N1 Amplitude Research Articles

Study on the event-related potential in recognition of emotional words between typical “five-state personality”

Objective: To explore the event-related potential (ERP) differences of people with typical traditional Chinese medicine (TCM) “five-state personality” in the task of judging the emotional attributes (positive, neutral, and negative) of Chinese words. Methods: The “five-state personality test” was applied to screen the typical TCM “five-state personality”, and three groups were established including positive personality, negative personality, and atypical personality. The differences of electroencephalogram (EEG) components in the task of judging the emotional attributes of Chinese words were collected using ERPs. The 3 personality groups ×3 words with emotional attributes were analyzed by two-way analysis of variance (ANOVA). Results: The N1 and P300 components were induced successfully. The analysis on the mean values of corresponding electrodes in left frontal lobe, right frontal lobe, frontal lobe and parietal lobe showed that in the typical negative personality group, the absolute value of N1 amplitude was smaller in the prefrontal and frontal lobes, and the latency was shorter in the left frontal lobe, while in the typical positive personality group, the absolute value of N1 amplitude was larger in the left frontal lobe. In the prefrontal and frontal lobes, the N1 peak absolute value of negative words was higher and the latency was longer, and the N1 latency of neutral words was shorter. The N1 latency of positive words was shorter in the parietal lobe. In the right frontal and frontal lobes, the P300 peak of negative words was higher and the latency was longer, while the latency of positive words was longer in the parietal lobe. In addition, there was some interaction between personality groups and emotional attributes of words. Conclusion: When people with typical “five-state personality” judge the emotional attributes of words, the absolute value of N1 amplitude in left prefrontal lobe of typical positive personality group is high, while that of typical negative personality group was small and the latency is short. The P300 latency of negative words is longer in the right frontal and frontal lobes, and that of positive words is longer in the parietal lobes, with more significant difference in the positive personality group.

EEG Responses to the Number of Objects in Partially Occluded and Uncovered Scenes.

Perceptual completion is ubiquitous when estimating properties such as the shape, size, or number of objects in partially occluded scenes. Behavioral experiments showed that the number of hidden objects is underestimated in partially occluded scenes compared with an estimation based on the density of visible objects and the amount of occlusion. It is still unknown at which processing level this (under)estimation of the number of hidden objects occurs. We studied this question using a passive viewing task in which observers viewed a game board that was initially partially occluded and later was uncovered to reveal its hidden parts. We simultaneously measured the electroencephalographic responses to the partially occluded board presentation and its uncovering. We hypothesized that if the underestimation is a result of early sensory processing, it would be observed in the activities of P1 and N1, whereas if it is because of higher level processes such as expectancy, it would be reflected in P3 activities. Our data showed that P1 amplitude increased with numerosity in both occluded and uncovered states, indicating a link between P1 and simple stimulus features. The N1 amplitude was highest when both the initially visible and uncovered areas of the board were completely filled with game pieces, suggesting that the N1 component is sensitive to the overall Gestalt. Finally, we observed that P3 activity was reduced when the density of game pieces in the uncovered parts matched the initially visible parts, implying a relationship between the P3 component and expectation mismatch. Overall, our results suggest that inferences about the number of hidden items are reflected in high-level processing.

Neural correlates of trait anxiety in sensory processing and distractor filtering.

Evidence suggests that trait anxiety relates to cognitive processing and behavior. However, the relationships between trait anxiety and sensory processing, goal-directed performance and sensorimotor function are unclear, particularly in a multimodal context. This study used electroencephalography to evaluate whether trait anxiety influenced visual and tactile event-related potentials (ERPs), as well as behavioral distractor cost, in a bimodal sensorimotor task. Twenty-nine healthy young adults completed the State-Trait Anxiety Inventory. Participants were directed to focus on either tactile or visual stimuli while disregarding the other modality, responding to target stimulus amplitude with a proportional grip. Previous research suggests that somatosensory N70 and visual P2 ERPs serve as markers of attentional relevance, with attention also impacting the visual P3 ERP. It was hypothesized that trait anxiety would modulate the ERPs susceptible to attentional modulation (tactile N70, visual P2 and P3) and not affect behavioral performance. Trait anxiety showed a large, significant interaction with attention for visual P3 latency in response to unimodal visual stimuli, with a positive relationship between P3 latencies and trait anxiety when attending toward the stimulus and negative when attending away. A large, positive main effect of trait anxiety on visual N1 amplitude for bimodal stimuli was also detected. As predicted, trait anxiety related to ERPs but not behavioral distractor cost. These findings suggest that trait anxiety modulates visual but not somatosensory processing correlates based on attention. The absence of overt behavioral performance effects suggests compensatory mechanisms may offset underlying differences in sensory processing.

