Why are there so many different neurotransmitters if nerves only communicate in a binary action potential language?
I mean different kinds of nerves are united to only their similar kind, so what is the use of having so many different chemical 'languages'?
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If there were only one kind of transmitter how would cocaine produce a different effect than barbiturates?
It's so you can have different mututally exclusive signals without having a type of neuron for every one of these signals.
How does that work? Whether it's X transmitter or Y or Z, the neuron will only communicate either a 1 or a 0. You could literally just have two neurotransmitters for the entire body.
One* even
To elaborate that OP, think of a thalamo-cortical connection like a power source connecting to a TV screen. The TV is using a binary YES/NO electrical language, but the cords in it are insulated and coded different colors, despite all of them being copper on the inside. The copper core is the common interneuron mixture in your brain, while the color-coded wire insulation is, effectively, the utility of neurotransmitters and neuromodulating peptides. Organisms are just much more efficient at "insulating" signals and communicating in this way.
If the brain only used GABA and glutamate to initiate action potentials, it would not have the ability to contain and control its electrical signals, and would require substantially more differentiated cells with unique microbiological properties. Basically, thinking of the brain like a wet CPU doesn't work, because interneuron and glial cells are more similar to each other than the discrete inorganic metals, plastics, rubbers and forms of glass used in any mechanical computer.
Action potentials are not binary. When a neuron gets a stimulus, its potential goes up by some amount. There is an internal threshold that must be reached in order for a neuron to spike. This means that the output is binary, but the internals can be binary, linear, or even non-linear and thresholds for spiking can change with different neurotransmitter levels.
The brain does not communicate in 1s or 0s.
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> There are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired - this is the "ALL OR NONE" principle.
Output is called action potential, so all action potential is binary. Idk what the intraneural communication is called. Either way I was speaking of the interneural communication.
But in a TV the output is non-binary. What would be the point of non-binary input if the output is always binary?
Muh Evolution
>Output is called action potential, so all action potential is binary. Idk what the intraneural communication is called. Either way I was speaking of the interneural communication.
The action potential of a neuron may be binary, but calling that the "output" is misleading, because that ouput serves as the input to the next, and arguably more important event: the release of neurotransmitters at the synapse. And that event is not binary since the presence of various chemicals in the synapse will determine how the neurotransmitters act on the receiving cell, in some cases strengthening and in other cases weakening the activation strength.
That's why thinking of neurons like simple binary electric circuits is very misleading - it causes you to not recognize the importance of the synaptic environment in signal transmission.
They don't.
Look up paracrines and 2nd messenger systems.
If there only either is an output or not, how does that make the input for neighboring neurons non-binary?
A neuron either releases transmitters at the end of the axon or not.
Paracrines r cool n all but I'm talking about neurons in specific.
A neuron's output is binary. A neuron's input is not. Which part doesn't make sense?
So the only thing neurotransmitters do is just determine how valuable the info is from specific neurons? For example some neurons whose output uses X transmitter is more potent than neurons that use Y?
Like my point is - if the presynapse either only receives action potential or not, it cannot choose which transmitters to release. It can only either release them (in response to action potential) or not. So the only regulation transmitters seem to be able to do is not intracellular (such as a neuron picking the type of transmitter it would need to release in any specific situation) but more of a intercellular level regulation (ranking transmitters in a "potency hierarchy").
Do you feel me?
I feel like there's some major aspect missing, because as it is, it doesn't make much sense.
A neuron's input is the combination of outputs from other neurons, which is non binary
But the non-binary input is translated into a binary buildup of positive charge which either crosses the critical threshold or not. So where does the number of transmitters actually make a difference and in what way?
No shit there’s a major aspect missing. I know this is kind of shit posting but you clearly haven’t studied enough neuroscience to be making the authoritative, reductionist claims you’re making in this thread (the body could /literally/ function with two neurotransmitters). You asked a loaded question with an incorrect assumption, which is just going to make things more confusing for you than if you just had an open mind and stopped arguing your point and tried as hard as you could to understand the much wiser voices in this thread. I’m just being a faggot but damn you’re being stupider than you need to be, and you could learn a lot more a lot quicker.
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Not a single person here has actually explained why there are numerous transmitters. Everyone keeps just saying there are.
I know that. I'm asking why. Where does the difference come into play.
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So basically the point is to have some neurons be able to exclude other neurons, when activated?
So maybe becuase the only thing we can measure as a response is electrical activity.
Id imagine using dyes or radioactive isotopes tagged to different neurotransmitters would seriously fuck up the test subject qnd thus conflate readings.
Or data might be so jumbled to us it would appear like static on a tv. And you would need to sort through so much micro complexity.
what about instances in which neurons communicate in abnormal circumstances, like synthesizia or while one psychedelics?
Read the thread, most of the answers are making this much more complicated than it needs to be. Selectivity in the response of a neurotransmitter is not as important as selectivity in the production stimulus is, and for that you need neurotransmitters to be significantly different for mutually exclusive signal transduction.
