The horizontal cell are between the rods and the bipolar cells and they work using GABA in responds to Glutamate (more glut=more GABA=more inhibition)

Best visual explanation of this phenomenon that I have found. Cleared up a lot of questions for me. Thanks!

@CKLH I'm sorry, for some reason I just realized that I hadn't responded to your comment. Actually, I'm not really sure what that statement means. I tried to find an answer but couldn't. Hope you find it!

Horizontal cells are not directly connected to Ganglion cells

@thesameidiot All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions. All the best

@PittDr All questions are answered in the Interactive Biology community forums from now on. Go to the website in the description and then visit the community. This is to make it as efficient as possible as we have multiple people over there to help answer questions. All the best

@LeeSuzanna Thanks for your feedback. I'm glad that you are finding value in the videos. I'm actually a High School Science and Math Teacher. If you check out my website, you can go to the About Page to find out more about my background. My site is listed on my channel page.

@jaxn You are very much welcome. Thank YOU for your encouraging comment :)

@beinwhitebites Sorry, but not at the moment. Working on other videos. I've moved on from the nervous system for now.

I just watched all 5 eye videos. AMAZING. it made everything so much easier to understand from class. thank you

@marstricker You are very much welcome. Glad you found it useful. Stay tuned for more :)

@sanyafolkesson That's awesome to know. Glad you are finding the videos helpful.

shouldn't the modulation cells be the amacrine cells not horizontal?

This was very helpful. Videos 32-35 summed up a 3.5 hour medical school lecture in 30 mins. Thank-you soooo much!!!

it really helps to understand the processes that happen in the retina! Thank you very much!

@sharpiemarker99213 Glad you are enjoying them. Stay tuned for many more!

In Animal Physiology now and I was so lost. This doesn't go into as much detail as our textbook (probably because you made this years ago) but it's a start! Thank you! :)

Hey ...I think that in field surround the sequence must be Receptors...horizontal cell...bipolar cell ...ganglion cell

@molekularacNS I'm not 100% sure about that because I'm not sure what the neurotransmitter is that is released. Might have to look into that. Glad you are watching so many of the videos. Many more are coming :)

All the videos on vision are really clear and helpful! Thank you so much =D

@TheYazzola Thanks for your input!

@jennyuzzy YOU Rock! And you're very much welcome!

@TouchMyAwesomeButton Glad to hear. All the best!

@07gea That is correct. On pathway describes the on response (whether center or surround) and the off pathway describes the off response.

@aykhk7 I don't remember the textbook. It's from notes I took in college. If your book says something different, go with it. My videos (like many textbooks), can have errors in it. Do your research and you'll find the answer :)

@TheOptimisticOctopus you are very much welcome!

@XxXxSteffXxXx That's a very good question. I'm guessing that it would depend on how strongly each is stimulated. Although, I haven't looked specifically at that so I can't tell you for certain.

Awesome video! It's just what I needed, and it clearly lines up with what is stated in my Costanzo BRS Physiology book, 3rd edition. Thanks for the visual explanation! :D

@Blue2013KITE It means that when it's stimulated in the center, it gets the OFF response (hyperpolarization and then post inhibitory rebound). When it's stimulated in the surround, it gets the On response (depolarization and burst of nerve impulses). It's the exact opposite of what is shown in the video. Hope that helps.

@tashapi01 Yes, it can be confusing. The fact is that the Nervous System is VERY complex. That's just a different type of ganglion cell that responds in the exact opposite way of the On Center, Of surround cells. In response to light in the center, there's the inhibition and post-inhibitory rebound. In response to light in the surround, it gives a burst of nerve impulses. The brain then combines all the different combination and forms the image you see. Hope that helps!

Thank you for this informative video as it clears up much of the confusion

@molekularacNS The horizontal cells basically inhibit the ganglion cells when they are stimulated. They do this by using an inhibitory neurotransmitter. That neurotransmitter binds to receptors on the ganglion cells that causes the ganglion cells to become hyperpolarized.

This makes so much sense now! Thank you!

Nicely done video, I learn about stuff like this to get ideas for experimental circuit designs. I found this valuable, thanks!!

I watched my lecturer's response like 100 times, didn't understand anything and left even more confused. I watch this video once, and I understand it so much better. Bless you

Neuroscience-exploring the brain by Connors and Paradiso shows that the order is: For the center: Rod - bipolar - Ganglion For the surround: Rod - horizontal cell - bipolar - Ganglion

This was very helpful, thank you. The way you speak slowly and use repetition really helps drum it in :-)

@nashgalira Yes, it is related to lateral inhibition. I talk about it in Episode 34. Check it out.

