Social reward from giving food to others affects food craving and brain potentials: An imagery-based event-related potential study.

The interactions between social and eating behaviors can be quite pronounced and are mediated by overlapping neural circuits. The present event-related potential study tested whether the imagery of a specific prosocial behavior (giving chocolates to grateful children) can influence food cue reactivity. A total of 92 females (mean age = 23.5 years) were randomly assigned to one of three guided imagery conditions. The participants listened to an audio recording and were instructed to imagine one of three possible scenes; giving 30 M&Ms to children, eating 30 M&Ms, or sorting 30 marbles. Directly after the imagery task, the participants were presented with images of M&Ms and marbles while their electroencephalogram was recorded. We examined the Late Positive Potential (LPP) across a fronto-central and a parieto-occipital cluster, M&M craving, and subsequent consumption of (real) M&Ms. The mental imagery of offering M&Ms to children was associated with lower M&M craving and higher fronto-central LPP amplitudes (300-600 ms after picture onset) compared to the other imagery conditions. The consumption of M&Ms did not differ between the groups. The LPP is sensitive to the implementation of craving regulation strategies. Furthermore, heightened LPPs are reliably observed in response to motivationally significant stimuli, conflict, and social context. Future studies are needed to specify the specific psychological processes that are associated with the observed LPP effect. In conclusion, this study demonstrated that mental imagery of receiving a social reward from giving food to others can change components of food cue reactivity in healthy females.

The association between the belief in coronavirus conspiracy theories, miracles, and the susceptibility to conjunction fallacy.

Previous research has shown that people who endorse conspiracy theories are more prone to the conjunction fallacy: the tendency to perceive conjunct events as more probable than constituent events. The present study examined the relationship between specific beliefs (belief in conspiracy theories, religiosity) and the susceptibility to conjunction errors (CEs) in specific domains. A total of 500 participants was presented with brief scenarios from the domains "coronavirus conspiracy," "miraculous healing," and a control condition. Each scenario included one statement about a separate event and a second statement about two joint events co-occurring. The participants estimated the probability of each statement. Results showed that the number of CEs made in the coronavirus domain was only associated with the belief in conspiracy theories, while general religiosity was only associated with CEs for scenarios describing miraculous healings. The assessed beliefs were not associated with CEs made in the control condition. Results suggest that distinct beliefs are uniquely associated with the susceptibility to conjunction errors in particular domains.

Changing the visualization of food to reduce food cue reactivity: An event-related potential study.

Visual food cues automatically capture our attention. Moreover, food cue exposure is associated with an increased desire to eat (craving) and food consumption. We attempted to reduce the attentional bias to images depicting a specific food (M&Ms), craving, and consumption through mental imagery in a sample of 98 females (mean age = 23.82 years). The participants either listened to a guided imagery script that described the crushing of M&Ms to reduce the appetitive value of the chocolates, or they envisioned the sorting of M&Ms, or marbles (as control conditions). Afterward, participants were presented with images of M&Ms (not crushed) and marbles while their electroencephalogram, craving ratings, and M&M consumption were measured. The visualization of crushing M&Ms was associated with increased early (P200) and late positivity (P300, early LPP) to M&M pictures, which indicate automatic (P200/P300) and deliberate attention (LPP). M&M sorting increased craving but did not influence M&M consumption. Our findings show that imaginary M&M crushing cannot reduce attention to M&M images and even has the opposite of the intended effect.

Placebo Effects in the Context of Religious Beliefs and Practices: A Resting-State Functional Connectivity Study.

Background: Placebos (inert substances or procedures) can positively influence a person's psychological and physical well-being, which is accompanied by specific changes in brain activity. There are many different types of placebos with different effects on health-related variables. This study investigated placebo effects in the context of religious beliefs and practices. The participants received an inert substance (tap water) along with the verbal suggestion that the water would come from the sanctuary in Lourdes (a major Catholic pilgrimage site with reports of miracle cures). We investigated changes in resting-state functional connectivity (rsFC) in three brain networks (default-mode, salience, cognitive control) associated with the drinking of the placebo water. Methods: A total of 37 females with the belief that water from the sanctuary in Lourdes has positive effects on their spiritual, emotional, and physical well-being participated in this placebo study with two sessions. The participants drank tap water that was labeled "Lourdes water" (placebo) before a 15-min resting-state scan in one session. In the other (control) session, they received tap water labeled as tap water. The participants rated their affective state (valence, arousal) during the session and were interviewed concerning specific thoughts, feelings, and bodily sensations directly after each of the two sessions. Results: The placebo reduced rsFC in the frontoparietal cognitive control network and increased rsFC in the salience network (insular-cerebellar connectivity). During the session, the participants rated their affective state as very pleasant and calm. The ratings did not differ between the two conditions. Immediately after the session, the participants reported increased intensity of pleasant bodily sensations (e.g., feelings of warmth, tingling) and feelings (e.g., gratefulness) for the "Lourdes water" condition. Conclusions: The present findings provide the first evidence that placebos in the context of religious beliefs and practices can change the experience of emotional salience and cognitive control which is accompanied by connectivity changes in the associated brain networks.

Placebos can change affective contexts: An event-related potential study.

An unpleasant context (bitter aftertaste) is able to reduce the late positive potential (LPP) elicited by affective pictures. This study attempted to influence this context with a placebo. Sixty-eight women were randomly assigned to three groups: Water, Bitter/No-Placebo, Bitter/Placebo. Participants in the 'bitter groups' first rinsed their mouth with wormwood tea that caused a bitter aftertaste. Subsequently, the placebo group received sham light therapy on the tongue to 'reduce the sensitivity of the taste buds'. All groups viewed disgusting and non-disgusting pictures while their electroencephalogram was recorded. The Bitter/Placebo group reported reduced bitterness and disgust for the aftertaste after the sham treatment. The LPP reduction (300-600 ms after picture onset) associated with the bitter aftertaste (as shown by the Bitter/No-Placebo group) was attenuated due to the placebo treatment. This is the first EEG study to demonstrate that a context-targeting placebo is able to change automatic attention allocation.

Interaction between disgust proneness and perception of treatment efficacy predicts response to a disgust placebo.

Placebo responsiveness is highly variable across individuals and has been shown to be difficult to predict solely based on personality traits. The present study examined the interaction between a specific trait and state variable (disgust proneness and perceived effectiveness of a disgust placebo) on placebo responsiveness. We presented 145 participants with an inert pill, which was introduced as an effective anti-nausea drug. Disgust responses were elicited by a validated picture set, which was viewed once with and once without the disgust placebo. The results showed that the placebo was effective in reducing experienced disgust. When predicting placebo responsiveness, the results showed a significant interaction between perceived treatment effectiveness and disgust proneness. Specifically, effectiveness ratings were a significant predictor of placebo response only for individuals high in disgust proneness. The results suggest that the joint consideration of specific state and trait factors can be used to optimize placebo responsiveness.

Altered grey matter volume in 'super smellers'.

'Super smellers' are those individuals who show a heightened sense of smell. Data on the structural neuroanatomy of this phenomenon are still missing. A voxel-based morphometry study was conducted in order to compare gray matter volume (GMV) in specific brain regions of the olfactory network (piriform/entorhinal cortex, orbitofrontal cortex, insula, hippocampus) between 25 male 'super smellers' and 20 normosmic men. Participants were assigned to these groups based on their scores on a standardized olfactory performance test. Relative to normosmic men, 'super smellers' showed increased GMV in the anterior insula and in the hippocampus (dentate gyrus). These regions are crucial for the integration of olfactory information as well as odor learning and odor memory. Moreover, positive correlations between hippocampal volume and olfactory performance were detected in both groups. Future research should elaborate on how much of the observed neuroanatomical pattern of 'super smellers' is genetic and how much of it reflects experienced-based GMV increase.

Nocebo and pseudo-neglect: Paradoxical effects detected with eye-tracking.

The knowledge about effects of placebos and nocebos on specific visual attention processes is still very limited. In the present eye-tracking study, it was analyzed if a nocebo (sham transcranial magnetic stimulation) is able to elicit left-sided attentional deficits (pseudo-neglect). Fifty-two healthy participants performed a search task on the computer, once with and once without the nocebo. Indicators of left-biased search behavior (e.g. fixation count, reaction times for left vs. right-sided target detection) and affective state (e.g., valence, arousal) were assessed. The sample was divided into two groups (nocebo responder, non-responder) based on the experienced effectiveness of the nocebo. The nocebo treatment was associated with a positive and calm affective state. Contrary to the verbal suggestion, the nocebo increased the number of fixations and the dwell time on the left side of the computer screen. Moreover, the nocebo decreased the detection time for targets on the left side. These paradoxical nocebo effects were restricted to nocebo responders. Possible implications of nocebo-related compensatory behaviors for neuropsychological therapy are discussed.

Placebo effects in spider phobia: an eye-tracking experiment.

Several eye-tracking studies have revealed that spider phobic patients show a typical hypervigilance-avoidance pattern when confronted with images of spiders. The present experiment investigated if this pattern can be changed via placebo treatment. We conducted an eye-tracking experiment with 37 women with spider phobia. They looked at picture pairs (a spider paired with a neutral picture) for 7 s each in a retest design: once with and once without a placebo pill presented along with the verbal suggestion that it can reduce phobic symptoms. The placebo was labelled as Propranolol, a beta-blocker that has been successfully used to treat spider phobia. In the placebo condition, both the fixation count and the dwell time on the spider pictures increased, especially in the second half of the presentation time. This was associated with a slight decrease in self-reported symptom severity. In summary, we were able to show that a placebo was able to positively influence visual avoidance in spider phobia. This effect might help to overcome apprehension about engaging in exposure therapy, which is present in many phobic patients.

Testing the effects of a disgust placebo with eye tracking.

Previous neuroimaging research showed that a disgust placebo (inert pill presented with the verbal suggestion of disgust relief) reduced visual cortex activation during the viewing of disgust-inducing images. In order to investigate whether this effect of automatic emotion regulation was associated with changed visual scanning patterns of the pictures, we conducted two eye tracking experiments. In the first study, 23 women underwent a retest design during which they passively viewed images depicting disgusting, fear-eliciting, neutral items and fractals both with, and without a placebo. The placebo provoked a substantial decrease in experienced disgust. Although none of the recorded eye movement parameters (number of fixations, fixation duration, saccade amplitude, blinking rate) showed placebo-related changes, placebo effects were suggested by an analysis of spatial fixation patterns. In the second study, which focused on attentional (dis)engagement, 46 women looked at two pictures which were presented side-by-side on the screen. These picture pairs (disgust-neutral, neutral-neutral) were once viewed with and once without a placebo. The placebo again provoked a marked decrease of experienced disgust and enhanced the number of fixations for disgusting images. This change might reflect a greater willingness of the participants to view these stimuli while on the placebo.