Neural Cascade

The human cerebral cortex has approximately of 16 billion neurons (The Cellular Composition of the Human Brain). Only about 0.1% of this 16 billion are connected to either sensory or to motor cells (Spitzer, p 87?). The overwhelming bulk of cortical neurons communicate only with other cortical neurons. From the biological structure of the human cortex, we know that sensory data travels a well-defined path from receipt to integration and then to the frontal lobe. In the frontal lobe, the path is not clear, but eventually a behavioral decision is made and an impulse is sent to perform an action, the output. Since only 0.1% of the cortical cells are at the input or the output, let’s assume that the width of the path the neural signal travels are about 0.05% wide. This back-of-the-envelope calculation leads to a path of 198 jumps from input to output.

In this context, let me mention the cognitive scientists 100-Step Rule. This rule of thumb is based on the observations that neurons react in about 5 milliseconds and that it takes about 0.5 second for a person to cognitively react to a sensory perception. Thus approximately 100 steps of neural processing occur in that arc.

Angels walking up a spiral staircase, diminishing with distance

Details get less certain with more distance

Each of these 100 steps—let’s say 50 from sensory input to prefrontal lobe processing, then another 50 steps from decision to motor or speech response—must surmount Almost Gates. That is, 50 Almost Gates lie between sensation and internal worldview. And each Almost Gate transmits its input to output with a guaranteed fidelity dependent on the magnitude of the Almost Gate.

A little mathematics is necessary here. Developing 95% match gives the same output. Two Almost Gates in a row has a match of 90.25%.

Fidelity loss shown in spreadsheet columns of each step in the neural cascade

Declining fidelity in each step of neural cascade

This cascading of neurons, of Almost Gates of 95% fidelity, through 50 steps, shows that if you and I receive the same input, there is only a 8% chance that input is received in all its features, emotions, and implications with the same fidelity by both of us.

With the Almost Gate, neural cascades, and the magnitude of the brain’s interconnections, you can well appreciate how concept elevation can result in quite different mental worlds for separate people.

If you’re like me, you might be wondering—how can this be when I think so logically? Is thinking more than logical or emotional reasoning?