A mathematical model for the dynamics of happiness.

Positive psychology recognizes happiness as a construct comprising hedonic and eudaimonic well-being dimensions. Integrating these components and a set of theory-led assumptions, we propose a mathematical model, given by a system of nonlinear ordinary differential equations, to describe the dynamics of a person's happiness over time. The mathematical model offers insights into the role of emotions for happiness and why we struggle to attain sustainable happiness and tread the hedonic treadmill oscillating around a relative stable level of well-being. The model also indicates that lasting happiness may be achievable by developing constant eudaimonic emotions or human altruistic qualities that overcome the limits of the homeostatic hedonic system; in mathematical terms, this process is expressed as distinct dynamical bifurcations. This mathematical description is consistent with the idea that eudaimonic well-being is beyond the boundaries of hedonic homeostasis.

Attentional and cognitive monitoring brain networks in long-term meditators depend on meditation states and expertise.

Meditation practice is suggested to engage training of cognitive control systems in the brain. To evaluate the functional involvement of attentional and cognitive monitoring processes during meditation, the present study analysed the electroencephalographic synchronization of fronto-parietal (FP) and medial-frontal (MF) brain networks in highly experienced meditators during different meditation states (focused attention, open monitoring and loving kindness meditation). The aim was to assess whether and how the connectivity patterns of FP and MF networks are modulated by meditation style and expertise. Compared to novice meditators, (1) highly experienced meditators exhibited a strong theta synchronization of both FP and MF networks in left parietal regions in all mediation styles, and (2) only the connectivity of lateralized beta MF networks differentiated meditation styles. The connectivity of intra-hemispheric theta FP networks depended non-linearly on meditation expertise, with opposite expertise-dependent patterns found in the left and the right hemisphere. In contrast, inter-hemispheric FP connectivity in faster frequency bands (fast alpha and beta) increased linearly as a function of expertise. The results confirm that executive control systems play a major role in maintaining states of meditation. The distinctive lateralized involvement of FP and MF networks appears to represent a major functional mechanism that supports both generic and style-specific meditation states. The observed expertise-dependent effects suggest that functional plasticity within executive control networks may underpin the emergence of unique meditation states in expert meditators.

Common and distinct lateralised patterns of neural coupling during focused attention, open monitoring and loving kindness meditation.

Meditation has been integrated into different therapeutic interventions. To inform the evidence-based selection of specific meditation types it is crucial to understand the neural processes associated with different meditation practices. Here we explore commonalities and differences in electroencephalographic oscillatory spatial synchronisation patterns across three important meditation types. Highly experienced meditators engaged in focused attention, open monitoring, and loving kindness meditation. Improving on previous research, our approach avoids comparisons between groups that limited previous findings, while ensuring that the meditation states are reliably established. Employing a novel measure of neural coupling - the imaginary part of EEG coherence - the study revealed that all meditation conditions displayed a common connectivity pattern that is characterised by increased connectivity of (a) broadly distributed delta networks, (b) left-hemispheric theta networks with a local integrating posterior focus, and (c) right-hemispheric alpha networks, with a local integrating parieto-occipital focus. Furthermore, each meditation state also expressed specific synchronisation patterns differentially recruiting left- or right-lateralised beta networks. These observations provide evidence that in addition to global patterns, frequency-specific inter-hemispheric asymmetry is one major feature of meditation, and that mental processes specific to each meditation type are also supported by lateralised networks from fast-frequency bands.

Autistic traits modulate cortical responses to affective but not discriminative touch.

The sense of touch is primarily considered a discriminative and exteroceptive sense, facilitating the detection, manipulation and exploration of objects, via an array of low-threshold mechanoreceptors and fast conducting A-beta (Aß) afferents. However, a class of unmyelinated, low-threshold mechanoreceptors identified in the hairy skin of mammals have been proposed to constitute a second, anatomically distinct system coding the affective qualities of touch. Unlike Aßs, which increase their firing rate linearly with the velocity of a stimulus moving across their receptive field, the response of these C-tactile afferents (CTs) is described by an inverted 'U' curve fit, responding optimally to a skin temperature stimulus moving at between 1 and 10 cm/s. Given the distinct velocity tuning of these fast and slow touch fibres, here we used event-related potentials to compare the time course of neural responses to 1st (fast) and 2nd (slow) touch systems. We identified a higher amplitude P300 in response to fast, Aß-targeted, versus slow CT-targeted, stroking touch. In contrast, we identified a previously described, C-fibre specific, ultra-late potential (ULP) associated with CT-targeted input. Of special note as regards the function of CTs is that the amplitude of the ULP was negatively correlated with self-reported levels of autistic traits, which is consistent with the hypothesized affective and social significance of this response. Taken together, these findings provide further support for distinct discriminative and affective touch systems and suggests the temporal resolution of EEG provides an as yet underutilized tool for exploring individual differences in response sensitivity to CT-targeted touch.

