Abstract
Scientists at the European Molecular Biology Laboratory have investigated
how embryonic stem cells become mature nerve cells. They assessed the complex
interplay of molecules during the differentiation process. Consequently, new insights
into the role of a protein called SOX2 in neurons emerged. This protein is expressed by
a gene, SOX2, located on chromosome 3 in humans. This gene is a sex-determining Yrelated HMG box2 and serves as a marker for neural stem and progenitor cells [1].
Progenitor stem cells become neurons and glial cells. The ratio of glia to neurons in the
human brain is 10:1. This suggests that glial cells play significant roles in cognitive
functions. Glial cells of CNS are divided into microglia and macroglia. The microglia
are macrophage-like cells, which function as a phagocyte. Macroglia consist of
astrocytes and oligodendrocytes. Oligodendrocytes act as CNS equivalent to
myelinating Schwann cells in the peripheral nervous system (PNS).
Neuroimaging is a branch of medical imaging that focuses on the brain. Among all
imaging techniques, magnetic resonance imaging (MRIs) and MEGs
(Magnetoencephalographs) are favorites of medical doctors. MRI has two variants:
functional MRI and structural MRI. In this chapter, both of them are discussed.
Detection and monitoring of the progression of neurodegenerative diseases are
performed with MEG by analyzing neural complexity and the Grassberger-Procaccia
correlation dimension. Lempel-Ziv complexity is a better option. Positron emission
tomography (PET) is a useful procedure to measure the metabolic activity of the cells
of body tissues. PET helps monitor biochemical changes in the body.
Electroencephalography is used to characterize states of consciousness of the brain.
EEG is not discussed in the present chapter since the aim of the chapter is not to
present all neuroimaging techniques but to cover a select few depending on the author’s
own background and experience.