Side note: OFF center bipolar cell receptors have sodium channels. If they were potassium channels, binding of glutamate would cause hyperpolarization and a lack of glutamate would cause depolarization. But it wouldn’t depolarize when there’s lack of glutamate because it’s an OFF center cell.
They are non NMDA receptors as opposed to metabotropic glutamat receptors on on center that is why binding of glutamat can result in two different outcomes
I didn’t know that the bipolar cells contained different receptors; but, now that I’ve learned it from you, everything is way more clear to me. This is the BEST. Thank you
You can't possibly understand how the vision system works unless you consider the fact the this isn't about static images. The retina is designed to detect more than just light/dark and edges. It's all about detecting movement and that's all a matter of temporal processing which is left to the brain and I think that deserves a brief mention here.
An exceptionally well explained video! I had my difficulties understanding it when it came up in my neuroscience course but now I can finally grasp the meaning! Thank you!!
1. ON Bipolar Cells Receptors on Dendrites: Metabotropic Glutamate Receptors (mGluR6): Type: mGluR6 is a metabotropic (G-protein-coupled) receptor. Function: In the dark, glutamate released from photoreceptors binds to mGluR6 receptors on ON bipolar cells. This activation leads to the closure of TRPM1 cation channels, causing the cell to hyperpolarize (become more negative inside). In the light, decreased glutamate release leads to less activation of mGluR6 receptors. This allows TRPM1 channels to open, leading to depolarization (cell becomes more positive). Neurotransmitter Released from Terminals: Glutamate: Function: ON bipolar cells release glutamate when depolarized (in response to light). Targets: They transmit signals to ON-center ganglion cells, conveying information about increases in light intensity. 2. OFF Bipolar Cells Receptors on Dendrites: Ionotropic Glutamate Receptors (AMPA and Kainate Receptors): Type: These are ionotropic receptors that directly control ion channels. Function: In the dark, glutamate from photoreceptors binds to these receptors on OFF bipolar cells. This causes cation channels to open, leading to depolarization. In the light, decreased glutamate results in fewer open cation channels, causing the cell to hyperpolarize. Neurotransmitter Released from Terminals: Glutamate: Function: OFF bipolar cells release glutamate when depolarized (in response to darkness). Targets: They transmit signals to OFF-center ganglion cells, conveying information about decreases in light intensity. 3. Horizontal Cells Receptors on Dendrites: Ionotropic Glutamate Receptors (AMPA and Kainate Receptors): Type: Similar to those on OFF bipolar cells. Function: In the dark, glutamate from photoreceptors binds to these receptors on horizontal cells. This leads to depolarization of horizontal cells. In the light, decreased glutamate causes horizontal cells to hyperpolarize. Neurotransmitter Released from Terminals: GABA (Gamma-Aminobutyric Acid): Function: Horizontal cells release GABA, an inhibitory neurotransmitter. Targets: They provide inhibitory feedback to: Photoreceptors: Modulating glutamate release and contributing to lateral inhibition. Bipolar Cells (indirectly): Influencing the input that bipolar cells receive from photoreceptors.
Thank you so much Sarah, I have an exam in two weeks and my professor has tried over 10 times to explain this to me but I couldn’t get it. I even read the book that you picked up your slides from and didn’t understand but with you explanation I just GET IT!!!! Thank you so much 🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻
Thank you for the amazing explanation. I found one mistake about the glutamate receptor on the Off-center bipolar cell. (1:40-1:45) As others have already pointed out, this is not a K+ channel, but a channel for general cations such as Na+. So that when the channel opens, K+ does not flow out, but Na+ flows in, resulting in depolarization. Thank you.
Thank you so much! I have understood the lateral inhibition and the off and on center thing before hand but never managed to connect them! Thank you so much!
Hello! Great video, thank you. 1:43 Why does the cell depolarize when potassium is flowing out of the cell? (potassium is positively charged, so shouldn't it hyperpolarize?)
Potassium channels indeed lead to hyperpolarization of the cell. Glutamate activates AMPA receptors (Na+/K+ permeable) in the off bipolar cells, instead of potasium channels. These AMPA receptors lead to depolarization of the bipolar cell.
