Chronotype, daily affect and social contact: An ecological momentary assessment study.

Eveningness is associated with lower daily positive affect (PA). The relationship between negative affect (NA) and chronotype, however, is less consistent in the literature. Eveningness may be further characterized by increased social isolation, which could explain the associations between chronotype and PA/NA. In the present longitudinal study, we used ecological momentary assessment (EMA) to investigate the associations of chronotype with daily PA, NA, and social contact in individuals with current and remitted major depressive disorder (MDD) and healthy controls. As part of the Netherlands Study of Depression and Anxiety (NESDA), 279 participants (n = 49 depressed, n = 172 remitted, n = 58 controls) monitored daily PA, NA, and social contact (i.e., being alone vs. with others) for two weeks, five times per day. Overall, eveningness was associated with less social contact. This effect became nonsignificant, however, after accounting for sociodemographics (gender, age, education, living situation). Chronotype was not related to PA or NA. Less social contact was associated with lower PA and higher NA independent of chronotype. In conclusion, we could not replicate the finding of lower PA among evening types, but found social contact to associate with both daily PA and NA.

From ear to eye? No effect of transcutaneous vagus nerve stimulation on human pupil dilation: A report of three studies.

Transcutaneous stimulation of the auricular branch of the vagus nerve (tVNS) has been proposed as a treatment for a spectrum of physical and psychological disorders. One of the proposed working mechanisms of tVNS is a modulatory effect on the locus coeruleus - noradrenaline (LC-NA) network. We tested this hypothesis in humans in a series of three studies: one focusing on high trait worriers, and two in healthy populations. In all three studies, we tested whether tVNS increases resting pupil diameter - as an index of LC-NA network activity. Additionally, we tested whether tVNS affects task performance and task-related pupil dilation during an Attentional Blink task. We found no evidence that tVNS increases pupil diameter or task-related pupil dilation in any of the tasks. No consistent effects of tVNS on performance on the attentional blink task were found. Overall, the results of these studies indicate that tVNS does not affect these behavioral and physiological indices of noradrenergic activity.

The effect of transcutaneous vagus nerve stimulation on fear generalization and subsequent fear extinction.

Fear overgeneralization is thought to be one of the cardinal processes underlying anxiety disorders, and a determinant of the onset, maintenance and recurrence of these disorders. Animal studies have shown that stimulating the vagus nerve (VNS) affects neuronal pathways implicated in pattern separation and completion, suggesting it may reduce the generalization of a fear memory to novel situations. In a one-day study, 58 healthy students were subjected to a fear conditioning, fear generalization, and fear extinction paradigm. Participants were randomly assigned to receive either transcutaneous auricular VNS (tVNS; final N = 29) or sham stimulation (final N = 29) during the generalization and extinction phases. tVNS did not affect fear generalization, as reflected by US expectancy ratings and fear potentiated startle responses. However, participants who received tVNS reported lower US expectancy ratings to the CS+ during the extinction phase, possibly reflecting a stronger declarative extinction of fear. No effects of tVNS on fear potentiated startle responses during extinction were found. The pattern of findings regarding extinction of declarative fear suggest a facilitating effect of tVNS.

Transcutaneous vagus nerve stimulation reduces spontaneous but not induced negative thought intrusions in high worriers.

Worrying is a central component of anxiety disorders. We tested whether non-invasive vagus nerve stimulation reduces negative thought intrusions in high worriers. Worry was assessed with a Breathing Focus Task, which consists of a pre-worry period, a worry induction, and a post-worry period. Ninety-seven high worriers were randomly allocated to receive transcutaneous electrical stimulation of the auricular branch of the vagus nerve at the concha (tVNS), or of the earlobe (sham stimulation) throughout the lab session. Participants who received tVNS reported significantly fewer negative thought intrusions during the pre-worry period, but the effects of tVNS after the worry induction were mixed. An exploratory analysis indicated that participants in the tVNS condition were more likely to report negative thought intrusions shortly after the worry induction, but became less likely to do so as the post-worry period went on. No effects of tVNS on RMSSD were observed. These findings provide preliminary indications that tVNS may decrease the occurrence of worrisome thoughts.

Heart rate variability as candidate endophenotype of social anxiety: A two-generation family study.

