Event-related theta and alpha oscillations mediate empathy for pain

The mutual influences between working memory and empathy for pain: the role of social distance

Understanding the mechanisms behind the interaction of empathy for pain (EfP) and working memory (WM), particularly how they are influenced by social factors like perceived social distance (SD), is vital for comprehending how humans dynamically adapt to the complexities of social life. However, there is very little known about these mechanisms. Accordingly, we recruited 116 healthy participants to investigate the bidirectional influence and electrophysiological responses between WM and EfP, including the role of SD. Our research results revealed that the interaction between WM load and SD significantly influenced the processing of EfP. Specifically, high WM load and distant SD facilitated early processing of EfP. Conversely, low WM load and close SD promoted late processing of EfP. Furthermore, the interaction between EfP and SD significantly influenced the performance of ongoing WM tasks. Specifically, the kin's pain, compared to kin's nonpain, improved the participant's performance on low-load WM tasks; however, it diminished the participant's performance on tasks with high WM load. Overall, these results provide evidence at both behavioral and neural levels for the mutual influence of WM and EfP during the same temporal process, and SD emerged as a crucial moderating factor during these mutual influences.

Unraveling the physiological and psychosocial signatures of pain by machine learning

BACKGROUND

Pain is a complex subjective experience, strongly impacting health and quality of life. Despite many attempts to find effective solutions, present treatments are generic, often unsuccessful, and present significant side effects. Designing individualized therapies requires understanding of multidimensional pain experience, considering physical and emotional aspects. Current clinical pain assessments, relying on subjective one-dimensional numeric self-reports, fail to capture this complexity.

METHODS

To this aim, we exploited machine learning to disentangle physiological and psychosocial components shaping the pain experience. Clinical, psychosocial, and physiological data were collected from 118 chronic pain and healthy participants undergoing 40 pain trials (4,697 trials).

FINDINGS

To understand the objective response to nociception, we classified pain from the physiological signals (accuracy >0.87), extracting the most important biomarkers. Then, using multilevel mixed-effects models, we predicted the reported pain, quantifying the mismatch between subjective level and measured physiological response. From these models, we introduced two metrics: TIP (subjective index of pain) and Φ (physiological index). These represent possible added value in the clinical process, capturing psychosocial and physiological pain dimensions, respectively. Patients with high TIP are characterized by frequent sick leave from work and increased clinical depression and anxiety, factors associated with long-term disability and poor recovery, and are indicated for alternative treatments, such as psychological ones. By contrast, patients with high Φ show strong nociceptive pain components and could benefit more from pharmacotherapy.

CONCLUSIONS

TIP and Φ, explaining the multidimensionality of pain, might provide a new tool potentially leading to targeted treatments, thereby reducing the costs of inefficient generic therapies.

FUNDING

RESC-PainSense, SNSF-MOVE-IT197271.

Inter-brain entrainment (IBE) during interoception. A multimodal EEG-fNIRS coherence-based hyperscanning approach

This work examined the impact of interoceptive manipulation and the presence of a shared goal on inter-brain entrainment (IBE) during a motor synchronization task. A multimodal functional Near Infrared Spectroscopy - Electroencephalogram (fNIRS-EEG) system-based hyperscanning approach was applied to 13 dyads performing the motor synchrony task during an interoceptive (focus on the breath) and control condition. Additionally, two version of the motor task-one with and one without a clearly defined common goal-were presented to participants to emphasize the task's collaborative purpose. The multimodal approach was exploited to record the electrophysiological (EEG) cortical oscillation and hemodynamic (oxy-Hb and deoxy-Hb) levels. Results revealed significant correlations between EEG delta, theta, and alpha band and hemodynamic oxy-Hb in the left compared to right hemisphere for the interoceptive confronted with the control condition. This significant EEG/fNIRS IBE correlation was also found for delta and theta band whereas the task was presented with an explicit shared goal confronted with the no-social version. In addition to separate functional connectivity EEG and fNIRS analysis, this study proposed a novel analysis pipeline including statistical tests for examining the coherence between functional connectivity EEG-fNIRS signals within couples. Besides proposing methodological advancements on EEG-fNIRS signals hyperscanning analysis, this research demonstrated that, in dyads undertaking a motor synchronization task, both the interoceptive attention to respiration and an explicit joint intention activate left anterior regions.

EEG evidence for racial ingroup bias in collective empathy for pain

Previous research on racial ingroup bias in empathy for pain focused on neural responses to a single person's suffering. It is unclear whether empathy for simultaneously perceived multiple individuals' pain (denoted as collective empathy in this study) is also sensitive to perceived racial identities of empathy targets. We addressed this issue by recording electroencephalography from Chinese adults who responded to racial identities of 2 × 2 arrays of Asian or White faces in which 4 faces, 1 face, or no face showed painful expressions. Participants reported greater feelings of others' pain and their own unpleasantness when viewing 4 compared to 1 (or no) painful faces. Behavioral responses to racial identities of faces revealed decreased speeds of information acquisition when responding to the face arrays with 4 (vs. 1 or no) painful expressions of Asian (but not White) faces. Moreover, Asian compared to White face arrays with 4 (vs. 1 or no) painful expressions elicited a larger positive neural response at 160-190 ms (P2) at the frontal/central electrodes and enhanced alpha synchronizations at 288-1,000 ms at the central electrodes. Our findings provide evidence for racial ingroup biases in collective empathy for pain and unravel its relevant neural underpinnings.

Altered neurophysiological responses during empathy for pain in insomnia: evidence from an EEG study in non-clinical samples

BACKGROUND

This study aims to investigate the behavioral and neurophysiological changes accompanying the empathy for pain among individuals with insomnia in nonclinical samples, which has been scarcely explored in the existing literature despite the deleterious effects of sleep disturbance on social behavior, and interactions had been well-documented.

METHODS

Twenty-one individuals with insomnia in nonclinical samples and 20 healthy individuals as normal controls participated in the study. Electroencephalograph (EEG) was continuously recorded, while the participants underwent an empathy for pain task.

RESULTS

Subjective ratings of pain for painful and non-painful images revealed no statistically significant differences between the insomnia and control groups. The painful images induced a smaller P2 compared to non-painful images in the insomnia group, whereas no such difference was revealed for the controls. Moreover, a higher power density of the alpha and theta2 bands in the posterior brain regions was found in the insomnia group compared to the control group.

CONCLUSION

These findings suggest that individuals with insomnia exhibit altered neurophysiological responses to pain stimuli and a lower capacity to share empathy for pain. These alterations may be associated with changes in attentional mechanisms.

