Evaluating the neuropeptide-social cognition link in ageing: the mediating role of basic cognitive skills

Age Differences in Mental State Inference of Sarcasm: Contributions of Facial Emotion Recognition and Cognitive Performance

OBJECTIVES

Older age is associated with poorer ability to accurately infer mental states, but some mental states are more complex than others. Sarcasm is a complex mental state because the literal and intended meaning of a speaker's words are in opposition. Individuals must rely on additional cues (e.g., facial expressions, intonation) for accurate inference. We hypothesized that understanding of sarcastic versus sincere exchanges would be more sensitive to age-related difficulty in mental state understanding.

METHODS

We examined accuracy at identifying sarcasm among 263 adults (ages 18-90 years) using videos of social interactions in The Awareness of Social Inference Test. Hypotheses were tested using a logistic linear mixed effects model predicting correct/incorrect trial-level responses. To characterize why sarcasm differed with age, we measured 2 abilities commonly implicated in mental state understanding: facial emotion recognition and cognitive performance.

RESULTS

Sarcasm understanding declined with age, whereas understanding of sincere exchanges did not. Both better emotion recognition and cognitive performance related to better understanding of sarcastic but not sincere exchanges. Only cognitive performance showed an age-related effect such that the cognitive performance among the oldest participants facilitated their understanding of both sarcastic and sincere exchanges.

DISCUSSION

We showed that individual variation related to age and social and cognitive performance is more pronounced when the use of multiple mental state cues is more (sarcasm) or less (sincerity) necessary for accurate understanding of social interactions. Naturalistic paradigms involving multiple mental state cues can address important questions about how older adults make decisions in the real world.

Effects of chronic intranasal oxytocin on visual attention to faces vs. natural scenes in older adults

Aging is associated with changes in face processing, including desensitization to face cues like gaze direction and an attentional preference to faces with positive over negative emotional valence. A parallel line of research has shown that acute administration of oxytocin (OT) increases visual attention to social stimuli such as human faces. The current study examined effects of chronic OT administration among older adults on fixation duration to faces that varied in emotional expression, gaze direction, age, and sex. One hundred and twelve generally healthy older adults (aged 55-95 years) underwent a randomized, placebo-controlled, double-blind, between-subject clinical trial in which they self-administered either OT or placebo (P) intranasally twice a day for 4 weeks. The behavioral task involved rating the trustworthiness of faces (i.e., social stimuli) and natural scenes (i.e., non-social control stimuli) during eye tracking and was conducted before and after the intervention. Fixation duration to both the faces and the natural scenes declined from pre- to post-intervention, however this decline was less pronounced among older adults in the OT compared to the P group for faces but not scenes. Further, face cues (emotional expression, gaze direction, age, sex) did not moderate the treatment effect. This study provides first evidence that chronic intranasal OT maintains salience of social cues over time in older adults, perhaps buffering effects of habituation. These findings enhance understanding of OT effects on social cognition among older adults, and would benefit from follow up with a young adult comparison group to directly speak to specificity of observed effects to older adults and reflection of the aging process.

Does activation of oxytocinergic reward circuits postpone the decline of the aging brain?

Oxytocin supports reproduction by promoting sexual- and nursing behavior. Moreover, it stimulates reproductive organs by different avenues. Oxytocin is released to the blood from terminals of oxytocinergic neurons which project from the hypothalamus to the pituitary gland. Concomitantly, the dendrites of these neurons discharge oxytocin into neighboring areas of the hypothalamus. At this location it affects other neuroendocrine systems by autocrine and paracrine mechanisms. Moreover, sensory processing, affective functions, and reward circuits are influenced by oxytocinergic neurons that reach different sites in the brain. In addition to its facilitating impact on various aspects of reproduction, oxytocin is revealed to possess significant anti-inflammatory, restoring, and tranquilizing properties. This has been demonstrated both in many in-vivo and in-vitro studies. The oxytocin system may therefore have the capacity to alleviate detrimental physiological- and mental stress reactions. Thus, high levels of endogenous oxytocin may counteract inadequate inflammation and malfunctioning of neurons and supportive cells in the brain. A persistent low-grade inflammation increasing with age-referred to as inflammaging-may lead to a cognitive decline but may also predispose to neurodegenerative diseases such as Alzheimer's and Parkinson. Interestingly, animal studies indicate that age-related destructive processes in the body can be postponed by techniques that preserve immune- and stem cell functions in the hypothalamus. It is argued in this article that sexual activity-by its stimulating impact on the oxytocinergic activity in many regions of the brain-has the capacity to delay the onset of age-related cerebral decay. This may also postpone frailty and age-associated diseases in the body. Finally, oxytocin possesses neuroplastic properties that may be applied to expand sexual reward. The release of oxytocin may therefore be further potentiated by learning processes that involves oxytocin itself. It may therefore be profitable to raise the consciousness about the potential health benefits of sexual activity particularly among the seniors.

Single dose intranasal oxytocin administration: Data from healthy younger and older adults

Oxytocin (OT) is a neuropeptide critically involved in social cognition and behavior. Intranasal administration of OT has modulatory effects on both the brain and behavior with potential for therapeutic benefit, especially in individuals with deficits in socioemotional functions. Intranasal OT effects have been well-investigated in younger adults as well as in a variety of clinical populations (e.g., autism, schizophrenia), but there is comparatively less investigation of its function in older adults. To foster more research on OT and aging, the following dataset was made publicly available, which includes data from generally healthy younger (n = 44, age range = 18-31 years [M(SD) = 22.4 (3.0)], 48% female) and older adults (n = 43, age range = 63-81 years [M(SD)= 71.1 (5.3)], 56% female) who self-administered a single dose (24 international units) of either intranasal OT or a placebo (IND 100,860; NCT01823146). The study adopted a randomized, double-blind, between-subject design. The dataset consists of anatomical and functional resting-state neuroimaging scans acquired after nasal spray administration as well as study-specific phenotypic and demographic data. This dataset using both OT administration and neuroimaging is unique in its size and inclusion of both younger and older adults as well as women and men. This data has resulted in published work on OT modulation of cognition, behavior, and neural activation/connectivity. Open access to this data will provide the scientific community with the opportunity to investigate individual differences in the neurocognitive effects of single-dose OT in younger and older adults.

Attachment across the lifespan: Examining the intersection of pair bonding neurobiology and healthy aging

Increasing evidence suggests that intact social bonds are protective against age-related morbidity, while bond disruption and social isolation increase the risk for multiple age-related diseases. Social attachments, the enduring, selective bonds formed between individuals, are thus essential to human health. Socially monogamous species like the prairie vole (M. ochrogaster) form long-term pair bonds, allowing us to investigate the mechanisms underlying attachment and the poorly understood connection between social bonds and health. In this review, we explore several potential areas of focus emerging from data in humans and other species associating attachment and healthy aging, and evidence from prairie voles that may clarify this link. We examine gaps in our understanding of social cognition and pair bond behavior. Finally, we discuss physiologic pathways related to pair bonding that promote resilience to the processes of aging and age-related disease. Advances in the development of molecular genetic tools in monogamous species will allow us to bridge the mechanistic gaps presented and identify conserved research and therapeutic targets relevant to human health and aging.