Check out my newest video about synaptic transmission to supplement this awesome video! kzitem.info/news/bejne/xKOZqYqwsop9a5g
@llkeeley
11 жыл бұрын
Watch the subsequent scene: 5.Synapse and Information Transfer to see how a post-synaptic neuron modulates primary incoming information to change its own output. Think of this happening between billions of neurons in the human brain and any given neuron is a single part of a network communicating with possibly hundreds or thousands of other neurons to make sense of what is happening to the person at any given moment and how they need to respond or ignore the information. Pretty marvelous!
@indirac.4010
10 жыл бұрын
An excellent video....just enough info as required by our syllabus...thank you!
@llkeeley
12 жыл бұрын
You are welcome. Happy to have helped.
@llkeeley
12 жыл бұрын
Thank you, glad you liked it.
@llkeeley
12 жыл бұрын
@2askaa Thank you, Happy to have helped.
@Brightangel001
10 жыл бұрын
Great Video, made sense, thanks
@Becca6296
7 жыл бұрын
Thank you! I liek this video a lot and none of the other tutorials had insecticide examples .
@GBart
11 жыл бұрын
It takes a minimum of three signals in a short period of time to cause the neuron to which the post-synaptic dendrite belongs to fire (assuming it was at resting potential originally), correct? So if you have a name or a word on the tip of your tongue, it might be because there's some neuron along the way that can't get enough sodium in it at one time to fire?
@GBart
11 жыл бұрын
Also, after firing, a neuron overshoots and takes on a negative charge, correct? So if two neurons are in close proximity and fire one after another, one will be positively charged while the other is negatively charged, correct? Might this be how axons and dendrites find each other to form new synapses?
@llkeeley
11 жыл бұрын
Because a post-synaptic neuron is providing one piece of information that is being integrated into the entire nervous network that is monitoring the overall condition of the organism.It sends its information many directions where it then gets modulated and integrated. If you suddenly had pain input (= danger), that might take precedence over hunger, sleep or sex. Otherwise, one of those might be of more interest than another.Any single synapse is part of an extensive sensory-behavioral network
@urwaimran1487
7 жыл бұрын
Really helpful. Thank you.
@llkeeley
11 жыл бұрын
If you turned on a synapse and it never turned off you would continue to get information that was no longer relevant to the situation. Ex 1. if the synapse was part of a danger pathway for fight or flight, once the danger was over you would want the signal to end otherwise, you be constantly responding to a non-threat which in itself could be destructive. Ex. 2 If you contract a muscle you want to be able to relax it. Otherwise you are locked in tetany and could not move.
@4amiables
12 жыл бұрын
the video is right on point...great job. thanks a lot.
@dermc3491
2 жыл бұрын
Is the information coded in the frequency of that action potential or also in the amplitude ? Like an analogue signal traveling from a microphone to an amp to speakers ? How is decided which chemical (serotonine, adrenaline etc) is released and how much of it and in which time ? The gap fbetween neurons maybe similar to a transitor ?
@llkeeley
2 жыл бұрын
Action potentials are all-or-none so they do not show amplitude variations, and hence individually carry no information. The synaptic information is frequency of APs. Think of dots and dashes being the code of Morse code. The dots and dashes carry the code which is the frequency and patterns of the dots and dashes, and they convey the message. Different post-synaptic neurons release one or sometimes several, specific neurotransmitters. This is neuron-specific. The amount and time of response are determined by the number of input APs by the presynaptic neurons, and how far apart any incoming volleys of APs would be. I cannot answer your last question, as I do not know how transistors work.
@ungell
12 жыл бұрын
Wow. So does this mean that a charge is built up by the Na+ ions entering the Post synaptic dendrite? Furthermore, does the charge contain the information from the pre synaptic axon? How is information traveling from one neuron to another? I understand that the Na+ ions cause the reaction but is the information traveling within the Na+ element?
@llkeeley
12 жыл бұрын
Possibly yes. By convention current flow is in the direction of cation migration, and the membrane outside/inside polarity reverses. Since the active events of synaptic communication occur on the surface of the post-synaptic membrane, I wanted to keep the focus on the outside becoming more negative rather than the inside more positive. Maybe a better way would have been to simply say the membrane becomes increasingly depolarized proportional to the amount of neurotransmitter.
@paulafrengul9761
9 жыл бұрын
Amazing video, helped a lot. Thank you.
@llkeeley
11 жыл бұрын
Maybe? Sodium ions (Na+) are always positive. The receptor is part of the Na-channel structure (a protein). When dopamine binds the receptor the channel protein reconfigures to open and allow Na+ to enter the cell and reverse the membrane charge to (-) causing the neuron to respond. W/o the receptor the channel will not open. Also the neuron must connect to part of the brain that is involved with emotions. Not just any neuron anywhere. The receptor may be there in a less active mutant form?
