The rodent object-in-context task: A systematic review and meta-analysis of important variables

PLoS One. 2021 Jul 16;16(7):e0249102. doi: 10.1371/journal.pone.0249102. eCollection 2021.

Abstract

Environmental information plays an important role in remembering events. Information about stable aspects of the environment (here referred to as 'context') and the event are combined by the hippocampal system and stored as context-dependent memory. In rodents (such as rats and mice), context-dependent memory is often investigated with the object-in-context task. However, the implementation and interpretation of this task varies considerably across studies. This variation hampers the comparison between studies and-for those who design a new experiment or carry out pilot experiments-the estimation of whether observed behavior is within the expected range. Also, it is currently unclear which of the variables critically influence the outcome of the task. To address these issues, we carried out a preregistered systematic review (PROSPERO CRD42020191340) and provide an up-to-date overview of the animal-, task-, and protocol-related variations in the object-in-context task for rodents. Using a data-driven explorative meta-analysis we next identified critical factors influencing the outcome of this task, such as sex, testbox size and the delay between the learning trials. Based on these observations we provide recommendations on sex, strain, prior arousal, context (size, walls, shape, etc.) and timing (habituation, learning, and memory phase) to create more consensus in the set-up, procedure, and interpretation of the object-in-context task for rodents. This could contribute to a more robust and evidence-based design in future animal experiments.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Animals
  • Memory*
  • Rodentia

Grants and funding

This study was supported by ZonMW grant ‘Meer Kennis met Minder Dieren’ module (project #114024150) and the Dutch Ministry of Defense. MS is supported by a personal grant which is part of the Graduate Program (project #022.003.003) of The Netherlands Organization of Scientific Research NWO. MS and MJ were supported by the Consortium on Individual Development (CID), which is funded through the Gravitation program of the Dutch Ministry of Education, Culture, and Science and Netherlands Organization for Scientific Research (project #024.001.003). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.