Adaptation patterns and their associations with mismatch negativity: An electroencephalogram (EEG) study with controlled expectations.

Adaptation refers to the decreased neural response that occurs after repeated exposure to a stimulus. While many electroencephalogram (EEG) studies have investigated adaptation by using either single or multiple repetitions, the adaptation patterns under controlled expectations manifested in the two main auditory components, N1 and P2, are still largely unknown. Additionally, although multiple repetitions are commonly used in mismatch negativity (MMN) experiments, it is unclear how adaptation at different time windows contributes to this phenomenon. In this study, we conducted an EEG experiment with 37 healthy adults using a random stimulus arrangement and extended tone sequences to control expectations. We tracked the amplitudes of the N1 and P2 components across the first 10 tones to examine adaptation patterns. Our findings revealed an L-shaped adaptation pattern characterised by a significant decrease in N1 amplitude after the first repetition (N1 initial adaptation), followed by a continuous, linear increase in P2 amplitude after the first repetition (P2 subsequent adaptation), possibly indicating model adjustment. Regression analysis demonstrated that the peak amplitudes of both the N1 initial adaptation and the P2 subsequent adaptation significantly accounted for variance in MMN amplitude. These results suggest distinct adaptation patterns for multiple repetitions across different components and indicate that the MMN reflects a combination of two processes: the initial adaptation in the N1 and a continuous model adjustment effect in the P2. Understanding these processes separately could have implications for models of cognitive processing and clinical disorders.

Fifty Percent of the Time, Tones Come Every Time: Stronger Prediction Error Effects on Neurophysiological Sensory Attenuation for Self-generated Tones.

The N1/P2 amplitude reduction for self-generated tones in comparison to external tones in EEG, which has recently also been described for action observation, is an example of the so-called sensory attenuation. Whether this effect is dependent on motor-based or general predictive mechanisms is unclear. Using a paradigm, in which actions (button presses) elicited tones in only half the trials, this study examined how the processing of the tones is modulated by the prediction error in each trial in a self-performed action compared with action observation. In addition, we considered the effect of temporal predictability by adding a third condition, in which visual cues were followed by external tones in half the trials. The attenuation result patterns differed for N1 and P2 amplitudes, but neither showed an attenuation effect beyond temporal predictability. Interestingly, we found that both N1 and P2 amplitudes reflected prediction errors derived from a reinforcement learning model, in that larger errors coincided with larger amplitudes. This effect was stronger for tones following button presses compared with cued external tones, but only for self-performed and not for observed actions. Taken together, our results suggest that attenuation effects are partially driven by general predictive mechanisms irrespective of self-performed actions. However, the stronger prediction-error effects for self-generated tones suggest that distinct motor-related factors beyond temporal predictability, potentially linked to reinforcement learning, play a role in the underlying mechanisms. Further research is needed to validate these initial findings as the calculation of the prediction errors was limited by the design of the experiment.

A Comparison of Ocular Vestibular Evoked Myogenic Potentials via Audiometric and Nonaudiometric Bone Vibrators.