BACKGROUND: Social anxiety disorder (SAD) is the extreme fear and avoidance of one or more social situations. The goal of the current study was to investigate whether heart rate variability (HRV) during resting state and a social performance task (SPT) is a candidate endophenotype of SAD. METHODS: In this two-generation family study, patients with SAD with their partner and children, and their siblings with partner and children took part in a SPT (total n = 121, 9 families, 3-30 persons per family, age range: 8-61 years, 17 patients with SAD). In this task, participants had to watch and evaluate the speech of a female peer, and had to give a similar speech. HRV was measured during two resting state phases, and during anticipation, speech and recovery phases of the SPT. We tested two criteria for endophenotypes: co-segregation with SAD within families and heritability. RESULTS: HRV did not co-segregate with SAD within families. Root mean square of successive differences during the first resting phase and recovery, and high frequency power during all phases of the task were heritable. LIMITATIONS: It should be noted that few participants were diagnosed with SAD. Results during the speech should be interpreted with caution, because the duration was short and there was a lot of movement. CONCLUSIONS: HRV during resting state and the SPT is a possible endophenotype, but not of SAD. As other studies have shown that HRV is related to different internalizing disorders, HRV might reflect a transdiagnostic genetic vulnerability for internalizing disorders. Future research should investigate which factors influence the development of psychopathology in persons with decreased HRV.

Mixed evidence for the potential of non-invasive transcutaneous vagal nerve stimulation to improve the extinction and retention of fear.

Extinction memories are fragile and their formation has been proposed to partially rely on vagus nerve activity. We tested whether stimulating the auricular branch of the vagus (transcutaneous VNS; tVNS) accelerates extinction and reduces spontaneous recovery of fear. Forty-two healthy students participated in a 3-day fear conditioning study, where we tested fear acquisition (day 1), fear extinction (day 2) and the retention of the extinction memory (day 3). During extinction, participants were randomly allocated to receive tVNS or sham stimulation concurrently with each CS presentation. During the acquisition and retention phases, all participants received sham stimulation. Indexes of fear included US-expectancy, startle blink EMG and skin conductance responses. Results showed successful acquisition and extinction of fear in all measures. tVNS facilitated the extinction of declarative fear (US expectancy ratings), but did not promote a stronger retention of the declarative extinction memory. No clear effects of tVNS on extinction and retention of extinction were found for the psychophysiological indexes. The present findings provide tentative indications that tVNS could be a promising tool to improve fear extinction and call for larger scale studies to replicate these effects.

Does unconscious stress play a role in prolonged cardiovascular stress recovery?

According to recent insights, humans might not be aware of a substantial part of their cognitive stress representations while these still have prolonged physiological effects. 'Unconscious stress' can be measured by implicit affect (IA) tests. It was shown that IA predicts physiological stress responses, in fact better than explicit ('conscious') affect. It is not known yet whether IA is associated with concurrent prolonged stress responses. In two studies (n = 62 and 123), anger harassment was used to induce stress. Blood pressure (BP) and heart rate (HR) were measured continuously. During BP and HR recovery, IA was measured by an 'anger' version of the implicit association test (IAT) or the implicit positive and negative affect test (IPANAT). Blood pressure and HR increased during anger harassment and recovery afterwards. When using the IPANAT BP recovery levels were lower when positive IA was high and higher when negative IA was high, independent of explicit affect and rumination. These results were not found using the IAT. These results provide preliminary evidence that physiological stress recovery is associated with IA. This is in line with the theory that unconscious stress is responsible for a-possibly considerable-part of unhealthy prolonged stress-related physiological activity.

Goal commitment to finding a partner and satisfaction with life among female singles: the mediating role of rumination.

In this cross-sectional study among 1502 female singles between the ages of 18 and 50, commitment to the goal of finding a partner was negatively related to satisfaction with life. In line with our expectations, this relationship was fully mediated by ruminating about being and remaining single. The relationship between rumination and lower satisfaction with life was stronger in the older age groups. The findings support the notion that rumination is an important mechanism through which goal commitment may negatively influence well-being, and that reducing one's level of commitment to the pursuit of stage-specific life goals may be beneficial when reaching a new developmental stage.