Visual Pathway Lecture Notes

I&#39;m in Aries in this video we&#39;re going to talk about specifically the visual pathway so we&#39;re going to take how the light hits the retina and we&#39;re going to take it through the optic nerve and all the other different process if you guys have already watched our video on the phototransduction cascade that&#39;s going to be very very important that you do that before we get into this visual pathway because we already talked about exactly how those light rates got converted into chemical changes and then electrical changes and how they went down the axon to the ganglion cells which basically made up the optic nerve all right so now we&#39;re going to have two eyeballs right this is the we&#39;re going to say this the left eyeball and this is the right eyeball okay now first things first what I want us to try to imagine if we&#39;re gonna put a lot of different concepts together when you guys are looking you guys are like looking at anything around you we our eyes are so amazing that they can pick up different types of visual fields so for example this is the right visual field or the right visual field and this is the left eyes visual field okay so what is this one right here this is the right eyes visual field and this one over here is the left eyes visual field okay now with in the visual field you have two different components of this visual field we&#39;re going to say this is the nasal so since your you&#39;d have your honker right there pretend this is your nose okay so pretend this structure here is your nose okay since this is the nose these two structures that are near the nasal region this is the nasal component of the visual field alright so this is the nasal component of the visual field and then this one over here would be near the temple so this is the temporal component of the visual field and this over here is going to be the temporal component of the visual field okay now to make it easy though now that we know that this is what it is it&#39;s nasal and the temporals these words are going to get interchanged a lot so I do not want to confuse you guys so what I&#39;m going to do is for the sake of it is I&#39;m going to switch nasal and since this is the right visual field this is what gets confusing the right visual field has a left visual field and a right visual field okay so the right eye has a left visual field and a right visual field so we&#39;re going to say this is the left visual field and this is the right visual field okay so I just want to make it as simple as I possibly can here this whole right eye is going to have two fields it&#39;s going to have the right visual field and last visual field same thing this left eye is going to have two visual fields it&#39;s going to have a left visual field and a right visual field okay simple as that now we&#39;re going to be able to kind of do this a lot easier now so instead of using the words nasal and tempore but understand those words because it&#39;s going to be important lesions okay let&#39;s say first off when we&#39;re looking out let&#39;s say that this part of the retina there&#39;s two parts of the retina so this is the right eye this part of the retina is closest to the temple or the right temple right so we&#39;re going to call this part of the retina we&#39;re going to call this the temporal Hemi retina okay that&#39;s a temporal Hemi retina now here&#39;s what gets really funky the temporal Hemi retina is receiving light rays from the left visual field okay so from here this part here this left visual field is hitting this part of the retina okay so if light rays from the left visual field are hitting this part of the hit retina that temporal heavy right now but then the what is this one this one is close to the actual nose so since it&#39;s close to the nose this is called the nasal right Hemi retina so it&#39;s called the nasal hemorrhage now and it&#39;s called the temporal Hemi retina the nasal hemorrhage now is receiving light from the right visual field so the nasal Henry retina is getting hit with light from the right visual field all right so just to make sure we&#39;re clear left visual field hits the temporal hit me right now and the right visual field hits the nasal heavy retina sweet deal same thing would happen up here what would this one be this one right here would be the temporal Hemi retina want to put a char here and this right up here is going to be the nasal Hemi retina okay and same thing nasal heavy rain is going to be receiving visual field from left visual field so it&#39;s going to be getting it from the left visual field and then the temporal Hemi retina on the left eyeball is going to be receiving it from the right visual field okay now that we&#39;re done with that what happens with these fibers here&#39;s what I want you to remember anything from the right goes to the left anything with the left goes to the right that&#39;s it anything that&#39;s coming from the left okay well this temporal Hemi retina this is on the right eyeball okay so this is the right eyeball it&#39;s picking up information from the left visual field well anything from the left has to go to the right oh so these should stay on the same side then so these fibers right here they should not go and cross over to the other side they should stay on this same side so they&#39;re going to come down the optic nerve and you know what happens the two optic nerves actually come together they come together and form this big old structure that you kind of see right here I&#39;m actually not going to do it in brown here because I&#39;m going to use this brown a lot I&#39;m just going to say here at this point here where the two optic nerves are connected all of this part right here this whole thing is called the optic chiasma and the optic chiasma is where the right optic nerve and the left optic nerve come together right near the pituitary gland so this is right here the pituitary gland okay now what happens here the fibers from the temporal Hemi retina which is receiving it from the left visual field we said anything from the left visual field will go to the right eye okay so this is going to cross means lock of the cross it&#39;s going to stay on the same side so is going to come down the right optic nerve where the optic chiasma is it&#39;s not going to cross it&#39;s going to stand the same side and it&#39;s going to move down this structure right here which is called the optic tract and we&#39;re going to stop right there okay so what is this structure right here this long tube-like structure here this whole tube like structure here is called the optic tract so this would be the right optic tract what do you think this one is this is the left optic tract and this is the optic chiasma okay now let&#39;s follow this nasal hemorrhage huh well the nasal henry retina is receiving information from the right visual field well anything from the right goes to the left so this is got a cross so these fibers from the nasal Heming retina it&#39;s going to come through the optic nerve the right optic nerve and it&#39;s going to cross at the optic chiasma and go over here to the opposite side it&#39;s going to come over to what optic tract it&#39;s going to come over here to the left optic tract and it&#39;s going to come right to there and that&#39;s what we&#39;ll stop at that point okay now we understand this this should be a lot easier now let&#39;s do this one nasal hit me right now it&#39;s receiving what it&#39;s getting hit from the last visual field well if it&#39;s receiving information for the left visual field anything from the left has to go to the right okay well this is on the left that means it has to cross over here so it&#39;ll come down the left optic nerve but then instead of going on the same side it&#39;s going to cross over it&#39;s going to become contralateral right and these fibers are going to come over here and they&#39;re going to move all the way over here on this side and come right there okay so all the things that are coming from the left visual field on the left nasal Hemi ratney is going to be coming from the left visual field it&#39;s going to be taking that information on the right optic tract and into this area that we&#39;re going to talk about in a second let&#39;s keep going temporal Hemi retina it&#39;s going to be receiving information from the right visual