Relationship between individual differences in pain empathy and task- and resting-state EEG

Pain empathy is a complex form of psychological inference that enables us to understand how others feel in the context of pain. Since pain empathy may be grounded in our own pain experiences, it exhibits huge inter-individual variability. However, the neural mechanisms behind the individual differences in pain empathy and its association with pain perception are still poorly understood. In this study, we aimed to characterize brain mechanisms associated with individual differences in pain empathy in adult participants (n = 24). The 32-channel electroencephalography (EEG) was recorded at rest and during a pain empathy task, and participants viewed static visual stimuli of the limbs submitted to painful and nonpainful stimulation to solicit empathy. The pain sensitivity of each participant was measured using a series of direct current stimulations. In our results, the N2 of Fz and the LPP of P3 and P4 were affected by painful pictures. We found that both delta and alpha bands in the frontal and parietal cortex were involved in the regulation of pain empathy. For the delta band, a close relationship was found between average power, either in the resting or task state, and individual differences in pain empathy. It suggested that the spectral power in Fz's delta band may reflect subjective pain empathy across individuals. For the alpha band, the functional connectivity between Fz and P3 under painful picture stimulation was correlated to individuals' pain sensitivity. It indicated that the alpha band may reflect individual differences in pain sensitivity and be involved in pain empathy processing. Our results suggested the distinct role of the delta and alpha bands of EEG signals in pain empathy processing and may deepen our understanding of the neural mechanisms underpinning pain empathy.

Neural dynamics of vicarious physical pain processing reflect impaired empathy toward sexually objectified versus non-sexually objectified women

Sexually objectified women are perceived as dehumanized. This may affect the behavioral and neural responses underlying the observer's empathic reactions for their physical pain, although this hypothesis still lacks empirical support. In the present study, we measured the electrophysiological activity of 30 participants (14 females and 16 males), in an empathy for physical pain paradigm in which pictures of sexualized and non-sexualized women were presented in painful and non-painful situations. The behavioral results revealed that sexualized women were evaluated as experiencing less pain than non-sexualized women. Neural evidence corroborated this finding showing that the perception of vicarious physical pain is lacking for sexualized women in both event-related potentials (ERPs) and brain oscillation domains. Specifically, the P2 component and the event-related synchronization/desynchronization (ERS/ERD) on the mu frequency band differed between painful and non-painful stimulation exclusively when women were not sexualized. Our results provide the first evidence that the neurophysiological responses to the vicarious experience of physical pain are dampened or even absent for sexualized women. These findings expand our understanding of the neurophysiological signatures of empathic processes and highlight the detrimental effect of a sexual-objectification bias in everyday contexts.

Neural mechanisms of priming effects of spicy food pictures induced analgesia

In this study, the effects of the priming of spicy food pictures on pain perception were evaluated in female participants using standardized methods of pain. Results from behavior tests revealed that the priming of spicy food pictures significantly reduced pain perception, particularly at high-pain intensities. Electrophysiological analysis showed that the analgesic effects of spicy food pictures were linked to decreased pain-related event-related potentials, such as N2 and P2 amplitudes, and suppressed θ-oscillations in the sensorimotor cortex. Both N2 amplitudes and θ-oscillations activities were found to be correlated with participants' pain perception. These results suggest that spicy-arousal stimuli may act as an "antagonist" to the increase in N2 amplitudes and θ-oscillations power induced by pain and influence the neuronal networks involved in integrating spontaneous nociceptive resources, which supports the dissociation theory of pain sensation and affection. These findings highlight the potential use of spicy-arousal stimuli as an analgesic and emphasize the importance of considering both the intensity of the stimuli and the individual's emotional state in the assessment and treatment of pain.

Effects of social presence on behavioral, neural, and physiological aspects of empathy for pain

In mediated interactions (e.g. video calls), less information is available about the other. To investigate how this affects our empathy for one another, we conducted an electroencephalogram study, in which 30 human participants observed 1 of 5 targets undergoing painful electric stimulation, once in a direct interaction and once in a live, video-mediated interaction. We found that observers were as accurate in judging others' pain and showed as much affective empathy via video as in a direct encounter. While mu suppression, a common neural marker of empathy, was not sensitive to others' pain, theta responses to others' pain as well as skin conductance coupling between participants were reduced in the video-mediated condition. We conclude that physical proximity with its rich social cues is important for nuanced physiological resonance with the other's experience. More studies are warranted to confirm these results and to understand their behavioral significance for remote social interactions.

Neural shifts in alpha rhythm's dual functioning during empathy maturation

INTRODUCTION

Empathy is a social-cognitive process that operates by relying mainly on the suppression of the cortical alpha rhythm. This phenomenon has been evidenced in dozens of electrophysiological studies targeting adult human subjects. Yet, recent neurodevelopmental studies indicated that at a younger age, empathy involves reversed brain responses (e.g., alpha enhancement patterns). In this multimodal study, we capture neural activity at the alpha range, and hemodynamic response and target subjects at approximately 20 years old as a unique time window in development that allows investigating both low-alpha suppression and high-alpha enhancement. We aim to further investigate the functional role of low-alpha power suppression and high-alpha power enhancement during empathy development.

METHODS

Brain data from 40 healthy individuals were recorded in two consecutive sessions of magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) while subjects perceived vicarious physical pain or no pain.

RESULTS

MEG revealed that the alpha pattern shift during empathy happens in an all-or-none pattern: power enhancement before 18 and suppression after 18 years of age. Additionally, MEG and fMRI highlight a correspondence between high-alpha power increase and blood-oxygen-level-dependent (BOLD) decrease before 18, but low-alpha power decrease and BOLD increase after 18. Importantly, this neurodevelopmental transition was not revealed by four other measures: self-reported (a) ratings of the task stimuli, (b) ratings of naturalistic vignettes of vicarious pain, (c) trait empathy, or neural data from (d) a control neuroimaging task.

DISCUSSION

Findings suggest that at the critical age of around 18, empathy is underpinned by an all-or-none transition from high-alpha power enhancement and functional inhibition to low-alpha power suppression and functional activation in particular brain regions, possibly indicating a marker of maturation in empathic ability. This work advances a recent neurodevelopmental line of studies and provides insight into the functional maturation of empathy at the coming of age.

Another in need enhances prosociality and modulates frontal theta oscillations in young adults

Introduction

Decision-making is a process that can be strongly affected by social factors. Evidence has shown how people deviate from traditional rational-choice predictions under different levels of social interactions. The emergence of prosocial decision-making, defined as any action that is addressed to benefit another individual even at the expense of personal benefits, has been reported as an example of such social influence. Furthermore, brain evidence has shown the involvement of structures such as the prefrontal cortex, anterior insula, and midcingulate cortex during decision settings in which a decision maker interacts with others under physical pain or distress or while being observed by others.

Methods

Using a slightly modified version of the dictator game and EEG recordings, we tested the hypothesis that the inclusion of another person into the decision setting increases prosocial decisions in young adults and that this increase is higher when the other person is associated with others in need. At the brain level, we hypothesized that the increase in prosocial decisions correlates with frontal theta activity.

Results and Discussion

The results showed that including another person in the decision, setting increased prosocial behavior only when this presence was associated with someone in need. This effect was associated with an increase in frontocentral theta-oscillatory activity. These results suggest that the presence of someone in need enhances empathy concerns and norm compliance, raising the participants' prosocial decision-making.

