In a stunning discovery that overturns decades of textbook teaching, researchers have determined that the brain is directly connected to the immune system by vessels previously thought not to exist. The discovery could have profound implications for diseases from autism to Alzheimer’s to multiple sclerosis.
h/t Chuck
From yesterday’s The Sound of Settled Science: “Writing in The Lancet last month, editor Richard Horton argued that as much as half of all scientific papers may simply be ‘untrue.'” So this here research is 50-50 whether it’s true or not.
It’s getting tougher and tougher to make evidence-based decisions when the evidence keeps changing all the time.
This however changes everything.
Makes perfect sense to have a redundant immune system in the critical organ of the brain
I was never aware that the lymphatic wasn’t believed to be in the brain
I live for the day science finally discovers the mechanics behind a phenomena we have all known for decades – that the prog brain is directly wired into their rectum
99% of everything we learn eventually gets proven wrong. We just need to go with the evidence and a good gut feel but always be prepared to change.
Maybe this will explain some of the ossified old dinosaur brains that haunt this place.
Not really that big a deal as the field of psychoneuroimmunology has been around for a couple of decades now. What’s neat about lymphocytes is that they form little computational clusters where a bunch of them get together send out thin cytoplasmic extensions to one another (immunologic synapses) and exchange proteins with each other. Then the little cluster breaks up and they go on their way to create some form of immune response.
The current theory is that cytokines, chemical messengers that lymphocytes use, affect the brain although this is a rather crude means of control. One theory of depression is that it reflects abberrent sickness behavior. Some cytokines put the brain to sleep and anyone who’s had a sick pet knows there’s something wrong when the cat heads for a remote location and goes to sleep for a long time. This response is likely to conserve energy to let the immune system fight an infection. C reactive protein (CRP) is sometimes elevated in human depression (this is a protein whose levels go up in the case of bacterial infections or inflammatory disorders) and the nice thing about depressed people with high CRP’s is that one has an objective marker with which to assess antidepressant response as drops in CRP are associated with clinical mood improvement.
What the demonstration of brain lymphatics does is to indicate that the neuroimmunologic connection is finer grained than initially thought. The primary immune system in the brain consists of microglia and these are activated a number of neurologic disorders. Their activity can be decreased by unexpected side effects of drugs such as minocycline and low dose naltrexone.
When it comes to the brain, I’m glad that much of the dogma is being challenged. 30 years ago the first piece of dogma to go was the number of neurons in the brain – a famous quote from that era was “of the 10 billion neurons in the brain, 100 billion of them are granule cells in the cerebellum”. I used to have arguments with profs about the stupidity of neurons not dividing and now we know that olfactory lobe neurons divide constantly, hippocampal neurons divide in the formation of new memories and that depression is associated with lack of hippocampal cell division. We’ve gone from the simplistic notion of a neuron as equivalent to a logic gate in the 1960’s to a neuron as a networked system of microprocessors which operates on multiple levels ranging from quantum computation to slow chemical signalling between neuronal assemblages and glia have gone from mere supporting cells to the major part of the slow chemical computation system.
The day when humans think they have all the answers to everything in the universe including the mind, even how cognitive thought exists, will be the day before we extinguish our species.
I was wrong once.
The number of outright reversals, never mind changes, that I have witnessed in my 35 years in Medicine have turned me into a huge cynic of the scientific world.