How can a gigantic creature combat neural lag?

Question

For the purposes of the question, it doesn't really matter if the creature's a continent-sized amoeba or a particularly large kaiju. Speed of thought is relatively painfully slow in organic creatures, since it uses electrochemical processes. It is so slow, in fact, that the speed can be expressed in meters per second. It's not too terrible for peripheral signals like from limbs, as it will just make the creature react more sluggishly.

But what about the brain? If a creature's brain is 100 meters in diameter or more (say, aforementioned sentient amoeba for instance), it will take a neural impulse around a second to propagate through it. I feel this is not enough for high brain functions to exist, and it can easily cause different part of the brain to lose synchronization, so the question is, what evolutionary adaptation macrolife can have to circumvent the neuron reaction speed limitations?

Answer 1

Solution: neurons that funnel flashes of light.

Have you heard of fiber-optic cables? No? In a nutshell, the cable doesn't serve to transfer electrical energy but instead funnels photons within a reflective cable. This technology is what allows the internet to function worldwide. This is clever, because nothing is faster than light when it comes to crossing long distances quickly. All you need is a source of light, means of funnelling it in the desired direction and a receptor at the other end.

How are Kaiju's supposed to make use of this in the first place?

Organisms have mastered the usage of light since prehistory approximately 3.5 billion years ago. Photoreceptors have practically evolved alongside intelligence, without them we wouldn't be as complex as we are today. Likewise, bioluminescence is an extremely old trait shared my many species i.e. fireflies, anglerfish and some species of jellyfish. Nocturnal animals like cats have reflective cells lining their retinas called Tapetum Lucidum.

Perfect. Life has a means of producing, reflecting and detecting light.

There's two ways this can work:

Intracranial optic cables serving as neurons, which essentially allow a gigantic brain to think at a reasonable speed. This doesn't mean the Kaiju will be smarter. No, the limiting factor is the size of the cables. To prevent the light from 'leaking' from the cables the reflective layer needs to be a certain thickness. Otherwise a single nerve firing off a light signal would cause a ripple effect which would give the Kaiju a seizure. This is the least optimal arrangement but it allows for comically large brains.

Peripheral nervous system using optic cables, which completely negates the lag Kaiju would normally have. Signals sent from the brain are now instantly relayed through the body to the extremities. This is far more efficient than having a secondary brain. No doubt, this is the optimal way to go.

Both solutions imply the nerves connecting different body parts will be thick hollow structures with reflective inner surfaces. One end would have a bioluminescent organ while the other photoreceptor cells. Either the organ flashes when it receives a nerve impulse or a valve open and closes the cable. Either way is good.

Answer 2

The most basic adaptation to faster neural functioning is the ability to precipitate metals. Once a life-form has the ability to precipitate metals and build metal structures within its body, it is not a particularly great evolutionary step to neurons with metal axons.

If we have a metal axon with a seperate metal core, like a biologically-created coaxial cable, we've stepped up the speed of neural transmission from hundreds of metres per second to near light-speed. The main delay will then be the time it takes for a neuron to depolarise and the wave of depolarisation to travel to the metal axon. From there, the voltage differential will propagate at light speed to the far end of the axon where the dendrites will depolarise at the slow speed, and transmit their signal to the next neuron via molecular diffusion of neurotransmitters across the neural gap.

It might seem that a metal axon would be rigid, and could not bend, but this axon would be many times thinner than a hair. When metals are that thin, they bend very easily. They would be no more fragile than common myelinated neurons.

As to what metal might be used... silver would provide the lowest electrical resistance, followed by gold and copper. However, the scarcity of silver and gold might mean that copper is used for no other reason than its relatively low resistance and relatively high availability.

So... with metal axons, an organism could be hundreds or thousands of metres long, yet still have the same speed of neural transmission as a much smaller creature.

Edit

Since there is some misunderstanding as to how this works, I'll explain further:

A regular neuron's cell wall has a charge across it. The cell wall is a poor conductor. Within the cell wall are voltage-sensitive ion gates. When neural junction activation causes sufficient depolarisation as a field effect around the junction, the voltage-sensitive gates open briefly, sending a wave of depolarisation across the cell membrane. Since the gates aren't particularly fast, and since the field effect of the charge is limited, this limits the transmission speed.

