Sex-dependent dissociation between emotional appraisal and memory: a large-scale behavioral and fMRI study

Extensive evidence indicates that women outperform men in episodic memory tasks. Furthermore, women are known to evaluate emotional stimuli as more arousing than men. Because emotional arousal typically increases episodic memory formation, the females' memory advantage might be more pronounced for emotionally arousing information than for neutral information. Here, we report behavioral data from 3398 subjects, who performed picture rating and memory tasks, and corresponding fMRI data from up to 696 subjects. We were interested in the interaction between sex and valence category on emotional appraisal, memory performances, and fMRI activity. The behavioral results showed that females evaluate in particular negative (p < 10(-16)) and positive (p = 2 × 10(-4)), but not neutral pictures, as emotionally more arousing (pinteraction < 10(-16)) than males. However, in the free recall females outperformed males not only in positive (p < 10(-16)) and negative (p < 5 × 10(-5)), but also in neutral picture recall (p < 3.4 × 10(-8)), with a particular advantage for positive pictures (pinteraction < 4.4 × 10(-10)). Importantly, females' memory advantage during free recall was absent in a recognition setting. We identified activation differences in fMRI, which corresponded to the females' stronger appraisal of especially negative pictures, but no activation differences that reflected the interaction effect in the free recall memory task. In conclusion, females' valence-category-specific memory advantage is only observed in a free recall, but not a recognition setting and does not depend on females' higher emotional appraisal

Common epigenetic variation in a European population of mentally healthy young adults

DNA methylation represents an important link between structural genetic variation and complex phenotypes. The study of genome-wide CpG methylation and its relation to traits relevant to psychiatry has become increasingly important. Here, we analyzed quality metrics of 394,043 CpG sites in two samples of 568 and 319 mentally healthy young adults. For 25% of all CpGs we observed medium to large common epigenetic variation. These CpGs were overrepresented in open sea and shore regions, as well as in intergenic regions. They also showed a strong enrichment of significant hits in association analyses. Furthermore, a significant proportion of common DNA methylation is at least partially genetically driven and thus may be observed similarly across tissues. These findings could be of particular relevance for studies of complex neuropsychiatric traits, which often rely on proxy tissues

Lunar cycle effects on sleep and the file drawer problem

Contains fulltext : 135956.pdf (Publisher’s version ) (Open Access)Popular beliefs about the influence of the full moon on humans exist, although no solid evidence has so far confirmed these ideas [1]. Cajochen et al.[2] recently presented fascinating data on lunar cycle effects on human sleep. However, in a re-analysis of sleep electroencephalography (EEG) data in three large samples, we were unable to replicate their findings. In addition, we identified further mostly unpublished null findings, suggesting that the conflicting results might be an example of a publication bias (i.e., the file drawer problem).2 p

Hormonal and genetic modulation of memory processes in healthy humans: focus on cortisol and "HDAC5"

Individual differences in memory performance can be due to the influence of various hormones as well as genetic variations and epigenetic modifications. These complex molecular and genetic mechanisms can impact learning, memory consolidation and retrieval differentially. This thesis deals with the modulation of memory processes in healthy human subjects focusing on two viewpoints. Firstly, by addressing the influence of the stress hormone cortisol, as evidence from animal and human studies shows that cortisol can enhance memory consolidation and impair retrieval. Secondly, by analyzing genetic and epigenetic data to find a target associated with synaptic plasticity and memory formation. To investigate if stress, induced by the cold pressor test, affects memory processes, a fear-conditioning paradigm was used. The stress group showed an increase in the cortisol level and reduced retrieval of the conditioned fear memory. In a further study, we investigated if inter-individual changes in basal cortisol levels affect episodic memory. Results showed an association between stronger decreases in cortisol levels during retrieval and a better recall performance. In a large genetic study we focused on genetic polymorphisms tagging histone deacetylase 5 (HDAC5), a gene associated with synaptic plasticity and memory formation in animal models. We detected significant associations between these polymorphisms and episodic memory performance, especially for emotional information. Surprisingly, these polymorphisms were strongly associated with expression levels of a transcript in the vicinity of HDAC5. These results may have implications for the understanding of the mechanisms underlying memory formation in healthy subjects and the interpretation of genetic data. Additionally, our results may have clinical implications for different neuropsychiatric disorders, such as depression, anxiety disorders or posttraumatic stress disorder, for which learning and memory play an important role

