They may be a shortcut for the immune system. From ScienceDaily:
“We always thought that immune cells from our arms and legs traveled via blood to damaged brain tissue. These findings suggest that immune cells may instead be taking a shortcut to rapidly arrive at areas of inflammation,” said Francesca Bosetti, Ph.D., program director at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS), which provided funding for the study. “Inflammation plays a critical role in many brain disorders and it is possible that the newly described channels may be important in a number of conditions. The discovery of these channels opens up many new avenues of research.” Paper. (paywall) – Fanny Herisson, Vanessa Frodermann, Gabriel Courties, David Rohde, Yuan Sun, Katrien Vandoorne, Gregory R. Wojtkiewicz, Gustavo Santos Masson, Claudio Vinegoni, Jiwon Kim, Dong-Eog Kim, Ralph Weissleder, Filip K. Swirski, Michael A. Moskowitz, Matthias Nahrendorf. Direct vascular channels connect skull bone marrow and the brain surface enabling myeloid cell migration. Nature Neuroscience, 2018; DOI: 10.1038/s41593-018-0213-2More.
What’s this about “crosstalk”:?
“While we’ve still got a lot to learn about these channels, I think their very special role as conduits for inflammatory cross-talk between the marrow and the central nervous system is quite different from any other vasculature,” Nahrendorf says in an MGH statement. “In addition to these channels carrying immune cells from the skull marrow to the brain, we think inflammatory substances that derive from the brain may alert the skull marrow to an injury faster than marrow from the rest of the body.”Ashley Yeager, “Tiny Tunnels Run from the Skull to the Brain: Study” at The Scientist
Given the enormous (and often previously unknown) complexity of the systems that, we are told, somehow evolved randomly via natural selection acting on random mutations (Darwinism), it’s a wonder we don’t see rocks just somehow slowly coming to life… Unless maybe…
See also: Unique type of cell found in human brain: rosehip neurons Researchers: The study hasn’t proven that this special brain cell is unique to humans. But the fact that the special neuron doesn’t exist in rodents is intriguing, adding these cells to a very short list of specialized neurons that may exist only in humans or only in primate brains.