I found out only a few months ago that I don’t have a Corpus Callosum. I am 48 now. I am also near sighted and far sighted and it can’t be corrected because my eyes work independent of each other. There is a question there but I can’t quite think of it. Great video.
I really found myself thinking I am developing scholarly humour when giggling at your comment: "Wow, I've looked at a lot of faces today, my right hemisphere sure is tired" haha. Thank you so much for your clear and concise video, I have subscribed and can't wait to watch more! How blessed are we as modern psych students to have youtube to help us learn in ways that suit us better than our studies. Cheers.
I wonder if a person with a split brain, is really two separate entities, but because they perceive the same information most of the time, that it rarely effects them.
I had this surgery, partially separated, not fully separated. Had trouble feeling one side of my body after the surgery and the disconnection syndrome absolutely sucked.
I suffer from Atonic "drop" seizures almost daily and are very dangerous, not the falling but what you fall on or into. I've suffered from multiple broken noses, fingers, lost about 12 teeth before just getting a partial denture. 2nd degree burns on my face, road rash, and countless concussions and stiches from falling like a sack of potatoes. I had never heard of this operation until 2 days ago. The side effects are kind of scary but falling on a curb just right and breaking my neck also scares me. I still haven't decided the lesser of two evils.
Jeremy, did you end up doing this procedure? My daughter's epilepsy team is suggesting it for her. She also has drop attacks several times a day and is always showing some sort of bruise/cut/scrape/burn on her face at a given time. She is only 5.
3:30 Are you completely sure about this example of the left brain specialization on language production given motor/tactile input? I thought the original study only showed that it works this way only when the input in visual. Motor input -> comprehension -> language output vs. visual input -> comprehension -> language output could technically be two separate pathways.
This tactile input example is based on Roger Sperry's early work with split-brain patients in which he tested both visual and tactile presentations. Here's a somewhat lengthy quote from Sperry (1968) describing these tactile tasks: "A similar separation in mental awareness is evident in tests that deal with stereognostic or other somesthetic discriminations made by the right and left hands, which are projected separately to the left and right hemispheres, respectively. Objects put in the right hand for identification by touch are readily described or named in speech or writing, whereas, if the same objects are placed in the left hand, the subject can only make wild guesses and may often seem unaware that anything at all is present. As with vision in the left field, however, good perception, comprehension, and memory can be demonstrated for these objects in the left hand when the tests are so designed that the subject can express himself through nonverbal responses. For example, if one of these objects which the subject tells you he cannot feel or does not recognize is taken from the left hand and placed in a grab bag or scrambled among a dozen other test items, the subject is then able to search out and retrieve the initial object even after a delay of several minutes is deliberately interposed." Hopefully this helps address your question, you can find the original paper by Sperry here (above paragraphs on page 726 / page 4 of the pdf): sci-hub.st/10.1037/h0026839
Yes, good point, I would certainly agree that the wiring is really for binocular depth perception, not redundancy for losing an eye. But imagining losing an eye and still having information sent to both hemispheres can make the concept that vision is split by visual field rather than by eye easier to remember. Thanks for commenting!
I have some questions on this topic and hope you know the answer. Are there any known cases, in which the right side of the brain begins to develop a better processing of speach in order to communicate? How fast can the left side solve complex problems without the other half? Was there ever an attempt to create a new connection between the brain halfes of a person born without an Corpus Callosum? Are there any scans indicating weird behavior in the right half of the brain, since it is no longer able to express itself/influence its surrounding?
So when the left hemisphere makes up that story about the key, does the person's consciousness seem to sincerely believe what they're saying? Because they obviously cannot draw from memory. Is it more like the concocted event of the key used as a screwdriver is more of a hunch?
This is a good question that I don't really have a full answer to. The general explanation seems to be that the left hemisphere is good at generating explanations for behavior, but the person's belief or doubt in that explanation may be difficult to assess. What we even mean by the "person" may be challenging; the right hemisphere would certainly disagree if it could, but can the left hemisphere doubt its own explanations? I'm not sure what you mean when saying they can't draw from memory though. In my example it's possible that he really had used a key as a screwdriver recently and remembered that, but this still doesn't make it the reason that the left hand drew a key (it drew a key because the right hemisphere saw a key). The left hemisphere attempts to generate a plausible explanation for this event and it may be based in accurate memories, but it's not the real reason, because the experiment design means the left hemisphere can't know the real reason that he drew a key (or whatever other stimulus). The same concept of the left hemisphere generating explanations may be true for non-split-brain people in everyday life too. If someone were to suddenly quiz you on your daily behaviors, you might find yourself coming up with plausible explanations that might not really be accurate. If I were to ask you why you chose a particular menu item or why you chose to stand up from the couch at a particular moment, you might be able to come up with a reasonable justification but that doesn't necessarily mean it was the real reason for the behavior. But it might be very tough to assess how much you sincerely believe those explanations that you generate. I think this leads us to larger questions about the challenges of understanding consciousness that I can't fully address 😅 Thanks for commenting!
If a person is born without the corpus callosum (Agenesis of the Corpus Callosum), do they exhibit the same inability to identify an object that is placed in their left hand or does the brain learn to compensate as they grow up? Is severing the corpus callosum in an adult different than a baby being born without it?
I don't think that this situation usually occurs for those with agenesis of the corpus callosum but there is a lot of variation between individuals and differences in the degree of connection between the hemispheres. They can usually transfer some information between hemispheres but this is impaired and often there are problems with coordination. The early split brain studies by Roger Sperry and Michael Gazzaniga demonstrating hemispheric specialization used participants who had undergone surgery to sever the corpus callosum. Agenesis will influence brain development and may cause some tasks to be more distributed across the hemispheres, which won't have occurred in those who have the surgery later in life. For example, savant Kim Peek (who had agenesis of the corpus callosum) developed language processing in both hemispheres, while someone who had the CC severed in adulthood would likely only have language processing in the left hemisphere.
I may have some ideas that could explain most of the things in this video related to the duality of all existing things and more specifically, the 2 halves of the brain. My theories seem to also correlate and explain loads of things related to religion and spiritual practices, dreams, REM-sleep and much, much more. If you read this and are like me seeking answers please contact me as I am not sure where or how to describe and debate all of this. This phenomenon probably explains things like dreaming, REM-sleep and many religious practices and rituals not to mention subconsciousness (left)/ and consciousness (right) itself. Why the serious ** is not more energy put into this??!!?!?! It is probably the key to all these questions and more. I also speculate it may even be related to the key of dealing with cancer. Some examples would be the father, the son and the holy spirit (Brain 1, brain 2 and both together). It is the central concept of the importance of balance and yin and yang, the third eye and many many more things- I mean just think about this. If you are watching something such as this video or reading a book, you are not directly absorbing the information but actually explaining to yourself in a manner that you can understand. How else can you argue with yourself? Wanting different things at the same time and so on? I also theorize that one part of the brain is responsible for input e.g. the inner world/emotion/perception whilst the other for output or action. We even know that the first multicellular organism was composed of an outer cell that was in charge of survival and finding raw material whilst the inner organism was responsible for breaking down the raw material into nutrients. It is so very obvious and somewhat easy to understand and for me, almost absolutely proven by split brain experiments yet it seems that every single person on earth just takes these findings at face value, are a little bit disturbed by the notion of being "2" beings and move on to other things. It is almost beyond belief that this has seemingly never been discussed more indepth. If you find this resonates with you and you wish to discuss this, please contact me !
