Plasma oxytocin is related to lower cardiovascular and sympathetic reactivity to stress

In addition to known reproductive and social affiliation functions, oxytocin (OT) has been identified as a cardiovascular hormone. OT synthesis and receptors are found in cardiac and vascular tissue. Animal studies suggest that OT activates an ‘anti-stress’ response that reduces cardiovascular and neuroendocrine stress reactivity. We tested 28 early postpartum mothers, obtaining multiple blood samples for OT, the sympathetic marker, norepinephrine (NE), and the lactation hormone, prolactin, while monitoring their cardiovascular responses to two stressors: public speaking and forehead cold pressor. Although plasma OT did not increase reliably from pre-stress levels during stressors, greater overall OT level was related to greater vasodilation and cardiac stroke volume responses to both tasks, to reduction in heart rate to the cold pressor, as well as to lower plasma NE and higher prolactin levels. In contrast, higher NE was linked to increases in heart rate and decreases in stroke volume. These data support a cardioprotective role for OT, which may influence the magnitude and hemodynamic determinants of cardiovascular stress responses

Thalamocortical functional connectivity and behavioral disruptions in neonates with prenatal cocaine exposure

Prenatal cocaine exposure (PCE) affects neurobehavioral development, however, disentangling direct drug-related mechanisms from contextual effects (e.g., socioeconomic status) has proven challenging in humans. The effects of environmental confounds are minimal immediately after birth thus we aimed to delineate neurobehavioral correlates of PCE in a large cohort of neonates (2–6 weeks of age, N = 152) with and without drug exposure using resting state functional magnetic resonance imaging (rsfMRI) and developmental assessments at 3 months with the Bayley Scales of Infant & Toddler Development, 3rd edition. The cohort included healthy controls and neonates with similar poly-drug exposure ± cocaine. We focused on the thalamus given its critical importance in early brain development and its unique positioning in the dopamine system. Our results revealed PCE-related hyper-connectivity between the thalamus and frontal regions and a drug-common hypo-connective signature between the thalamus and motor-related regions. PCE-specific neonatal thalamo-frontal connectivity was inversely related to cognitive and fine motor scores and thalamo-motor connectivity showed a positive relationship with composite (gross plus fine) motor scores. Finally, cocaine by selective-serotonin-reuptake-inhibitor (SSRI) interactions were detected, suggesting the combined use of these drugs during pregnancy could have additional consequences on fetal development. Overall, our findings provide the first delineation of PCE-related disruptions of thalamocortical functional connectivity, neurobehavioral correlations, and drug-drug interactions during infancy

Neural Responses to Infants linked with Behavioral Interactions and Testosterone in Fathers

Few fMRI studies have investigated the brain-behavioral basis of parenting in human fathers. Ten fathers were videotaped and gave salivary testosterone samples while interacting with their 2–4 month old infants, and viewed video clips of their own infant and an unfamiliar age-, ethnicityand sex-matched other infant during an fMRI protocol. Infant stimuli activated a network of prefrontal and subcortical brain regions. Furthermore, a subset of these regions activated significantly more to own (OWN) than other (OTHER) infants. Finally, neural responses to OWN versus OTHER were linked with paternal sensitivity, paternal reciprocity, and testosterone. In sum, our results provide a novel perspective on the links between brain, behavior, and hormones in fathers

Association Between Maternal Mood and Oxytocin Response to Breastfeeding

Postpartum depression is associated with reduced breastfeeding duration. We previously hypothesized that shared neuroendocrine mechanisms underlie this association. We sought to measure the association between maternal mood and neuroendocrine response to breastfeeding

An investigation of plasma and salivary oxytocin responses in breast- and formula-feeding mothers of infants

Oxytocin (OT) is a peptide increasingly studied in relation to human social interactions, affiliation, and clinical disorders. Studies are constrained by use of invasive blood draws and would benefit from a reliable salivary OT assay. Our goals were to examine feasibility of salivary OT measurement, compare salivary to plasma OT responses in 12 breast- and 8 formula-feeding mothers, and assess the degree of correlation between plasma and salivary OT. Using a commercial EIA kit, we measured OT in 5 saliva and 7 plasma samples in a protocol designed to elicit changes in OT (Rest, Infant Interaction, Stress, Feeding). Breast-feeders had higher OT levels than formula-feeders across all conditions in plasma (+36%) and saliva (+23%). OT levels and ranges were similar in saliva and plasma, with slightly greater variance in saliva. Concurrently sampled plasma and salivary OT were correlated at end of Baseline Rest (r = +.59, p = .022) and Post-Stress Recovery (r = +.59, p = .025). These data suggest that salivary OT assay is feasible, and will be of value where plasma samples are not possible. Validation with larger samples is needed

Does Self-Compassion Protect Adolescents from Stress?

