The influence of pathway complexity and reference frame proclivity on single-trial brain dynamics
Plank, M.1, Onton, J.2, Makeig, S.2, and Gramann, K.2
1Allgemeine und Experimentelle Psychologie, Ludwig-Maximilians-Universität München; 2Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego
Two experiments analyzed single-trial brain dynamics accompanying path integration based on distinct reference frames. Participants, preferentially using an allocentric ("Nonturners") or an egocentric reference frame ("Turners"), traversed virtual tunnels of varying path complexity. Tunnels contained either one turn, two turns into the same, or into opposite directions. At the end of a passage participants indicated their momentary position relative to the starting point ("point-to-origin").
High-density EEG was recorded continuously and decomposed by Independent Component Analysis (ICA). A second order, Context-ICA (xICA) decomposition was applied to separate out single-trial variability associated with different complexity levels and reference frame usage.
The results revealed specific changes in event-related spectral dynamics that varied with parameters of path layout and/or the reference frame used during path integration. The analyses revealed the brain dynamics of Turners and Nonturners to reflect configural (not history-free) updating of representational primitives along outbound trajectories.