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My latest work, out now:
"Large-scale resculpting of cortical circuits in children after surgical resection"
with @mgranovetter @erezfreud1 @KastnerLab @_mpinsk Christina Patterson & Marlene Behrmann
https://www.nature.com/articles/s41598-020-78394-z
#AcademicTwitter #ECRChat @OpenAcademics
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"Large-scale resculpting of cortical circuits in children after surgical resection"
with @mgranovetter @erezfreud1 @KastnerLab @_mpinsk Christina Patterson & Marlene Behrmann
https://www.nature.com/articles/s41598-020-78394-z
#AcademicTwitter #ECRChat @OpenAcademics
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In this work, we studied functional connectivity and found widespread reorganization in the preserved contralesional hemisphere in children following a unilateral (meaning one side only) brain resection for the management of drug-resistant #Epilepsy
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First, I want to say that our work would not be possible w/o cooperation of the children & their families that participated in this study and other ongoing projects
With much help from @BrainRecoveryP
And for that, we thank you all!
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With much help from @BrainRecoveryP
And for that, we thank you all!
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Let's dive in:
We scanned 2 individuals who had complete removal of their entire left hemisphere and 7 more who had smaller, circumscribed resections in either hemisphere for management of seizures.
We also scanned age-matched controls, for comparison
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We scanned 2 individuals who had complete removal of their entire left hemisphere and 7 more who had smaller, circumscribed resections in either hemisphere for management of seizures.
We also scanned age-matched controls, for comparison
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From previous work in the lab, we know children do not show any problems in their higher-order #Vision (like recognizing faces or objects) even after the unilateral (meaning one side only) resection of the visual cortex
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We also know that they show brain responses in the preserved cortex that are comparable to their peers
Read about those studies:
@CellReports
https://www.sciencedirect.com/science/article/pii/S2211124718310416
And from the Journal of #Neuroscience
https://www.jneurosci.org/content/jneuro/39/32/6299.full.pdf
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Read about those studies:
@CellReports
https://www.sciencedirect.com/science/article/pii/S2211124718310416
And from the Journal of #Neuroscience
https://www.jneurosci.org/content/jneuro/39/32/6299.full.pdf
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My 1st question coming into this project was:
if the brain responses are normal (brain parts do what they're supposed to), does this mean the connections between different parts were also normal?
Or did the connections change to accommodate the removal of some brain tissue?
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if the brain responses are normal (brain parts do what they're supposed to), does this mean the connections between different parts were also normal?
Or did the connections change to accommodate the removal of some brain tissue?
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Here's an analogy:
If you have a two-lane road and one lane was blocked, traffic would increase on the remaining lane. How then would the remaining lane change in response? For example, does the lane need to become wider to accommodate all the cars?
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If you have a two-lane road and one lane was blocked, traffic would increase on the remaining lane. How then would the remaining lane change in response? For example, does the lane need to become wider to accommodate all the cars?
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Answer: we found that the white matter organization + microstructure in intact hemisphere was comparable between patients and controls (damage was limited to the white matter in the precise site of the surgery)
Read about this work @NeuroImage_EiC
https://www.sciencedirect.com/science/article/pii/S105381191930936X
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Read about this work @NeuroImage_EiC
https://www.sciencedirect.com/science/article/pii/S105381191930936X
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In terms of the 2-lane road analogy above: the remaining lane didn't (have to) become wider
A side note:
if the responses and white matter are normal, does that mean one hemisphere is enough?
@mgranovetter answers this question in his #PhD work:
https://www.biorxiv.org/content/10.1101/2020.11.06.371823v1?rss=1
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A side note:
if the responses and white matter are normal, does that mean one hemisphere is enough?
@mgranovetter answers this question in his #PhD work:
https://www.biorxiv.org/content/10.1101/2020.11.06.371823v1?rss=1
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Back to connections:
Why would we expect to see changes in functional connectivity given everything else has been normal so far?
In a typical brain, computations that serve as basis of cognition are carried out in the 2 hemispheres (we don't only use 10% of our brains)
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Why would we expect to see changes in functional connectivity given everything else has been normal so far?
In a typical brain, computations that serve as basis of cognition are carried out in the 2 hemispheres (we don't only use 10% of our brains)
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What happens then if you take away some or even as much as half of the brain?
This is where our study comes in.
We wanted to know how a brain with limited resources can still function optimally such that the children do not show obvious cognitive deficits.
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This is where our study comes in.
We wanted to know how a brain with limited resources can still function optimally such that the children do not show obvious cognitive deficits.
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What changes are we seeing in this new work @SciReports?
https://www.nature.com/articles/s41598-020-78394-z
We looked at positive and negative correlations (functional connectivity, FC).
First, we found that positive FC was comparable between patients and controls in the preserved hemisphere
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https://www.nature.com/articles/s41598-020-78394-z
We looked at positive and negative correlations (functional connectivity, FC).
First, we found that positive FC was comparable between patients and controls in the preserved hemisphere
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This means that brain #Networks that typically work together, still do work together!
This is consistent with previous results of normal brain responses.
But wait, there's more!
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This is consistent with previous results of normal brain responses.
But wait, there's more!
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We also found that these same regions showed atypical negative FC.
What does this mean?
We argued that the negative connections possibly "break down" the links between regions (when these regions are not engaged in a particular task) allowing new connections to form
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What does this mean?
We argued that the negative connections possibly "break down" the links between regions (when these regions are not engaged in a particular task) allowing new connections to form
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How are new connections formed?
Do regions that are close together work more closely, thus saving time and energy?
Or do regions "reach out" to farther areas, perhaps because the nearby regions are already "taken"?
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Do regions that are close together work more closely, thus saving time and energy?
Or do regions "reach out" to farther areas, perhaps because the nearby regions are already "taken"?
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We found that in the preserved hemisphere of the resected brain, whatever available resources are utilized, be they near or far.
That is, there is increased cooperation between all regions in the preserved hemisphere of the resected brain.
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That is, there is increased cooperation between all regions in the preserved hemisphere of the resected brain.
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Taken together, our results point to brain #Plasticity:
Widespread reorganization in the intact hemisphere and this reorganization possibly enables normal functions given the reduced cortical territory (in children with either small or large resections)
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Widespread reorganization in the intact hemisphere and this reorganization possibly enables normal functions given the reduced cortical territory (in children with either small or large resections)
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To wrap up, let's look at another analogy: trains & railroads
If a landslide occurred and blocked the railroad from A to B, this doesn't affect the railroads from A or B to other stations - other paths of the railroad are still there (normal white matter in the brain).
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If a landslide occurred and blocked the railroad from A to B, this doesn't affect the railroads from A or B to other stations - other paths of the railroad are still there (normal white matter in the brain).
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And now, all the train motorman needs to do is to take a detour to get from A to B (that is, altered functional connectivity in the brain)
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If you're interested in learning the details, you can read the work here: https://www.nature.com/articles/s41598-020-78394-z
And again, I want to thank my colleagues and the families and patients that allowed me to work with them on this project
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And again, I want to thank my colleagues and the families and patients that allowed me to work with them on this project
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