EE 671 – Neural Networks Lecture 1. Nervous System Source: http://www2.estrellamountain.edu/faculty/farabee/biobk/biobooktoc.html. Contents. Neuron Nervous System Brain Spinal Cord Senses Mind Intelligence Consciousness. Nerve Cells.
Three basic functions are performed by nervous systems:
Two main components of the PNS:
Most sensory input carried in the PNS remains below the level of conscious awareness. Input that does reach the conscious level contributes to perception of our external environment.
The human eye can detect light in the 400-700 nanometer (nm) range, a small portion of the electromagnetic spectrum, the visible light spectrum. Light with wavelengths shorter than 400 nm is termed ultraviolet (UV) light. Light with wavelengths longer than 700 nm is termed infrared (IR) light.
Neurons typically operate at a maximum rate of about 100 Hz, while a conventional CPU carries out several hundred million machine level operations per second. Despite of being built with very slow hardware, the brain has quite remarkable capabilities: