The role of perceived negative partner behavior in daily snacking behavior: A dynamical systems approach.

Past work suggested that psychological stress, especially in the context of relationship stress, is associated with increased consumption of energy-dense food and when maintained for long periods of time, leads to adverse health consequences. Furthermore, this association is moderated by a variety of factors, including emotional over-eating style. That being said, few work utilized a dynamical system approach to understand the intraindividual and interindividual fluctuations within this process. The current study utilized a 14-day daily diary study, collected between January-March 2020, where participants reported their partner's negative relationship behavior and their own snacking behavior. A differential equation model was applied to the daily dairy data collected. Results showed that snacking behavior followed an undamped oscillator model while negative relationship behavior followed a damped coupled oscillator model. In other words, snacking behavior fluctuated around an equilibrium but was not coupled within dyadic partners. Negative relationship behavior fluctuated around an equilibrium and was amplified over time, coupled within dyadic partners. Furthermore, we found a two-fold association between negative relationship behavior and snacking: while the association between the displacement of negative relationship behavior and snacking was negative, change in negative relationship behavior and snacking were aligned. Thus, at any given time, one's snacking depends both on the amount of negative relationship behaviors one perceives and the dynamical state a dyad is engaging in (i.e., whether the negative relationship behavior is "exacerbating" or "resolving"). This former association was moderated by emotional over-eating style and the latter association was not. The current findings highlight the importance of examining dynamics within dyadic system and offers empirical and methodological insights for research in adult relationships.

Social Regulation of the Neural Threat Response Predicts Subsequent Markers of Physical Health.

OBJECTIVE: Social support has been linked to a vast range of beneficial health outcomes. However, the physiological mechanisms of social support are not well characterized. Drawing on functional magnetic resonance imaging and health-related outcome data, this study aimed to understand how neural measures of "yielding"-the reduction of brain activity during social support-moderate the link between social support and health. METHODS: We used a data set where 78 participants around the age of 24 years were exposed to the threat of shock when holding the hand of a partner. At ages 28 to 30 years, participants returned for a health visit where inflammatory activity and heart rate variability were recorded. RESULTS: Findings showed a significant interaction between dorsal anterior cingulate cortex-related yielding and perceived social support on C-reactive protein levels ( ß = -0.95, SE = 0.42, z = -2.24, p = .025, 95% confidence interval = -1.77 to -0.12). We also found a significant interaction between hypothalamus-related yielding and perceived social support on baseline heart rate variability ( ß = 0.51, SE = 0.23, z = 2.19, p = .028, 95% confidence interval = 0.05 to 0.97). CONCLUSIONS: Greater perceived social support was associated with lower C-reactive protein levels and greater baseline heart rate variability among individuals who were more likely to yield to social support in the dorsal anterior cingulate cortex and hypothalamus years earlier. The current study highlights the construct of yielding in the link between social support and physical health.

OXTR DNA methylation moderates the developmental calibration of neural reward sensitivity.

The Adaptive Calibration Model of Stress Responsivity (ACM) suggests that developmental experiences predictably tune biological systems to meet the demands of the environment. Particularly important is the calibration of reward systems. Using a longitudinal sample (N = 184) followed since adolescence, this study models the dimensions of early life stress and their effects on epigenetic modification of the oxytocin receptor gene (OXTR) and individual differences in neural response to reward anticipation. We first created a latent variable model of developmental context using measures collected when participants were 13 years old. As adults, two subsets of participants completed a reward anticipation fMRI paradigm (N = 82) and agreed to have their blood assayed for (OXTR) DNA methylation (N = 112) at two CpG sites. Three latent constructs of developmental context emerged: Neighborhood Harshness, Family Harshness, and Abuse and Disorder. Greater OXTR DNA methylation at CpG sites -924 and -934 blunted the association between greater Neighborhood Harshness and increased neural activation in caudate in anticipation of rewards. Interaction effects were also found outside of reward-related areas for all three latent constructs. Results indicate an epigenetically derived differential susceptibility model whereby high methylation coincides with decreased association between developmental environment and neural reward anticipation.

A low-rank multivariate general linear model for multi-subject fMRI data and a non-convex optimization algorithm for brain response comparison.

