Aberrant reward prediction error during Pavlovian appetitive learning in alexithymia

Extensive literature shows that alexithymia, a subclinical trait defined by difficulties in identifying and describing feelings, is characterized by multifaceted impairments in processing emotional stimuli. Nevertheless, its underlying mechanisms remain elusive. Here, we hypothesize that alexithymia may be characterized by an alteration in learning the emotional value of encountered stimuli and test this by assessing differences between individuals with low (LA) and high (HA) levels of alexithymia in the computation of reward prediction errors (RPEs) during Pavlovian appetitive conditioning. As a marker of RPE, the amplitude of the feedback-related negativity (FRN) event-related potential was assessed while participants were presented with two conditioned stimuli (CS) associated with expected or unexpected feedback, indicating delivery of reward or no-reward. No-reward (vs reward) feedback elicited the FRN both in LA and HA. However, unexpected (vs expected) feedback enhanced the FRN in LA but not in HA, indicating impaired computation of RPE in HA. Thus, although HA show preserved sensitivity to rewards, they cannot use this response to update the value of CS that predict them. This impairment may hinder the construction of internal representations of emotional stimuli, leaving individuals with alexithymia unable to effectively recognize, respond and regulate their response to emotional stimuli.

The influence of alexithymia on memory for emotional faces and realistic social interactions

High levels of alexithymia are typically associated with impaired memory for emotional, but not neutral words. We conducted two experimental studies to establish if this effect generalises to non-verbal socially relevant stimuli. Thirty-nine female undergraduates (Study 1) viewed faces with different expressions (neutral, angry, happy or sad) and 38 female students (Study 2) viewed videos of realistic social interactions (featuring anger, happiness, sadness or neutral affect). Participants were asked to identify the emotion portrayed and were subsequently given an intentional recognition memory test for the stimuli. They also completed self-report measures of alexithymia and mood (depression & anxiety). In Study 1, memory for emotional (especially angry), but not neutral faces was negatively related to the "difficulty describing feelings" facet of alexithymia. In Study 2, memory for emotional (particularly those featuring anger), but not neutral videos was negatively related to the "difficulty identifying feelings" and "externally oriented thinking" facets of alexithymia. In both studies, these memory deficits were independent of the effects of age and mood. Furthermore, the deficits appear to be most evident in the conscious recollection of the emotional stimuli. Our findings confirm that the memory deficit for emotional words in alexithymia generalises to important non-verbal socially relevant stimuli.

Alexithymia and the Reduced Ability to Represent the Value of Aversively Motivated Actions

Alexithymia is a subclinical trait defined by difficulties in identifying and describing feelings and a cognitive style avoidant of introspection. Extensive literature shows that alexithymia is characterized by multifaceted impairments in processing emotional stimuli. Nevertheless, the mechanisms that may account for such impairments remain elusive. Here, we hypothesize that alexithymia may be understood as impairment in learning the emotional value of one’s own actions and test this comparing performance of participants with high (HA) and low (LA) levels of alexithymia on a probabilistic selection task. Results show that, compared to LA, HA need more time to learn the value of individual stimuli and associated actions as difference in reinforcement rate between stimuli decreases. In addition, HA appear less able to generalize the value of previously learned actions that lead to a negative outcome, to make adaptive choices in a new context, requiring more time to avoid the most negative stimulus between two negative stimuli. Together, the results indicate that individuals with alexithymia show impaired learning of the value of aversively motivated actions. We argue that this impairment may hinder the construction of internal representations of emotional stimuli and actions and represent a mechanism that may account for the difficulties of alexithymia in processing emotional stimuli.

Autonomic Reactivity to Arousing Stimuli with Social and Non-social Relevance in Alexithymia

