Psychology Addict # 54 | Metacognition, Neuroplasticity & PR’s Incredible Brain.

in #psychology2 years ago (edited)

PR is a real person who, together with another 56 individuals, took part in the experimental study conducted by Lemaitre et. al (2018) ref..

Brain FI - BS.png

PR is a married 43 year-old man, who works as a butcher in a supermarket, and has two-children. In 2004, PR had a generalized seizure. His MRI showed that his left frontal cortex had been invaded by a tumour (a DLGG – a diffuse low grade glioma). Part of PR’s left prefrontal cortex was then removed.

The prefrontal cortex is the most anterior part of the brain. This is a brain region which, over the course of our species’ evolution, underwent changes that has made possible for us, humans, to develop abilities which granted us a unique place in the animal kingdom. High-order cognitive abilities, like critical thinking, is an example of this. But it doesn’t stop here. Because we, humans, have also developed the ability of “knowing that we know”, or of “thinking about our own thoughts”. Something which in the neuropsychological world is known as metacognition. It has been thought that this function critically depends on both functional and structural properties of the pre-frontal cortex and, above all, its most anterior part: the Brodmann area 10 (BA10).

Four years after his surgery, in order to prevent the glioma invading deeper brain structures PR underwent chemotherapy for 18 months. Unfortunately, the glioma still progressed into the left pre-frontal cortex, and in 2010 a second procedure was performed. PR’s entire pre-frontal cortex was removed under “wide-awake” conditions.

Functional magnetic resonance imaging (fMRI) studies have demonstrated an association between the anterior pre-frontal cortex activity and metacognition performance. Beyond “knowing about knowing” metacognition is also at the basis of self-awareness. This is also a function that enables the reorganization of mental processes and allows us to strategize and plan. Abilities which accuracy decreases following damage to the left or right pre-frontal cortex, as demonstrated by early neuropsychological studies ref..

But, back to PR. In 2014 the merciless glioma infiltrated into his brain’s right hemisphere, consequently leading to yet another surgical procedure. In the end, overall, PR’s surgeries included the complete removal of his left pre-frontal cortex, and the total removal or his left and right BA10. According to Lemaitre and his colleagues (p. 49), PR is:

“probably the only person in the world to have undergone very extensive bilateral pre-frontal resection”

Now, what do you think it happened to PR’s metacognition abilities?

Neuroplasticity Comes to Rescue.

Neuroplasticity - BS.jpg

Human beings are equipped with the incredible ability to adjust to novel situations, including those that emerge from biological processes (e.g. brain injury caused by a stroke). In such cases, neuroplasticity is a mechanism that equips, and aid individuals to do so. As it enables the brain to redistribute and remap cognitive functions in response to brain damage.

Research conducted on aphasia patients provides strong evidence for this. Aphasia is a language impairment that results from lesion to the brain. It is typically seen in people who have suffered a stroke. This impairment is often overcome by individuals as a result of the brain’s dynamic nature, the capacity it has to modify its connections and restructure itself.

In aphasia cases this is generally explained by a mechanism whereby the right hemisphere of the brain, subsequent to a lesion to the left hemisphere, appears to take charge of, or play a greater part in cognitive functions involved in language processing that were previously executed by the current lesioned region ref.. This mechanism consequently allows people to gradually recover from the impairments brought by the damages caused by the stroke.

Take Ginger’s case, for instance. Ginger is a 47 year-old business owner who suffered a stroke which damaged part of her left hemisphere (the Broca’s area), the brain hemisphere strongly responsible for language functions such as understanding and speaking. Still, subsequent to a 12-week part-time treatment, Ginger’s degree of plasticity allowed her to progress from being unable to write and understand numbers and emails to making phone calls, writing and reading invoices ref.. Good job Ginger! 😊

How is this possible?

Thanks to the Remaining Functional Network

BA10 - BS.jpg

It has been proposed that this compensatory ability of the brain happens thanks to the functional networks that are still up and about in the adjacent areas. Furthermore, recent research suggests that plasticity in cortical regions is rather high ref..

Things look promising for PR 😊

Lemaitre and his colleagues pointed out that following each operation PR was able to return to his work and his social life. Still, the main purpose of their experimental study was to look into whether metacognition could be maintained after the removal of the BA10. You see, previous neuropsychological studies indicated that such procedures impair metacognition.

But do they really?

To check this out, a two-part task was then set for:

➡ PR
➡ 9 patients who had their right prefrontal cortex, including the BA10, removed.
➡ 9 patients who had part of their right prefrontal cortex removed, not including the BA10.
➡ 38 healthy individuals.

