Quian Quiroga’s recent letter in TiCS [1] raises a healthy debate about how the human hippocampus encodes episodic experience. We welcome the discussion and, while we respectfully disagree on several issues, we hope that it will stimulate experiments clarifying how the hippocampus encodes episodic memory. Here, we address four issues about hippocampal coding and argue that: (i) single-trial reinstatement is a statistically robust, widely used measure; (ii) episode-specific neurons (ESNs) cannot be explained as reactivated concept cells; (iii) repeated-story paradigms are ill-suited to test one-shot conjunctive coding; and (iv) concept cells alone cannot disambiguate similar events.