My professor tried to explain this in class but I found this explanation with images very easy to understand. Thank you.

@shawnchong89 Very much welcome! Leslis is from St. Maarten :)

@xxcpxx That's awesome. Glad it helped you to understand and hope you get an A in Neuro :). Make sure to spread the word to your classmates :)

Thank you!! My psych text sucks and takes all the detail away for understanding the mechanism. You filled all the voids with your video!! THANNNNNNNK YOOOOOOOOOOOU!!!!

Hey! I really like your videos and they are really helpful for studying, but i have to say that there are sometimes mistakes in them. In this video you say, that the ganglion cell and the bipolar cells of the surround-area of the RGCs periphery field are connected via horizontal cells. Actually it's the Amacrine cells that form that connection, horizontal cells connect neighbouring photoreceptor cells. But that leads to the same center-surround effect you are describing, caused by lateral inhibition, it is only the image which is not correct

@jock10171017 The truth is that it's even more complicated than you describe. There are always details that can be left out. The human body is much more complicated than what I'm showing in this video and what you are saying in your comment, and more complicated than we fully understand it to be. This video is a general overview, and does illustrate some of the major processes that happen.

excellent videos! very clear and easy to understand

I applaud your efforts to explain this fascinating topic, but as has been pointed out more concisely by others, this is unfortunately a little confused (and wrong), Horizontal cells perform lateral inhibition in the outer synaptic layer - i.e. they are post-synaptic and pre-synaptic to rods (in your example) and pre-synaptic to the relevant bipolar cells (as well as being connected to each other via gap junctions). If anything, the position at which you show horizontal cells to be in your video (within the inner synaptic layer) should actually be taken by Amacrine cells. But the extent to which Amacrine cells are involved in feedback mechanisms is not (as far as I have learned to date) fully understood. I believe that there is very current research into whether starburst Amacrine cells might be involved in retinal processing for motion detection. I can see how the key idea of general lateral inhibition can still be drawn out as you present it, but the relative positions of horizontal and amacrine cells is crucially important.

You literally save my life

you're a genius thank you!! much more easier to understand than the 1 hour lecture my prof gave

thank you so much! you have been a great help for my assignment!!!

@greencarrots08 They do cause inhibition yes, and then you get the post-inhibitory rebound.

These are excellent by the way - keep it up!

No questions, but thank you so much. This is amazing/life-saving. You're doing God's work!!

Great explanation .... !!! thanks, you've helped me a lot

oes the input form the center receptive field go through horizontal cells when it is off-center on-surround?

@InteractiveBiology I've heard that horizontal cells inhibit glutamate release from neighboring photoreceptors as well. Which book did you use as your source?

thanks for the clear video! are the horizontal cells not connected do the bipolar cells?

AMAZING. I've been sitting here, trying to figure out this concept and it just hasn't been working. Great video!! You might just help me save my grade in neuro :)

Awesome explanation, thank you very much!

I thought amacrine cells connected bipolar and ganglion cells

Thanks for the videos. It would also be interesting to make an episode on "Saccadic" searching way of human vision.

REALLY helpful thank you

i am currently reading a textbook that refers to on center, off surround ganglion cells as 'off center and on center' is this correct?

We do actually understand a lot of how the body works in broad detail. Horizontal cells do not connect to ganglion cells. They connect to on or off bipolar cells which then synapse with ganglion cells. The activity of the bipolar cells results from input into their receptive field (composed of direct input from photoreceptors and indirect input from horizontal cells) and then goes to ganglion cells both directly, and also indirectly via amacrine cells.

And you are right, text books do have mistakes at times, but in this case i haven't seen a difference with most of the major text. All the same what determines knowing the actual orientation of the cells is histology and electron M. So we must research.

Does the PIR (post-inhibitory rebound) explains why surround illumination followed by dimming leads to highly frequent action potentials?

very well done! Thank you, and god bless you

does the input form the center receptive field go through horizontal cells when it is off-center on-surround?

inhibition accentuates borders in the visual field. It's why you easily can follow borders of a white piece of paper lying on a white table. The nervous system likes to accentuate borders/changes so that we notice even fine change. The focus is on change itself. Compare w temp. When you sit in the hot tub, u almost feel pain as you get in. The body reacts sharply to the change of temperature. After a while the sensory system adapts and you relax. Changes seems to interest the sensory syst most.