Manual Correction of Voxel Misclassifications in Mesiotemporal Structures Does Not Alter Brain-Behavioral Results in an Episodic Memory Task

Voxel-based morphometry (VBM) is an established method for assessing grey matter volumes across the brain. The quality of magnetic resonance imaging (MRI) and the chosen data preprocessing steps can affect the outcome of VBM analyses. We recognized a lack of publicly available and commonly used protocols, which indicates that standardized and optimized preprocessing protocols are needed. This paper focuses on the time- and resource-consuming manual correction of misclassifications of grey matter voxels in cortical structures important in Alzheimer's dementia. A total of 126 individuals, including 63 patients with very early Alzheimer's disease and 63 cognitively normal participants, received thorough neuropsychological testing and 3-Tesla MRI. Automated preprocessing of T1 MPRAGE images was performed, and misclassifications of grey matter voxels were manually identified and corrected. In a second run, the manual correction step was skipped. Multiple regression analyses using DARTEL in SPM8 were then conducted with the manually corrected and uncorrected sample, respectively. Manual correction of voxel misclassifications did not have a major impact on the correlation between episodic memory performance and structural brain imaging results. We conclude that, although performing all preprocessing steps remains the gold standard, skipping manual correction of voxel misclassifications is permitted when investigating populations on the Alzheimer's disease spectrum

No Associations between Interindividual Differences in Sleep Parameters and Episodic Memory Consolidation

Sleep and memory are stable and heritable traits that strongly differ between individuals. Sleep benefits memory consolidation, and the amount of slow wave sleep, sleep spindles, and rapid eye movement sleep have been repeatedly identified as reliable predictors for the amount of declarative and/or emotional memories retrieved after a consolidation period filled with sleep. These studies typically encompass small sample sizes, increasing the probability of overestimating the real association strength. In a large sample we tested whether individual differences in sleep are predictive for individual differences in memory for emotional and neutral pictures.; Between-subject design.; Cognitive testing took place at the University of Basel, Switzerland. Sleep was recorded at participants' homes, using portable electroencephalograph-recording devices.; Nine hundred-twenty-nine healthy young participants (mean age 22.48 ± 3.60 y standard deviation).; None.; In striking contrast to our expectations as well as numerous previous findings, we did not find any significant correlations between sleep and memory consolidation for pictorial stimuli.; Our results indicate that individual differences in sleep are much less predictive for pictorial memory processes than previously assumed and suggest that previous studies using small sample sizes might have overestimated the association strength between sleep stage duration and pictorial memory performance. Future studies need to determine whether intraindividual differences rather than interindividual differences in sleep stage duration might be more predictive for the consolidation of emotional and neutral pictures during sleep

Women using hormonal contraceptives show increased valence ratings and memory performance for emotional information

Perception of emotional valence and emotional memory performance vary across the menstrual cycle. However, the consequences of altered ovarian hormone levels due to the intake of hormonal contraceptives on these emotional and cognitive processes remain to be established. In the present study, which included 2169 healthy young females, we show that hormonal contraceptives (HC) users rated emotional pictures as more emotional than HC-non-users and outperformed non-users in terms of better memory recall of emotional pictures. The observed association between HC-status and memory performance was partially mediated by the perception of emotional picture valence, indicating that increased valence ratings of emotional pictures in HC-users led to their better emotional memory performance. These findings extend the knowledge about the relation of HC-intake with emotional valence perception and emotional memory performance. Further, the findings might stimulate further research investigating the interrelation of enhanced memory for emotional events and the increased risk for anxiety-related psychiatric disorders in women.peerReviewe

Associations between Basal Cortisol Levels and Memory Retrieval in Healthy Young Individuals

