In my introductory post to this blog I suggested that I may from time to time post whimsical explorations of how we might create better functional neuroimaging technology. So today I am posting a paper which I have written on the potential of using acoustic waves in combination with magnetic field measurement to image current density. Think of it as acoustically encoded magnetoencephalography (MEG). I don’t know if whimsical is good description of the project but it is definitely an exploration of how we might create better functional neuroimaging technology. And if whimsical is an appropriate description then I contend that whimsy, especially principled and rigorous whimsy, is something that the field of neuroimaging needs.

My hope is that I will get some feedback on this paper prior to publishing it in ArXiv or elsewhere. Any comments and suggestions are welcome. I hope you find this paper stimulating and a source of new ideas.

The basic idea contained in the paper is that measurements of the magnetic field exterior to a region containing a compactly supported current density source (Generated by neuronal processes in the case of the brain.) give us very little information about the current density (I estimate how much in the paper.). So we need an additional means of spatially encoding current density to supplement the spatially encoding information contained in the external magnetic field data. This additional encoding is provided by a propagating acoustic wave which perturbs the current density.

The proposed system is highly idealized but I had to start somewhere tractable. If experiments or detailed simulations based on the highly idealized model could be carried out successfully then moving away from the idealized model to one which more resembles the brain could be the focus of further investigations.

You can find the paper here: meg_us