Question: So this is the direct cause for the slightly over contrasted boarder we see between two different colours (or brightnesses/energy potentials, meaning something in contrast to each other), right?awesome videos your creating by the way :D

Horizontal Cells synapse with photoreceptors in the External Plexiform Membrane. So Ph--H--Ph. Amacrine synapses with Ganglion Cells in the Internal Plexiform Membrane. so it's G--A--G.

Its really nice how you try to explain these potentially confusing detail, I commend that, however just 1 thing the issue about the horizontal cells, leading physiology texts such as Ganong, Gyton and Berne and Levy all says that they connect the rods and cones, bipolar and even interplexiform cells not the ganlion cell directly, the amacrine cells however do connect them as well as bipolar. what i suggest you can do is, put a pop up text saying the difference if you see other books differ.

But r the receptive fields fixed areas or is the point of maximum light intensity always the center and the surrounding parts the periphery?

does that mean glutamate released by centre receptor is inhibitory and that of surround is excitatory ?

You are awesome. Thank you.

This video lines up with pics on MIT, McGill, and Harvard's websites. It also matches the pics in Gazzaniga's psych science text (2009).

@InteractiveBiology the neurotransmitter released pretty much throughout the visual system is glutamate.

This video kind of misses a bit of the information flow... Mohammed seems to have summed it up more accurately - Receptors -> Horizontal (with feedback inhibition of receptor output) -> Bipolar -> Amacrine (with feedback inhibition of bipolar output) -> Ganglion

is one ganglioncel always connected with multiple rods or can one ganglioncel also be connected with only one rod ?

Does a ganglion cell generate one 1-d receptive field or 2-d?

amazing .....great

How do complex and simple cortical cells fit into this model?

good lesson. Help a lot!

Amacrine cells not horizontal cells, no?

@InteractiveBiology The structure of the Retinal cells are well-known and there shouldn't be any disparities between most authors. More reading and you'll find consistencies in what @virregribbe mentioned. H do not connect to G at all. B are the only link between Rods/Cones to the G. H are lateral processing neurons that connects between Rods/Cones. There is something called the Amacrine Cells that behaves just like H. You might want to redraw the diagram.

Can someone explain what this has to do with mGluR and Kainate receptors????

Pretty sure that Horizontal cells don't contact the ganglion, H cells synapse onto cones from cones

The Pathway is Photoreceptor - Bipolar Cell - Ganglion Cell. The different effects of ON-center or OFF-center bipolar cells or ganglion cells is due to the receptors expressed on the bipolar cells. Horizontal cells (and amacrine cells to some extent) are involved in LATERAL INHIBITION. This process is used by the retina cells in order to accentuate contrast, i e, borders of between light and dark objects in or visual field. I guess it's why we can see a white paper on a white table with ease.

@InteractiveBiology stimulation of both the center and surround produces only a mild response (due to mutual inhibition of center and surround)

how I can I describe the different ganglia cells in different parts of the visual processing? I know they are at the eye level and in the cortex level. Can you please describe its function and importance please?

THANK YOU THANK YOU THANK YOU! you are awesome.

System is designed to react (max output) when there is a difference between the center and surround, for example when the center is stimulated by light, but not the surround or vice versa. The fields OVERLAP EXTENSIVELY. The greatness of it all is: 1) Contrast is accentuated 2) The cells are, on a low level, always active. From a low level, it is hard to code a decrease in light with lower levels. With both ON- and OFF-centers, that overlap. CHANGES are always coded with increase in firing.

...this leads to a lower influx of Ca2+ and lower release of Glutamate. reaction (important part): on-bipolarcell > lower efflux of K+ and that leads to a depolarisation off-bipolarcell > lower influx of Na+ and that leads to a hyperpolarisation so in your example the center is build by on-bipolarcell and the surrounding by off-bipolarcells.

From Adler's Physiology of the Eye chapter 21 "direct current injection into non-mammalian HCs clearly shows an effective, low-frequency dominated, sustained path from HCs to GCs." BOTH horizonatal and amacrine cells seem to be involved, and as stated in the video horizontal cells seem to connect to ganglion cells

please I have a question : is it possible for a ganglion cell to be on centre/off surround in some cases and off centre/on surround in other cases ? ?

great video

@virregribbe Sorry to break it to you, but it's so complex that I've seen different descriptions in different books, so I picked one. Yeah, I know - It's crazy. We don't fully understand all aspects of this complex thing we call the human body. Makes you wonder . . .

Is "on center of surround ganglion cell "also referred as "excitatory center inhibitory surrounds"?

can you do some videos about learning and memory?

actually wikipedia is quite reliable when it comes down to it. The problem with accuracy is not due to the information being on a screen or on a piece of paper.

Very helpful! My lecturer did not explain this properly!!!