Altered neuronal habituation to hearing others' pain in adults with autistic traits

Group empathy for pain is stronger than individual empathy for pain in the auditory modality

Humans live in collective groups and are highly sensitive to perceived emotions of a group, including the pain of a group. However, previous research on empathy for pain mainly focused on the suffering of a single individual ("individual empathy for pain"), with limited understanding of empathy for pain to a group ("group empathy for pain"). Thus, the present study aimed to investigate the cognitive neural mechanisms of group empathy for pain in the auditory modality. The study produced group painful voices to simulate the painful voices made by a group, and recruited 34 participants to explore differences between their responses to group painful voices and individual painful voices using the event-related potential (ERP) techniques. The results revealed that group painful voices were rated with higher pain intensity, more negative affective valence, and larger P2 amplitudes than individual painful voices. Furthermore, trait affective empathy scores of the participants were positively correlated with their P2 amplitudes of group painful voices. The results suggested that the group empathy for pain may facilitate affective empathetic processing in auditory modality.

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 relationship between autistic traits and the stress of social isolation: Development of an explanatory model

Background

Social isolation can be particularly challenging for individuals with high autistic traits who struggle with social interactions. The COVID-19 pandemic led to increased isolation, exacerbating stress for those who may have difficulty in connecting with others. This study aimed to explore the relationship between autistic traits and stress associated with social isolation.

Methods

A sample of 1597 Chinese adults completed measures of autistic traits, the stress of social isolation, psychological inflexibility and core self-evaluation, during an epidemic prevention and control period of COVID-19 in Chongqing, China. Measures included the Autism-Spectrum Quotient, Coronavirus Stress Measure, Acceptance and Action Questionnaire-II, and Core Self-Evaluation Scale.

Results

Autistic traits were positively correlated with the stress of social isolation, which was mediated by the chain effect of core self-evaluation and psychological inflexibility. individuals with high autistic traits reported significantly higher stress than individuals with low autistic traits.

Limitations

This was a cross-sectional study, which limits causal inference. In addition, data were self-reported, which may cause methodological effects. Finally, this study was conducted during China's quarantine policy and external validation of the findings is required.

Conclusions

Autistic traits are positively associated with the stress of social isolation. Autistic traits affected core self-evaluation first, and psychological inflexibility subsequently, leading to the stress of social isolation. individuals with high autistic traits tended to experience higher levels of stress during pandemic quarantines. The findings provide useful evidence for developing interventions and implementing preventive measures to reduce stress in individuals with high autistic traits and autism spectrum disorder.

The Empathy for Pain Stimuli System (EPSS): Development and preliminary validation

We present the Empathy for Pain Stimuli System (EPSS): a large-scale database of stimuli for studying people's empathy for pain. The EPSS comprises five sub-databases. First, the Empathy for Limb Pain Picture Database (EPSS-Limb) provides 68 painful and 68 non-painful limb pictures, exhibiting people's limbs in painful and non-painful situations, respectively. Second, the Empathy for Face Pain Picture Database (EPSS-Face) provides 80 painful and 80 non-painful pictures of people's faces being penetrated by a syringe or touched by a Q-tip. Third, the Empathy for Voice Pain Database (EPSS-Voice) provides 30 painful and 30 non-painful voices exhibiting either short vocal cries of pain or neutral interjections. Fourth, the Empathy for Action Pain Video Database (EPSS-Action_Video) provides 239 painful and 239 non-painful videos of whole-body actions. Finally, the Empathy for Action Pain Picture Database (EPSS-Action_Picture) provides 239 painful and 239 non-painful pictures of whole-body actions. To validate the stimuli in the EPSS, participants evaluated the stimuli using four different scales, rating pain intensity, affective valence, arousal, and dominance. The EPSS is available to download for free at https://osf.io/muyah/?view_only=33ecf6c574cc4e2bbbaee775b299c6c1 .

Autistic traits and event-related potentials in the general population: A scoping review and meta-analysis

BACKGROUND

Differences in short and long-latency Event-Related Potentials (ERPs) can help us infer abnormalities in brain processing, considering early and later stages of stimuli processing across tasks and conditions. In autism research, the adult population remains largely understudied compared to samples at early stages of development. In this context, this scoping review briefly summarises what has been described in community and subclinical adult samples of autism.

METHOD

The current scoping review and meta-analysis includes 50 records (N = 1652) and comprehensively explores short and long-latency ERP amplitudes and their relationship with autistic traits in adult community samples.

RESULTS

This meta-analysis identified, with small to medium effect sizes, distinctive patterns in late ERP amplitudes, indicating enhanced responses to visual stimuli and the opposite patterns to auditory tasks in the included sample. Additionally, a pattern of higher amplitudes was also found for the component P3b in autistic traits.

DISCUSSION

Differential effects in visual and auditory domains are explored in light of the predictive processing framework for Autism. It remains possible that different brain mechanisms operate to explain symptoms related with different sensory modalities. P3b is discussed as a possible component of interest in future studies as it revealed a more robust effect for differentiating severity in the expression of autistic traits in adulthood.

