Can you hear your own brain? Of course, you cannot. I nevertheless find myself returning to this fascinating play of thought. We often talk of “brain waves”. This is most likely inspired by the old images of electroencephalographs (“EEG”) that recorded electrical voltage changes straight from a participant’s scalp and scribbled them onto meter-long papers. Here is a picture from Berger’s famous first publications in the late 1920s:
This simple observation holds of course various truths about the brain. First, the brain looks messy when you try and plot its ”output” without further analysis or decomposition techniques at hand. Second, it does look like waves. There seem to be inherent waxing and waning, a rhythm, or as physicists (I am not one, in case you wondered) call it, “oscillations”.
[As an aside, please also note the smallish, much more regular oscillation at the bottom; it was Berger’s way of recording regular time intervals. Each small wave indicates 1/10 of a second in a pre-digital, pre-sampling age.]
Developing a fascination with these waves can now take you down (at least) two different paths from here.
One path is the path of brain science and in particular the study of neural oscillations. This is the path I and many colleagues trod every day. It holds a lot of frustrations: Brain rhythms are nowadays comparably easy to quantify but hard to understand. Of course, the brain pays you back for this with even further fascination: How can different brain areas “broadcast” at what looks like all the same frequency range, for example, alpha, 8–13 cycles per second, without creating simply mayhem amongst each other? And in what relation do these prominent alpha oscillations really stand to psychological phenomena such as attention and short-term memory? I hope you are not too surprised to learn that -- unlike what you’ll read on dodgy websites that sell “relaxation” audio CDs -- we do not really have a clue.
[By the way, the alpha-frequency range got first known as the “Berger rhythm” and received its final name probably because it was discernable easiest. If you eyeball the upper figure you will see that some of the brain peaks and troughs nicely coincide with the 1/10-second time code’s peaks and troughs below, so roughly 10 cycles per second.]
I look forward to share more of my fascination, not to say: obsession, with the oscillating brain in future posts. One could spend hours chatting on the waxing and waning of activity and its meaning on the cellular level, the neural cell assembly level, as well as on the macroscopic level of an entire scalp.
The second path of fascination with these waves that I wanted to mention briefly, however, is the analogy I started out with: Brain waves are fluctuations of voltage, measured with an EEG. As such, they are not that different from fluctuations of air pressure, vulg.: Sound, which can be picked up by our ears -- if they are amplfied accordingly and if they are fast or slow enough to hit our inner ear’s sensitive range, that is.
The idea of making brain waves audible is an old one. And since brain oscillations are not restricted to this low-frequency range below our ear’s hearing range (we start to pick up sound waves not before they start to oscillate at 20 cycles/second, roughly) but actually spread an entire range well up into the audible spectrum, it is both good clean fun and mesmerizing to “listen” to the brain.
Nowadays, it it very simple to write out digitized brain noise as an audio file and play it. Needless to say that the effect is much more visceral if you use big speakers that convey some of the infra-sound, haunted-house-style static that your own brain is emitting (“like David Lynch, only better”, a befriended artist called it).
For today, I will close by giving credit to Alvin Lucier, who -- much before my simple hat tricks -- famously used his brain waves and the infra-sound reverberations they create to drive and rattle all kinds of instruments he gathered on stage around him (“Music for Solo Performer”, 1965). They could not help but resonate with Alvin’s brain. -- I hope you keep resonating with mine!