Emotional difficulties in alexithymia and their social consequences have been linked to alterations in autonomic nervous system. However, most of previous studies did not take into account the distinction between the affective and the cognitive dimensions of the alexithymia, leading to inconsistent results. Aim: In this study, we compared the effects of both dimensions of alexithymia on the autonomic arousal to emotional and social visual stimulations. Methods: Skin conductance responses (SCRs) to items of the International Affective Pictures System characterized by emotional (unpleasant, neutral, and pleasant), social (with humans) or non-social (without humans) content were recorded in non-alexithymic (NA), affective (AA) and cognitive alexithymic (CA) participants, selected on the basis of the Toronto Alexithymia Scale and the Bermond-Vorst Alexithymia Questionnaire. All participants responded to questionnaires of empathy, social phobia, depression, and anxiety before the experiment and evaluated the arousal of the pictures after it. Results: Cognitive alexithymic group showed lower amplitudes of SCRs to pictures with social than without social relevance whereas the opposite pattern was observed for the NA group. Arousal emotional effects of the pictures on SCRs did not differ among groups. In addition, CA participants showed lower scores than NA in the Personal Taking sub-scale of the empathy questionnaire, while AA showed lower scores than NA in the fantasy sub-scale. The CA group showed higher social phobia, depression and anxiety scores, than the other two groups. Conclusion: This work has two original outcomes: first, affective alexithymics expressed lower empathic affective scores than other groups; second, alexithymia modulated the impact of the social relevance of the stimuli on the autonomic reactivity, this impact vanishing in affective alexithymics and reversing in cognitive alexithymics. Thus, though the groups could not be distinguished on the basis of emotional effect on SCRs, they clearly differed when the empathic characteristics and the autonomic impact of social relevance were considered. Finally, the described autonomic signature to social relevant information could contribute to elucidate the difficulty of alexithymics to deal with emotions during social transactions.

Reduced anticipation of negative emotional events in alexithymia

Alexithymia is characterized by difficulties in different domains of emotion processing, especially in relation to negative emotions. Nevertheless, its causal mechanisms remain elusive. Reduced anticipation of negative emotional events might be one such mechanism because it enables the individual to prepare to respond effectively to coming events. To test this, changes in skin conductance response (SCR) were recorded during classical fear conditioning in sixty participants with high (HA), medium (MA) and low (LA) levels of alexithymia. Two coloured squares were presented, one was reinforced with a mild electrical stimulation (CS+) while the other was never reinforced (CS−). Critically, despite all groups showing higher SCR to CS+ compared to CS−, SCR to CS+ was lower and extinguished earlier in HA compared to MA and LA. These differences appeared to be attributable neither to differences in the intensity of stimulation received, nor to SCR to the stimulation itself. Groups showed comparable SCR to CS− as well. Therefore, HA exhibited decreased anticipation of the occurrence of a negative emotional event. Disruption of this mechanism may then compromise effective emotion recognition, emotional response and response regulation, which characterise HA, and represent a unifying causal mechanism underlying the difficulties in emotion processing of this group.

Atypical sympathetic arousal in children with autism spectrum disorder and its association with anxiety symptomatology

Background

Autism spectrum disorder (ASD) has been associated with autonomic atypicalities, although the nature of these differences remains largely unknown. Moreover, existing literature suggests large variability in autonomic function in ASD, motivating the need to examine the existence of subgroups that exhibit more homogeneous autonomic features.

Methods

Electrodermal activity (EDA), a non-invasive physiological indicator of autonomic activity, was measured in typically developing children (n = 33) and those with ASD (n = 38) as participants performed tasks that elicit anxiety, attention, response inhibition, and social cognition processes. The ASD group was divided into low- (n = 18) and high-anxiety (n = 20) participants, and the groups were compared to mean EDA level and electrodermal reactions frequency (EDR).

Results

The ASD group had a significantly blunted mean EDA response to the anxiety tasks (p < 0.004). The EDR response to all tasks, except response inhibition, was also blunted in the ASD group (p < 0.04). For this group, EDR frequency during the anxiety and social cognition tasks was negatively correlated with behavioral scores in the domains that were probed by each task (p < 0.002). The high-anxiety ASD group showed significantly decreased mean EDA compared to both the low-anxiety ASD group (p = 0.02) and the typically developing control group (p = 0.04). The high-anxiety ASD group also had significantly more severe symptoms than the low-anxiety ASD group on domains related to anxiety, attention, rule breaking, aggression, obsessions and compulsions, and depression.

Conclusions

Our results suggest atypical autonomic function in children with ASD, specifically with respect to sympathetic activity. Moreover, anxiety symptomatology defined subgroups with distinct physiological and behavioral profiles. Overall, the results add to the body of literature supporting autonomic dysfunction in ASD and highlight the role of anxiety and autonomic features in explaining the variability in the autism spectrum.

