Single neurons in the human entorhinal cortex remap to distinguish individual spatial memories

How does the brain represent and differentiate memories that share a common context, such as separate experiences encoded in one environment? To answer this question, we recorded single neurons in the medial temporal lobe (MTL) of neurosurgical patients during cued recall of object-location memories in a virtual-reality environment. We observed cells that remapped their spatial firing fields to the location subjects were instructed to remember, reflecting a putative memory trace driven by the specific memory that was cued for retrieval on a trial. In addition to binding memories to locations in this way, the activity of these "trace cells" in entorhinal cortex was predictive of specific cued memories whether subjects were moving through the remembered location or were stationary at the start of the track. The influence of cued memory retrieval on the activity of entorhinal trace cells suggests their importance in representing and differentiating past experiences.