The focus of this paper is on evaluating brain responses to different stimuli and identifying brain regions with different responses using multi-subject, stimulus-evoked functional magnetic resonance imaging (fMRI) data. To jointly model many brain voxels' responses to designed stimuli, we present a new low-rank multivariate general linear model (LRMGLM) for stimulus-evoked fMRI data. The new model not only is flexible to characterize variation in hemodynamic response functions (HRFs) across different regions and stimulus types, but also enables information "borrowing" across voxels and uses much fewer parameters than typical nonparametric models for HRFs. To estimate the proposed LRMGLM, we introduce a new penalized optimization function, which leads to temporally and spatially smooth HRF estimates. We develop an efficient optimization algorithm to minimize the optimization function and identify the voxels with different responses to stimuli. We show that the proposed method can outperform several existing voxel-wise methods by achieving both high sensitivity and specificity. We apply the proposed method to the fMRI data collected in an emotion study, and identify anterior dACC to have different responses to a designed threat and control stimuli.

Laboratory-induced learned helplessness attenuates approach motivation as indexed by posterior versus frontal theta activity.

Research suggests that midline posterior versus frontal electroencephalographic (EEG) theta activity (PFTA) may reflect a novel neurophysiological index of approach motivation. Elevated PFTA has been associated with approach-related tendencies both at rest and during laboratory tasks designed to enhance approach motivation. PFTA is sensitive to changes in dopamine signaling within the fronto-striatal neural circuit, which is centrally involved in approach motivation, reward processing, and goal-directed behavior. To date, however, no studies have examined PFTA during a laboratory task designed to reduce approach motivation or goal-directed behavior. Considerable animal and human research supports the hypothesis put forth by the learned helplessness theory that exposure to uncontrollable aversive stimuli decreases approach motivation by inducing a state of perceived uncontrollability. Accordingly, the present study examined the effect of perceived uncontrollability (i.e., learned helplessness) on PFTA. EEG data were collected from 74 participants (mean age = 19.21 years; 40 females) exposed to either Controllable (n = 26) or Uncontrollable (n = 25) aversive noise bursts, or a No-Noise Condition (n = 23). In line with prediction, individuals exposed to uncontrollable aversive noise bursts displayed a significant decrease in PFTA, reflecting reduced approach motivation, relative to both individuals exposed to controllable noise bursts or the No-Noise Condition. There was no relationship between perceived uncontrollability and frontal EEG alpha asymmetry, another commonly used neurophysiological index of approach motivation. Results have implications for understanding the neurophysiology of approach motivation and establishing PFTA as a neurophysiological index of approach-related tendencies.

Subjective General Health and the Social Regulation of Hypothalamic Activity.

OBJECTIVE: Social support is associated with better health. This association may be partly mediated through the social regulation of adrenomedullary activity related to poor cardiovascular health and glucocorticoid activity known to inhibit immune functioning. These physiological cascades originate in the hypothalamic areas that are involved in the neural response to threat. The aim of the study investigated whether the down regulation, by social support, of hypothalamic responses to threat is associated with better subjective health. METHODS: A diverse community sample of seventy-five individuals, aged 23 to 26 years, were recruited from an ongoing longitudinal study. Participants completed the Short Form Health Survey, a well-validated self-report measure used to assess subjective general health. They were scanned, using functional magnetic resonance imaging, during a threat of shock paradigm involving various levels of social support, which was manipulated using handholding from a close relational partner, a stranger, and an alone condition. We focused on a hypothalamic region of interest derived from an independent sample to examine the association between hypothalamic activity and subjective general health. RESULTS: Results revealed a significant interaction between handholding condition and self-reported general health (F(2,72) = 3.53, p = .032, partial η = 0.05). Down regulation of the hypothalamic region of interest during partner handholding corresponded with higher self-ratings of general health (ß = -0.31, p = .007). CONCLUSIONS: Higher self-ratings of general health correspond with decreased hypothalamic activity during a task that blends threat with supportive handholding. These results suggest that associations between social support and health are partly mediated through the social regulation of hypothalamic sensitivity to threat.

A semi-parametric nonlinear model for event-related fMRI.

Nonlinearity in evoked hemodynamic responses often presents in event-related fMRI studies. Volterra series, a higher-order extension of linear convolution, has been used in the literature to construct a nonlinear characterization of hemodynamic responses. Estimation of the Volterra kernel coefficients in these models is usually challenging due to the large number of parameters. We propose a new semi-parametric model based on Volterra series for the hemodynamic responses that greatly reduces the number of parameters and enables "information borrowing" among subjects. This model assumes that in the same brain region and under the same stimulus, the hemodynamic responses across subjects share a common but unknown functional shape that can differ in magnitude, latency and degree of interaction. We develop a computationally-efficient strategy based on splines to estimate the model parameters, and a hypothesis test on nonlinearity. The proposed method is compared with several existing methods via extensive simulations, and is applied to a real event-related fMRI study.

