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Major depressive disorder has a large impact on patients and society and is projected to be the second greatest global burden of disease by 2020. The brain-derived neurotrophic factor (BDNF) gene is considered to be one of the important factors in the etiology of major depressive disorder. In a recent study, alpha power was found to mediate between BDNF Met and subclinical depressed mood. The current study looked at a population of patients with major depressive disorder (N = 107) to examine the association between the BDNF Val66Met polymorphism, resting state EEG alpha power, and depression severity. For this purpose, repeated-measures analysis of variance, partial correlation, and multiple linear models were used. Results indicated a negative association between parietal-occipital alpha power in the eyes open resting state and depression severity. In addition, Met/Met patients showed lower global absolute alpha power in the eyes closed condition compared with Val-carriers. These findings are in accordance with the previously uncovered pathway between BDNF Val66Met, resting state EEG alpha power, and depression severity. Additional research is needed for the clarification of this tentative pathway and its implication in personalized treatment of major depressive disorder.

Objective: We investigated the association between mean corpuscular volume (MCV), carbohydrate-deficient transferrin (CDT), and gamma-glutamyl transferase (GGT) levels and gray and white brain matter in male drinkers to find out which if any of these biomarkers of alcohol consumption is indicative for alcohol-related differences in brain volume., Method: Plasma levels of CDT, GGT, and MCV and magnetic resonance imaging-determined brain gray and white matter volumes were assessed in 55 male drinkers. Current alcohol intake and lifetime alcohol intake were determined by self-report measures. The relationship between MCV, CDT, and GGT and brain volumes was explored using multiple linear regression analyses., Results: There was a significant negative relationship between plasma GGT and MCV levels and gray matter volumes. Middle-aged male drinkers with highly elevated GGT and MCV levels (twice the standard deviation above the mean) have 4-12% less parietal and occipital gray matter than males with average GGT and MCV levels. There was no association between CDT levels and brain gray or white matter., Conclusions: Elevated GGT and MCV levels may be indicative of alcohol-related gray-matter decline in male drinkers. The link with GGT may reflect that elevated GGT levels are a sign of increased oxidative stress. The link with MCV levels may reflect a decreased oxygen transport to the brain., (Copyright © 2012 John Wiley & Sons, Ltd.)

The acquisition of a conditioned fear response is adaptive, as it enables the organism to appropriately respond to predictors of aversive events. Consequently, the absence of predictive cues can be used as a signal for safety. We aimed to study whether deficient fear conditioning might lead to maladaptive fear. Following previous work, we predicted that failure to learn the CS-US association would result in higher contextual fear, and that participants who failed to learn would tend to exhibit higher trait anxiety. Conditioning took place in a virtual environment with two contexts. In one of the two contexts, offset of a CS (light) was associated with a shock. Each participant visited two places (a house and an apartment) in each of 12 blocks. In one of these places shocks were administered at the offset of an 8-s period of lights on (CS). The results showed that half of the participants demonstrated differential shock expectancy between situations in the shock context in which the CS was present versus absent. This indicates that these participants learned the contingencies between the shocks and both the context and the light CS. In contrast, the other half of the participants learned only the association with the context. As predicted, learning the CS-US contingency resulted in reduced self-reported fear in the absence of the CS in the danger context compared to the presence of the CS. On the other hand, participants who failed to learn the association displayed a sustained aversive state throughout the duration of the danger context. Skin conductance measures confirmed this pattern of results. Fear-potentiated startle during the threat context compared to the safe context was significant in both groups, while startle was only potentiated during the CS in the threat context in the group that learned the CS association (trend-level significant). Finally, scores on Spielberger's self-report scale of trait anxiety tended to be higher in the group of participants who did not learn the CS-shock association in the danger context compared to participants who did. In conclusion, these results confirm higher contextual fear in participants who did not acquire a conditioned response to the cue in comparison to participants who did. Also, virtual reality contexts provide a useful tool for the study of context conditioning.