Recent comments in /f/askscience

Scales-n-tails87 t1_j8yehpw wrote

Reply to Is blood toxic to neurons ? by AdEnvironmental8339

Dr liberman is my surgeon. He is works renowned and is very knowledgeable. He did my first done surgery, and my brain surgery. One thing I respect about him is that he has great bedside manner as well, and doesn't mind explaining things like this to people. I'm sure if you reach out to him, he would explain happily. But there are some good answers here already to sum it up pretty well. Blood is basically suffocating to the brain because of the clotting agents, and blood breaks down over time unlike cerebral spinal fluid. The breaking down of blood cells causes processes to happen that are not safe for the brain or spinal fluid.

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iayork t1_j8xrx6t wrote

Reply to If two people are infected with the same virus (or bacteria), do they produce the same antibody to defend themselves? If not, do some people produce more effective antibodies and why? by SupercriticalBalloon

Other people have answered correctly but the details are interesting (and I’m sitting in an airport waiting for my plane to arrive so I have time).

In the big picture, people generally produce “the same” antibodies in that almost everybody tends to target the same places on a pathogen protein. For example, H1N1 influenza viruses have 6-7 places that antibodies preferentially bind to, and different people all target those same places. They’re called “immunodominant” sites, and immunodubdominant sites are less well targeted.

(Because this is biology, nothing is ever 100%, so there are occasionally people who don’t target one or a few sites well, or people who are particularly good at targeting sites that are normally subdominant. Studying these people and understanding why they do this is an active area of research.)

So that’s the big picture, but if you drill down and look at the actual protein sequence of the antibodies that are doing the binding, they are not typically the same. Other comments have pointed to somatic hypermutation as a cause of this, but even ignoring SHM, most people have very different sets of responding antibodies. Antibodies are originally generated randomly, and it turns out that there are many ways to find very similar solutions - there may be billions of ways to get an antibody that binds to H1N1 immunodominant site “Sa”, say.

So if you compare the sequences of antibodies that are apparently doing the same thing - even between identical twins infected with the same virus at the same time - you won’t find much overlap.

But, drilling down yet another level, you will find some some overlap. We call the overlapping sequences, that are shared between different people, “public” sequences, and those that are not shared “private”.

The ability to sequence antibodies in this way is fairly new, with tech that really started to become widespread in the last ten years, so we are still trying to get a handle on the ratio of public to private sequences. If you look at two people, they may share no sequences; if you look at 100, you may find a couple dozen clusters that various people share; if you look at a thousand, who knows? It’s starting to seem that a significant percentage of antibodies are kind of public - someone else out there has something like it; but most are not widely public - it might only be shared among say 5% of the population.

Again, this is an area of very active research, with groups trying to understand the significance and potential uses of public vs private sequences.

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skatergirl69420 t1_j8x9nhc wrote

Reply to Are the two sides of the brain symmetrical in shape/folds ? by freezeframepls

im assuming by “types of folds” you’re referring to the gyri and sulci (in simple terms, a gyrus (gyri plural) would be the outward-appearing lumps/bumps, and a sulcus (sulci plural) would be the deeper grooves inward)

despite the brain being split in two hemispheres down the middle by the longitudinal fissure, hemispheres are only symmetrical to an extent. structural asymmetry varies between individuals, brain regions, etc. so the short answer to your question is no

however, it of course follows the same structure on both sides. the superior frontal gyrus is gonna be in approximately the same spot on either side, the uncus gyrus in approximately the same spot, the pre&post central gyri in approximately the same spot on either side of the central sulcus.

then, there can be differences in an individual due to disorders like pachygyria or microgyria (abnormally large or small gyri, respectively) which can span the entire cerebral cortex or be localized.

if some functions are processed more in one hemisphere than another, that would impact symmetry. interestingly, some studies have shown that a LACK of left hemisphere asymmetry is observed in individuals with dyslexia. some research also found that the asymmetry between hemispheres is not due to genetics, so its believed to be due to experiences

another factor that can affect the symmetry/asymmetry between hemispheres is if a portion of the brain that is typically for “xyz” function is also working for “abc” function. if a region has greater between-subject variability, its more likely to be asymmetrical to its respective location in the other hemisphere.

heres an article if u care to read more:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947520/

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