There is a growing faction in the neurodegenerative research community whose members think it likely that rising levels of metabolic waste in brain, such as tau and amyloid aggregates, are due to failing drainage of cerebrospinal fluid. That drainage is a primary method of removal, and as it declines the wastes build up. The Methuselah Foundation is somewhat ahead of the game here, having incubated Leucadia Therapeutics to develop a possible solution. A number of other groups have turned their attention to this topic, and it has been interesting to see a flurry of papers in the last year or so. The work noted here is related, though the researchers are looking at circulation of cerebrospinal fluid within the brain, driven by cardiovascular activity, rather than drainage. The open access paper - worth looking at, but very dry - describes a low-cost way of assessing this flow and some exploration of the findings. Their measurements start to show changes at a comparatively early age, much earlier than one would expect for a process linked to cardiovascular function. This is quite interesting, though it is far too early to do more than speculate on why this might be the case.
Physicists have devised a new method of investigating brain function. This new non-invasive technique could potentially be used for any diagnosis based on cardiovascular and metabolic-related diseases of the brain. The researchers deciphered oscillations in the cerebrospinal fluid which lies between the scalp and skull; a device for non-invasive recordings of this translucent fluid was developed and recordings on healthy subjects were made.
It has been shown that the circulation throughout the brain of this fluid is highly fluctuating, and that these fluctuations are slow but interconnected by the rhythms of breathing and the heart rate. Researchers found that some of these oscillations are linked with blood pressure, but are generally slower, occurring at lower frequencies, which have been shown in previous studies to be related to oscillations in vascular motion and blood oxygenation.
Preliminary results showed evidence of a decline in the coherence between these oscillations in participants over the age of 25, indicating that brain ageing may begin earlier than expected. "Combining the technique to noninvasively record the fluctuation corresponding to cerebrospinal fluid and our sophisticated methods to analyse oscillations which are not clock-like but rather vary in time around their natural values, we have come to an interesting and non-invasive method that can be used to study ageing."