ABSTRACT
Wong et al. (2019) used a sensory preconditioning protocol to examine how sensory and fear memories are integrated in the rat medial temporal lobe. In this protocol, rats integrate a sound-light (sensory) memory that forms in stage 1 with a light-shock (fear) memory that forms in stage 2 to generate fear responses (freezing) across test presentations of the sound in stage 3. Here, we advance this research by showing that: 1) how/when rats integrate the sound-light and light-shock memories (online in stage 2 or at test in stage 3) changes with the number of sound-light pairings in stage 1; and 2) regardless of how/when it occurs, the integration requires communication between two regions of the medial temporal lobe: the perirhinal cortex and basolateral amygdala complex. Thus, “event familiarity” determines how/when sensory and fear memories are integrated but not the circuitry by which the integration occurs: this remains the same.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
This version of the manuscript has been revised after review at eLife. The revisions involved clarification of the methods used as well as minor edits to the Intro and Discussion to improve the flow of arguments.