Are older adults less generous? Age differences in emotion-related social decision making.

In social interaction, age-related differences in emotional processing may lead to varied social decision making between young and older adults. However, previous studies of social decision making have paid less attention to the interactants' emotions, leaving age differences and underlying neural mechanisms unexplored. To address this gap, the present study combined functional and structural magnetic resonance imaging, employing a modified dictator game task with recipients displaying either neutral or sad facial expressions. Behavioral results indicated that although older adults' overall allocations did not differ significantly from those of young adults, older adults' allocations showing a decrease in emotion-related generosity compared to young adults. Using representational similarity analysis, we found that older adults showed reduced neural representations of recipients' emotions and gray matter volume in the right anterior cingulate gyrus (ACC), right insula, and left dorsomedial prefrontal cortex (DMPFC) compared to young adults. More importantly, mediation analyses indicated that age influenced allocations not only through serial mediation of neural representations of the right insula and left DMPFC, but also through serial mediation of the mean gray matter volume of the right ACC and left DMPFC. This study identifies the potential neural pathways through which age affects emotion-related social decision making, advancing our understanding of older adults' social interaction behavior that they may not be less generous unless confronted with individuals with specific emotions.

Sleep Quality Modulates the Association between Dynamic Functional Network Connectivity and Cognitive Function in Healthy Older Adults.

Aging is associated with changes in sleep, brain activity, and cognitive function, as well as the association among these factors; however, the precise nature of these changes has not been elucidated. This study systematically investigated the modulatory effect of sleep on the relationship between brain functional network connectivity (FNC) and cognitive function in older adults. In total, 107 community-dwelling healthy older adults were recruited and assigned into poor sleep and good sleep groups based on the Pittsburgh Sleep Quality Index. The static functional network connectivity (sFNC), the temporal variability of dynamic FNC (dFNC) from variance (dFNC-var), and the dFNC from clustering state (dFNC-state) were calculated. Corresponding cognition-predictive models were constructed for each sleep group. dFNC but not sFNC, was able to significantly predict the cognitive function in older adults. Specifically, sleep played a modulatory role in the association between dFNC and cognitive function, with sleep-specific variations at both microscopic (i.e., specific edges) and macroscopic levels (i.e., specific states) of dFNC.

The different roles of sleep on false memory formation between young and older adults.

Aging is accompanied by an increase in the probability of false memory. However, what role sleep plays in the age effect in false memory is less understood. Our study utilized a simplified conjoint recognition (SCR)-based Deese-Roediger-McDermott (DRM) paradigm to investigate the role of sleep on false memory in young and older adults. The results showed that sleep effect in false memory was modulated by age, manifested as sleep increased young adults' falsely recognized critical lures, while it reduced older adults'. In addition, in a more fine-grained analysis, the results of multinomial processing tree (MPT) modeling further revealed that young adults were more likely to retrieve memory based on gist traces than older adults, and young adults were more susceptible to guess a probe as "old" than older adults in the sleep condition. Combined findings from the number and ratio of falsely recognized critical lures and the MPT modeling, the current study suggested that sleep might increase young adults' false memory via gist extraction, while it decreased older adults' false memory via verbatim trace consolidation. The study contributes to a comprehensive view on the age-by-sleep effect on false recognition, with the segregation of cognitive components of verbatim memory, gist memory, and response bias.

A C-type lectin with a single CRD from Onychostoma macrolepis mediates immune recognition against bacterial challenge.

C-type lectins (CTL) are a large group of pattern-recognition proteins and to play important roles in glycoprotein metabolism, multicellular integration, and immunity. Based on their overall domain structure, they can be classified as different groups that possess different physiological functions. A typical C-type lectin (named as OmLec1) was identified from the fish, Onychostoma macrolepis, an important cultured fish in China. Open reading frame of OmLec1 contains a 570 bp, encoding a protein of 189 amino acids that includes a signal peptide and a single carbohydrate-recognition domain. The phylogenetic analysis showed that OmLec1 could be grouped with C-type lectin from other fish. OmLec1 was expressed in all the tissues in our study, and the expression level was highest in liver. And its relative expression levels were significantly upregulated following infection with Aeromonas hydrophila. The recombinant OmLec1 protein (rOmLec1) could agglutinate some Gram-negative bacteria and Gram-positive bacteria in vitro in the presence of Ca2+, showing a typical Ca2+-dependent carbohydrate-binding protein. Furthermore, rOmLec1 purified from E. coli BL21 (DE3), strongly bound to LPS and PGN, as well as all tested bacteria in a Ca2+-dependent manner. These results indicate that OmLec1 plays a central role in the innate immune response and as a pattern recognition receptor that recognizes diverse pathogens among O. macrolepis.

