Decoding abstract and concrete concept representations based on single-trial fMRI data

Previously, multi‐voxel pattern analysis has been used to decode words referring to concrete object categories. In this study we investigated if single‐trial‐based brain activity was sufficient to distinguish (e.g., mercy) versus concrete (e.g., barn) concept representations. Multiple neuroimaging studies have identified differences in the processing of versus concrete concepts based on the averaged activity across time by using univariate methods. In this study we used multi‐voxel pattern analysis to decode functional magnetic resonance imaging (fMRI) data when participants perform a semantic similarity judgment task on triplets of either or concrete words with similar meanings. Classifiers were trained to identify individual trials as concrete or . Cross‐validated accuracies for classifying trials as or concrete were significantly above chance (P < 0.05) for all participants. Discriminating information was distributed in multiple brain regions. Moreover, accuracy of identifying single trial data for any one participant as or concrete was also reliably above chance (P < 0.05) when the classifier was trained solely on data from other participants. These results suggest and concrete concepts differ in representations in terms of neural activity patterns during a short period of time across the whole brain. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.