Cortical representations of visually specific information in working memory

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Visual working memory is a core cognitive function that allows people to actively maintain and manipulate information about stimuli that are no longer in view. With funding from the National Science Foundation, Dr. Frank Tong of Vanderbilt University is investigating how the human visual system actively maintains information about visual features and objects over delay periods of many seconds. This project is evaluating the hypothesis that visually specific content is maintained in working memory as a result of top-down feedback to early visual areas of the brain as well as to higher-level object-selective areas of the brain. The question is to what extent early visual brain areas can retain visually precise information about an actively remembered object. Dr. Tong is developing advanced methods to decode patterns of human brain activity for the purposes of reading out information about what item a person is maintaining in working memory. Experiments are investigating how multiple visual areas represent information about simple visual patterns and complex objects. Additional experiments are for testing whether these working memory representations are robust to visual interference, and whether their contents can be dynamically manipulated and modified based on the goals of the participant. The results are designed to provide new insights into the neural bases of visual working memory, its robustness to interference, and its capacity for flexible manipulation of remembered visual content. The visual working memory system provides an essential link between immediate perception and higher-level cognitive processes, and is important for mental imagery, vision-based learning, visuospatial planning, and the maintenance of an updated representation of the objects in one's environment. Understanding the neural bases of visual working memory is important for advancing knowledge of human brain function and is also relevant to developing better methods to improve learning in educational settings. Research on visual working memory is also a prerequisite to developing better methods to diagnose individuals with impairments in visual working memory, and it may eventually lead to treatment interventions. The methodological advances from this project are also highly relevant to research on brain-computer interface, and they constitute an advance in the ability to decode specific mental content from patterns of human brain activity.