- 1 week ago
Okay, time for some education! And expounding upon superheroes! Huzzah! (No spoilers contained for anything. Also huzzah!)
Really long lecture under the cut! Let me know if there’s anything anybody wants clarifying here, I’ll edit for clarity or post additional notes as necessary.
So, one of the common things that you see in many supers is heightened reflexes. This is especially true of speedsters such as the Flash or Quicksilver, but can be seen in many others, including Captain America and others who’ve taken the super serum, which is what got me thinking about this in the first place. Wiki stoically keeps to the line that he’s at “peak human strength/speed/reflexes/etc.”, but that’s inspired bullshit.
With speedsters, they’re so far outside of the realm of the possible that I can’t really even begin to speak to them. But with MCU!Cap and Red Skull, I can get into details. Because the in universe explanation for their capabilities is basically comprehensive gene therapy: a complete overhaul of their genetics, and likely massive epigenetic change as well. Genetics indicates the sum total of what DNA is capable of encoding for, but epigenetics determines the actual amount that any one gene will be translated into a functional form. This is entirely a tangent, but worth noting. This is part of how, for example, identical twins can end up not looking the same without injury ever coming into play: genetically, they are as close to identical as can be, but their genetics have been utilized differently and epigenetically affected by different experiences, along with more transient responses to conditions in their environment.
No word on whether this is integral to Schmidt’s face falling off, but I’d call it a fair bet.
Now, I’m afraid, it’s time to be pelted with more science facts, with nary a mention of superheroes until the end. I promise, it will be worth it.
So. Back to reflexes. I’m talking both in-grained, unconscious reflexes and learned motion (muscle memory). We have certain built-in reflexes that don’t actually require the brain’s involvement at all: put your hand on a hot stove by accident, and your hand moves away before the pain ever reaches your brain. What you’ve experienced is a somatic reflex arc, which only initially sends stimulus as far as the spinal cord before sending back a very simple signal: in this case, move away. During this period the signal is also sent to the brain, but the sensation of pain is not consciously felt until after the reflex has already started. I’ll get back to why in a moment.
Muscle memory is what you are talking about when you refer to any more complex, learned action. This even includes walking, holding objects, dodging things your siblings throw at your head, the ability to type, etc. etc. This is referred to commonly as reflex, but these actions are managed by the motor cortex, and therefore are slower to access. However, compared to an untrained individual, a person with many hours of repetitive training will respond more quickly and accurately to complete a given task. This is why you train for sports, learn to drive, go to boot camp: just as a fact you’ve heard many times can be retrieved without relative effort, physical tasks work just the same.
Still, there is an upper limit to how fast you can undertake a complex reaction. This is in part due to physical capability: We’re large animals and therefore take time to move. Probably the fastest unconscious reflex you’ll find is blinking: about 0.1 second per blink, so fast that your brain usually tricks you into believing the world didn’t go dark for a fraction of a second. But that’s not the only reason.
See, the reason why our built-in reactions bypass the brain is because there is also a limit to the base signalling speed of our neurons. The signal that our body uses is called the action potential: A sudden, relatively large electrical current that is sent through nerve fibers, which can be caused by any number of different kinds of stimulus. It’s fast. In fact, it’s the fastest biological signal that we have for carrying messages over long distances. Yes, long distances: other electrical phenomena in neurons barely ever propagate more than a few millimeters, but an action potential can make it all the way through your body. the fastest of which work at 80–120 meters per second. Fast, yes?
Slow. Electrical impulses in electronics travel at close to the speed of light. Why is there such a difference between the two systems? Both are made to conduct electricity, so why are our bodies so bad at it?
The reason is that honestly, we aren’t made for sending signals. As electrical conductors, our cells are terrible, and most of them aren’t insulated. Insulation is what allows electrical signals to travel great distances, rather than just leaking out into their surroundings and fizzling out unceremoniously. A lot of our nerves have found a partial solution to that, though, which I’ll detail in a moment.
Also, rather than using the zippy little electrons that electronics do to transmit charge, our nerves are stuck using whole ions: in this case, charged sodium and potassium atoms to create and then shut off the signal.
I’ll probably talk about the action potential at length at some point, but I’ll give a quick run-down now: sodium ions enter the cell through specific channels in the cell membrane, creating the dramatic positive electrical potential, which is then cut off by both a different part of the sodium channel closing on a timer, and potassium leaving the cell. These two things together cause the electrical potential of the cell to drop down to near its resting state.
Now, to bring in that insulation thing again: The fact that the cell needs to have open membrane to do all this action potential stuff is a problem: it limits the speed of the action potential to how fast these channels can run. But leaving only one patch open to start the signal and then insulating the rest wouldn’t work: the signal would peter out quite quickly, because, again, the cell is a horrible conductor. So what’s been done instead is a compromise: The main transmission line of the nerve cell (the axon) is usually coated in little strips of insulation, made out of special cells that roll themselves up around the axon like especially clingy friends. Between them, small gaps allow the action potential to get a boost from ion channels in the neuron’s membrane. This acts much the way a wireless signal booster does for your wifi, allowing the action potential to go further on. This is part of why our transmission speed is so slow: The voltage generated at each little open node can be felt near-instantaneously by the next node down the line, but the time it takes for it to respond is significant. Hence, we’re stuck at 80-120 m/s for the signal speed.