The task:

The first part consisted in asking participants whether a certain darkened pattern (a Gabor patch) had appeared in the first or the second displayed image. They were presented with a succession of pairs of image that flicked very quickly. This was to test perceptual discrimination. Next, the real business! As part two was all about looking into the participants’ metacognition abilities. For example, after a participant said the darkened patterned appeared in, let’s say, the second display they were asked: “on a scale from 1 (very low confidence) to 6 (very high confidence) how certain are you about this answer?” –Every participant took part in 350 trials.

PR got 70.86% of task 1’s answers correct (that’s my man!). Moreover, in neither task, did PR’s answers differ significantly from those given by the other participants (including the healthy ones).

As I have been repeatedly pointing out the BA10 plays a crucial role in the most complex human abilities (e.g. self-assessment), and for this reason it is believed to be at the very top of the hierarchical organization of the pre-frontal cortex. Therefore, such sophisticated functions have been said to be directly and continuously linked to both the BA10 and the other cortical structures discussed here.

Through experimental evidence Lemaitre and his colleagues demonstrated this is not quite so. And that, subsequent to injury, brain plasticity go as far as enabling the remapping and redistribution of metacognitive functions.

But, not all is a walk in the park. PR was left with some difficulty with finding words during speech. What is more, PR as well as the other patients, were able to present such incredible metacognitive preservation because of the nature of their brain injury. In previous studies (for example, see Fleming et.al (2014)) patients whose metacognition was impaired had underwent similar surgical procedures due to medication-resistant epilepsy, or other non-identified types of tumour. See, the slow-growth of low-grade gliomas allows the brain to achieve remarkable levels of plasticity. In these cases, the speed with which the tumour progresses is an important factor in determining how efficiently cognitive and metacognitive functions will be reorganised and remapped.


Image Source: 1, 2, 3

Reference List:

The Aphasia Center

Fleming, S. M., Ryu, J., Golfinos, J. G., & Blackmon, K. E. (2014). Domain-specific impairment in metacognitive accuracy following anterior prefrontal lesions. Brain, 137 (Pt 10), 2811–2822.

Lemaitre, A., Herbet, G., Duffau, H. and Lafargue., G. (2018) Preserved metacognitive ability despite unilateral or bilateral anterior prefrontal resection. Brain and cognition. Vol. 120, No. C, pp. 48-57.

Turkeltaub, Peter E. ; Coslett, H. Branch ; Thomas, Amy L. ; Faseyitan, Olufunsho ; Benson, Jennifer ; Norise, Catherine ; Hamilton, Roy H. (2012), The right hemisphere is not unitary in its role in aphasia recovery. Cortex, Vol.48, No. 9, pp.1179-1186.



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My Dear Reader,

Thank you for taking some of your time to read my post. I do hope you’ve found it interesting :)

All the best to you all,

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That's a brilliant analysis of the papers from 2014 and the current one. This makes me wonder what was the exact reason behind the restoration of metacognition in one study Vs other. I couldn't say if they have a big difference in their methods. However, like you said they had brain lesions for different reasons. This curiosity is bugging me a lot.

Anyhow, this also reminded me of phantom blindness mentioned by VS Ramachandran in his book "phantoms in the brain". In that case, victims who have suffered some sort of brain injury can see, but they can't know that they can see. For instance, they can in quick reflex pick and pass the largest or smallest box on the table but can't know that they can see the box. It's been a long time since I read that book, but I think, in this case, the visual cognition for knowing that they saw an object was in a different region of the brain (I will go home and confirm this later). So there is a likelihood that different kind of metacognition processes are distributed across the brain?

Also, I remember reading this article long ago. But he seems to be doing ok in life. It seems as if the neural networks in another place can learn to do the same tasks, as your post suggests. However, the question that's bugging me when it does and when it does not? Anyway, I will go and read more on the topic. Thanks for sharing this wonderful post.

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My Dear Abigail:
A humdinger this time!! I love the science, the details. No way you put us (me) to sleep. My mind was making associations as I read. The last bit I found most fascinating, and informative: It was the nature of PR's brain injury that allowed neuroplasticity to kick in as well as it did. The pace at which damage occurred gave the brain time to adjust. Sudden, traumatic injuries, like stroke, do not give the brain that luxury usually.

We all know someone, don't we, who has in some way suffered an injury to the brain?
My brother suffered the more sudden, traumatic sort. He had a devastating attack of autoimmune encephalitis when he was in early 70s. Because of a delay in diagnosis, he lost specific functions--short-term memory and spatial orientation chief among them. Vocabulary and thought processing remain intact--he does very well on intelligence tests. Your explanation for why his brain has not compensated as we hoped it might (his loss occurred over a very short span of time) helps me to understand the persisting difficulty.

