Well here's something new to me. The idea that cholesterol is important in brain function. I'm cetainly reluctant at the moment to follow the many current dietary trends from low carb, to high carb, to paleolithic because I just don't think all the results are in. This little article givesa little insight into why obliterating cholesterol from your body may not be the most well thought out plan http://www.cholesterol-and-health.com/Memory-And-Cholesterol.html .
It's basic biology 101 that cholesterol is part of the basic cell wall and thus is a key structural element of the body. The concept that it's involved in more than just structure is no surprise.
It's interesting to me to note the implications of this study. As I said at the start I'm not convinced so far by the claims of any dietary approach because I feel no approach is without it's side-effects. What I feel is that well adapted lifestyles simply find ways to deal with the side effects to ensure the whole functions properly and free from disease. If cholesterol is required to support brain function and repair. then it seems logical to me that at times where a lot of brain repair is required there would be a lot in the blood and thus the person would show high levels of cholesterol. Yet this may not indicate a cause of the problem, it may actually represent the solution.
Cholesterol levels would be raised even higher if other areas of the body also required cholesterol to help their daily functioning. This seems plausible given the role it plays in various parts of the body http://en.wikipedia.org/wiki/Cholesterol#Synthesis_and_intake.
On the whole I've come to form the view that many of the diseases of westernisation may be caused by the mind and body not being given sufficient resource or time to recover from daily stresses and that so many of the indicators we currently use for disease simply reflect the bodies response to this stressed staight where repair and recuperation are desperately needed.
I don't konw how long that view is going to survive but it's fascinating to me that everywhere I look this view just seems to fit like a glove.