I thought the brain was just the body of mass in your head until a few days ago. Apparently your gut has 500 million neurons, almost half as much as your spinal cord.

The cerebrum and cerebellum are the actual brain in our skull, and the brainstem connects it to the spinal cord that goes all the way down your body, making up the central nervous system (CNS). But the peripheral nervous system—made up of the spinal and autonomic plexuses and nerves—fill the rest of our body, making up the true brain. Information is gathered across your entire body and through sensory receptors—eyes, nose, ears, etc.—and sent to the CNS. The CNS responds by commanding muscles, organs, sensory receptors, glands, blood vessels, etc.

This input/output process is done through the somatic and autonomic nervous system. Sensory neurons carry afferent signals (inputs) and motor neurons carry efferent signals (outputs)

Those signals control everything from sexual arousal and regular breathing (autonomic nervous system—involuntary physiologic processes) to the act of jumping over a fence running from the police with quadricep, hamstring, calf, glute, core, and arm muscle contractions (somatic nervous system—voluntary actions). What would happen if we take control of these processes electronically to boost human potential?

A BCI can be connected to some of those neural areas in the CNS to gather information and react. For example, a somatotopic map can be made to see what region of the cerebrum controls what part of the body, and someone with paraplegia can "think" to move their legs even though the legs won't actually move. That data that can be recorded in the motor cortex (cerebrum) and trigger an action sequence to move a prosthetic leg. This is already possible even though it already seems like sci-fi.

Gathering (electrical) input and output is key. Instead of just relying on the body for input data, data can be sourced externally. Around 10% (>100K people) of blindness cases in the US are attributed to glaucoma, a chronic eye disease that damages the optic nerve — the connection between the retina (where light data is received) and brain. What if light could be gathered externally and sent directly to the brain, bypassing the biological visual input? Or, if the retina still works, like in most glaucoma cases, why cant you capture electrical signals that the retina generates and pass them over to the brain?

Into the future, I see these specialized implants as the key to solving diseases that impact all of humanity, from the input side (sensory devices) to the output side (prosthetics) or biological tissue.

Even simple-looking things like a bicep curl involve complex processes like:

1. Signal formed in motor cortex
2. Signal travels through motor neurons to spinal cord
3. Motor neurons send electrical impulses to the neuromuscular junction
4. At the junction, neurotransmitters (primarily acetylcholine) are released, triggering electrical changes in muscle fibers and leading to contraction
   1. Biceps brachii contract
   2. Opposing triceps brachii relaxed
   3. Signals to stabilize shoulder and wrist muscles

Natural neurologic pathways need to be used for precise movement with low error (minimizing expected movement - actual movement), which probably develop due to brain plasticity. When you do a bicep curl for the first time, you have to intentionally move in a certain way for correct form, but over time, it eventually becomes unintentional. Once we figure out how to engage complex somatic processes, like how to trigger motor neurons without disrupting other pathways to do precise things, the output side of a BCI does not need to be restricted to artificial tissue, but can actually move biological tissue. That would be game-changing. Instead of popping a nicotine patch before executing a highly-levered trade, a derivative trader could trigger dopamine release with an app on their phone for the extra emotional support. (Would we have phones then?)

Humans becoming cyborgs is a scary thought—mostly because of the way it has been covered in movies and media—but most people don't realize we already are cyborgs. When people leave their phone at home on accident, they feel like they literally lost a limb. They sense something is off and feel like something is missing. It's a part of their bodies. Most people I know at college can't even write a full essay without ChatGPT. When they try to make a creative thought, going to ChatGPT is an immediate instinct. Trust me I know—I've been to more than one hackathon.

At Armada, we spent hours thinking about how to organize a hackathon event where participants had no tertiary help (Internet, devices, LLMs, etc.) and we couldn't think of anything that truly worked. These things are just too embedded into our lives, especially in the creative process. A fashion designer looks at images on Pinterest to make lookbooks for their latest FW25 collection while coders look at X's (?) on X to find the next best web framework to build their new wrapper.

Along with the brain and the body (biological peripheral tissue), there is a new (there for .0000075% of human evolution) layer, artificial peripheral tissue. We treat this stuff the same way we treat our body parts, relying on it for daily tasks. We feel like shit when it stops working (spraining your ankle ~= wifi is dead // shin splints means I can't run for a week ~= ChatGPT is down so I can't write for a week). And over time, I expect this layer to become increasingly important, possibly even eclipsing the biological peripheral tissue at some point.

This raises a ton of cool questions, but the one I find most interesting is something that was revealed to me with deep introspection on Eddy Street. People have been thinking about the sense of Self—is it just one person in you or is there a devil on your left shoulder and an angel on your right? Freud and Plato's models of consciousness speak the most to me.

Freud thinks the mind is made up of three actors, id, ego, and the superego. Id represents your hedonistic desires (Instinctual Desires), ego is internalized societal and moral principles (Moral Compass), and ego tries to keep both in check with rationality (Reality Negotiator). Plato views it as: epithumos with physical and metaphysical desire (Appetite/Desire), thumos with spiritedness (Spirit/Emotion), and logos (Reason) that subjugates the (appetite) epithumos with the help of thumos (emotion).

Without knowing this stuff, I recreated the tripartite structure, but slightly different on a cold car ride to Boston a few weeks ago:

It was clear that my base Self aligns with the superego with a hint of thumos, with strong domination by the id/epithumos. The ego/logos is superior but dominates very inconsistently. If our mind is made up of three actors, what happens when we introduce the fourth — an AI via a BCI? I represent this as purple.

In the left-most image, the logos dominates over the AI but the AI stays superior over the other two agents. At least one part of our brain keep the AI in check. But the AI could also dominate (middle) or become the mind's sense of Self (right-most). That presents insane implications for biological-digital cyborgs (us) as the artificial peripheral tissue layer gets more and more significant. I definitely need to think about this more.