A new paper, Beyond dimension reduction: Stable electric fields emerge from and allow representational drift, suggests that electrical fields generated by the brain stabilize mental representations. Here is the abstract:
It is known that the exact neurons maintaining a given memory (the neural ensemble) change from trial to trial. This raises the question of how the brain achieves stability in the face of this representational drift. Here, we demonstrate that this stability emerges at the level of the electric fields that arise from neural activity. We show that electric fields carry information about working memory content. The electric fields, in turn, can act as “guard rails” that funnel higher dimensional variable neural activity along stable lower dimensional routes. We obtained the latent space associated with each memory. We then confirmed the stability of the electric field by mapping the latent space to different cortical patches (that comprise a neural ensemble) and reconstructing information flow between patches. Stable electric fields can allow latent states to be transferred between brain areas, in accord with modern engram theory.
A press release from MIT has a more simplified description of the research.
I’ve noted several studies in recent years that demonstrate the lack of correspondence between subjects and over time in the same subject of neuron firings while the same task is being performed. To quote from the release:
Indeed, whenever neuroscientists have looked at how brains represent information in working memory, they’ve found that from one trial to the next, even when repeating the same task, the participation and activity of individual cells varies (a phenomenon called “representational drift”). In a new study in NeuroImage, scientists at The Picower Institute for Learning and Memory at MIT and the University of London found that regardless of which specific neurons were involved, the overall electric field that was generated, provided a stable and consistent signal of the information the animals were tasked to remember.
This observation aligns well with McFadden’s cemi theory and his prediction number 8. Different neural firings can produce the same or similar waveforms. A given firing will produce a defined waveform but the waveform itself cannot be reverse engineered to a definitive firing. The “representational drift” actually may be adaptive in that it is the brain’s way of trying to find a best fit for its representations through a conscious feedback process.