Mapping and Deciphering Neural Codes of NMDA Receptor-Dependent Fear Memory Engrams in the Hippocampus
(A) Hierarchical clustering method revealed categorical and combinatorial response patterns in recorded CA1 units from the control mice. Nonresponsive units and units responded to CS and US during learning and to the conditioned tone at recall were listed vertically (a total of 1147 units from 5 five control mice). (B) Global responses of all recorded CA1 units from the knockout mice (a total of 1153 units from 5 five knockout mice). Color scale bars indicate the logarithm transformed responsiveness of hippocampal units averaged over seven trials (see Methods).