The Neural Correlates of Target Selection

Smith-Kettlewell Eye Research Foundation, San Francisco CA

Investigators

Abstract

When we interact with our surroundings we are often looking at or reaching for an object of interest that is embedded in the clutter of daily life. Successful interaction with our surroundings requires that several processes work in concert. These include image-related factors, such as, how the target of our reaching differs from its surroundings, visual processes that organize the scene into potential targets and background, and cognitive factors such as task demands and prior knowledge of target. With funding from the National Science Foundation, Dr. Preeti Verghese and her colleagues are investigating how all of these processes unfold over time, and how they interact to select a target on a textured background. Their research uses psychophysics, as well as high-density electroencephalography (EEG) combined with a process that localizes the cortical sources of the scalp potentials to determine the neural populations that implement these processes. The two aims address important questions about the interaction of selective attention and segmentation processes: When attention is directed to a target, how do the surrounding context and task requirements influence how efficiently the target is selected? What is the time course of this interaction: How does evidence for the target evolve over time, and how do attention and task demands influence the way in which a target is segmented from the background? This study aims to understand the neural underpinnings of target selection in the real world. As such it has relevance to activities of daily life. It is also relevant to clinical populations with people who have difficulty with target selection. These include people with damage to parts of the visual cortex due to stroke, injury, or tumors that result in a diminished awareness of objects that are represented by the affected parts of the cortex. This visual neglect is particularly acute in the presence of other objects in the visual field. Training is also a strong component of this research program. This research project provides research opportunities for high school and undergraduate students to gain exposure to science as summer interns. Because the research is multidisciplinary, postdoctoral fellows are having the opportunity to train in research areas that complement their doctoral research.