Short-term mindful breath awareness training improves inhibitory control and response monitoring.

Mindfulness meditation is thought to lead to positive changes in cognitive and affective functioning. However, the mechanisms underlying these changes are not well understood. One reason for this is that so far only very few studies considered the effects of specific meditation practices. We thus investigated the effects of engaging in one specific form of mindfulness meditation for a brief time period on behavioral and neural indicators of inhibitory control and metacognition. Performance on the Go/No-Go task and concurrent neural activity (EEG) was assessed before and after participants engaged in 3 weeks of mindful breath awareness meditation. Compared to a waitlist control group, meditation training enhanced the N2 event-related potential in No-Go trials and the error-related negativity (ERN) after error responses. As these two components reflect conflict and response monitoring, respectively, our results support the notion that mindfulness meditation improves metacognitive processes. The changes in the ERN were correlated with the accumulated amount of meditation time, highlighting the importance of meditation practice. Furthermore, meditation improved a behavioral marker of impulsive responding, indicating the relevance of mindfulness-based approaches for supporting health-related behaviors that are associated with deficits in impulsive control, such as substance abuse or over-eating. This study demonstrated that investigating one particular meditation practice rather than complex mindfulness-based interventions can contribute to a deeper understanding of mindfulness meditation mechanisms.

Mindful breath awareness meditation facilitates efficiency gains in brain networks: A steady-state visually evoked potentials study.

The beneficial effects of mindfulness-based therapeutic interventions have stimulated a rapidly growing body of scientific research into underlying psychological processes. Resulting evidence indicates that engaging with mindfulness meditation is associated with increased performance on a range of cognitive tasks. However, the mechanisms promoting these improvements require further investigation. We studied changes in behavioural performance of 34 participants during a multiple object tracking (MOT) task that taps core cognitive processes, namely sustained selective visual attention and spatial working memory. Concurrently, we recorded the steady-state visually evoked potential (SSVEP), an EEG signal elicited by the continuously flickering moving objects, and indicator of attentional engagement. Participants were tested before and after practicing eight weeks of mindful breath awareness meditation or progressive muscle relaxation as active control condition. The meditation group improved their MOT-performance and exhibited a reduction of SSVEP amplitudes, whereas no such changes were observed in the relaxation group. Neither group changed in self-reported positive affect and mindfulness, while a marginal increase in negative affect was observed in the mindfulness group. This novel way of combining MOT and SSVEP provides the important insight that mindful breath awareness meditation may lead to refinements of attention networks, enabling more efficient use of attentional resources.

Dispositional mindfulness and reward motivated eating: The role of emotion regulation and mental habit.

Evidence regarding the effectiveness of mindfulness based interventions (MBIs) for eating disorders, weight management and food craving is emerging and further studies are required to understand the underlying mechanisms of MBIs in these domains. The current study was designed to establish the role of specific mechanisms underlying the putative relationship between mindfulness and reward motivated eating. We predicted that mindfulness would be negatively related to features of reward motivated eating and that this association would be mediated by emotion regulation and habitual negative self-thinking. A cross-sectional survey measuring uncontrolled and emotional eating, mindfulness, emotion regulation and habitual negative self-thinking was completed by female and male meditators and non-meditators (N = 632). Lower levels of dispositional mindfulness were associated with difficulties in emotion regulation, habitual negative self-thinking and both emotional and uncontrolled eating. Difficulties in emotion regulation significantly mediated the mindfulness-uncontrolled eating relationship. Habitual negative self-thinking significantly mediated the mindfulness-emotional eating relationship. Participants with meditation experience reported greater levels of dispositional mindfulness, fewer difficulties with emotion regulation and habitual negative self-thinking and reduced uncontrolled eating tendencies, compared to non-meditators. The findings suggest that MBIs designed to change reward motivated eating and weight control should focus on emotion regulation and mental habits as underlying mechanisms.

Frontal Theta Dynamics during Response Conflict in Long-Term Mindfulness Meditators.

