Analysis of the memory trace nature in passive avoidance response

Passive avoidance conditioning is analyzed in a three compartment apparatus that consists of a light compartment, a dark dangerous compartment in which foot shock was delivered, and a dark safe one where the rats were not shocked. It is concluded that latency increase of passive response is caused not by memory of the shock in a strictly certain location and, accordingly, not by shock avoidance in it, but by non-specific defensive response (freezing) unrelated to the shock location.