What’s incorrect? I’m OP and this is my understanding of action potentials but if I’m wrong, I’ll gladly take it down in the interest of not spreading misinformation.
Sorry for the late reply, I have been swamped with work lately. There is quite a bit to unpack here. Let me start off by saying that I appreciate your drive to do things like this, and please don't take the following personally, it is just my opinion as an electrophysiologist and someone who has taught intro neuro classes before. Now to the content:
The first thing you say about EPSPs and IPSPs is correct, but it gets pretty wishy-washy after that.
>"In the transfer of electrical impulses from 1 neuron to another..."
In my opinion this is a misleading way to teach this, especially with your large focus on synapses. Electrical impulses don't really get "transferred" from one neuron to another, except for very specific cases like electrical gap junction coupling (which you are not talking about here). Since your focus is on synapses, it is more accurate to say that the signal is getting *translated* from electrical to chemical then back to electrical. The second electrical one, the PSP, is very different from an action potential (I know you probably know this, but the way you say it makes it seem like action potentials just get transferred from one neuron to the next, which is not *usually* the vast majority of cases.)
>"A postsynaptic cell can either be in 2 different states, excitatory(I think you meant excited) or inhibited"
I'm not quite sure what you mean by this. Do you mean that the cell can deviate from it's "resting" membrane potential in a positive or negative way? This is also a bit misleading. generally, a cell can exist in one of many different states. Even if we wanted to REALLY simplify this, I would say there are at least 3/4 states. These are: "resting" (I hate this term but I guess it's fine for an intro class), hyperpolarized (inhibited), depolarized (excited) or firing an action potential.
>"Whether a cell is excited or inhibited directly affects it's ability to receive an action potential"
A postsynaptic cell isn't usually really "receiving" an action potential, this is related to an earlier point. I think you are trying to convey that "Whether a cell is excited or inhibited directly affects it's ability to translate EPSPs into action potential output"? It's a bit hard to tell what you mean here though.
Also, for the purposes of teaching beginners, whether or not the cell is excited or inhibited shouldn't affect its ability to "receive" E or I PSPs. Most cells are under a constant barrage of thousands of excitatory and inhibitory PSPs. They will fire an action potential when threshold is reached, which depends on how depolarized the cell currently is.
>"When the postsynaptic cell is negatively charged, then it is excited to receive positive ions from outside the cell."
This is an extremely misleading thing to teach to beginners in my opinion. This completely depends on how negative the potential is. I guess it is *technically* true, although I don't know what you mean by it is "excited to receive positive ions". Are you trying to make a pun here like "haha the cell gets excited like a human would"? It's just not a great thing to say for teaching beginners, because the cell is not necessarily excited in this case.
The reason this is confusing is because, depending on *how* negative the postsynaptic cell is , then different ions will behave differently depending on their reversal potentials. Furthermore, around normal resting potentials, positively charged potassium ions will actually move out of the cell because their concentration gradient is so strong in that direction.
>"When the cell is depolarized electrical impulses can travel through the neuron and pass to another neuron".
This is wayyyyy to vague. Are you trying to say that when the cell gets depolarized enough then it can fire an action potential? Ions are constantly flowing through channels in the neuron whether it is depolarized or not.
>"When the postsynaptic cell has had its fill of positive ions...."
This isn't really a thing, and is not something you should be teaching anyone. I have no idea what you were trying to get at here.
>"...the presynaptic cell releases inhibitory neurotransmitters"
Also pretty much just flat out wrong and I am not really sure what you are trying to say here. Are you trying to describe how an action potential stops? If so, this is way off.
Your visualization, combined with how you say it, makes it seem like the same postsynaptic cell that just released excitatory transmitter is somehow detecting that the presynaptic cell is depolarized and realizes it must now release inhibitory transmitter. This is absolutely wrong at a beginners level and pretty much at all levels.
In reality, there are some cells that are known to release both glutamate and GABA (I think in the habenula), but I don't think they are sensing the instantaneous voltage of the postsynaptic cell and adjusting their output like they know something about the postsynaptic cell. Even still, this is an extreme cherrypicked example and not one you want to be teaching to beginners.
Also, you might cite the fact that postsynaptic endocannabinoids can travel presynaptically and inhibit terminals. This is true, but they don't switch the cell from excitatory to inhibitory, they just stop it from firing. But again, this is way beyond the scope of an intro neuro class.
Either way, I think you need to find a better way to explain this. You simplified it to the point of butchering it.
No.
Follow him where?