Great video! I have a question - why can't split brain patients move their eyes separately (like a chameleon)? Or was their optic chiasm not cut and the eyes are somehow synchronized based on the opposite visual field?
Great question! The oculomotor nerve controls most eye movements and connects both eyes to the midbrain. This is not severed in these patients, so they don't have changes in their eye movements. Thanks for commenting!
What if the corpus is absent, speech is severely impaired and right lazy eye? Are those areas all connected? I'm disappointed I'm just learning this now. My sons favorite catchphrase for the last years has been "I don't know" and I'm learning it's related to his corpus callosum. His entire life he's faced stern disbelief in his apparent laziness towards daily tasks, by family, educators and strangers. Even his parents. Is this possible? To be skilled in something and not in others? I appreciate your input.
It might be possible that those are related but I can't really say. I'm not a doctor or neurologist; even if I knew more specific details I still wouldn't be qualified to offer any sort of opinion or medical advice. My only (non-medical) advice is to try to ask questions and learn as much as you can from the doctors or specialists you talk to while recognizing that the brain is incredibly complex and they may not always be able to provide clear answers or understand exactly how things are related. Sorry I can't offer more specific help and thanks for commenting!
So if a person were asked to draw what they saw with their right hand, according to the example you gave with the screwdriver on the right side and the keys on the left side, that person would be able to draw the keys only? I'm a bit confused.
If the screwdriver is seen in the right visual field then it will be processed in the left hemisphere, which then controls the right hand. So using the right hand, the patient would draw the screwdriver. In this case, since the information is in the left hemisphere, the patient could also say the word "screwdriver" and then both hemispheres would know and then it could be drawn with either hand. This can't be done for information in the right hemisphere though, because the right hemisphere isn't able to produce speech.
I am teaching a little girl that had a split brain surgery due to seizures. We were told that her left brain works. How does this affect her emotional behavior?
In the experiment of the key and the screwdriver, why doesn't the right hemisphere try to communicate to the left hemisphere the correct information, so that the left hemisphere can answer the question "why did you draw a key" without having to invent a story? You are aware of being a "split brain", so why doesn't the right hemisphere try to communicate with the left hemisphere through other means, like using the left hand to write down the reason he previously draw the key. Probably it is a silly question. Sorry for that, but I'm curious
It's not a silly question, I think it's a great one that points out an interesting aspect of these studies. When asked, obviously the question goes to both hemispheres for the split-brain patient so we should wonder why only the left attempts an answer (by speaking) while the right doesn't immediately tell the left hand to start drawing or trying to communicate in some way unless instructed. I don't have an answer, but this could be related to Alien Hand Syndrome, which involves losing control over a hand, usually the left hand (right hemisphere). As for the awareness of being a split-brain patient, this also raises some interesting questions about consciousness because while the person can know and remember this information on a conscious level, it's unclear if this affects other unconscious brain processes. A related question is whether a split-brain patient has two separate consciousnesses (one for each hemisphere) or not, and as far as I know, researchers are still divided on this point - pun intended :)
This video was very clear, but there is still one point that I'm really not getting. With a split brain the two hemispheres are not able to communicate anymore. The only thing that is connecting the two is the optic chiasm. So, the right hemisphere can recognize faces, but can't talk, how does the left hemisphere - who can talk but can't recognize faces - know this when going to their friends and family? Is it because by looking around, the hemispheres transfer the information trough the optic chiasm? Thanks!
You're right, in everyday life split-brain patients are able to move their eyes around and this allows them to send information to both visual fields and thus both hemispheres.
Right, because they travel for some part trough both hemispheres ofcourse. Thanks! This video helped a lot. Will definitely look at more of your videos.
what about movement of his face and mouth. is it left hemisphere? if he feels sides of his head by different hemisphere he may use his tongue to send signals from one to another just touching his mouth differently from inside. what about emotions? are they shared? he may use emotions to send signals from one to other. so left may know what right hand holding by guessing and answering as yes/no. yes happy, no sad. Or something like it. He may use mimics on his face for it. What about meditation?
I just figured he may use his butt cheeks to communicate :-) Left controls right butt cheek, right left butt cheek. So he may send signals this way. Maybe even Morse code lol ) But probably simple yes/no is enough.... Because right can't process language :-( Maybe it's possible to train it some basic language)
Hi Alexander, essentially any spoken responses coming from a split-brain patient are just coming from the left hemisphere since it controls speech. So the left hemisphere certainly seems to have a fairly fully-developed sense of self. The more difficult part is assessing the right hemisphere because communication using language is necessarily simplified. This makes it much harder to really know what's going on in the right hemisphere. Michael Gazzaniga is one of the leading researchers on split-brain patients so you might start with some of his work. Ian McGilchrist has a book on hemispheric specialization which I've heard good things about but haven't had a chance to read yet. Hope this helps!
As both hemispheres are connected to the spinal cord, and the spine has its own neurones, is the brain’s neuroplasticity capable of developing communication between both hemispheres in some fundamental way?
This kind of dramatic rewiring doesn't seem to be possible later in life. While the spinal cord does have connections to both hemispheres, there is specialization of these pathways, sending information from the body to only one hemisphere contralaterally and split-brain patients don't show new pathways developing to send information across hemispheres. That said, neuroplasticity for these pathways may be possible very early in development and there are cases of young children undergoing hemispherectomy (surgical removal of one hemisphere) and having the remaining hemisphere take over some of the functions of the missing hemisphere.
I have a question, it seems that right brain doesn’t act unless prompted. For instance, when you ask the patient to point with the left hand the object he was holding. Could you get more insight into the right Brains “ consciousness” by asking a question and have the patient close his eyes write with his left hand. (Would be favorable if the patient was left handed) thanks
I wouldn't think of it as the right hemisphere not being active, it's processing information but it's limited in how it can communicate that processing. It can't speak so it appears silent while the left hemisphere can respond quickly to verbal prompts. As for writing, I'm not sure how well split-brain patients can write with the left hand since language processing is more limited. Generally I've seen pointing to simple responses with the left hand used, I'd have to look into attempts involving writing.
So what is the difference to lobotomy? I cant really find an answer online , i just dont get how we can view lobotomy as one of the darkest times in medicine ever and then do that. I just thougt we were over cutting up peoples brains without exactly knowing what it does.
Lobotomies were far less precise and made many patients worse off. More modern types of psychosurgery are very rare and are only used a last resort when symptoms are severe and other approaches have failed.
So if an object is shown in the left visual field, the right hemisphere cannot say what it is it saw, but if it saw a face or objects making up a facial pattern from the left visual field, then the right hemisphere can speak and say what it saw? If the left hemisphere specializes in speech and the right hemisphere cannot say specific objects, why can it speak up and say it saw a face? Is it just the way the brain works because the right hemisphere specifically specializes in faces? If the right hemisphere is more visual, why can it say it saw a face but not an object like a key? Love the video, it was very helpful!
