Biomedical Engineering Reference
In-Depth Information
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CHAPTER 3
Electronic Detection Techniques
3.1 A Review of Neuron Field Potentials
Comprised of approximately 10 000million neurons, the brain is the most
important and complicated organ of the body. The basic architecture of each
neuron consists of two parts: the soma, the cell body, and the finger like
projections that radiate outward from the cell body in all directions, commonly
referred to as dendrites. (See Chapter 2 for a further look at neuron structural
details.) Simply put, the axon is the output extension of the cell body and the
dendrite is the input extension of the cell body. Neurons connect to each other
via an invisible bridge referred to as a synaptic connection. Several synaptic
connections can be made, for example, between two different dendrites, a soma
and dendrite, or between small spines that branch off surfaces of dendrites. It is
estimated that there are at least 1000 synaptic connections per cell. With such
remarkable intricate complexity, cells are able to communicate via these elec-
trical and chemical signaling connections.
The question that neuroscientists have long sought to address is how these
simple neurological connections allow the brain to function. Though the brain's
ability to function is not fully understood, it can be surmised that under-
standing it requires better appreciation of the formation of the patterns that
facilitate cognitive and intelligent response. Understanding the mechanism by
which these patterns are generated requires an examination of the inherent
forces that drive the system to form emergent complex and transient patterns,
allowing higher organic systems such as the brain to process multivariable
information. The inner workings of this intricate pattern formation within the
brain are investigated through smaller model networks that consist of the
essential elemental composition of the larger system. Though these artificial
neuronal networks do not afford a means to understand the deeper
complexities of the brain, they do offer a platform to study the mechanism of
function on a smaller scale.
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