A semi-parametric model of the hemodynamic response for multi-subject fMRI data.

A semi-parametric model for estimating hemodynamic response function (HRF) from multi-subject fMRI data is introduced within the context of the General Linear Model. The new model assumes that the HRFs for a fixed brain voxel under a given stimulus share the same unknown functional form across subjects, but differ in height, time to peak, and width. A nonparametric spline-smoothing method is developed to evaluate this common functional form, based on which subject-specific characteristics of the HRFs can be estimated. This semi-parametric model explicitly characterizes the common properties shared across subjects and is flexible in describing various brain hemodynamic activities across different regions and stimuli. In addition, the temporal differentiability of the employed spline basis enables an easy-to-compute way of evaluating latency and width differences in hemodynamic activity. The proposed method is applied to data collected as part of an ongoing study of socially mediated emotion regulation. Comparison with several existing methods is conducted through simulations and real data analysis.

Mutuality and the social regulation of neural threat responding.

Recent studies have shown that the presence of a caring relational partner can attenuate neural responses to threat. Here we report reanalyzed data from Coan, Schaefer, and Davidson ( 2006 ), investigating the role of relational mutuality in the neural response to threat. Mutuality reflects the degree to which couple members show mutual interest in the sharing of internal feelings, thoughts, aspirations, and joys - a vital form of responsiveness in attachment relationships. We predicted that wives who were high (versus low) in perceived mutuality, and who attended the study session with their husbands, would show reduced neural threat reactivity in response to mild electric shocks. We also explored whether this effect would depend on physical contact (hand-holding). As predicted, we observed that higher mutuality scores corresponded with decreased neural threat responding in the right dorsolateral prefrontal cortex and supplementary motor cortex. These effects were independent of hand-holding condition. These findings suggest that higher perceived mutuality corresponds with decreased self-regulatory effort and attenuated preparatory motor activity in response to threat cues, even in the absence of direct physical contact with social resources.

Beyond Nature Versus Nurture: the Emergence of Emotion.

Affective science is stuck in a version of the nature-versus-nurture debate, with theorists arguing whether emotions are evolved adaptations or psychological constructions. We do not see these as mutually exclusive options. Many adaptive behaviors that humans have evolved to be good at, such as walking, emerge during development - not according to a genetically dictated program, but through interactions between the affordances of the body, brain, and environment. We suggest emotions are the same. As developing humans acquire increasingly complex goals and learn optimal strategies for pursuing those goals, they are inevitably pulled to particular brain-body-behavior states that maximize outcomes and self-reinforce via positive feedback loops. We call these recurring, self-organized states emotions. Emotions display many of the hallmark features of self-organized attractor states, such as hysteresis (prior events influence the current state), degeneracy (many configurations of the underlying variables can produce the same global state), and stability. Because most bodily, neural, and environmental affordances are shared by all humans - we all have cardiovascular systems, cerebral cortices, and caregivers who raised us - similar emotion states emerge in all of us. This perspective helps reconcile ideas that, at first glance, seem contradictory, such as emotion universality and neural degeneracy.

Nonparametric inference of the hemodynamic response using multi-subject fMRI data.

Estimation and inferences for the hemodynamic response functions (HRF) using multi-subject fMRI data are considered. Within the context of the General Linear Model, two new nonparametric estimators for the HRF are proposed. The first is a kernel-smoothed estimator, which is used to construct hypothesis tests on the entire HRF curve, in contrast to only summaries of the curve as in most existing tests. To cope with the inherent large data variance, we introduce a second approach which imposes Tikhonov regularization on the kernel-smoothed estimator. An additional bias-correction step, which uses multi-subject averaged information, is introduced to further improve efficiency and reduce the bias in estimation for individual HRFs. By utilizing the common properties of brain activity shared across subjects, this is the main improvement over the standard methods where each subject's data is usually analyzed independently. A fast algorithm is also developed to select the optimal regularization and smoothing parameters. The proposed methods are compared with several existing regularization methods through simulations. The methods are illustrated by an application to the fMRI data collected under a psychology design employing the Monetary Incentive Delay (MID) task.

Mechanisms supporting the social regulation of neural threat responding with marital partners: A test of the opioid hypothesis.

