256 research outputs found

    Graphite/polyimide laminates with near-zero thermal expansion

    Get PDF
    Composite structures can be laminated to have very low coefficients of thermal expansion. Such structures are light and strong and have many uses where expansion or contraction with temperature change is undesirable. One application is with instruments that measure thermal expansion

    Elevated cerebrospinal fluid and blood concentrations of oxytocin following its intranasal administration in humans

    Get PDF
    There has been an unprecedented interest in the modulatory effects of intranasal oxytocin on human social cognition and behaviour, however as yet no study has actually demonstrated that this modality of administration increases concentrations of the peptide in the brain as well as blood in humans. Here using combined blood and cerebrospinal fluid (CSF) sampling in subjects receiving either 24 IU of oxytocin (n = 11) or placebo (n = 4) we have shown that oxytocin levels significantly increased in both plasma and CSF. However, whereas oxytocin plasma concentrations peaked at 15 min after intranasal administration and decreased after 75 min, CSF concentrations took up to 75 min to reach a significant level. Moreover, there was no correlation (r = <0.10) between oxytocin plasma and CSF concentrations. Together, these data provide crucial insights into the plasma and CSF kinetics of intranasally administered oxytocin

    Oxytocin's neurochemical effects in the medial prefrontal cortex underlie recovery of task-specific brain activity in autism: a randomized controlled trial

    Get PDF
    The neuropeptide oxytocin may be an effective therapeutic strategy for the currently untreatable social and communication deficits associated with autism. Our recent paper reported that oxytocin mitigated autistic behavioral deficits through the restoration of activity in the ventromedial prefrontal cortex (vmPFC), as demonstrated with functional magnetic resonance imaging (fMRI) during a socio-communication task. However, it is unknown whether oxytocin exhibited effects at the neuronal level, which was outside of the specific task examined. In the same randomized, double-blind, placebo-controlled, within-subject cross-over clinical trial in which a single dose of intranasal oxytocin (24 IU) was administered to 40 men with high-functioning autism spectrum disorder (UMIN000002241/000004393), we measured N-acetylaspartate (NAA) levels, a marker for neuronal energy demand, in the vmPFC using (1)H-magnetic resonance spectroscopy ((1)H-MRS). The differences in the NAA levels between the oxytocin and placebo sessions were associated with oxytocin-induced fMRI signal changes in the vmPFC. The oxytocin-induced increases in the fMRI signal could be predicted by the NAA differences between the oxytocin and placebo sessions (P=0.002), an effect that remained after controlling for variability in the time between the fMRI and (1)H-MRS scans (P=0.006) and the order of administration of oxytocin and placebo (P=0.001). Furthermore, path analysis showed that the NAA differences in the vmPFC triggered increases in the task-dependent fMRI signals in the vmPFC, which consequently led to improvements in the socio-communication difficulties associated with autism. The present study suggests that the beneficial effects of oxytocin are not limited to the autistic behavior elicited by our psychological task, but may generalize to other autistic behavioral problems associated with the vmPFC

    Perception of social interaction compresses subjective duration in an oxytocin-dependent manner

    Get PDF
    Communication through body gestures permeates our daily life. Efficient perception of the message therein reflects one's social cognitive competency. Here we report that such competency is manifested temporally as shortened subjective duration of social interactions: motion sequences showing agents acting communicatively are perceived to be significantly shorter in duration as compared with those acting noncommunicatively. The strength of this effect is negatively correlated with one's autistic-like tendency. Critically, intranasal oxytocin administration restores the temporal compression effect in socially less proficient individuals, whereas the administration of atosiban, a competitive antagonist of oxytocin, diminishes the effect in socially proficient individuals. These findings indicate that perceived time, rather than being a faithful representation of physical time, is highly idiosyncratic and ingrained with one's personality trait. Moreover, they suggest that oxytocin is involved in mediating time perception of social interaction, further supporting the role of oxytocin in human social cognition

    Risk of dementia and mild cognitive impairment in older people with subjective memory complaints: meta-analysis

