Dorsal hippocampus involvement in delay fear conditioning depends upon the strength of the tone-footshock association
Article first published online: 27 FEB 2008
Copyright © 2008 Wiley-Liss, Inc.
Volume 18, Issue 7, pages 640–654, July 2008
How to Cite
Quinn, J. J., Wied, H. M., Ma, Q. D., Tinsley, M. R. and Fanselow, M. S. (2008), Dorsal hippocampus involvement in delay fear conditioning depends upon the strength of the tone-footshock association. Hippocampus, 18: 640–654. doi: 10.1002/hipo.20424
- Issue published online: 16 JUN 2008
- Article first published online: 27 FEB 2008
- Manuscript Accepted: 21 JAN 2008
- NIMH. Grant Number: MH62122
- Unknown funding agency. Grant Number: 5F31MH066549
The hippocampus is important for the formation of spatial, contextual, and episodic memories. For instance, lesions of the dorsal hippocampus (DH) produce demonstrable deficits in contextual fear conditioning. By contrast, it is generally agreed that the DH is not important for conditioning to a discrete cue (such as a tone or light) that is paired with footshock in a temporally contiguous fashion (delay conditioning). There are, however, some reports of hippocampus involvement in delay conditioning. The present series of experiments was designed to assess the conditions under which the hippocampus-dependent component of delay fear conditioning performance may be revealed. Here, we manipulated the number of conditioning trials and the intensity of the footshock in order to vary the strength of conditioning. The results indicate that the DH contributes to freezing performance to a delay conditioned tone when the conditioning parameters are relatively weak (few trials or low footshock intensity), but not when strong parameters are used. The results are discussed in terms of two parallel memory systems: a direct tone-footshock association that is independent of the hippocampus and a hippocampus-dependent memory for the conditioning session. © 2008 Wiley-Liss, Inc.