The
brain functions by a complex network of specialized cells named neuron.
Neuron cells have three main parts, the cell body (soma), dendrites, and
an axon. Signals travel into the dendrites, through the soma, and
out of the cell via its axon into the dendrites of another neuron. Communication
between neurons is both chemical and electrical. At resting state
the sodium inside the soma and the potassium found outside of the soma
are in balance. As the potassium builds up outside of the soma the
cell becomes exited. Once a threshold level of excitement has been
reach the sodium and potassium briefly switch places causing the soma to
go from a positively charged resting state to a negatively charged excited
state. It is at this moment that the electrical charge is sent out
of the cell through its axon to the dendrites of its connecting cells.
The space between one cell’s axon and another dendrites is known as the
synapse. [Chudler/Graci]
It is estimated that the brain contains 10 million neurons. Of these
10 million neurons, the number of synapses for a “typical” neuron is between
1,000 to 10,000. How the brain is able to manage such astronomical
numbers is a phenomenon still little understood. One model that may
hold answers for us is a neural network. [Chudler]
image from washington.edu