Acetaminophen changes Mu rhythm power related to pain empathy

Empathy is an intricate ability that entails the subjective feeling and understanding of emotions someone else may be experiencing. Acetaminophen, the active ingredient found in Tylenol, is among the most common pain medications consumed. There is new evidence, however, that suggests this common analgesic may also dampen empathic processes. However, no previous study has investigated the effect acetaminophen may have on pain empathy or mu power during a pain empathy task. Therefore, participants were randomly assigned to either an experimental (acetaminophen) or control (sugar) group in a double-blinded experimental research design aimed to measure mu power (using EEG) and behavioral responses to painful and non-painful images. Participants in the experimental group were administered 1000 mg of acetaminophen, and it was verified that participants were unaware which group they were assigned. We found that mu suppression was greater in the acetaminophen group, which was strongest at electrode C3. Additionally, mu power differences between painful and non-painful images were related to trait empathy, and mu power during the painful images were positively correlated with empathy scores. Results from this study suggest that in addition to reducing physical pain, acetaminophen may also change the brain response when perceiving others in pain. The implications of these findings could possibly lead to changes in how we prescribe and administer this common drug.

EEG frequency band analysis in chronic neuropathic pain: A linear and nonlinear approach to classify pain severity

BACKGROUND AND OBJECTIVE

Chronic neuropathic pain (NP) is a chronic pain condition that severely impacts a patient's life. Pain management has proved to be inefficient due to a lack of a simple clinical tool that may identify and monitor NP. A low-cost, noninvasive tool that provides relevant information on NP is the electroencephalogram (EEG). However, the commonly used linear EEG features have proved to be limited in characterizing NP pathophysiology. This study sought to determine whether nonlinear EEG features such as approximate entropy (ApEn) would better differentiate pain severity than absolute band power.

METHODS

A non-parametric statistical approach based on the Brief Pain Inventory (BPI), along with linear and nonlinear EEG features, is proposed in this study. For this purpose, thirty-six chronic NP patients were recruited, and 22 channels were registered. Additionally, a control database of 13 participants with no NP was used as a reference, where 19 channels were registered. For both groups, EEG was recorded for 10 min in a resting state: 5 min with eyes open (EO) and 5 min with eyes closed (EC). Absolute band power and ApEn EEG features in the five clinical frequency bands (delta, theta, alpha, beta, and gamma) were estimated for all channels in both groups. As a result, 220-dimensional and 190-dimensional feature vectors were obtained for experimental and control classes respectively. For the experimental class, NP patients were grouped according to their BPI evaluation in three groups: low, moderate, and high pain. Finally, feature vectors were compared between groups using Kruskal Wallis and post-hoc Dunn's tests.

RESULTS

ApEn revealed significant statistical difference (p <=0.0001) in most frequency bands and conditions among the groups. In contrast, power had less significant differences between groups, particularly with EO. Furthermore, NP groups were notably clustered using only ApEn in theta, alpha, and beta bands.

CONCLUSIONS

The results indicate that ApEn effectively characterizes the different severities of chronic NP rather than the commonly used linear features. ApEn and other nonlinear techniques (e.g., spectral entropy, Shannon entropy) might be a more suitable methodology to monitor chronic NP experience.

Study of EEG alpha wave response on the effects of video-guided deep breathing on pain rehabilitation

BACKGROUND

Athletes with chronic ankle pain (CAP) are more inclined to suffer from physical and psychological pain depending on the severity of the injuries, which might trigger the powerless feeling on future sports participation. Therefore, an efficient and simple method is useful to integrate into conventional physiotherapy (CP) for maintaining mental wellness.

OBJECTIVE

This research aimed to verify the effects and progress of video-guided deep breathing (DB) integrated into CP through study on the changes of alpha waves and pain scale.

METHODS

Alpha waves were recorded using an electroencephalogram (EEG) and a visual analogue scale (VAS) to assess pain intensity before and after the intervention (6 weeks). Thirty CAP participants were recruited and randomly assigned to two groups: group A for video-guided DB integration into their CP and group B for CP. The effects of pre and post intervention were analyzed using a paired t-test with statistical significance set at p< 0.05.

RESULTS

Profound results from the research have shown that the participants who received both the DB+CP revealed a significant increase in alpha wave (p< 0.05) at occipital region.

CONCLUSION

The significant result reveals an increase in alpha waves in the occipital region after 6 weeks and indicates that the video-guided DB with a smartphone application is able to produce a change in CAP participants. This supports the DB integration to the CP for altering the pain perception.

Neuroimaging Assessment of Pain

Pain is an unpleasant sensory and emotional experience. Understanding the neural mechanisms of acute and chronic pain and the brain changes affecting pain factors is important for finding pain treatment methods. The emergence and progress of non-invasive neuroimaging technology can help us better understand pain at the neural level. Recent developments in identifying brain-based biomarkers of pain through advances in advanced imaging can provide some foundations for predicting and detecting pain. For example, a neurologic pain signature (involving brain regions that receive nociceptive afferents) and a stimulus intensity-independent pain signature (involving brain regions that do not show increased activity in proportion to noxious stimulus intensity) were developed based on multivariate modeling to identify processes related to the pain experience. However, an accurate and comprehensive review of common neuroimaging techniques for evaluating pain is lacking. This paper reviews the mechanism, clinical application, reliability, strengths, and limitations of common neuroimaging techniques for assessing pain to promote our further understanding of pain.

The effect of sleep deprivation on empathy for pain: An ERP study

Empathy for pain has a strong adaptive function. It plays a protective role in survival and exerts a vital impact on successful social interaction. Sleep loss, however, is commonplace in current society, and people are increasingly plagued by it. Previous studies have investigated whether sleep loss affects empathy for pain, yet the results were undecided. We aimed to determine whether this effect is existed and further explore the temporal and frequency dynamics of neural activities involved in this effect by recording the electroencephalogram (EEG) signals. We recruited 25 healthy adults (11 females) who were required to perform a pain judgement and unpleasantness rating about the presented nociceptive and neutral pictures after nocturnal sleep (NS) and sleep deprivation (SD), and their neuronal activities were recorded by event-related potentials (ERPs). Results showed a significantly decreased amplitude in the early components (N2, N340) of vicarious pain processing after SD. In further time-frequency (TF) analysis, a reduced energy occurred in theta2 (5-7 Hz) band under SD condition. Moreover, the decreased theta2 was positively correlated with the subjective ratings of both other's pain and self-unpleasantness only under SD condition. Our results indicated that SD impairs affective sharing of empathy for pain.

Neural shifts in alpha rhythm's dual functioning during empathy

INTRODUCTION

Alpha oscillations are unique in their capacity to relay neuronal information through a dual-process named "gating by inhibition": rhythmic enhancement inhibits task-irrelevant regions while rhythmic suppression engages task-relevant regions in the brain. A social-cognitive process that operates by relying on the suppression of the alpha rhythm in the primary somatosensory cortex (S1) is the ability to generate empathy. This phenomenon has been evidenced in dozens of electrophysiological studies targeting adult human subjects. Yet, recent studies on the neurodevelopment of empathy indicate that in younger age, empathy does not involve alpha suppression in S1 but only enhancement. More interestingly, right before adulthood, this rhythm is still enhanced, but in a remarkable shift, a pattern of suppression emerges. In this registered magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) study, we will capture frequency-decomposed neural activity particularly at the alpha range and its corresponding hemodynamic response and target subjects at around 20 years old as a unique time-window in development that allows investigating in parallel both low-alpha suppression and high-alpha enhancement. We aim to address two questions: (a) Does alpha power suppression in the S1 region during empathy correspond to BOLD increase in this region? (b) What is the functional role of alpha power enhancement during empathy development (BOLD signal increase or decrease)? Addressing these questions will particularly advance knowledge on the process of empathy in the brain, and the way in which it is underpinned by alpha oscillations. Moreover, examining these experimental outcomes can potentially lay the ground for future studies that would further examine the role of alpha oscillations in empathy during the course of development.