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@Marcellus Kellen I really appreciate your reply. I found the site thru google and I'm trying it out atm. Seems to take quite some time so I will get back to you later when my account password hopefully is recovered.
I have to know this crap for my Introduction to Psychology uni course. I’m only a freshman undergrad & I’m just so confused lol. This is very advanced biology material... I hope I’ll get the gist of it soon. Pray for me and my fellow confused psych peers 😭
Thanks so much, it helped me so much, even though it was in english. So much better than how our prof tried to explain it to us, I didn't understand a word back then :D
Sarah the way you explained this slide was amazing, very easy to follow along and you made it much easier to understand. you should keep going with those videos, Especially since 70k views mean that most of us don't really understand this topic and might actually do well on our exams thanks to you! :)
On center is having mGluR which is activated by low conc. Glutamate where as surrounding zone is having ionic GluR which is sensitive to high conc glutamate ....Less glutamate activates mGluR so more depol. at BPC as well as GC in on-center off-surroundings where as in opposite case when center is dark, more glutamate releases due to Hyperpol. and it acts on Ionic GluR so depolarisation occurs at BPC, GC....leading to Off center on surrounding situation..😊
Thanks a lot for your explanation! I also have a question, just to be completely sure: Can we say that we have ON-center-OFF-surround and OFF-center-ON-surround receptive fields in both bipolar cells AND retinal ganglion cells? :)
It’s due to the amacrine cells that act to (partially) inhibit the central retinal ganglion cells. It’s not a strong enough stimulus from these amacrine cells to completely negate the output, however it reduces the firing rate of these neurones.
I have a question and i have searched all internet for this haha. But the space above and bellow spontaneous activity is Asymmetrical. So when switching light off the spontaneous activity van only drop so much before it reaches 0. This is a problem (i don't really understand why)? And that's one of the reasons why the cells have an on and off center, because of the asymmetry. But i don't really get how the on and off center help with this
depends, as an opthamologist myself i can tell you there are different types of horizontal cells that secrete different nt, but the effect is inhibition, there are 30 or so amacrine cell types and at least 3 ganglion cell types in humans
Hi Sarah, first thanks a lot for making this great vid I have couple of question: 1. how are those rf connected to the different types of cells(simple complex and hypercomplex cells) is it that several of those rf connected to same cell in the visual cortex? 2. how are the different types of rf formed? as i understood we have 4 types yellow on-blue off, blue on-yellow off, red on-green off and green on-red off? if we only have red blue green cones? thanks again :)
Yellow is a combination of Red and Green! (counter-intuitive, I know!) Receptive fields are formed by neighboring fields of red surrounding green, red and green around yellow, etc. Several receptive fields do map on to single cells in the visual cortex!
This is above the scope of psych 100 right? I don't know if I'm going to fail my test or trying to learn something too advanced for my class. Is this necessary for the perception and sensation chapter of first year psychology
Nah. You don’t need it for 100’s psych, I would guess. All I knew for that class about photoreceptors was cones=color perception, rods=brightness perception. Hope you didn’t fail though
The default state of photoreceptors is depolarized in the dark (aka dark current). When light hits the photoreceptors it shifts the conformation of rhodopsin, leading to activation of a G protein pathway that degrades cGMP. cGMP is what keeps sodium ion channels open in the photoreceptors, so when you have less cGMP, the channels close and the cell hyperpolarizes.
Could you please make a video explaining what that "patch of retina" in the upper left corner "is"? Are ganglion cells really microscopic little circles surrounded by a bigger circle which in turn is surrounded by a patch or retina? I thought that these "circles" were mere abstract representations of the visual field (in a sort of topographic map), as I learned from this video: ruclips.net/video/oBJSG15Nq2E/видео.html
You explain clearer in 6.5 mins than my prof in half an hour QAQ Thank you for saving me!
Side note: OFF center bipolar cell receptors have sodium channels. If they were potassium channels, binding of glutamate would cause hyperpolarization and a lack of glutamate would cause depolarization. But it wouldn’t depolarize when there’s lack of glutamate because it’s an OFF center cell.