Cortisol is known to affect memory processes. On the one hand, stress-induced or pharmacologically induced elevations of cortisol levels enhance memory consolidation. On the other hand, such experimentally induced elevations of cortisol levels have been shown to impair memory retrieval. However, the effects of individual differences in basal cortisol levels on memory processes remain largely unknown. Here we tested whether individual differences in cortisol levels predict picture learning and recall in a large sample. A total of 1225 healthy young women and men viewed two different sets of emotional and neutral pictures on two consecutive days. Both sets were recalled after a short delay (10 min). On Day 2, the pictures seen on Day 1 were additionally recalled, resulting in a long-delay (20 hr) recall condition. Cortisol levels were measured three times on Days 1 and 2 via saliva samples before encoding, between encoding and recall as well as after recall testing. We show that stronger decreases in cortisol levels during retrieval testing were associated with better recall performance of pictures, regardless of emotional valence of the pictures or length of the retention interval (i.e., 10 min vs. 20 hr). In contrast, average cortisol levels during retrieval were not related to picture recall. Remarkably during encoding, individual differences in average cortisol levels as well as changes in cortisol did not predict memory recall. Our results support previous findings indicating that higher cortisol levels during retrieval testing hinders recall of episodic memories and extend this view onto interindividual changes in basal cortisol levels

Influence of stress on fear memory processes in an aversive differential conditioning paradigm in humans

It is widely assumed that learning and memory processes play an important role in the pathogenesis, expression, maintenance and therapy of anxiety disorders, such as phobias or post-traumatic stress disorder (PTSD). Memory retrieval is involved in symptom expression and maintenance of these disorders, while memory extinction is believed to be the underlying mechanism of behavioral exposure therapy of anxiety disorders. There is abundant evidence that stress and stress hormones can reduce memory retrieval of emotional information, whereas they enhance memory consolidation of extinction training. In this study we aimed at investigating if stress affects these memory processes in a fear conditioning paradigm in healthy human subjects. On day 1, fear memory was acquired through a standard differential fear conditioning procedure. On day 2 (24h after fear acquisition), participants either underwent a stressful cold pressor test (CPT) or a control condition, 20min before memory retrieval testing and extinction training. Possible prolonged effects of the stress manipulation were investigated on day 3 (48h after fear acquisition), when memory retrieval and extinction were tested again. On day 2, men in the stress group showed a robust cortisol response to stress and showed lower unconditioned stimulus (US) expectancy ratings than men in the control group. This reduction in fear memory retrieval was maintained on day 3. In women, who showed a significantly smaller cortisol response to stress than men, no stress effects on fear memory retrieval were observed. No group differences were observed with respect to extinction. In conclusion, the present study provides evidence that stress can reduce memory retrieval of conditioned fear in men. Our findings may contribute to the understanding of the effects of stress and glucocorticoids on fear symptoms in anxiety disorders and suggest that such effects may be sex-specific

The NCAM1 gene set is linked to depressive symptoms and their brain structural correlates in healthy individuals

Depressive symptoms exist on a continuum, the far end of which is found in depressive disorders. Utilizing the continuous spectrum of depressive symptoms may therefore contribute to the understanding of the biological underpinnings of depression. Gene set enrichment analysis (GSEA) is an important tool for the identification of gene groups linked to complex traits, and was applied in the present study on genome-wide association study (GWAS) data of depression scores and their brain-level structural correlates in healthy young individuals. On symptom level (i.e. depression scores), robust enrichment was identified for two gene sets: NCAM1 Interactions and Collagen Formation. Depression scores were also associated with decreased fractional anisotropy (FA) - a brain white matter property - within the forceps minor and the left superior temporal longitudinal fasciculus. Within each of these tracts, mean FA value of depression score-associated voxels was used as a phenotype in a subsequent GSEA. The NCAM1 Interactions gene set was significantly enriched in these tracts. By linking the NCAM1 Interactions gene set to depression scores and their structural brain correlates in healthy participants, the current study contributes to the understanding of the molecular underpinnings of depressive symptomatology