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What he means is a -10 mV change in the voltage, not that it is a threshold. The threshold is still -55 mV, so the EPSP or IPSP will either excite or inhibit the neuron from firing by bringing it closer or away from doing it, respectively.
The threshold is inversely proportional to the density of VG Na+ channels. It is not constant. The threshold at the dendrite area is relatively higher.
Sir. Please clarify this point.. If every neuron - neuron synapse has inhibitory post synaptic potential. So if an action potential has passed through neuron, it will inhibit now for another action potential? If this phenomenon is for every neuron- neuron synapse ? And for every neuron - muscle synapse there is excitatory post synaptic potential. If its so, whats the benefit of that ? Could you explain please.. Thank you..
Not exactly. It's the action that Neurotransmitter causes. For example, some (many) neurotransmitters create both:- Inhibitory effects in some cases, while excitatory effects in other. Thus, what is more important is the type of Receptor for the corresponding neurotransmitter released. . So, to be precise, it is the excitatory or inhibitory effect of a Neurotransmitter that is finally going to cause the change. (So, a Neurotransmitter that only causes inhibitory effect will always bring the membrane potential down in all Synapses. While a Neurotransmitter like Dopamine or Serotonin will Excite the PSN(post synaptic neuron) in some places (where Dopamine/Serotonin receptors are excitatory) while Inhibiting PSN in the other places (in synapses with inhibitory DA/HT2A Receptors .)
MURDR63 the receptor would somehow trigger sodium channels to open, which depolarizes the membrane potential of the neuron, crossing the threshold to trigger the first action potential. You somehow have to take a stimulus and make it open ion channels which will start the first action potential.
Because here it was starting of entry of neuro transmitter in membrane so before action potential formed here at neuron outer na ions are equal to inner cl ions so negetive so becomes equal so it was 0
Nope. That's not how it works. Think about this only in terms of Synapses (the connection). Imagine yourselves trying to approach a girl. Some friends are pulling you behind (discouraging you because your hair looks bad at that moment) -- Inhibitory impulse. While others are encouraging you (because that jacket you are wearing is cool af) - excitatory impulse. Any Single connection could act as a pulling or pushing unit. When finally encouraged enough (given 4 out of 5 friends are pushing you for action), you might gather enough courage and motivation to finally get over your inhibitions (the negative resting state potential that keeps you From taking any action) to go and ask her out. . Considering you. You might primarily be accompanied by Positive features at that moment. (Nice jacket, great cologne, Good speaking skills etc... Maybe a negative Hairstyle. But you can workout around using so many positive (excitatory signals). So you talk to her, and continually fire excitatory signals to make her Excited enough to reach her action potential and she lends her number to you. And also TAKES ACTION to ask her friend to click a picture of you and her together. On the contrary, if you were a Negative guy - who inhibits other girls from taking action (due to bad hair, bad breath, bad conversation skills etc... Every signal inhibitory), you would go, and depolarize the girl and she would be TURNED OFF, and no number for you, sorry! So, what happened was, many Excitatory neurons excited You (a neuron primarily Populated with more number of Inhibitory Neurotransmitter/Post Synaptic Receptor pairs), so you were able to TAKE ACTION. The inhibitory neuron then took Action and signalled the Next Neuron (third layer neuron). But since the primary signal was inhibitory, the Next Neuron was primed to NOT TAKE AN ACTION Forward. (P.S. a neuron or a Neurotransmitter are not primarily Inhibitory/Excitatory. It's the signalling that determines the Interaction. For e.g You wearing specs with a nerdy look might be a Turn On for one woman while vice versa for other. --( although we all know the popular opinion :p). Similarly a Neurotransmitter like Dopamine might act to excite a Neuron with DA1 receptors, while Inhibiting a Neuron/Synapse with a DA2 receptor. (DA=Dope Amine))
@@tsaed.9170 I can see how an EPSP increases the firing in excitatory neurons. But if EPSPs increase the firing chance in inhibitory neurons (like excitatory neurons by exceeding a threshold), then a (negative) inhibitory action potential is released to the axon (when the membrane potential surpasses -10mV). So for the same depolarization of membrane potential (4cawmi2va33i3w6dek1d7y1m-wpengine.netdna-ssl.com/wp-content/uploads/2018/12/3.1_Understanding-your-brain.jpg), the inhibitory neurotransmitters in inhibitory neurons carry a negative pulse while the excitatory neurotransmitters carry a positive pulse?
Well, actually the threshold is not necessarily -55 mV or - 10 mV. It depends on many factors. I will make a video on it and explain this in more detail for you. Thank you for your comment.