Mindfulness meditators often show greater efficiency in resolving response conflicts than non-meditators. However, the neural mechanisms underlying the improved behavioral efficiency are unclear. Here, we investigated frontal theta dynamics-a neural mechanism involved in cognitive control processes-in long-term mindfulness meditators. The dynamics of EEG theta oscillations (4-8 Hz) recorded over the medial frontal cortex (MFC) were examined in terms of their power (MFC theta power) and their functional connectivity with other brain areas (the MFC-centered theta network). Using a flanker-type paradigm, EEG data were obtained from 22 long-term mindfulness meditators and compared to those from 23 matched controls without meditation experience. Meditators showed more efficient cognitive control after conflicts, evidenced by fewer error responses irrespective of response timing. Furthermore, meditators exhibited enhanced conflict modulations of the MFC-centered theta network shortly before the response, in particular for the functional connection between the MFC and the motor cortex. In contrast, MFC theta power was comparable between groups. These results suggest that the higher behavioral efficiency after conflicts in mindfulness meditators could be a function of increased engagement to control the motor system in association with the MFC-centered theta network.

Mindful Aging: The Effects of Regular Brief Mindfulness Practice on Electrophysiological Markers of Cognitive and Affective Processing in Older Adults.

There is growing interest in the potential benefits of mindfulness meditation practices in terms of counteracting some of the cognitive effects associated with aging. Pursuing this question, the aim of the present study was to investigate the influence of mindfulness training on executive control and emotion regulation in older adults, by means of studying behavioral and electrophysiological changes. Participants, 55 to 75 years of age, were randomly allocated to an 8-week mindful breath awareness training group or an active control group engaging in brain training exercises. Before and after the training period, participants completed an emotional-counting Stroop task, designed to measure attentional control and emotion regulation processes. Concurrently, their brain activity was measured by means of 64-channel electroencephalography. The results show that engaging in just over 10 min of mindfulness practice five times per week resulted in significant improvements in behavioral (response latency) and electrophysiological (N2 event-related potential) measures related to general task performance. Analyses of the underlying cortical sources (Variable Resolution Electromagnetic Tomography, VARETA) indicate that this N2-related effect is primarily associated with changes in the right angular gyrus and other areas of the dorsal attention network. However, the study did not find the expected specific improvements in executive control and emotion regulation, which may be due to the training instructions or the relative brevity of the intervention. Overall, the results indicate that engaging in mindfulness meditation training improves the maintenance of goal-directed visuospatial attention and may be a useful strategy for counteracting cognitive decline associated with aging.

'I can't accept that feeling': Relationships between interoceptive awareness, mindfulness and eating disorder symptoms in females with, and at-risk of an eating disorder.

Mindfulness based therapies (MBTs) for eating disorders show potential benefit for outcomes yet evidence is scarce regarding the mechanisms by which they influence remission from symptoms. One way that mindfulness approaches create positive outcomes is through enhancement of emotion regulation skills. Maladaptive emotion regulation is a key psychological feature of all eating disorders. The aim of the current study was to identify facets of emotion regulation involved in the relationship between mindfulness and maladaptive eating behaviours. In three cross-sectional studies, clinical (n=39) and non-clinical (n=137 and 119) female participants completed: 1) the Eating Disorder Inventory (EDI) eating specific scales (drive-for-thinness and bulimia) and the EDI psychological symptom scales (emotion dysregulation and interoceptive deficits); and 2) mindfulness, impulsivity, and emotion regulation questionnaires. In all samples mindfulness was significantly and inversely associated with EDI eating and psychological symptom scales, and impulsivity. In non-clinical samples interoceptive deficits mediated the relationship between mindfulness and EDI eating specific scales. Non-acceptance of emotional experience, a facet of interoceptive awareness, mediated the relationship between mindfulness and eating specific EDI scores. Further investigations could verify relationships identified so that mindfulness based approaches can be optimised to enhance emotion regulation skills in sufferers, and those at-risk, of eating disorders.

Attention with a mindful attitude attenuates subjective appetitive reactions and food intake following food-cue exposure.

BACKGROUND: Excessive energy intake that contributes to overweight and obesity is arguably driven by pleasure associated with the rewarding properties of energy-dense palatable foods. It is important to address influences of external food cues in food-abundant societies where people make over 200 food related decisions each day. This study experimentally examines protective effects of a mindful attention induction on appetitive measures, state craving and food intake following exposure to energy-dense foods. METHOD: Forty females were randomly allocated to a standard food-cue exposure condition in which attention is brought to the hedonic properties of food or food-cue exposure following a mindful attention induction. Appetitive reactions were measured pre, post and 10 min after post-cue exposure, after which a plate of cookies was used as a surreptitious means of measuring food intake. RESULTS: Self-reported hunger remained unchanged and fullness significantly increased for the mindful attention group post-cue exposure whereas hunger significantly increased for the standard attention group and fullness remained unchanged. There was no significant between-group difference in state craving post-cue exposure and 10 min later. Significantly more cookies were eaten by the standard attention group 10 min post-cue exposure although no significant between-group differences in appetitive and craving measures were reported at that time. CONCLUSION: Our results point to a promising brief intervention strategy and highlights the importance of distinguishing mindful attention from attention. Results also demonstrate that mindful attention can influence food intake even when craving and hunger are experienced.