There is limited evidence demonstrating the ability of audiometric bone vibrators to elicit ocular vestibular evoked myogenic potentials (oVEMPs). The RadioEar B71 bone vibrator has insufficient power output to reliably evoke oVEMPs, which has previously left nonaudiometric and nonmedically approved devices such as the Brüel & Kjær Mini-shaker 4810 as the only feasible alternative. The newer RadioEar B81 model has a higher power output than its predecessor, but evidence for its suitability for eliciting oVEMPs has so far been mixed. This variability may be due to factors other than simply the power output, such as whether sufficient static force is applied to hold the transducer in place and transfer vibratory energy into the bone. This study aimed to test the hypothesis that bone-conducted oVEMPs can be obtained with the B81 that are equivalent to those from the Mini-shaker, the de facto gold-standard transducer for this response, when the outputs of the two transducers are matched and they are coupled with sufficient static force. oVEMPs elicited by both transducers were recorded in a counterbalanced within-groups design. Sixteen healthy adults (12 female; 22-47 years) with no history of hearing, balance, or neurological disorders were included in the study. One-cycle alternating tone-burst stimuli at 500 Hz were delivered to the mastoid from each transducer. The vibratory force levels were matched at 127 dB peak-to-peak equivalent force levels, and both were held in place with a static force around 10 N. oVEMP waveforms were gathered from the contralateral eye using the belly-tendon montage and were assessed for statistical equivalence. There was an absence of any statistically significant difference in N10 and N10-P15 amplitudes in oVEMPs from each transducer. Our results indicate that B81 can elicit oVEMPs with no meaningful differences to those from the Mini-shaker, provided effective stimulus levels are matched and static force is sufficient. Although further work is necessary to investigate equivalence at other stimulus frequencies and stimulation sites, the results support the use of the B81 to elicit 500Hz oVEMPs at the mastoid in a clinical setting.

Unveiling the influence of persuasion strategies on cognitive engagement: an ERPs study on attentional search.

This study aimed to investigate how central versus peripheral persuasion methods, delivered through rational and emotional persuasion strategies, influence cognitive engagement and information processing during visual search tasks. Participants were allocated into four groups based on the media type (video vs. text) and the persuasion route (central vs. peripheral). The early and late stages of attentional processing were examined through the N1, P2, and P3 ERP components. The results demonstrated a pronounced N1 amplitude in response to text-based peripheral persuasion, indicating enhanced early attentional engagement. Additionally, parallel search tasks revealed a larger P3 amplitude for central versus peripheral routes, suggesting significant cognitive resource allocation during tasks requiring higher attention. These findings underscore the nuanced role of persuasive strategies in modulating attentional resources and cognitive processing. The study offers insights into designing more effective communication messages and highlights the potential for tailored persuasion approaches to influence audience engagement and information processing, with implications for public health campaigns and beyond.

The effect of common parameters of bipolar stimulation on brain evoked potentials

ObjectiveTo identify optimal bipolar stimulation parameters for robust generation of brain evoked potentials (BEPs), namely the interelectrode distance (IED) and the intensity of stimulation (IS), in cortical and axonal stimulation. MethodsIn 15 patients who underwent awake surgery for brain tumor removal, BEPs were elicited at different values of IED and IS, respectively: 5 mm-5 mA, 5 mm-10 mA, and 10 mm-10 mA. The number of BEPs elicited by stimulation, as well as the delays and amplitudes of the N1 waves were compared between the different groups of stimulation parameters and according to the stimulated brain structure (cortical vs. axonal). ResultsThe amplitudes of N1 increased with the intensity of bipolar stimulation, either in cortical or axonal stimulation, while N1 peak delays were not affected by the stimulation parameters. Furthermore, axonal stimulation produced more N1s than cortical stimulation, with lower latencies. ConclusionsUnderstanding the relationship between stimulation parameters and BEP is of utmost importance to determine whether the generated N1 waves accurately reflect the underlying structural anatomy. Other factors, such as stimulation frequency or pulse width and shape, may also play a role and warrant further investigation. SignificanceThis study represents the first step in describing the influence of common bipolar stimulation parameters on robustness of BEPs by examining the impact of IED and IS on the N1 wave.

Responses to brief perturbations of stance: EMG, midline cortical, and subcortical changes.

We studied simultaneous EMG and midline EEG responses, including over the cerebellum, in 10 standing subjects (35 ± 15 yr; 5 females, 5 males). Recordings were made following repeated taps to the sternum, stimuli known to evoke short-latency EMG responses in leg muscles, consistent with postural reflexes. EEG power had relatively more high-frequency components (>30 Hz) when recorded from electrodes over the cerebellum (Iz and SIz) compared with other midline electrodes. We confirmed a previous report using a similar stimulus that evoked short-latency potentials over the cerebellum. We showed clear midline-evoked EEG potentials occurring at short latency over the cerebellum (P23, N31, N42, and P54) and frontally (N28 and N57) before the previously described perturbation-evoked potential (P1/N1/P2). The P23 response correlated with the subsequent EMG response in the tibialis anterior muscles (r = 0.72, P = 0.018), confirming and extending previous observations. We did not find a correlation with the N1 amplitude. We conclude that early activity occurs from electrodes over the inion in response to a brief tap to the sternum. This is likely to represent cerebellar activity and it appears to modulate short-latency postural EMG responses.NEW & NOTEWORTHY We studied the effects of a brief tap to the sternum in human subjects, known to evoke short-latency postural responses. Using an extended EEG recording system, we showed early evoked responses over the midline cerebellum, including the P23 potential, which correlated with the EMG responses in tibialis anterior, consistent with a cerebellar role in postural reflexes. The stimulus also evoked later EEG responses, including the perturbation potential.

