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Many studies in affective neuroscience rely on statistical procedures designed to estimate population averages and base their main conclusions on group averages. However, the obvious unit of analysis in affective neuroscience is the individual, not the group, because emotions are individual phenomena that typically vary across individuals. Conclusions based on group averages may therefore be misleading or wrong, if interpreted as statements about emotions of an individual, or meaningless, if interpreted as statements about the group, which has no emotions. We therefore advocate the Single-N design as the default strategy in research on emotions, testing one or several individuals extensively with the primary purpose of obtaining results at the individual level. In neuroscience, the equivalent to the Single-N design is deep imaging, the emerging trend of extensive measurements of activity in single brains. Apart from the fact that individuals react differently to emotional stimuli, they also vary in shape and size of their brains. Group-based analysis of brain imaging data therefore refers to an “average brain” that was activated in a way that may not be representative of the physiology of any of the tested individual brains, nor of how these brains responded to the experimental stimuli. Deep imaging avoids such group-averaging artifacts by simply focusing on the individual brain. This methodological shift toward individual analysis has already opened new research areas in fields like vision science. Inspired by this, we call for a corresponding shift in affective neuroscience, away from group averages, and toward experimental designs targeting the individual.

Background Some aggressive acts committed by individuals with psychotic spectrum disorders (PSD) are understandable in the context of interpersonal conflict or goal attainment, yet others are unpredictable, arising from delusions or hallucinations (psychotically driven aggressive acts, PDA). It is unknown if there are underlying differences in cognitive or perceptive social cognition in relation to aggression motivation in PSD. Method We compared differences in social cognition performance between 49 individuals with PSD who had committed PDA with those exhibiting other types of aggression (n = 31) (non-PDA) and to community controls (n = 81) on the Swedish version of Double Movie for the Assessment of Social Cognition – Multiple Choice (DMASC-MC). Participants with PSD had more than 3 months of clinical stability and substance use abstention and stable antipsychotic medication doses. General intellectual ability was assessed with the information and matrix reasoning subtests of the Wechsler Intelligence Scales. Results The PSD group with a history of PDA exhibited lower total and perceptive social cognition scores on the DMASC-MC than the non-PDA group and controls. In addition, they also showed lower cognitive scores compared to typical controls. Lower total scores were associated with lower scores on Wechsler intelligence subtests information and matrix reasoning. Taking this into account, the PDA group still had lower social cognition scores. There were no associations of antipsychotic medication dosages, positive or negative symptoms with social cognition scores. Higher antipsychotic dosage at the time of DMASC-MC testing and social cognition scores predicted a past history of PDA. Conclusions We conclude that impaired social cognition, particularly perceptive social cognition, is associated with PDA in individuals with PSD.

Skill learning induces changes in estimates of gray matter volume (GMV) in the human brain, commonly detectable with magnetic resonance imaging (MRI). Rapid changes in GMV estimates while executing tasks may however confound between- and within-subject differences. Fluctuations in arterial blood flow are proposed to underlie this apparent task-related tissue plasticity. To test this hypothesis, we acquired multiple repetitions of structural T1-weighted and functional blood-oxygen level-dependent (BOLD) MRI measurements from 51 subjects performing a finger-tapping task (FTT; á 2 min) repeatedly for 30–60 min. Estimated GMV was decreased in motor regions during FTT compared with rest. Motor-related BOLD signal changes did not overlap nor correlate with GMV changes. Nearly simultaneous BOLD signals cannot fully explain task-induced changes in T1-weighted images. These sensitive and behavior-related GMV changes pose serious questions to reproducibility across studies, and morphological investigations during skill learning can also open new avenues on how to study rapid brain plasticity.

Measuring brain morphology with non-invasive structural magnetic resonance imaging is common practice, and can be used to investigate neuroplasticity. Brain morphology changes have been reported over the course of weeks, days, and hours in both animals and humans. If such short-term changes occur even faster, rapid morphological changes while being scanned could have important implications. In a randomized within-subject study on 47 healthy individuals, two high-resolution T1-weighted anatomical images were acquired (á 263 s) per individual. The images were acquired during passive viewing of pictures or a fixation cross. Two common pipelines for analyzing brain images were used: voxel-based morphometry on gray matter (GM) volume and surface-based cortical thickness. We found that the measures of both GM volume and cortical thickness showed increases in the visual cortex while viewing pictures relative to a fixation cross. The increase was distributed across the two hemispheres and significant at a corrected level. Thus, brain morphology enlargements were detected in less than 263 s. Neuroplasticity is a far more dynamic process than previously shown, suggesting that individuals’ current mental state affects indices of brain morphology. This needs to be taken into account in future morphology studies and in everyday clinical practice.

