Title
Electrocorticogram encoding of upper extremity movement duration.
Abstract
Electrocorticogram (ECoG) is a promising long-term signal acquisition platform for brain-computer interface (BCI) systems such as upper extremity prostheses. Several studies have demonstrated decoding of arm and finger trajectories from ECoG high-gamma band (80-160 Hz) signals. In this study, we systematically vary the velocity of three elementary movement types (pincer grasp, elbow and shoulder flexion/extension) to test whether the high-gamma band encodes for the entirety of the movements, or merely the movement onset. To this end, linear regression models were created for the durations and amplitudes of high-gamma power bursts and velocity deflections. One subject with 8×8 high-density ECoG grid (4 mm center-to-center electrode spacing) participated in the experiment. The results of the regression models indicated that the power burst durations varied directly with the movement durations (e.g. R(2)=0.71 and slope=1.0 s/s for elbow). The persistence of power bursts for the duration of the movement suggests that the primary motor cortex (M1) is likely active for the entire duration of a movement, instead of providing a marker for the movement onset. On the other hand, the amplitudes were less co-varied. Furthermore, the electrodes of maximum R(2) conformed to somatotopic arrangement of the brain. Also, electrodes responsible for flexion and extension movements could be resolved on the high-density grid. In summary, these findings suggest that M1 may be directly responsible for activating the individual muscle motor units, and future BCI may be able to utilize them for better control of prostheses.
Year
DOI
Venue
2014
10.1109/EMBC.2014.6943822
EMBC
Keywords
Field
DocType
high-density ecog grid,biomechanics,ecog high-gamma band signals,velocity deflections,high-gamma band encoding,elbow flexion-extension,long-term signal acquisition platform,movement onset,finger trajectories,primary motor cortex,pincer grasp,brain-computer interface systems,biomedical electrodes,center-to-center electrode spacing,regression analysis,electroencephalography,upper extremity prostheses,high-gamma power burst durations,extension movements,medical signal processing,encoding,somatotopic arrangement,upper extremity movement duration,high-gamma power burst amplitudes,electrocorticogram encoding,arm trajectories,distance 4 mm,shoulder flexion-extension,linear regression models,frequency 80 hz to 160 hz,individual muscle motor units,flexion movements
Computer vision,Elbow,Signal acquisition,Computer science,Brain–computer interface,Somatotopic arrangement,Speech recognition,Artificial intelligence,Physical medicine and rehabilitation,Primary motor cortex,Encoding (memory)
Conference
Volume
ISSN
Citations 
2014
1557-170X
0
PageRank 
References 
Authors
0.34
1
9
Name
Order
Citations
PageRank
Po T Wang1102.40
Christine E King2265.62
Colin M McCrimmon300.34
Susan J Shaw400.34
David E. Millett542.61
Charles Y Liu600.34
Luis A Chui700.34
Zoran Nenadic8213.92
An H. Do93211.35