Stefan Wiens

Interoception in emotional experience

Purpose of reviewMany theories of emotion have postulated a close relationship of the feedback of physiological changes and their perception with emotional experience. This paper reviews recent advances in theory and brain-imaging research on this topic of interoception and describes a hypothetical model of the potential mechanisms. Recent findingsResearch from patients with spinal-cord injuries and pure autonomic failure suggests that emotion-related peripheral autonomic changes are not necessary for emotional experience. However, in support of a role for centrally integrated feedback from the whole body, imaging studies found that activations in areas commonly associated with interoception and emotion (anterior insula and anterior cingulate) were correlated with individual differences in interoception (heartbeat detection) and trait measures of emotion. Because recent theory distinguishes between two levels of emotional experience (phenomenology and awareness), this paper proposes a hypothetical model of the effects of interoception on phenomenology and awareness. This model classifies interoception into the central representation of feedback from the whole body, the perception of actual physiological changes as well as the perception of illusory changes. SummaryConsistent with recent theories of emotion, evidence from brain imaging supports the notion that centrally integrated feedback from the whole body plays a role in emotional experience. Because research on neural correlates of emotional experience is at an early stage, the hypothesized model of potential causal links between interoception and emotional experience might serve as a helpful guide to future research.

Stress Recovery during Exposure to Nature Sound and Environmental Noise

Research suggests that visual impressions of natural compared with urban environments facilitate recovery after psychological stress. To test whether auditory stimulation has similar effects, 40 subjects were exposed to sounds from nature or noisy environments after a stressful mental arithmetic task. Skin conductance level (SCL) was used to index sympathetic activation, and high frequency heart rate variability (HF HRV) was used to index parasympathetic activation. Although HF HRV showed no effects, SCL recovery tended to be faster during natural sound than noisy environments. These results suggest that nature sounds facilitate recovery from sympathetic activation after a psychological stressor.

Nonconscious Fear Conditioning, Visceral Perception, and the Development of Gut Feelings

When people are presented with backward-masked images of fear-relevant stimuli and only some of these images are paired consistently with electric shocks, they can predict the occurrence of shocks even though they do not consciously know which images they have seen. We postulated that they may use the perception of visceral cues from the conditional fear response to facilitate the prediction of shocks. In this study, ability to detect heartbeats was used to index sensitivity to visceral cues. The results showed that subjects who could detect their heartbeats performed better than chance in predicting whether or not they would receive a shock during the conditioning task. The findings support the notion that hunches, or “gut feelings,” are based in part on the perception of visceral cues.

Modulation of Emotional Appraisal by False Physiological Feedback during fMRI

Background James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined. Methodology/Principal Findings We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level. Conclusions/Significance Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order “cognitive” representations of bodily arousal state.

Behavioral and ERP indices of response conflict in Stroop and flanker tasks

We investigated effects of different proportions of incongruent trials on behavioral and event-related potential (ERP) interference measures associated with response conflict in the Stroop and flanker task. From the literature, we hypothesized that response conflict is greater when incongruent trials are rare compared to when incongruent trials are frequent. In support, the behavioral results on both tasks and the ERP results on the Stroop task (N450) showed that interference effects were significantly larger when incongruent trials were rare than frequent. In contrast, the ERP results on the flanker task N200 showed a larger interference effect when incongruent trials were frequent than rare. Because results for the flanker N200 were opposite to behavioral effects and theoretical predictions, our findings challenge the notion of the flanker N200 as a valid index of response conflict.