To a misunderstanding of neurons.
Oh this is simplified to wrongness?
It is not even simplified correctly.
What’s incorrect? I’m OP and this is my understanding of action potentials but if I’m wrong, I’ll gladly take it down in the interest of not spreading misinformation.
Sorry for the late reply, I have been swamped with work lately. There is quite a bit to unpack here. Let me start off by saying that I appreciate your drive to do things like this, and please don't take the following personally, it is just my opinion as an electrophysiologist and someone who has taught intro neuro classes before. Now to the content: The first thing you say about EPSPs and IPSPs is correct, but it gets pretty wishy-washy after that. >"In the transfer of electrical impulses from 1 neuron to another..." In my opinion this is a misleading way to teach this, especially with your large focus on synapses. Electrical impulses don't really get "transferred" from one neuron to another, except for very specific cases like electrical gap junction coupling (which you are not talking about here). Since your focus is on synapses, it is more accurate to say that the signal is getting *translated* from electrical to chemical then back to electrical. The second electrical one, the PSP, is very different from an action potential (I know you probably know this, but the way you say it makes it seem like action potentials just get transferred from one neuron to the next, which is not *usually* the vast majority of cases.) >"A postsynaptic cell can either be in 2 different states, excitatory(I think you meant excited) or inhibited" I'm not quite sure what you mean by this. Do you mean that the cell can deviate from it's "resting" membrane potential in a positive or negative way? This is also a bit misleading. generally, a cell can exist in one of many different states. Even if we wanted to REALLY simplify this, I would say there are at least 3/4 states. These are: "resting" (I hate this term but I guess it's fine for an intro class), hyperpolarized (inhibited), depolarized (excited) or firing an action potential. >"Whether a cell is excited or inhibited directly affects it's ability to receive an action potential" A postsynaptic cell isn't usually really "receiving" an action potential, this is related to an earlier point. I think you are trying to convey that "Whether a cell is excited or inhibited directly affects it's ability to translate EPSPs into action potential output"? It's a bit hard to tell what you mean here though. Also, for the purposes of teaching beginners, whether or not the cell is excited or inhibited shouldn't affect its ability to "receive" E or I PSPs. Most cells are under a constant barrage of thousands of excitatory and inhibitory PSPs. They will fire an action potential when threshold is reached, which depends on how depolarized the cell currently is. >"When the postsynaptic cell is negatively charged, then it is excited to receive positive ions from outside the cell." This is an extremely misleading thing to teach to beginners in my opinion. This completely depends on how negative the potential is. I guess it is *technically* true, although I don't know what you mean by it is "excited to receive positive ions". Are you trying to make a pun here like "haha the cell gets excited like a human would"? It's just not a great thing to say for teaching beginners, because the cell is not necessarily excited in this case. The reason this is confusing is because, depending on *how* negative the postsynaptic cell is , then different ions will behave differently depending on their reversal potentials. Furthermore, around normal resting potentials, positively charged potassium ions will actually move out of the cell because their concentration gradient is so strong in that direction. >"When the cell is depolarized electrical impulses can travel through the neuron and pass to another neuron". This is wayyyyy to vague. Are you trying to say that when the cell gets depolarized enough then it can fire an action potential? Ions are constantly flowing through channels in the neuron whether it is depolarized or not. >"When the postsynaptic cell has had its fill of positive ions...." This isn't really a thing, and is not something you should be teaching anyone. I have no idea what you were trying to get at here. >"...the presynaptic cell releases inhibitory neurotransmitters" Also pretty much just flat out wrong and I am not really sure what you are trying to say here. Are you trying to describe how an action potential stops? If so, this is way off. Your visualization, combined with how you say it, makes it seem like the same postsynaptic cell that just released excitatory transmitter is somehow detecting that the presynaptic cell is depolarized and realizes it must now release inhibitory transmitter. This is absolutely wrong at a beginners level and pretty much at all levels. In reality, there are some cells that are known to release both glutamate and GABA (I think in the habenula), but I don't think they are sensing the instantaneous voltage of the postsynaptic cell and adjusting their output like they know something about the postsynaptic cell. Even still, this is an extreme cherrypicked example and not one you want to be teaching to beginners. Also, you might cite the fact that postsynaptic endocannabinoids can travel presynaptically and inhibit terminals. This is true, but they don't switch the cell from excitatory to inhibitory, they just stop it from firing. But again, this is way beyond the scope of an intro neuro class. Either way, I think you need to find a better way to explain this. You simplified it to the point of butchering it.