Defining a Link between Perceptual Learning and Attention

PLoS Biology, Aug 2008

Takeo Watanabe and Yuko Yotsumoto explore the implications of a new study that shows that for perceptual learning of visual features involving multiple stimuli to occur, the brain needs to temporally "tag" the features, a learning process that requires paying attention.

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Defining a Link between Perceptual Learning and Attention

doi:10.1371/journal.pbio.0060221.g001 Defining a Link between Perceptual Learning and Attention Yuko Yotsumoto 0 Takeo Watanabe 0 0 Yuko Yotsumoto and Takeo Watanabe are in the Department of Psychology, Boston University , Boston , Massachusetts, United States of America. Yuko Yotsumoto is also at the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown , Massachusetts, United States of America; and the Department of Radiology, Harvard Medical School , Boston, Massachusetts , United States of America EExperienced jewelers routinely classify diamonds that xperts show amazingly high perceptual skills. appear very similar to the uninitiated into different grades with high precision. Within a few seconds, airport baggage security officers can detect forbidden inconspicuous materials through x-ray images. Such feats are possible because the experts' eyes are trained through practice and experience. Long after most aspects of brain development have ceased, repeated exposures or trainings improve our perceptual/sensory abilities, and cause neural reorganizations in the brain. Such experience-induced improvement, called perceptual learning [1], and the accompanying neural changes, called neural plasticity [2-6], underlie not only our ability to master a trade but operate at a more fundamental level to help us make sense of the world. We are constantly exposed to an overwhelming amount of sensory signals, most of which are not noteworthy. To function normally in the world, we must react quickly and precisely to the important signals, while ignoring or discounting the less important, just as organisms must do in the natural environment to survive. By directing attention only to important signals or being repeatedly exposed to signals in an important context, our sensory systems learn to process important signals more efficiently than the less-important signals. Reflecting this fundamental role of perceptual learning, studies have been conducted to examine mechanisms of perceptual learning and neural plasticity with various kinds of tasks and stimuli by using behavioral measurements [2,3] and neurophysiological [7,8] and brain imaging techniques [9,10]. Perceptual learning and neural plasticity have also been studied in all the sensory modalities including vision, hearing [11], and touch perception [12]. - Models of Perceptual Learning To explore the mechanism of perceptual learning, here we focus on visual perceptual learning. Visual processing consists of many different stages leading from eyes to cortical areas for cognitive processes such as decision making (Figure 1). It is unlikely that all types of visual perceptual learning involve the same cortical stage(s). The stage(s) in which one type of visual perceptual learning occurs may depend on many factors, including the learned visual feature such as orientation and contrast, the type of tasks such as a detection task or a discrimination task, and exposure to a feature without a task. For instance, some types of visual perceptual learning may only involve lower stages of visual processing, such as V1, while other types of visual perceptual learning may involve multiple stages of visual processing. Models Primers provide a concise introduction into an important aspect of biology highlighted by a current PLoS Biology research article. of different mechanisms are proposed depending on the stage(s) visual perceptual learning involves. (A) Early stage, local network model: Adini et al. [13] and Tsodyks, et al. [14] have proposed the model based on perceptual learning of contrast discrimination (indicating Copyright: 2008 Yotsumoto and Watanabe. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. whether two contrast values are the same or different). In their model, repeated presentation of a stimulus (a line presented in the center) together with its surrounding stimulus (lines presented around the central line) leads to a change in the visual cortex as a result of interactions between signals from the central and surrounding stimuli. That is, for an observer to learn a stimulus in one location (the central stimulus), the context in which the stimulus is presented (surrounding stimuli) plays an important role. The interactions can occur within the same cortex and therefore we do not have to assume interactions between cortical areas at different levels in the visual processing hierarchy. In this model, the neural reorganization due to perceptual learning can occur in a low-level cortex, including the primary visual cortex (V1), which is the first visual cortex onto which visual signals are projected. This model indicates the mechanism of a type of perceptual learning that can involve only one level of visual pr (...truncated)


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Yuko Yotsumoto, Takeo Watanabe. Defining a Link between Perceptual Learning and Attention, PLoS Biology, 2008, Volume 6, Issue 8, DOI: 10.1371/journal.pbio.0060221