The right hemisphere isn't able to control speech, but it has some language processing and the left hand (controlled by the right hemisphere) can indicate responses by pointing. So for something like recognizing a face, the right hemisphere can be shown an image and then be given a choice of what was seen and use the left hand to point to one of the responses. So a face made of books could be shown, then the patient would point to either "face" or "books". The right hemisphere (left hand) will point to "face" while the left hemisphere (right hand) would only identify books because it lacks the ability to recognize the overall face pattern. You can see a demonstration of this with a split-brain patient here: th-cam.com/video/lfGwsAdS9Dc/w-d-xo.html Hope this helps!
The fact that the left hemisphere is good at confabulating, may not be a trivial point. If someone doesn’t have the ideal levels of cross referencing, or is for some reason overly investing in their narration creation modules (on the left) then this may be a deeper level to the description of delusion or mania?
I should clarify that hemispheric specializations aren't trivial when it comes to figuring out how the brain processes information. There's research on activity levels by hemisphere in depression and other disorders that may improve our understanding and perhaps eventually improve treatment options. What I find trivial is popular books and articles encouraging people to do things like "work their right hemisphere" to improve creativity rather than just telling them to "practice tasks requiring creativity". I don't see it as particularly useful to talk about being left-brained or right-brained and this is sometimes used to give an air of scientific credibility just by mentioning the brain. In everyday life we don't have conscious access to each hemisphere's activities and we can't choose to delegate tasks differently once we know about lateralization. So while hemispheric specializations should certainly be investigated and taken seriously, popular books on becoming more left-brained or right-brained should not.
Thank you for the clarification. Yes it would be pseudo scientific to regard abilities/conditions as all reducible to this paradigm of hemisphere imbalance, and that one can improve things by focusing more on the ‘weaker hemisphere’
So the person seems to live a pretty normal life but is that because the left hemisphere does all the communicating and it becomes dominant? Has there been any research on the emotional effects on the right side of the brain? Surely because it lacks the ability to communicate it has some emotional effects on it. Could there be a way to communicate non-verbally to the right side of the brain? Sorry if these questions are stupid, i am not majoring in psych so my knowledge is very limited on the topic, but it is so interesting!
The left hemisphere isn't necessarily dominant because the right hemisphere is still receiving and processing information. The right hemisphere just isn't able to control speech, so it can't talk about that information. Communication with the right hemisphere can take place by using the left hand to point at words (it has some language processing), draw pictures, etc. but this communication is certainly more limited. This makes it difficult to assess what's really going on in the right hemisphere, though the fact that the left hemisphere doesn't seem too bothered by the division suggests that the right might not be either.
I had the wrong patient's brain surgery when I was 17 years old, with absolutely no help at all, for either operations- and I have believed for a long time that they severed the two hemispheres of my brain, because I have a scar going along the middle of my brain, to at least the middle of my head, and another scar where I had the other operation. I have had severe problems with communicating on an emotional level. Not so much for simple situations, such as something like- "please pass the salt", for instance, but very important means of communicating, as I said, on an emotional level. I have had to live with my circumstances for over 30 years, now. I feel as if I was in a glass box, and people could see me, and I could see them, but there was definitely something keeping me from being able to connect- as I said- on an emotional level. Any suggestions that might be able to help me? Thank you.
I'm sorry to hear about your situation. Unfortunately I don't have the expertise to provide specific suggestions and can only suggest you contact medical professionals who might be able to provide more help, thanks for sharing your story here!
@@tiffanyrichardson6698 My family and were never able to find a way to sue. In South Africa- the lawyers and doctors are on the same side. I didn't even get any help with aftercare for the surgeries that I had. I have been in a very bad situation for over 32 years (or it will be 32 years on September 1St). I have also been forced to live an absolutely separated life from my sons- BrianG (nearly 14 years old) and Gregory- (nearly 10 years old- both this month- in a matter of days) who were 5 years old (Brian) and Gregory was 15 months old when they were literally ripped out of my arms and my life. What is so much worse- is that their father was- and is very emotionally and psychologically abusive and how he has treated us (my sons and I by permanently keeping us separated- for what will be 9 years in December). This is excruciating for me beyond words. And their father wants my eldest son vaccinated for the terrible vaccine- which is- or may as well be literal extermination. Please keep my sons in your prayers. I see them- at the most- twice per week- four hours per week- and it is terrible to be forced to live this way. My current husband, Jesse, (who treats me SO much better than their father did for the 10 years we were married)- and I- have tried- with no success- Jesse and I did try to get legal help- and I have tried to get some help with disability- but there is red tape (mostly that the drs. who performed my surgeries in South Africa- destroyed my evidence which shows that the first MRI was not the scan that belonged to me. It is over (or practically 32 years ago- within literal days)- of it being 32 years ago that I had the surgeries. But I still have very bad side effects which makes it nearly impossible for me to get a regular job. I was 17 years old at the time and will be 50 years old next year. This is literally my entire life that my life has been very badly affected. But I miss my sons so much- and it hurts beyond being able to put it to words of how my sons and I have been separated. Please keep them (and us)- and my mom, Claudette in your prayers. My dad passed away just before the PlanDemic started. My mom still lives in South Africa. I have not seen my mom (or my dad- while he was still alive)- for what will be 10 years ago- on August 17 Th. They came for their last visit on the day my youngest son, Gregory- was born. Sorry this is so long, but thank you for your response. May you and your family be blessed. We are living in extra-ordinary times- Biblical- even. It won't be long, now- before Yahshua (Jesus) returns. Help us all if He doesn't. But how can life go on this way for very long?
One thing bugs me. When the right hemisphere is the one that recognizes faces and the left the one that does the speech, how does the right hemisphere tells the left hemisphere what person you're talking to? How could ... in your example ... the person tell you, that he or she saw a face, if the speaking hemisphere can't do that.
The section about this phenomena in Sam Harris' book 'Waking up' fascinated me, so I came here looking for more info. Thank you for an excellent video. I wonder if you have any comments on what this tells us about the nature of consciousness or the self? It feels like it somewhat tramples on notions of the self as a unitary actor in a way that is both intriguing and confusing.
Phillip Wareham I haven't read Waking Up but I'll check it out. As for the nature of consciousness, you're right that it raises the questions of how and why consciousness feels unitary despite containing multiple systems which appear to operate independently. These split brain studies also introduce the question of how much of your sense of self might just be post-hoc explanations of behavior coming from the left hemisphere. Perhaps this can serve as a reminder to think of ourselves as collections of motivations and processes (conscious and unconscious) that somehow converge to create a sense of self that feels unified and in control. One might argue that unity and control are just an illusion, but it seems to me to be a particularly useful illusion and far superior to the chaos of fragmented consciousnesses.
huh? but in the example with Arcimboldo, how can the patient say "I saw a face" if the right hemisphere doesn't have the language center? he knows what it is but can't say it, or am I wrong? or if its a general term like "face" he can say it?
The patient can point to words on the screen (with the left hand) to indicate whether he saw a face or books (or whatever objects the face was made of). The right hemisphere has some basic language processing and can recognize words.
