Month: September 2010

There is now a pretty strong consensus that the cerebral cortex (which is, by no means, the entire brain, but it is likely that this is where culture is carried) is organized into small columns of neurons. In a 1978 essay Vernon Mountcastle called these minicolumns and suggested that they have about 100-300 neurons each. He estimated that the neocortex consists of 600,000,000 of these minicolumns. He also suggested that these minicolumns are organized into macrocolumns, about 600,000 of them — implying that there are hundreds of minicolumns per macrocolumn. (Mountcastle was clear that these numbers were just order of magnitude estimates & that is all I need for my purposes.) That makes these macrocolumns roughly the size of a typical invertebrate nervous system of 10K to 100K neurons. So, here’s my metaphor: Your neocortex consists of 600,000 buzzing bees going about their business.

The point of the metaphor is that, just as individual bees are autonomous agents (which must, nonetheless, feed and reproduce in a group), so the macrocolumns are autonomous agents (which are physically coupled to many other such agents). Bees go about their business by sensing optical and chemical gradients and features and by moving their bodies and excreting chemicals. The macrocolumns are not directly connected to the external world, but they have extensive inputs and outputs to other macrocolumns and to other regions of the brain and nervous system. From a purely information processing point of view, they are as capable of action as are bees. They “sense” neurochemical gradients in the intersynaptic space and act on their sensations by excreting chemicals into that space.