This article was published online on February 2, 2013. An edit was subsequently requested. This notice is included in the online and print versions to indicate that both have been corrected on 23 March 2013.
Effortful retrieval reduces hippocampal activity and impairs incidental encoding†
Version of Record online: 2 FEB 2013
Copyright © 2013 Wiley Periodicals, Inc.
Volume 23, Issue 5, pages 367–379, May 2013
How to Cite
Reas, E. T. and Brewer, J. B. (2013), Effortful retrieval reduces hippocampal activity and impairs incidental encoding. Hippocampus, 23: 367–379. doi: 10.1002/hipo.22096
- Issue online: 8 APR 2013
- Version of Record online: 2 FEB 2013
- Manuscript Accepted: 2 JAN 2013
- National Institute of Neurological Disorders and Stroke
- The General Electric Medical Foundation and the University of California, San Diego. Grant Numbers: NINDS K02, NS067427
- episodic memory;
Functional imaging studies frequently report that the hippocampus is engaged by successful episodic memory retrieval. However, considering that concurrent encoding of the background environment occurs during retrieval and influences medial temporal lobe activity, it is plausible that hippocampal encoding functions are reduced with increased attentional engagement during effortful retrieval. Expanding upon evidence that retrieval efforts suppress activity in hippocampal regions implicated in encoding, this study examines the influence of retrieval effort on encoding performance and the interactive effects of encoding and retrieval on hippocampal and neocortical activity. Functional magnetic resonance imaging was conducted while subjects performed a word recognition task with incidental picture encoding. Both lower memory strength and increased search duration were associated with encoding failure and reduced hippocampal and default network activity. Activity in the anterior hippocampus tracked encoding, which was more strongly deactivated when incidental encoding was unsuccessful. These findings highlight potential contributions from background encoding processes to hippocampal activations during neuroimaging studies of episodic memory retrieval. © 2013 Wiley Periodicals, Inc.