In everyday life throughout the life span, people frequently evaluate faces to obtain information crucial for social interactions. We investigated age-related differences in judgments of a wide range of social attributes based on facial appearance. Seventy-one younger and 60 older participants rated 196 computer-generated faces that systematically varied in facial features such as shape and reflectance to convey different intensity levels of seven social attributes (i.e., attractiveness, competence, dominance, extraversion, likeability, threat, and trustworthiness). Older compared to younger participants consistently gave higher attractiveness ratings to faces representing both high and low levels of attractiveness. Older participants were also less sensitive to the likeability of faces and tended to evaluate faces representing low likeability as more likable. The age groups did, however, not differ substantially in their evaluations of the other social attributes. Results are in line with previous research showing that aging is associated with preference toward positive and away from negative information and extend this positivity effect to social perception of faces. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Aging is associated with increased difficulty in facial emotion identification, possibly due to age-related network change. The neuropeptide oxytocin (OT) facilitates emotion identification, but this is understudied in aging. To determine the effects of OT on dynamic facial emotion identification across adulthood, 46 young and 48 older participants self-administered intranasal OT or a placebo in a randomized, double-blind procedure. Older participants were slower and less accurate in identifying emotions. Although there was no behavioral treatment effect, partial least squares analysis supported treatment effects on brain patterns during emotion identification that varied by age and emotion. For young participants, OT altered the processing of sadness and happiness, whereas for older participants, OT only affected the processing of sadness (15.3% covariance, p = 0.004). Furthermore, seed partial least squares analysis showed that older participants in the OT group recruited a large-scale amygdalar network that was positively correlated for anger, fear, and happiness, whereas older participants in the placebo group recruited a smaller, negatively correlated network (7% covariance, p = 0.002). Advancing the literature, these findings show that OT alters brain activity and amygdalar connectivity by age and emotion.

Individuals vary in emotion recognition ability (ERA), but the causes and correlates of this variability are not well understood. Previous studies have largely focused on unimodal facial or vocal expressions and a small number of emotion categories, which may not reflect how emotions are expressed in everyday interactions. We investigated individual differences in ERA using a brief test containing dynamic multimodal (facial and vocal) expressions of 5 positive and 7 negative emotions (the ERAM test). Study 1 (N = 593) showed that ERA was positively correlated with emotional understanding, empathy, and openness, and negatively correlated with alexithymia. Women also had higher ERA than men. Study 2 was conducted online and replicated the recognition rates from Study 1 (which was conducted in lab) in a different sample (N = 106). Study 2 also showed that participants who had higher ERA were more accurate in their meta-cognitive judgments about their own accuracy. Recognition rates for visual, auditory, and audio-visual expressions were substantially correlated in both studies. Results provide further clues about the underlying structure of ERA and its links to broader affective processes. The ERAM test can be used for both lab and online research, and is freely available for academic research.

BACKGROUND: Biomarkers of psychiatric treatment response remain elusive. Functional magnetic resonance imaging (fMRI) has shown promise, but low reliability has limited the utility of typical fMRI measures (e.g., average brain signal) as harbingers of treatment success. Notably, although historically considered a source of 9noise9, temporal brain signal variability continues to gain momentum as a sensitive and reliable indicator of individual differences in neural efficacy, yet has not been examined in relation to psychiatric treatment outcomes. METHODS: Forty-five patients with social anxiety disorder were scanned twice (11 weeks apart) using simple task-based and resting-state fMRI to capture moment-to-moment neural variability. After fMRI test-retest, patients underwent a 9-week cognitive-behavioral therapy. Multivariate modeling and reliability-based cross-validation were utilized to perform brain-based prediction of treatment outcomes. RESULTS: Task-based brain signal variability was the strongest contributor in a treatment outcome prediction model (total r[ACTUAL,PREDICTED]=.77) - outperforming self-reports, resting-state neural variability, and standard mean-based measures of neural activity. Notably, task-based brain signal variability showed excellent test-retest reliability (intraclass correlation coefficient=.80), even with a task length less than 3 minutes long. CONCLUSIONS: Rather than a source of undesirable 9noise9, moment-to-moment fMRI signal variability may instead serve as a highly reliable and efficient prognostic indicator of clinical outcome.

