Brain-computer interface: Difference between revisions

A Brain-computer interface (BCI) is a technological system of communication that is based on neural activity generated by the brain <ref name=”1”> Vallabhaneni, A., Wang, T. and He, B. (2005). Brain-Computer Interface. Neural Engineering, Springer US, pp. 85-121</ref>. It’s comprised of four main parts: a means for acquiring neural signals from the brain, a method for isolating the desired specific features in that signal, an algorithm to decode the signals obtained and a method for transforming the decoding into an action (Figure 1) <ref name=”2”> Sajda, P., Müller, KR. and Shenoy, K. V. (2008). Brain-Computer Interfaces. IEEE Signal Processing Magazine, 25(1): 16-17</ref> <ref name=”3”> He, B., Gao, S., Yuan, H. and Wolpaw, J. R. (2013). Brain-Computer Interfaces. Neural Engineering, Springer US, pp 87-151</ref>. This method of communication is independent of the normal output pathways of peripheral nerves and muscles. The signal can be acquired by using invasive or non-invasive techniques <ref name=”1”></ref>. This technology can help to provide a means of communication for people disabled by neurological diseases or injuries, providing a new channel of output for the brain to the user. It can also enhance functions in healthy individuals <ref name=”1”></ref> <ref name=”2”></ref> <ref name=”3”></ref>. BCIs are also named brain-machine interfaces (BMIs) <ref name=”4”> McFarland, D. J. and Wolpaw, J. R. (2011). Brain-Computer Interfaces for Communication and Control. Commun ACM, 54(5): 60–66</ref>.

The central nervous system (CNS) responds to stimuli in the environment or in the body by producing an appropriate output that can be in the form of a neuromuscular or hormonal response. A BCI provides a new output for the CNS that is different from the typical neuromuscular and hormonal ones. It changes the electrophysiological signals from reflections of the CNS activity (such as an electroencephalography – or EEG - rhythm or a neuronal firing rate) into the intended products of that activity, such as messages and commands that act on the world and accomplish the person’s intent <ref name=”5”> Wolpaw, J. R., Birbaumer, N., McFarland, D. J., Pfurtscheller, G. and Vaughan, T. M. (2002). Brain-Computer Interfaces for Communication and Control. Clinical Neurophysiology 113: 767–791</ref>. Since it measures CNS activity, converting it into an artificial output, it can replace, restore, or enhance the natural CNS output, changing the interactions between the CNS and its internal or external environment <ref name=”3”></ref>. The electrical signals produced by the brain activity can be detected on the scalp, on the cortical surface, or within the brain. As mentioned previously, the BCI has the function of translating these electrical signals into outputs that allow the user to communicate without the peripheral nerves and muscles. This becomes relevant because, since the BCI does not depend on neuromuscular control, it can provide another way of communication for people with disorders such as amyotrophic lateral sclerosis (ALS), brainstem stroke, cerebral palsy and spinal cord injury <ref name=”4”></ref>. It needs to be mentioned that a BCI also depends on feedback and on adaptation of brain activity based on that feedback. According to McFarland and Wolpaw (2011), “communication and control applications are interactive processes that require the user to observe the results of their efforts in order to maintain good performance and to correct mistakes <ref name=”4”></ref>.” The BCI system needs to provide feedback and interact with the adaptations the brains makes in response. The general BCI operation therefore depends on the interaction of the user’s brain (where the signals are produced that are measured by the BCI), and the BCI itself (that translates the signals into specific commands) <ref name=”5”></ref>. One of the most difficult challenges in BCI research is the management of the complex interactions between the concurrent adaptations of the CNS and the BCI <ref name=”3”></ref>.

Even though the main objective of BCI research and development is the creation of assistive communication and control technology for disabled people with different ailments, BCIs also have potential as a new type of interface for interacting with a computer or machine for people with normal neurological function. This could be applied to the general population in gaming, for example, or in high-stress situations like air traffic control. There could also be systems that enhance or supplement human performance such as image analysis, and systems that expand the media access or artistic expression. There has been some research into another possible application for the BCI technology: assistance in the rehabilitation of people disabled by a stroke and other acute events <ref name=”2”></ref> <ref name=”3”></ref>.