My 15 year old daughter is a high functioning PACC only child. Our daughter only has 20% of her CC in the frontal lobe. Are you saying that if we were to sever this 20% our daughter would have a better chance at a normal life??
Laura Wright Partial (or complete) agenesis of the corpus callosum is different from callosectomy in terms of how the brain has developed over time. I described split-brain patients as appearing "normal" in that one probably couldn't tell they had undergone the procedure but there are still subtle linguistic and social effects of this disconnection (which may also be similar to PACC or ACC). I should also emphasize that I'm not a doctor or neurologist and nothing I discuss in my videos should be taken as medical advice. You might like to read this article in which people with agenesis of the CC discuss their diagnoses:blogs.scientificamerican.com/observations/patients-reflect-on-life-with-a-common-brain-malformation/ Thanks for watching!
As long as the left hemisphere has received the information somehow (if held by right hand previously) then the person would be able to select the object with the right hand (which is controlled by the left hemisphere).
This video is very helpful though o have a question why do we understand what we are seeing by right brain when we don’t have a functional wernickes area in that side
This is a good question and it seems that the right hemisphere does have some basic language processing, even though the left hemisphere is generally where most language processing happens (for most people).
PsychExamReview Ok but only for visual signals we have this language processing right ? Cause we are not able to understand the auditory signals being transferred to our right brain . And does it have to do something with the angular gyrus on that side cause some visual processing do occur there ? I came up with this explanation could u please confirm
@@Doctor_t.f.m As far as I know, split-brain patients must be able to understand some auditory signals in the right hemisphere because the right hemisphere can follow instructions (such as being asked to draw something with the left hand) but I don't know the limits of that processing or whether more complex instructions or questions can be understood. As for the role of the angular gyrus, it seems reasonable it could be involved in recognizing written words and it has been suggested that the right angular gyrus plays a role in understanding spatial metaphors. So that might relate to some language processing abilities in split-brain patients but I haven't looked at specific research on this topic. So I don't know well-supported the metaphor idea is or how it might relate to other language processing in the right hemisphere. I simply don't know and can't really confirm.
PsychExamReview yes you are right about that instruction part but I saw it in GUyton and Hall Physiology and I was confused Like it says here “in a teenage boy with sectioned corpus callousum, only left brain can understand both written and spoken words , however right side of brain could understand the written words but not spoken words “. This got me confused that day
@@Doctor_t.f.mThat is a bit confusing, though it could be the case that there are some individual differences in lateralization of language processing that would mean that not all split-brain patients would be identical in their language abilities for each hemisphere.
Hey PsychExamReview, how does audio work with these type of people? For example, you ask both sides of the brain if the person is religious or not and they give opposite answers, how would this experiment work?
As far as I know auditory messages can't be isolated the way visual messages can be. This is because nerves from each ear are not strictly lateralized and there are connections to the opposite side (contralateral) as well as same side (ipsilateral) hemisphere.
@@HondaS-fk1mi Yes, nerves from one ear go to the midbrain where there are connections leading to the cortex of both hemispheres. I believe there are more connections to the contralateral side than the ipsilateral side but the messages from one ear are not strictly isolated to the contralateral hemisphere.
In this case the remaining eye would still send information from the left visual field to the right hemisphere, and information from the right visual field to the left hemisphere.
ok it's nice and all that the RH can realise it's holding a key, but the command you give the patient is only processed in the LH(what you've stated at the beginning at the vid), which is severed from the RH so what the hell??
Great question. Speaking is mostly controlled by the left hemisphere but the right hemisphere is capable of some language processing and can understand simple instructions.
srinivas anurag If the right hand had held the key or if the left hemisphere had seen the key (presented on the right visual field) then the person would be able to draw it correctly with the right hand. If the left hemisphere had received other information, however, the person would draw (with the right hand) whatever the left hemisphere had seen or felt.
That's a great question and there doesn't yet seem to be a definitive answer. One early theory (proposed by Santiago Ramon y Cajal) was that it had to do with the fact that the visual system is inverted (right visual field ends up on the left side of the retina) but this explanation is incomplete. More recent theories are that this cross-wiring (or decussation) resulted from a vertebrate ancestor turning on its back without rotating the brain (known as somatic twist theory) or that it results from two 90 degree turns that occur during embryo development (axial twist theory). These theories focus on how it may have occurred rather than potential benefits though it has also been proposed that crossing over could help to reduce wiring errors.
I read that split-brain surgery (severing the corpus callosum) is used as a last resort in patients with severe epilepsy. I am wondering if cannabis therapy is used a as treatment option for these people before resorting to the surgery. One would hope so. Healthcare in the West is so aggressive and in the wrong way in many cases (particularly with the treatment of mental "disorders" and "illness". Further, it takes so long for research to prove what should be obvious. The powers that be would be well advised to do a comprehensive history lesson into the demonisation of "drugs" which started early last century. We have a lot of catching up and rectifying to do in the West. I think coronavirus is a tidy reminder to us to reconsider what is appropriate in life and follow through with action accordingly, using the resources and connections one already has.
You're right that many drugs have been demonized in the past and now there have been some changes looking into how some psychoactive drugs might have therapeutic uses. Thanks for commenting!
I found out only a few months ago that I don’t have a Corpus Callosum. I am 48 now. I am also near sighted and far sighted and it can’t be corrected because my eyes work independent of each other. There is a question there but I can’t quite think of it. Great video.
Wow, that's quite interesting, thanks for commenting!
Why not two different lenses? Or differing laser eye surgery?
I really found myself thinking I am developing scholarly humour when giggling at your comment: "Wow, I've looked at a lot of faces today, my right hemisphere sure is tired" haha. Thank you so much for your clear and concise video, I have subscribed and can't wait to watch more!
How blessed are we as modern psych students to have youtube to help us learn in ways that suit us better than our studies. Cheers.
Glad you enjoyed it, thanks for commenting and let me know if you have any questions!
Clearly explained thank you! This topic was on my practice full-length mcat and I was totally clueless, but now it makes sense! :)
Kamala I'm glad it helped, thanks for watching!
You explained this better than my professor, thank you so much!
I'm glad I could help, thanks for commenting!
This channel is gold! Thank you so much for posting such quality contents!
You're welcome, thanks for commenting!
isn't he a decent good-looking guy? Thanks for the video. Helped a lot
Haha, thanks, glad it was helpful!
yea i noticed as well. btw the video was very informative thx
Thank you so much! This makes more sense than reading it in my textbook!
You're welcome!
About to take my psych exam and this is what I was mostly confused about! I think I got it now! Thank you so much
You're welcome, best of luck on your exam!
PsychExamReview aw thank you! I ended up getting a 95%, only missing 2 questions. I’m very happy about it!
@@CatnipMed That's great, keep up the good work!
Thank you! This video really helped me with preparing for my neuro final!
You're welcome, glad to hear that!
@Nadodi Mannan Girl why does this sound like Schizophrenia and less like a spilt brain thing
I was born missing my corpus collosum.
wow,i now enjoy psychology and its all because of you.Thank you so much
You're welcome, glad to hear you're enjoying it!
Thank you, this was clearly explained and so helpful!
You're welcome!
