What would “memory decoding” in the MICrONS data set imply?

Attention conservation notice: Not an area of expertise for me. Posted as in the spirit of Cunningham’s Law.

The recently posted MICrONS data set has functional imaging on 75,000 pyramidal neurons and EM-level anatomic data on 120,000 neurons.

Layer 2/3 cells from the MICrONS data set; screenshot from https://ngl.microns-explorer.org/

As the preprint describes: 

“The volume was imaged in vivo by two-photon microscopy from postnatal days P75 to P81 in a male mouse expressing a genetically encoded calcium indicator in excitatory cells, while the mouse viewed natural movies and parametric stimuli. At P87 the same volume was imaged ex vivo by serial section EM. Because the light and electron microscopic images can be registered to each other, these primary data products in principle contain combined physiological and anatomical information for individual cells in the volume, with a coverage that is unprecedented in its completeness.”

https://www.biorxiv.org/content/10.1101/2021.07.28.454025v2

As far as I can tell, it is an open question the degree to which the serial section EM can be used to predict the functional imaging data in this data set. But one might imagine that the EM data or wiring diagram could be eventually used to identify ensembles of neurons that respond to specific visual stimuli. If this could be shown, would it count as memory decoding? 

One of my neuroscience professors in grad school, Matthew Shapiro, spoke of “memory in the everyday sense of the word.” If we were to go up to a layperson and tell them that we had identified functional neuronal ensembles based on anatomic EM data to a sufficient degree of accuracy, they would probably not think that this meant that we had decoded a memory.

However, maybe they would be not be appreciating the eventual implications. Perhaps this ultimately is the core of what will eventually be required for memory decoding in the everyday sense. To me, this seems like somewhat of an open theoretical question.