Recurrence
One of the surprising revelations that I discovered while preforming emulations of animal connectomes is the huge amount of recurrence. The brain literally folds back on itself over and over again. To illustrate this idea, let's look at C elegans again. Keep in mind that we are working with 302 neurons. Neurons connect to a set of other neurons. This connected set has a number of axons that link back to the originating neuron. If we look at the Interneuron AVAL, AVAL connects to 77 other neurons. These 77 neurons connect to another set of neurons, so on and so on. Each neuron can have multiple connections to other neurons. For example, AVAL has 11 synaptic connections to the neuron DA6. From the first set of neurons that AVAL connects too, there are 83 total synaptic and gap junction connections from those 77 neurons back to AVAL. If we take those 77 neurons and follow what neurons they connect too, we find from that second set (Layer 2), there are 573 neuronal connections back to...