Now, if we were to precipitate metals inside and outside the cell membrane, the metal layers, being conductive, would transmit the voltage along their mass at lightspeed. In effect, there would be a continuous metal fibre inside the axon, and a continuous metal sheath would replace the periodic myelin sheath.

So, instead of a long axon with slow gates and perhaps myelin to make the axon a little faster, we'd have in effect a cellular-scale coaxial cable, where the insulating layer between the conductors would be the cell membrane. As I have said, this will transmit the voltage differential from one end of the axon to the other at lightspeed, from where the usual ion gate depolarisation effect continues.

Answer 3

You should consider that human brains have limited large-scale synchronization, and they're a lot smaller than 100m across. Clearly you can get human-equivalent intelligence in a human-sized brain that's a thousand times smaller. Fictional kaiju don't seem to demonstrate any kind of superhuman intelligence, suggesting that their thinky wetware isn't obviously more capable than our own and as such doesn't actually need to be a whole lot bigger. You could have a little blob for consciousness, and then just an awful lot of infrastructure to control all those muscle cells that would let an enormous animal actually move about.

Now, making a conscious decision to waggle an arm obviously has an awful lot of latency associated with it if your brain (or body) is tens or hundreds of metres across, which could be quite annoying, but there are ways around this. You might not need conscious control over every last muscle... perhaps much of the actual detail of co-ordinating the motor neurons that drive a limb is delegated to local semi-autonomous brain regions and other chunks of neural tissue distributed throughout the body and the limb in question. There's a reasonable chance that octopus brains are organised a little like this, with individual arms having a reasonable amount of independent action, with a central brain that co-ordinates but doesn't directly control ever little detail.

Maybe kaiju brains are more distributed through their bodies, and maybe they operate much more like a closely knit group of semi-independent (though not necessarily conscious) brains.

what evolutionary adaptation macrolife can have to circumvent the neuron reaction speed limitations?

The lazy answer would be to say that they evolved nerves that operated fast enough to enable them to move and act in a way that furthers your plot.

Our nerves already have some adaptations for improved conduction speed in the form of saltatory conduction, but there's nothing to say that what we have is necessarily as good as nerves could ever get. Alternative electrochemical signalling mechanisms could be much faster, or maybe just plain electrical signalling given suitable insulation forming. Other exotic things like internal waveguides that would allow sonic or ultrasonic signals to propagate at the speed of sound in a liquid (several times that of the speed of sound in air) or maybe hollow structures (maybe rigid, maybe filled with clear liquid or other material like a kind of fiber-optic) that use bioluminescent signalling, etc etc.

Answer 4

Does it need full brain synchronisation?

There's a few misconceptions here. A brain is not a computer. We don't need synchronisation in such detail. The method used is more flexible. Also consider that information can be processed in a brain structure and then send to the other side of the brain for further processing. Higher brain functions also don't require speed in most cases like movement does. You don't need to have an answer ready in a nanosecond.

Now consider higher brain functions. If higher brain functions would be affected negatively, why put them far apart in the first place? Humans have higher brain functions with our current brains. Why not just put important brain areas close to each other as humans have? There should be no reason for brain areas to talk to each other so far apart.

That raises another question. Why do you need a brain 100m in size? If you just supersize a whale, you don't need extra brain to steer the thing. You can do with the same brain as before. Extra brain offers assistance with control for examole, but isn't required. A fly can fly it's wings as it has many routine 'programs' inside it. It isn't a conscious effort to beat a wing. Same for heart rate, blood vessel constriction and much more. These processes are either handled indirectly or if directly they don't necessarily need complex brain structures to be controlled.

Summary

You can make due with less brain to steer increasingly large creatures. Higher brain functions are very much possible in large brains, you just need to put the right brain parts together. Synchronisation isn't the same as with computers, allowing for more flexibility in brain communication.

Answer 5

The Brain has a Smaller Brain.

A lot of the physical motions do not require the brain. They only route through the spine. Humans already do this. Most of the walking and running action does not require the brain. The brain can focus on speeding up, slowing down, avoiding obstacles and such. Keeping in pace and shifting weight on uneven ground only uses the spine.

The part of the giant monster's brain that manages intelligence is not much bigger than a human brain. Asynchronization is not a problem for this sub-brain.

When the animal wants to move forward the microbrain sends signals to the legs that say "move forward". The legs nearer the head get the signal first and start moving first. The legs near the end start moving last. The legs know how long to delay after getting the signal in order to keep them in step with each other. This calculation is done in the part of the spine where each leg joins.

