How deep is our ignorance of the brain? We have just had another surprising discovery that shows how little we know. There is a whole physiological system in the brain, the size of the brain’s vascular system (all the arteries and veins in the brain) and the importance of the lymphatic system for the rest of the body. The system circulates cerebral spinal fluid at a speed and clears waste from the brain. (Citation below)
Of course there is a reason why it went unnoticed – it does not exist unless the brain is whole and working. That is not the only reason: it was difficult to see until recent advances in instrumentation; and, no one looked for it. But we have to notice that in general most of brain physiology does not exist unless the brain is whole and working and instrumentation is mostly new and problematic in neuroscience. It is a system made of astrocytes forming conduits outside blood vessels but following their path. Astrocytes have only recently been thought important to understand. These cells seem to wrap everything in the brain, not just protecting but also controlling and communicating. They are still understudied. This newly discovered system has been named glymphatic, a mixture of glia and lymphatic.
Regularly we have surprises like this. And we should by now recognized that it will be a few years before we have a somewhat complete model of the brain operations. This may be especially true of surprises having to do with consciousness.
There is a habit of rejection when it comes to surprises about consciousness. Libet was 30 years ago and there is still an industry in trying to disprove the results. This has resulted in more information and some changes in interpretation but still the gist of Libet’s experiments still stand. We register our decisions to act consciously, we take ownership of them, but we do not make them consciously, the decisions are formed before they are made conscious.
Note: again citation link is faulty. Try
Iliff JJ, Wang M, Liao Y, Plogg BA, Peng W, Gundersen GA, Benveniste H, Vates GE, Deane R, Goldman SA, Nagelhus EA, & Nedergaard M (2012). A Paravascular Pathway Facilitates CSF Flow Through the Brain Parenchyma and the Clearance of Interstitial Solutes Sci Transl Med : 10.1126/scitranslmed.3003748