Your diagram was amazing actually. Kudos, good sir!
I wonder if a person with a split brain, is really two separate entities, but because they perceive the same information most of the time, that it rarely effects them.
You can go further and ask if that's true without the split too
I had this surgery, partially separated, not fully separated. Had trouble feeling one side of my body after the surgery and the disconnection syndrome absolutely sucked.
Perfectly explained I actually get it now thank you!
Glad to hear that!
No, he split the Nobel Prize because he shared it with his left brain
Not me procrastinating on my real psychology homework by exploring TH-cam’s suggestions right now
Hope you manage to get your work done but watching educational videos probably isn't the worst way to procrastinate
oh woww, I actually understood!
Great!
I think i'm going to pass my exams because of your vids, thank you so much!
I hope you do better than passing, best of luck!
I suffer from Atonic "drop" seizures almost daily and are very dangerous, not the falling but what you fall on or into. I've suffered from multiple broken noses, fingers, lost about 12 teeth before just getting a partial denture. 2nd degree burns on my face, road rash, and countless concussions and stiches from falling like a sack of potatoes. I had never heard of this operation until 2 days ago. The side effects are kind of scary but falling on a curb just right and breaking my neck also scares me. I still haven't decided the lesser of two evils.
Jeremy, did you end up doing this procedure? My daughter's epilepsy team is suggesting it for her. She also has drop attacks several times a day and is always showing some sort of bruise/cut/scrape/burn on her face at a given time. She is only 5.
Wow, I am so glad for you to find out about this so you can consider your options.
3:30 Are you completely sure about this example of the left brain specialization on language production given motor/tactile input? I thought the original study only showed that it works this way only when the input in visual. Motor input -> comprehension -> language output vs. visual input -> comprehension -> language output could technically be two separate pathways.
This tactile input example is based on Roger Sperry's early work with split-brain patients in which he tested both visual and tactile presentations. Here's a somewhat lengthy quote from Sperry (1968) describing these tactile tasks:
"A similar separation in mental awareness is evident in tests that deal with stereognostic or other somesthetic discriminations made by the right
and left hands, which are projected separately to the left and right hemispheres, respectively. Objects put in the right hand for identification by touch are readily described or named in speech or writing, whereas, if the same objects are placed in the left hand, the subject can only make wild guesses and may often seem unaware that anything at all is present.
As with vision in the left field,
however, good perception, comprehension, and memory can be demonstrated for these objects in the left hand when the tests are so designed that the subject can express himself through nonverbal responses. For example, if one of these objects which the subject tells you he cannot feel or does not recognize is taken from the left hand and placed in a grab bag or scrambled among a dozen other test items, the subject is then able to search out and retrieve the initial object even after a delay of several minutes is deliberately interposed."
Hopefully this helps address your question, you can find the original paper by Sperry here (above paragraphs on page 726 / page 4 of the pdf): sci-hub.st/10.1037/h0026839
I think depth perception from stereo vision is a more important advantage of the standard wiring than redundancy for loss of an eye.
Yes, good point, I would certainly agree that the wiring is really for binocular depth perception, not redundancy for losing an eye. But imagining losing an eye and still having information sent to both hemispheres can make the concept that vision is split by visual field rather than by eye easier to remember. Thanks for commenting!
So both hemispheres still connected by midbrain, right? So maybe this why he can hear just fine and doesn't notice much change.
I have some questions on this topic and hope you know the answer.
Are there any known cases, in which the right side of the brain begins to develop a better processing of speach in order to communicate?
How fast can the left side solve complex problems without the other half?
Was there ever an attempt to create a new connection between the brain halfes of a person born without an Corpus Callosum?
Are there any scans indicating weird behavior in the right half of the brain, since it is no longer able to express itself/influence its surrounding?
I'm so curious of these after reading your comment!
So many comments and no one is mentioning how hot this guy is 😹
i have some subtle symptoms of SBS but i recently got an MRI and i have a corpus collasum so i really donno what i have😞
Thanks for the video very interested and informative
You're welcome!
So when the left hemisphere makes up that story about the key, does the person's consciousness seem to sincerely believe what they're saying? Because they obviously cannot draw from memory. Is it more like the concocted event of the key used as a screwdriver is more of a hunch?
This is a good question that I don't really have a full answer to. The general explanation seems to be that the left hemisphere is good at generating explanations for behavior, but the person's belief or doubt in that explanation may be difficult to assess. What we even mean by the "person" may be challenging; the right hemisphere would certainly disagree if it could, but can the left hemisphere doubt its own explanations?
I'm not sure what you mean when saying they can't draw from memory though. In my example it's possible that he really had used a key as a screwdriver recently and remembered that, but this still doesn't make it the reason that the left hand drew a key (it drew a key because the right hemisphere saw a key). The left hemisphere attempts to generate a plausible explanation for this event and it may be based in accurate memories, but it's not the real reason, because the experiment design means the left hemisphere can't know the real reason that he drew a key (or whatever other stimulus).
The same concept of the left hemisphere generating explanations may be true for non-split-brain people in everyday life too. If someone were to suddenly quiz you on your daily behaviors, you might find yourself coming up with plausible explanations that might not really be accurate. If I were to ask you why you chose a particular menu item or why you chose to stand up from the couch at a particular moment, you might be able to come up with a reasonable justification but that doesn't necessarily mean it was the real reason for the behavior. But it might be very tough to assess how much you sincerely believe those explanations that you generate.
I think this leads us to larger questions about the challenges of understanding consciousness that I can't fully address 😅 Thanks for commenting!
If a person is born without the corpus callosum (Agenesis of the Corpus Callosum), do they exhibit the same inability to identify an object that is placed in their left hand or does the brain learn to compensate as they grow up? Is severing the corpus callosum in an adult different than a baby being born without it?
I don't think that this situation usually occurs for those with agenesis of the corpus callosum but there is a lot of variation between individuals and differences in the degree of connection between the hemispheres. They can usually transfer some information between hemispheres but this is impaired and often there are problems with coordination.
The early split brain studies by Roger Sperry and Michael Gazzaniga demonstrating hemispheric specialization used participants who had undergone surgery to sever the corpus callosum. Agenesis will influence brain development and may cause some tasks to be more distributed across the hemispheres, which won't have occurred in those who have the surgery later in life.
For example, savant Kim Peek (who had agenesis of the corpus callosum) developed language processing in both hemispheres, while someone who had the CC severed in adulthood would likely only have language processing in the left hemisphere.
I may have some ideas that could explain most of the things in this video related to the duality of all existing things and more specifically, the 2 halves of the brain. My theories seem to also correlate and explain loads of things related to religion and spiritual practices, dreams, REM-sleep and much, much more. If you read this and are like me seeking answers please contact me as I am not sure where or how to describe and debate all of this.
This phenomenon probably explains things like dreaming, REM-sleep and many religious practices and rituals not to mention subconsciousness (left)/ and consciousness (right) itself. Why the serious ** is not more energy put into this??!!?!?! It is probably the key to all these questions and more. I also speculate it may even be related to the key of dealing with cancer.
Some examples would be the father, the son and the holy spirit (Brain 1, brain 2 and both together).