Positive social contact predicts better health, but the mechanisms for this association remain debated. One way to explore this link is through the social regulation of emotion, particularly anticipatory anxiety. Previous research finds less neural threat response during partner handholding than when people are alone or stranger handholding. Various mechanistic accounts have been forwarded, including the hypothesis that this effect is mediated by endogenous opioid activity. This experiment critically tested the opioid hypothesis in 60 married participants and their partners. The study used a naltrexone opioid blockade in a double-blind placebo control with functional magnetic resonance imaging to determine whether endogenous opioids were necessary for handholding effects. Regulatory effects of supportive handholding manifested in threat network regions during opioid blockade, but not with placebo. Despite a surprising lack of effect in the placebo group, the overall study findings provide initial evidence that endogenous opioids may not be necessary for the social regulation of neural threat responding.

Groups as organisms: Implications for therapy and training.

The intellectual tradition of individualism treats the individual person as the fundamental unit of analysis and reduces all things social to the motives and actions of individuals. Most methods in clinical psychology are influenced by individualism and therefore treat the individual as the primary object of therapy/training, even when recognizing the importance of nurturing social relationships for individual wellbeing. Multilevel selection theory offers an alternative to individualism in which individuals become part of something larger than themselves that qualifies as an organism in its own right. Seeing individuals as parts of social organisms provides a new perspective with numerous implications for improving wellbeing at all scales, from individuals to the planet.

The social regulation of emotion: Inconsistencies suggest no mediation through ventromedial prefrontal cortex.

Physical touch in the form of holding a loved one's hand attenuates the neural response to threat. Speculation regarding the neural mediation of this effect points to the ventromedial prefrontal cortex (vmPFC), which is known to have inhibitory connections with threat responsive brain regions such as the amygdala. Despite the attractiveness of this hypothesis, a link between the vmPFC and diminished threat during handholding has been difficult to demonstrate empirically. Here we report that in a sample of 110 participants no evidence for vmPFC mediation of the handholding effect was obtained. Indeed, results indicated that connectivity patterns between threat responsive salience network structures and the vmPFC were in the opposite direction one would predict if the vmPFC mediated reductions in neural threat-responding caused by partner handholding. Our findings suggest that the vmPFC does not mediate the regulating effect of physical contact on neural threat responses.

Yielding to social presence as a bioenergetic strategy.

All life must strategically conserve and allocate resources in order to meet the challenges of living. Social Baseline Theory suggests that, for humans, social context and the social resources therein are a central ecology in human phylogeny. In ontogeny, this manifests in flexible bioenergetic strategies that vary in the population based on social history. We introduce yielding, a conservation process wherein we relax physiological investment in response to a challenge when in the presence of a relational partner. The availability of these conserved resources then impact response to subsequent challenges while alone and if this pattern is habitual, it can reciprocally influence strategies used to solve or cope with typical stress. We discuss neural targets of this resource conservation and reframe our lab's previous studies on the social regulation of neural threat responding within this framework. We then show functional magnetic resonance imaging (fMRI) data indicating the presence of relational partners decreases blood-oxygen-level-dependent (BOLD) response to threat in key targets of resource conservation (e.g, dlPFC, dACC, and insula) and that stronger signal reduction in these areas coincide with less BOLD in pre-frontal (vmPFC, dlPFC) and visuo-sensory integration (occipital cortex, precuneus, superior parietal lobule) regions during ostracism. Finally, we show that these neural relationships are associated with less use of self-regulation-based coping strategies two years post scanning. Taken together, we show the utility of yielding both as a concept and as a bioenergetic process which helps to conserve energy in this social primate.

Social Allostasis and Social Allostatic Load: A New Model for Research in Social Dynamics, Stress, and Health.

Theories such as social baseline theory have argued that social groups serve a regulatory function but have not explored whether this regulatory process carries costs for the group. Allostatic load, the wear and tear on regulatory systems caused by chronic or frequent stress, is marked by diminished stress system flexibility and compromised recovery. We argue that allostatic load may develop within social groups as well and provide a model for how relationship dysfunction operates. Social allostatic load may be characterized by processes such as groups becoming locked into static patterns of interaction and may ultimately lead to up-regulation or down-regulation of a group's set point, or the optimal range of arousal or affect around which the group tends to converge. Many studies of emotional and physiological linkage within groups have reported that highly correlated states of arousal, which may reflect failure to maintain a group-level regulatory baseline, occur in the context of stress, conflict, and relationship distress. Relationship strain may also place greater demands on neurocognitive regulatory processes. Just as allostatic load may be detrimental to individual health, social allostatic load may corrode relationship quality.

