Active experience, not time, determines within-day representational drift in dorsal CA1

Area of Science:

• Neuroscience
• Cognitive Science
• Memory Research

Background:

• Neural representations exhibit both stability for recall and plasticity for new information integration.
• Hippocampal spatial representations are known to be stable yet prone to long-term drift.

Purpose of the Study:

• To investigate whether active experience or the mere passage of time is the primary driver of representational drift in the hippocampus.
• To understand the dynamics of spatial representations in response to environmental engagement.

Main Methods:

• Comparing the stability of place cell representations in the dorsal CA1 region of the hippocampus in mice.
• Mice traversed two similar, familiar tracks for varying durations within a single day.
• Quantifying representational drift based on the time spent actively navigating the environments.

Main Results:

• Representational drift in spatial maps was directly correlated with the duration of active experience in the environment.
• This drift occurred irrespective of the total elapsed time between environmental exposures.
• Increased time spent traversing an environment led to greater drift in place cell representations.

Conclusions:

• Spatial representation is a dynamic process influenced by ongoing experiences within a specific context.
• Representational drift is primarily driven by memory update mechanisms rather than passive forgetting.
• Active engagement with an environment shapes its neural representation over time.