But everything else is good pls i rlly feel like it is can u confirm all but that sounds perfect amazingly explained
They are non NMDA receptors as opposed to metabotropic glutamat receptors on on center that is why binding of glutamat can result in two different outcomes
Out of nowhere this has to be the most lucidly explained video missing its whole playlist
This is the clearest explanation I've ever heard
I didn’t know that the bipolar cells contained different receptors; but, now that I’ve learned it from you, everything is way more clear to me. This is the BEST. Thank you
unfortunately for students guyton's physiology doesn't have this information
Sarah Freeman, from the deepest of my heart, thank you.
Thank you! This has finally made sense to me!!
You can't possibly understand how the vision system works unless you consider the fact
the this isn't about static images. The retina is designed to detect more than just light/dark
and edges. It's all about detecting movement and that's all a matter of temporal processing
which is left to the brain and I think that deserves a brief mention here.
An exceptionally well explained video! I had my difficulties understanding it when it came up in my neuroscience course but now I can finally grasp the meaning! Thank you!!
About time this was explained correctly and in just the right amount of detail. Subscribed.
thank you so much! I have been reading this topic in my books for hours but now I finally understand it, thank you!
1. ON Bipolar Cells
Receptors on Dendrites:
Metabotropic Glutamate Receptors (mGluR6):
Type: mGluR6 is a metabotropic (G-protein-coupled) receptor.
Function: In the dark, glutamate released from photoreceptors binds to mGluR6 receptors on ON bipolar cells.
This activation leads to the closure of TRPM1 cation channels, causing the cell to hyperpolarize (become more negative inside).
In the light, decreased glutamate release leads to less activation of mGluR6 receptors.
This allows TRPM1 channels to open, leading to depolarization (cell becomes more positive).
Neurotransmitter Released from Terminals:
Glutamate:
Function: ON bipolar cells release glutamate when depolarized (in response to light).
Targets: They transmit signals to ON-center ganglion cells, conveying information about increases in light intensity.
2. OFF Bipolar Cells
Receptors on Dendrites:
Ionotropic Glutamate Receptors (AMPA and Kainate Receptors):
Type: These are ionotropic receptors that directly control ion channels.
Function: In the dark, glutamate from photoreceptors binds to these receptors on OFF bipolar cells.
This causes cation channels to open, leading to depolarization.
In the light, decreased glutamate results in fewer open cation channels, causing the cell to hyperpolarize.
Neurotransmitter Released from Terminals:
Glutamate:
Function: OFF bipolar cells release glutamate when depolarized (in response to darkness).
Targets: They transmit signals to OFF-center ganglion cells, conveying information about decreases in light intensity.
3. Horizontal Cells
Receptors on Dendrites:
Ionotropic Glutamate Receptors (AMPA and Kainate Receptors):
Type: Similar to those on OFF bipolar cells.
Function: In the dark, glutamate from photoreceptors binds to these receptors on horizontal cells.
This leads to depolarization of horizontal cells.
In the light, decreased glutamate causes horizontal cells to hyperpolarize.
Neurotransmitter Released from Terminals:
GABA (Gamma-Aminobutyric Acid):
Function: Horizontal cells release GABA, an inhibitory neurotransmitter.
Targets: They provide inhibitory feedback to:
Photoreceptors: Modulating glutamate release and contributing to lateral inhibition.
Bipolar Cells (indirectly): Influencing the input that bipolar cells receive from photoreceptors.
This was wo well explained, better than all of the books
Thank you so much Sarah, I have an exam in two weeks and my professor has tried over 10 times to explain this to me but I couldn’t get it. I even read the book that you picked up your slides from and didn’t understand but with you explanation I just GET IT!!!! Thank you so much 🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻
Thank you for explaining such a hard topic better than most books, and in 6min ;) Finally got it
this is such a great explanation, helped me with a test a few weeks ago and is helping me with my final exam once more!! thanks Sarah :)
Thank you for the amazing explanation. I found one mistake about the glutamate receptor on the Off-center bipolar cell. (1:40-1:45) As others have already pointed out, this is not a K+ channel, but a channel for general cations such as Na+. So that when the channel opens, K+ does not flow out, but Na+ flows in, resulting in depolarization. Thank you.
This is the best explanation on RUclips
Hey! This Part always confused me during my studies and you did an amazing job explaining it!