Development of alexithymic personality features

The purpose of this paper is to review the current literature regarding the development of alexithymic personality features. Modern brain imaging technologies provide interesting data on the associations of alexithymia with different aberrations in brain function related to emotion regulation; however, the development of these deviations is poorly understood. A notable amount of research covers the relation of alexithymia to different environmental factors. Many of these associations, for example, with low socio-economic status and general psychopathology in childhood, are well established. However, the retrospective and cross-sectional designs commonly used in these studies, as well as the use of self-report measures, hinder the ability to firmly establish causality. Certain individual developmental factors, such as lagging speech development and congenital cardiac malformations in childhood, have been associated with the development of alexithymia. Regarding the stability of alexithymia, a systematic review of the literature was conducted for this paper. In addition to being characterized as a personality feature in the general population, alexithymia also clearly has a state-like dimension that results in increases and decreases in alexithymic features in conjunction with mental disorder symptoms. An essential question is whether the alexithymic features in adulthood are, in fact, infantile features of a restricted ability to identify and describe emotions that simply persist in individuals through adolescence to adulthood. To firmly establish the roots of alexithymia development, longitudinal studies, particularly in younger populations, are needed. Furthermore, multifaceted study settings are encouraged.

A Behavior Analytic Interpretation of Alexithymia

Alexithymia is a term used to describe individuals who seem unable to experience or at least describe emotions. This paper offers a theoretical interpretation of alexithymia from a radical behaviorist perspective. While there have been attempts to explain the etiology of alexithymia, the current analysis is unique in that it provides direct treatment implications. The pragmatic analysis described focuses on the verbal behavior of individuals rather than looking "inside" for explanations. This is supported by a review of experimental research that has failed to find consistencies among alexithymic individuals' physiological responding. Descriptions of the various discriminative and consequential stimulus conditions involved in the complex learning histories of individuals that could result in an alexithymic presentation are provided. This analysis helps situate the alexithymia construct in a broader behavior analytic understanding of emotions. Finally this paper outlines implications for assessment and treatment, which involve influencing discriminative and consequential interpersonal stimulus conditions to shape verbal behavior about emotions.

Brain potentials to emotional pictures are modulated by alexithymia during emotion regulation

Alexithymia is a personality trait associated with the reduced ability to regulate, identify, and communicate feelings or emotions and is often linked to psychosomatic disorders. The present study used event-related potentials (ERPs) to investigate the relationship between individual differences in alexithymia and emotion regulation. Participants classified as scoring either high or low on the revised form of the Toronto Alexithymia Scale (TAS-20; Taylor, Bagby, & Parker Psychother Psychosom 57:34-41, 1992) were asked to view negative and neutral images, adopting three different regulation strategies (expressive suppression, cognitive reappraisal, and attend) while ERPs were recorded. Results revealed an inverse relationship between TAS scores and emotion-related ERP activity during suppression, but not during reappraisal or a control "attend" condition. These results were observed in both early and late ERP latencies. These findings are interpreted according to potential differences between high- and low-TAS individuals regarding the frequency of prior utilization of suppression-based regulation strategies.

Cognitive and physiological dissociations in response to emotional pictures in patients with anorexia

Recent studies suggest that patients with anorexia may express dissociated cognitive and physiological reactivities to emotional stimuli. The present research aimed to compare subjective and autonomic responses to pleasant, unpleasant and neutral scenes during a categorization task and an activation rating task in anorexic (AN), alexithymic (AL), depressed (DEP) and control participants (CONT). The participants first categorized pictures according to their emotional valence, followed by a rating of their activation level, concomitant with the recording of skin conductance responses (SCRs). Main findings showed that the AN patients presented major difficulty in categorizing pictures, particularly neutral ones. Contrary to the AL participants, this difficulty did not induce significant increases of SCR amplitude in the AN patients. In the second task, the AN patients rated the intensity of activation of unpleasant pictures higher than the AL participants and that of pleasant ones higher than the AL and CONT participants. In addition, no significant linear correlation was observed between the intensity of activation ratings and SCR amplitude in the AN, AL or DEP participants contrarily to what was observed for control participants. This lack of relation suggests a non-specific disconnection between physiological and cognitive self-reported responses to emotional stimuli. Our results highlight a specific form of emotional processing in the AN patients distinct from that observed in alexithymia or depression and characterized by a dissociation between cognitive and physiological responses. This kind of disconnection could be associated with emotional regulation processes and may benefit the AN patients by lowering the psychological stress response.