field right of the left eye so it&#39;s going to be receiving from the right visual field one new thing from the right goes to the left where are they on the left side of the eye let&#39;s just keep it up see lateral so these fibers here are going to come down the left optic nerve it&#39;s not going to cross at the optic chiasm it&#39;s going to stay on the same side and move down the left optic tract and then to this area right here okay so these are your fibers that are crossing and these are the ipsilateral fibers so what do these fibers right here called these fiber gears that are staying on the same side are your itsy lateral fibers these are the ipsilateral fibers and these fibers here that are crossing are called your contralateral fibers contra lateral fibers okay all right sweet deal now that we know that let&#39;s keep it bring or keep bringing it to where we&#39;re going to go next so we already went from these hmmm your retinues from the visual fields we followed it down their optic nerves the optic chiasm we folder down the optic tract we see the FC lateral fibers and we know the contralateral fibers sweet deal what happens is from this optic tract it&#39;s going to come to a special area in the thalamus I&#39;m actually zooming in on the specific nucleus on that ballast but let&#39;s say pretend here that I have I draw kind of like a little view of the thalamus it has kind of like this like piece like symbol a little bit and it kind of looks like this and what happens is it has a special nucleus coming off of it right it has a special nucleus coming off of it like this it&#39;s called the lateral geniculate nucleus what I&#39;m doing is I&#39;m taking the lateral geniculate nucleus and just zooming it on it okay so this right here is the thalamus but a special nucleus of the thalamus is called the lateral geniculate nucleus I&#39;m taking a large Nikolov nucleus and zooming in on it okay so that we&#39;re clear so this is lateral geniculate nucleus it has a total of six layers six layers so let&#39;s layer this one two three four five six and the same thing over here one two three four five six why am I telling you this because any epsy lateral fibers go to two three and five layers so FC lateral fibers within the lateral geniculate nucleus are going to go to layers two layers three and layers five so what does that leave for the contralateral the contralateral is left with going to one four and six so then the contralateral fibers will go to one four and six okay so now it comes in to this area right so I&#39;m going to kind of make these different because obviously the same color but look here from this one this is the contralateral so this one is the contralateral fiber the contralateral fiber goes to what one four and six so if I were to do it let&#39;s actually just make it a different color from this point so that we&#39;re not confusing this so now I&#39;m going to come from this contralateral fiber it&#39;s going to be maroon it&#39;s going to give connections to what for it&#39;s going to give connections to six and it&#39;s going to give connections to one then the ipsilateral fibers are going to go to two three and five okay and the same thing is going to happen over here let&#39;s say that I just for the sake of it I do the same thing over here at the FC lateral fibers and the contralateral fibers over here so this one here is the contralateral I&#39;m going to keep the contralateral maroon contralateral goes to what it goes to six it goes to four and it goes to one if see lateral fibers are going to go to two three and five now from this they&#39;re going to come out of lateral geniculate nucleus so these fibers are going to be coming out of the lateral geniculate nucleus so the terminate in this area some of the fibers we&#39;ll talk about when we talk about the pupillary light reflex some of these fibers can actually go from the lateral geniculate nucleus and into the specific area of the midbrain there go into the midbrain and there&#39;s two structures in the midbrain that&#39;s a very important one is going to be right here called the superior colliculus it&#39;s going to give off some branches that can go there so some of the fibers can go here to the superior colliculus so some of the fibers can come to the superior colliculus but a really really important one is going to be just anterior to the superior colliculus there&#39;s a very important nucleus here called the pre tectal nucleus so really important nucleus here called the pre tectal nucleus and we&#39;ll talk about this one how it&#39;s connected with your basically the constriction of the pupil okay so that&#39;s the protective nuclei we&#39;re not gonna talk about that now we&#39;re going to talk about the rest of this pathway okay I suppose you realize that some of these fibers can go into the midbrain however most of the fibers are going to continue let&#39;s do this in pink now let&#39;s bring it all nice and nice and pretty alright so coming out of the lateral geniculate nucleus there&#39;s going to be two types of fibers one is going to run through the temporal lobe and come to this area of the occipital lobe so you see this right here all this structure that we have right here this is representing the occipital lobe so this is the occipital lobe and this would technically be on the left side and this is the occipital lobe and this would be on the right side and what&#39;s it separating them is what&#39;s called the calcarine fissure right so it&#39;s called the calcarine fissure right here I&#39;m not going to do that I was remember it&#39;s the calcarine fissure all right now some of the fibers from ladder&#39;s nickel a nucleus move through what&#39;s called the temporal lobe so some of them move through an area of the brain called the temporal lobe to go to the occipital lobe some of the fibers actually move through the parietal lobe to come to the occipital lobe so what&#39;s the other one right here this would be the parietal lobe and then the same thing would happen over here so if we just continuously do this because it&#39;s going to be important that we make this very very consistent here one&#39;s going to remove through the temporal lobe to come to the occipital lobe and one&#39;s going to move through the parietal lobe to come to the occipital lobe okay sweet stinking deal this is the temporal and this one right here would be the trial the reason why I&#39;m being so picky is because these ones have different they&#39;re different types of fibers these are actually the ones that are moving to the parietal lobe these are called the superior retinal fibers they also call it baram&#39;s loop so some bærum do musta came up with it right so these superior retinal fibers are actually also called barrels and they&#39;re moving to the parietal lobe these ones that are moving to this temporal lobe are the inferior retinal fibers so these are the inferior retinal fibers and this is actually called meyers loop so again some some dude named meyers came up with that right so again inferior retinal fibers and this is a part of meyers loop and it&#39;s important because it talks about and when we get to lesions right okay now these are moving to deprive the lobe they&#39;ll come to the occipital lobe and they&#39;ll go to a specific area specific like part of the occipital lobe and that specific area of the occipital lobe is actually called the striate cortex and the striate cortex is basically the primary visual cortex so the striate cortex is basically the primary visual cortex this is where the perception of these visual stimuli become what we see okay so how we perceive these different types of images okay so that&#39;s an important thing to know these fibers are coming to the striate cortex of the occipital lobe which is the primary visual cortex where their perception of these visual sensations are actually occurring all right now that we&#39;ve done that I need us to apply some visual like correlations that there are certain types of lesions and different fibers here okay now the only reason I&#39;m saying that is to know this is great but why do we need to notice because we need to apply it to clinical settings so let&#39;s say here that I have a couple different lesions I&#39;m going to make it as simple as simple as possible let&#39;s keep all the colors here let&#39;s do it in like this maybe we&#39;ll