An article in Scientific American discusses the debate about whether brain waves have a function or whether they are an epiphenomenon:
Do Brain Waves Conduct Neural Activity Like a Symphony? There are so many things wrong with this debate.
We know so little about how the brain functions. To dismiss observable signals as an epiphenomenon assumes a level of knowledge that no one has. It is merely a defense of the status quo paradigm, straight out of Thomas Kuhn. The attitude boils down to “they don’t play a role because we kind of already know how the brain works”. No, you don’t. No one does.
What do neurons do?: They spike when their membrane potential reaches the spiking threshold. What do oscillations do? They move the membrane potential towards and away from the spiking threshold. You start with the assumption that oscillations matter, not that they don’t. The latter is just a defense of what you think you already know. That attitude holds back progress.
The article says that “critics point out that oscillations arise everywhere one looks in nature” so therefore brain oscillations are not functional. To my mind, that is an argument *for* a functional role. Evolution builds on what is already available.
Critics also say that there is not a lot of evidence for a link between oscillations and mental states. Yes, there is. There are more and more papers published each week. There might be more evidence for spiking but that is just because spiking has been studied longer. The same type of correlational evidence is there for both spikes and oscillations. As for the lack of a causal role between oscillations and brain function, the evidence for a causal role between spiking and function is equally flimsy. Spiking is not the gold standard just because it is the first and easiest thing we could measure when we only had single-channel amplifiers and slow or no computers.
Skepticism is a good thing but where is the skepticism about the notion that spikes do it all? For example, consider the following quote from the article: “evidence amassed so far is not based on rigorous tests looking for a cause-and-effect relationship between gamma waves and specific neural processes.” The same statement is equally true for cause-and-effect between spikes and function. Somehow that gets a free pass? The oscillation naysayers accept their spikes-only model without question but set a high bar for others. I refer you back to Thomas Kuhn.
Spikes vs oscillations is not an either/or thing. They both work together. Indeed, it is hard to imagine how one would decouple them. The bottom line is that both spikes and oscillations are both signals. No one knows enough about how the brain works to dismiss the measuring of a signal. Since when is more data a bad thing?
About the Author
The Miller Lab uses experimental and theoretical approaches to study the neural basis of the high-level cognitive functions that underlie complex goal-directed behavior. ekmillerlab.mit.edu