Neural oscillations dissociate between self-related attentional orientation versus evaluation

Causal role of frontocentral beta oscillation in comprehending linguistic communicative functions

Linguistic communication is often considered as an action serving the function of conveying the speaker's goal to the addressee. Although neuroimaging studies have suggested a role of the motor system in comprehending communicative functions, the underlying mechanism is yet to be specified. Here, by two EEG experiments and a tACS experiment, we demonstrate that the frontocentral beta oscillation, which represents action states, plays a crucial part in linguistic communication understanding. Participants read scripts involving two interlocutors and rated the interlocutors' attitudes. Each script included a critical sentence said by the speaker expressing a context-dependent function of either promise, request, or reply to the addressee's query. These functions were behaviorally discriminated, with higher addressee's will rating for the promise than for the reply and higher speaker's will rating for the request than for the reply. EEG multivariate analyses showed that different communicative functions were represented by different patterns of the frontocentral beta activity but not by patterns of alpha activity. Further tACS results showed that, relative to alpha tACS and sham stimulation, beta tACS improved the predictability of communicative functions of request or reply, as measured by the speaker's will rating. These results convergently suggest a causal role of the frontocentral beta activities in comprehending linguistic communications.

Identification of Optimal and Most Significant Event Related Brain Functional Network

Advancements in network science have facilitated the study of brain communication networks. Existing techniques for identifying event-related brain functional networks (BFNs) often result in fully connected networks. However, determining the optimal and most significant network representation for event-related BFNs is crucial for understanding complex brain networks. The presence of both false and genuine connections in the fully connected network requires network thresholding to eliminate false connections. However, a generalized framework for thresholding in network neuroscience is currently lacking. To address this, we propose four novel methods that leverage network properties, energy, and efficiency to select a generalized threshold level. This threshold serves as the basis for identifying the optimal and most significant event-related BFN. We validate our methods on an openly available emotion dataset and demonstrate their effectiveness in identifying multiple events. Our proposed approach can serve as a versatile thresholding technique to represent the fully connected network as an event-related BFN.

The oscillatory fingerprints of self-prioritization: Novel markers in spectral EEG for self-relevant processing

Self-prioritization is a very influential modulator of human information processing. Still, little is known about the time-frequency dynamics of the self-prioritization network. In this EEG study, we used the familiarity-confound free matching task to investigate the spectral dynamics of self-prioritization and their underlying cognitive functions in a drift-diffusion model. Participants (N = 40) repeatedly associated arbitrary geometric shapes with either "the self" or "a stranger." Behavioral results demonstrated prominent self-prioritization effects (SPEs) in reaction time and accuracy. Remarkably, EEG cluster analysis also revealed two significant SPEs, one in delta/theta power (2-7 Hz) and one in beta power (19-29 Hz). Drift-diffusion modeling indicated that beta activity was associated with evidence accumulation, whereas delta/theta activity was associated with response selection. The decreased beta suppression of the SPE might indicate more efficient sensorimotor processing of self-associated stimulus-response features, whereas the increased delta/theta SPE might refer to the facilitated retrieval of self-relevant features across a widely distributed associative self-network. These novel oscillatory biomarkers of self-prioritization indicate their function as an associative glue for the self-concept.

Sense of self in mind and body: an eLORETA-EEG study

The human brain engages the sense of self through both semantic and somatic self-referential processing (SRP). Alpha and theta oscillations have been found to underlie SRP but have not been compared with respect to semantic and somatic SRP. We recorded electroencephalography (EEG) from 50 participants during focused internal attention on life roles (e.g. "friend") and outer body (e.g. "arms") compared to resting state and an external attention memory task and localized the sources of on-scalp alpha (8-12 Hz) and theta (4-8 Hz) EEG signals with exact low-resolution tomography. Logarithm of F-ratios was calculated to compare differences in alpha and theta power between SRP conditions, resting state, and external attention. Results indicated that compared to resting state, semantic SRP induced lower theta in the frontal cortex and higher theta in the parietal cortex, whereas somatic SRP induced lower alpha in the frontal and insula cortex and higher alpha in the parietal cortex. Furthermore, results indicated that compared to external attention, both semantic and somatic SRP induced higher alpha in the dorsolateral prefrontal cortex with lateralized patterns based on task condition. Finally, an analysis directly comparing semantic and somatic SRP indicated frontal-parietal and left-right lateralization of SRP in the brain. Our results suggest the alpha and theta oscillations in the frontal, parietal, and the insula cortex may play crucial roles in semantic and somatic SRP.

