Brain regions that retain the spatial layout of tactile stimuli during working memory – A ‘tactospatial sketchpad’ ?

Description: Participants performed a delayed match-to-sample retro-cue paradigm. Each trial started with the consecutive presentation of two vibrotactile sample stimuli to the tip of the left index finger. A mask stimulus (vibration of the full display at maximum intensity) was presented together with a visual retro-cue. The retro-cue (‘1’ or ‘2’) indicated which of the two sample stimuli had to be retained for the 12 second WM delay. After the delay phase, participants were presented with two further stimuli, one of these stimuli was identical to the memorized stimulus (target) and the other stimulus was a slightly changed version of it (foil). Subsequently, participants indicated with a right-hand button-press (index- or middle-finger), which of the two stimuli was the target. Stimulus combination and response-mapping were randomized and balanced within each experimental run. Image acquisition was time locked to the WM delay phase and decoding analyses were performed independently within the six 2 sec time bins t1 to t6. Additionally, data from the time bin before and after the delay phase were also analyzed. Whole-brain searchlight analyses with support vector machine (SVM) classification were performed for each stimulus pair, resulting in six decoding accuracy maps per time bin. Averaged, normalized, and smoothed images were used in the 2nd level analysis. A t-contrast testing for above chance decoding accuracies across the WM delay phase (time bins t2 - t6) was computed

Related article: http://doi.org/10.1016/j.neuroimage.2018.05.076