Worry Modifies the Relationship between Locus Coeruleus Activity and Emotional Mnemonic Discrimination.

Linda H G Pagen,Frans R J Verhey,Benedikt A Poser,Martin P J Van Boxtel,Heidi I L Jacobs,Nikos Priovoulos,Roy W E Van Hooren

doi:10.3390/brainsci12030381

Abstract

Background: The locus coeruleus (LC) plays a critical role in modulating emotional memory performance via widespread connections to the medial temporal lobe (MTL). Interestingly, both the LC and MTL are affected during aging. Therefore, we aimed to investigate whether worry during cognitive aging changes the relationship between memory performance and the neural activity patterns during an emotional memory task. Methods: Twenty-eight participants aged 60–83 years from the Maastricht Aging study conducted an emotional mnemonic discrimination task during a 7T fMRI-scan. We performed a robust multiple linear regression to examine the association between worry and mnemonic memory performance under different levels of arousal. Subsequently, we examined if worry modifies the relationship between neuronal activity and mnemonic memory performance. Results: We observed that under low arousal, only participants with low compared to high levels of worry benefitted from additional LC activity. Under high arousal, additional LC activity was associated with lower mnemonic memory performance. Conclusion: Our results suggest there might be an optimal involvement of the NA-system for optimal memory discrimination performance, as we observed that under low levels of worry and with lower levels of arousal, higher LC activity might be needed to achieve similar levels of optimal memory performance as achieved under higher arousal when LC activity remained lower.

Highlights

Ample studies demonstrated that negative emotional arousal and the associated release of noradrenaline (NA) enhance memory performance [1–4]
A memory process that relies on both the medial temporal lobe (MTL) structures and the locus coeruleus (LC), is well suited to investigate the modulation of arousal on memory [4,14,15]
Investigating whether arousal modulates the association between worry and memory performance for the contrasts higharousing negatively valanced (HA) Hits > low-arousing neutral valanced (LA) Hits (Table 3), we found that lower LC activity was associated with higher Hits during HA only for participants with low levels of worry compared to those with high levels of worry

Summary

Introduction

Ample studies demonstrated that negative emotional arousal and the associated release of noradrenaline (NA) enhance memory performance [1–4]. The LC is believed to play a critical role in modulating memory performance through its widespread connections, and in particular through the effect of NA on adrenergic receptors in the medial temporal lobe [7–10] Both the LC and the medial temporal lobe (MTL) play an important role in both memory performance and emotional regulation, two processes that are well known to be affected during aging [2,11–13]. The locus coeruleus (LC) plays a critical role in modulating emotional memory performance via widespread connections to the medial temporal lobe (MTL). Both the LC and MTL are affected during aging. Conclusion: Our results suggest there might be an optimal involvement of the NA-system for optimal memory discrimination performance, as we observed that under low levels of worry and with lower levels of arousal, higher LC activity might be needed to achieve similar levels of optimal memory performance as achieved under higher arousal when LC activity remained lower

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