Abstract

The DARPA report^[1] notes that the human cerebral cortex is comprised of 100 billion neurons, each having about 1,000 dendrites that form about 100 trillion synapses. If you multiply that by its operating frequency of about 100 Hz, you get 10,000 trillion interconnections per second. These last two numbers (10¹⁴ connections and 10¹⁶ connections per second) form the basis for the graph in the DARPA report labeled Computational Requirements. The cortex not only has this prodigious capacity but dissipates about 10 watts, weighs 3 pounds, covers 0.15 square meters and is about 2 millimeters thick. To say it is something substantial for designers of neural systems to shoot for is a considerable understatement.

© 1991 Optical Society of America