Figure 8. Unsupervised learning finds solution for global remapping.

A, Learning yields solution rapidly. Noisy spikes were added and plasticity turned up during the initial exposure, then lowered for the next 6min of learning. Spike maps show initially unstructured spikes and the rapid emergence of a clean place field. “Probe” refers to a simulation without plasticity after learning in both boxes was complete. B, Post-hoc analysis of weights plotted versus normalized offset, which were computed relative to the place field that emerged in the learning period. C,D, The network was then exposed to a second novel environment under the same conditions. In this example, a place field emerges in the second box in a different location. E, Summary of place field emergence in 200 repetitions of learning in both environments. Shown are the fraction of simulations in which the hippocampal cell expresses no place fields in either environment (“none”); in one, but not the other environment (“box1”, “box2”); or in both (“both”) environments.