METHODS

Brain data of forty healthy individuals close to 20 years old will be recorded in two consecutive MEG and fMRI sessions while subjects observing physical pain versus neutral stimuli. Besides, each participant's subjective experiences wll be measred by questionnaires, interviews and rating of the stimuli.

Increasing Self-Other Similarity Modulates Ethnic Bias in Sensorimotor Resonance to Others' Pain

The tendency to simulate the pain of others within our own sensorimotor systems is a vital component of empathy. However, this sensorimotor resonance is modulated by a multitude of social factors including similarity in bodily appearance, e.g. skin colour. The current study investigated whether increasing self-other similarity via virtual transfer to another colour body reduced ingroup bias in sensorimotor resonance. A sample of 58 white participants was momentarily transferred to either a black or a white body using virtual reality technology. We then employed electroencephalography (EEG) to examine event-related desynchronization (ERD) in the sensorimotor beta (13-23 Hz) oscillations while they viewed black, white, and violet photorealistic virtual agents being touched with a noxious or soft object. While the noxious treatment of a violet agent did not increase beta ERD, amplified beta ERD in response to black agent's noxious vs. soft treatment was found in perceivers transferred to black body. Transfer to the white body dismissed the effect. Further exploratory analysis implied that the pain-related beta ERD occurred only when the agent and the participant were of the same colour. The results suggest that even short-lasting changes in bodily resemblance can modulate sensorimotor resonance to others' perceived pain.

Non-phase-locked alpha oscillations are involved in spontaneous racial categorization of faces

Racial categorization of faces has a notable impact on human behavior, but its neural underpinnings remain unresolved. Previous electroencephalography (EEG) research focused on contributions of phase-locked neural activities to racial categorization of faces. We investigated functional roles of non-phase-locked neural oscillations in spontaneous racial categorization of faces by recording EEG from Chinese adults who performed an individuation task on Asian/White faces in Experiment 1 and on Asian/Black faces in Experiment 2. We quantified neural processes involved in spontaneous racial categorization of faces by examining repetition suppression of non-phase-locked neural oscillations when participants viewed faces of one race presented repeatedly in the same block of trials (repetition condition), or faces of two races presented alternately in the same block of trials (alternating condition). We found decreased power of alpha (9-13 Hz) oscillations in the repetition than alternating conditions at 80-240 ms over frontal-central electrodes induced by White/Black (but not Asian) faces. Moreover, larger repetition suppression of alpha oscillations in response to White/Black (vs. Asian) faces predicted greater implicit negative attitudes toward White/Black faces across individuals. Our findings suggest that non-phase-locked alpha oscillations are engaged in spontaneous racial categorization of faces and are associated with implicit negative attitudes toward other-race faces.

One's Interoception Affects the Representation of Seeing Others' Pain: A Randomized Controlled qEEG Study

Objective

This research demonstrates that interoceptive attentiveness (IA) can modulate cortical oscillations related to the emotional and cognitive representations of observing pain in others.

Methods

Twenty participants were required to observe painful/nonpainful stimuli in an individual versus the interactive condition during the recording of the electroencephalogram. The sample was divided into experimental (EXP) and control (CTR) groups, and the EXP group was explicitly required to direct the attention on its interoceptive correlates while observing the stimuli.

Results

Mixed repeated measures, analyses of variance, were applied to each EEG frequency band. Significant findings were obtained mainly for theta and beta bands for the two groups. A hemispheric lateralisation effect was found, with right lateralisation of the theta band for the EXP group when observing painful stimuli and enhanced left activation of theta and beta bands for the CTR group when observing nonpainful stimuli. For both groups, frontal cortical regions were significantly sensitive to social scenarios, while posterior parietal activation was found for stimuli depicting the individual condition.

Conclusions

The results suggest that IA might enhance the emotional representation of painful stimuli, highlighting their negative and unpleasant features in the EXP group, while the attention of the CTR group was mainly drawn to nonpainful stimuli in social and individual conditions, with a positive valence. The role of frontal regions in the processing of social stimuli through social cognition, inducing emotional mirroring and requiring deeper analysis of the social context, was underlined. We propose that IA could be trained for promoting emotion regulation and empathic response.

Neural dynamics of pain expression processing: Alpha-band synchronization to same-race pain but desynchronization to other-race pain

Both electroencephalography and functional magnetic resonance imaging studies have revealed enhanced neural responses to perceived pain in same-race than other-race individuals. However, it remains unclear how neural responses in the sensorimotor, cognitive, and affective subsystems vary dynamically in the first few hundreds of milliseconds to generate racial ingroup favoritism in empathy for pain. We recorded magnetoencephalography signals to pain and neutral expressions of Asian and white faces from Chinese adults during judgments of racial identity of each face. We found that pain compared to neutral expressions of same-race faces induced early increased alpha oscillations in the precuneus/parietal cortices followed by increased alpha-band oscillations in the left anterior insula and temporoparietal junction. Pain compared to neutral expressions of other-race faces, however, induced early suppression of alpha-band oscillations in the bilateral sensorimotor cortices and left insular cortex. Moreover, decreased functional connectivity between the left sensorimotor cortex and left anterior insula predicted reduced subjective feelings of other-race suffering. Our results unraveled distinct patterns of modulations of neural dynamics of sensorimotor, affective, and cognitive components of empathy by interracial relationships between an observer and a target person, which provide possible brain mechanisms for understanding racial ingroup favoritism in social behavior.

The linkage between first-hand pain sensitivity and empathy for others' pain: Attention matters

Many studies suggested shared psychological and neural representations for first-hand physical pain and empathy for others' pain, both of which depend strongly upon top-down controlled mechanisms such as attention. This study aimed to assess the interindividual variation in first-hand physical pain and empathy for pain, and whether their relationship is dependent upon attention. We recruited participants exhibiting high and low sensitivity to first-hand pain (HPS and LPS), and adopted pain empathy paradigms involving attention directed toward or withdrawn from pain of another. Relative to the LPS group, participants in the HPS group estimated greater pain intensity experienced by others, felt greater unpleasantness when viewing others in pain, and exhibited greater sensitivity in discriminating others' pain. Electroencephalographic data showed that when attention was directed toward others' pain, only participants in the HPS group exhibited significant pain empathic effects on the N1 component of event-related potentials and on the α-oscillation response. These empathic neural responses mediated the linkage between first-hand pain sensitivity and empathic behavioral responses. Nevertheless, empathic responses were comparable between two groups when attention was withdrawn from others' pain. These results demonstrate a shared sensitivity to first-hand pain and empathy for pain provided that attention is directed toward pain.

