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Title: The Brain Is Actually Two Completely Separate Organs

Link: https://science.slashdot.org/story/26/09/20/0...

"New research led by Stanford Medicine reveals that what we call the brain is
two distinct organs that evolved independently over hundreds of millions of
years," Stanford Medicine announced this week: The new research finding shows
that the human brain consists of two ancient nervous systems cleverly
packaged together - a more primitive part that regulates our hearts' beating,
our breathing and other functions, and another that makes us distinctly
human, capable of poetry, mathematics and wondering about our own origins.
The discovery could help explain why scientists have struggled for decades to
grow certain types of brain cells in the laboratory - and it opens new
avenues for studying devastating diseases that affect the brain stem...
[S]cientists have struggled for decades to generate human hindbrain neurons
in the laboratory. This gap has hampered research into devastating diseases
affecting the brain stem, including spinal muscular atrophy and amyotrophic
lateral sclerosis... The researchers' breakthrough came from studying the
earliest moments of embryonic development... [Study co-authors Carolyn Dundes
and Rayyan Jokhai] discovered that the hindbrain follows a separate
developmental path, running in parallel to - rather than branching off from -
the pathway that creates the forebrain and midbrain... This revelation
explained decades of frustration in the field - scientists had been trying to
turn one type of progenitor cell into another that it is fundamentally
incapable of becoming... Armed with this knowledge, the researchers for the
first time successfully coaxed human pluripotent stem cells (a kind of cell
that can create any cell in the human body) to become functional hindbrain
motor neurons in the laboratory... Finally, the researchers looked back over
550 million years of evolutionary time. They found the same two-origin brain
pattern in chickens; zebrafish; and, remarkably, in acorn worms, tiny
creatures living on the ocean floor that share a distant common ancestor with
humans. Jellyfish, which diverged from humans about 600 to 700 million years
ago, have two nervous systems at different ends of their body. "Our research
suggests that evolution took two existing neural systems and pushed them
together spatially," Loh said. "Having the brain as one organ would probably
be more efficient, but we rely on this primordial way to make the brain as
two separate pieces." Thanks to Slashdot reader Beeftopia for sharing the
article.

Read more of this story at Slashdot.

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