TY - JOUR T1 - Proceedings of the Second International Workshop on Advances in Electrocorticography. JF - Epilepsy Behav Y1 - 2011 A1 - A L Ritaccio A1 - Boatman-Reich, Dana A1 - Peter Brunner A1 - Cervenka, Mackenzie C A1 - Cole, Andrew J A1 - Nathan E. Crone A1 - Duckrow, Robert A1 - Korzeniewska, Anna A1 - Litt, Brian A1 - Miller, John W A1 - Moran, D A1 - Parvizi, Josef A1 - Viventi, Jonathan A1 - Williams, Justin C A1 - Gerwin Schalk KW - Brain KW - Brain Mapping KW - Brain Waves KW - Diagnosis, Computer-Assisted KW - Electroencephalography KW - Epilepsy KW - Humans KW - United States KW - User-Computer Interface AB -

The Second International Workshop on Advances in Electrocorticography (ECoG) was convened in San Diego, CA, USA, on November 11-12, 2010. Between this meeting and the inaugural 2009 event, a much clearer picture has been emerging of cortical ECoG physiology and its relationship to local field potentials and single-cell recordings. Innovations in material engineering are advancing the goal of a stable long-term recording interface. Continued evolution of ECoG-driven brain-computer interface technology is determining innovation in neuroprosthetics. Improvements in instrumentation and statistical methodologies continue to elucidate ECoG correlates of normal human function as well as the ictal state. This proceedings document summarizes the current status of this rapidly evolving field.

VL - 22 UR - http://www.ncbi.nlm.nih.gov/pubmed/22036287 IS - 4 ER - TY - JOUR T1 - A procedure for measuring latencies in brain-computer interfaces. JF - IEEE Trans Biomed Eng Y1 - 2010 A1 - Adam J Wilson A1 - Mellinger, Jürgen A1 - Gerwin Schalk A1 - Williams, Justin C KW - Brain KW - Computer Systems KW - Electroencephalography KW - Evoked Potentials KW - Humans KW - Models, Neurological KW - Reproducibility of Results KW - Signal Processing, Computer-Assisted KW - Time Factors KW - User-Computer Interface AB -

Brain-computer interface (BCI) systems must process neural signals with consistent timing in order to support adequate system performance. Thus, it is important to have the capability to determine whether a particular BCI configuration (i.e., hardware and software) provides adequate timing performance for a particular experiment. This report presents a method of measuring and quantifying different aspects of system timing in several typical BCI experiments across a range of settings, and presents comprehensive measures of expected overall system latency for each experimental configuration.

VL - 57 UR - http://www.ncbi.nlm.nih.gov/pubmed/20403781 IS - 7 ER - TY - JOUR T1 - A practical procedure for real-time functional mapping of eloquent cortex using electrocorticographic signals in humans. JF - Epilepsy Behav Y1 - 2009 A1 - Peter Brunner A1 - A L Ritaccio A1 - Lynch, Timothy M A1 - Emrich, Joseph F A1 - Adam J Wilson A1 - Williams, Justin C A1 - Aarnoutse, Erik J A1 - Ramsey, Nick F A1 - Leuthardt, E C A1 - H Bischof A1 - Gerwin Schalk KW - Adult KW - Brain Mapping KW - Cerebral Cortex KW - Electric Stimulation KW - Electrodes, Implanted KW - Electroencephalography KW - Epilepsy KW - Female KW - Humans KW - Male KW - Middle Aged KW - Practice Guidelines as Topic KW - Signal Processing, Computer-Assisted KW - Young Adult AB -

Functional mapping of eloquent cortex is often necessary prior to invasive brain surgery, but current techniques that derive this mapping have important limitations. In this article, we demonstrate the first comprehensive evaluation of a rapid, robust, and practical mapping system that uses passive recordings of electrocorticographic signals. This mapping procedure is based on the BCI2000 and SIGFRIED technologies that we have been developing over the past several years. In our study, we evaluated 10 patients with epilepsy from four different institutions and compared the results of our procedure with the results derived using electrical cortical stimulation (ECS) mapping. The results show that our procedure derives a functional motor cortical map in only a few minutes. They also show a substantial concurrence with the results derived using ECS mapping. Specifically, compared with ECS maps, a next-neighbor evaluation showed no false negatives, and only 0.46 and 1.10% false positives for hand and tongue maps, respectively. In summary, we demonstrate the first comprehensive evaluation of a practical and robust mapping procedure that could become a new tool for planning of invasive brain surgeries.

VL - 15 UR - http://www.ncbi.nlm.nih.gov/pubmed/19366638 IS - 3 ER - TY - JOUR T1 - Using an EEG-based brain-computer interface for virtual cursor movement with BCI2000. JF - J Vis Exp Y1 - 2009 A1 - Adam J Wilson A1 - Gerwin Schalk A1 - Walton, Léo M A1 - Williams, Justin C KW - Brain KW - Calibration KW - Electrodes KW - Electroencephalography KW - Humans KW - User-Computer Interface AB -

A brain-computer interface (BCI) functions by translating a neural signal, such as the electroencephalogram (EEG), into a signal that can be used to control a computer or other device. The amplitude of the EEG signals in selected frequency bins are measured and translated into a device command, in this case the horizontal and vertical velocity of a computer cursor. First, the EEG electrodes are applied to the user s scalp using a cap to record brain activity. Next, a calibration procedure is used to find the EEG electrodes and features that the user will learn to voluntarily modulate to use the BCI. In humans, the power in the mu (8-12 Hz) and beta (18-28 Hz) frequency bands decrease in amplitude during a real or imagined movement. These changes can be detected in the EEG in real-time, and used to control a BCI ([1],[2]). Therefore, during a screening test, the user is asked to make several different imagined movements with their hands and feet to determine the unique EEG features that change with the imagined movements. The results from this calibration will show the best channels to use, which are configured so that amplitude changes in the mu and beta frequency bands move the cursor either horizontally or vertically. In this experiment, the general purpose BCI system BCI2000 is used to control signal acquisition, signal processing, and feedback to the user [3].

UR - http://www.ncbi.nlm.nih.gov/pubmed/19641479 IS - 29 ER - TY - JOUR T1 - ECoG factors underlying multimodal control of a brain-computer interface. JF - IEEE Trans Neural Syst Rehabil Eng Y1 - 2006 A1 - Adam J Wilson A1 - Felton, Elizabeth A A1 - Garell, P Charles A1 - Gerwin Schalk A1 - Williams, Justin C KW - Adult KW - Brain Mapping KW - Cerebral Cortex KW - Communication Aids for Disabled KW - Computer Peripherals KW - Evoked Potentials KW - Female KW - Humans KW - Imagination KW - Male KW - Man-Machine Systems KW - Neuromuscular Diseases KW - Systems Integration KW - User-Computer Interface KW - Volition AB -

Most current brain-computer interface (BCI) systems for humans use electroencephalographic activity recorded from the scalp, and may be limited in many ways. Electrocorticography (ECoG) is believed to be a minimally-invasive alternative to electroencephalogram (EEG) for BCI systems, yielding superior signal characteristics that could allow rapid user training and faster communication rates. In addition, our preliminary results suggest that brain regions other than the sensorimotor cortex, such as auditory cortex, may be trained to control a BCI system using similar methods as those used to train motor regions of the brain. This could prove to be vital for users who have neurological disease, head trauma, or other conditions precluding the use of sensorimotor cortex for BCI control.

VL - 14 UR - http://www.ncbi.nlm.nih.gov/pubmed/16792305 IS - 2 ER -