PT - JOURNAL ARTICLE AU - K. J. Miller AU - S. Zanos AU - E. E. Fetz AU - M. den Nijs AU - J. G. Ojemann TI - Decoupling the Cortical Power Spectrum Reveals Real-Time Representation of Individual Finger Movements in Humans AID - 10.1523/JNEUROSCI.5506-08.2009 DP - 2009 Mar 11 TA - The Journal of Neuroscience PG - 3132--3137 VI - 29 IP - 10 4099 - http://www.jneurosci.org/content/29/10/3132.short 4100 - http://www.jneurosci.org/content/29/10/3132.full SO - J. Neurosci.2009 Mar 11; 29 AB - During active movement the electric potentials measured from the surface of the motor cortex exhibit consistent modulation, revealing two distinguishable processes in the power spectrum. At frequencies <40 Hz, narrow-band power decreases occur with movement over widely distributed cortical areas, while at higher frequencies there are spatially more focal power increases. These high-frequency changes have commonly been assumed to reflect synchronous rhythms, analogous to lower-frequency phenomena, but it has recently been proposed that they reflect a broad-band spectral change across the entire spectrum, which could be obscured by synchronous rhythms at low frequencies. In 10 human subjects performing a finger movement task, we demonstrate that a principal component type of decomposition can naively separate low-frequency narrow-band rhythms from an asynchronous, broad-spectral, change at all frequencies between 5 and 200 Hz. This broad-spectral change exhibited spatially discrete representation for individual fingers and reproduced the temporal movement trajectories of different individual fingers.