Work

Changes in Task‐evoked Pupil Dilation during Emotional Memory as a Marker of Noradrenergic Function in Healthy Aging and MCI

Year: 2025

Type: article

Abstract: BACKGROUND: Improved memory for negative events is supported by the locus coeruleus-noradrenergic (LC-NA) system. As the LC is one of the first structures exhibiting tau pathologies in AD, in vivo markers for structural and functional changes in the LC are required. We used pupil dilation (PD) as a non-exclusive and indirect but easy and non-invasive way to acquire a measure of LC-NA activity. We investigated whether PD can serve as a marker of alteration in noradrenergic function in mild cognitive impairment (MCI) during emotional memory. METHOD: The emotional memory task was completed by 83 participants (28 younger adults (YAs), 25 older adults (OAs), and 30 patients with MCI) during eye-tracking recordings. In the incidental encoding task, participants were shown a neutral or negative indoor or outdoor scene and were instructed to categorize it as either indoor or outdoor. In the immediate recognition test and the delayed recognition test (6 hours later), participants were instructed to classify the pictures as new or old. RESULT: PD was larger for emotional as compared to neutral scenes in YAs and OAs but overall increased in MCI patients, regardless of scene type, suggesting a deficiency in emotional regulation. The increase in emotional reactivity in MCI does not translate into improved emotional memory; as expected, emotional scenes were better remembered than neutral scenes, with MCI patients showing worse memory than YAs or OAs. CONCLUSION: PD can be reliably measured in patients with MCI. Moreover, changes in task-evoked PD during an emotional memory task can reveal differences between healthy aging and MCI in emotional reactivity.

Source: Alzheimer s & Dementia

DOI: 10.1002/alz70861_108410