@llkeeley
11 жыл бұрын
I don't see this as a big jump. If you have an on-switch (neurtransmitters) it seems logical to provide an off-switch (degradative esterase) otherwise, once on -- always on, which would be counterproductive for meaningful signaling. Esterases are pretty common and having one work on AcCh (an ester) would seem quite selective for survival. Other non-ester neurotransmitters (serotonin, dopamine etc.) are removed by re-uptake by the pre-synaptic neuron.
@FUCKUSATURN
11 жыл бұрын
I have never heard of positive sodium ions before. So it's not really the dopamine attaching that give us pleasure, it's the membranes getting negatively charged from the ions? So if one were to have severe stubborn Anhedonia (me...) due to desensitized or no receptors, they could just find a way to stimulate or charge the membrane......?
@camuga3222
4 жыл бұрын
This helped me a lot, thanks
@llkeeley
12 жыл бұрын
You are welcome. Happy to be of assistance.
@cosmonaut42
11 жыл бұрын
wonder there is some imbalance in release of D2 in Schizophrenia DISC1 gene and may be the enzyme to disrupt neurotransmitter fails in those cases of cognition and anxiety...
@llkeeley
12 жыл бұрын
A Na ion by itself has no capacity to convey information. The number of Na ions entering is related to information, and determines the size of the post-synaptic depolarization. For a more complete review of information coding please watch my video Neurons, Synapse and Information Transfer which describes how each part of the nervous system detects, codes and transfers information. It is based on insects, but is true of vertebrate animals too.
@carlagalbiati3250
Жыл бұрын
Excelent exposition and dynamic animation.
@llkeeley
Жыл бұрын
Thank you
@GBart
11 жыл бұрын
At least it makes sense to me that way, since if we call these two neurons A and B, and A often fires just before B does, then A will begin to signal B in anticipation, hence a simple pattern is learned.
@sssuheylaaa
11 жыл бұрын
very good explanation...thanks
@kiranbudhvat3642
8 жыл бұрын
nice information
@1000nateriver
10 жыл бұрын
thanks but can you explain why there is a synaptic gap and why it's necessary? I mean would i t be fine if we dont have the gap and everything is connected?
@llkeeley
10 жыл бұрын
Excellent question! There are, in fact, two types of synapse: chemical synapse (depicted here) and electrical synapse, as you suggest. Electrical synapse are two neurons connected by "gap junctions" and the impulse (action potential) in one is transferred to the other 1:1 so that the two neurons act as a unit. This is found in neuronal networks. Action potentials are all-or-none so a single impulse does not carry much information, but their information is based on their frequency (APs/unit time). Chemical synapse are more common and the chemical and gap allow for more flexibility. A quanta of neurotransmitter (NT) chemical is released into by the presynaptic neuron in response to each incoming AP, and the NT may need to accumulate in the gap to certain levels to induce a postsynaptic response. These levels neuron-specific. Also, I would speculate that the biggest value of the chemical synapse lay in its capacity to have a variety of chemicals that can serve as NTs. This allows for a great deal of flexibility as to the specific neurons that respond. We know that different neuronal complexes convey different messages, and many of these actions are NT-specific. The chemical would have to work through a gap. Actually, a given post-synaptic neuron could synapse with a number of different presynaptic neurons and respond differently to all of them, if they use different NTs. For example, some post-neurons are activated by AcCh, but inhibited by GABA. Remember -- the gap is very narrow so the effect is quite localized on the surface of the receiving dendrite, and the response is a graded depolarization.
@LAMOOproductionsLAMEGUYHERE
8 жыл бұрын
the synapse maintains one way flow of the nerve impulses
@2askaa
12 жыл бұрын
this is a really good video thanks for sharing xxx
@KellyWillox
12 жыл бұрын
very good
@ArsiniC11
5 жыл бұрын
I thought neurotransmitters get re-uptaken into the pre snynaptic axon hence the term SSRI (Selective Serotonin Reuptake Inhibitors)
@llkeeley
5 жыл бұрын
Some like serotonin, dopamine and other small molecules are taken up for reuse. Acetylcholine is degraded to acetate and choline and then, these can be taken up and used for AcCH re-synthesis.
@ArsiniC11
5 жыл бұрын
@@llkeeley gotcha, thanks
@CrystalGil
8 жыл бұрын
great video thanks for posting
@kabujemitiness2674
6 жыл бұрын
Crystal Gil OK good my friend
@SalmaNawati
9 жыл бұрын
helpful thank you a lot
@Komelsky
12 жыл бұрын
I find the term "Negative depolarization" to be is extremely confusing. Yes, theoretically you can say that the "outer side of the membrane becomes negatively charged" (you say that around 3:00), meaning that it is charged negatively relative to the inside of the cell. But why not sticking to the fact that positive ions charge the inside of the cell positively? Is not it much more intuitive way to describe this process?
Пікірлер: 60