To investigate the impact of adult age on the brain functional connectivity, whole-brain resting-state functional magnetic resonance imaging (R-fMRI) data were acquired on a 3T clinical MRI scanner in a cohort of 227, right-handed, native Swedish-speaking, healthy adult volunteers (N=227, aged 18-74 years old, male/female=99/128). The dataset is mainly consisted of a younger (18-30 years old n=124, males/females=51/73) and elderly adult (n=76, 60-76 years old, males/females=35/41) subgroups. The dataset was analyzed using a new data-driven analysis (QDA) framework. With QDA two types of threshold-free voxel-wise resting-state functional connectivity (RFC) metrics were derived: the connectivity strength index (CSI) and connectivity density index (CDI), which can be utilized to assess the brain changes in functional connectivity associated with adult age. The dataset can also be useful as a reference to identify abnormal changes in brain functional connectivity resulted from neurodegenerative or neuropsychiatric disorders.

PurposeThe objective of this study is to introduce a new quantitative data-driven analysis (QDA) framework for the analysis of resting-state fMRI (R-fMRI) and use it to investigate the effect of adult age on resting-state functional connectivity (RFC).MethodsWhole-brain R-fMRI measurements were conducted on a 3T clinical MRI scanner in 227 healthy adult volunteers (N=227, aged 18-74 years old, male/female=99/128). With the proposed QDA framework we derived two types of voxel-wise RFC metrics: the connectivity strength index (CSI) and connectivity density index (CDI) utilizing the convolutions of the cross-correlation (CC) histogram with different kernels. Furthermore, we assessed the negative and positive portions of these metrics separately.ResultsWith the QDA framework we found age-related declines of RFC metrics in the superior and middle frontal gyrus (MFG), posterior cingulate cortex (PCC), right insula and inferior parietal lobule (IPL) of the default mode network (DMN), which resembles previously reported results using other types of RFC data processing methods. Importantly, our new findings complement previously undocumented results in the following aspects: 1) the PCC and right insula are anti-correlated and tend to manifest simultaneously declines of both the negative and positive connectivity strength with subjects’ age; 2) separate assessment of the negative and positive RFC metrics provides enhanced sensitivity to the aging effect; 3) the sensorimotor network depicts enhanced negative connectivity strength with the adult age.ConclusionThe proposed QDA framework can produce threshold-free, voxel-wise analysis of R-fMRI data the RFC metrics. The detected adult age effect is largely consistent with previously reported studies using different R-fMRI analysis approaches. Moreover, the separate assessment of the negative and positive contributions to the RFC metrics can enhance the RFC sensitivity and clarify some of the mixed results in the literature regarding to the DMN and sensorimotor network involvement in adult aging.HighlightsA quantitative data-driven analysis (QDA) framework was proposed to analysis resting-state fMRI data.Threshold-free resting-state functional connectivity (RFC) metrics were derived to assess brain changes with adult age.Separate assessment of the positive and negative correlations improve sensitivity of the RFC metrics.The posterior cingulate and right insula cortices are anti-correlated and tend to manifest declines in both the negative and positive connectivity strength with adult age.Negative connectivity strength enhances with adult age in sensorimotor network.

Age-related differences in emotion recognition have predominantly been investigated using static pictures of facial expressions, and positive emotions beyond happiness have rarely been included. The current study instead used dynamic facial and vocal stimuli, and included a wider than usual range of positive emotions. In Task 1, younger and older adults were tested for their abilities to recognize 12 emotions from brief video recordings presented in visual, auditory, and multimodal blocks. Task 2 assessed recognition of 18 emotions conveyed by non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Results from both tasks showed that younger adults had significantly higher overall recognition rates than older adults. In Task 1, significant group differences (younger > older) were only observed for the auditory block (across all emotions), and for expressions of anger, irritation, and relief (across all presentation blocks). In Task 2, significant group differences were observed for 6 out of 9 positive, and 8 out of 9 negative emotions. Overall, results indicate that recognition of both positive and negative emotions show age-related differences. This suggests that the age-related positivity effect in emotion recognition may become less evident when dynamic emotional stimuli are used and happiness is not the only positive emotion under study.

