The scope of this system is pretty amazing, if you think about it.

Let’s consider the brain (only the brain – no spinal column or other neuronal networks) of an average adult male. It contains an estimated 100-500 trillion synapses (let’s use a conservative 150 trillion for this discussion). That’s 150 trillion possible connections between axons and dendrites in the brain itself. Just to give you a sense of the scale, if you had a dollar for each of your synapses, you could personally pay off the U.S. Federal debt 7 times over.

Now, as we mentioned earlier, each synapse includes a synaptic cleft, which is estimated 20-40 nanometers (nm) in width. 1 nm = one 1-billionth of a meter. A sheet of paper is ~100,000 nm thick, and a human hair is approximately 80,000 – 100,000 nm wide.

Let’s average the synapse width to 30 nm.

150 trillion synapses at 30 nm each = 4500 trillion nanometers.

Which, in terms of everyday distance converts to

4500 kilometers, or nearly 2800 miles

That’s the driving distance between Toronto and Vancouver, all dithered across trillions of synapses in one human brain alone.

But that can’t possibly be… can it? How could that much space fit inside the human brain? Well, if you consider that the span of a synapse is ~30 nm, you have plenty of room, especially if you double it back on itself.

3800 pixels will fit into a 200-pixel-high space, when folded back on themselves