My research interest is to understand how perception and action emerge from brain activity. My main approach is to record neural activity in the brains of monkeys performing various visual search and forced-choice discrimination tasks. Most of my research has focused on the frontal eye field, which is located in the prefrontal cortex and participates in the transformation of visual information into commands to move the eyes. The goal this project is to understand how the brain decides where to direct gaze and to understand the neural basis of directed visual attention. I hypothesize that the frontal eye field functions as a topographic map that represents the relative importance of every object in the visual scene by integrating the neural representation of the visual scene with the viewer?s knowledge about the world. The resulting topographic representation corresponds to the salience map that is featured in many theoretical models of directed spatial attention and saccade target selection. If this hypothesis is correct, then the location represented by the highest activity in the frontal eye field corresponds to the spotlight of covert spatial attention and directs saccades in a probabilistic manner. In Thompson, et al. (2004) and in Sato et al. (2003) we put this theory to the test and confirm that the activity pattern across the frontal eye field forms a map of saccade probability based on the intrinsic visual salience of objects and the knowledge and expectations of the viewer. In Schall et al. (2003) we show that the receptive fields of frontal eye field neurons have a center-surround organization that reflects spatial variations in the allocation of attention. The role of the frontal eye field in visual processing and saccade generation is reviewed in Schall et al. (2003). In Thompson and Bichot (2004), we synthesize the evidence from many experiments to show that the frontal eye field is indeed a map of visual salience and not just a motor map for the generation of eye movements. In Thompson (2004) I present evidence showing that the activity in frontal eye field likely contributes to the spotlight of enhanced visual processing associated with directed visual attention without eye movements. These studies have extended our understanding about the frontal eye field far beyond its familiar role in controlling eye movements. With this knowledge we can design experiments to investigate the flow of sensory information through the brain as it is transformed into perception and action. This work helps us understand the mechanisms of how the brain focuses attention to make perceptual decisions and guide behavior, which is necessary to be able to understand and treat attention-related disorders in humans.
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