BACKGROUND Biomarkers of psychiatric treatment response remain elusive. Functional magnetic resonance imaging (fMRI) has shown promise, but low reliability has limited the utility of typical fMRI measures (e.g., average brain signal) as harbingers of treatment success. Notably, although historically considered a source of “noise,” temporal brain signal variability continues to gain momentum as a sensitive and reliable indicator of individual differences in neural efficacy, yet has not been examined in relation to psychiatric treatment outcomes. METHODS Forty-five patients with social anxiety disorder were scanned twice (11 weeks apart) using simple task-based and resting-state fMRI to capture moment-to-moment neural variability. After fMRI test-retest, patients underwent a 9-week cognitive-behavioral therapy. Multivariate modeling and reliability-based cross-validation were utilized to perform brain-based prediction of treatment outcomes. RESULTS Task-based brain signal variability was the strongest contributor in a treatment outcome prediction model (total rACTUAL,PREDICTED=.77) - outperforming self-reports, resting-state neural variability, and standard mean-based measures of neural activity. Notably, task-based brain signal variability showed excellent test-retest reliability (intraclass correlation coefficient=.80), even with a task length less than 3 minutes long. CONCLUSIONS Rather than a source of undesirable “noise”, moment-to-moment fMRI signal variability may instead serve as a highly reliable and efficient prognostic indicator of clinical outcome.

How do valenced odors affect the perception and evaluation of facial expressions? We reviewed 25 studies published from 1989 to 2020 on cross-modal behavioral effects of odors on the perception of faces. The results indicate that odors may influence facial evaluations and classifications in several ways. Faces are rated as more arousing during simultaneous odor exposure, and the rated valence of faces is affected in the direction of the odor valence. For facial classification tasks, in general, valenced odors, whether pleasant or unpleasant, decrease facial emotion classification speed. The evidence for valence congruency effects was inconsistent. Some studies found that exposure to a valenced odor facilitates the processing of a similarly valenced facial expression. The results for facial evaluation were mirrored in classical conditioning studies, as faces conditioned with valenced odors were rated in the direction of the odor valence. However, the evidence of odor effects was inconsistent when the task was to classify faces. Furthermore, using a z-curve analysis, we found clear evidence for publication bias. Our recommendations for future research include greater consideration of individual differences in sensation and cognition, individual differences (e.g., differences in odor sensitivity related to age, gender, or culture), establishing standardized experimental assessments and stimuli, larger study samples, and embracing open research practices.

Sleep deprivation is proposed to inhibit top-down-control in emotion processing, but it is unclear whether sleep deprivation affects emotional mimicry and contagion. Here, we aimed to investigate effects of partial sleep deprivation on emotional contagion and mimicry in young and older humans. Participants underwent partial sleep deprivation (3 h sleep opportunity at the end of night), crossed-over with a full sleep condition in a balanced order, followed by a functional magnetic resonance imaging and electromyography (EMG) experiment with viewing of emotional and neutral faces and ratings of emotional responses. The final sample for main analyses was n = 69 (n = 36 aged 20–30 years, n = 33 aged 65–75 years). Partial sleep deprivation caused decreased activation in fusiform gyri for angry faces and decreased ratings of happiness for all stimuli, but no significant effect on the amygdala. Older participants reported more anger compared to younger participants, but no age differences were seen in brain responses to emotional faces or sensitivity to partial sleep deprivation. No effect of the sleep manipulation was seen on EMG. In conclusion, emotional contagion, but not mimicry, was affected by sleep deprivation. Our results are consistent with the previously reported increased negativity bias after insufficient sleep.The Stockholm sleepy brain study: effects of sleep deprivation on cognitive and emotional processing in young and old. https://clinicaltrials.gov/ct2/show/NCT02000076.