I would Make LOVE to this video. Thank you for your service.
Update: My wife is now three weeks pregnant. Thank you Sarah Freeman!
You are an absolute legend! My 40 minute lecture was simplified in 6 minutes!
absolutely brilliant explanation, this was really confusing me for a while but makes perfect sense now! thank you so much!
Thank you so much! I have understood the lateral inhibition and the off and on center thing before hand but never managed to connect them! Thank you so much!
Great explanation, I have been stuck on this topic for the past three days!
Hello! Great video, thank you.
1:43 Why does the cell depolarize when potassium is flowing out of the cell? (potassium is positively charged, so shouldn't it hyperpolarize?)
Potassium channels indeed lead to hyperpolarization of the cell. Glutamate activates AMPA receptors (Na+/K+ permeable) in the off bipolar cells, instead of potasium channels. These AMPA receptors lead to depolarization of the bipolar cell.
She made a mistake. Those are the usual AMPA Na+ Channel Classic.
Massive thank you!!! It took me hours to understand this by my own even reading books about it, but you just made it look so easy!
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@Erik Boone instablaster =)
@Marcellus Kellen I really appreciate your reply. I found the site thru google and I'm trying it out atm.
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Very well made video - explanations were very good & was an excellent supplement to the textbooks I was reading through
Thank you so much for your brilliant exploration !!!!
I have to know this crap for my Introduction to Psychology uni course. I’m only a freshman undergrad & I’m just so confused lol. This is very advanced biology material... I hope I’ll get the gist of it soon.
Pray for me and my fellow confused psych peers 😭
Same. This video is very advanced though. There are less detailed videos for our level by the dozens. Good luck!!
the key to knowledge is curiosity
If you make more videos then it would be a light for us.
Thank you for the video
I dont usually comment on videos but you did a good job, thank you
Hey, very informative video. Gave a clear understanding. I wish the transcripts of the video was given in the video description.
i finallllly get this now. I’ve been frying my brain for 2 weeks
Thanks so much, it helped me so much, even though it was in english. So much better than how our prof tried to explain it to us, I didn't understand a word back then :D
Wow, the best explanation ever for this subject is yours👏 👌
Sarah the way you explained this slide was amazing,
very easy to follow along and you made it much easier to understand. you should keep going with those videos,
Especially since 70k views mean that most of us don't really understand this topic and might actually do well on our exams thanks to you! :)
the best video I found on the topic, great job!
This is the best explanation THANK YOU!
thankyou for this video, really helped clear my concept about off and on center bipolar cells
You are really good at describes than our professor !
Thanks for this! What happens in figure c? Why is the output so strong if most of the periphery is covered?
Awesome presentation with great slides
Damn!! This was sooo good. Thank youuuu
awesome video!
Thanks - nice explanation!
really good explained. There is no video in german that explains the topic of receptive fields.
one of the most complicated things to understand
love love love this sm sm
شكرًا جدًا! Thank you from all my heart
On center is having mGluR which is activated by low conc. Glutamate where as surrounding zone is having ionic GluR which is sensitive to high conc glutamate ....Less glutamate activates mGluR so more depol. at BPC as well as GC in on-center off-surroundings where as in opposite case when center is dark, more glutamate releases due to Hyperpol. and it acts on Ionic GluR so depolarisation occurs at BPC, GC....leading to Off center on surrounding situation..😊
OMG THANK YOU FOR THIS!!!
Thanks. Extremely well explained !
Thank you for saving my grade!!
Thanks,honestly
Thank you sooooooo much. This is a life saver
this video helped me so much! Thank you!!!
Thank you for this!
Great explanation. Thank you
I finally get it! Thank you! 😭❤️
What a wonderful explanation. Thank you so much. One question though, what's the clinical significance of knowing all of this?
This helps us understand how vision is generated and how we are able to interpret contrast between dark/light and various colors.
Thank so much very informative for report in my physiological optic class
Thanks a lot for your explanation! I also have a question, just to be completely sure:
Can we say that we have ON-center-OFF-surround and OFF-center-ON-surround receptive fields in both bipolar cells AND retinal ganglion cells? :)
The best video, thank you!
