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On a moment-by-moment basis we are faced with an environment that is in a continual state of flux, changing over time and space. Coherent and adaptive behavior in this complex environment is supported by the interplay of a variety of sensory, perceptual and cognitive systems. Attention, for instance, provides a powerful coping mechanism that mediates the selective processing of information that is consistent with our current behavioral goals and intentions. The purpose of the research conducted in the Laboratory fo Attention, Brain, and Behavior is to clarify the perceptual, cognitive, and neural mechanisms of selective attention. More specifically, we use vision as a model information processing pathway to investigate three fundamental questions about attention: 1) What are the functional consequences selective attention? A long line of studies has demonstrated that one of the consequences of selectively attending to information is that there is a processing advantage for attended information that can be measured in terms of improved behavioral performance and enhanced neural activity. However, selectively attending to information also has clear and measurable costs. For example, when two masked targets are presented in a rapid sequence in the same spatial location on a computer screen and observers are asked to identify both targets, identification of the first target (T1) hinders the identification of the second target (T2) for about 500 ms. This transient impairment in report is thought to reflect a processing limitation that renders T2 unattended and is commonly known as the attentional blink (AB). There are two key aspects to the AB phenomenon that make it a useful tool for studying the functional consequences of selective attention. First, because all information is presented in a single spatial location in the typical AB task, the consequences of selective attention can be studied independently of shifts of spatial attention. Second, and most importantly, the AB provides a brief temporal window within which one can study the extent to which unattended information is processed. Determining the extent to which unattended information is processed is a cornerstone issue in the attention literature and much of the research conducted in the LABB is dedicated to the systematic investigation of this issue. Some relevant papers are: Giesbrecht, B., Sy, J. L., & Lewis, M. K. (in press). Personal names do not always survive the attentional blink: Behavioral evidence for a flexible locus of selection. Vision Research.pdf
Giesbrecht, B., Sy, J. L., & Elliott, J. C. (2007). Electrophysiological evidence for both perceptual and post-perceptual selection during the attentional blink. Journal of Cognitive Neuroscience, 19, 2005-2018.pdf
Giesbrecht, B., & Kingstone, A. (2004). Right hemisphere involvement in the attentional blink: Evidence from a split-brain patient. Brain & Cognition, 55, 303-306.pdf Giesbrecht, B., Bischof, W. F., & Kingstone, A. (2004). Seeing the light: Adapting luminance reveals low-level visual processes in the attentional blink. Brain & Cognition, 55, 307-309. pdf Giesbrecht, B., Bischof, W. F., & Kingstone, A. (2003). Visual masking during the attentional blink: Tests of the object substitution hypothesis. Journal of Experimental Psychology: Human Perception & Performance, 29, 238-258.pdf Giesbrecht, B., Dixon P., & Kingstone, A. (2001). Cued shifts of attention and memory encoding in partial report: A dual-task approach. Quarterly Journal of Experimental Psychology - Section A, 54, 695-725. Giesbrecht, B. & Dixon P. (1999). Isolating the interference caused by cue duration in partial report: A quantitative approach. Memory & Cognition, 27, 220-233. McFadden, S. M., Giesbrecht, B. L., & Gula, C. (1998). Use of an automatic tracker as a function of its reliability. Ergonomics, 41, 512-536. Giesbrecht, B. & Di Lollo, V. (1998). Beyond the attentional blink: Visual masking by object substitution. Journal of Experimental Psychology: Human Perception and Performance, 24, 1454-1456.pdf 2) What are the mechanisms that control the selective effects of attention? A central tenet of all neurobiological models of attention is that there is a system of brain areas that control our ability to voluntarily orient selective attention to different aspects of our environment. My work on attentional control is focused on determining the extent to which the brain systems involved in the control of selective attention change depending on the type of information that is attended. More specifically, I have used fMRI alone and, more recently in combination with EEG, to assess the relationship between the neural mechanisms that mediate the control of orienting seleslagterEtAl2006.pdf Kelley, T. A., Serences, J.T., Giesbrecht, B., & Yantis, S. (2008). Cortical mechanisms for shifting and holding visuospatial attention. Cerebral Cortex, 18, 114-125 (Epub: April 13, 2007 doi:10.1093/cercor/bhm036).pdf Slagter, H. A., Giesbrecht, B., Kok, A., Weissman, D. H., Kenemans, J. L., Woldorff, M. G., & Mangun, G. R. (2007). fMRI evidence for both generalized and specialized components of attentional control. Brain Research, 1177, 90-102.pdf Giesbrecht, B., Weissman, D. H., Woldorff, M. G., & Mangun (2006). Pre-target activity in visual cortex predicts behavioral performance on spatial and feature attention tasks. Brain Research, 1080, 63-72.pdf Slagter, H. A., Weissman, D. H., Giesbrecht, B., Kenemans, J. L., Mangun, G. R., Kok, A., & Woldorff, M. G. (2006). Brain regions activated by endogenous preparatory set-shifting as revealed by fMRI. Cognitive, Affective, and Behavioral Neuroscience, 6, 175-189.pdf van Zoest, W., Giesbrecht, B., Enns, J. T., & Kingstone, A. (2006). New reflections on visual search: Inter-item symmetry matters! Psychological Science, 17, 535-542.pdf Giesbrecht, B., Kingstone, A., Handy, T. C., Hopfinger, J. B., & Mangun, G. R. (2006). Functional neuroimaging of attention. In A. Kingstone & R. Cabeza (Eds.), Handbook on Functional Neuroimaging of Cognition. Cambridge, MA: MIT Press. Giesbrecht, B. & Mangun, G. R. (2005). Identifying the neural systems of top-down attentional control: A meta-analytical approach. In L. Itti, G. Rees, & J. Tsotsos (Eds.), Neurobiology of Attention. New York: Academic Press/Elsevier. Weissman, D. H., Giesbrecht, B., Song. A. W., Mangun, G. R., & Woldorff, M. G. (2003). Conflict monitoring in the human anterior cingulate cortex during selective attention to global and local object features. NeuroImage, 19, 1361-1368.pdf Giesbrecht, B., Woldorff, M. G., Song, A. W., & Mangun, G. R. (2003). Neural mechanisms of top-down control during spatial and feature attention. NeuroImage, 19, 496-512.pdf Giesbrecht, B., & Mangun, G. R. (2002). The neural mechanisms of top-down control. In H.-O. Karnath, D. Milner, & G. Vallar (Eds.), The Cognitive and Neural Bases of Spatial Neglect. Oxford, UK: Oxford University Press. 3) How is selective attention shaped by experience? The question how selective attention is shaped by experience is the newest addition to my research program. We have started several investigations in this area that are investigating the role of experience by testing the contextual influences on attention, the influence of social information, and the impact of training on attention. Tipper, C. M., Handy, T. C., Giesbrecht, B., & Kingstone, A. (2008). Brain responses to biological relevance. Journal of Cognitive Neuroscience. (Epub ahead of print: doi: 10.1162/jocn.2008.20510).pdf Giesbrecht, B., Camblin, C. C., Swaab, T. Y. (2004). Separable effects of semantic priming and imageability on word processing in human cortex. Cerebral Cortex, 14, 521-529.pdf
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