Differences between empathy for face and body pain: Cognitive and neural responses

Empathy for pain is a hotspot in the field of empathy research because of its specific cognitive and neural mechanism. Currently, studies of empathy for pain can be classified into two categories based on the body regions receiving the painful stimulus, i.e., empathy for face pain and empathy for body pain, which conveys painful information based on individuals’ faces or body parts, respectively. Although the existing evidence revealed differences between these two kinds of pain empathy regarding the underlying cognitive and neural mechanisms, the current studies tend to confuse these findings. Therefore, we summarized the differences between empathy for face and body pain, mainly regarding the behavioral reactivity tendency, brain activations, and electrophysiological (EEG) signals. These differences probably stem from the fact that the human face contains more emotional information, while other body parts contain more perceptual information. Thus, future studies should identify the distinctions between empathy for face and body pain, to explore further how empathy for face pain is affected by the facial information of others and focus on empathy for face pain in individuals with psychopathological disorders. Furthermore, the specific reasons for these distinctions and their underlying neuromechanisms deserve to be further reviewed.

When gratitude and cooperation between friends affect inter-brain connectivity for EEG

Background

Recently several studies in the psychological and social field have investigated the social function of gift exchange as a useful way for the consolidation of interpersonal and social relationships and the implementation of prosocial behaviors. Specifically, the present research wanted to explore if gift exchange, increased emotional sharing, gratitude and interpersonal cooperation, leading to an improvement in cognitive and behavioral performance. In this regard, neural connectivity and cognitive performance of 14 pairs of friends were recorded during the development of a joint attention task that involved a gift exchange at the beginning or halfway through the task. The moment of gift exchange was randomized within the pairs: for seven couples, it happened at task beginning, for the remaining seven later. Individuals’ simultaneous brain activity was recorded through the use of two electroencephalograms (EEG) systems that were used in hyperscanning.

Results

The results showed that after gift exchange there was an improvement in behavioral performance in terms of accuracy. For what concerns EEG, instead, an increase of delta and theta activation was observed in the dorsolateral prefrontal cortex (DLPFC) when gift exchange occurred at the beginning of the task. Furthermore, an increase in neural connectivity for delta and theta bands was observed.

Conclusion

The present research provides a significant contribution to the exploration of the factors contributing to the strengthening of social bonds, increasing cooperation, gratitude and prosocial behavior.

The Use of Hyperscanning to Investigate the Role of Social, Affective, and Informative Gestures in Non-Verbal Communication. Electrophysiological (EEG) and Inter-Brain Connectivity Evidence

Communication can be considered as a joint action that involves two or more individuals transmitting different information. In particular, non-verbal communication involves body movements used to communicate different information, characterized by the use of specific gestures. The present study aims to investigate the electrophysiological (EEG) correlates underlying the use of affective, social, and informative gestures during a non-verbal interaction between an encoder and decoder. From the results of the single brain and inter-brain analyses, an increase of frontal alpha, delta, and theta brain responsiveness and inter-brain connectivity emerged for affective and social gestures; while, for informative gestures, an increase of parietal alpha brain responsiveness and alpha, delta, and theta inter-brain connectivity was observed. Regarding the inter-agents' role, an increase of frontal alpha activity was observed in the encoder compared to the decoder for social and affective gestures. Finally, regarding gesture valence, an increase of theta brain responsiveness and theta and beta inter-brain connectivity was observed for positive gestures on the left side compared to the right one. This study, therefore, revealed the function of the gesture type and valence in influencing individuals' brain responsiveness and inter-brain connectivity, showing the presence of resonance mechanisms underlying gesture execution and observation.

Neural mechanisms of reinforcement learning under mortality threat

Reinforcement learning - to adjust behaviors in response to feedback regarding reward and punishment - is pivotal to our survival. The present work investigated whether and how reinforcement learning is affected by thoughts of mortality that endanger one's survival. We recorded electroencephalographic while adults performed a probabilistic learning task that required a forced-choice between two visual patterns for monetary reward for different beneficiaries (i.e., self, stranger, or no one) followed by reward or no-reward feedback. We found that verbal reminders of mortality (vs. negative emotion) enlarged an early positive component (P1) at the occipital electrodes but decreased a late positive potential (LPP) at the frontocentral electrodes in response to learning stimuli. While no-reward feedback relative to reward feedback stimuli elicited a feedback-related negativity (FRN) and increased non-phase locked theta band (4-8 Hz) activity at the frontocentral electrodes during reward learning for all beneficiaries, verbal reminders of mortality (vs. negative emotion) significantly reduced the FRN amplitude but failed to modulate the theta band activity. These results suggest that mortality salience enhances early attentional processing but dampens late cognitive evaluation of the learning stimuli during reinforcement learning. Moreover, mortality salience decreases the neural sensitivity to feedback signaling the absence of monetary reward.

Clarifying the relationship between trait empathy and action-based resonance indexed by EEG mu-rhythm suppression

Sensorimotor resonance, the vicarious activation of the sensory motor system during observation of another's actions, is thought to contribute to important social functions including empathy. Previous research has shown that sensorimotor resonance, as measured by suppression of the electrophysiological (EEG) mu rhythm, is predicted by trait empathy, but findings are inconsistent. Here we report data from a high-powered study (N = 252) to clarify the relationship between sensorimotor resonance as indexed by mu suppression during action observation and trait empathy as measured by the well-established Interpersonal Reactivity Index (IRI). Our initial pre-registered analyses at central electrode locations indicate that sensorimotor resonance is unrelated to general trait empathy or its sub-facets, however, these effects could not be isolated from attention-related occipital alpha. An additional non-registered analysis using Independent Component Analysis (ICA) to look at the isolated central mu-component clarified the relationship. Results confirmed the lack of a relationship between the mu-component and the perspective taking, personal distress, or fantasy facets of the IRI, but suggest a possible association with empathic concern such that greater resonance is associated with greater empathic concern. These results question the previously assumed relationship between trait empathy and sensorimotor resonance and highlight the need to investigate experience sharing tendencies in the context of simulation-based resonance.

Chronic trauma impairs the neural basis of empathy in mothers: Relations to parenting and children's empathic abilities

Early life stress carries long-term negative consequences for children's well-being and maturation of the social brain. Here, we utilize a unique cohort to test its effects on mothers' social brain, targeting mothers' neural empathic response in relation to caregiving and child empathic abilities. Mother-child dyads living in a zone of repeated war-related trauma were followed from early childhood and mother-child behavioral synchrony was repeatedly observed. At pre-adolescence(11-13 years) children's empathic abilities were assessed and mothers(N = 88, N = 44 war-exposed) underwent magnetoencephalography(MEG) while exposed to vicarious pain. All mothers showed alpha suppression in sensorimotor regions, indicating automatic response to others' pain. However, trauma-exposed mothers did not exhibit gamma oscillations in viceromotor cortex, a neural marker of mature empathy which utilizes interoceptive mechanisms for higher-order understanding and does not emerge before adulthood. Mother-child synchrony across the first decade predicted mothers' viceromotor gamma, and both synchrony and maternal viceromotor gamma mediated the relations between war-exposure and child empathic abilities, possibly charting a cross-generational pathway from mothers' mature neural empathy to children's empathic capacities. Our findings are first to probe the maternal social brain in adolescence in relation to parenting and underscore the need for targeted interventions to mothers raising children in contexts of chronic stress.

