In this series of blog posts, we plan to give insights to the thinking and ideas related to BREAKBEN that cannot be easily presented in typical scientific articles. In blogs, the word is free—there is no peer review; we can be more informal.
The BREAKBEN project is a profoundly technical: one has to push the boundaries of possibility toward their utmost limits. One has to understand and take advantage of the peculiarities of MRI, one has to get close to the quantum-mechanical limit of sensitivity when developing SQUID magnetometers, one has to invent ways to handle the effects of strong MRI fields without disturbing the ultra-sensitive SQUIDs. We will learn about some of the technical challenges in subsequent blog posts.
It may be worthwhile to ask: What is the long-term vision that motivates BREAKBEN? Why are we doing this? Why should taxpayers pay for this? Why should some of the best researchers and scientists work on building another expensive piece of machinery?
BREAKBEN aims at “breaking the nonuniqueness boundary of in electromagnetic neuroimaging”. This is a paradoxical-sounding goal. Helmholtz already in the mid-1800’s proved that the solution of the inverse problem is nonunique: No matter how you measure the electric and/or magnetic fields on the surface or outside a conducting body (such as the head), you will not be able to uniquely determine what the sources of the fields are. In fact, there is an infinite class of solutions to the inverse problem, with wildly different properties. On the other hand, it is clear that MEG and EEG give us spatial and temporal information about the activity in the brain.
The solution of the inverse problem can be made unique if the measurement data are combined with a sufficient amount of supplementary information that constrains the space of possible solutions. This is already an old notion but the problem remains that usually the a priori information is unreliable: often, mere assumptions are made about the nature of the sources; at other times spatial constraints are given. In the latter case, the inaccuracy in knowing the relationship between the coordinate systems of MEG and MRI degrades the value of the a priori information.
If BREAKBEN succeeds in its technical goal of providing first-class functional MEG signals, high-quality MR images, conductivity information and neuronal current data, one can start a serious effort to take advantage of the wealth of supplementary information that may be available for the solution of the inverse problem.
BREAKBEN is a Horizon 2020 Future and Emerging Technologies (FET) project. FET funds only risky projects that have a potentially major impact. BREAKBEN is risky—its technical challenges are staggering. Its impact will eventually be in neuroscience and clinical diagnostics. Accurate and reliable information of patients’ brain activity is urgently needed as new treatment options become available. Somebody should push the necessary technology forward. This consortium may be the best in the world to tackle this challenge: it has leading expertise in MEG and its applications, in SQUID technology, in phantoms and in the mathematical theory of the inverse problem and signal analysis. It can push the boundaries of possibility.