Neurophysiological effects of cognitive behavioral therapy in social anxiety: An ERP study using a dot-probe task

BackgroundSocial anxious individuals show attention bias towards emotional stimuli, this phenomenon is considered to be an important cause of anxiety generation and maintenance. Cognitive-behavioral therapy (CBT) is a standard psychotherapy for social anxiety disorder. CBT decreases attention biases by correcting the maladaptive beliefs of socially anxious individuals, but it is not clear whether CBT alters neurophysiological features of socially anxious individuals at early automatic and/or late cognitive strategy stage of attentional processing. MethodTo address this knowledge gap, we collected pre-treatment event-related potential data of 22 socially anxious individuals while they performed a dot-probe task. These participants then received eight weeks of CBT, and post-treatment ERP data were collected after completion of CBT treatment. We also included 29 healthy controls and compared them with individuals with social anxiety to determine the neural mechanisms underlying the effectiveness of CBT. ResultsParticipants’ social anxiety level was significantly alleviated with CBT. ERP results revealed that (1) compared to pre-treatment phase, P1 amplitudes induced by probes significantly decreased at post-treatment phase, whereas P3 amplitudes increased at post-treatment phase; the P1 amplitudes induced by probes following happy-neutral face pairs in socially anxious individuals after treatment was significantly different with that in healthy controls; (2) amplitude of components elicited by face pairs did not change significantly between pre-treatment and post-treatment phases; (3) changes of Liebowitz Social Anxiety Scale were positively correlated with changes of P1 amplitude, and negatively correlated with changes of N1 amplitude. LimitationsOur sample was university students and lacked randomization, which limits the generalizability of the results. ConclusionThe present results demonstrated that CBT may adjust cognitive strategies in the later stage of attentional processing, indicating by changed ERPs appeared in probe-presenting stage for social anxiety.

Music training is associated with better audio-visual integration in Chinese language

In the present study, we aimed to investigate whether long-term music training could improve audio-visual speech integration in Chinese, using event-related brain potential (ERP) measurements. Specifically, we recruited musicians and non-musicians to participate in our experiment where visual Chinese characters were presented simultaneously with congruent or incongruent speech sounds. In order to maintain participants' focus on both auditory and visual modalities, they were instructed to perform a probe detection task. Our study revealed that for the musicians, audiovisual incongruent stimuli elicited larger N1 and N400 amplitudes compared to audiovisual congruent stimuli. Conversely, for the non-musicians, only a larger N400 amplitude was observed for incongruent stimuli relative to congruent stimuli, without a significant difference in N1 amplitude. Furthermore, correlation analyses indicated that more years of music training was associated with a larger N1 effect for the musicians. These results suggest that musicians were capable of detecting character-speech sound incongruence at an earlier time window compared to non-musicians. Overall, our findings provide compelling evidence that music training is associated with better integration of visual characters and auditory speech sounds in language processing.

Overt and Covert Effects of Mental Fatigue on Attention Networks: Evidence from Event-Related Potentials during the Attention Network Test.

Mental fatigue is a variation in the psychophysiological state that subjects encounter during or after prolonged cognitive activity periods, affecting top-down attention and cognitive control. The present study aimed to investigate the effects of mental fatigue on attention in the context of the three attention networks according to the Posnerian model (alerting, orienting, and executive networks) by combining the Attentional Network Test (ANT) and event-related potentials technique. Thirty healthy subjects were enrolled in the study. A continuous arithmetic task lasting one hour induced mental fatigue, and EEG recordings were conducted before and after the task while subjects were performing the ANT. The efficiencies of three networks were comparable between groups, while RTs shortened only in the control group and the accuracy related to the alerting and conflict networks declined only after mental effort. Mental fatigue reduced N1 amplitude during alerting network engagement and p3 amplitude during orienting. It also reduced N2 and P3 amplitude during the conflict, particularly the incongruent target-locked response. These findings underscore the covert effects of mental fatigue on attention, suggesting that even in healthy young subjects, compensatory mechanisms may maintain adequate overt performances, but fatigue still has a detrimental effect on top-down attentional mechanisms.