Alexithymia, depression and heart rate in candidates for cardiac surgery

Effects of psychological traits on heart rate (HR) and heart rate variability (HRV) were evaluated in patients awaiting cardiac surgery. Alexithymics demonstrated slowed HR, whereas high cognitive performance was associated with elevated HR in 2-3 days before surgery. Depression negatively correlated with HRV low frequency power. These data are consistent with previous findings of diverse moderate stress effects on HR regulation in cardiologic patients and healthy subjects in accordance to differences in psychological characteristics.

Alexithymia in the German general population

The Toronto-Alexithymia-Scale (TAS-20) is used worldwide as a valid measurement of alexithymia. Until now, population-based standardization and cut-off values of the German TAS-20 version have not been available. This study provides these by means of a representative German sample and by investigating the factorial structure of the TAS-20. Data were generated from a representative random sample of the German general population (1,859 subjects aged between 20 and 69). The TAS-20 sum score was normally distributed. The mean value was 49.5 (SD=9.3) in men and 48.2 (SD=9.2) in women. Divorce, single and low social status were associated with enhanced sum scores. Ten percent of the population exceeded the TAS-20 sum score threshold of >or=61. The 66th percentile reached 53 for men and 52 for women. Factor analysis identified three factors that match the scales of the English original version. An additional fourth factor ("importance of emotional introspection") was extracted. Total explanation of variance by these four factors was 52.27%. The sum score of the German TAS-20 version is suited for the standardized measure of alexithymia. For selecting alexithymic individuals in experimental studies, the cut-off >or=61 is possibly too restrictive. Therefore, we propose the 66th percentile for the identification of high alexithymics. The TAS-20 sum score is associated with important socio-demographic variables. The factorial structure is reliable; the fourth factor ("importance of emotional introspection") provides differentiation of content and allows for enhanced explanation of variance.

Cortical augmenting in alexithymic subjects after unpleasant acoustic stimulation

OBJECTIVE

Alexithymia has a high prevalence in patients with chronic or somatoform pain disorders. Various investigations demonstrated a hypersensitivity and low tolerance of alexithymics to touch and painful stimulation. It was argued that alexithymic characteristics may lead an individual to augment stimuli in order to prevent ignoring stimuli that might be dangerous. Therefore, there may be a relation to the reducer-augmenter construct. To test this hypothesis, cortical reactivity in response to unpleasant acoustical stimulation was measured.

METHODS

Nineteen high alexithymics and 18 low alexithymics were stimulated with five series of acoustic stimuli (white noise) of different intensity levels. Evoked potentials were recorded at electroencephalogram electrodes Fz, Cz, and Pz.

RESULTS

With ascending stimulus intensities, both groups showed increasing P1-N1 and N1-P2 peak-to-peak amplitudes. High alexithymics had higher P1-N1 amplitudes and a stronger intensity-dependent slope of P1-N1 amplitude. In contrast to that, N1-P2 amplitude of low alexithymics tended to decrease in response to the highest stimulus intensity level.

CONCLUSION

High alexithymic subjects seem to behave like cortical augmenters. This may be due to a disturbed transmarginal inhibition, which may normally serve as a protective physiological mechanism.

Verbal-autonomic response dissociations as traits?

Dissociations between subjective and physiological responses to stress are of central interest in coping research. However, little is known about their stability across situations and time. Two experimental sessions - separated by 1 year - were conducted to examine cross-situational consistency and longterm-stability of HR-derived and SCL-derived dissociation scores. In year 1, a speech stressor, the cold pressor and a video stressor (viewing of the speech video) were applied. In year 2, mental arithmetics, anagrams and a torture video were presented. Thirty-five students participated and HR, SCL and negative affect were recorded. For each stressor, standardized changes in negative affect were subtracted from changes in autonomic reactivity (HR and SCL, respectively). Dissociation scores were relatively consistent across the stressors with HR-derived scores exceeding SCL-derived scores. Longterm-stability proved acceptable (r=.61, P<.001 for HR-derived and r=.40, P<.05 for SCL-derived scores). In sum, verbal-autonomic response dissociations show considerable cross-situational and temporal stability and thus might be considered as traits.