Thread

1. itvision · 1789800711 · focus · HN ↗

   What a way to oversell the discovery.

   The reality is:

       * Different brain regions have different functions: ancient knowledge.
       * Different regions contain distinct cell types and molecular programs: also well established.
       * Anterior and posterior brain structures may trace back to fundamentally separate progenitor lineages that were independently specified very early in evolution and development: that's the interesting new result.
   

   The headline should have been: "Human forebrain and hindbrain arise from distinct embryonic progenitor lineages" - not that we have "two organs" in the brain.

   1. lucideer · 1789801887 · focus · HN ↗

      Given the parallel example cited in the article of jellyfish having two spatially separate organs, & the subsequent speculation that our own ancestors could also have had spacially separate anterior & posterior masses, the title doesn't really seem unreasonable in its hyperbole.

      While it might not be perfectly accurate it's hardly misleading.

      1. stymaar · 1789802377 · focus · HN ↗

         I found the title confusing, at the very least because it can be argued that the two brain hemispheres are two organs already, as they operate independently when severed from each other.

         1. finghin · 1789815685 · focus · HN ↗

            Totally valid point just as both kidneys are separate organs

            1. foo-bar-bat · 1789823685 · focus · HN ↗

               This is not a good analogy, because both kidneys do the same thing and we don't need both of them to live.

               Whereas the left and right brain hemispheres do different things that enable our species to be what it now is; which is more similar to what the article calls hind and fore/front brains, which again do different things that we wouldn't be us without. We would still be human if we had only one kidney the way we have only one bladder or one pancreas.

               Kidneys are more like say lungs, gonads, breasts, or nostrils in that we have +1 extra; but the benefit created by multiplicity is ~doubling or capacity and resilience to local disease and random injury-- not a profound functionality. (Like is created by the second eye or second leg.) Of these, the second breast is radically more useful than the second kidney, and is probably a special case as it changes how we live so evolved.

               1. finghin · 1789852318 · focus · HN ↗

                  I see the point, and understood it when I wrote my comment. However, as far as I know (and I could be wrong), there is no characteristic of either cerebral hemisphere determined at the embryonic stage that differentiates one from the other. As such the two hemispheres become functionally distinct but are not functionally distinct in principle or by virtue of being left or right.

                  Also, as others point out, hemispherotomies and -ectomies and to a lesser extent corpus callosotomies show that neither hemisphere nor their intercommunicative ability are strictly necessary for brain function. Yes, for ideal function, but that can be said of kidneys too.

                  Do add to this if you can argue against it.

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