Neural mechanisms of attentional control in mindfulness meditation.

The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

Regular, brief mindfulness meditation practice improves electrophysiological markers of attentional control.

Mindfulness-based meditation practices involve various attentional skills, including the ability to sustain and focus ones attention. During a simple mindful breathing practice, sustained attention is required to maintain focus on the breath while cognitive control is required to detect mind wandering. We thus hypothesized that regular, brief mindfulness training would result in improvements in the self-regulation of attention and foster changes in neuronal activity related to attentional control. A longitudinal randomized control group EEG study was conducted. At baseline (T1), 40 meditation naïve participants were randomized into a wait list group and a meditation group, who received three hours mindfulness meditation training. Twenty-eight participants remained in the final analysis. At T1, after eight weeks (T2) and after 16 weeks (T3), all participants performed a computerized Stroop task (a measure of attentional control) while the 64-channel EEG was recorded. Between T1 and T3 the meditators were requested to meditate daily for 10 min. Event-related potential (ERP) analysis highlighted two between group effects that developed over the course of the 16-week mindfulness training. An early effect at left and right posterior sites 160-240 ms post-stimulus indicated that meditation practice improved the focusing of attentional resources. A second effect at central posterior sites 310-380 ms post-stimulus reflects that meditation practice reduced the recruitment of resources during object recognition processes, especially for incongruent stimuli. Scalp topographies and source analyses (Variable Resolution Electromagnetic Tomography, VARETA) indicate relevant changes in neural sources, pertaining to left medial and lateral occipitotemporal areas for the early effect and right lateral occipitotemporal and inferior temporal areas for the later effect. The results suggest that mindfulness meditation may alter the efficiency of allocating cognitive resources, leading to improved self-regulation of attention.

Mindfulness-based approaches: are they all the same?

Mindfulness-based approaches are increasingly employed as interventions for treating a variety of psychological, psychiatric and physical problems. Such approaches include ancient Buddhist mindfulness meditations such as Vipassana and Zen meditations, modern group-based standardized meditations, such as mindfulness-based stress reduction and mindfulness-based cognitive therapy, and further psychological interventions, such as dialectical behavioral therapy and acceptance and commitment therapy. We review commonalities and differences of these interventions regarding philosophical background, main techniques, aims, outcomes, neurobiology and psychological mechanisms. In sum, the currently applied mindfulness-based interventions show large differences in the way mindfulness is conceptualized and practiced. The decision to consider such practices as unitary or as distinct phenomena will probably influence the direction of future research.

A cross-sectional investigation of trait disinhibition and its association with mindfulness and impulsivity.

Two online surveys were conducted to assess the relationship between trait disinhibition, impulsivity, mindfulness and adverse psychological symptoms. In study 1 adult females (n=196; mean age=21 yrs) completed the Three-Factor Eating Questionnaire (TEFQ-R21), the Hospital Anxiety and Depression Scale and a measure of dispositional mindfulness. In study 2 adult females (n=190; mean age=26 yrs) completed the same measures as in study 1 with the addition of the Barratt Impulsivity Scale. In both studies it was predicted that mindfulness would be negatively related to trait disinhibition controlling for adverse psychological symptoms. The second study addressed the additional hypothesis that the relationship between mindfulness and trait disinhibition would be mediated by impulsivity. Regression analyses indicated that mindfulness was negatively related to and explained 11% of variation in trait disinhibition (study 1). This relationship was replicated and extended in study 2 whereby impulsivity mediated the relationship between mindfulness and trait disinhibition. The findings warrant experimental and in vivo investigations of the potential causal relationships between mindfulness, impulsivity and eating behaviours.

Meditation, mindfulness and cognitive flexibility.