The effect of top-down attention on empathy fatigue

Prolonged exposure to others' suffering can lead to empathy fatigue, especially when individuals struggle to effectively regulate their empathic capacity. Shifting active attention away from emotional components toward cognitive components of others' suffering is an effective strategy for mitigating empathy fatigue. This research investigated how top-down attentional manipulation modulates empathy fatigue in both auditory (Study 1) and visual (Study 2) modalities. Participants completed two tasks in both studies: (i) the attention to cognitive empathy task (A-C task) and (ii) the attention to emotional empathy task (A-E task). Each task included three blocks (Time Block 1, Time Block 2, and Time Block 3) designed to induce empathy fatigue. Study 1 revealed that the A-C task reduced empathy fatigue and N1 amplitudes than the A-E task in Time Block 3, indicating that attention to cognitive empathy might decrease auditory empathy fatigue. Study 2 indicates that the A-C task caused a longer N2 latency than the A-E task, signifying a decelerated emotional empathic response when attention was on cognitive empathy in the visual modality. Overall, prioritizing cognitive empathy seems to conserve mental resources and reduce empathy fatigue. This research documented the relationship between top-down attention and empathy fatigue and the possible neural mechanism.

Capsaicin-induced pain increases neural responses to low-calorie non-spicy food cues: An ERP study

Capsaicin, the main spicy ingredient in chili, can activate pain receptors on the human tongue and skin. Although some studies have determined that pain influenced preference for high-calorie foods, little is known whether pain can modulate the individuals' preference for spicy foods and its neural mechanisms. After 30 participants underwent painful (topical capsaicin cream) and control (hand cream) treatments, an event-related potential (ERP) study was conducted to investigate the modulation of capsaicin-induced pain on food preference with food images. Results showed that both P3 and late positive potential (LPP) amplitudes during the painful treatment were significantly larger than those during the control treatment for low-calorie non-spicy food cues. However, for the other three categories of food cues, there were no significant differences between the two treatments. The present study suggests that capsaicin-induced pain increases individuals' neural processing of low-calorie non-spicy food cues, which provides empirical evidence on the relationship between pain and neural responses to food cues to help optimize dietary interventions for patients experiencing pain.

Altered Processing of Social Emotions in Individuals With Autistic Traits

Social impairment is a defining phenotypic feature of autism. The present study investigated whether individuals with autistic traits exhibit altered perceptions of social emotions. Two groups of participants (High-AQ and Low-AQ) were recruited based on their scores on the autism-spectrum quotient (AQ). Their behavioral responses and event-related potentials (ERPs) elicited by social and non-social stimuli with positive, negative, and neutral emotional valence were compared in two experiments. In Experiment 1, participants were instructed to view social-emotional and non-social emotional pictures. In Experiment 2, participants were instructed to listen to social-emotional and non-social emotional audio recordings. More negative emotional reactions and smaller amplitudes of late ERP components (the late positive potential in Experiment 1 and the late negative component in Experiment 2) were found in the High-AQ group than in the Low-AQ group in response to the social-negative stimuli. In addition, amplitudes of these late ERP components in both experiments elicited in response to social-negative stimuli were correlated with the AQ scores of the High-AQ group. These results suggest that individuals with autistic traits have altered emotional processing of social-negative emotions.

Empathy for pain in individuals with autistic traits during observation of static and dynamic stimuli

Previous studies have reported that individuals with autistic traits, like those with Autism Spectrum Disorder (ASD), may have impaired empathic responses when observing static stimuli of others' pain. However, it remains unclear whether individuals with autistic traits exhibit impaired empathy for pain in response to dynamic stimuli. The present study addressed this question by recruiting 529 individuals whose autistic traits were assessed using the autism-spectrum quotient (AQ) questionnaire. Thirty participants who scored within the top 10% and bottom 10% on the AQ were selected into High-AQ and Low-AQ groups, respectively. This study employed painful whole-body action pictures and videos as static and dynamic stimuli. Both groups were instructed to judge whether the models in the stimuli were experiencing pain, and their reaction times, accuracy and event-related potential (ERP) data were recorded. Results showed that the P2 amplitudes were larger in the High-AQ group than in the Low-AQ group when viewing painful static stimuli, while no difference between the two groups was found when viewing painful dynamic stimuli. These results suggest that autistic traits influenced the emotional processing of others' pain in response to static stimuli.

Processing of expressions by individuals with autistic traits: Empathy deficit or sensory hyper-reactivity?

Individuals with autistic traits display impaired social interaction and communication in everyday life, but the underlying cognitive neural mechanisms remain very unclear and still remain controversial. The mind-blindness hypothesis suggests that social difficulties in individuals with autistic traits are caused by empathy impairment in individuals; however, the intense world theory suggests that these social difficulties are caused by sensory hyper-reactivity and sensory overload, rather than empathy impairment. To further test these two theories, this study investigated event-related potentials (ERPs) to explore the cognitive neural processing of repetitive expressions in individuals with autistic traits. This study employed the Mandarin version of the autism-spectrum quotient (AQ) to assess autistic traits in 2,502 healthy adults. Two subset groups were used, e.g., the participants of a high-AQ group were randomly selected among the 10% of individuals with the highest AQ scores; similarly, the participants in the low-AQ group were randomly selected from the 10% of participants with the lowest AQ scores. In an experiment, three different facial expressions (positive, neutral, or negative) of the same person were presented successively and pseudo-randomly in each trial. Participants needed to define the expression of the face that was presented last. The results showed that compared with the low-AQ group, the high-AQ group exhibited higher P1 amplitudes induced by the second and third presented expressions, as well as higher P3 amplitudes induced by the third presented negative expressions. This indicates that individuals with autistic traits may experience overly strong perception, attention, and cognitive evaluation to repetitive expressions, particularly negative expressions. This result supports the intense world theory more strongly than the mind-blindness hypothesis.