Viewing cute images increases behavioral carefulness.

Infantile physical morphology-marked by its "cuteness"-is thought to be a potent elicitor of caregiving, yet little is known about how cuteness may shape immediate behavior. To examine the function of cuteness and its role in caregiving, the authors tested whether perceiving cuteness can enhance behavioral carefulness, which would facilitate caring for a small, delicate child. In 2 experiments, viewing very cute images (puppies and kittens)-as opposed to slightly cute images (dogs and cats)-led to superior performance on a subsequent fine-motor dexterity task (the children's game "Operation"). This suggests that the human sensitivity to those possessing cute features may be an adaptation that facilitates caring for delicate human young.

Empathy is associated with dynamic change in prefrontal brain electrical activity during positive emotion in children.

Empathy is the combined ability to interpret the emotional states of others and experience resultant, related emotions. The relation between prefrontal electroencephalographic asymmetry and emotion in children is well known. The association between positive emotion (assessed via parent report), empathy (measured via observation), and second-by-second brain electrical activity (recorded during a pleasurable task) was investigated using a sample of one hundred twenty-eight 6- to 10-year-old children. Contentment related to increasing left frontopolar activation (p < .05). Empathic concern and positive empathy related to increasing right frontopolar activation (ps < .05). A second form of positive empathy related to increasing left dorsolateral activation (p < .05). This suggests that positive affect and (negative and positive) empathy both relate to changes in prefrontal activity during a pleasurable task.

Dynamic variation in pleasure in children predicts nonlinear change in lateral frontal brain electrical activity.

Individual variation in the experience and expression of pleasure may relate to differential patterns of lateral frontal activity. Brain electrical measures have been used to study the asymmetric involvement of lateral frontal cortex in positive emotion, but the excellent time resolution of these measures has not been used to capture second-by-second changes in ongoing emotion until now. The relationship between pleasure and second-by-second lateral frontal activity was examined with the use of hierarchical linear modeling in a sample of 128 children ages 6-10 years. Electroencephalographic activity was recorded during "pop-out toy," a standardized task that elicits pleasure. The task consisted of 3 epochs: an anticipation period sandwiched between 2 play periods. The amount of pleasure expressed during the task predicted the pattern of nonlinear change in lateral frontal activity. Children who expressed increasing amounts of pleasure during the task exhibited increasing left lateral frontal activity during the task, whereas children who expressed contentment exhibited increasing right/decreasing left activity. These findings indicate that task-dependent changes in pleasure relate to dynamic, nonlinear changes in lateral frontal activity as the task unfolds.

Brain mechanisms of social touch-induced analgesia in females.

Supportive touch has remarkable benefits in childbirth and during painful medical procedures. But does social touch influence pain neurophysiology, ie, the brain processes linked to nociception and primary pain experience? What other brain processes beyond primary pain systems mediate their analgesic effects? In this study, women (N = 30) experienced thermal pain while holding their romantic partner's hand or an inert device. Social touch reduced pain and attenuated functional magnetic resonance imaging activity in the Neurologic Pain Signature (NPS)-a multivariate brain pattern sensitive and specific to somatic pain-and increased connectivity between the NPS and both somatosensory and "default mode" regions. Brain correlates of touch-induced analgesia included reduced pain-related activation in (1) regions targeted by primary nociceptive afferents (eg, posterior insula, and anterior cingulate cortex); and (b) regions associated with affective value (orbitofrontal cortex), meaning (ventromedial prefrontal cortex [PFC]), and attentional regulation (dorsolateral PFC). Activation reductions during handholding (vs holding a rubber device) significantly mediated reductions in pain intensity and unpleasantness; greater pain reductions during handholding correlated with greater increases in emotional comfort, which correlated with higher perceived relationship quality and (a trend toward) greater perceived closeness with the romantic partner. The strongest mediators of analgesia were activity reductions in a brain circuit traditionally associated with stress and defensive behavior in mammals, including ventromedial and dorsomedial PFC, rostral anterior cingulate cortex, amygdala/hippocampus, hypothalamus, and periaqueductal gray matter. Social touch affects core brain processes that contribute to pain and pain-related affective distress in females, and should be considered alongside other treatments in medical and caregiving contexts.