do in purple here will represent the lesion by purple I&#39;ll say there&#39;s a lesion here so that&#39;s leaves you&#39;re number one okay then let&#39;s say that there&#39;s a lesion right here so there&#39;s a lesion right here this is leisure number two then let&#39;s say that there&#39;s actually going to be a lesion on the outside here and outside here at the same time so let&#39;s say that this is lesion number three then let&#39;s say that we have a lesion that&#39;s occurring right here leisure number four and then we&#39;ll have a lesion here like lesion number five lesion six and then what happens if we had damaged the whole thing lesion seven and the last thing is what if we develop some type of damage to the occipital lobe and that will be lesion eight so eight total lesions is what we&#39;re going to talk about here okay here we go if the right optic nerve is damaged let&#39;s do our visual fields here let&#39;s get our little visual fields here keep it super super simple here here&#39;s our visual field for the right eye so we&#39;re gonna have two visual fields here one right there for the right eye one right there for the left eye and we&#39;ll separate into the left visual field and right visual fields so again this is for the left eye this is for the right eye if this right here is damaged this right here is damaged this optic nerve then I&#39;m losing what I&#39;m losing the certain types of visual sensations from the right visual field of the right eye okay so right visual field of the right eye it&#39;s gone I have no vision in this area so let&#39;s go ahead and shade that in this whole thing go on I got no vision there I developed some scotoma right there I lose all my vision in that that visual field then any of the information all the visual sensations that are coming from the left visual field of the right eye that&#39;s gone - alright see ya see you later that&#39;s it I lose all the information from these two visual fields of the right eye what do I develop I develop mono ocular blindness which side right sided mono ocular blindness so what is this called right here mono ocular blindness or an obeah so we can say that this is right side mono ocular blindness or an opium okay simple of that and this would be lesion number one so Louise you&#39;re number one if you damage the optic nerve you&#39;re going to have complete right side of the eye mono ocular blindness no vision there second one let&#39;s say that you develop a pituitary tumor and it compresses the medial part here of the optic chiasma it&#39;s compressing the contralateral fibers here so let me make two visual fields here okay so this one is going to be again this is for your left eye and this is for your right eye well it&#39;s going to be affected here if I damage the contralateral fibers what does that mean okay let&#39;s follow this one over your nasal Hemi ratney I&#39;m losing the visual sensations from the left visual field of the left eye that&#39;s gone see you later they&#39;re like hey let&#39;s do this in a different color here like this this is gone okay so I lose that sight I lose my temporal visual field or the left visual field of that left eye right then what I&#39;m also damaging these fibers and if I damage these fibers this is picking up information from the right visual field of the right eye so now this is gone so I&#39;m losing my temporal vision on the right eye because I&#39;m losing my vision and both the visual fields two temporal fields right the temporal fields this is called they got a heck of a name for this one they call it by temporal Hemi a no Pia or enough and they not hemianopsia you can even say like that so bitemporal hemianopia okay that&#39;s done what about three okay let&#39;s say that there&#39;s some type of you know the internal carotid arteries kind of run nearby here so there&#39;s actually internal carotid arteries that runs very very near this optic chiasma right here let&#39;s say that for some reason these guys develop like an aneurysm right and they compress these outer parts here be careful you have an aneurysm of both of them and it&#39;s actually compressing both these fibers what fibers the ipsilateral fibers so now let&#39;s draw your two visual fields here this is four three okay this is your left eye this is your right eye okay if it&#39;s damaging the ipsilateral fibers you&#39;re going to lose information from the nasal field of the left eye and if you&#39;re damaging this FC lateral fiber you&#39;re going to lose the nasal field of the right eye well that&#39;s by temporal this is going to be by nasal by nasal hemianopia will turn me over and tickle me twisted look at that that&#39;s called by nasal Hemi a Nokia or in nobs synopses right so by nasal hemianopia is the third type of lesion so I&#39;d be number three so this is number three here this was number two and this was number one okay now off the number four if you lose number four let&#39;s make our visual fields here and I&#39;ll do it like this again left eye and right eye left and right visual fields bye damage these bad boys all this right optic tract let&#39;s follow it the right optic tract let&#39;s follow this one first okay come over here come over here come over here okay Mazal heavy right knees not going to work so I&#39;m gonna loop my would lose the left visual field of my left eye so last visual field of the left eye gone that&#39;s gone okay follow this one if we follow this one follow this one for this one we go over to the temporal Hemi retina which I&#39;m losing it from the nasal side of my right eye that socks and if I loose it from the nasal side of my right eye what would I call this one they got a heck of a name for this one all right it&#39;s a little tight it&#39;s a tiny bit confusing but I want you guys to remember remember we said that this was the temporal and the nasal nasal temporal right we also said that we could say that this is the left visual field in the right visual field and left eye left visual field of the right eye and right visual field of the right eye what did I lose I lose both of my left visual fields of both eyes so because of that they call it left homo nyam is Hemi and Opia why not so that is the fourth type of lesion and you would have the same thing at that hashing on the left optic tract except to be right homonymous hemianopia so again this is lesion number four it&#39;s called left homonymous hemianopia now let&#39;s say that we get back here we get back here now these are the these are the frackers these are the one that can be a little bit confusing here let&#39;s say that I do number five here right so now I damage this part the actual what loop the baram&#39;s loop which is called the superior retinal fibers before I move on let me make a mini little diagram here so that I can really really make sense of this we can split the visual fields up like we did over there but we can actually if we really want to be very very specific let&#39;s say I make here this is my left visual field my right eye left eye sorry left eye right eye remember how we split it into a left visual field and a right visual field for both of them guess what we can split it into a upper left upper right lower left lower right okay now let&#39;s say everything up above this part that I have in blue this is all the superior part right so this is the superior part of the retina all this down below is the in fear red now when we&#39;re talking about the superior etta no fibers okay now I&#39;m looking at the eye like from my eyes like imagine here I have my eyeball like this I&#39;m actually fixing my eye and looking straight down like this into the eyeball okay let&#39;s pretend for a second though that I look at it like this now I take this eyeball here and let&#39;s say up here I have my superior part of the retina and then down here I have the inferior part of the retina the superior part of the retina is getting hit with light rains that&#39;s coming from the lower visual fields and then the inferior retina is getting hit with light range that&#39;s coming from the superior visual field it&#39;s frickin crazy I know but I&#39;m sorry that&#39;s how it works so now when we make this one we have to make it like this here&#39;s left eye right eye we have to split it like this but then into fours okay superior quadrant in your quadrant okay okay now let&#39;s let&#39;s