Our sensory pathways are provided with only rudimentary information from the receptor neurons that sense our environment. For example a photoreceptor can only signal the light intensity at a particular point in space. From this basic information, the neural circuitry of the eye is able to compute many complex features of our visual world, such as the orientation of edges, the direction of moving objects and their colour, as well as allowing this circuit to work over light intensities spanning 9 orders of magnitude. These and many other computations all occur within the retina, before any information is sent to higher areas of the brain.
The above example illustrates two important points:
1. To understand what higher areas in the brain are doing we need to know what information is being sent there, i.e. what computations have occurred in the earlier circuits?
2. Neural circuits have solved a range of computations that are relevant for artificial intelligence, such as
image analysis
and
pattern recognition
. How are these computations implemented by the neural circuitry?