Thanks for those points; I hadn’t read the paper in detail until now.
In terms of points of disagreement with HTM, it looks like they’re seeing a sort of temporal pooling going on in L2/3: this agrees with broad HTM theory, but I think the current implementations wouldn’t exhibit this.
Currently, the set of active cells is selected based on the previous set, and so even for sequences that are themselves first-order, the L2/3 population, which is envisioned to model higher order sequences, would preserve contextual information about the whole history of the sequence.
Do you think this is an analysis effect introduced by the fact that they’re averaging over trials? Maybe on average you’ll see the same set of cells active at the same times, even though on a trial-by-trial basis they depend on the whole history of the TM population.