It then takes a short time before the sodium channels can start opening up again to make a new action potential, a waiting time known as the refractory period. Yes, really. I’m very impressed that none of the undergrads in my class giggled at that. I’m especially impressed none of the grad students did either.
So, this limits the frequency of action potentials. At its fastest, neurons will fire at about 500 times per second (500 Hz), which is limited by the absolute refractory period, which cannot be altered. However, most signals are further limited by the relative refractory period, which causes action potentials to happen less and less frequently as they continue to fire. This generally limits the fastest frequency of action potentials to 200 Hz, maximum. This the binary signal of our internal electrical systems, so this determines how fast information can be encoded and processed. Still, 200 times a second is a lot, right?
Wrong again, when compared to modern computers. I have a seven year old processor in my PC right now that manages 2.4 billion signals per second (2.4 GHz). This leads to a slight tangent that should be addressed: Why aren’t computers out-competing us at everything yet, if they are literally a billion times faster than us? Well, the one thing we really excel at is parallel processing. Rather than just sending pieces of information through a single pipeline, our brain uses vast arrays of interconnected neurons working in tandem to process information. This is what makes it possible for us to do tasks that are actually phenomenally complex, like looking at a specific animal you’ve never seen before and correctly identifying it as a cat. Yes, really. Even Google, the master of computerized pattern recognition, has only just managed to get their systems to begin accurately recognizing cats on sight.
Now, I’m going to get back to superheroes. Huzzah!
So, when your average HYDRA mook tries to shoot Cap and he brings up his shield, he’s seeing the shot coming, something in his brain remembers an action paired to the sight, which then triggers the motor cortex to send out a signal to his muscles, getting his shield up in time to deflect the shot. How fast can he do that? I’ve got no clue, the movies are no real help, and the wiki just states that no one except for Schmidt managed to land a hit on him. But I can give an example of speedy reaction times that are nearly as American as him: Baseball.
A pro-level batter has about 0.4 seconds to go from determining what pitch has been thrown at them to making the bat connect with the ball, taking it through that same set of sight, recognition, calling response, and execution. We can probably consider this to be among the fastest responses among humans that you’ll get to a situation involving a moving object.
Now, I’ve shown you by this point why that kind of reaction speed is impressive. That’s essentially at the maximum speed a human’s nervous system can handle. For this particular task, the player is at peak human condition. Steve’s still faster, because no one could match him well enough to hit him. Same for the Red Skull.
I both do not want and very much want to see them play baseball now.
What I’ve been trying to get at is that somewhere along the line is that to react faster than humanly possible is not presently biologically possible. Every step of the way, there’s something throttling the speed at a very fundamental level. Which is what makes this idea fascinating to me. Some very fundamental mechanism in the human nervous system has been completely altered to allow faster signalling speed in these guys. I went down the list of limitations, because each one is a potential area that might have changed: the speed at which action potentials are generated, the frequency at which they fire, how fast they move, and how far they have to go within the nervous system to figure out what to even do with themselves.
So honestly, if I got a chance to examine one of them, I’d love to do a full study on their nervous system. Are the ion channel proteins different? That’s determined genetically, so that means genome sequencing would be a must. What’s the conductance of their nerves? That can be figured out with some relatively simple electrical equipment so long as it’s (expensively) precise, but to get into the precise how of it, you need to get into the lipid biochemistry of the cell membrane. Again, genetics might play a role, but if it’s altered levels of synthesis for base components that’s different, that’s epigenetic modification that needs to be examined, which would require a whole separate lecture to explain.
Or possibly the axoplasm inside the axon has altered conductance! Better test that too. Also the insulating Schwann cells need to similarly be examined. Maybe they’re better at their job! Hell, maybe the action potential itself is stronger, and thus requires fewer stopovers to replenish itself!
- Even in the smallest little details, Steve and Schmidt are biologically boggling.
- The more you learn about science, the more awesome superheroes become
- If I was in the MCU, I’d absolutely be a certified mad scientist.
- 1 week ago
- 1 week ago
i’m waiting for someone to write epic meta on why the reason bucky is so popular with female fans is bc his storyline being about being stripped of agency and personal autonomy resonates particularly with female experiences
I think you… just did it?
(via snowinacan)Source: theladymonsters
- 1 week ago
- 1 week ago
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- 1 week ago
#i didn’t realize until exactly this moment#that these are actually tiny shorts over tights#and not just very tights-ish pants with a weird seam detail#i feel like the world is brand new#my eyes are open#colors are more vivid#there is a god#captain America#booty booty booty (via bewaretheides315)
(via canned-spoop)Source: buckysdildo
- 3 weeks ago
Come on,Rogers,move it!
guys, remember how i can make everything about neuroscience? this scene, though. if steve’s hippocampus — that’s memory storage — is as super as the rest of him the way that the times square exhibit says…it’s actually not that far-fetched to conclude that when steve remembers something, he remembers it like this. like, this might not be an exaggeration. steve might be able to literally watch memories play out in front of him.
his nightmares must be horrible.
(via hey-mayonegg)Source: tirynsed