Self-initiated learning reveals memory performance and electrophysiological differences between younger, older and older adults with relative memory impairment

Still Wanting to Win: Reward System Stability in Healthy Aging

Healthy aging is accompanied by multi-faceted changes. Especially within the brain, healthy aging exerts substantial impetus on core parts of cognitive and motivational networks. Rewards comprise basic needs, such as food, sleep, and social contact. Thus, a functionally intact reward system remains indispensable for elderly people to cope with everyday life and adapt to their changing environment. Research shows that reward system function is better preserved in the elderly than most cognitive functions. To investigate the compensatory mechanisms providing reward system stability in aging, we employed a well-established reward paradigm (Monetary Incentive Delay Task) in groups of young and old participants while undergoing EEG measurement. As a new approach, we applied EEG connectivity analyses to assess cortical reward-related network connectivity. At the behavioral level, our results confirm that the function of the reward system is preserved in old age. The mechanisms identified for maintaining reward system function in old age do not fit into previously described models of cognitive aging. Overall, older adults exhibit lower reward-related connectivity modulation, higher reliance on posterior and right-lateralized brain areas than younger adults, and connectivity modulation in the opposite direction than younger adults, with usually greater connectivity during non-reward compared to reward conditions. We believe that the reward system has unique compensatory mechanisms distinct from other cognitive functions, probably due to its etymologically very early origin. In summary, this study provides important new insights into cortical reward network connectivity in healthy aging.

Deficits in facial emotional valence processing in older people with subjective memory complaints: Behavioral and electrophysiological evidence

Subjective memory complaints (SMCs), which occur in the absence of clinical memory deficits, may precede mild cognitive impairment (MCI) or Alzheimer's disease (AD). Some studies have reported a deficit in facial emotion processing in people with MCI or AD. However, it is unclear whether this deficit is also present in older people with SMCs. The present study used behavioral measurements and event-related potentials (ERPs) to investigate the facial emotion processing of 41 older people with SMCs and 38 without SMCs. The task contained 204 images displaying facial emotions (positive, negative, and neutral). In terms of behavior, our results showed that participants with SMCs were slower and less accurate than controls. In terms of ERPs, the N170 latency was longer in men with SMCs than in controls, whereas no differences were observed between groups in the P300 and late positive potential (LPP) latencies or amplitudes. Moreover, in participants with SMCs, higher P300 and LPP amplitudes were related to better performance on working memory, psychomotor speed, and attention. Additionally, women were faster and more accurate than men on the facial emotion-processing task. In sum, these results suggest that older people with SMCs may have deficits in the processing of facial expressions of emotion. However, this deficit seems to affect the structural encoding of faces, rather than the late stages of processing.