Each individual leg then manages its own gripping and balancing issues without sending signals back to the spine.

If the creature needs to suddenly stop the brain sends the "STOP" command down the spine. There might be a delay of several minutes until all the legs get the message. But this delay is rarely noticeable to an observer, considering how physics demands each leg takes ten minutes to take a single step in the first place.

Answer 6

In its natural environment

The same way we do, by sheer size.

When you attempt to swat a bluebottle or similar fly, it can see, and react to your motion, faster than you can see that it has done so. However the bluebottle is no threat to us, much in the same way that nothing our size in its natural environment would be a threat to a kaiju. You have to be as big to be a threat, and as such suffer from the same neural delay.

There is no evolutionary reason to solve this problem.

or even to see it as a problem.

Answer 7

Your mega creatures can circumvent the issue of requiring large brains by having multiple smaller brains to handle multiple levels of tasks.

If each individual brain is only interested in its own specific function, ie keeping the digestive system going, or repairing damaged tissue, or movement, then the individual size would not need to be as large as you anticipate.

You would require a central processing unit, but this again could be relatively small, because it would only be required to coordinate the lower brains, and let them deal with the basics themselves, leaving it more energy for the higher functions, unless that is another level of brain again..

There would still be signal delay, especially between the individual brains, but this system could at least limit the need for longer-distance signals, and keep the possibility of higher function in at least one of the brains, if not more.

From an evolutionary standpoint, I can see this as a possible future path, as most animal brains are already compartmentalised to a large degree. Why not take it to its (il)logical extreme?

Answer 8

Because of [handwave], macro-creatures are slightly prescient, and begin reacting to stimuli before they happen

Instead of sending messages faster, why not have your giant creatures start reacting sooner? As in, sooner than the thing they're reacting to has happened. Sure, this is impossible based on our understanding of causality and physics. But so are (most) extremely large creatures, so you're already handwaving pretty hard.

The advantage of this, over some biological peculiarity merely allowing for faster transmission of messages, is that it comes with a built-in story hook. If once we figured out that giant creatures were breaking the laws of physics (in a potentially exploitable way!), you have a motivation to want to defeat the thing, but not kill it - at the same time that you've just made it very, very hard for the characters to actually accomplish it. (How do you beat something, without using overwhelming force, when it knows seconds or more before you've acted what you're going to do?)

Answer 9

The speed of thoughts

Let us consider the factors affecting the speed of thoughts

Neuron Size: Signals travel faster in neurons with larger diameters than those that are narrower.

Complexity: If more number of neurons are involved in a thought process, then absolute distance traveled by the signal is greater, which takes more time.

Myelin: The speed of the signal transmission is influenced by an insulating layer called myelin. Myelin is a fatty layer formed, in the vertebrate central nervous system, by concentric wrapping of oligodendrocyte cell processes around axons. Myelin speeds up conductivity and the transmission of electrical impulses and conduction velocity in axons.

So speed of thought may be increased by

• increasing neuron size.
• Less complex thought process.
• Myelination

Answer 10

Frame Challenge: True brain speed is measured in synapses, frequencies, temperature, and noise: distance over time is just an estimate based on human sized/shaped neurons.

Because we know the average length, diameter, and temperature of a human neuron we can estimate signal speeds in meters per second, but this is a gross over-simplification for the problem you are looking at. Assuming your megafauna is not also mega intelligent, it's 100m wide brain may not have any more individual synapses than other animals. The brain transmits data by electrochemical processes. The electrical part where the signals moves from one side of a neuron to the other happens at relativistic speeds. Since your cell is mostly made up of water and fats, this puts your Relative Permittivity at somewhere between 40-90 giving you a signal speed of ~47,000-32,000 km/s

The slow part of the process is the chemical part where an axon terminal waits until enough pulses of electricity are received to release a neurotransmitter which is a chemical that then has to react with the adjoining cell's dendrite to propagate the signal into the next cell. So, a larger brain with the same number of synapses will not be noticably slower than a smaller brain. In the human brain, neurons are typically about 6-100mm long... so in your megafaunna brain, those same neurons could be about 14-230 meters long. Such a cell would only take less than 0.000008 seconds longer to transmit an electrical signal from one end to another as the shorter human neuron.