The Neural Basis of Empathy and Empathic Behavior in the Context of Chronic Trauma

Background: Accumulating evidence in social neuroscience suggests that mature human empathy relies on the integration of two types of processes: a lower-order process mainly tapping into automatic and sensory mechanisms and a higher-order process involving affect and cognition and modulated by top-down control. Studies have also indicated that neural measures of empathy often correlate with behavioral measures of empathy. Yet, little is known on the effects of chronic trauma on the neural and behavioral indices of empathy and the associations among them. Methods: Mothers exposed to chronic war-related trauma and nonexposed controls (N = 88, N = 41 war-exposed) underwent magnetoencephalography (MEG) while watching stimuli depicting vicarious emotional distress. Maternal empathic behavior was assessed during mother-child interaction involving a joint task. Results: Empathy-evoking vignettes elicited response in alpha rhythms in a network involving both sensorimotor and viceromotor (anterior insula) regions, suggesting integration of the sensory and affective components of empathy. Whereas exposure to chronic stress did not affect the level of neural activations in this network, it reduced maternal empathic behavior. Furthermore, trauma exposure impaired the coherence of brain and behavior; only among controls, but not among trauma-exposed mothers, the neural basis of empathy was predicted by maternal empathic behavior. Conclusions: Chronic stress takes a toll on the mother's empathic ability and indirectly impacts the neural basis of empathy by disrupting the coherence of brain and behavior.

Chronic stress increases pain sensitivity via activation of the rACC-BLA pathway in rats

Exposure to chronic stress can produce maladaptive neurobiological changes in pathways associated with pain processing, which may cause stress-induced hyperalgesia (SIH). However, the underlying mechanisms still remain largely unknown. In previous studies, we have reported that the amygdala is involved in chronic forced swim (FS) stress-induced depressive-like behaviors and the exacerbation of neuropathic pain in rats, of which, the basolateral amygdala (BLA) and the central nucleus of the amygdala (CeA) are shown to play important roles in the integration of affective and sensory information including nociception. Here, using in vivo multichannel recording from rostal anterior cingulate cortex (rACC) and BLA, we found that chronic FS stress (CFSS) could increase the pain sensitivity of rats in response to low intensity innoxious stimuli (LIS) and high intensity noxious stimuli (HNS) imposed upon the hindpaw, validating the occurrence of SIH in stressed rats. Moreover, we discovered that CFSS not only induced an increased activity of rACC neuronal population but also produced an augmented field potential power (FPP) of rACC local field potential (LFP), especially in low frequency theta band as well as in high frequency low gamma band ranges, both at the baseline state and under LIS and HNS conditions. In addition, by using a cross-correlation method and a partial directed coherence (PDC) algorithm to analyze the LFP oscillating activity in rACC and BLA, we demonstrated that CFSS could substantially promote the synchronization between rACC and BLA regions, and also enhanced the neural information flow from rACC to BLA. We conclude that exposure of chronic FS stress to rats could result in an increased activity of rACC neuronal population and promote the functional connectivity and the synchronization between rACC and BLA regions, and also enhance the pain-related neural information flow from rACC to BLA, which likely underlie the pathogenesis of SIH.

Do Brain Oscillations Orchestrate Memory?

Rhythmicity and oscillations are common features in nature, and can be seen in phenomena such as seasons, breathing, and brain activity. Despite the fact that a single neuron transmits its activity to its neighbor through a transient pulse, rhythmic activity emerges from large population-wide activity in the brain, and such rhythms are strongly coupled with the state and cognitive functions of the brain. However, it is still debated whether the oscillations of brain activity actually carry information. Here, we briefly introduce the biological findings of brain oscillations, and summarize the recent progress in understanding how oscillations mediate brain function. Finally, we examine the possible relationship between brain cognitive function and oscillation, focusing on how oscillation is related to memory, particularly with respect to state-dependent memory formation and memory retrieval under specific brain waves. We propose that oscillatory waves in the neocortex contribute to the synchronization and activation of specific memory trace ensembles in the neocortex by promoting long-range neural communication.

Functional EEG connectivity during competition

Background

Social behavior and interactions pervasively shape and influence our lives and relationships. Competition, in particular, has become a core topic in social neuroscience since it stresses the relevance and salience of social comparison processes between the inter-agents that are involved in a common task. The majority of studies, however, investigated such kind of social interaction via one-person individual paradigms, thus not taking into account relevant information concerning interdependent participants’ behavioral and neural responses. In the present study, dyads of volunteers participated in a hyperscanning paradigm and competed in a computerized attention task while their electrophysiological (EEG) activity and performance were monitored and recorded. Behavioral data and inter-brain coupling measures based on EEG frequency data were then computed and compared across different experimental conditions: a control condition (individual task, t0), a first competitive condition (pre-feedback condition, t1), and a second competitive condition following a positive reinforcing feedback (post-feedback condition, t2).

Results

Results showed that during competitive tasks participants’ performance was improved with respect to control condition (reduced response times and error rates), with a further specific improvement after receiving a reinforcing feedback. Concurrently, we observed a reduction of inter-brain functional connectivity (primarily involving bilateral prefrontal areas) for slower EEG frequency bands (delta and theta). Finally, correlation analyses highlighted a significant association between cognitive performance and inter-brain connectivity measures.

Conclusions

The present results may help identifying specific patterns of behavioral and inter-brain coupling measures associated to competition and processing of social reinforcements.

Multiple-Brain Connectivity During Third Party Punishment: an EEG Hyperscanning Study

Compassion is a particular form of empathic reaction to harm that befalls others and is accompanied by a desire to alleviate their suffering. This altruistic behavior is often manifested through altruistic punishment, wherein individuals penalize a deprecated human’s actions, even if they are directed toward strangers. By adopting a dual approach, we provide empirical evidence that compassion is a multifaceted prosocial behavior and can predict altruistic punishment. In particular, in this multiple-brain connectivity study in an EEG hyperscanning setting, compassion was examined during real-time social interactions in a third-party punishment (TPP) experiment. We observed that specific connectivity patterns were linked to behavioral and psychological intra- and interpersonal factors. Thus, our results suggest that an ecological approach based on simultaneous dual-scanning and multiple-brain connectivity is suitable for analyzing complex social phenomena.

Brain-to-brain coupling during handholding is associated with pain reduction

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpersonal touch and tests the involvement of interbrain synchrony in pain alleviation. Romantic partners were assigned the roles of target (pain receiver) and observer (pain observer) under pain-no-pain and touch-no-touch conditions concurrent with EEG recording. Brain-to-brain coupling in alpha-mu band (8-12 Hz) was estimated by a three-step multilevel analysis procedure based on running window circular correlation coefficient and post hoc power of the findings was calculated using simulations. Our findings indicate that hand-holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the right hemisphere of the pain observer. Moreover, brain-to-brain coupling in this network was found to correlate with analgesia magnitude and observer's empathic accuracy. These findings indicate that brain-to-brain coupling may be involved in touch-related analgesia.