Reference to metacognition also sent me down a sort of rabbit hole looking up studies on autism--theory of mind, self-awareness, etc. An area of speculation not exactly related to your subject...but then tangents are inevitable when the material is rich. Such an open field. So much research to be done. So many people, families affected. To start with, there seems to be a need for a better understanding of metacognition and self-awareness.

Thank you for this informative and stimulating piece.

With respect and appreciation,
Love from New York,
AG

Weee! 😃 I'm so happy with the positive feedback I'm receiving from this post. And, of course, yours @agmoore, means a lot to me! Everyone seems to have stayed awake 🎈:)

You brother did very well! The preservation of intelligence and vocabulary are so important for patients and their families. It can be so devastating for some people to lose the ability to communicate verbally, even if temporarily.

And yes! As always, you got it! The nature of the injury is a huge factor in how effective neuroplasticity will take place. But, in your brother's situation, his advanced age (in his early 70's) also contributed to the persisting limitations.

For example, Individuals who have hemispherectomies during childhood years (due to abrupt damage) have the ability to develop speech and comprehension of speech even if the left hemisphere is the one removed ref.. How remarkable? This is not quite the case for older individuals, though.

With much, much love and infinite gratitude,
Your Brazilian friend,
Abigail

That is by far an interesting study!

The human brain is so amazing. I am at the end not surprised that it manages to redistribute what needs to be redistributed elsewhere in it to make the human work.

Yeah. Very interesting indeed. The compensation and remapping of metacognition is gobsmaking!

Thank you very much for stopping by once again @lemouth.
I wish you & the family a relaxing Sunday, tomorrow.

:)

Thanks (reading this on Monday evening, as I was away on Sunday ;) ). I am today back at work ^^

Oh! I trust you had a nice holiday and are now ready to return to your activities! :)
Good night to the family. It’s bed time over here 😴😊

Another article from you!

As others already have pointed out, almost everyone can tell a story from family or friends about brain surgery.

When I was 12, my mother had a cerebral apoplexy in the garden. She was taken to hospital by emergency and had a very long operation on her brain, I think it was eight hours. I was not allowed to go into the intensive care unit. Later, when she was lying in the normal room and I saw her for the first time, her head was completely shaved and she talked nonsense. Strangely enough, I wasn't very scared, although my father told me in simple words that my mother could remain "stupid". She said very blunt things, ordered the keeper around and smeared combinations on her bread that I had never seen her eat before. All in all she seemed like a funny child who was amused by what the others were doing or not doing. At that time she was a completely different personality, at least that's how it seemed to me. I think the reason I didn't worry so much was that I didn't see her suffer. There were no signs of psychological or physical discomfort with her. It took her several weeks to be able to properly speak, walk and move again. I suppose she also lost some nerves, such as her sense of smell. Although not completely. At some point she was back to her old self and the episode went into the past and we never actually talked about it again. At that time she was 54 years old. The funny thing is, that I missed that kind of mother, as she seemed less earnest and strict. I guess the others from my family perceived all things differently but I truly was in awe with this change she went through in a positive way. Maybe I repressed my fear, though, who can tell? ;-)

I agree with you about the complexity of the brain and the fact that you can't divide the individual abilities into small drawers and shelves and only assign them to certain regions. That would be too easy. I can't even begin to imagine what it's like to do an operation as a brain surgeon. In the past, people would simply have died from a brain haemorrhage, for example. My ex-brother-in-law had a severe operation and the location was so unfavourable that he subsequently has a permanent facial paralysis. However, he has lost nothing of his mind and no meta-skills.

Quite moving to hear what your mum and your family went through when you were only a kid Erika. Particularly how you perceived your mum's "new", temporary self and even missed it afterwards :)

Thank you for sharing this moving account of your life here! It's much appreciated :*

Lots of kisses and tight hugs from warm Portugal! :)

Thank you, I was assuming you'd appreciate it. I wouldn't have thought of the family happenings if I hadn't read this blog entry from you. Gave me a chance to think a little of the past and what humans are capable of.

Kisses from rainy Hamburg!

While reading this, I remembered the story of the surgical procedure that was popularized by Dr. Ben Carson; Hemispherectomy, which involves removal of part of the cerebral hemisphere of the brain, and the person will still assume normal cognitive abilities (all thanks to the human brain's ability of neuroplasticity).

It is very amazing how the human body can re-configure itself to adapt to a particular situation - no wonder humans have adapted and survived so long through evolutionary "thicks and thins".

