ABSTRACT
The human brain is a dull gray and glistening white tissue having the texture of stiff pudding. Under high magnification the brain looks like an intricate three-dimensional maze, as shown in Fig. 7.1(a). Each component is being studied in painstaking detail, but despite our increasing knowledge of the brain’s structure our ignorance of how the brain works remains almost complete. However, neuroscientists have an advantage that workers in Artificial Intelligence do not yet have: a working model and an existence proof that problems in perception and cognition have at least one solution. If we knew how to look and what to look for, we might be able to see in Fig. 7.1(a), for example, a part of an algorithm for some problem in visual perception. (a) Highly magnified view of a cross section through the visual cortex of a rat using an electron microscope. The vesicle-filled profiles are presynaptic terminals. Several synapses, characterized by a presynaptic accumulation of vesicles and a postsynaptic thickening, are visible (courtesy of Simon LeVay). (b) A 16K Random Access Memory manufactured by MOSTEK. The magnification is about ten times less than in (a). Because silicon chips are essentially two-dimensional, the number of wires that can interconnect logical units in a large-scale device is severely limited. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315807997/2a26319a-018c-4d03-8167-91abc2cceb63/content/fig7_1_B.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
