3rd International Conference on Gait and Mental Function

Washington, DC



February, 2010

Klaus Gramann1, JT Gwin2, D Ferris2, S Makeig 1, Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA
2 Gait Lab, University of Michigan, Ann Arbor MI

Cognition on the Run

Though much human cognition occurs during dynamic motor actions, most studies of human brain dynamics examine subjects in seated or prone conditions. To test the feasibility of using high density electroencephalography (EEG) to study brain processes during human locomotion, we used 248-channel EEG, optical motion capture, and a force-measuring treadmill to record brain/body dynamics of 12 healthy young adult subjects performing a visual oddball discrimination task while standing, walking (0.8 m/s and 1.25 m/s), and running (1.9 m/s).

We applied infomax independent component analysis (ICA) to parse EEG signals into maximally independent components whose activities were then time-locked to the onset of the visual stimulus. Independent components were clustered across subjects by similarities in their equivalent dipole locations and event-related potential (ERP) profiles using EEGLAB routines (Delorme and Makeig, J Neurosci Meth, 2004). During running mechanical artifacts dominated the EEG signals, but these could be substantially reduced through subtraction of an ERP-like noise profile synched to gait cycle events.

By these means we could reliably identify a late positive (‘P300’) peak in the ERP following infrequent target stimuli in all gait conditions. As in prior work using seated subjects (Makeig et al., PLOS Biology, 2004), we identified multiple classes of independent brain processes contributing to the target-stimulus ERP including frontal processes contributing to the pre-response positivity and parietal processes contributing to the post-response positivity. These findings demonstrate that high density EEG can be used to study brain dynamics during whole-body human movement. Supported by Office of Naval Research N000140811215.

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