The effects of subliminal or supraliminal sadness induction on the sense of body ownership and the role of dissociative symptoms

Previous research has shown that emotions can alter our sense of ownership. Whether this relationship is modulated by differences in emotion experience and awareness, however, remains unclear. We investigated this by comparing the susceptibility to the rubber hand illusion (RHI) between participants who were either exposed to a low-arousing emotion induction (sadness) or placed in a neutral control group. Several factors that might influence this relationship were considered: dissociative symptoms were included to observe if a sadness induction led to a higher RHI score in participants scoring high in dissociation, as a result of detached emotion experience. Whether the level of awareness of the emotion mattered was also tested, as subliminal processing was shown to require less focal attention. Therefore, our sample (N = 122) was divided into three experimental groups: Sad pictures were presented to two of the three groups differing in presentation mode (subliminal: n = 40, supraliminal: n = 41), neutral pictures were presented supraliminally to the control group (n = 41). Additionally, the effects of slow (3 cm/s) and fast (30 cm/s) stroking, applied either synchronously or asynchronously, were examined as the comforting effects of stroking might interfere with the emotion induction. Results showed that the supraliminal sadness induction was associated with a stronger subjective illusion, but not with a higher proprioceptive drift compared to the subliminal induction. In addition, a stronger subjective illusion after fast and synchronous stroking was found compared to slow and asynchronous stroking. A significant proprioceptive drift was detected independent of group and stroking style. Both slow and synchronous stroking were perceived as more comforting than their respective counterparts. Participants with higher dissociative symptoms were more susceptible to the subjective illusion, especially in the supraliminal group in the synchronous condition. We concluded that individual differences in emotion experience are likely to play a role in body ownership. However, we cannot clarify at this stage whether differences in proprioception and the subjective illusion depend on the type of emotion experienced (e.g. different levels of arousal) and on concomitant changes in multisensory integration processes.

Distinct neural mechanisms of emotional processing in prolonged grief disorder

Background Prolonged grief disorder (PGD) has recently been recognized as a separate psychiatric diagnosis, despite controversy over the extent to which it is distinctive from posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). Methods This study investigated distinctive neural processes underpinning emotion processing in participants with PGD, PTSD, and MDD with functional magnetic resonance study of 117 participants that included PGD (n = 21), PTSD (n = 45), MDD (n = 26), and bereaved controls (BC) (n = 25). Neural responses were measured across the brain while sad, happy, or neutral faces were presented at both supraliminal and subliminal levels. Results PGD had greater activation in the pregenual anterior cingulate cortex (pgACC), bilateral insula, bilateral dorsolateral prefrontal cortices and right caudate and also greater pgACC–right pallidum connectivity relative to BC during subliminal processing of happy faces. PGD was distinct relative to both PTSD and MDD groups with greater recruitment of the medial orbitofrontal cortex during supraliminal processing of sad faces. PGD were also distinct relative to MDD (but not PTSD) with greater activation in the left amygdala, caudate, and putamen during subliminal presentation of sad faces. There was no distinction between PGD, PTSD, and MDD during processing of happy faces. Conclusions These results provide initial evidence of distinct neural profiles of PGD relative to related psychopathological conditions, and highlight activation of neural regions implicated in reward networks. This pattern of findings validates current models of PGD that emphasize the roles of yearning and appetitive processes in PGD.

Verbal Insight Revisited: fMRI evidence for early processing in bilateral insulae for solutions with AHA! experience shortly after trial onset

In insight problem solving solutions with AHA! experience have been assumed to be the consequence of restructuring of a problem which usually takes place shortly before the solution. However, evidence from priming studies suggests that solutions with AHA! are not spontaneously generated during the solution process but already relate to prior subliminal processing. We test this hypothesis by conducting an fMRI study using a modified compound remote associates paradigm which incorporates semantic priming. We observe stronger brain activity in bilateral anterior insulae already shortly after trial onset in problems that were later solved with than without AHA!. This early activity was independent of semantic priming but may be related to other lexical properties of attended words helping to reduce the amount of solutions to look for. In contrast, there was more brain activity in bilateral anterior insulae during solutions that were solved without than with AHA!. This timing (after trial start / during solution) x solution experience (with / without AHA!) interaction was significant.The results suggest that a) solutions accompanied with AHA! relate to early solution-relevant processing and b) both solution experiences differ in timing when solution-relevant processing takes place. In this context, we discuss the potential role of the anterior insula as part of the salience network involved in problem-solving by allocating attentional resources.

Masked Primes Can Be Genuinely Semantically Processed

Van den Bussche and Reynvoet (2007) argued that since significant priming was observed for novel primes from a large category, subliminal primes can be processed semantically. However, a possible confound in this study was the presence of nonsemantic effects such as orthographic overlap between primes and targets. Therefore, the first aim of this study was to validate our previous claim when nonsemantic influences are avoided. The second aim was to investigate the impact of nonsemantic stimulus processing on priming effects by manipulating target set size. The results showed that when nonsemantic effects are eliminated by presenting primes as pictures and targets as words, significant priming emerged for large stimulus categories and a large target set. This cannot be explained by nonsemantic accounts of subliminal processing and shows that subliminal primes can be truly semantically processed. However, when using a limited amount of targets, stimulating nonsemantic processing, priming disappeared. This indicates that the task context will determine whether stimuli will be processed semantically or nonsemantically, which in turn can influence priming effects.