Background Subjectively experienced sleepiness is a problem in society, possibly linked with gray matter (GM) volume. Given a different sleep pattern, aging may affect such associations, possibly due to shrinking brain volume. Purpose The purpose of the present study was to investigate the association between subjectively rated sleepiness and GM volume in thalamus, insula, hippocampus, and orbitofrontal cortex of young and older adults, after a normal night’s sleep. Methods Eighty-four healthy individuals participated (46 aged 20–30 years, and 38 aged 65–75 years). Morphological brain data were collected in a 3T magnetic resonance imaging (MRI) scanner. Sleepiness was rated multiple times during the imaging sessions. Results In older, relative to younger, adults, clusters within bilateral mid-anterior insular cortex and right thalamus were negatively associated with sleepiness. Adjustment for the immediately preceding total sleep time eliminated the significant associations. Conclusion Self-rated momentary sleepiness in a monotonous situation appears to be negatively associated with GM volume in clusters within both thalamus and insula in older individuals, and total sleep time seems to play a role in this association. Possibly, this suggests that larger GM volume in these clusters may be protective against sleepiness in older individuals. This notion needs confirmation in further studies.

Facial recognition ability declines in adult aging, but the neural basis for this decline remains unknown. Cortical areas involved in face recognition exhibit lower dopamine (DA) receptor availability and lower blood-oxygen-level-dependent (BOLD) signal during task performance with advancing adult age. We hypothesized that changes in the relationship between these two neural systems are related to age differences in face-recognition ability. To test this hypothesis, we leveraged positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to measure D1 receptor binding potential (BPND) and BOLD signal during face-recognition performance. Twenty younger and 20 older participants performed a face-recognition task during fMRI scanning. Face recognition accuracy was lower in older than in younger adults, as were D1 BPND and BOLD signal across the brain. Using linear regression, significant relationships between DA and BOLD were found in both age-groups in face-processing regions. Interestingly, although the relationship was positive in younger adults, it was negative in older adults (i.e., as D1 BPND decreased, BOLD signal increased). Ratios of BOLD:D1 BPND were calculated and relationships to face-recognition performance were tested. Multiple linear regression revealed a significant Group × BOLD:D1 BPND Ratio interaction. These results suggest that, in the healthy system, synchrony between neurotransmitter (DA) and hemodynamic (BOLD) systems optimizes the level of BOLD activation evoked for a given DA input (i.e., the gain parameter of the DA input-neural activation function), facilitating task performance. In the aged system, however, desynchronization between these brain systems would reduce the gain parameter of this function, adversely impacting task performance and contributing to reduced face recognition in older adults.

Social anxiety disorder (SAD) is characterized by exaggerated amygdala reactivity in response to symptom provocation, but it is unclear if such hyper-reactivity is elicited by disorder-specific challenges only or characterizes reactions to aversive stimuli in general. Here, using functional magnetic resonance imaging in 14 patients with SAD, as compared to 12 healthy controls, we found that amygdala hyper-reactivity is confined to disorder-relevant social stimulation. SAD patients displayed increased amygdala reactivity to fearful as compared to neutral facial pictures, but not in response to generally aversive but mainly non-social stimulation when compared to neutral pictorial stimuli taken from the International Affective Picture System. The increased amygdala reactivity was not mediated by an altered prefrontal inhibition among SAD patients as compared to controls, suggesting increased bottom-up processes rather than attenuated top-down control. In conclusion, the enhanced amygdala reactivity in SAD seems specific to socially relevant stimuli rather than aversive stimuli in general.

OBJECTIVE The literature on emotional processing in Parkinson's disease (PD) patients shows mixed results. This may be because of various methodological and/or patient-related differences, such as failing to adjust for cognitive functioning, depression, and/or mood. METHOD In the current study, we tested PD patients and healthy controls (HCs) using emotional stimuli across a variety of tasks, including visual search, short-term memory (STM), categorical perception, and emotional stimulus rating. The PD and HC groups were matched on cognitive ability, depression, and mood. We also explored possible relationships between task results and antiparkinsonian treatment effects, as measured by levodopa equivalent dosages (LED), in the PD group. RESULTS The results show that PD patients use a larger emotional range compared with HCs when reporting their impression of emotional faces on rated emotional valence, arousal, and potency. The results also show that dopaminergic therapy was correlated with stimulus rating results such that PD patients with higher LED scores rated negative faces as less arousing, less negative, and less powerful. Finally, results also show that PD patients display a general slowing effect in the visual search tasks compared with HCs, indicating overall slowed responses. There were no group differences observed in the STM or categorical perception tasks. CONCLUSIONS Our results indicate a relationship between emotional responses, PD, and dopaminergic therapy, in which PD per se is associated with stronger emotional responses, whereas LED levels are negatively correlated with the strength of emotional responses. (PsycINFO Database Record

