Related Experiment Video
Updated: Jun 6, 2026
Novel Object Recognition Test for the Investigation of Learning and Memory in Mice
Published on: August 30, 2017
Novel object recognition memory: measurement issues and effects of MDMA self-administration following short
Susan Schenk1, David N Harper, Jennifer Do
1School of Psychology, Victoria University of Wellington, Wellington, New Zealand. susan.schenk@vuw.ac.nz
Abstract:
The present study was undertaken to examine effects of self-administered MDMA on novel object exploration (NOR) memory. Self-administration was conducted during daily 2 h tests that continued until a total of 165 mg/kg was self-administered (range = 13-41 days for individual rats). Control rats were placed in the self-administration boxes during daily sessions but did not receive any drug. One or 10 weeks following the last self-administration session, memory was assessed using a standard NOR task. When exploration time was used as the dependent measure for the control rats, there was no consistent pattern of change as a function of inter-trial interval (ITI) and exploration times failed to reveal decay in the function relating exploration to ITI. When number of approaches was examined as a function of ITI, however, there was a preference for the novel object following the short ITIs (1-15 min) and the function relating preference to ITI decayed with longer ITIs. When tested 7 days following the last self-administration session, rats that self-administered MDMA failed to demonstrate NOR even following the shortest ITI of 1 min. The data support the idea that MDMA self-administration produces cognitive deficits and are consistent with the idea that attentional processes become disrupted. There was, however, recovery of NOR memory when rats were tested following an extended drug-free period of 70 days. Thus, the deficits are transient and recovery was apparent.
Insights
Self-administering MDMA (3,4-methylenedioxymethamphetamine) impairs novel object recognition memory in rats. These cognitive deficits are temporary, with memory function recovering after an extended drug-free period.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Pharmacology
Background:
- MDMA (3,4-methylenedioxymethamphetamine) is a recreational drug with known psychoactive effects.
- Understanding the long-term cognitive consequences of MDMA use is crucial for public health.
- Previous research suggests potential neurotoxic effects of MDMA.
Purpose of the Study:
- To investigate the impact of self-administered MDMA on novel object exploration (NOR) memory in rats.
- To determine if MDMA self-administration leads to lasting cognitive deficits.
- To assess the potential for recovery of memory function after cessation of MDMA use.
Main Methods:
- Rats self-administered MDMA (165 mg/kg total dose) over several weeks.
- Control rats received no drug.
- Memory was assessed using the NOR task at 1 or 10 weeks post-drug exposure, with varying inter-trial intervals (ITIs).
Main Results:
- Rats self-administering MDMA showed significant deficits in NOR memory 7 days after the last session, even with short ITIs.
- Exploration time and preference for novel objects were impaired in MDMA-exposed rats.
- Memory function recovered when rats were tested 70 days after the last MDMA self-administration session.
Conclusions:
- MDMA self-administration induces transient cognitive deficits, specifically impacting novel object recognition memory.
- The findings suggest that MDMA disrupts attentional processes.
- Complete recovery of NOR memory is possible after a prolonged period without drug exposure.