Developmental trajectory and sex differences in auditory processing in a PTEN-deletion model of autism spectrum disorders

Autism Spectrum Disorders (ASD) encompass a wide array of debilitating symptoms, including severe sensory deficits and abnormal language development. Sensory deficits early in development may lead to broader symptomatology in adolescents and adults. The mechanistic links between ASD risk genes, sensory processing and language impairment are unclear. There is also a sex bias in ASD diagnosis and symptomatology. The current study aims to identify the developmental trajectory and genotype- and sex-dependent differences in auditory sensitivity and temporal processing in a Pten-deletion (phosphatase and tensin homolog missing on chromosome 10) mouse model of ASD. Auditory temporal processing is crucial for speech recognition and language development and deficits will cause language impairments. However, very little is known about the development of temporal processing in ASD animal models, and if there are sex differences. To address this major gap, we recorded epidural electroencephalography (EEG) signals from the frontal (FC) and auditory (AC) cortex in developing and adult Nse-cre PTEN mice, in which Pten is deleted in specific cortical layers (layers III-V) (PTEN conditional knock-out (cKO). We quantified resting EEG spectral power distribution, auditory event related potentials (ERP) and temporal processing from awake and freely moving male and female mice. Temporal processing is measured using a gap-in-noise-ASSR (auditory steady state response) stimulus paradigm. The experimental manipulation of gap duration and modulation depth allows us to measure cortical entrainment to rapid gaps in sounds. Temporal processing was quantified using inter-trial phase clustering (ITPC) values that account for phase consistency across trials. The results show genotype differences in resting power distribution in PTEN cKO mice throughout development. Male and female cKO mice have significantly increased beta power but decreased high frequency oscillations in the AC and FC. Both male and female PTEN cKO mice show diminished ITPC in their gap-ASSR responses in the AC and FC compared to control mice. Overall, deficits become more prominent in adult (p60) mice, with cKO mice having significantly increased sound evoked power and decreased ITPC compared to controls. While both male and female cKO mice demonstrated severe temporal processing deficits across development, female cKO mice showed increased hypersensitivity compared to males, reflected as increased N1 and P2 amplitudes. These data identify a number of novel sensory processing deficits in a PTEN-ASD mouse model that are present from an early age. Abnormal temporal processing and hypersensitive responses may contribute to abnormal development of language function in ASD.

Mismatch negativity between discriminating and undiscriminating participants on the front-back sound localization

Sound localization in the front-back dimension is reported to be challenging, with individual differences. We investigated whether auditory discrimination processing in the brain differs based on front-back sound localization ability. This study conducted an auditory oddball task using speakers in front of and behind the participants. We used event-related brain potentials to examine the deviance detection process between groups that could and could not discriminate front-back sound localization. The results indicated that mismatch negativity (MMN) occurred during the deviance detection process, and P2 amplitude differed between standard and deviant locations in both groups. However, the latency of MMN was shorter in the group that could discriminate front-back sounds than in the group that could not. Additionally, N1 amplitude increased for deviant locations compared to standard ones only in the discriminating group. In conclusion, the sensory memories matching process based on traces of previously presented stimuli (MMN, P2) occurred regardless of discrimination ability. However, the response to changes in the physical properties of sounds (MMN latency, N1 amplitude) differed depending on the ability to discriminate front-back sounds. Our findings suggest that the brain may have different processing strategies for the two directions even without subjective recognition of the front-back direction of incoming sounds.