Hi, great job! Can you explain why the firing rate is higher in illustration c than a? when both the center and the surround are in the dark
It's because the effects of the off-center bipolar cell are greater than those of the surrounding bipolar cells.
It’s due to the amacrine cells that act to (partially) inhibit the central retinal ganglion cells. It’s not a strong enough stimulus from these amacrine cells to completely negate the output, however it reduces the firing rate of these neurones.
Thank you for this video! I was able to understand the terms much better
Thank you 😢❤
Great explanation 💙
Loved it ! Thank you
that was very helpful, thank u
Amazing!!!
Thank you! Excellent video
I have a question and i have searched all internet for this haha. But the space above and bellow spontaneous activity is Asymmetrical. So when switching light off the spontaneous activity van only drop so much before it reaches 0. This is a problem (i don't really understand why)? And that's one of the reasons why the cells have an on and off center, because of the asymmetry. But i don't really get how the on and off center help with this
So if light is present on center ganglion fire if light absent off center ganglion fire so both are firing how it make sense
Amazing
horizontal cells relase GABA and not Gly, don't they?
yea
depends, as an opthamologist myself i can tell you there are different types of horizontal cells that secrete different nt, but the effect is inhibition, there are 30 or so amacrine cell types and at least 3 ganglion cell types in humans
thanks Sarah.
this helped a lot :)
Thank you so much.👍 Wonderful explanation. From which book you got those diagrams?
Can the same explanation be used for opponent theory of colour vision?
Very well explained ... Thnxx
Keep going!!
Thank you ❤
nice explain
Thank you! Any book recommendation ??
I thought Horizontal cells release GABA?
Yeah and gabais is inhibitory, so it checks
what is the bipolar cell's ionotropic receptor called?
Hi!
Could you please explain the cell output at the end of the video?
These are the total action potentials vs time?
Thank you!
Nicolas Mbolamena yes, these represent relative counts of action potentials (so figure a has relatively fewer action potentials relative to figure b)
Why do we have ON AND OFF BC, instead of having just 1 type of BC ?
Hi Sarah, first thanks a lot for making this great vid
I have couple of question:
1. how are those rf connected to the different types of cells(simple complex and hypercomplex cells) is it that several of those rf connected to same cell in the visual cortex?
2. how are the different types of rf formed? as i understood we have 4 types yellow on-blue off, blue on-yellow off, red on-green off and green on-red off? if we only have red blue green cones?
thanks again :)
Yellow is a combination of Red and Green! (counter-intuitive, I know!) Receptive fields are formed by neighboring fields of red surrounding green, red and green around yellow, etc.
Several receptive fields do map on to single cells in the visual cortex!
You saved me !!
Awesomeee
This is above the scope of psych 100 right? I don't know if I'm going to fail my test or trying to learn something too advanced for my class. Is this necessary for the perception and sensation chapter of first year psychology
Nah. You don’t need it for 100’s psych, I would guess. All I knew for that class about photoreceptors was cones=color perception, rods=brightness perception. Hope you didn’t fail though
Could you explain why light hyperpolarizes the photoreceptors? Thanks!
The default state of photoreceptors is depolarized in the dark (aka dark current). When light hits the photoreceptors it shifts the conformation of rhodopsin, leading to activation of a G protein pathway that degrades cGMP. cGMP is what keeps sodium ion channels open in the photoreceptors, so when you have less cGMP, the channels close and the cell hyperpolarizes.
Does this mechanism relate to the trichromatic or opponent-process theory?
I would say that this mechanism is more relevant to understanding the underpinning of the opponent-process theory.
My textbook call them ON/OFF ganglion cells?
omgg thank youuuuuu
I have poor resolution. I can barely diagnose things what could it be?
Could you please make a video explaining what that "patch of retina" in the upper left corner "is"? Are ganglion cells really microscopic little circles surrounded by a bigger circle which in turn is surrounded by a patch or retina? I thought that these "circles" were mere abstract representations of the visual field (in a sort of topographic map), as I learned from this video:
ruclips.net/video/oBJSG15Nq2E/видео.html
😢 all stm on off😮 total saince 😮lala real 😮😮
Sorry to say but you're too fast
Wrong explanation!