A C-type lectin (OmCTL) in Onychostoma macrolepis: Binding ability to LPS, PGN and agglutinating activity against bacteria.

C-type lectins (CTLs) are calcium-dependent carbohydrate-binding proteins that mainly bind to carbohydrate-based or other ligands to mediate cell adhesion, recognize pathogens, and play important roles in the immune system. In the present study, a novel C-type lectin (OmCTL) isolated from Onychostoma macrolepis was investigated. The open reading frame of OmCTL comprises 468 bp, encoding a 155 amino acid polypeptide with an 18 amino acid putative signaling peptide. The predicted primary OmCTL structure contains a signal peptide, a single carbohydrate recognition domain (CRD) and an EPN/WND motif required for carbohydrate-binding specificity. Using tissue expression pattern analysis, OmCTL has been shownto be highly expressed in the liver, and is also detected in other tissues. OmCTL was significantly upregulated in the liver and spleen following infection with Aeromonas hydrophila, suggesting its involvement in immune response. The recombinant OmCTL protein (rOmCTL) agglutinated two gram-negative bacteria, Escherichia coli and A. hydrophila, in vitro in the presence of Ca2+, showing that it is a typical Ca2+-dependent carbohydrate-binding protein.Furthermore, rOmCTL purified from E. coli BL21 (DE3) strongly bound to LPS and PGN, as well as all tested bacteria in a Ca2+-independent manner. These results indicate that OmCTL plays a central role in the innate immune response and as a pattern recognition receptor that recognizes diverse pathogens among O. macrolepis.

Age-related alterations of default mode network in autobiographical memory: Recent versus remote events.

Previous studies have shown that the vividness of autobiographical memory decreases over time, and older adults often retrieve fewer details than young adults. However, the age-by-temporal distance (i.e., recent versus remote events) effect on autobiographical memory and underlying neural mechanisms are less understood. We recruited 25 young adults and 27 older adults to perform an fMRI-adapted autobiographical memory task with different temporal distances. The results showed that older adults' vividness ratings were generally higher than that of young adults, but were less sensitive to temporal distances. For neural imaging, an age-by-temporal distance effect was found in the left precuneus, manifested as young adults had more activation for recent events than for remote events, whereas no temporal distance effect was found in older adults. Interestingly, for older adults, the temporal distance effect was reflected by functional connectivity within the default mode network (DMN), with a stronger anterior DMN-posterior DMN coupling for remote events than for recent events, whereas no temporal distance difference on functional connectivity was found in young adults. The results suggest that older adults exhibit age-related neural differences in both activation and functional connectivity during the processing of autobiographical memory with different temporal distances, shedding new light for the understanding of the relationship between the DMN, autobiographical memory, and aging.

[Effect of acupuncture at pericardium points of amplitude of low frequency fluctuations of healthy people in resting state functional magnetic resonance imaging].

OBJECTIVE: To observe the effect of acupuncture at the whole points of Hand Jueyin pericardium meridian on the amplitude of low frequency fluctuations (ALFF) of healthy people in resting state (R1) functional magnetic resonance imaging (fMRI). METHODS: Totally 16 healthy subjects received structure scan of T1 and T2. Then two fMRI scans were conducted for each participant. fMRI included the resting-state scan (R1; the scanning time was 8 min 6 s), the stimulating-acupoint scan (AP; the scanning time was 8 min 6 s). fMRI data acquisition from structure scanning and function scanning were processed with format conversion and statistical analysis. RESULTS: Under R1 state, brain regions with activated ALFF signals included bilateral superior frontal gyrus, medial frontal gyrus, middle occipital gyrus, precuneus, superior temporal gyrus, and cingulate gyrus. Under the AP state, brain regions with activated ALFF signals were bilateral superior frontal gyrus, medial frontal gyrus, middle temporal gyrus, left fusiform gyrus, precuneus, posterior cingulate, and declivis. Compared with R1 state, obvious difference of ALFF signal areas of the brain caused by acupuncture at pericardium were: bilateral cuneus, precuneus, left posterior cingulate gyrus, right middle occipital gyrus, and right occipital lingual gyrus. CONCLUSION: Acupuncture at the whole points of Hand Jueyin pericardium meridian could significantly change inherent activity states of the cerebral cortex, especially in bilateral superior frontal gyrus, medial frontal gyrus, and precuneus.