The temporal mismatch across listening sides affects cortical auditory evoked responses in normal hearing listeners and cochlear implant users with contralateral acoustic hearing

Combining a cochlear implant with contralateral acoustic hearing typically enhances speech understanding, although this improvement varies among CI users and can lead to an interference effect. This variability may be associated with the effectiveness of the integration between electric and acoustic stimulation, which might be affected by the temporal mismatch between the two listening sides. Finding methods to compensate for the temporal mismatch might contribute to the optimal adjustment of bimodal devices and to improve hearing in CI users with contralateral acoustic hearing.The current study investigates cortical auditory evoked potentials (CAEPs) in normal hearing listeners (NH) and CI users with contralateral acoustic hearing. In NH, the amplitude of the N1 peak and the maximum phase locking value (PLV) were analyzed under monaural, binaural, and binaural temporally mismatched conditions. In CI users, CAEPs were measured when listening with CI only (CIS_only), acoustically only (AS_only) and with both sides together (CIS+AS). When listening with CIS+AS, various interaural delays were introduced between the electric and acoustic stimuli.In NH listeners, interaural temporal mismatch resulted in decreased N1 amplitude and PLV. Moreover, PLV is suggested as a more sensitive measure to investigate the integration of information between the two listening sides.CI users showed varied N1 latencies between the AS_only and CIS_only listening conditions, with increased N1 amplitude when the temporal mismatch was compensated. A tendency towards increased PLV was also observed, however, to a lesser extent than in NH listeners, suggesting a limited integration between electric and acoustic stimulation.This work highlights the potential of CAEPs measurement to investigate cortical processing of the information between two listening sides in NH and bimodal CI users.

N1 and LNC reveal the differential electrophysiological signatures of functional and hedonic images processing

In the process of creative sentence or phrase utilization, novel and appropriate evaluations cause the different brain responses observed in event-related potentials: the N400 reflects the novelty evaluation, whereas a late negative component marks appropriate processing. Do we have similar brain reactions in image perception when we rapidly browse pictures of objects with different novelty, functional/appropriate, and hedonic value? To explore this question, participants were presented with four novel object images with high or low functional and hedonic properties, as well as the ordinary product images, with the instruction to attentively observe and understand each image. We found a clear dissociation between processing of novelty and functional value: novelty objects produced negative deflections in the N2–N400 time window relative to the ordinary object images, whereas images with high functional value elicited a larger N2 and late negative waves (LNC) resembling the late component found for the appropriate phrases. Object images with high hedonic value, however, were associated with earlier aesthetic preference reflected in smaller N1 amplitudes, but failed to elicit a LNC effect. We therefore conclude that the processing of novelty, functional, and hedonic value are dissociation, and the perception of hedonic value is earlier (N1) than the novelty processing (N400) and the verification of functional value (LNC).

Effect of interactive scalp acupuncture on upper limb function in patients with hemiplegia after stroke

To explore the clinical effect of interactive scalp acupuncture combined with task-oriented mirror therapy on hemiplegia after stroke. A total of 86 patients with hemiplegia after stroke were randomly divided into an observation group (43 cases, 2 cases dropped out) and a control group (43 cases, 2 cases dropped out). Both groups received routine treatment and rehabilitation treatment for stroke. The control group was treated with task-oriented mirror therapy, 40 min each time, once a day, 6 days a week. The observation group was treated with interactive scalp acupuncture at ipsilateral upper 1/5 and 2/5 of the parietal and temporal anterior oblique line and upper 1/5 and 2/5 of the parietal and temporal posterior oblique line on the basis of the treatment as the control group, 45 min each time, once a day, 6 days a week. Both groups were treated for 4 weeks. Before and after treatment and in follow-up of 8 weeks after treatment completion, the Fugl-Meyer assessment (FMA) score, modified Ashworth scale (MAS) score, shoulder abduction angle, wrist dorsiflexion angle and N20 latency and amplitude of somatosensory evoked potential were compared between the two groups. After treatment and in follow-up, the FMA scores were increased (P<0.01), the MAS scores were decreased (P<0.01) compared with those before treatment in the two groups; the FMA scores in the observation group were higher than those in the control group (P<0.01), the MAS scores were lower than those in the control group (P<0.01). After treatment and in follow-up, the shoulder abduction angle and wrist dorsiflexion angle was increased (P<0.01), the N20 latency was shortened and amplitude was increased (P<0.01) compared with that before treatment in both groups; the shoulder abduction angle and wrist dorsiflexion angle in the observation group was greater than that in the control group (P<0.01), the N20 latency was shorter than that in the control group (P<0.01), and the N20 amplitude was higher than that in the control group (P<0.01). Interactive scalp acupuncture combined with task-oriented mirror therapy can improve upper limb function in patients with hemiplegia after stroke, and reduce the muscular tone of the affected limb.

