruptly appears or disappears in the environment might be the hallmark of a predator to be wary of, or prey to capture for one's own benefit. When something unexpected occurs in your surroundings, selective attention is automatically oriented to the region, initiating a cascade of processing designed to determine as quickly as possible, whether it should have consequences for future behaviour. Alternatively, attention can be voluntarily directed to a location. Commonly, attention and eye movements are oriented to the same location, bringing the image of the event onto the fovea, the region of the retina with highest acuity. However, the eyes can be held at one location, while still allowing (covert) attentional allocation to a different spatial location. This can be much to the chagrin of many school children as their teacher watches them "from the corner of her eye". Although covert orienting is not be visible to the observer, the benefits of spatial attention allocation to an external event are seen behaviorally, in the form of faster or more accurate processing of visual stimuli at the attended location (Jonides, 1981; Posner et al., 1978, 1980; Posner, 1980). Valid cues result in facilitation, or a benefit in performance, at the attended location. Invalid cues result in a cost, or impaired performance, at unattended locations. Spatial attention allocation results in preferential processing of visual stimuli at the attended location in the visual field (Jonides, 1981; Posner et al., 1978, 1980; Posner, 1980) and modulates the responses of neurons in the visual system whose receptive fields coincide with the attended location in the visual field (Luck et al., 1997; Moran and Desimone, 1988; Ress et al., 2000; Reynolds et al., 1999; Spitzer et al., 1988). The focus of this talk is elucidating the mechanism that deploys spatial attention.