Social-Specific Impairment of Negative Emotion Perception in Alexithymia

The mediating effect of internet addiction and the moderating effect of physical activity on the relationship between alexithymia and depression

There is a certain relationship between alexithymia and depression, but further investigation is needed to explore their underlying mechanisms. The aims of this study was to explore the mediating role of internet addiction between alexithymia and depression and the moderating role of physical activity. A total of 594 valid responses were included in the analysis, with a mean age of 18.72 years (SD = 1.09). The sample comprised 250 males (42.09%) and 344 females (57.91%). These responses were utilized for descriptive analysis, correlation analysis, regression analysis, and the development of mediation and moderation models. Alexithymia showed positive correlations with depression and internet addiction, and physical activity was negatively correlated with internet addiction and depression. Internet addiction partially mediated the relationship between alexithymia and depression, while physical activity weakened the association between internet addiction and depression, acting as a moderator. Our findings suggest that excessive Internet engagement may mediate the relationship between alexithymia and depression as an emotional regulatory coping strategy, and that physical activity attenuates the predictive effect of Internet addiction on depression.

Alexithymia modulates emotion concept activation during facial expression processing

Alexithymia is characterized by difficulties in emotional information processing. However, the underlying reasons for emotional processing deficits in alexithymia are not fully understood. The present study aimed to investigate the mechanism underlying emotional deficits in alexithymia. Using the Toronto Alexithymia Scale-20, we recruited college students with high alexithymia (n = 24) or low alexithymia (n = 24) in this study. Participants judged the emotional consistency of facial expressions and contextual sentences while recording their event-related potentials. Behaviorally, the high alexithymia group showed longer response times versus the low alexithymia group in processing facial expressions. The event-related potential results showed that the high alexithymia group had more negative-going N400 amplitudes compared with the low alexithymia group in the incongruent condition. More negative N400 amplitudes are also associated with slower responses to facial expressions. Furthermore, machine learning analyses based on N400 amplitudes could distinguish the high alexithymia group from the low alexithymia group in the incongruent condition. Overall, these findings suggest worse facial emotion perception for the high alexithymia group, potentially due to difficulty in spontaneously activating emotion concepts. Our findings have important implications for the affective science and clinical intervention of alexithymia-related affective disorders.

Caregiver-child interaction as an effective tool for identifying autism spectrum disorder: evidence from EEG analysis

BACKGROUND

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder that affects individuals across their lifespan. Early diagnosis and intervention are crucial for improving outcomes. However, current diagnostic methods are often time-consuming, and costly, making them inaccessible to many families. In the current study, we aim to test caregiver-child interaction as a potential tool for screening children with ASD in clinic.

METHODS

We enrolled 85 preschool children (Mean age: 4.90 ± 0.65 years, 70.6% male), including ASD children with or without developmental delay (DD), and typical development (TD) children, along with their caregivers. ASD core symptoms were evaluated by Childhood Autism Rating Scale (CARS) and Autism Diagnostic Observation Schedule-Calibrated Severity Scores (ADOS-CSS). Behavioral indicators were derived from video encoding of caregiver-child interaction, including social involvement of children (SIC), interaction time (IT), response of children to social cues (RSC), time for caregiver initiated social interactions (GIS) and time for children initiated social interactions (CIS)). Power spectral density (PSD) values were calculated by EEG signals simultaneously recorded. Partial Pearson correlation analysis was used in both ASD groups to investigate the correlation among behavioral indicators scores and ASD symptom severity and PSD values. Receiver operating characteristic (ROC) analysis was used to describe the discrimination accuracy of behavioral indicators.

RESULTS

Compared to TD group, both ASD groups demonstrated significant lower scores of SIC, IT, RSC, CIS (all p values < 0.05), and significant higher time for GIS (all p values < 0.01). SIC scores negatively correlated with CARS (p = 0.006) and ADOS-CSS (p = 0.023) in the ASD with DD group. Compared to TD group, PSD values elevated in ASD groups (all p values < 0.05), and was associated with SIC (theta band: p = 0.005; alpha band: p = 0.003) but not IQ levels. SIC was effective in identifying both ASD groups (sensitivity/specificity: ASD children with DD, 76.5%/66.7%; ASD children without DD, 82.6%/82.2%).

CONCLUSION

Our results verified the behavioral paradigm of caregiver-child interaction as an efficient tool for early ASD screening.

Recognition of Emotional and Neutral Visual Scenes in Carriers of the MAOA, COMT, DRD4, and 5HT2A Gene Polymorphisms

Background

It is known that some genes regulate neurochemical metabolism, and their polymorphisms affect cognitive performance, including the ability to categorize emotionally significant information.

Objective

The aim of our study was to analyze the recognition of emotional and neutral visual scenes in carriers of different polymorphic variants of the MAOA, COMT, DRD4, and 5HT2A genes.

Design

The study sample consisted of 87 university students (Caucasians, women 63%, average age 20.4±2.6 years). The genotypes of the COMT, 5HT2A, and DRD4 genes were determined by polymerase chain reaction. Agarose gel electrophoresis was used to determine the number of tandem repeats of the MAOA gene. Three hundred sixty (360) photographic images of scenes of different emotional valence (positive, negative, and neutral - 120 images for each category) were used as stimuli. These images were classified by expert assessments. The images were presented in a random sequence. The exposure time was 700 ms. The research participants were asked to determine the emotional valence of each scene.

