Thanks for your post, and welcome to NeuroBB!
As you may have seen from our blog, we found no indication of entrainment in our (very preliminary) binaural beats experiment. It is easy to imagine that there would be a powerful placebo effect from binaural beats, especially when combined with other activities that are known to have neurological and phenomenological effects (such as meditation).
That said, skeptical opinions have to be taken with a grain of salt as well! The lack of articles in appropriate journals could indicate an effect that is under studied, rather than non-existent. (If there were neuroelectrophysiology papers on the topic, but they found no effect, then we’d have reason to believe that there was nothing to investigate.)
In our experiment, we were not even asking what subjective or behavioural results might be had from binaural beats — all we’re trying to determine is whether they entrain “brain waves” in the first place!
Thanks for the link to the paper from Fontolan et. al. I think it’s quite interesting that the mechanisms of information transfer in the context of predictive coding are being discussed in terms of frequency, rather than in terms of lower-level neuron firing activity, or “binary” signals in neural networks.
I’m not at all familiar with the predictive coding literature, so this was a surprise to me.
It seems conceptually simple to unmix B-U higher frequency and T-D lower frequency signals if we think of them as analogous to electrical signals in a wire, but I find it a little daunting to imagine how this relates to the lower level activity (ie, action potentials in neurons) that underlies the oscillations. Crudely put, how does the system know that this action potential is part of some frequency-specific signal, while that one is not? Or are the spectrally-divided signals somehow independent and not a function of neuron firing at all?
To ramble approximately back to the topic, I think one of the most interesting things about binaural beats is that the beat frequency is subjectively audible. Pourquoi? It seems to indicate that the neural signals from the two ears are summed at some point while they are still closely related to the incoming audio waveform, which raises a whole raft of interesting questions about how audio is processed in the brain, and how that relates to what we perceive. Is there is an established understanding of why we hear a binaural beat frequency?