<p>The major cell of the central nervous system is the <b><u>neuron</u></b>. Neurons are pretty much the most basic unit of the brain, as well as the most complicated cell in the human body.</p><p>The brain has about 100 billion neurons with an estimated 200 trillion connections between them (Buszaki, 2006). A neuron has a cell body (also called soma, or perikaryon); dendrites, which are the branched&nbsp; projections of a neuron that act to conduct the electrical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. Dendrites extend a short distance from the soma (each of them having spines that absorb neurotransmitter); and an axon (also called fiber), which connects one neuron with others. The fibrous axons occupy more space in the brain than neurons, dendrites, and spines combined.&nbsp;</p><p>Neuronal membranes are specialized for electro-chemical events, the firing of action potentials and the release/reception of neurostransmitters. This is how neurons communicate to one another. The dendrites and cell bodies of the neurons receive information, and the axons transmit the ﬁring pattern of the cell to the next neuron. Generally, each neuron receives synaptic input from hundreds or perhaps thousands of other neurons, and its axon distributes this information via collaterals (branches) to hundreds of other neurons. The overwhelming majority of neurons are used for the processing of information and are called interneurons. The more dramatic the level of processing, the more the interneurons are involved.</p><p>Neurons prefer to take the shortest paths with their surrounding peers. They receive most of their information from their immediate neighbors and act locally (p. 45). In order to communicate with distant neurons, it requires the use of costly connections metabolic resources and connections to transporting electrical pulses over long distances (Buzsaki, 2006).</p><p><br></p><p style="text-align: center;"><img src="@@PLUGINFILE@@/synapses.png" alt="" width="216" height="165" role="presentation" class="img-responsive atto_image_button_text-bottom"><br></p><p style="text-align: center;"><br></p><p style="text-align: left;">Communication between neurons occurs almost exclusively at specialized junctions called&nbsp; <b>synapses</b>, using biological molecules called <b>neurotransmitters</b>. Neurotransmitters modify ion movements across the neuronal membranes of the synapse and alter neurotransmission (with each action potential neurotransmitters travel across the synaptic gap) — neurotransmitters can be excitatory or inhibitory in their action, or modulate synaptic excitability. The post-synaptic neuron will modify its ﬁring pattern depending on the summative effect of all the synapses acting upon it at any moment in time. The action of neurotransmitters depends also on the speciﬁc receptor type; there is an ever-increasing number of receptor subtypes allowing for even more complexity of information processing within the CNS. Drugs are being designed to act on those receptors for therapeutic purposes.<br></p><p style="text-align: center;"><img src="@@PLUGINFILE@@/axon.png" alt="" width="670" height="374" role="presentation" class="img-responsive atto_image_button_text-bottom"><br></p><p>When measuring EEG—we are measuring “action potentials” along the axon. An action potential is a firing—bam!—that is the swapping of potassium and sodium along the border of the axon. Much of the substance of the brain consists of <b>axons</b>, also called ﬁbers, which connect one part of the brain with other areas. Low frequency oscillations (i.e., delta and theta) coordinate long-range communications, between lobes of the brain (von Stein, Chiang, &amp; Konig, 2000).&nbsp;</p><p>This stage of wiring the brain happens in utero, with the long connections being the most fundamental (Grubin, 2011). It is these long fibrous white matter tracks that theta and delta traverse. Many of the axons are myelinated by oligodendrocites (a type of glial cell), this “insulation,”&nbsp; serve to increase the speed of axonal conduction; the thicker the <b>myelin sheath</b>, the faster the conduction. Axons originating from one area (cortex or nucleus) and destined for another area usually group together and form a tract, also called a pathway (or fasciculus).</p><p style="text-align: center;"><img src="@@PLUGINFILE@@/mitochondrion.png" alt="" width="679" height="419" role="presentation" class="img-responsive atto_image_button_text-bottom"><br></p><p style="text-align: left;">Moreover, there are even more numerous glial cells and finely branch blood vessels that support and nourish the neurons. The neuronal circuits in each subdivision constitute local networks, which are further integrated to form global neural systems across subdivisions or divisions. Current neuroscience is based on the belief that these networks and systems operate through specific mechanisms and play specific functional roles in the living body.<br></p><p style="text-align: left;"><br></p>