Results

We found that only the COMT gene genotype affected the recognition of emotional and neutral visual scenes. Carriers of the COMT Val/Val genotype, which causes dopamine to stay in the synaptic space for a shorter time, are better in recognizing and demonstrate higher sensitivity to the emotional content of scenes. Carriers of the Val/Met genotype demonstrated the worst ability to differentiate the emotional valence of visual scenes.

Conclusion

This study has shown that the length of stay of monoamines in the synaptic space regulated by the COMT gene affects the recognition of emotional visual information.

OXTR polymorphisms and parental bonding modulate alexithymia: The main effects and interaction

Alexithymia is a subclinical personality disorder characterized by difficulties in identifying and expressing one's own emotion. Individual differences in alexithymia are influenced by both genetic and environmental factors. However, the interplay between these factors and their influences on alexithymia are unclear. Considering that oxytocin plays important roles in emotion processing and that parental bonding influences the development of alexithymia, we explored the associations between OXTR polymorphisms and alexithymia and examined whether the potential associations are moderated by parental bonding. To this end, we genotyped the OXTR polymorphisms (rs53576 and rs1042778) and scored alexithymia and parental bonding with the Toronto Alexithymia Scale and the Parental Bonding Instrument. Results indicated that: (1) the characteristics of alexithymia were negatively associated with parental care and positively with parental overprotection; (2) the OXTR rs53576 was significantly associated with the characteristics of alexithymia, such that the AA genotype was associated with fewer difficulties in identifying feelings and describing feelings than the AG/GG genotypes; and (3) the OXTR rs1042778 interacted with parental care in alexithymia with the vantage sensitivity model: the GG genotype was related to less severity of alexithymia than the AG/GG genotypes only in individuals with higher parental care. Overall, these findings suggest that the OXTR is related to alexithymia and that the quality of parental care influences the relationship. However, considering that the evidence from this study is weak, more research is needed to understand the roles of OXTR in alexithymia.

High-definition transcranial direct current stimulation modulates eye gaze on emotional faces in college students with alexithymia: An eye-tracking study

BACKGROUND

Atypical eye gaze on emotional faces is a core feature of alexithymia. The inferior frontal gyrus (IFG) is considered to be the neurophysiological basis of alexithymia-related emotional face fixation. Our aim was to examine whether anodal high-definition transcranial direct current stimulation (HD-tDCS) administered to the right (r)IFG would facilitate eye gaze of emotional faces in alexithymia individuals.

METHOD

Forty individuals with alexithymia were equally assigned to anodal or sham HD-tDCS of the rIFG according to the principle of randomization. The individuals then completed a free-viewing eye tracking task (including happy, sad, and neutral faces) before and after 5 consecutive days of stimulation (twice a day).

RESULTS

The results showed that twice a day anodal HD-tDCS of the rIFG significantly increased the fixation time and fixation count of the eye area on happy and neutral faces, but there was no significant effect on sad faces. According to the temporal-course analysis, after the intervention, the fixation time on neutral faces increased significantly at almost all time points of the eye tracking task. For happy faces, the improvement was demonstrated between 500 and 1000 ms and between 2500 and 3500 ms. For sad faces, the fixation time improved but not significantly.

CONCLUSIONS

Applying high-dose anodal HD-tDCS to the rIFG selectively facilitated eye gaze in the eye area of neutral and happy faces in individuals with alexithymia, which may improve their face processing patterns.

Perceptive and Affective Impairments In Emotive Eye-Region Processing in Alexithymia

Alexithymia is characterized by impairments in emotion processing, frequently linked to facial expressions of emotion. The eye-region conveys information necessary for emotion processing. It has been demonstrated that alexithymia is associated with reduced attention to the eyes, but little is known regarding the cognitive and electrophysiological mechanisms underlying emotive eye-region processing in alexithymia. Here, we recorded behavioral and electrophysiological responses of individuals with alexithymia (ALEX; n = 25) and individuals without alexithymia (NonALEX; n = 23) while they viewed intact and eyeless faces with angry and sad expressions during a dual-target rapid serial visual presentation task. Results showed different eye-region focuses and differentiating N1 responses between intact and eyeless faces to anger and sadness in NonALEX, but not in ALEX, suggesting deficient perceptual processing of the eye-region in alexithymia. Reduced eye-region focus and smaller differences in frontal alpha asymmetry in response to sadness between intact and eyeless faces were observed in ALEX than NonALEX, indicative of impaired affective processing of the eye-region in alexithymia. These findings highlight perceptual and affective abnormalities of emotive eye-region processing in alexithymia. Our results contribute to understanding the neuropsychopathology of alexithymia and alexithymia-related disorders.

Hormonal abnormalities in alexithymia

Alexithymia is a personality trait characterized by difficulties in emotion recognition and regulation that is associated with deficits in social cognition. High alexithymia levels are considered a transdiagnostic risk factor for a range of psychiatric and medical conditions, including depression, anxiety, and autism. Hormones are known to affect social-emotional cognition and behavior in humans, including the neuropeptides oxytocin and vasopressin, the steroid hormones testosterone and estradiol, the stress hormone cortisol as well as thyroid hormones. However, few studies have investigated hormonal effects on alexithymia and on alexithymia-related impairments in emotion regulation and reactivity, stress response, and social cognition. Here, we provide a brief overview of the evidence linking alexithymia to abnormalities in hormone levels, particularly with regard to cortisol and oxytocin, for which most evidence exists, and to thyroid hormones. We address the current lack of research on the influence of sex hormones on alexithymia and alexithymia-related deficits, and lastly provide future directions for research on associations between hormonal abnormalities and deficits in emotion regulation and social cognition associated with alexithymia.