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Bioinformatics of the Brain

brain activity into specific commands or messages to control external devices,

such as robotic arms and wheelchairs, or to communicate with the outside

world via several applications (see Section 7.4.1). On the other hand, the re-

cent motivation for developing BCI technology is detection of the diseases by

decoding brain activity, especially for early diagnosis (see Section 7.4.2) as

well as emotion and face recognition processes [5]. For all purposes of using

BCI, EEG is the most preferred modality to capture neural activations among

other neuroimaging techniques (e.g., fMRI) due to attractive characteristics

such as being non-invasive, portable, and affordable in cost as well as having

excellent temporal resolution.

Various investigations have been carried out with the EEG method over

the last decades and BCI systems that use this method are called EEG-based

BCI systems. Besides non-invasive EEG, different types of intracranial EEG

(iEEG) could be also used to obtain electrical activity of the brain for BCI sys-

tems as an invasive method (please see Section 7.2.3). Although they provide

high-quality and accurate signals with better spatial resolution and fewer ar-

tifacts, these recording techniques require a more expensive setup than EEG,

and risky surgery [6].

7.2.2

History of EEG-based BCI

EEG-based BCI studies started almost 60 years ago with a mere idea and

reached today’s complex implementations by gaining momentum with the fast

improvement of technology over the past years. According to most of the liter-

ature, the milestone and the most famous study of BCI, where the term BCI

was first proposed, was published by Jacques Vidal in 1973 [1] in California

(UCLA). However, one of the first documented examples of BCI technology

was conducted by Alvin Lucier, an American composer, in 1965 when the term

BCI had not yet been coined [7]. In his experiment, he attempted to generate

resultant sounds with “Music for Solo Performer” by using enormously am-

plified brain waves, in particular, alpha waves. After this pioneering study in

art, multiple artists have done similar performances over further years [8].

In fact, the history of BCI systems with EEG dates back to Hans Berger,

who is a German psychiatrist. Berger developed a system that recorded brain

activity including alpha and beta waves from a human brain in 1929 [9] after

the animal studies by Richard Caton (1842–1926), Adolf Beck (1863–1939),

Pavel Yurevich Kaufman (1877–1951) and Vladimir Vladimirovich Pravdich

Neminsky (1879–1952) [6, 10]. After the invention of brain activity by Berger,

slow brain waves below alpha, delta, and theta, have been first reported by

Walter [11]. After that, Jaspers and Andrews [12] demonstrated a cortical

origin of the beta rhythm and introduced the term “gamma rhythms” for the

first time.

Throughout the 1950s to the 1970s, several researchers had doubts about

the cortical origin of the alpha rhythm, due to challenges in deciphering the

fundamental neuronal mechanisms behind brain wave generation persisted.