The aim of this study was to determine whether adolescents who were high in self-compassion self-reported different levels of emotional wellbeing than adolescents who were low in self-compassion, and to determine whether those high in self-compassion responded differently under a lab social stressor than those low in self-compassion. In a lab setting, participants (age 13–18; n = 28) completed the Trier Social Stress Test (TSST) and physiological stress was assessed via salivary cortisol, heart rate, blood pressure, and heart rate variability at baseline, during the TSST, and during recovery. After completing the lab protocol, an email was sent to participants that provided a link to an online survey which was composed of emotional wellbeing measures including perceived stress, life satisfaction, positive and negative affect. After conducting repeated measure ANOVAS to determine that the TSST induced a significant stress response, the sample was split at the median of self-compassion. T tests were conducted to determine meaningful differences (Hedges’ g > .20) between the groups. Findings indicated that those in the high self-compassion group (≥the median) self-reported greater emotional wellbeing than those in the low self-compassion group (<the median). Overall, those in the high self-compassion group also had a lower physiologic stress response when exposed to the TSST than those in the low self-compassion group. Regression analyses were also conducted; baseline self-compassion predicted self-reported emotional wellbeing, but did not predict physiological response to the TSST. Findings support the potential buffering effect that self-compassion may have in protecting adolescents from social stressors; yet more research needs to be conducted in larger samples to confirm and replicate these findings

Ethnicity is associated with alterations in oxytocin relationships to pain sensitivity in women

It is well established that African Americans (AA) experience greater pain associated with a variety of clinical conditions, and greater pain sensitivity to experimental pain tasks relative to non-Hispanic Whites (W). Notably, African Americans do not show the same relationships involving endogenous pain regulatory mechanisms and pain sensitivity documented in Caucasians, including positive associations between blood pressure, norepinephrine, cortisol and greater pain tolerance

Oxytocin, Cortisol, and Cognitive Control During Acute and Naturalistic Stress

Although stress is a strong risk factor for poor health, especially for women, it remains unclear how stress affects the key neurohormones cortisol and oxytocin, which influence stress-related risk and resilience. Whereas cortisol mediates energy mobilization during stress, oxytocin has anti-inflammatory, anxiolytic, and analgesic effects that support social connection and survival across the lifespan. However, how these neurohormones interrelate and are associated with cognitive control of emotional information during stress remains unclear. To address these issues, we recruited 37 college-aged women (Mage = 19.19, SD = 1.58) and randomly assigned each to a one-hour experimental session consisting of either an acute stress (emotionally stressful video) or control (non-stressful video) condition in a cross-sectional manner across the semester. Salivary cortisol and oxytocin samples were collected at baseline and after the video, at which point participants also completed measures assessing affect and an emotional Stroop task. As hypothesized, the emotional stressor induced negative emotions that were associated with significant elevations in cortisol and faster Stroop reaction times. Moreover, higher baseline oxytocin predicted greater positive affect after the stressor and also better cognitive accuracy on the Stroop. Analyses examining the naturalistic stress effects revealed that basal oxytocin levels rose steeply three weeks before the semester’s end, followed by rising cortisol levels one week later, with both neurohormones remaining elevated through the very stressful final exam period. Considered together, these data suggest that women’s collective experiences of stress may be potentially buffered by a synchronous oxytocin surge that enhances cognitive accuracy and reduces stress “when the going gets tough”

Maternal Neuroendocrine Serum Levels in Exclusively Breastfeeding Mothers

Background: Low milk supply is a common cause of early weaning, and supply issues are associated with dysregulation of thyroid function and prolactin. However, hormone levels compatible with successful breastfeeding are not well defined, limiting interpretation of clinical lab results. In this study we sought to quantify ranges for thyroid-stimulating hormone (TSH), free thyroxine (T4), total T4, and prolactin in a cohort of exclusively breastfeeding women

Development of Translational Methods in Spectral Analysis of Human Infant Crying and Rat Pup Ultrasonic Vocalizations for Early Neurobehavioral Assessment

The purpose of this article is to describe the development of translational methods by which spectrum analysis of human infant crying and rat pup ultrasonic vocalizations (USVs) can be used to assess potentially adverse effects of various prenatal conditions on early neurobehavioral development. The study of human infant crying has resulted in a rich set of measures that has long been used to assess early neurobehavioral insult due to non-optimal prenatal environments, even among seemingly healthy newborn and young infants. In another domain of study, the analysis of rat put USVs has been conducted via paradigms that allow for better experimental control over correlated prenatal conditions that may confound findings and conclusions regarding the effects of specific prenatal experiences. The development of translational methods by which cry vocalizations of both species can be analyzed may provide the opportunity for findings from the two approaches of inquiry to inform one another through their respective strengths. To this end, we present an enhanced taxonomy of a novel set of common measures of cry vocalizations of both human infants and rat pups based on a conceptual framework that emphasizes infant crying as a graded and dynamic acoustic signal. This set includes latency to vocalization onset, duration and repetition rate of expiratory components, duration of inter-vocalization-intervals and spectral features of the sound, including the frequency and amplitude of the fundamental and dominant frequencies. We also present a new set of classifications of rat pup USV waveforms that include qualitative shifts in fundamental frequency, similar to the presence of qualitative shifts in fundamental frequency that have previously been related to insults to neurobehavioral integrity in human infants. Challenges to the development of translational analyses, including the use of different terminologies, methods of recording, and spectral analyses are discussed, as well as descriptions of automated processes, software solutions, and pitfalls