The hippocampus and memory for "what," "where," and "when"

Area of Science:

• Neuroscience
• Cognitive Science
• Animal Behavior

Background:

• Nonhuman animals may possess episodic-like memory, recalling event details like "what," "where," and "when."
• Previous research has not identified the specific brain structures underlying this capacity.

Purpose of the Study:

• To investigate the neural basis of episodic-like memory in rats.
• To determine the role of the hippocampus in integrating "what," "where," and "when" information.

Main Methods:

• Rats were trained to remember single episodes involving odors presented in specific locations.
• Lesions of the hippocampus were created in a subset of rats.
• Probe tests assessed the use of olfactory and spatial cues to recall event order.

Main Results:

• Normal rats effectively used both spatial and olfactory cues to recall the timing of events.
• Rats with hippocampal lesions were impaired in integrating these cues, despite retaining individual cue perception.
• Memory for individual "what" (odor) and "where" (location) cues was largely preserved post-lesion.

Conclusions:

• Rats demonstrate the ability to integrate "what," "where," and "when" information in memory for single events.
• The hippocampus is critical for this integration and the formation of episodic-like memories.