The object space task shows cumulative memory expression in both mice and rats

• Published in: PLoS biology Vol. 17; no. 6; p. e3000322
• Main Authors: Genzel, Lisa, Schut, Evelien, Schröder, Tim, Eichler, Ronny, Khamassi, Mehdi, Gomez, Angela, Navarro Lobato, Irene, Battaglia, Francesco
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17-06-2019; Public Library of Science (PLoS)
• Subjects: Animal memory; Animals; Behavior, Animal - physiology; Biology and Life Sciences; Learning; Life Sciences; Male; Memory; Memory - physiology; Memory, Long-Term - physiology; Mental task performance; Methods and Resources; Mice; Mice, Inbred C57BL; Neurons and Cognition; Paradigms; Physiological aspects; Rats; Rats, Wistar; Recognition, Psychology - physiology; Research and Analysis Methods; Rodents; Semantics; Social Sciences; Software; Space Perception - physiology; Spatial Memory - physiology; Supervision; United States; Netherlands
• ISSN: 1545-7885; 1544-9173; 1545-7885
• DOI: 10.1371/journal.pbio.3000322

Declarative memory encompasses representations of specific events as well as knowledge extracted by accumulation over multiple episodes. To investigate how these different sorts of memories are created, we developed a new behavioral task in rodents. The task consists of 3 distinct conditions (stable, overlapping, and random). Rodents are exposed to multiple sample trials, in which they explore objects in specific spatial arrangements, with object identity changing from trial to trial. In the stable condition, the locations are constant during all sample trials even though the objects themselves change; in the test trial, 1 object's location is changed. In the random condition, object locations are presented in the sample phase without a specific spatial pattern. In the overlapping condition, 1 location is shared (overlapping) between all trials, while the other location changes during sample trials. We show that in the overlapping condition, instead of only remembering the last sample trial, rodents form a cumulative memory of the sample trials. Here, we could show that both mice and rats can accumulate information across multiple trials and express a long-term abstracted memory.