This workshop will address the characteristics, advantages, and disadvantages for BCI use of different brain signals and recording methods. This issue is extremely important at present: many research groups are debating the relative capacities and limitations of non-invasive (i.e., EEG from scalp electrodes), minimally invasive (i.e., ECoG activity from epidural or subdural electrode arrays), and maximally invasive (i.e., single neuron activity or local field potentials from multi-electrode intracortical implants) techniques. The primary topics will include: the possible communication and control capacities of EEG, ECoG, and intracortical signals; the problems that must be overcome to achieve stable recording over months and years (particularly with intracortical implants) and current efforts to address these problems; prospects for simplifying the required software and hardware; the clinical risks associated with invasive implants and the ethical issues involved in their development and implementation; and the future possibilities for using other signal acquisition methods such as MEG or fMRI activity. The participants will include clinical and basic neuroscientists, cell biologists, engineers, and clinicians.