Disrupted Resting State Network of Fibromyalgia in Theta frequency

Fibromyalgia (FM), chronic widespread pain, exhibits spontaneous pain without external stimuli and is associated with altered brain activities during resting state. To understand the topological features of brain network in FM, we employed persistent homology which is a multiple scale network modeling framework not requiring thresholding. Spontaneous magnetoencephalography (MEG) activity was recorded in 19 healthy controls (HCs) and 18 FM patients. Barcode, single linkage dendrogram and single linkage matrix were generated based on the proposed modeling framework. In theta band, the slope of decrease in the number of connected components in barcodes showed steeper in HC, suggesting FM patients had decreased global connectivity. FM patients had reduced connectivity within default mode network, between middle/inferior temporal gyrus and visual cortex. The longer pain duration was correlated with reduced connectivity between inferior temporal gyrus and visual cortex. Our findings demonstrated that the aberrant resting state network could be associated with dysfunction of sensory processing in chronic pain. The spontaneous nature of FM pain may accrue to disruption of resting state network.

Cooperate or not cooperate EEG, autonomic, and behavioral correlates of ineffective joint strategies

Introduction

The neural activity in response to ineffective joint actions was explored in the present study. Subjects involved in a cooperative but frustrating task (poor performance as manipulated by an external feedback) were required to cooperate (T1) during an attentional task in a way to synchronize their responses and obtain better outcomes.

Methods

We manipulated their strategies by providing false feedbacks (T2) signaling the incapacity to create a synergy, which was reinforced by a general negative evaluation halfway through the game. A control condition was provided (no cooperation required, T0) as well as a check for possible learning effect (time series analysis). The effects of the feedback in modulating subjects' behavioral performance and electrocortical activity were explored by means of brain oscillations (delta, theta, alpha, beta) and autonomic activity (heart rate, HR; skin conductance activity, SCR).

Results

Results showed a specific pattern of behavioral, neural, and peripheral responses after the social feedback. In fact, within this condition, worse behavioral outcomes emerged, with longer response times with respect to the prefeedback one. In parallel, a specific right-lateralized effect was observed over the dorsolateral prefrontal cortex (DLPFC), with increased delta and theta power compared to the previous condition. Moreover, increased SCR was observed with respect to the first part.

Conclusions

Two interpretations are put forward to explain the present findings: 1) the contribution of negative emotions in response to failing interactions or 2) a motivational disengagement toward goal-oriented cooperation elicited by frustrating evaluations.

Frequency-dependent changes in sensorimotor and pain affective systems induced by empathy for pain

Background

Empathy for pain helps us to understand the pain of others indirectly. To better comprehend the processing of empathic pain, we report the frequency-dependent modulation of cortical oscillations induced by watching movies depicting pain using high-density electroencephalography (EEG), magnetoencephalography (MEG), and motor evoked potentials (MEP).

Methods

Event-related desynchronization of EEG and MEG was assessed while participants viewed videos of painful (needle) or neutral (cotton swab) situations. The amplitudes of MEPs were also compared between the needle and cotton swab conditions.

Results

The degree of suppression in α/β band power was significantly increased, whereas that of γ band power was significantly decreased, in the needle condition compared with the cotton swab condition. EEG revealed that significant differences in α/β band were distributed in the right frontocentral and left parietooccipital regions, whereas significant γ band differences were distributed predominantly over the right hemisphere, which were confirmed by source estimation using MEG. There was a significant positive correlation between the difference in γ power of the two conditions and the visual analog scale subjective rating of aversion, but not in the α/β band. The amplitude of MEPs decreased in the needle condition, which confirmed the inhibition of the primary motor cortex.

Conclusion

MEP suppression supports that modulation of cortical oscillations by viewing movies depicting pain involves sensorimotor processing. Our results suggest that α/β oscillations underlie the sensory qualities of others’ pain, whereas the γ band reflects the cognitive aspect. Therefore, α/β and γ band oscillations are differentially involved in empathic pain processing under the condition of motor cortical suppression.

Empathy during consoling touch is modulated by mu-rhythm: An EEG study

The aim of the present study was to examine the mechanisms of empathy for pain that contribute to consoling touch, a distress-alleviating contact behavior carried out by an observer in response to the suffering of a target. We tested romantic couples in a paradigm that involves consoling touch and examined the attenuation of the mu/alpha rhythm (8-13Hz) in the consoling partner. During the task, the toucher either held the consoled partner's right hand (human touch) or held onto the armrest of the chair (non-human touch), while the consoled partner experienced inflicted pain (pain condition) or did not experience any pain (no-pain condition). In accordance with our hypotheses, the results revealed an interaction between touch and pain at in mu/alpha rhythms in all central sites (C3, C4, Cz). Specifically, we found that the toucher's mu suppression was higher in the consoling touch condition, i.e., while touching the partner who is in pain, compared to the three control conditions. Additionally, we found that in the consoling touch condition, mu suppression at electrode C4 of the toucher correlated with a measure of situational empathy. Our findings suggest that electrophysiological and behavioral measures that have been associated with empathy for pain are modulated during consoling touch.

Empathy in Negative and Positive Interpersonal Interactions. What is the Relationship Between Central (EEG, fNIRS) and Peripheral (Autonomic) Neurophysiological Responses?

Emotional empathy is crucial to understand how we respond to interpersonal positive or negative situations. In the present research, we aim at identifying the neural networks and the autonomic responsiveness underlying the human ability to perceive and empathize with others' emotions when positive (cooperative) or negative (uncooperative) interactions are observed. A multimethodological approach was adopted to elucidate the reciprocal interplay of autonomic (peripheral) and central (cortical) activities in empathic behavior. Electroencephalography (EEG, frequency band analysis) and hemodynamic (functional Near-Infrared Spectroscopy, fNIRS) activity were all recorded simultaneously with systemic skin conductance response (SCR) and heart rate (HR) measurements as potential biological markers of emotional empathy. Subjects were required to empathize in interpersonal interactions. As shown by fNIRS/EEG measures, negative situations elicited increased brain responses within the right prefrontal cortex (PFC), whereas positive situations elicited greater responses within the left PFC. Therefore, a relevant lateralization effect was induced by the specific valence (mainly for negative conditions) of the emotional interactions. Also, SCR was modulated by positive/negative conditions. Finally, EEG activity (mainly low-frequency theta and delta bands) intrinsically correlated with the cortical hemodynamic responsiveness, and they both predicted autonomic activity. The integrated central and autonomic measures better elucidated the significance of empathic behavior in interpersonal interactions.

Maternal Depression Across the First Years of Life Impacts the Neural Basis of Empathy in Preadolescence

OBJECTIVE

Exposure to maternal depression across the first years of life markedly increases children's susceptibility to psychopathology, yet no study has tested its effects on the maturation of children's social brain.

METHOD

Using a birth cohort of mothers with no contextual risk (N = 1,983), families were followed at 7 time points from birth to 11 years and repeatedly assessed for maternal depression across the first 6 years to form 2 cohorts: mothers continuously depressed from birth to 6 years and controls without depression. At 11 years of age, children's (n = 72; depressed, n = 27; nondepressed, n = 45) brain response to others' pain was measured by magnetoencephalography.

RESULTS

Preadolescents displayed a unique oscillatory pattern with higher alpha power to pain versus no pain expressing as alpha rebound, not alpha suppression, at a late time window (1,100-1,300 ms post-stimulus) in the supplementary motor area. This suggests that top-down processing in areas of the pain matrix can underpin the maturation of vicarious empathy. Children of mothers with depression showed enhanced alpha rebound to pain in the right posterior superior temporal gyrus, which was unrelated to emotion detection abilities, pointing to decreased late processing of others' overwhelming experiences in socio-cognitive areas. Alpha power in the posterior superior temporal gyrus was predicted by higher maternal intrusiveness and lower synchrony across early childhood.