Stimulus A produces neurotransmitter A and B produces B.. etc.
Neurotransmitter A and B perform the same action
Even if A and B have similar functions there needs to be a level of control over when each stimulus produces any response at all.
Yes, the question still remains: by what mechanisms can a neuron choose which transmitter in specific to release, if the only way it sends a signal to the presynapse is via binary action potential?
How can we answer this "why" question?
A counter question: why would it be any other way?
Threshold
For starters, neurons do not connect only to other neurons, they also connect to receptor and effector cells, like smooth and striated muscle cells, so they need different types of neurotransmitters. As to why a neuron-neuron interactions require different neurotransmitters, one of my guesses is that a signal moving past the synapse to the postsynaptic membrane can either propagate the signal by opening sodium channels or brake the signal by opening chlorine channels - maybe different transmitters are required here? I'd have to revise physiology but i know i knew the answer once
Adding to that, they also connect to pressure, temperature, nocyceptors(pain receptors) and basicaly all stimuli receptors
It is the pattern of neural activation that produces behavior, so a binary language could do the trick.
By what mechanism do neurons affect the type of transmitter that will get released if the only way they can send information down the axon is binary?
So some transmitters are more potent than others, thus requiring less input for continued neural activation?
But is there a way a neuron could control the type of transmitter it would release? Or are neurons only able to release one kind of transmitter and there being several types of neurons for all the kinds of transmitters?
But if the action potential coming down the axon is only binary, ie it either is or isn't, what determines if sodium channels are opened or chlorine channels?
That's the core of my confusion here.
You got a neuron, it will fire when it reach a certain potential (closer to 0).
There is different kind of receptors, pretty much most of them are ion channels
If a NT, say, GABA, is going on a GABA receptor, chlorine will flow into the neuron, increasing its potential (so the neuron will not fire)
Now if a NT go on a receptor that open sodium channel in the same neuron, it will reduce the potential, but because the neuron got it's potential increased by the Cl- channel before, the sodium might be not enough to trigger the firing
That's why shits that increase the potential of neurons are called inhibitor, because they reduce the ability of a neuron to fire
When you take a depressant drug, you basically increase the potential of your neurons, thus reducing the likelyhood of them firing, that's why those drugs reduce activity in the brain
Sorry for broken english
I understand how neurotransmitters work. Agonists, antagonists, it's all fine and dandy. What I don't understand, however, is if neurons are able to control what kind of neurotransmitter they release. Or is one neuron only able to release one specific kind of neuron? So like some neurons inhibit the activation of others while other neurons increase it?
The majority of neurons contain only one type of neurotransmitter. Basically, you can say that there's is inhibitory neurons and excitatory neurons.
So it's correct to say that some neurons inhibit the activation of others while other increase it.
You can also inhibit inhibitory neurons et cetera
Neurons can only OUTPUT one kind of neurotransmitter, but they can receive INPUT from different ones.
Inputs can be different: one inhibitory neurotransmitter may decrease the potential a lot, but for a short time. another may decrease it a little less, but for a longer time etc.
God damn this took forever but finally I got an answer. Thanks, fags.
Would it also be correct to say that the only differences between neurotransmitters stem from function (excitatory/inhibitory) and potency (ranking, basically, where some overwhelm others)?
Short answer: no.
Long answer: as with most things in biology, it depends. Here, it depends on the receptors available for the transmitter on the postsynaptic membrane. For instance, dopamine can have both excitatory and inhibitory effects, depending on the receptor(D1 vs D2).
And, to have a more broader view of a neuron and its complexity, picture it like this: the dendrites gather all kinds of signals, excitatory and inhibitory. All these determine a change in membrane potential in the body of the neuron. Here all the signals are quite literally integrated into a single amplitude. While this amplitude is above the threshold potential, the axon fires, translating the amplitude into a firing frequency. The impulses reach the end of the axon and determine a depolarization there. Therefore, the frequency is again integrated into an amplitude. Finally, this amplitude determines the amount of neurotransmitter released into the synapse.
To put it in terms of signal processing, the information is first amplitude modulated, then frequency, then amplitude again. It is hardly 1s and 0s. A lot of computation is carried out in the neuron itself.
>OP doesn't know frequency is another dimension of signaling
Outputs are 1 or 0.
Inputs are anything but binary.
Because it allows you to modulate what kinds of cells get to receive your signal. If there were only one type of excitatory/inhibitory neurotransmitter, then an excitatory neuron would just try to activate everything it's connected to.
I thought neurons had a cooldown period before they could shoot another signal that wouldn't change no matter what (due to physical limitations)? Is frequency really something that has any other effect than simply sending the same 1s more frequently? Like does it create a fundamentally different reaction than sparse activity? For example with low frequency, transmitter X would be released, while with a higher frequency, it would be Y instead?
Simply so that behaviors don't get mixed up, you don't want to fall asleep every-time you get scared.
You have a very bad understanding of the brain.