think about this if this suit we damaged this right side the right superior retinal fibers if the right superior retinal fibers are damaged remember anything from the right side is coming from the left eye or the left visual field so again anything that&#39;s coming from this is coming from the left visual field anything that&#39;s on the right eye is coming from the left visual fields so want to make sure that we get that completely clear if this is damaged the superior edge no fibers then I&#39;m losing the vision within the inferior visual field on the left side okay so we already know that I&#39;m losing the actual left visual field that&#39;s already clear does anything from the right eye is picking up information from the left visual fields so all of this is gone the left side but remember superior at no fibers only pick up the information from the inferior visual field so really we&#39;re only losing this part here and we&#39;re only losing this part here so because I&#39;m losing vision within the lower quadrant of the left visual field we call this what this one&#39;s a heck of 1 to left inferior quadrant Hemi and Opia okay so left inferior quadrant hemianopia and it&#39;s because we&#39;re losing our vision within the left visual field and in the inferior plane okay then if we did a lesion here in the sixth one right so we said that we damage this six one here so let&#39;s actually do this one up here so physically we&#39;re running out of room up there so let&#39;s do the six one up here so the sixth one we&#39;re going to damage right here okay so let&#39;s make our visual fields same thing we got to make this into four parts we&#39;re going to cut it up like this cut them up like this in fear retinal fibers and this is from this is actually on the left side so this is the left inferior retinal fibers so that means that it&#39;s receiving information from the right visual field okay so we already know it&#39;s right visual field that are being affected done okay and again this is left eye and this is right eye we know that the right visual fields are going to be affected but we know it&#39;s the inferior part of the retina that&#39;s being affected if the inferior part of the retina is being affected we&#39;re losing vision in the superior plane so now what&#39;s going to happen we&#39;re losing the right visual fields but on the inferior the superior plane so now you&#39;re losing this part here what is this one called this is called right superior quadrant Hemi and Opia okay that&#39;s that one so right superior quadrant hemianopia and if you get this one then you should be able to get the same thing if I damaged this other side okay it would just be the exact opposite maybe left superior quadrant hemianopia if I damage this soupy retinal fibers of this side on the left side then I&#39;d have right inferior quadrant hemianopia the same thing okay holy sweet goodness now we have this seventh one here seventh one if I damage this whole thing you know I never even told you what the heck these pink structures are I&#39;m so sorry about that these pink structures here all of these this one here this one here from both sides they&#39;re called optic radiations they&#39;re called optic radiations so these superior retinal fibers and in theoretical fibers are make up what&#39;s called the optic radiations or you can call this the Janicki low calcarine tract and the reason why it&#39;s coming from the Janicki body to the calcarine fissure okay so these optic radiations let&#39;s say that I damage the right optic radiation so I damage my right optic radiations okay right optic radiations bricking going okay so if that&#39;s damaged let me get rid of this right here so I can make room here same thing let me write draw this right here this right here but because not affecting it&#39;s a losing if you&#39;re losing both the quadric so we&#39;re just going to make it to the boxes here if I damage this one and I damage this one what do I remember anything that&#39;s on the right side I&#39;m losing it from the left visual fields so if I&#39;m losing it from the left visual fields then what must be happening here I&#39;m losing it from both the superior and for your planes so that means I&#39;m losing all of the information from the left visual field of the left eye and the left visual field on B right eye what do we call this one if you remember doesn&#39;t it seem very very familiar it looks just like this one right over here what is this one over here called this one was called left homonymous hemianopia it&#39;s the exact height vaccine-type here so is called left homonymous hemianopia one and we&#39;re thankfully done here let&#39;s say that you damage a specific part of the occipital cortex you know there&#39;s two arteries that are supplying the occipital lobe here there&#39;s what&#39;s called the posterior cerebral artery which is a part of the Circle of Willis and there&#39;s another one here called the middle cerebral artery which is actually a branch of the Circle of Willis let&#39;s say that you develop some type of most common cause here some type of lesion with the unlocks epital lobe is you develop a lesion here within the posterior cerebral artery you still have blood that can supply the occipital lobe from the middle cerebral this is the middle cerebral artery you still can get blood to the occipital lobe now there&#39;s a specific area in occipital lobe that picks up very very acute vision that is within the macula of the eye okay so there&#39;s the macular region of the occipital lobe if the post a cerebral artery is occluded you might affect the blood flow to the macular region of the occipital lobe well because we have these middle cerebral arteries they&#39;re still going to give blood to the macula so what happens here something really freaking weird is because you spared the macula by giving a blood flow from the middle cerebral artery you spared the macular region the occipital lobe then whenever you do their visual fields so again here&#39;s the left here&#39;s the right eye split up their visual fields here into left and right there&#39;s something really thing a weird here that we can actually include into this I can put a circle here and this circle here is representing the center of that part in the eye you know how we have the macula lutea where the fovea centralis is the highest concentration of cones what happens is if you can actually spare that macula because the posterior artery is occluded but the middle cerebral artery is still getting blood flow to this area this area of the macula is the this area of the occipital lobe where the macular impulses are coming to that will be spared but again everything is on this right side so if the right part except a little bit of damage anything from the left visual field will be lost so what am I going to lose I&#39;ll lose this part of the left visual field and I&#39;ll lose this part of the left visual field but guess what I will not lose I won&#39;t lose this specific area right there which is actually called the macula region so this is called it looks like oh isn&#39;t this left homonymous hemianopia yeah this right here is called left homo 9ms hemianopia but with sparing of the macula with sparing of macula okay that&#39;s the whole purpose of this all right so in this video we talked about the visual field processing we talked about the visual field processing we talked about the actual visual pathway and we talked about associated lesions that could develop within the different parts of this visual pathway guys I really hope all of this made sense I really really really do hope that you guys did enjoy it and I hope it helped if it did please hit the like button comment down the comment section and please subscribe alright engineers as always until next time

