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What Is a BCI?
"BCI" is an acronym for brain-computer interface. There are several other names that are often used as well, such as brain-machine interface, thought-translation device, or (more generally) neuroprosthetic, which all generally describe the same type of system. As these names suggest, a BCI is an interface, or connection, between a person's brain and a computer. This interface is designed so that it does not rely on a person's normal output pathways, such as the arm and hands, for interacting with the external environment. A BCI removes the intermediate steps of the spinal cord, peripheral nervous system, and musculature, which is particularly important in individuals who may not have full use of their motor abilities. Therefore, the goal of most BCI systems is to provide a platform for a person with motor disabilities to interact and communicate more effectively with their environment and other people.
A BCI generally consists of three parts: a signal acquisition module, a signal classification/translation module, and an application module. The signal acquisition module is made up of the brain signal, the amplifier and digital signal processor, and a computer. The brain signal can be collected in many different ways, including electroencephalogram (EEG), electrocorticogram (ECoG), micro-electrodes, or magnetoencephalogram (MEG), to name a few. EEG and ECoG are the most commonly used in human research, and are what are used in the NITRO lab.
Once the signals are recorded into the computer, a variety of computations are done on the brain signals to determine what the subject is attempting to do. For example, when a person makes a movement (or THINKS about making a movement), there is a change in the brain signal, which is recorded on one or more electrodes. The computer learns what these changes are, and how to translate these into a device command. The final step in a BCI is the application. The application uses the control signals from the brain to drive an external system, such as a computer cursor or wheelchair. This output in turn allows the user to fine-tune their behavior, which we call "closing the loop." When the loop is closed, the user can see the effects that changes in their brain-waves has on the output, allowing them to adjust and adapt their behavior much more quickly.
The goals of our BCI research are:
- Characterize output of a BCI and compare results with real movement.
- Develop a standard system of measuring BCI performance using existing measures of human movement, such as Fitts' Law.
- Drive development of an implantable recording system for use in humans that is save and reliable for many years of use.