CONCLUSION

These findings, from the first study to examine maternal depression and early caregiving as long-term predictors of children's neural empathic response, pinpoint a decrease in top-down socio-cognitive mechanisms as potential pathways for the cross-generational transfer of vulnerability from mothers with depression to their offspring and highlight the need for early interventions focused on enhancing maternal attunement.

Oxytocin enhances inter-brain synchrony during social coordination in male adults

Recent brain imaging research has revealed oxytocin (OT) effects on an individual's brain activity during social interaction but tells little about whether and how OT modulates the coherence of inter-brain activity related to two individuals' coordination behavior. We developed a new real-time coordination game that required two individuals of a dyad to synchronize with a partner (coordination task) or with a computer (control task) by counting in mind rhythmically. Electroencephalography (EEG) was recorded simultaneously from a dyad to examine OT effects on inter-brain synchrony of neural activity during interpersonal coordination. Experiment 1 found that dyads showed smaller interpersonal time lags of counting and greater inter-brain synchrony of alpha-band neural oscillations during the coordination (vs control) task and these effects were reliably observed in female but not male dyads. Moreover, the increased alpha-band inter-brain synchrony predicted better interpersonal behavioral synchrony across all participants. Experiment 2, using a double blind, placebo-controlled between-subjects design, revealed that intranasal OT vs placebo administration in male dyads improved interpersonal behavioral synchrony in both the coordination and control tasks but specifically enhanced alpha-band inter-brain neural oscillations during the coordination task. Our findings provide first evidence that OT enhances inter-brain synchrony in male adults to facilitate social coordination.

Biological Computation Indexes of Brain Oscillations in Unattended Facial Expression Processing Based on Event-Related Synchronization/Desynchronization

Estimation of human emotions from Electroencephalogram (EEG) signals plays a vital role in affective Brain Computer Interface (BCI). The present study investigated the different event-related synchronization (ERS) and event-related desynchronization (ERD) of typical brain oscillations in processing Facial Expressions under nonattentional condition. The results show that the lower-frequency bands are mainly used to update Facial Expressions and distinguish the deviant stimuli from the standard ones, whereas the higher-frequency bands are relevant to automatically processing different Facial Expressions. Accordingly, we set up the relations between each brain oscillation and processing unattended Facial Expressions by the measures of ERD and ERS. This research first reveals the contributions of each frequency band for comprehension of Facial Expressions in preattentive stage. It also evidences that participants have emotional experience under nonattentional condition. Therefore, the user's emotional state under nonattentional condition can be recognized in real time by the ERD/ERS computation indexes of different frequency bands of brain oscillations, which can be used in affective BCI to provide the user with more natural and friendly ways.

Neural oscillations in antipsychotic-naïve patients with a first psychotic episode

OBJECTIVES

In chronic schizophrenic psychoses, oscillatory abnormalities predominantly occur in prefrontal cortical regions and are associated with reduced communication across cortical areas. Nevertheless, it remains unclear whether similar alterations can be observed in patients with a first episode of psychosis (FEP), a state characterised by pathological features occurring in both late prodromal patients and initial phases of frank schizophrenic psychoses.

METHODS

We assessed resting-state electroencephalographic data of 31 antipsychotic-naïve FEP patients and 29 healthy controls (HC). We investigated the three-dimensional (3D) current source density (CSD) distribution and lagged phase synchronisation (LPS) of oscillations across small-scale and large-scale brain networks. We additionally investigated LPS relationships with clinical symptoms using linear mixed-effects models.

RESULTS

Compared to HC, FEP patients demonstrated abnormal CSD distributions in frontal areas of the brain; while decreased oscillations were found in the low frequencies, an increase was reported in the high frequencies (P < 0.01). Patients also exhibited deviant LPS in the high frequencies, whose dynamics changed over increasing 3D cortico-cortical distances and increasing psychotic symptoms.

CONCLUSIONS

These results indicate that in addition to prefrontal cortical abnormalities, altered synchronised neural oscillations are also present, suggesting possible disruptions in cortico-cortical communications. These findings provide new insights into the pathophysiological mechanisms of emerging schizophrenic psychoses.

EEG Oscillation Evidences of Enhanced Susceptibility to Emotional Stimuli during Adolescence

Background: Our recent event-related potential (ERP) study showed that adolescents are more emotionally sensitive to negative events compared to adults, regardless of the valence strength of the events. The current work aimed to confirm this age-related difference in response to emotional stimuli of diverse intensities by examining Electroencephalography (EEG) oscillatory power in time-frequency analysis.

Methods: Time-frequency analyses were performed on the EEG data recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults during a covert emotional task. The results showed a significant age by emotion interaction effect in the theta and beta oscillatory power during the 500–600 ms post stimulus.

Results: Adolescents showed significantly less pronounced theta synchronization (ERS, 5.5–7.5 Hz) for HN stimuli, and larger beta desynchronization (ERD; 18–20 Hz) for both HN and MN stimuli, in comparison with neutral stimuli. By contrast, adults exhibited no significant emotion effects in theta and beta frequency bands. In addition, the analysis of the alpha spectral power (10.5–12 Hz; 850–950 ms) showed a main effect of emotion, while the emotion by age interaction was not significant. Irrespective of adolescents or adults, HN and MN stimuli elicited enhanced alpha suppression compared to Neutral stimuli, while the alpha power was similar across HN and MN conditions.

Conclusions: These results confirmed prior findings that adolescents are more sensitive to emotionally negative stimuli compared to adults, regardless of emotion intensity, possibly due to the developing prefrontal control system during adolescence.

Behavioral and EEG Evidence for Auditory Memory Suppression

The neural basis of motivated forgetting using the Think/No-Think (TNT) paradigm is receiving increased attention with a particular focus on the mechanisms that enable memory suppression. However, most TNT studies have been limited to the visual domain. To assess whether and to what extent direct memory suppression extends across sensory modalities, we examined behavioral and electroencephalographic (EEG) effects of auditory TNT in healthy young adults by adapting the TNT paradigm to the auditory modality. Behaviorally, suppression of memory strength was indexed by prolonged response time (RTs) during the retrieval of subsequently remembered No-Think words. We examined task-related EEG activity of both attempted memory retrieval and inhibition of a previously learned target word during the presentation of its paired associate. Event-related EEG responses revealed two main findings: (1) a centralized Think > No-Think positivity during auditory word presentation (from approximately 0-500 ms); and (2) a sustained Think positivity over parietal electrodes beginning at approximately 600 ms reflecting the memory retrieval effect which was significantly reduced for No-Think words. In addition, word-locked theta (4-8 Hz) power was initially greater for No-Think compared to Think during auditory word presentation over fronto-central electrodes. This was followed by a posterior theta increase indexing successful memory retrieval in the Think condition. The observed event-related potential pattern and theta power analysis are similar to that reported in visual TNT studies and support a modality non-specific mechanism for memory inhibition. The EEG data also provide evidence supporting differing roles and time courses of frontal and parietal regions in the flexible control of auditory memory.