It is the central concept of the importance of balance and yin and yang, the third eye and many many more things-
I mean just think about this. If you are watching something such as this video or reading a book, you are not directly absorbing the information but actually explaining to yourself in a manner that you can understand.
How else can you argue with yourself? Wanting different things at the same time and so on?
I also theorize that one part of the brain is responsible for input e.g. the inner world/emotion/perception whilst the other for output or action.
We even know that the first multicellular organism was composed of an outer cell that was in charge of survival and finding raw material whilst the inner organism was responsible for breaking down the raw material into nutrients.
It is so very obvious and somewhat easy to understand and for me, almost absolutely proven by split brain experiments yet it seems that every single person on earth just takes these findings at face value, are a little bit disturbed by the notion of being "2" beings and move on to other things.
It is almost beyond belief that this has seemingly never been discussed more indepth.
If you find this resonates with you and you wish to discuss this, please contact me !
Great video! I have a question - why can't split brain patients move their eyes separately (like a chameleon)? Or was their optic chiasm not cut and the eyes are somehow synchronized based on the opposite visual field?
Great question! The oculomotor nerve controls most eye movements and connects both eyes to the midbrain. This is not severed in these patients, so they don't have changes in their eye movements. Thanks for commenting!
What if the corpus is absent, speech is severely impaired and right lazy eye? Are those areas all connected? I'm disappointed I'm just learning this now. My sons favorite catchphrase for the last years has been "I don't know" and I'm learning it's related to his corpus callosum. His entire life he's faced stern disbelief in his apparent laziness towards daily tasks, by family, educators and strangers. Even his parents. Is this possible? To be skilled in something and not in others? I appreciate your input.
It might be possible that those are related but I can't really say. I'm not a doctor or neurologist; even if I knew more specific details I still wouldn't be qualified to offer any sort of opinion or medical advice. My only (non-medical) advice is to try to ask questions and learn as much as you can from the doctors or specialists you talk to while recognizing that the brain is incredibly complex and they may not always be able to provide clear answers or understand exactly how things are related. Sorry I can't offer more specific help and thanks for commenting!
So if a person were asked to draw what they saw with their right hand, according to the example you gave with the screwdriver on the right side and the keys on the left side, that person would be able to draw the keys only? I'm a bit confused.
If the screwdriver is seen in the right visual field then it will be processed in the left hemisphere, which then controls the right hand. So using the right hand, the patient would draw the screwdriver.
In this case, since the information is in the left hemisphere, the patient could also say the word "screwdriver" and then both hemispheres would know and then it could be drawn with either hand. This can't be done for information in the right hemisphere though, because the right hemisphere isn't able to produce speech.
@@PsychExamReview Thank you for the prompt response. I understand now!
@@nathalineg9491 I'm glad I could help, let me know if you have other questions!
@@PsychExamReview so both hemisphere hear what he says? how loud he should say it?
great topic thanks
I am teaching a little girl that had a split brain surgery due to seizures. We were told that her left brain works.
How does this affect her emotional behavior?
Excellent....one more subscriber...thanks!
Good to know
In the experiment of the key and the screwdriver, why doesn't the right hemisphere try to communicate to the left hemisphere the correct information, so that the left hemisphere can answer the question "why did you draw a key" without having to invent a story?
You are aware of being a "split brain", so why doesn't the right hemisphere try to communicate with the left hemisphere through other means, like using the left hand to write down the reason he previously draw the key.
Probably it is a silly question. Sorry for that, but I'm curious
It's not a silly question, I think it's a great one that points out an interesting aspect of these studies. When asked, obviously the question goes to both hemispheres for the split-brain patient so we should wonder why only the left attempts an answer (by speaking) while the right doesn't immediately tell the left hand to start drawing or trying to communicate in some way unless instructed. I don't have an answer, but this could be related to Alien Hand Syndrome, which involves losing control over a hand, usually the left hand (right hemisphere).
As for the awareness of being a split-brain patient, this also raises some interesting questions about consciousness because while the person can know and remember this information on a conscious level, it's unclear if this affects other unconscious brain processes. A related question is whether a split-brain patient has two separate consciousnesses (one for each hemisphere) or not, and as far as I know, researchers are still divided on this point - pun intended :)
This video was very clear, but there is still one point that I'm really not getting.
With a split brain the two hemispheres are not able to communicate anymore. The only thing that is connecting the two is the optic chiasm.
So, the right hemisphere can recognize faces, but can't talk, how does the left hemisphere - who can talk but can't recognize faces - know this when going to their friends and family?
Is it because by looking around, the hemispheres transfer the information trough the optic chiasm?
Thanks!
You're right, in everyday life split-brain patients are able to move their eyes around and this allows them to send information to both visual fields and thus both hemispheres.
Right, because they travel for some part trough both hemispheres ofcourse. Thanks! This video helped a lot. Will definitely look at more of your videos.
what about movement of his face and mouth. is it left hemisphere? if he feels sides of his head by different hemisphere he may use his tongue to send signals from one to another just touching his mouth differently from inside.
what about emotions? are they shared? he may use emotions to send signals from one to other.
so left may know what right hand holding by guessing and answering as yes/no. yes happy, no sad. Or something like it. He may use mimics on his face for it. What about meditation?
I just figured he may use his butt cheeks to communicate :-) Left controls right butt cheek, right left butt cheek. So he may send signals this way. Maybe even Morse code lol ) But probably simple yes/no is enough.... Because right can't process language :-( Maybe it's possible to train it some basic language)
Have anyone tried asking left hemisphere personal questions? Is it self-conscious? Where can I find more info on the topic?
Hi Alexander, essentially any spoken responses coming from a split-brain patient are just coming from the left hemisphere since it controls speech. So the left hemisphere certainly seems to have a fairly fully-developed sense of self. The more difficult part is assessing the right hemisphere because communication using language is necessarily simplified. This makes it much harder to really know what's going on in the right hemisphere. Michael Gazzaniga is one of the leading researchers on split-brain patients so you might start with some of his work. Ian McGilchrist has a book on hemispheric specialization which I've heard good things about but haven't had a chance to read yet. Hope this helps!
As both hemispheres are connected to the spinal cord, and the spine has its own neurones, is the brain’s neuroplasticity capable of developing communication between both hemispheres in some fundamental way?
This kind of dramatic rewiring doesn't seem to be possible later in life. While the spinal cord does have connections to both hemispheres, there is specialization of these pathways, sending information from the body to only one hemisphere contralaterally and split-brain patients don't show new pathways developing to send information across hemispheres.
That said, neuroplasticity for these pathways may be possible very early in development and there are cases of young children undergoing hemispherectomy (surgical removal of one hemisphere) and having the remaining hemisphere take over some of the functions of the missing hemisphere.
I have a question, it seems that right brain doesn’t act unless prompted. For instance, when you ask the patient to point with the left hand the object he was holding. Could you get more insight into the right Brains “ consciousness” by asking a question and have the patient close his eyes write with his left hand. (Would be favorable if the patient was left handed) thanks
I wouldn't think of it as the right hemisphere not being active, it's processing information but it's limited in how it can communicate that processing. It can't speak so it appears silent while the left hemisphere can respond quickly to verbal prompts. As for writing, I'm not sure how well split-brain patients can write with the left hand since language processing is more limited. Generally I've seen pointing to simple responses with the left hand used, I'd have to look into attempts involving writing.