Parietal Gamma Band Oscillation Induced by Self-Hand Recognition

Physiological studies have shown that self-body images receive unique recognition processing in a wide range of brain areas, from the frontal lobe to the parietal-occipital cortex. Event-related potential (ERP) studies have shown that the self-referential effect on the image of a hand increases P300 components, but such studies do not evaluate brain oscillatory activity. In this study, we aimed to discover the self-specific brain electrophysiological activity in relation to hand images. ERPs on the fronto-parietal midline were elicited by a three-stimulus visual oddball task using hand images: the self-hand, another hand (most similar to the self-hand), and another hand (similar to the self-hand). We analyzed ERP waveform and brain oscillatory activity by simple averaging and time-frequency analysis. The simple averaging analysis found no significant differences between the responses for the three stimulus tasks in all time windows. However, time-frequency analysis showed that self-hand stimuli elicited high gamma ERS in 650–900 ms at the Cz electrode compared to other hand stimuli. Our results show that brain activity specific to the self-referential process to the self-hand image was reflected in the long latency gamma band activity in the mid-central region. This high gamma-band activity at the Cz electrode may be similar to the activity of the mirror neuron system, which is involved in hand motion.

Performance of healthy persons under pain in different cognitive load tasks: An event-related potential study on experimental pain individuals

OBJECTIVE

This study aims to determine how brain activities underlying task with different cognitive load would be modulated by the painful state using electroencephalography.

METHODS

The pain state was established by spraying capsaicin on subjects' left inner forearm. A total of 20 experimental pain subjects and 20 matched nonpain controls underwent cognitive tasks with electroencephalogram recording. We collected and analyzed behavioral and event-related potential (ERP) data.

RESULTS

High cognitive tasks exhibited significantly longer response times and lower accuracies than low-load tasks. The experimental pain group displayed a significantly lower accuracy than the control group. In addition, the experimental pain group showed no significance between high and low cognitive tasks in early ERP components (amplitude of N1, P2, N2, and early part of late positive potential), whereas the control group exhibited significance between different load tasks. Furthermore, we observed a delay peak energy for delta and theta oscillation in Fz 500-800 ms after the onset for pain persons and high cognitive load tasks.

CONCLUSIONS

Inadequate early attention modulation, along with delayed peak energy for brain oscillation (delta and theta), could be accountable for a worse performance in cognitive tasks in the experimental pain group. Thus, cognitive load is a highly considerable factor. Overall, this study offers more insights into how healthy population works with cognitive tasks under pain neurologically.

The effect of emotional information from eyes on empathy for pain: A subliminal ERP study

Facial expressions are deeply tied to empathy, which plays an important role during social communication. The eye region is effective at conveying facial expressions, especially fear and sadness emotions. Further, it was proved that subliminal stimuli could impact human behavior. This research aimed to explore the effect of subliminal sad, fearful and neutral emotions conveyed by the eye region on a viewer's empathy for pain using event-related potentials (ERP). The experiment used an emotional priming paradigm of 3 (prime: subliminal neutral, sad, fear eye region information) × 2 (target: painful, nonpainful pictures) within-subject design. Participants were told to judge whether the targets were in pain or not. Results showed that the subliminal sad eye stimulus elicited a larger P2 amplitude than the subliminal fearful eye stimulus when assessing pain. For P3 and late positive component (LPC), the amplitude elicited by the painful pictures was larger than the amplitude elicited by the nonpainful pictures. The behavioral results demonstrated that people reacted to targets depicting pain more slowly after the sad emotion priming. Moreover, the subjective ratings of Personal Distress (PD) (one of the dimensions in Chinese version of Interpersonal Reactivity Index scale) predicted the pain effect in empathic neural responses in the N1 and N2 time window. The current study showed that subliminal eye emotion affected the viewer's empathy for pain. Compared with the subliminal fearful eye stimulus, the subliminal sad eye stimulus had a greater impact on empathy for pain. The perceptual level of pain was deeper in the late controlled processing stage.

Taking Familiar Others' Perspectives to Regulate Our Own Emotion: An Event-Related Potential Study

Current research on emotion regulation has mainly focused on Gross’s cognitive strategies for regulating negative emotion; however, little attention has been paid to whether social cognitive processes can be used to regulate both positive and negative emotions. We considered perspective-taking as an aspect of social cognition, and investigated whether it would affect one’s own emotional response. The present study used a block paradigm and event-related potential (ERP) technology to explore this question. A 3 (perspective: self vs. pessimistic familiar other vs. optimistic familiar other) × 3 (valence: positive vs. neutral vs. negative) within-group design was employed. Thirty-six college students participated and considered their own or target others’ feelings about pictures with different valences. Results showed that positive emotional responses were more neutral under a pessimistic familiar other perspective, and more positive under an optimistic familiar other perspective, and vice versa for negative emotional responses. In ERP results, compared with a self-perspective, taking familiar others’ perspectives elicited reductions in P3 (370–410 ms) and LPP (400–800 ms) difference waves. These findings suggested that taking a pessimistic or optimistic familiar other perspective affects emotion regulation by changing later processing of emotional information.