I&amp;#39;m in Aries in this video we&amp;#39;re going to talk about specifically the visual pathway so we&amp;#39;re going to take how the light hits the retina and we&amp;#39;re going to take it through the optic nerve and all the other different process if you guys have already watched our video on the phototransduction cascade that&amp;#39;s going to be very very important that you do that before we get into this visual pathway because we already talked about exactly how those light rates got converted into chemical changes and then electrical changes and how they went down the axon to the ganglion cells which basically made up the optic nerve all right so now we&amp;#39;re going to have two eyeballs right this is the we&amp;#39;re going to say this the left eyeball and this is the right eyeball okay now first things first what I want us to try to imagine if we&amp;#39;re gonna put a lot of different concepts together when you guys are looking you guys are like looking at anything around you we our eyes are so amazing that they can pick up different types of visual fields so for example this is the right visual field or the right visual field and this is the left eyes visual field okay so what is this one right here this is the right eyes visual field and this one over here is the left eyes visual field okay now with in the visual field you have two different components of this visual field we&amp;#39;re going to say this is the nasal so since your you&amp;#39;d have your honker right there pretend this is your nose okay so pretend this structure here is your nose okay since this is the nose these two structures that are near the nasal region this is the nasal component of the visual field alright so this is the nasal component of the visual field and then this one over here would be near the temple so this is the temporal component of the visual field and this over here is going to be the temporal component of the visual field okay now to make it easy though now that we know that this is what it is it&amp;#39;s nasal and the temporals these words are going to get interchanged a lot so I do not want to confuse you guys so what I&amp;#39;m going to do is for the sake of it is I&amp;#39;m going to switch nasal and since this is the right visual field this is what gets confusing the right visual field has a left visual field and a right visual field okay so the right eye has a left visual field and a right visual field so we&amp;#39;re going to say this is the left visual field and this is the right visual field okay so I just want to make it as simple as I possibly can here this whole right eye is going to have two fields it&amp;#39;s going to have the right visual field and last visual field same thing this left eye is going to have two visual fields it&amp;#39;s going to have a left visual field and a right visual field okay simple as that now we&amp;#39;re going to be able to kind of do this a lot easier now so instead of using the words nasal and tempore but understand those words because it&amp;#39;s going to be important lesions okay let&amp;#39;s say first off when we&amp;#39;re looking out let&amp;#39;s say that this part of the retina there&amp;#39;s two parts of the retina so this is the right eye this part of the retina is closest to the temple or the right temple right so we&amp;#39;re going to call this part of the retina we&amp;#39;re going to call this the temporal Hemi retina okay that&amp;#39;s a temporal Hemi retina now here&amp;#39;s what gets really funky the temporal Hemi retina is receiving light rays from the left visual field okay so from here this part here this left visual field is hitting this part of the retina okay so if light rays from the left visual field are hitting this part of the hit retina that temporal heavy right now but then the what is this one this one is close to the actual nose so since it&amp;#39;s close to the nose this is called the nasal right Hemi retina so it&amp;#39;s called the nasal hemorrhage now and it&amp;#39;s called the temporal Hemi retina the nasal hemorrhage now is receiving light from the right visual field so the nasal Henry retina is getting hit with light from the right visual field all right so just to make sure we&amp;#39;re clear left visual field hits the temporal hit me right now and the right visual field hits the nasal heavy retina sweet deal same thing would happen up here what would this one be this one right here would be the temporal Hemi retina want to put a char here and this right up here is going to be the nasal Hemi retina okay and same thing nasal heavy rain is going to be receiving visual field from left visual field so it&amp;#39;s going to be getting it from the left visual field and then the temporal Hemi retina on the left eyeball is going to be receiving it from the right visual field okay now that we&amp;#39;re done with that what happens with these fibers here&amp;#39;s what I want you to remember anything from the right goes to the left anything with the left goes to the right that&amp;#39;s it anything that&amp;#39;s coming from the left okay well this temporal Hemi retina this is on the right eyeball okay so this is the right eyeball it&amp;#39;s picking up information from the left visual field well anything from the left has to go to the right oh so these should stay on the same side then so these fibers right here they should not go and cross over to the other side they should stay on this same side so they&amp;#39;re going to come down the optic nerve and you know what happens the two optic nerves actually come together they come together and form this big old structure that you kind of see right here I&amp;#39;m actually not going to do it in brown here because I&amp;#39;m going to use this brown a lot I&amp;#39;m just going to say here at this point here where the two optic nerves are connected all of this part right here this whole thing is called the optic chiasma and the optic chiasma is where the right optic nerve and the left optic nerve come together right near the pituitary gland so this is right here the pituitary gland okay now what happens here the fibers from the temporal Hemi retina which is receiving it from the left visual field we said anything from the left visual field will go to the right eye okay so this is going to cross means lock of the cross it&amp;#39;s going to stay on the same side so is going to come down the right optic nerve where the optic chiasma is it&amp;#39;s not going to cross it&amp;#39;s going to stand the same side and it&amp;#39;s going to move down this structure right here which is called the optic tract and we&amp;#39;re going to stop right there okay so what is this structure right here this long tube-like structure here this whole tube like structure here is called the optic tract so this would be the right optic tract what do you think this one is this is the left optic tract and this is the optic chiasma okay now let&amp;#39;s follow this nasal hemorrhage huh well the nasal henry retina is receiving information from the right visual field well anything from the right goes to the left so this is got a cross so these fibers from the nasal Heming retina it&amp;#39;s going to come through the optic nerve the right optic nerve and it&amp;#39;s going to cross at the optic chiasma and go over here to the opposite side it&amp;#39;s going to come over to what optic tract it&amp;#39;s going to come over here to the left optic tract and it&amp;#39;s going to come right to there and that&amp;#39;s what we&amp;#39;ll stop at that point okay now we understand this this should be a lot easier now let&amp;#39;s do this one nasal hit me right now it&amp;#39;s receiving what it&amp;#39;s getting hit from the last visual field well if it&amp;#39;s receiving information for the left visual field anything from the left has to go to the right okay well this is on the left that means it has to cross over here so it&amp;#39;ll come down the left optic nerve but then instead of going on the same side it&amp;#39;s going to cross over it&amp;#39;s going to become contralateral right and these fibers are going to come over here and they&amp;#39;re going to move all the way over here on this side and come right there okay so all the things that are coming from the left visual field on the left nasal Hemi ratney is going to be coming from the left visual field it&amp;#39;s going to be taking that information on the right optic tract and into this area that we&amp;#39;re going to talk about in a second let&amp;#39;s keep going temporal Hemi retina it&amp;#39;s going to be receiving information from the right visual field right of the left eye so it&amp;#39;s going to be receiving from the right visual field one new thing from the right goes to the left where are they on the left side of the eye let&amp;#39;s just keep it up see lateral so these fibers here are going to come down the left optic nerve it&amp;#39;s not going to cross at the optic chiasm