Keeping It Short A Comparison of Methods for Brief Picture Presentation

Research has shown that backward masking is a powerful tool for studying unconscious mental processes. Whereas studies have traditionally presented stimuli using cathode-ray tube (CRT) monitors or mechanical shutters together with slide projectors, recent studies (mainly in functional magnetic resonance imaging, fMRI) have begun to use methods based on liquid crystal displays (LCDs) and thin-film transistor (TFT) technology. However, because of differences in technology, all methods may not be equally suited for masking. When methods were compared for their accuracy in presenting pictures at short durations, LCD and TFT presentations had poor accuracy, but shutter and CRT presentations had better accuracy. Because CRTs interfere with the imaging process in fMRI, we recommend the use of mechanical shutters. However, our results may not generally apply to all displays, so we advise researchers to validate the presentation parameters of their displays. The procedure described here may be useful for that purpose.

Odor identification impairment in carriers of ApoE-ɛ4 is independent of clinical dementia

The ApoE gene is expressed in olfactory brain structures and is believed to play a role in neuronal regenerative processes as well as in development of Alzheimers disease (AD), the most common form of dementia. The varepsilon4 allele has been reported to be associated with compromised odor identification ability in the elderly, and this deficit has been interpreted as a sign of pre-diagnostic AD. However, because it has not been demonstrated that the relationship between the varepsilon4 allele and odor identification is mediated by dementia, it is possible that the varepsilon4 allele may have an effect on odor identification over and above any effects of dementia. The present study investigated effects of ApoE-status on odor identification in a large, population-based sample (n=1236) of adults (45-80 years), who were assessed for dementia at time of testing and 5 years later. The results showed that the varepsilon4 allele was associated with an odor identification deficit among elderly participants (75-80). Critically, this effect remained after current and pre-diagnostic dementia, vocabulary, global cognitive status and health variables were partialled out. The present results suggest that the ApoE gene plays a role in olfactory functioning that is independent of dementia conversion within 5 years.

Current concerns in visual masking.

Theories of emotion postulate that emotional input is processed independently from perceptual awareness. Although visual masking has a long tradition in studying whether emotional pictures are processed below a supposed threshold of perceptual awareness (subliminal perception), a consensus has yet to be reached. This article reviews current concerns in the use of visual masking. These include a reliable presentation method, the role of masking pictures, common definitions of awareness and their problems, current models of awareness, and neural mechanisms. A useful strategy may be the study of dose-response relationships between awareness and emotion processing that avoids a dichotomous view of awareness and allows conclusions about the relative independence of emotional processing from awareness.

Emotionally controlled decision-making and a gene variant related to serotonin synthesis in women with borderline personality disorder

The Iowa Gambling Task (IGT) was used to examine (i) social decision-making in women with borderline personality disorder (BPD), and (ii) the relationship between impaired decision-making and the tryptophan hydroxylase-1 (TPH-1) gene, involved in serotonin synthesis. Forty-two women with BPD and a history of suicide attempts were genotyped, and the frequency of a TPH-1 haplotype previously uniquely associated with BPD was calculated. The BPD group scored significantly lower than a control group in the IGT. Furthermore, the TPH-1 haplotype displayed a significantly higher frequency in BPD participants with impaired decision making, compared to BPD participants with normal scores. These findings suggest that impaired decision-making as determined by the IGT is a feature of BPD and may be (i) associated with serotonin dysfunction, and (ii) possibly relevant for suicidal behavior.

Recognizing Masked Threat: Fear Betrays, But Disgust You Can Trust

If emotions guide consciousness, people may recognize degraded objects in center view more accurately if they either fear the objects or are disgusted by them. Therefore, we studied whether recognition of spiders and snakes correlates with individual differences in spider fear, snake fear, and disgust sensitivity. Female students performed a recognition task with pictures of spiders, snakes, flowers, and mushrooms as well as blanks. Pictures were backward masked to reduce picture visibility. Signal detection analyses showed that recognition of spiders and snakes was correlated with disgust sensitivity but not with fear of spiders or snakes. Further, spider fear correlated with the tendency to misinterpret blanks as threatening (response bias). These findings suggest that effects on recognition and response biases to emotional pictures vary for different emotions and emotional traits. Whereas fear may induce response biases, disgust may facilitate recognition.