Your mega fauna could actually think and react faster, not slower

The other big constraint with think time, is signal certainty. The tiny cells in your brain being all mixed together have to compete against signal lose and interference. In school, most of us learned that a Myelin Sheath is like a wire to make the signal go faster, but this is wrong. A Myelin Sheath is actually more like a series of capacitors designed to break up a continuous signal into discreate pulses of exact voltage and constrained frequency. This increases the clarity of the signal. With a more clear signal, the brain does not need to wait as long for a change in pattern to become obvious; so, the the synapse is able to begin reacting sooner. By making your neurons bigger, you have more space to spare to insulate your axion from outside interference and boost the actual signal strength. This means that a big brain can operate at higher frequencies without the signal becoming unclear which would boost how quickly synapses could respond to changes with a high level of certainty.

A typical human neuron operates at about 340±10Hz. This means we can only send a signal through about 34 neural connections per second based on how fast our sodium potassium pumps work. By increasing the cross-sections of the axions about 6500 fold, we now have up to 42 million times as much bandwidth as a human neuron. Not only can we use this added diameter to reduce interference, but using parallel axions like we see used in the auditory nerve, you can achieve frequencies in the megahertz or maybe even gigahertz range allowing MUCH faster response times in signal recognition. The chemical part of the neural connection may not be sped up at all, but speeding up the recognition system should make the recognition part of the system take about 0.03 seconds less time per synapse which would more than offset the extra time it takes the electrical signal to travel.

So, why do so many sources measure neural electrical speed in m/s?

In short, because it is easier to understand. Most authors don't understand/differentiate between the speed of the actual electricity and action potential propagation. As Austin pointed out in comments, a human neuron can send a signal at anywhere from 0.1-100 m/s. This very wide range of speeds is not proportional to ~50% electrical propagation speed differences between common organic compounds you find in the body.

Instead, it is affected by how long and wide the neurons are, how well it is designed to filter out noise, and how high of a frequency it can generate. At human sized neurons, even a Myelin Sheath can only do so much to filter out noise from adjacent cells meaning that even a longer cell needs more pulses to get a clear signal which effectively creates a speed-to-distance relationship (it's not 1:1, but it is a correlation) When you look at squid axions for example, they can achieve "faster" signals with thicker more distributed nerves for the kinds of neurons they have. You also see signals "slow down" at colder temperatures. However, electrons have less resistance in cold mediums, not more. This "slower" signal is because the chemical reactions of the sodium potassium pumps slow down reducing the frequency of the signal. If the electricity was only flowing at 0.1-100 m/s then a diameter higher diameter, warmer neuron would not increase the speed of the signal.

Answer 11

Neural fiberoptics

To truly increase the speed of neurons we can change how they work. We can use fiberoptics in the neurons instead of electricity.

Fiberoptics is a way to transmit light along transparent cables. As long as the bend in a cable isn't too large, it'll bounce all the way to the end. That means we can use this as a building block for fiberoptic neurons.

The neuron will have a bioluminous property. It can be off or change brightness. On the receiving end you have a photoreceptor like in the eye, but only a primitive highly sensitive version. This will translate the signal and stimulate it's own bioluminous organ.

This can be seen as a analogue signal, in contrast to the electric potential. Though stimulating a neuron is analogue, the electric potential is an on or off mechanism and thus digital. It can only transmit information via patterns. A fiberoptic neuron can thus put more information in a signal.

This can be further improved by adding different signals. Just like in our eyes we can select specific wavelengths that the neuron can perceive. If you have two or even more different receptors, you can add multiple wavelengths to a single neuron. As a quick example, a single neuron pathway can fire red, yellow and blue, allowing for 3 signals. More information at once!

The true improvement here is speed. The synaptic cleft is removed, which was the slowest part in transmission. It's function is replaced by the gradient of the light and the sensitivity of the receptor. In addition, the signal will go as fast as the speed of light, though a bit slower as it is still bouncing so not a straight line.

A fiberoptic neuron increases speed by insane amounts, is flexible, can handle more information per signal, can have multiple signals per strand, can't have electrical interference from itself, depending on the sensitivity can reduce enery cost and can reduce the amount of neurons required.

Answer 12

More brains.

In humans, our brain is constantly sending signals to the legs saying "left, right, left" and every other muscle movement that's required.

But, if you had a brain closer to the legs that was saying "Left, right, left", then your core brain need only say "Hey legs, start the left/right/left subroutine!" and then it can send any changes required like changes in direction when the eyes notice something, and just stop or starting to walk. This would be a very basic satellite brain.

