The first Law of Science is that any Law of Science is an act of hubris and (potentially) wilful ignorance.
Nowhere does this seem to be truer than in matters pertaining to the human brain.
For some reason—perhaps tied to humanity’s faith in reason and logic—this organ holds a sacrosanct status over every other in the human body.
Thus, it is perhaps no surprise that when University of Alabama at Birmingham’s Rosalinda Roberts presented her findings at Neuroscience 2018 back in November, they were met with skepticism. Roberts, you see, had electron micrographs that showed bacteria in brain sections not just from people with disease, but also from healthy individuals.
My introduction to this idea did not start in San Diego with this announcement. Off and on, I had seen several references to a potential brain microbiome, and almost to a mention, my notice was piqued by the rabid attack of the subject.
“Brain microbiome?” one social media commentator barked. “It’s called an infection!”
Not a neuroscientist, I am not really in a position to judge the validity or heresy of the discovery. Even Roberts suggest that there is much work yet to do.
I am struck and saddened, however, by the speed and tenor of the attack on the findings, and perhaps on the scientists themselves.
It reminds me of the earliest days of the conversations about prions. Here, it was less a concern that the particles were in the brain—protein aggregations in neurological tissues are sadly not new—but rather than they seemed to be infectious pathogens and yet were devoid of nucleic acids.
How can you have a transmissible element that replicates itself in the absence of a nucleic acid intermediate? Protein cannot beget protein, they bellowed. It is a Law of Science.
I remember following this saga as an undergraduate student, never fully understanding the pathology, but fully engrossed in the debates.
The truth, as it played out, lay somewhere between canon and controversy with misfolded protein catalyzing protein misfolding, leading to aggregation and disease pathology.
I will not be surprised if “microbes on the healthy brain” will follow a similar trajectory.
Other sessions at Neuroscience 2018 showed us how intimately connected gut microbes are to host brains, whether healthy or diseased. And my recent exploration of the blood-brain barrier (August 2018’s Special Report on Drug Delivery) opened my eyes to the ability for compounds to circumvent the BBB via nerve fibers.
Likewise, my research and interviews for this month’s Special Report on Microbiomics (starting on page 20 of the physical issue or the PDF of the January 2019 issue if you're perusing either of those when you get around to reading it), highlighting the connections between microbes and the human immune system both in sickness and in health, further added to my belief in a community of well-being.
For microbes to not only figure out a pathway into the human brain—but also for the interactions along that pathway to be symbiotic rather than purely pathogenic—would surprise me not in the least. Others, however, have yet to open themselves to that possibility.
We cannot discover—and will not discover—what we “know” cannot exist.
When we are so beholden to our knowledge—or more accurately, our beliefs wrapped in logic and rational thought—we disbelieve or ignore what our instruments and senses tell us.
Perhaps, in this sense, it is not the alley that is blind, but rather those who look into it and refuse to see.
Randall C Willis can be reached by email at firstname.lastname@example.org