Face attractiveness can influence memory for previously seen faces. This effect has been shown to differ for young and older perceivers. Two parallel studies examined the moderation of both the age of the face and the age of the perceiver on the relationship between facial attractiveness and face memory. Study 1 comprised 29 young and 31 older participants; Study 2 comprised 25 young and 24 older participants. In both studies, participants completed an incidental face encoding and a surprise old/new recognition test with young and older faces that varied in face attractiveness. Face attractiveness affected memory for young but not older faces. In addition, young but not older perceivers showed a linear effect of facial attractiveness on memory for young faces, while both young and older perceivers showed a quadratic effect on memory for young faces. These findings extend previous work by demonstrating that the effect of facial attractiveness on face memory is a function of both the age of the perceiver and the age of the face. Factors that could account for such moderations of face and perceiver age on the associations between face attractiveness and face memory are discussed (e.g., age differences in social goals and face similarity/distinctiveness).

Social interactions require decoding of subtle rapidly changing emotional cues in others to facilitate socially appropriate behaviour. It is possible that impairments in the ability to detect and decode these signals may increase the risk for aggression. Therefore, we examined violent offenders with schizophrenia spectrum disorders (SSD) and compared these with healthy controls on a computerized paradigm of briefly presented double masked faces exhibiting 7 basic emotions. Our hypotheses were that impaired semantic understanding of emotion words and low cognitive ability would yield lowest emotion recognition. SSD exhibited lower accuracy of emotion perception than controls (46.1% compared with 64.5%, p = 0.026), even when considering the unbiased hit rate (22.4% compared with 43%, Z = 2.62, p

The neuropeptide oxytocin plays a role in social cognition and affective processing. The neural processes underlying these effects are not well understood. Modulation of connectivity strength between subcortical and cortical regions has been suggested as one possible mechanism. The current study investigated effects of intranasal oxytocin administration on resting-state functional connectivity between amygdala and medial prefrontal cortex (mPFC), as two central regions involved in social-cognitive and affective processing. Going beyond previous work that largely examined young male participants, our study comprised young and older men and women to identify age and sex variations in oxytocin's central processes. This approach was based on known hormonal differences among these groups and emerging evidence of sex differences in oxytocin's effects on amygdala reactivity and age-by-sex-modulated effects of oxytocin in affective processing. In a double-blind design, 79 participants were randomly assigned to self-administer either intranasal oxytocin or placebo before undergoing resting-state functional magnetic resonance imaging. Using a targeted region-to-region approach, resting-state functional connectivity strength between bilateral amygdala and mPFC was examined. Participants in the oxytocin compared to the placebo group and men compared to women had overall greater amygdala mPFC connectivity strength at rest. These main effects were qualified by a significant three-way interaction: while oxytocin compared to placebo administration increased resting-state amygdala mPFC connectivity for young women, oxytocin did not significantly modulate connectivity in the other age-by-sex subgroups. This study provides novel evidence of age-by-sex differences in how oxytocin modulates resting-state brain connectivity, furthering our understanding of how oxytocin affects brain networks at rest.

Background: There is considerable inter-individual variability in the response to treatment in psychiatric patients. Tools in translational neuroscience, e.g., functional magnetic resonance imaging ...

Background: Older adults perform better in tasks which include positive stimuli, referred to as the positivity effect. However, recent research suggests that the positivity effect could be attenuated when additional challenges such as stress or cognitive demands are introduced. Moreover, it is well established that older adults are relatively resilient to many of the adverse effects of sleep deprivation. Our aim was to investigate if the positivity effect in older adults is affected by one night of total sleep deprivation using an emotional working memory task. Methods: A healthy sample of 48 older adults (60-72 years) was either sleep deprived for one night (n = 24) or had a normal night’s sleep (n = 24). They performed an emotional working memory n-back (n = 1 & 3) task containing positive, negative and neutral pictures. Results: Performance in terms of accuracy and reaction times was best for positive stimuli and worst for negative stimuli. This positivity effect was not altered by sleep deprivation. Results also showed that, despite significantly increased sleepiness, there was no effect of sleep deprivation on working memory performance. A working memory load × valence interaction on the reaction times revealed that the beneficial effect of positive stimuli was only present in the 1-back condition. Conclusion: While the positivity effect and general working memory abilities in older adults are intact after one night of sleep deprivation, increased cognitive demand attenuates the positivity effect on working memory speed.

