EEG Decoding Reveals the Temporal Dynamics and Functional Relevance of Goal-Relevant Representations

Abstract

Abstract:Models of action control assume that abstract task-set settings regulate lower-level stimulus/response representations. Yet, we know little about the functional and dynamic properties of task-set representations in humans. Using a cued task-switching paradigm, we show that information about task sets and lower-level stimulus/response aspects can be extracted through decoding analyses from the scalp electrophysiological signal (EEG) on the single-trial level and with high temporal resolution. Task-sets are active throughout the entire processing cascade and trial-to-trial variations in task-set strength emerges as a remarkably strong predictor of variability in performance, both within and between individuals. Also, taskset strength is related to stimulus representation strength at an early period and to the strength of response representations at a later period, consistent with the notion that task-sets coordinate successive, lower-level representations in a concurrent manner. These results demonstrate a powerful approach towards uncovering stages of information processing and their relative importance for performance. Keywords: Executive control, Task switching, EEG. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/219741 doi: bioRxiv preprint first posted online Nov. 15, 2017; 3 EEG Decoding Reveals the Temporal Dynamics and Functional Relevance of Goal-Relevant Representations in HumansThe efficiency of information processing differs both moment to moment, and from one individual to the next. Such variability could reflect the quality of low-level, stimulus or response representations. Alternatively, it may arise from the strength of abstract, task-set representations that instantiate or control lower-level processes (1-3). For example, in the experimental paradigm we used in the current work (see Figure 1a), participants were informed on each trial through auditory cues, which of two tasks to perform (4, 5). For the color task, they attended to the color singleton within the array of objects and responded via button press whether the exact color was orange or purple. Similarly, for the orientation task, participants attended the orientation singleton and responded whether the line tilted to the left or to the right.In this situation, successful performance requires lower-level representations of the task cue, of the target location, and of the task-relevant feature/response. However, it may also require abstract task-set representations that differentiate between the color task context and the orientation task context and that ensure an adequate configuration of lower-level