| Oh my this article is painful to read on so many levels. It treats as important many phenomena that are either inevitable or uninteresting. (1) The fact that engaging in one task distracts attention from another task is obvious. People derive inspiration from taking a shower, swimming, biking, playing music and yes, walking. All these tasks have something in common, they are different from whatever task one was doing beforehand, and they require less cognitive focus than many of the things that we do for work. (2) The fact that noise in the brain is 1/f is not particularly interesting. Many natural systems have 1/f amplitude spectra. This pattern occurs commonly in multi-scale systems (the brain being one example). (3) The fact that many aspects of brain activity (both signal and noise) are affected by aging, consciousness, mental experiences, memory and so on is not particularly interesting. Assuming that one is not a dualist, every distinct mental state must be reflected by some unique pattern of brain activity. (4) Scientists know quite a bit about where these “spontaneous fluctuations” come from. Many of them are a consequence of changes in blood pressure, which varies substantially and randomly over time (within some finite band, of course). Others are caused by mental states that are difficult to measure and model, and so are unknown to the experimenter. But just because something is noise from the perspective of the experimenter doesn’t mean that it is noise from the perspective of the brain. |