So what is the difference to lobotomy? I cant really find an answer online , i just dont get how we can view lobotomy as one of the darkest times in medicine ever and then do that.
I just thougt we were over cutting up peoples brains without exactly knowing what it does.
Lobotomies were far less precise and made many patients worse off. More modern types of psychosurgery are very rare and are only used a last resort when symptoms are severe and other approaches have failed.
So if an object is shown in the left visual field, the right hemisphere cannot say what it is it saw, but if it saw a face or objects making up a facial pattern from the left visual field, then the right hemisphere can speak and say what it saw? If the left hemisphere specializes in speech and the right hemisphere cannot say specific objects, why can it speak up and say it saw a face? Is it just the way the brain works because the right hemisphere specifically specializes in faces? If the right hemisphere is more visual, why can it say it saw a face but not an object like a key? Love the video, it was very helpful!
The right hemisphere isn't able to control speech, but it has some language processing and the left hand (controlled by the right hemisphere) can indicate responses by pointing. So for something like recognizing a face, the right hemisphere can be shown an image and then be given a choice of what was seen and use the left hand to point to one of the responses. So a face made of books could be shown, then the patient would point to either "face" or "books". The right hemisphere (left hand) will point to "face" while the left hemisphere (right hand) would only identify books because it lacks the ability to recognize the overall face pattern. You can see a demonstration of this with a split-brain patient here: th-cam.com/video/lfGwsAdS9Dc/w-d-xo.html Hope this helps!
PsychExamReview thanks!
The fact that the left hemisphere is good at confabulating, may not be a trivial point. If someone doesn’t have the ideal levels of cross referencing, or is for some reason overly investing in their narration creation modules (on the left) then this may be a deeper level to the description of delusion or mania?
I should clarify that hemispheric specializations aren't trivial when it comes to figuring out how the brain processes information. There's research on activity levels by hemisphere in depression and other disorders that may improve our understanding and perhaps eventually improve treatment options. What I find trivial is popular books and articles encouraging people to do things like "work their right hemisphere" to improve creativity rather than just telling them to "practice tasks requiring creativity".
I don't see it as particularly useful to talk about being left-brained or right-brained and this is sometimes used to give an air of scientific credibility just by mentioning the brain. In everyday life we don't have conscious access to each hemisphere's activities and we can't choose to delegate tasks differently once we know about lateralization.
So while hemispheric specializations should certainly be investigated and taken seriously, popular books on becoming more left-brained or right-brained should not.
Thank you for the clarification. Yes it would be pseudo scientific to regard abilities/conditions as all reducible to this paradigm of hemisphere imbalance, and that one can improve things by focusing more on the ‘weaker hemisphere’
Thank you so much.....
Thanks that you said the side of brain is not important as we hear
So the person seems to live a pretty normal life but is that because the left hemisphere does all the communicating and it becomes dominant? Has there been any research on the emotional effects on the right side of the brain? Surely because it lacks the ability to communicate it has some emotional effects on it. Could there be a way to communicate non-verbally to the right side of the brain? Sorry if these questions are stupid, i am not majoring in psych so my knowledge is very limited on the topic, but it is so interesting!
The left hemisphere isn't necessarily dominant because the right hemisphere is still receiving and processing information. The right hemisphere just isn't able to control speech, so it can't talk about that information. Communication with the right hemisphere can take place by using the left hand to point at words (it has some language processing), draw pictures, etc. but this communication is certainly more limited. This makes it difficult to assess what's really going on in the right hemisphere, though the fact that the left hemisphere doesn't seem too bothered by the division suggests that the right might not be either.
I had the wrong patient's brain surgery when I was 17 years old, with absolutely no help at all, for either operations- and I have believed for a long time that they severed the two hemispheres of my brain, because I have a scar going along the middle of my brain, to at least the middle of my head, and another scar where I had the other operation. I have had severe problems with communicating on an emotional level. Not so much for simple situations, such as something like- "please pass the salt", for instance, but very important means of communicating, as I said, on an emotional level. I have had to live with my circumstances for over 30 years, now. I feel as if I was in a glass box, and people could see me, and I could see them, but there was definitely something keeping me from being able to connect- as I said- on an emotional level. Any suggestions that might be able to help me? Thank you.
I'm sorry to hear about your situation. Unfortunately I don't have the expertise to provide specific suggestions and can only suggest you contact medical professionals who might be able to provide more help, thanks for sharing your story here!
I hope your family sued that hospital for malpractice.
@@tiffanyrichardson6698 My family and were never able to find a way to sue. In South Africa- the lawyers and doctors are on the same side. I didn't even get any help with aftercare for the surgeries that I had. I have been in a very bad situation for over 32 years (or it will be 32 years on September 1St). I have also been forced to live an absolutely separated life from my sons- BrianG (nearly 14 years old) and Gregory- (nearly 10 years old- both this month- in a matter of days) who were 5 years old (Brian) and Gregory was 15 months old when they were literally ripped out of my arms and my life. What is so much worse- is that their father was- and is very emotionally and psychologically abusive and how he has treated us (my sons and I by permanently keeping us separated- for what will be 9 years in December). This is excruciating for me beyond words. And their father wants my eldest son vaccinated for the terrible vaccine- which is- or may as well be literal extermination. Please keep my sons in your prayers. I see them- at the most- twice per week- four hours per week- and it is terrible to be forced to live this way. My current husband, Jesse, (who treats me SO much better than their father did for the 10 years we were married)- and I- have tried- with no success- Jesse and I did try to get legal help- and I have tried to get some help with disability- but there is red tape (mostly that the drs. who performed my surgeries in South Africa- destroyed my evidence which shows that the first MRI was not the scan that belonged to me. It is over (or practically 32 years ago- within literal days)- of it being 32 years ago that I had the surgeries. But I still have very bad side effects which makes it nearly impossible for me to get a regular job. I was 17 years old at the time and will be 50 years old next year. This is literally my entire life that my life has been very badly affected. But I miss my sons so much- and it hurts beyond being able to put it to words of how my sons and I have been separated. Please keep them (and us)- and my mom, Claudette in your prayers. My dad passed away just before the PlanDemic started. My mom still lives in South Africa. I have not seen my mom (or my dad- while he was still alive)- for what will be 10 years ago- on August 17 Th. They came for their last visit on the day my youngest son, Gregory- was born. Sorry this is so long, but thank you for your response. May you and your family be blessed. We are living in extra-ordinary times- Biblical- even. It won't be long, now- before Yahshua (Jesus) returns. Help us all if He doesn't. But how can life go on this way for very long?
One thing bugs me. When the right hemisphere is the one that recognizes faces and the left the one that does the speech, how does the right hemisphere tells the left hemisphere what person you're talking to? How could ... in your example ... the person tell you, that he or she saw a face, if the speaking hemisphere can't do that.
