Theta and gamma oscillations in the rat hippocampus support the discrimination of object displacement in a recognition memory task.

Episodic memory depends on the recollection of spatial and temporal aspects of past experiences in which the hippocampus plays a critical role. Studies on hippocampal lesions in rodents have shown that dentate gyrus (DG) and CA3 are necessary to detect object displacement in memory tasks. However, the understanding of real-time oscillatory activity underlying memory discrimination of subtle and pronounced displacements remains elusive.

Rats recognize spatial and temporal attributes in a new object recognition memory task with multiple trials.

Background: Episodic-like memory tasks based on the spontaneous exploration of objects are commonly applied in one-trial protocols. However, multiple-trial designs are known to reduce animal numbers and data variance, providing faster accumulation of data.

New Method: In this study, we devised a new object recognition memory task for rats that carry out multiple trials per session.

CA1 inactivation impairs episodic-like memory in rats.

Episodic memory was initially believed to be unique to humans. However, studies demonstrate that nonhuman species discriminate items based on the triad what, where and when. Here we addressed the role of the dorsal hippocampal subfield CA1 in an integrative what-where-when task in Wistar rats.