This study investigated the link between meditation, self-reported mindfulness and cognitive flexibility as well as other attentional functions. It compared a group of meditators experienced in mindfulness meditation with a meditation-naïve control group on measures of Stroop interference and the "d2-concentration and endurance test". Overall the results suggest that attentional performance and cognitive flexibility are positively related to meditation practice and levels of mindfulness. Meditators performed significantly better than non-meditators on all measures of attention. Furthermore, self-reported mindfulness was higher in meditators than non-meditators and correlations with all attention measures were of moderate to high strength. This pattern of results suggests that mindfulness is intimately linked to improvements of attentional functions and cognitive flexibility. The relevance of these findings for mental balance and well-being are discussed.

Sustained division of spatial attention to multiple locations within one hemifield.

Attending to a location in space significantly improves stimulus perception at that location. Everyday experience requires the deployment of attention to multiple objects at different locations. Recent empirical evidence suggests that the "beam" of attention can be divided between non-contiguous areas of the visual field. Whether this is only possible when stimuli are presented in different hemifields and harder, if not impossible, when stimuli are in the same hemifield is an ongoing debate. Here we use an electrophysiological measure of sustained attentional resource allocation (the steady-state visual evoked potential, SSVEP) to address this question. In combination with behavioural data we demonstrate that splitting the attentional "beam" is in principle possible within one hemifield. However, results showed that task performance was in general lower for same-hemifield presentation as opposed to our previous study with different-hemifield presentation [M.M. Müller, P. Malinowski, T. Gruber, S.A. Hillyard, Sustained division of the attentional spotlight, Nature 424 (2003) 309-312]. SSVEP amplitude showed a mixed pattern of results for stimuli presented in the upper versus lower quadrant of the left visual hemifield under conditions of attending to two separated locations. Results are discussed in the light of the bilateral distribution advantage hypothesis and differences in stimulus salience between the upper and lower visual field.

Modulation of oscillatory brain activity and evoked potentials in a repetition priming task in the human EEG.

Cortical object representations seem to require the formation of neural cell assemblies. The physiological correlate of cell assembly activity may be seen in synchronized neural activity in the gamma band range. The improvement in perceiving and identifying an object by experience is commonly referred to as repetition priming. One possible neural mechanism for repetition priming is 'repetition suppression' within a cell assembly coding the stimulus. The present electroencephalogram study was designed to investigate oscillatory brain activity when line drawings of concrete objects were repeated either immediately after a first presentation or after intervening a number of different stimuli. Results showed a broad posterior distribution of induced gamma band responses (GBRs) after the initial picture presentation. Repeated presentations of the same picture led to a significant decrease of induced gamma power. Furthermore, repeated presentations of the same object resulted in a decrease in phase synchrony between distant electrode sites. No significant repetition effects were found in the alpha or beta frequency range. The event-related potential (ERP), which was also modulated by priming, showed a different scalp distribution compared with induced GBRs. In addition, ERP repetition effects decayed at larger intervals between initial and repeated presentations, whereas induced GBRs were not modulated as a function of stimulus lag. We concluded that the decrease in amplitude of induced GBRs and the reduction of gamma phase synchrony between pairs of electrodes after repeated picture presentations might be linked to a 'sharpening' mechanism within a cell assembly representing an object.

The influence of response competition on cerebral asymmetries for processing hierarchical stimuli revealed by ERP recordings.

It is widely accepted that the left and right hemispheres differ with respect to the processing of global and local aspects of visual stimuli. Recently, behavioural experiments have shown that this processing asymmetry strongly depends on the response competition between the global and local levels of a stimulus. Here we report electrophysiological data that underline this observation. Hemispheric differences for global/local processing were mainly observed for response-incompatible stimuli and were most prominent between 320 and 400 ms after stimulus onset. These results underpin the idea that hemispheric differences are more likely to show up when a more elaborated stimulus representation is needed for triggering the response, that is, when a response conflict has to be resolved.

The effect of response competition on functional hemispheric asymmetries for global/local processing.

It is widely assumed that the cerebral hemispheres differ in their capacity for processing the global and local levels of hierarchical stimuli. However, corresponding visual-field (VF) effects in response time studies did not show up under all circumstances. In the present article the role of response conflict between the levels for the occurrence of these effects is investigated. Three experiments with hierarchical letters are reported, in which the absolute and/or the relative interference between the stimulus levels was varied. It turned out that VF effects occurred only for conflicting stimuli and only when there was at least a certain amount of absolute interference, whereas variations of the relative interference had no effect in this respect. These results suggest that there is a qualitative relationship between interference and VF effects. A possible explanation is provided by the assumption that the hemispheres are functionally equivalent with respect to early stimulus representations, whereas they differ in their efficiency for integrating letter identity and stimulus level.