Object recognition memory and the rodent hippocampus
- 1Department of Psychiatry, University of California, La Jolla, California 92093, USA;
- 2Department of Psychology, Concordia University, Montreal, Quebec H4B 1R6, Canada;
- 3Veterans Affairs Medical Center, San Diego, California 92161, USA;
- 4Department of Neurosciences, University of California, La Jolla, California 92093, USA;
- 5Department of Psychology, University of California, La Jolla, California 92093, USA
Abstract
In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR task. Rats received 12 5-min exposures to two identical objects and then received either bilateral lesions of the hippocampus or sham surgery 1 d, 4 wk, or 8 wk after the final exposure. On a retention test 2 wk after surgery, the 1-d and 4-wk hippocampal lesion groups exhibited impaired object recognition memory. In contrast, the 8-wk hippocampal lesion group performed similarly to controls, and both groups exhibited a preference for the novel object. These same rats were then given four postoperative tests using unique object pairs and a 3-h delay between the exposure phase and the test phase. Hippocampal lesions produced moderate and reliable memory impairment. The results suggest that the hippocampus is important for object recognition memory.
Footnotes
-
↵6 Corresponding author.
E-mail reclark{at}ucsd.edu; fax (858) 534-1569.
-
Article is online at http://www.learnmem.org/cgi/doi/10.1101/lm.1650110.
-
- Received September 28, 2009.
- Accepted October 5, 2009.