Odors affect perception of social cues in visual environments. Although often underestimated, people use their sense of smell to guide approach or avoidance behavior in social contexts. However, underlying psychological mechanisms are not well known. Prior work suggested olfactory effects are due to increased attention or arousal, or depend on the congruency between olfactory and visual cues. Our aim was to assess how odors influence attentional processes using a dot-probe task with odor-congruent and odor-incongruent facial expressions (happy, disgusted and neutral expressions paired with pleasant odor, unpleasant odor and no-odor). In a preregistered analysis plan, we hypothesized either faster reaction times attributed to arousal from odors in general, or to faces that were emotionally congruent with the odors. We also hypothesized time-on-task effects specific to the odor compared to the control condition. Using Bayesian linear models, we found strong evidence that the faces were rated as more arousing and emotional in odor contexts. However, the dot-probe task did in fact not provide an effective cue to selective visual attention, and odors did not modulate overall attention to the faces. However, we found a time-on-task effect such that in the unpleasant odor condition, response times decreased over time, whereas in the no-odor and pleasant condition there was a slight increase in response times. We conclude that time-on-task effects is an interesting venue for odor-visual interaction research, and such effects might explain inconsistent findings in the prior research literature.

SummarySleep restriction has been proposed to cause impaired emotional processing and emotional regulation by inhibiting top-down control from prefrontal cortex to amygdala. Intentional emotional regulation after sleep restriction has however never been studied using brain imaging. We here aimed to investigate the effect of sleep restriction on emotional regulation through cognitive reappraisal. Forty-seven young (age 20-30) and 33 older (age 65-75) participants (38/23 with complete data and successful sleep intervention) performed a cognitive reappraisal task during fMRI after a night of normal sleep and after restricted sleep (3h). Emotional downregulation was associated with significantly increased activity in dorsolateral prefrontal cortex (pFWE < 0.05) and lateral orbital cortex (pFWE < 0.05) in young, but not in older subjects. Sleep restriction was associated with a decrease in self-reported regulation success to negative stimuli (p < 0.01) and a trend towards perceiving all stimuli as less negative (p = 0.07), in young participants. No effects of sleep restriction on brain activity nor connectivity were found in either age group. In conclusion, our data do not support the idea of a prefrontal-amygdala disconnect after sleep restriction, and neural mechanisms underlying behavioural effects on emotional regulation after insufficient sleep require further investigation.

Brain morphology change over the course of weeks, days, and hours, and can be detected by non-invasive structural magnetic resonance imaging. Rapid morphological changes at scanning has yet not been investigated. In a randomized within-group study, high-resolution anatomical images were acquired during passive viewing of pictures or a fixation cross. Forty-seven individuals gray matter volume and cortical thickness were investigated, and both measures increased in the visual cortex while viewing pictures relative to a fixation cross. Thus, brain morphology enlargements were detected in less than 263 seconds. Neuroplasticity is a far more dynamic process than previously shown, suggesting that individuals’ current mental state affects indices of brain morphology. This needs to be taken into account in future morphology studies and in everyday clinical practice.

Intranasal oxytocin (OT) has previously been found to increase spirituality, an effect moderated by OT-related genotypes. This pre-registered study sought to conceptually replicate and extend those findings. Using a single dose of intranasal OT vs placebo (PL), we investigated experimental treatment effects, and moderation by OT-related genotypes on spirituality, mystical experiences, and the sensed presence of a sentient being. A more exploratory aim was to test for interactions between treatment and the personality disposition absorption on these spirituality-related outcomes. A priming plus sensory deprivation procedure that has facilitated spiritual experiences in previous studies was used. The sample (N = 116) contained both sexes and was drawn from a relatively secular context. Results failed to conceptually replicate both the main effects of treatment and the treatment by genotype interactions on spirituality. Similarly, there were no such effects on mystical experiences or sensed presence. However, the data suggested an interaction between treatment and absorption. Relative to PL, OT seemed to enhance spiritual experiences in participants scoring low in absorption and dampen spirituality in participants scoring high in absorption.