The section about this phenomena in Sam Harris' book 'Waking up' fascinated me, so I came here looking for more info. Thank you for an excellent video. I wonder if you have any comments on what this tells us about the nature of consciousness or the self? It feels like it somewhat tramples on notions of the self as a unitary actor in a way that is both intriguing and confusing.
Phillip Wareham I haven't read Waking Up but I'll check it out. As for the nature of consciousness, you're right that it raises the questions of how and why consciousness feels unitary despite containing multiple systems which appear to operate independently. These split brain studies also introduce the question of how much of your sense of self might just be post-hoc explanations of behavior coming from the left hemisphere. Perhaps this can serve as a reminder to think of ourselves as collections of motivations and processes (conscious and unconscious) that somehow converge to create a sense of self that feels unified and in control. One might argue that unity and control are just an illusion, but it seems to me to be a particularly useful illusion and far superior to the chaos of fragmented consciousnesses.
huh? but in the example with Arcimboldo, how can the patient say "I saw a face" if the right hemisphere doesn't have the language center? he knows what it is but can't say it, or am I wrong? or if its a general term like "face" he can say it?
The patient can point to words on the screen (with the left hand) to indicate whether he saw a face or books (or whatever objects the face was made of). The right hemisphere has some basic language processing and can recognize words.
@@PsychExamReview thank you very much!
My 15 year old daughter is a high functioning PACC only child. Our daughter only has 20% of her CC in the frontal lobe. Are you saying that if we were to sever this 20% our daughter would have a better chance at a normal life??
Laura Wright Partial (or complete) agenesis of the corpus callosum is different from callosectomy in terms of how the brain has developed over time. I described split-brain patients as appearing "normal" in that one probably couldn't tell they had undergone the procedure but there are still subtle linguistic and social effects of this disconnection (which may also be similar to PACC or ACC). I should also emphasize that I'm not a doctor or neurologist and nothing I discuss in my videos should be taken as medical advice. You might like to read this article in which people with agenesis of the CC discuss their diagnoses:blogs.scientificamerican.com/observations/patients-reflect-on-life-with-a-common-brain-malformation/ Thanks for watching!
PsychExamReview - Thank you!
What if we blindfold the person and ask him to choose with the right hand among other objects what he saw.....what would he pick???
As long as the left hemisphere has received the information somehow (if held by right hand previously) then the person would be able to select the object with the right hand (which is controlled by the left hemisphere).
@@PsychExamReview thank you!!!
This video is very helpful though o have a question why do we understand what we are seeing by right brain when we don’t have a functional wernickes area in that side
This is a good question and it seems that the right hemisphere does have some basic language processing, even though the left hemisphere is generally where most language processing happens (for most people).
PsychExamReview Ok but only for visual signals we have this language processing right ? Cause we are not able to understand the auditory signals being transferred to our right brain . And does it have to do something with the angular gyrus on that side cause some visual processing do occur there ? I came up with this explanation could u please confirm
@@Doctor_t.f.m As far as I know, split-brain patients must be able to understand some auditory signals in the right hemisphere because the right hemisphere can follow instructions (such as being asked to draw something with the left hand) but I don't know the limits of that processing or whether more complex instructions or questions can be understood.
As for the role of the angular gyrus, it seems reasonable it could be involved in recognizing written words and it has been suggested that the right angular gyrus plays a role in understanding spatial metaphors. So that might relate to some language processing abilities in split-brain patients but I haven't looked at specific research on this topic. So I don't know well-supported the metaphor idea is or how it might relate to other language processing in the right hemisphere. I simply don't know and can't really confirm.
PsychExamReview yes you are right about that instruction part but I saw it in GUyton and Hall Physiology and I was confused Like it says here “in a teenage boy with sectioned corpus callousum, only left brain can understand both written and spoken words , however right side of brain could understand the written words but not spoken words “. This got me confused that day
@@Doctor_t.f.mThat is a bit confusing, though it could be the case that there are some individual differences in lateralization of language processing that would mean that not all split-brain patients would be identical in their language abilities for each hemisphere.
I’m 45 and just found out I don’t have one. I found out from an MRI after a car accident.
Hey PsychExamReview, how does audio work with these type of people? For example, you ask both sides of the brain if the person is religious or not and they give opposite answers, how would this experiment work?
As far as I know auditory messages can't be isolated the way visual messages can be. This is because nerves from each ear are not strictly lateralized and there are connections to the opposite side (contralateral) as well as same side (ipsilateral) hemisphere.
@@PsychExamReview even if they cover the ear?
@@HondaS-fk1mi Yes, nerves from one ear go to the midbrain where there are connections leading to the cortex of both hemispheres. I believe there are more connections to the contralateral side than the ipsilateral side but the messages from one ear are not strictly isolated to the contralateral hemisphere.
What happens if the person has a split brain and are completely blind in one eye??
In this case the remaining eye would still send information from the left visual field to the right hemisphere, and information from the right visual field to the left hemisphere.
ok it's nice and all that the RH can realise it's holding a key, but the command you give the patient is only processed in the LH(what you've stated at the beginning at the vid), which is severed from the RH so what the hell??
Great question. Speaking is mostly controlled by the left hemisphere but the right hemisphere is capable of some language processing and can understand simple instructions.
what if he draws with his right hand instead of his left hand....will he draw key or screwdriver..?
srinivas anurag If the right hand had held the key or if the left hemisphere had seen the key (presented on the right visual field) then the person would be able to draw it correctly with the right hand. If the left hemisphere had received other information, however, the person would draw (with the right hand) whatever the left hemisphere had seen or felt.
@@PsychExamReview but what if he looks with both eyes and corrects to match to what he saw at right side.
what is the benefit of contralateral brain control?
That's a great question and there doesn't yet seem to be a definitive answer. One early theory (proposed by Santiago Ramon y Cajal) was that it had to do with the fact that the visual system is inverted (right visual field ends up on the left side of the retina) but this explanation is incomplete. More recent theories are that this cross-wiring (or decussation) resulted from a vertebrate ancestor turning on its back without rotating the brain (known as somatic twist theory) or that it results from two 90 degree turns that occur during embryo development (axial twist theory). These theories focus on how it may have occurred rather than potential benefits though it has also been proposed that crossing over could help to reduce wiring errors.
why am i watching this at 3 am
Fuck. Mind blowing!
I read that split-brain surgery (severing the corpus callosum) is used as a last resort in patients with severe epilepsy. I am wondering if cannabis therapy is used a as treatment option for these people before resorting to the surgery. One would hope so. Healthcare in the West is so aggressive and in the wrong way in many cases (particularly with the treatment of mental "disorders" and "illness". Further, it takes so long for research to prove what should be obvious. The powers that be would be well advised to do a comprehensive history lesson into the demonisation of "drugs" which started early last century. We have a lot of catching up and rectifying to do in the West. I think coronavirus is a tidy reminder to us to reconsider what is appropriate in life and follow through with action accordingly, using the resources and connections one already has.
You're right that many drugs have been demonized in the past and now there have been some changes looking into how some psychoactive drugs might have therapeutic uses. Thanks for commenting!
Read Phantoms in the Brain: Probing the Mysteries of the Human Mind.
Excellent recommendation!
Sound is bad.
Comment Awards?
What about genitals? :-) What hemisphere feels it?