This thesis analyzed the cortical representation of arm kinematics, target encoding, and goal encoding using subdural electrocorticographic (ECoG) recordings in humans. Using a joystick-based visuomotor task, subjects performed both a standard, delayed match-to-sample center-out task as well as a circular tracing task. Spectral analyses of the ECoG signals clearly showed significant cosine tuning for hand velocity, direction, position and speed throughout the cortex. In particular, velocity tuning was best represented spectrally in a high gamma band from around 90-150 Hz in the primary motor cortical regions. In dorsolateral prefrontal cortex (DLPFC), cortical activity in the 150-250 Hz band of the ECoG signal showed robust, non-directional encoding for the goal during both the delay period prior to moving as well as the final hold period. This study suggests that ECoG is an effectively modality for applications where both movement kinematics and goal selection need to be decoded. Given ECoG's higher spatial and spectral frequency content as well as its higher signal to noise ratio versus scalp-based electroencephalography (EEG), ECoG is an optimal signal choice in brain-computer interface (BCI) applications.
|Advisor:||Moran, Daniel W., Leuthardt, Eric C.|
|Commitee:||Barbour, Dennis L., Leuthardt, Eric C., Moran, Daniel W., Petersen, Steven E., Smart, William D., Thoroughman, Kurt A.|
|School:||Washington University in St. Louis|
|School Location:||United States -- Missouri|
|Source:||DAI-B 70/11, Dissertation Abstracts International|
|Subjects:||Neurobiology, Biomedical engineering, Electrical engineering|
|Keywords:||Arm movements, Brain-computer interfaces, Electrocorticography, Electroencephalography, Goal orientation, Neural correlates|
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