it&amp;#39;s going to stay on the same side and move down the left optic tract and then to this area right here okay so these are your fibers that are crossing and these are the ipsilateral fibers so what do these fibers right here called these fiber gears that are staying on the same side are your itsy lateral fibers these are the ipsilateral fibers and these fibers here that are crossing are called your contralateral fibers contra lateral fibers okay all right sweet deal now that we know that let&amp;#39;s keep it bring or keep bringing it to where we&amp;#39;re going to go next so we already went from these hmmm your retinues from the visual fields we followed it down their optic nerves the optic chiasm we folder down the optic tract we see the FC lateral fibers and we know the contralateral fibers sweet deal what happens is from this optic tract it&amp;#39;s going to come to a special area in the thalamus I&amp;#39;m actually zooming in on the specific nucleus on that ballast but let&amp;#39;s say pretend here that I have I draw kind of like a little view of the thalamus it has kind of like this like piece like symbol a little bit and it kind of looks like this and what happens is it has a special nucleus coming off of it right it has a special nucleus coming off of it like this it&amp;#39;s called the lateral geniculate nucleus what I&amp;#39;m doing is I&amp;#39;m taking the lateral geniculate nucleus and just zooming it on it okay so this right here is the thalamus but a special nucleus of the thalamus is called the lateral geniculate nucleus I&amp;#39;m taking a large Nikolov nucleus and zooming in on it okay so that we&amp;#39;re clear so this is lateral geniculate nucleus it has a total of six layers six layers so let&amp;#39;s layer this one two three four five six and the same thing over here one two three four five six why am I telling you this because any epsy lateral fibers go to two three and five layers so FC lateral fibers within the lateral geniculate nucleus are going to go to layers two layers three and layers five so what does that leave for the contralateral the contralateral is left with going to one four and six so then the contralateral fibers will go to one four and six okay so now it comes in to this area right so I&amp;#39;m going to kind of make these different because obviously the same color but look here from this one this is the contralateral so this one is the contralateral fiber the contralateral fiber goes to what one four and six so if I were to do it let&amp;#39;s actually just make it a different color from this point so that we&amp;#39;re not confusing this so now I&amp;#39;m going to come from this contralateral fiber it&amp;#39;s going to be maroon it&amp;#39;s going to give connections to what for it&amp;#39;s going to give connections to six and it&amp;#39;s going to give connections to one then the ipsilateral fibers are going to go to two three and five okay and the same thing is going to happen over here let&amp;#39;s say that I just for the sake of it I do the same thing over here at the FC lateral fibers and the contralateral fibers over here so this one here is the contralateral I&amp;#39;m going to keep the contralateral maroon contralateral goes to what it goes to six it goes to four and it goes to one if see lateral fibers are going to go to two three and five now from this they&amp;#39;re going to come out of lateral geniculate nucleus so these fibers are going to be coming out of the lateral geniculate nucleus so the terminate in this area some of the fibers we&amp;#39;ll talk about when we talk about the pupillary light reflex some of these fibers can actually go from the lateral geniculate nucleus and into the specific area of the midbrain there go into the midbrain and there&amp;#39;s two structures in the midbrain that&amp;#39;s a very important one is going to be right here called the superior colliculus it&amp;#39;s going to give off some branches that can go there so some of the fibers can go here to the superior colliculus so some of the fibers can come to the superior colliculus but a really really important one is going to be just anterior to the superior colliculus there&amp;#39;s a very important nucleus here called the pre tectal nucleus so really important nucleus here called the pre tectal nucleus and we&amp;#39;ll talk about this one how it&amp;#39;s connected with your basically the constriction of the pupil okay so that&amp;#39;s the protective nuclei we&amp;#39;re not gonna talk about that now we&amp;#39;re going to talk about the rest of this pathway okay I suppose you realize that some of these fibers can go into the midbrain however most of the fibers are going to continue let&amp;#39;s do this in pink now let&amp;#39;s bring it all nice and nice and pretty alright so coming out of the lateral geniculate nucleus there&amp;#39;s going to be two types of fibers one is going to run through the temporal lobe and come to this area of the occipital lobe so you see this right here all this structure that we have right here this is representing the occipital lobe so this is the occipital lobe and this would technically be on the left side and this is the occipital lobe and this would be on the right side and what&amp;#39;s it separating them is what&amp;#39;s called the calcarine fissure right so it&amp;#39;s called the calcarine fissure right here I&amp;#39;m not going to do that I was remember it&amp;#39;s the calcarine fissure all right now some of the fibers from ladder&amp;#39;s nickel a nucleus move through what&amp;#39;s called the temporal lobe so some of them move through an area of the brain called the temporal lobe to go to the occipital lobe some of the fibers actually move through the parietal lobe to come to the occipital lobe so what&amp;#39;s the other one right here this would be the parietal lobe and then the same thing would happen over here so if we just continuously do this because it&amp;#39;s going to be important that we make this very very consistent here one&amp;#39;s going to remove through the temporal lobe to come to the occipital lobe and one&amp;#39;s going to move through the parietal lobe to come to the occipital lobe okay sweet stinking deal this is the temporal and this one right here would be the trial the reason why I&amp;#39;m being so picky is because these ones have different they&amp;#39;re different types of fibers these are actually the ones that are moving to the parietal lobe these are called the superior retinal fibers they also call it baram&amp;#39;s loop so some bærum do musta came up with it right so these superior retinal fibers are actually also called barrels and they&amp;#39;re moving to the parietal lobe these ones that are moving to this temporal lobe are the inferior retinal fibers so these are the inferior retinal fibers and this is actually called meyers loop so again some some dude named meyers came up with that right so again inferior retinal fibers and this is a part of meyers loop and it&amp;#39;s important because it talks about and when we get to lesions right okay now these are moving to deprive the lobe they&amp;#39;ll come to the occipital lobe and they&amp;#39;ll go to a specific area specific like part of the occipital lobe and that specific area of the occipital lobe is actually called the striate cortex and the striate cortex is basically the primary visual cortex so the striate cortex is basically the primary visual cortex this is where the perception of these visual stimuli become what we see okay so how we perceive these different types of images okay so that&amp;#39;s an important thing to know these fibers are coming to the striate cortex of the occipital lobe which is the primary visual cortex where their perception of these visual sensations are actually occurring all right now that we&amp;#39;ve done that I need us to apply some visual like correlations that there are certain types of lesions and different fibers here okay now the only reason I&amp;#39;m saying that is to know this is great but why do we need to notice because we need to apply it to clinical settings so let&amp;#39;s say here that I have a couple different lesions I&amp;#39;m going to make it as simple as simple as possible let&amp;#39;s keep all the colors here let&amp;#39;s do it in like this maybe we&amp;#39;ll do in purple here will represent the lesion by purple I&amp;#39;ll say there&amp;#39;s