The role of the dentate gyrus, CA3a,b, and CA3c for detecting spatial and environmental novelty
Article first published online: 23 JUL 2008
Copyright © 2008 Wiley-Liss, Inc.
Volume 18, Issue 10, pages 1064–1073, October 2008
How to Cite
Hunsaker, M. R., Rosenberg, J. S. and Kesner, R. P. (2008), The role of the dentate gyrus, CA3a,b, and CA3c for detecting spatial and environmental novelty. Hippocampus, 18: 1064–1073. doi: 10.1002/hipo.20464
- Issue published online: 18 SEP 2008
- Article first published online: 23 JUL 2008
- Manuscript Accepted: 14 MAY 2008
- NIH. Grant Number: R01MH065314
- dentate gyrus;
- environmental geometry;
- metric relationships
It has been suggested that the dentate gyrus (DG) and CA3 cooperate to efficiently process spatial information. The DG has been proposed to be important for fine spatial discrimination, and the CA3 has been proposed to mediate larger scale spatial information processing. To evaluate the roles of the DG and CA3a,b for spatial processing, we developed a task that measures responses to either overall environmental novelty or a response to more subtle changes within the environment. Animals with lesions to the DG showed impaired novelty detection for both environment as well as smaller changes in the environment, whereas animals with lesions to CA3a,b showed no such deficits. A closer look at the lesions suggested that the CA3 lesions included only CA3a and CA3b, but spared CA3c. To test the role of the spared CA3c region, animals with selective lesions to CA3c that spared CA3a,b were run on the same task and showed an intermediate pattern of deficits. These results suggest that the DG is critical for spatial information processing. These data also suggest that CA3 is a heterogeneous structure, with CA3c lesioned animals showing greater spatial processing deficits than CA3a,b lesioned animals. These findings extend our knowledge of hippocampal function and need to be accounted for in future computational models. © 2008 Wiley-Liss, Inc.