Effects of Long-Chain Polyunsaturated Fatty Acids in Combination with Lutein and Zeaxanthin on Episodic Memory in Healthy Older Adults.

Arachidonic acid (ARA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), which are long-chain polyunsaturated fatty acids (LCPUFAs), as well as lutein (L) and zeaxanthin (Z), can potentially improve brain function. However, the effect of a combination of these components (LCPUFAs + LZ) on memory function in healthy older individuals remains unclear. This study aimed to determine if LCPUFAs + LZ-supplemented food could improve memory function. Exploratory and confirmatory trials (Trials 1 and 2, respectively) were conducted in healthy older Japanese individuals with memory complaints. We conducted randomized, double-blind, placebo-controlled, parallel-group trials. Participants were randomly allocated to two groups: placebo or LCPUFAs + LZ. LCPUFAs + LZ participants were provided with supplements containing ARA, DHA, EPA, L, and Z for 24 weeks in Trial 1 and 12 weeks in Trial 2. Memory functions were evaluated using Cognitrax before and after each trial. Combined analyses were performed for subgroups of participants with cognitive decline in Trials 1 and 2. The results showed that supplementation with LCPUFAs + LZ did not significantly affect memory function in healthy, non-demented, older individuals with memory complaints whereas it improved memory function in healthy, non-demented, older individuals with cognitive decline.

Effects of combining exercise with long-chain polyunsaturated fatty acid supplementation on cognitive function in the elderly: a randomised controlled trial.

Multifactorial lifestyle intervention is known to be more effective for ameliorating cognitive decline than single factor intervention; however, the effects of combining exercise with long-chain polyunsaturated fatty acids (LCPUFA) on the elderlies' cognitive function remain unclear. We conducted a randomised, single-masked placebo-controlled trial in non-demented elderly Japanese individuals. Participants were randomly allocated to the exercise with LCPUFA, placebo, or no exercise with placebo (control) groups. Participants in the exercise groups performed 150 min of exercise per week, comprised resistance and aerobic training, for 24 weeks with supplements of either LCPUFA (docosahexaenoic acid, 300 mg/day; eicosapentaenoic acid, 100 mg/day; arachidonic acid, 120 mg/day) or placebo. Cognitive functions were evaluated by neuropsychological tests prior to and following the intervention. The per-protocol set analysis (n = 76) revealed no significant differences between the exercise and the control groups in changes of neuropsychological tests. Subgroup analysis for participants with low skeletal muscle mass index (SMI) corresponding to sarcopenia cut-off value showed changes in selective attention, while working memory in the exercise with LCPUFA group was better than in the control group. These findings suggest that exercise with LCPUFA supplementation potentially improves attention and working memory in the elderly with low SMI.

[Time and Self in Episodic Memory and Confabulation].

Confabulation is defined as the production of narrative descriptions of events that never happened, and is often observed in amnesia with basal forebrain lesions. However, little is known about the possible mechanisms related to confabulation. In this review article, we summarized previous neuropsychological and neuroimaging studies associated with confabulation, and proposed a hypothetical mechanism of confabulation. Previous studies have demonstrated that amnesic patients with confabulation after basal forebrain damage are impaired in the processing of time-related information in episodic memory and that activation of this region is significant during the processing of time-related information in episodic memory. In addition, confabulating patients with basal forebrain lesions extending to the medial prefrontal cortex (mPFC), medial temporal, and thalamic regions are likely to show significant disturbances in age-awareness and significant false memories in personally experienced events. Given the importance of the mPFC in the self-referential process and of the hippocampus in the integration of episodic components, the basal forebrain region could play an important role in orienting the self in time by acting as an interface between the mPFC and the hippocampus. Confabulation in basal forebrain amnesia could be caused by a decline of the time-self interaction.

Orbitofrontal and hippocampal contributions to memory for face-name associations: the rewarding power of a smile.

Memory processes can be enhanced by reward, and social signals such a smiling face can be rewarding to humans. Using event-related functional MRI (fMRI), we investigated the rewarding effect of a simple smile during the encoding and retrieval of face-name associations. During encoding, participants viewed smiling or neutral faces, each paired with a name, and during retrieval, only names were presented, and participants retrieved the associated facial expressions. Successful memory activity of face-name associations was identified by comparing remembered vs. forgotten trials during both encoding and retrieval, and the effect of a smile was identified by comparing successful memory trials for smiling vs. neutral faces. The study yielded three main findings. First, behavioral results showed that the retrieval of face-name associations was more accurate and faster for smiling than neutral faces. Second, the orbitofrontal cortex and the hippocampus showed successful encoding and retrieval activations, which were greater for smiling than neutral faces. Third, functional connectivity between the orbitofrontal cortex and the hippocampus during successful encoding and retrieval was stronger for smiling than neutral faces. As a part of the reward system, the orbitofrontal cortex may modulate memory processes of face-name associations mediated by the hippocampus. Interestingly, the effect of a smile during retrieval was found even though only names were presented as retrieval cues, suggesting that the effect was mediated by face imagery. Taken together, the results demonstrate how rewarding social signals from a smiling face can enhance relational memory for face-name associations.