a lesion here so that&amp;#39;s leaves you&amp;#39;re number one okay then let&amp;#39;s say that there&amp;#39;s a lesion right here so there&amp;#39;s a lesion right here this is leisure number two then let&amp;#39;s say that there&amp;#39;s actually going to be a lesion on the outside here and outside here at the same time so let&amp;#39;s say that this is lesion number three then let&amp;#39;s say that we have a lesion that&amp;#39;s occurring right here leisure number four and then we&amp;#39;ll have a lesion here like lesion number five lesion six and then what happens if we had damaged the whole thing lesion seven and the last thing is what if we develop some type of damage to the occipital lobe and that will be lesion eight so eight total lesions is what we&amp;#39;re going to talk about here okay here we go if the right optic nerve is damaged let&amp;#39;s do our visual fields here let&amp;#39;s get our little visual fields here keep it super super simple here here&amp;#39;s our visual field for the right eye so we&amp;#39;re gonna have two visual fields here one right there for the right eye one right there for the left eye and we&amp;#39;ll separate into the left visual field and right visual fields so again this is for the left eye this is for the right eye if this right here is damaged this right here is damaged this optic nerve then I&amp;#39;m losing what I&amp;#39;m losing the certain types of visual sensations from the right visual field of the right eye okay so right visual field of the right eye it&amp;#39;s gone I have no vision in this area so let&amp;#39;s go ahead and shade that in this whole thing go on I got no vision there I developed some scotoma right there I lose all my vision in that that visual field then any of the information all the visual sensations that are coming from the left visual field of the right eye that&amp;#39;s gone - alright see ya see you later that&amp;#39;s it I lose all the information from these two visual fields of the right eye what do I develop I develop mono ocular blindness which side right sided mono ocular blindness so what is this called right here mono ocular blindness or an obeah so we can say that this is right side mono ocular blindness or an opium okay simple of that and this would be lesion number one so Louise you&amp;#39;re number one if you damage the optic nerve you&amp;#39;re going to have complete right side of the eye mono ocular blindness no vision there second one let&amp;#39;s say that you develop a pituitary tumor and it compresses the medial part here of the optic chiasma it&amp;#39;s compressing the contralateral fibers here so let me make two visual fields here okay so this one is going to be again this is for your left eye and this is for your right eye well it&amp;#39;s going to be affected here if I damage the contralateral fibers what does that mean okay let&amp;#39;s follow this one over your nasal Hemi ratney I&amp;#39;m losing the visual sensations from the left visual field of the left eye that&amp;#39;s gone see you later they&amp;#39;re like hey let&amp;#39;s do this in a different color here like this this is gone okay so I lose that sight I lose my temporal visual field or the left visual field of that left eye right then what I&amp;#39;m also damaging these fibers and if I damage these fibers this is picking up information from the right visual field of the right eye so now this is gone so I&amp;#39;m losing my temporal vision on the right eye because I&amp;#39;m losing my vision and both the visual fields two temporal fields right the temporal fields this is called they got a heck of a name for this one they call it by temporal Hemi a no Pia or enough and they not hemianopsia you can even say like that so bitemporal hemianopia okay that&amp;#39;s done what about three okay let&amp;#39;s say that there&amp;#39;s some type of you know the internal carotid arteries kind of run nearby here so there&amp;#39;s actually internal carotid arteries that runs very very near this optic chiasma right here let&amp;#39;s say that for some reason these guys develop like an aneurysm right and they compress these outer parts here be careful you have an aneurysm of both of them and it&amp;#39;s actually compressing both these fibers what fibers the ipsilateral fibers so now let&amp;#39;s draw your two visual fields here this is four three okay this is your left eye this is your right eye okay if it&amp;#39;s damaging the ipsilateral fibers you&amp;#39;re going to lose information from the nasal field of the left eye and if you&amp;#39;re damaging this FC lateral fiber you&amp;#39;re going to lose the nasal field of the right eye well that&amp;#39;s by temporal this is going to be by nasal by nasal hemianopia will turn me over and tickle me twisted look at that that&amp;#39;s called by nasal Hemi a Nokia or in nobs synopses right so by nasal hemianopia is the third type of lesion so I&amp;#39;d be number three so this is number three here this was number two and this was number one okay now off the number four if you lose number four let&amp;#39;s make our visual fields here and I&amp;#39;ll do it like this again left eye and right eye left and right visual fields bye damage these bad boys all this right optic tract let&amp;#39;s follow it the right optic tract let&amp;#39;s follow this one first okay come over here come over here come over here okay Mazal heavy right knees not going to work so I&amp;#39;m gonna loop my would lose the left visual field of my left eye so last visual field of the left eye gone that&amp;#39;s gone okay follow this one if we follow this one follow this one for this one we go over to the temporal Hemi retina which I&amp;#39;m losing it from the nasal side of my right eye that socks and if I loose it from the nasal side of my right eye what would I call this one they got a heck of a name for this one all right it&amp;#39;s a little tight it&amp;#39;s a tiny bit confusing but I want you guys to remember remember we said that this was the temporal and the nasal nasal temporal right we also said that we could say that this is the left visual field in the right visual field and left eye left visual field of the right eye and right visual field of the right eye what did I lose I lose both of my left visual fields of both eyes so because of that they call it left homo nyam is Hemi and Opia why not so that is the fourth type of lesion and you would have the same thing at that hashing on the left optic tract except to be right homonymous hemianopia so again this is lesion number four it&amp;#39;s called left homonymous hemianopia now let&amp;#39;s say that we get back here we get back here now these are the these are the frackers these are the one that can be a little bit confusing here let&amp;#39;s say that I do number five here right so now I damage this part the actual what loop the baram&amp;#39;s loop which is called the superior retinal fibers before I move on let me make a mini little diagram here so that I can really really make sense of this we can split the visual fields up like we did over there but we can actually if we really want to be very very specific let&amp;#39;s say I make here this is my left visual field my right eye left eye sorry left eye right eye remember how we split it into a left visual field and a right visual field for both of them guess what we can split it into a upper left upper right lower left lower right okay now let&amp;#39;s say everything up above this part that I have in blue this is all the superior part right so this is the superior part of the retina all this down below is the in fear red now when we&amp;#39;re talking about the superior etta no fibers okay now I&amp;#39;m looking at the eye like from my eyes like imagine here I have my eyeball like this I&amp;#39;m actually fixing my eye and looking straight down like this into the eyeball okay let&amp;#39;s pretend for a second though that I look at it like this now I take this eyeball here and let&amp;#39;s say up here I have my superior part of the retina and then down here I have the inferior part of the retina the superior part of the retina is getting hit with light rains that&amp;#39;s coming from the lower visual fields and then the inferior retina is getting hit with light range that&amp;#39;s coming from the superior visual field it&amp;#39;s frickin crazy I know but I&amp;#39;m sorry that&amp;#39;s