Introduction to Human Electroencephalography: Recording, Experimental Techniques, and Analysis

Introduction to Human Electroencephalography: Recording, Experimental Techniques, and Analysis

Gagandeep Kaur (Indian Institute of Technology Kanpur, India)
Copyright: © 2019 |Pages: 14
DOI: 10.4018/978-1-5225-7879-6.ch013

Abstract

This chapter is a general introduction to electroencephalography and popular methods used to manipulate EEG in order to elicit markers of sensory, cognitive perception, and behavior. With development of interdisciplinary research, there is increased curiosity among engineers towards biomedical research. Those using signal processing techniques attempt to employ algorithms to the real-life signals and retrieve characteristics of signals such as speech, echo, EEG, among others. The chapter briefs the history of human EEG and goes back to the origins and fundamentals of electrical activity in brain, how this activity reaches the scalp, methods to capture this high temporal activity. It then takes the reader through design methodology that goes behind EEG experiments, general schema for analysis of EEG signal. It describes the concept of early evoked potentials, which are known responses for study of sensory perception and are used extensively in medical science. It moves on to another popular manipulation of EEG technique used to elicit event related potentials.
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Electrical Activity Of Human Brain

There are two types of cells in human brain, Glial cells also known as Glia and the nerve cells also known as Neurons. Glia cells are termed as support cells of neurons and there are up to 50 times more glia cells than neurons in the central nervous system of vertebrates. Oligodendrocytes and Schwann cells are two types of glia cells that produce insulating myelin sheath which insulates cell outgrowths known as axons that conducts electrical signals. Glia cells play the important role of maintenance by removing debris after cell death. Third types of Glia cells, Astrocytes form the blood-brain barrier. The blood brain barrier aids the mechanism which restricts the movement of ions protects the neuronal tissue from toxins (Daneman & Prat, 2015). Some of glia cells also promote the release of growth factors and help nourish the nerve cells.

Neurons, also known as nerve cells play the fundamental role in transmission of electrical signals in nervous system. Soma or cell body, axon and dendrites and pre-synaptic terminals constitute the structural units of a neuron. Each part of the neuron plays specific roles in the electrical activity which it takes part. The neuronal membrane is bimolecular lipoprotein structure creating a barrier for free movements of ions such as sodium, potassium, chloride among others into and out of cell body. The concentration of ions within the cell body and in the interstitial space is critical in maintaining the resting state potential of neuron. Within the cell, the concentration of sodium and chloride ions in low and of potassium ions is high. The interstitial space has just the opposite and in a balanced state the resting state potential of the cell is measured to be around 80mV. The cell membrane regulates the ion exchange through its complex lipoprotein layers, which helps to maintain this resting state potential.

Figure 1.

The cell body is the metabolic centre of the cell, has the nucleus which stores genetic information of cell. The apical dendrites or dendrites are short extensions connected to the soma that act as receptor of electrical signals from other neurons. While the axon extends away from the cell body carrying the electrical signals to be transmitted to neighbouring neurons through synaptic terminals.

978-1-5225-7879-6.ch013.f01
Figure source (Somov, P.G., 2012).

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