Hippocampal involvement in retrieval of odor vs. object memories
Article first published online: 21 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
Volume 23, Issue 2, pages 122–128, February 2013
How to Cite
Lehn, H., Kjønigsen, L. J., Kjelvik, G. and Håberg, A. K. (2013), Hippocampal involvement in retrieval of odor vs. object memories. Hippocampus, 23: 122–128. doi: 10.1002/hipo.22073
- Issue published online: 23 JAN 2013
- Article first published online: 21 SEP 2012
- Manuscript Accepted: 6 AUG 2012
- The Norwegian Research Council. Grant Number: 165334
- episodic memory;
- olfactory memory;
- modality effects;
The aim of this study was to investigate the role of the human hippocampus in episodic retrieval of odors, in comparison with episodic retrieval of visual objects. Subjects encoded a set of unique odors and objects, and retrieval was tested the next day during functional magnetic resonance imaging (fMRI). Subjects were shown the names of old (studied) and new (unstudied) odors and objects, and asked to indicate which of these stimuli had been presented the previous day. The results showed that brain activation was weaker and more restricted during retrieval of odors than during retrieval of objects, which possibly reflects a general visual dominance effect. Yet, retrieval of odors and objects yielded overlapping clusters of activation the bilateral hippocampi, and the left-sided activation was specifically increased during successful retrieval (hits > correct rejections) in both modalities. Moreover, retrieval of odors uniquely activated olfactory cortical regions, likely to reflect cortical reinstatement of sensory details. Our fMRI study is the first to make a direct comparison between olfactory and visual episodic memory, and the results provide clear evidence for modality-independent functions of the hippocampus. © 2012 Wiley Periodicals, Inc.