Thursday, August 9, 2007

Keeping it Simple: Animal’s New Brain Design

Animal’s current brain design is much more complex than it has to be. Several of the cell assemblies in the human brain are needed mainly because the brain must process a huge number of low-level and unreliable sensory signals. By contrast, Animal’s chess environment is perfectly ordered and there are no sensory uncertainties. In addition, Animal uses very high-level sensors, which, if you think about it, already perform most of the recognition work that a real brain would have to perform in order to, say, recognize a pawn or a bishop.

In view of the above, I have decided to drastically simplify the design of Animal’s brain. I am taking out the association and sequence detection layers. They are not needed, in my opinion. Sequence detection is required only for variable time-scale sequences, which do not exist in Animal’s sensory environment. As a result, Animal’s brain design will be reduced to the following:
  • Sensor Layer
  • Sensory Cortex (signal separation)
  • Memory Layer (working memory)
  • Motor and Motivation Layer
  • Effector Layer

The memory layer is strictly working memory with a seven-item capacity (seven eyes). The function of an eye is to maintain an action cell alive for a short time.

An action cell consists of two neurons, a predecessor and a successor. The motor layer creates and manages all the action cells and organizes them into behaviors or action sequences. It receives input signals directly from the separation layer (sensory cortex) and channels them immediately to the effector layer. This is the most complex cell assembly in Animal’s brain. It handles motor conflict resolution, motivation (reinforcement learning) and anticipation. I’ll let you know how it all works out.

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