Intact painful sensation but enhanced non-painful sensation in individuals with autistic traits.

Somatosensory abnormalities are commonly recognized as diagnostic criteria in autism spectrum disorder (ASD), and may also exist in individuals with autistic traits. The present research included two studies to explore the painful and non-painful sensation and their cognitive-neurological mechanisms of individuals with autistic traits. Study 1 included 358 participants to assess the relationship between autistic traits and pain/non-pain sensitivities using questionnaires: the Autism Spectrum Quotient (AQ), the Pain Sensitivity Questionnaire, and the Highly Sensitive Person Scale, respectively. Study 1 found that autistic traits were positively correlated with non-pain sensitivity, but not associated with pain sensitivity. Study 2 recruited 1,167 participants whose autistic traits were assessed using the AQ. Subsequently, thirty-three participants who scored within the top 10% and bottom 10% on the AQ were selected into High-AQ and Low-AQ groups, respectively, to explore the cognitive-neural responses of individuals with autistic traits to both painful and non-painful stimuli with event-related potential (ERP) technology. Results of Study 2 showed that the High-AQ group showed higher intensity ratings, more negative emotional reactions, and larger N1 amplitudes than the Low-AQ group to the non-painful stimuli, but no difference of response to the painful stimuli was found between High-AQ and Low-AQ groups. These findings suggest that individuals with autistic traits may experience enhanced non-painful sensation but intact painful sensation.

The paradox of social avoidance and the yearning for understanding: Elevated interbrain synchrony among socially avoidant individuals during expression of negative emotions

Social avoidance refers to the tendency to be alone and non-participating to social interactions, which is considered to hamper health interpersonal relationship. However, the neural underpinnings of social and emotional interactions among social avoidant individuals have not been fully studied. In the present study, we used EEG hyperscanning technology to investigate the brain activity and its synchronization of 25 socially avoidant dyads and 28 comparison dyads during an emotional communication task. The emotional communication task consisted of the emotional processing stage and emotional interaction stage. Event-related potentials (ERPs) of the senders during the emotional processing stage and the interbrain synchrony (IBS) of the dyads during the emotional interaction stage were analyzed. Results showed that (1) socially avoidant group showed higher beta, theta and gamma IBS in the negative condition than in the positive and neutral condition; (2) in positive condition, the N1 and LPP amplitudes during the emotional processing stage of socially avoidant individuals were negatively correlated with the IBS within dyads during the emotional communication stage. The findings suggest that the dysfunctional emotional interaction of social avoidant individuals may be attributed to the negative impact of emotional stimuli processing during emotional communication.

A meta-analysis comparing the performance of narrowband CE-Chirp and 500 Hz tone burst stimuli in recording cervical vestibular evoked myogenic potential (cVEMP)

Due to contradictory outcomes in the literature, the aim of this meta-analysis is to verify whether the narrowband (NB) CE-Chirp stimulus (centred at 500 Hz) would produce more robust cervical vestibular evoked myogenic potential (cVEMP) responses relative to the conventional 500 Hz tone burst. The literature search was conducted using PubMed, Scopus, and Web of Science databases and the terms used were “vestibular evoked myogenic potential” and “chirp”. The cVEMP parameters to be analysed were P1 latency, N1 latency, and P1–N1 amplitude. A total of 59 potential articles were obtained from the database search. Eventually, five articles were found to be eligible for the meta-analysis (with n = 222). As found, P1 and N1 latencies of cVEMP were significantly shorter for the chirp stimulus (p < 0.001), with substantially large effect sizes. On the other hand, P1–N1 amplitude values were found to be not statistically different between the two stimuli (p = 0.189), with a small effect size. It appears that there is no indication to support the superiority of the NB CE-Chirp stimulus (centred at 500 Hz) in the cVEMP testing (relative to the conventional 500 Hz tone burst). In particular, both stimuli produce comparable P1–N1 amplitude values. Even though P1 and N1 latencies are statistically shorter for the chirp stimulus, this may not reflect that it should be the preferred stimulus for recording cVEMP responses (and the reasons for this are discussed accordingly).