This Minority Post-Doctoral Research and Training Fellowship will be conducted at the University of British Columbia, in Vancouver, Canada, under the supervision of Dr. Alan Kingstone. The central topic of investigation is a phenomenon known as Troxler Fading (Troxler, 1804). Troxler Fading (TF) occurs when an observer pays attention to an object (the target) in his/her peripheral field of vision, while keeping his/her eyes focused on a secondary object. After several seconds of sustained attention, the target disappears from the observer's view for a few seconds. At its location, the observer instead perceives a smooth continuation of the background surface. This phenomenon is also known as perceptual filling-in, a name that reflects the introspective experience of seen the target getting filled-in by the background. The research project is divided into three related, though almost independent, sub-projects. The first sub-project is centered on learning the technique of functional Magnetic Resonance Imaging (fMRI) and applying it to the study of TF. The objective of this sub-project will be to identify the areas of the brain where the fading and filling-in of the target takes place. The results from this sub-project will not only have implications regarding theories of TF, but also regarding theories of normal surface perception. The second sub-project is centered on learning the technique of Event-Related Potentials (ERPs) and using it to investigate TF and perceptual awareness. The objective of this sub-project will be to utilize the "visual" or "sensory" ERPs (the so-called P1/N1 complex), which are believed to reflect the cortical processing of visual stimuli, as a functional marker to determine whether visual events occurring at the faded location are processed by the visual cortex. The results from this project will have important implications regarding theories of perceptual awareness and TF, as well as, theories regarding how sensory information is processed by the visual system. The third sub-project is a continuation of the behavioral investigation of TF. In this sub-project, the factors determining the duration of fading events will be investigated. Factors such as eye movements and coverts shift of visual attention (i.e., moving the focus of attention without accompanying eye movements) will be studied. The results of this project will have important implications regarding theories of TF and selective attention. Furthermore, when interpreted in the context of the other two sub-projects, these results will also provide important new information regarding the different brain regions where visual selective attention can influence perceptual processing. The University of British Columbia is uniquely equipped to house a project with the scope of the present proposal. UBC has research-dedicated, state-of-the-art, fMRI and ERP facilities at the Brain Research Center. Furthermore, UBC hosts a select group of highly expert academics in the fields of Cognitive Neurosciences and Visual Perception, who will provide the PI the appropriate learning training environment.