    Get PDF
    Objective: To investigate whether people with subjective memory complaints (SMC) but no objective deficits are at increased risk of developing mild cognitive impairment (MCI) and dementia. Method: Major electronic databases were searched till 03/2014, and a meta-analysis was conducted using inception cohort studies. Results: Across 28 studies, there were 29 723 unique individuals (14 714 with SMC and 15 009 without SMC) (mean 71.6 years) followed on average for 4.8 years through to dementia. The annual conversion rate (ACR) of SMC to dementia was 2.33% (95% CI = 1.93%–2.78%) a relative risk (RR) of 2.07 (95% CI = 1.76–2.44) compared with those without SMC (n = 15 009). From 11 studies the ACR of developing MCI was 6.67% (95% CI = 4.70–8.95%). In long-term studies over 4 years, 14.1% (9.67–19.1%) of people with SMC developed dementia and 26.6% (95% CI = 5.3–39.7) went on to develop MCI. The ACR from SMC to dementia and MCI were comparable in community and non-community settings. Conclusion: Older people with SMC but no objective complaints are twice as likely to develop dementia as individuals without SMC. Approximately 2.3% and 6.6% of older people with SMC will progress to dementia and MCI per year

    Does the oxytocin receptor polymorphism (rs2254298) confer 'vulnerability' for psychopathology or 'differential susceptibility'? insights from evolution

    Get PDF
    The diathesis-stress model of psychiatric conditions has recently been challenged by the view that it might be more accurate to speak of 'differential susceptibility' or 'plasticity' genes, rather than one-sidedly focusing on individual vulnerability. That is, the same allelic variation that predisposes to a psychiatric disorder if associated with (developmentally early) environmental adversity may lead to a better-than-average functional outcome in the same domain under thriving (or favourable) environmental conditions. Studies of polymorphic variations of the serotonin transporter gene, the monoamino-oxidase-inhibitor A coding gene or the dopamine D4 receptor gene indicate that the early environment plays a crucial role in the development of favourable versus unfavourable outcomes. Current evidence is limited, however, to establishing a link between genetic variation and behavioural phenotypes. In contrast, little is known about how plasticity may be expressed at the neuroanatomical level as a 'hard-wired' correlate of observable behaviour. The present review article seeks to further strengthen the argument in favour of the differential susceptibility theory by incorporating findings from behavioural and neuroanatomical studies in relation to genetic variation of the oxytocin receptor gene. It is suggested that polymorphic variation at the oxytocin receptor gene (rs2254298) is associated with sociability, amygdala volume and differential risk for psychiatric conditions including autism, depression and anxiety disorder, depending on the quality of early environmental experiences. Seeing genetic variation at the core of developmental plasticity can explain, in contrast to the diathesis-stress perspective, why evolution by natural selection has maintained such 'risk' alleles in the gene pool of a population

    Inhaled oxytocin increases positive social behaviors in newborn macaques

    Get PDF
    Early caregiver–infant interactions are critical for infants’ socioemotional and cognitive development. Several hormones and neuromodulators, including oxytocin, affect these interactions. Exogenous oxytocin promotes social behaviors in several species, including human and nonhuman primates. Although exogenous oxytocin increases social function in adults—including expression recognition and affiliation—it is unknown whether oxytocin can increase social interactions in infants. We hypothesized that nebulized oxytocin would increase affiliative social behaviors and such effects would be modulated by infants’ social skills, measured earlier in development. We also hypothesized that oxytocin’s effects on social behaviors may be due to its anxiolytic effects. We tested these hypotheses in a blind study by nebulizing 7- to 14-d-old macaques (n = 28) with oxytocin or saline. Following oxytocin administration, infants’ facial gesturing at a human caregiver increased, and infants’ salivary oxytocin was positively correlated with the time spent in close proximity to a caregiver. Infants’ imitative skill (measured earlier in development: 1–7 d of age) predicted oxytocin-associated increases in affiliative behaviors—lip smacking, visual attention to a caregiver, and time in close proximity to a caregiver—suggesting that infants with higher propensities for positive social interactions are more sensitive to exogenous oxytocin. Oxytocin also decreased salivary cortisol, but not stress-related behaviors (e.g., scratching), suggesting the possibility of some anxiolytic effects. To our knowledge, this study provides the first evidence that oxytocin increases positive social behaviors in newborns. This information is of critical importance for potential interventions aimed at ameliorating inadequate social behaviors in infants with higher likelihood of developing neurodevelopmental disorder
    • 

    corecore