Capturing amplitude changes of low-frequency fluctuations in functional magnetic resonance imaging signal: a pilot acupuncture study on NeiGuan (PC6).

OBJECTIVES: This study aims to examine amplitude changes of low-frequency oscillations (fALFF) in the blood-oxygen level-dependent (BOLD) signal associated with acupuncture on NeiGuan (PC6). EXPERIMENTAL DESIGN: Ten (10) healthy adults participated in a functional magnetic resonance imaging (i.e., nuclear medicine; fMRI) study. During the brain-imaging procedure, the participants were instructed to lie quietly; they did not perform any cognitive task. MAIN OUTCOME MEASURES: Three (3) fMRI scans were conducted for each participant: a first resting-state scan (R1), a stimulating-acupoint scan (AP), and a second resting-state scan (R2) after AP. Individual fALFF maps were calculated for each scan. RESULTS: During R1, consistent with previous studies, the default network regions showed significantly detectable fALFF amplitudes. Acupuncture on PC6 increased fALFF amplitudes within the anterior cingulate cortex (ACC), occipital fusiform gyrus, posterior cingulate cortex, and precuneus (PCC/PCU). In contrast, during R2, fALFF within PCC is still significantly higher than R1 while ACC and cerebellum showed decreased fALFF. CONCLUSIONS: These findings imply that stimulating PC6 can change the amplitude of the intrinsic cortical activity of the brain. In particular, a continuous and temporally consistent effect of acupuncture within PCC not the common brain circuit of pain including ACC and cerebellum was observed. Considering the cognitive functions and deficits of the relevant areas in mild cognitive impairment and Alzheimer disease, acupuncture on PC6 could potentially affect both psychiatric and neurological disorders. Thus, stimulating PC6 may be a candidate method for improving cognitive impairment.

[Investigation on the changes of dependent signal on the amplitude of low frequency fluctuations at blood oxygen level in brain after acupuncture Neiguan (PC 6)].

OBJECTIVE: To investigate the relationship of the acupoint and its functional location in the brain. METHODS: Ten healthy participants were examined with the resting state functional magnetic resonance imaging (fM-RI). The scanning includes the resting state 1 (R 1), acupuncture stimulating (AP) Neiguan (PC 6) and the resting state 2 (R 2). All data were analyzed with the amplitude of low frequency fluctuations (ALFF). RESULTS: 1) During the R1, the regions with active signal on the ALFF contained bilateral superior frontal gyrus, medial frontal gyrus and some part of cerebellum (including right declive, culme, tonsil and left uvula), as well as left precuneus, right superiour temporal gyrus. 2) As for AP, the active regions with higher ALFF were bilateral superior frontal gyrus and right cuneus, as well as left middle frontal gyrus, declivis and right semi-lunar lobule. 3) The main difference on ALFF between R1 and AP appeared within bilateral cingulated gyrus and declivis, left lingualgurus, and cuneus, as well as right precuneus, fusiform gyrus, superior frontal gyrus, medial frontal gyrus and superior temporal gyrus, etc. CONCLUSION: After acupuncture stimulating the left Neiguan (PC 6), the active regions on ALFF are detected on bilateral cingulated gyrus, right superior frontal gyrus and medial frontal gyrus, as well as bilateral declivis and left lingual gurus, etc. These regions have the close relationship with the mental disorder and nervous diseases, which might be the possible neural mechanism of acupuncture stimulating Neiguan (PC 6) for treating some of related mental disorder and nervous diseases.