Music induced happy mood suppresses the neural responses to other's pain: Evidences from an ERP study

In the current study, we explored the time course of processing other's pain under induced happy or sad moods. Event-related potentials (ERPs) were recorded when participants observing pictures showing others in painful or non-painful situations. Mood induction procedures were applied to the participants before the picture observation task. Happy and sad moods were induced by listening to about 10 minutes of music excerpts selected from the Chinese Affective Music System (CAMS). The ERP results revealed that the induced mood can influence the early automatic components N1, P2, and N2 but not the later top-down controlled components P3 and LPP. The difference of amplitudes elicited by painful and non-painful stimuli was significantly different only in a sad mood but not in a happy mood, which indicates that comparing to a sad mood, the participants' ability to discriminate the painful stimuli from the non-painful stimuli was weakened in a happy mood. However, this reduction of sensitivity to other's pain in a happy mood does not necessarily reduce the tendency of prosocial behaviors. These findings offer psychophysiological evidences that people's moods can influence their empathic response towards other's pain.

The role of gamma interbrain synchrony in social coordination when humans face territorial threats

Throughout history and into the modern era, human groups have been continually subjected to a wide range of societal threats, from natural disasters to pandemics to terrorism. Yet despite this fundamental aspect of human existence, there has been little research on how societal threat affects social coordination at both the neural and the behavioral level. Here, we show for the first time that individuals are better able to coordinate under high societal threat as compared to low or no threat (Experiment 1). Using a method of hyperscanning electroencephalography (EEG), which simultaneously measures brain activity among interacting subjects, we further illustrate that interbrain synchrony of gamma band oscillations is enhanced when people are under high threat, and increased gamma interbrain synchrony is associated with lower dyadic interpersonal time lag (i.e. higher coordination) (Experiment 2). To our knowledge, the current work provides some of the first empirical evidence that gamma interbrain synchrony is associated with social coordination when humans are under threat.

Evaluation of Cognitive Function When Hearing One's Own Name in Patients With Brain Injuries in Early Developmental Stages

PURPOSE

The level of residual cognitive function in patients with early brain injury is a key factor limiting rehabilitation and the quality of life. Although understanding residual function is necessary for appropriate rehabilitation, the extent of its effects on cognitive improvement remains unknown. This study evaluated cognitive function in patients with severe motor and intellectual disabilities after early brain injuries due to cerebral hemorrhage or periventricular leukomalacia. We focused on neural responses to hearing the subject's own name (SON). According to previous studies, differences in response to SON are associated with several types of cognitive dysfunction.

METHODS

We examined healthy subjects (aged 21.4 ± 1.10 years; control) and patients with a previous brain injury (aged 13-27 years at the time of our analysis) resulting in periventricular leukomalacia or a cerebral hemorrhage during the perinatal period or childhood. We recorded EEG responses to the SON and to other Japanese words, obtaining EEG-evoked potentials with wavelet transformations.

RESULTS

Compared with healthy controls, beta power (not alpha power) revealed differences in response to SON by patients with brain injury, especially those with cerebral hemorrhage.

CONCLUSIONS

We suggest that alpha and beta power differences reflect different cognitive functions and that the SON response reveals more than one process. Beta powers may reflect the intellectual disability of cognitive function in response to self-relevant stimuli, especially in patients with cerebral hemorrhage. Meanwhile, alpha powers did not differ from those of the healthy controls, suggesting that the patients perhaps paid attention to their own names.

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.

EEG correlates of self-referential processing

Self-referential processing has been principally investigated using functional magnetic resonance imaging (fMRI). However, understanding of the brain functioning is not possible without careful comparison of the evidence coming from different methodological domains. This paper aims to review electroencephalographic (EEG) studies of self-referential processing and to evaluate how they correspond, complement, or contradict the existing fMRI evidence. There are potentially two approaches to the study of EEG correlates of self-referential processing. Firstly, because simultaneous registration of EEG and fMRI has become possible, the degree of overlap between these two signals in brain regions related to self-referential processing could be determined. Second and more direct approach would be the study of EEG correlates of self-referential processing per se. In this review, I discuss studies, which employed both these approaches and show that in line with fMRI evidence, EEG correlates of self-referential processing are most frequently found in brain regions overlapping with the default network, particularly in the medial prefrontal cortex. In the time domain, the discrimination of self- and others-related information is mostly associated with the P300 ERP component, but sometimes is observed even earlier. In the frequency domain, different frequency oscillations have been shown to contribute to self-referential processing, with spontaneous self-referential mentation being mostly associated with the alpha frequency band.