Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

However, most biologists are of the opinion that a neuron, after receiving
signals, estimates the weighted average of the input signals and limits the
resulting amplitude of the processed signal by a non-linear inhibiting function
[6]. The reason for the non-linearity as evident from current literature [26] is
due to the concentration gradient of the Potassium ions within a neuronal cell
with respect to the Sodium-ion concentration outside the cell membrane. This
ionic concentration gradient causes an electrical potential difference between
the inner and outer portion of the neuronal cell membrane, which ultimately
results in a flow of current from outside to inside the cell. A neuron, thus, can
receive signals from its neighboring neurons. The variation of weights of the
input signals of a neuron is due to the differences in potential gradient between
a neuron and its surrounding cells. After the received signals are processed in a
nerve cell, an invasion in diffusion current occurs due to the synaptic
inhibiting behavior of the neuron. Thus, the processed signal can propagate
down to other neighboring neurons.
A neuron has four main structural components [1]-[2]: the dendrites, the
cell body, the axon and the synapse. The dendrites act as receptors, thereby
receiving signals from several neighborhood neurons and passing these on to a
little thick fiber, called dendron. In other words, dendrites are the free
terminals of dendrons. The received signals collected at different dendrons are
processed within the cell body and the resulting signal is transferred through a
long fiber named axon. At the other end of the axon, there exists an inhibiting
unit called synapse. This unit controls the flow of neuronal current from the
originating neuron to receiving dendrites of neighborhood neurons. A
schematic diagram, depicting the above concept, is presented in fig.14.1.
Dendrites
Nucleus
Dendron
Axon
Cell body
Fig. 14.1: A biological neuron.
Synapse