how it works so now when we make this one we have to make it like this here&amp;#39;s left eye right eye we have to split it like this but then into fours okay superior quadrant in your quadrant okay okay now let&amp;#39;s let&amp;#39;s think about this if this suit we damaged this right side the right superior retinal fibers if the right superior retinal fibers are damaged remember anything from the right side is coming from the left eye or the left visual field so again anything that&amp;#39;s coming from this is coming from the left visual field anything that&amp;#39;s on the right eye is coming from the left visual fields so want to make sure that we get that completely clear if this is damaged the superior edge no fibers then I&amp;#39;m losing the vision within the inferior visual field on the left side okay so we already know that I&amp;#39;m losing the actual left visual field that&amp;#39;s already clear does anything from the right eye is picking up information from the left visual fields so all of this is gone the left side but remember superior at no fibers only pick up the information from the inferior visual field so really we&amp;#39;re only losing this part here and we&amp;#39;re only losing this part here so because I&amp;#39;m losing vision within the lower quadrant of the left visual field we call this what this one&amp;#39;s a heck of 1 to left inferior quadrant Hemi and Opia okay so left inferior quadrant hemianopia and it&amp;#39;s because we&amp;#39;re losing our vision within the left visual field and in the inferior plane okay then if we did a lesion here in the sixth one right so we said that we damage this six one here so let&amp;#39;s actually do this one up here so physically we&amp;#39;re running out of room up there so let&amp;#39;s do the six one up here so the sixth one we&amp;#39;re going to damage right here okay so let&amp;#39;s make our visual fields same thing we got to make this into four parts we&amp;#39;re going to cut it up like this cut them up like this in fear retinal fibers and this is from this is actually on the left side so this is the left inferior retinal fibers so that means that it&amp;#39;s receiving information from the right visual field okay so we already know it&amp;#39;s right visual field that are being affected done okay and again this is left eye and this is right eye we know that the right visual fields are going to be affected but we know it&amp;#39;s the inferior part of the retina that&amp;#39;s being affected if the inferior part of the retina is being affected we&amp;#39;re losing vision in the superior plane so now what&amp;#39;s going to happen we&amp;#39;re losing the right visual fields but on the inferior the superior plane so now you&amp;#39;re losing this part here what is this one called this is called right superior quadrant Hemi and Opia okay that&amp;#39;s that one so right superior quadrant hemianopia and if you get this one then you should be able to get the same thing if I damaged this other side okay it would just be the exact opposite maybe left superior quadrant hemianopia if I damage this soupy retinal fibers of this side on the left side then I&amp;#39;d have right inferior quadrant hemianopia the same thing okay holy sweet goodness now we have this seventh one here seventh one if I damage this whole thing you know I never even told you what the heck these pink structures are I&amp;#39;m so sorry about that these pink structures here all of these this one here this one here from both sides they&amp;#39;re called optic radiations they&amp;#39;re called optic radiations so these superior retinal fibers and in theoretical fibers are make up what&amp;#39;s called the optic radiations or you can call this the Janicki low calcarine tract and the reason why it&amp;#39;s coming from the Janicki body to the calcarine fissure okay so these optic radiations let&amp;#39;s say that I damage the right optic radiation so I damage my right optic radiations okay right optic radiations bricking going okay so if that&amp;#39;s damaged let me get rid of this right here so I can make room here same thing let me write draw this right here this right here but because not affecting it&amp;#39;s a losing if you&amp;#39;re losing both the quadric so we&amp;#39;re just going to make it to the boxes here if I damage this one and I damage this one what do I remember anything that&amp;#39;s on the right side I&amp;#39;m losing it from the left visual fields so if I&amp;#39;m losing it from the left visual fields then what must be happening here I&amp;#39;m losing it from both the superior and for your planes so that means I&amp;#39;m losing all of the information from the left visual field of the left eye and the left visual field on B right eye what do we call this one if you remember doesn&amp;#39;t it seem very very familiar it looks just like this one right over here what is this one over here called this one was called left homonymous hemianopia it&amp;#39;s the exact height vaccine-type here so is called left homonymous hemianopia one and we&amp;#39;re thankfully done here let&amp;#39;s say that you damage a specific part of the occipital cortex you know there&amp;#39;s two arteries that are supplying the occipital lobe here there&amp;#39;s what&amp;#39;s called the posterior cerebral artery which is a part of the Circle of Willis and there&amp;#39;s another one here called the middle cerebral artery which is actually a branch of the Circle of Willis let&amp;#39;s say that you develop some type of most common cause here some type of lesion with the unlocks epital lobe is you develop a lesion here within the posterior cerebral artery you still have blood that can supply the occipital lobe from the middle cerebral this is the middle cerebral artery you still can get blood to the occipital lobe now there&amp;#39;s a specific area in occipital lobe that picks up very very acute vision that is within the macula of the eye okay so there&amp;#39;s the macular region of the occipital lobe if the post a cerebral artery is occluded you might affect the blood flow to the macular region of the occipital lobe well because we have these middle cerebral arteries they&amp;#39;re still going to give blood to the macula so what happens here something really freaking weird is because you spared the macula by giving a blood flow from the middle cerebral artery you spared the macular region the occipital lobe then whenever you do their visual fields so again here&amp;#39;s the left here&amp;#39;s the right eye split up their visual fields here into left and right there&amp;#39;s something really thing a weird here that we can actually include into this I can put a circle here and this circle here is representing the center of that part in the eye you know how we have the macula lutea where the fovea centralis is the highest concentration of cones what happens is if you can actually spare that macula because the posterior artery is occluded but the middle cerebral artery is still getting blood flow to this area this area of the macula is the this area of the occipital lobe where the macular impulses are coming to that will be spared but again everything is on this right side so if the right part except a little bit of damage anything from the left visual field will be lost so what am I going to lose I&amp;#39;ll lose this part of the left visual field and I&amp;#39;ll lose this part of the left visual field but guess what I will not lose I won&amp;#39;t lose this specific area right there which is actually called the macula region so this is called it looks like oh isn&amp;#39;t this left homonymous hemianopia yeah this right here is called left homo 9ms hemianopia but with sparing of the macula with sparing of macula okay that&amp;#39;s the whole purpose of this all right so in this video we talked about the visual field processing we talked about the visual field processing we talked about the actual visual pathway and we talked about associated lesions that could develop within the different parts of this visual pathway guys I really hope all of this made sense I really really really do hope that you guys did enjoy it and I hope it helped if it did please hit the like button comment down the comment section and please subscribe alright engineers as always until next time

Transcript for:Visual Pathway Lecture Notes

Transcript for:
Visual Pathway Lecture Notes