Shared vivid remembering: age-related differences in across-participants similarity of neural representations during encoding and retrieval

ABSTRACT

Recent advances in multivariate neuroimaging analyses have made possible the examination of the similarity of the neural patterns of activations measured across participants, but it has not been investigated yet whether such measure is age-sensitive. Here, in the scanner, young and older participants viewed scene pictures associated with labels. At test, participants were presented with the labels and were asked to recollect the associated picture. We used Pattern Similarity Analyses by which we compared patterns of neural activation during the encoding or the remembering of each picture of one participant with the averaged pattern of activation across the remaining participants. Results revealed that across-participants neural similarity was higher in young than in older adults in distributed occipital, temporal and parietal areas during encoding and retrieval. These findings demonstrate that an age-related reduction in specificity of neural activation is also evident when the similarity of neural representations is examined across participants.

KEYWORDS:

• Episodic memory
• aging
• pattern similarity
• shared memory
• fMRI

Acknowledgments

The authors wish to thank Nikita Beliy for his help with the Matlab codes and two Reviewers whose comments were very helpful in improving the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here.

Notes

1. It was not possible to examine age-differences across different memory vividness levels in the present study because older adults mostly expressed their subjective vividness ratings by using the maximum level of the scale (i.e., ratings of 3) and therefore did not have enough trials in lower vividness levels.

2. Note that similar results as those reported here were obtained when examining across-participants neural similarity on hit trials (i.e., trials that received vividness ratings of 1, 2 or 3, see the supplementary material section).

Additional information

Funding

This work was supported by the Fund for Scientific Research (FRS-FNRS) under grant number (F 06/ 40/05 – FRESH/FC) attributed to AF. ED and CB are respectively Postdoctoral Researcher and Senior Research Associate at the FRS-FNRS.