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Sue-Hyun Lee, Dwight Kravitz, Chris Baker; Task-dependent representations in Visual and Frontal Cortex during Working Memory. Journal of Vision 2012;12(9):290. doi: 10.1167/12.9.290.
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© ARVO (1962-2015); The Authors (2016-present)
Working memory is the process by which absent items are actively processed and maintained in memory in order to guide future action. This function has been associated with activation of prefrontal cortex, but it remains unclear whether the information of working memory is always stored in the prefrontal cortex independent of behavioral goals. Here, we used functional magnetic resonance imaging (fMRI) at 7 Tesla to investigate the representation of information about visual objects (watches, clocks, teapots, kettles, scooters and motorbikes) in occipitotemporal visual areas and frontal cortex during two delayed-match-to-sample tasks emphasizing different aspects of the objects. In both tasks, two sample object images were presented sequentially followed by a cue, indicating the particular sample object to be remembered, a delay and then a test image. In the "Part" task, participants were asked to decide whether an object part presented after delay period belonged to the remembered object. In the "Category" task, participants were asked to determine whether the test image was in the same category as the sample object. We used a searchlight procedure to identify cortical regions allowing decoding of remembered objects based on the multi-voxel response pattern during the delay period. In the Part task, the response of occipitotemporal but not prefrontal regions could be used to decode the identity of individual remembered objects. In contrast, during the Category task, prefrontal, but not occipitotemporal regions, showed significantly distinct representations for each remembered object. Neither visual nor frontal areas showed any significant decoding for the unremembered object. These results show that the distribution of object information held in working memory is dependent on the nature of the task - object-selective areas are primarily involved in maintaining visual, but not semantic information whereas prefrontal areas are primarily involved in maintaining category information.
Meeting abstract presented at VSS 2012
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