Amazing piece as usual, Abbey. Much love from Nigeria

no wonder humans have adapted and survived so long through evolutionary "thicks and thins".

Nicely put! The extent of our adaptation capacity never ceases to amaze me. We truly are remarkable beings :) I'm so glad you enjoyed reading this peace Sammi, as I was particularly fascinated by this study and PR's resilience!

Sending you bags of love all the way from Portugal :)

Thats very interesting. Its incredible what the human brain (or any organisms brain really) is capable of. Neuroplasticity is especially facinating. Its funny how specific regions of the brain have very specific functions normally, but that there are major exceptions to that rule in terms of neuroplasticity. Its like, this part of the brain does XY and Z, but if another part of the brain gets damaged then this part of the brain may compensate by doing any task that it needs to. Lol

I recall a finding from a neuropsychology class I took a while back where researchers found that individuals with vision impairments (blindness...etc) often had enlarged somatosensory regions in their brains. In some cases their visual cortext would also switch from processing visual data to processing other sensory data like touch or hearing or whatever. It would seem that the individuals brain compensated for a lack of vision by increasing the functioning of other brain regions dedicated to other senses.

I know that there were a whole brunch of cool findings like that, but unfortunately I cannot actually remember them enough to discuss them here hahaha :S
Anyway, great post!

Hey @leaky20 :D

I'm so pleased you found this post interesting! I found this study particularly fascinating and it took me a while to find a way (in my head) to write it in a manner that wouldn't send people straight to sleep 😂 What you said about the brain is spot on! Well, the days when it was believed that "this little area here is exclusively responsible for this function and that one for that, seem to be, thank God!, long gone :)

Interesting info you provided here about compensatory systems in blind individuals. It brought to mind a piece of research I came across a while back that points to the possibility of cortical blindness protecting people from developing schizophrenia. For reasons similar to the ones you highlighted here : early developmental neuroplasticity that compensates and/or enhances brain processes (e.g. sound perception and construction of subjective experiences), which often don't function well in individuals living with schizophrenia :)

Thank you @leaky20, for your constant, encouraging support.
You guys take care over there!

My word! This is definitely the most medically inclined post on steem since it's inception three years ago I can bet my life on this really. In earnest what I know is that sometimes we're stronger than our body. Sometimes the way our body fights some of the most deadliest of illnesses that plagues us is dynamically unique and sometimes it Marvels us.
My uncle had stroke and in the first three days he couldn't even form words and wasn't in control of his urinary tract. In short he couldn't understand or sense the urge to use the bathroom but my goodness he fought. After a physiotherapy session the doctor felt it was a miracle that's he's managing to pick up objects in just a few weeks
Like PR there I felt it's definitely incredible how we tend to be conquerors in trying so hard to fight and hold on to life.
Myself I'm going through a life long genetic disorder but somehow I'm thriving, working, making progress, it felt like I can't do this at a certain stage of my life. I'm sorry I'm going off board. This post is making me reminisce so many aspect of my life.
Beautifully written really, wow you don't just bring it any lesser

Oh @josediccus, this is such a wonderful comment. You have made such beautiful remarks here, especially when you said :

how we tend to be conquerors in trying so hard to fight and hold on to life

It truly reminded me of my father. He fought it till the very end. He was sick for 6 years, but he never, ever gave up. I am very proud of him for this, for his will to live :) I'm sharing this with you in return to you sharing your uncle's uplifting story as well as your own. I mean, you are a poet, a loving son (and all the other things I don't know about) all the while fighting a disorder.

It is simply inspiring @josediccus, to say the least!

Thank you for this incredible feedback!
Much love,
Abigail :)





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Thank you @steemstem 😊❤️

Very interesting article, Abigail :-)
Your post has really tied me to the screen.
It's amazing what our body is capable of. Also, the "self reprogramming" of our brain, where then other parts, learn to take over other tasks is amazing.
Thank you very much for bringing this to the STEEM chain :-)

Your post has really tied me to the screen.
😃 Thank you @astrophoto.kevin! For taking the time to read my work and leave such a lovely, encouraging comment! I was a bit dubious about this one. But it turned out to be a well-accepted post. Well, maybe, because of what you said: the amazing ability of our brain! It is fascinating for everyone :)

I wish you a wonderful night.
All the best,
Abigail :)

You're welcome, Abigail :-)
I don't quite understand your doubts. Wonderfully written and very revealing.
I would appreciate it to read more about it in the future :-)
I'm wishing you a wonderful day, full of energy :-)
Greetings

😊☀️



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Amezing blog on health and brain.

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