A short-term musical training affects implicit emotion regulation only in behaviour but not in brain activity.

BACKGROUND: In everyday life, negative emotions can be implicitly regulated by positive stimuli, without any conscious cognitive engagement; however, the effects of such implicit regulation on mood and related neuro-mechanisms, remain poorly investigated in literature. Yet, improving implicit emotional regulation could reduce psychological burden and therefore be clinically relevant for treating psychiatric disorders with strong affective symptomatology. RESULTS: Music training reduced the negative emotional state elicited by negative odours. However, such change was not reflected at the brain level. CONCLUSIONS: In a context of affective rivalry a musical training enhances implicit regulatory processes. Our findings offer a first base for future studies on implicit emotion regulation in clinical populations.

In a sweet mood? Effects of experimental modulation of blood glucose levels on mood-induction during fMRI.

Glucose is the primary source of energy for the human brain. Previous literature has shown that varying blood glucose levels may have a strong impact on behaviour, subjective mood, and the intensity of the BOLD signal measured in fMRI. Therefore, blood glucose levels varying even within the normal range may interact with cognitive and emotional processing as well as BOLD signal. Here, in a placebo-controlled, double-blind crossover study on 20 healthy women, we show that overnight fasting, compared to an elevated glucose condition, influences brain activation and the affective state during mood induction. Results indicate that our brain may compensate for low glucose levels during fasting by stronger recruitment of the brain areas relevant to the task at hand. Additionally, we systematically tested the effect of prior cognitive effort on behavioural and neural patterns and found that elevated activation is only associated with maintained performance as long as no prior cognitively challenging task is administered. Prior cognitive effort leads to deteriorated performance and a further increase in emotion-associated brain activation in the pregenual anterior and posterior cingulate, the superior frontal gyrus, and the pre-SMA. These results are in line with the strength model of self-regulation. Our results corroborate the strength model of self-regulation and extend it to affect regulation processes. Additionally, our observations suggest that experimentally controlling for fasting state or glucose levels may be beneficial, especially when studying processes that involve self-regulation.

[The relevance of the TNF-alpha system in psychiatric disorders]. / Die Bedeutung des TNF-alpha-Systems für Erkrankungen des Gehirns.

Changes regarding the immune system and specifically the cytokine system, of which tumor necrosis factor-alpha (TNF-alpha) is a part, have been shown to be involved in the development of neurological and psychiatric disorders such as multiple sclerosis, Parkinson's and Alzheimer's disease, depression, schizophrenia or narcolepsy. Besides, there is evidence that the risk of stroke correlates with the serum concentrations of different cytokines. Additionally, body weight, age and neuroendocrinological mechanism have a strong influence upon plasma levels of TNF-alpha and its soluble receptors (sTNF-Rs). TNF-alpha might contribute to the pathogenesis of these diseases by an activation of the hypothalamo-pituitary-adrenocortical (HPA) axis, an activation of neuronal serotonin transporters, the stimulation of the indoleamine 2,3-dioxygenase which leads to tryptophan depletion, by immunologically mediated destruction of neurons, or neurotoxic release of glutamate. Psychotropic drugs influence the TNF-alpha system, too. During psychopharmacological treatment of schizophrenia, some antipsychotics might act on neurotransmitter metabolism via inducing the proinflammatory cytokine system. Hopefully, these hypotheses may lead to new therapeutical strategies for psychiatric patients in the near future.

Prolonged fasting impairs neural reactivity to visual stimulation.

Previous literature has shown that hypoglycemia influences the intensity of the BOLD signal. A similar but smaller effect may also be elicited by low normal blood glucose levels in healthy individuals. This may not only confound the BOLD signal measured in fMRI, but also more generally interact with cognitive processing, and thus indirectly influence fMRI results. Here we show in a placebo-controlled, crossover, double-blind study on 40 healthy subjects, that overnight fasting and low normal levels of glucose contrasted to an activated, elevated glucose condition have an impact on brain activation during basal visual stimulation. Additionally, functional connectivity of the visual cortex shows a strengthened association with higher-order attention-related brain areas in an elevated blood glucose condition compared to the fasting condition. In a fasting state visual brain areas show stronger coupling to the inferior temporal gyrus. Results demonstrate that prolonged overnight fasting leads to a diminished BOLD signal in higher-order occipital processing areas when compared to an elevated blood glucose condition. Additionally, functional connectivity patterns underscore the modulatory influence of fasting on visual brain networks. Patterns of brain activation and functional connectivity associated with a broad range of attentional processes are affected by maturation and aging and associated with psychiatric disease and intoxication. Thus, we conclude that prolonged fasting may decrease fMRI design sensitivity in any task involving attentional processes when fasting status or blood glucose is not controlled.