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The nature of the global signal, i.e. the average signal from sequential functional imaging scans of the brain or the cortex, is not well understood, but is thought to include vascular and neural components. Using resting state data, we report on the strong association between the global signal and the average signal from the part of the volume that includes the cranial bone and subdural vessels and venous collectors, separated from each other and the subdural space by multispectral segmentation procedures. While subdural vessels carried a signal with a phase delay relative to the cortex, the association with the cortical signal was strongest in the parts of the scan corresponding to the laminae of the cranial bone, reaching 80% shared variance in some individuals. These findings suggest that in resting state data vascular components may play a prominent role in the genesis of fluctuations of the global signal. Evidence from other studies on the existence of neural sources of the global signal suggests that it may reflect the action of multiple mechanisms (including cerebrovascular reactivity and autonomic control) concurrently acting to regulate global cerebral perfusion.

Background: Conspiracy theory belief – explaining the ultimate causes of social and political events with claims of secret conspiracies – is assumed to arise from a desire to make sense of uncertainty, especially in times of crisis. However, there is no compelling evidence that conspiracy theory belief actually fulfils this function, particularly in terms of evaluating one's life as meaningful. We posit that the adoption of conspiracy theory belief can be explained as a fluid compensation when a more proximal source of meaning, a sense of belonging to society, is threatened. Thus, a positive association between conspiracy theory belief and meaningfulness should emerge when people feel alienated from society. We therefore tested the hypotheses that alienation from society correlates negatively with meaningfulness (H1), and that it moderates the relationship between conspiracy theory belief and meaningfulness (H2). Method: Conspiracy theory belief related to the COVID-19 pandemic, meaningfulness (Meaning and Purpose Scales, MAPS), and perceived alienation from society were assessed in a representative sample of N = 974 German residents. Results: As expected, alienation from society was inversely related to meaningfulness and moderated the relationship between conspiracy theory belief and meaningfulness. According to the interaction, a positive association between belief in conspiracy theory and meaningfulness emerged when individuals experienced themselves as alienated from society. Conclusion: The results suggest that conspiracy theory belief might alleviate a lack of meaningfulness caused by experienced alienation from society. Individuals who felt discriminated against, treated unequally, or having their rights restricted were more likely to hold conspiracy theory belief, which was associated with a greater sense of meaning in their lives.

Functional imaging studies of sensory decision making have detected a signal associated with evidence for decisions that is consistent with data from single-cell recordings in laboratory animals. However, the generality of this finding and its implications on our understanding of the organization of the fMRI signal are not clear. In the present functional imaging study, we investigated decisions in an elementary social cognition domain to identify the neural correlates of evidence, their segregation, connectivity, and their relationship to task deactivations. Besides providing data in support of an evidence-related signal in a social cognition task, we were interested in embedding these neural correlates in models of supramodal associative cortex placed at the top of a hierarchy of processing areas. Participants were asked to decide which of two depicted individuals was saddest based on information rich in sensory features (facial expressions) or through contextual cues suggesting the mental state of others (stylized drawings of mourning individuals). The signal associated with evidence for the decision was located in two distinct networks differentially recruited depending on the information type. Using the largest peaks of the signal associated with evidence as seeds in a database of connectivity data, these two networks were retrieved. Furthermore, the hubs of these networks were located near or along a ribbon of cortex located between task activations and deactivations between areas affected by perceptual priming and the deactivated areas of the default network system. In associative cortex, these findings suggest gradients of progressive relative deactivation as a possible neural correlate of the cortical organization envisaged by structural models of cortical organization and by predictive coding theories of cortical function.

Treatment with interferon (IFN) has been associated with depressive side effects. Previous neuroimaging studies have provided information about changes in brain activation patterns in patients under treatment with IFN-alpha, but the effect of other IFNs, or the role of the underlying disease, has yet to be clarified. In the present fMRI study, we looked at brain changes after 8 days of IFN-beta treatment in N = =17 healthy volunteers, thus avoiding the possible confound of the effects of underlying pathology in studies of IFN-treated patients with neurological or other medical disorders. We followed a symptom dimensional approach by simultaneously investigating two distinct symptom domains of depressiveness: negative affect (amygdala) and appetitive motivation (ventral striatum). In these early phases of IFN treatment we detected a selective change in neural substrates of appetitive motivation, consistent with the predominant symptomatic change recorded in psychopathology ratings. In contrast, the fMRI phenotype of negative affect, which is known to characterize disorders of affect involving anxiety and depressiveness as well as individual vulnerability to depression, was unchanged after treatment. These findings suggest that IFN may induce an affective syndrome through a mechanism involving down-regulation of appetitive motivation.

Borderline personality disorder (BPD) is characterized by pronounced emotional instability in interpersonal relations. Previous studies have shown increased activity in the amygdala, an imaging phenotype of negative affect. However, clinical accounts of BPD have drawn attention to deficits in social cognition and their likely role in engendering emotional instability. BPD patients show enhanced sensitivity to other people's emotions, while being less proficient in reading motives and reasons. In the present functional imaging study, we exposed BPD participants to stylized scenes of individuals affected by loss or separation, an issue to which these patients are particularly sensitive. Previously shown to activate the mirror neuron system, these mourning scenes were here also used to assess differential amygdala activity in stimuli of negative valence, but low arousal. Relative to controls, BPD patients were found to activate sensorimotor areas, a part of the mirror neuron system thought to encode basic aspects of the perception of motoric activity and pain. This contrasted with the activity of areas related to more complex aspects of social cognition, such as the inferior frontal gyrus. The amygdala was more active in patients when viewing these scenes, but this effect also showed a strong association with levels of depressiveness and neuroticism. After adjusting for these covariates, differences in amygdala activation were no longer significant. These findings are consistent with models of social cognition in BPD that attribute emotional sensitivity to emotional contagion through the mirror neuron system, in contrast to areas associated with more sophisticated forms of social cognition. These effects were accompanied by increased amygdala reactivity, consistently with the common occurrence of affective symptoms in these patients. Keywords: Borderline personality disorder, Mirror neuron system, Empathy, Neurobiological models of borderline personality disorder, Neuroimaging of borderline personality disorder