Same for other areas of the body that usually rely on signals from regular signals from the brain.

Now, if your creature is so massive that waiting for a signal from the eyes to reach the primary brain, then sending a signal to the legs brain would be catestrophically slow, then it would be evolutionary advantageous to have secondary eyes near the legs, maybe even ears. Then, the legs could start working much more independently in terms of collision avoidance and path finding. The primary brain would more pass on a goal to the legs brain like "We want to go to this location that we've been to before", and the brain closer to the legs would take care of that.

An example of this would be octopi, which have a core brain, and eight ganglia (bunch of nerve cell bodies linked by synapses, like a mini bran) that can transmit information to each other without involving the central brain, making the ganglia more efficient.

Answer 13

Radio waves

Building on Monty Wild's idea of metal axons, is if the brains get big enough perhaps the axons begin to transition from being current bearing wires to radio oscillators. Instead of having one long axon the length of the brain you start having ones that act as dipoles. The brain would grow axons at different lengths (thus each axons signal would propagate at a different wavelength to reduce interference), then you would need a matching axon the other side of the brain and some handwaverium to turn the radio signal back into a useful neural impulse.

Answer 14

Farm the job out to Secondary brains

There's been some mention of octopi, with their arms having secondary brains that have some degree of independent decision-making.

But humans do this too!

We have the concept of muscle-memory and reflexes because our nervous system has extensive local clusters of neurons much closer to the limbs. These clusters can be trained to perform complex actions based on simple inputs from the main brain.

Some of these actions don't even need signals from the brain to be enacted. For example shoving away something extremely hot. The pain-signal from the hand reaches up to the local node, and is immediately responded to in-situ rather than going all the way up to the conscious brain and back.

Similarly while I'm typing this, I'm not consciously aware of the process of typing. my hands "know" where all the appropriate keys are for a given letter. I'm not even thinking about individual letters, I'm thinking Words and my hands know how to move to write the letters and clusters of letters far faster than my eye can follow and even process what I'm doing.

There are whole behaviours being farmed out to my secondary nerve-clusters which allow my brain, despite having a neural-lag of anywhere up to half a second, to perform high-speed and precise actions in a timely manner.

Back to what this means for Kaiju

I would expect to see more of that functionality, and likely a lot of it would be unconscious.

A Kaiju would necessarily be a creature of instinct and reflex.

If Godzilla stubs his toe, he isn't going to feel it for a few seconds but his leg still has to respond so he doesn't trip and fall.

I would imagine a kaiju would necessarily need local "inner ear" style gyroscopic-senses closer to its legs so that its secondary-brain clusters aren't relying on the ones in its head.

And then there's the challenge of coordinating leg-movements across hundreds of meters of body.

Godzilla needs to have a fairly extensive neural-cluster in his pelvis which can handle 90% of the no-brain work for his legs.

He needs to have quite extensive neural-tissue in his hands/arms so that when he touches something he shouldn't, he immediately lets go rather than continue to take damage for five or ten seconds.

It may be that part of the supernatural resilience of kaiju is because they have such sluggish pain-response they simply don't react to having chunks blown out of them.

Answer 15

An octopus has lots of nerves in its arms/tentacles. So many, that they basically have brains of their own. Have you ever heard of Alien Arm Syndrome? It is like that, but intentional. A gigantic creature would probably have a series of minor brains that can react before communicating to the central brain.

Answer 16

Any non-instantaneous communication will still have neural lag, and it will be a problem at a sufficiently large size. Maybe there's a point where you're satisfied with your creatures' size and the neural lag doesn't have a huge impact (such is the case for us humans), but if you want to solve the problem for ANY size, you need instantaneous communication.

Enter quantum entanglement.

Quantum-entangled neurons could communicate with one another instantaneously, independent of distance (at least while in the same universe). This allows for galaxy-sized brains without beaking the laws of physics as we know them (except for allowing quantum entanglement of course), and it has the funny side-effect of not requiring physically connected neurons to form a brain. One human-neuron-sized neuron in every galaxy, all of them quantum entangled, could indeed form a brain (or a mind I guess). How would that mind communicate with its body is another question altogether, but perhaps each neuron has one body with a nervous system just like ours, or all cells are quantum-entangled and you don't have a galaxy-wide being but rather a galaxy is actually a single being. Lots of weird stuff can happen!