Electro/magnetoencephalographic signatures of human brain insulin resistance

Human insulin action influences eating behavior, peripheral metabolism and cognition. Detailed insights into the neuronal processes related to human brain insulin action can be obtained by direct measures of neuronal activity with electroencephalography and magnetoencephalography. Results of recent studies show that spontaneous, task and stimulus related neuronal activity is modulated by insulin and that several factors like increased body weight and body composition can result in brain insulin resistance. Recent technological advances even allow the investigation of human brain functions in utero in relation to the metabolic status of the mother and indicate an effect of the mother’s insulin sensitivity on the brain function of the fetus. In conclusion, studies based on direct neuronal measurements may help to determine the developmental trajectory related to insulin action and resistance

Changes in event-related brain responses and habituation during child development - A systematic literature review

Abstract Objective This systematic review highlights the influence of developmental changes of the central nervous system on habituation assessment during child development. Therefore, studies on age dependant changes in event-related brain responses as well as studies on behavioural and neurophysiological habituation during child development are compiled and discussed. Methods Two PubMed searches with terms “(development evoked brain response (fetus OR neonate OR children) (electroencephalography OR magnetoencephalography))” and with terms “(psychology habituation (fetal OR neonate OR children) (human brain)” were performed to identify studies on developmental changes in event-related brain responses as well as habituation studies during child development. Results Both search results showed a wide diversity of subjects’ ages, stimulation protocols and examined behaviour or components of event-related brain responses as well as a demand for more longitudinal study designs. Conclusions A conclusive statement about clear developmental trends in event-related brain responses or in neurophysiological habituation studies is difficult to draw. Future studies should implement longitudinal designs, combination of behavioural and neurophysiological habituation measurement and more complex habituation paradigms to assess several habituation criteria

Materner Metabolismus und fetale Entwicklung.

Background Human development is already influenced by external factors in utero. During this vulnerable period, developmental origins of health and disease emerge, with maternal metabolism playing a central role. Scope of review In this article, studies that examine the influence of maternal parameters related to metabolism on fetal development of the central and autonomous nervous system are summarized. Conclusion Maternal factors during pregnancy (weight gain, insulin sensitivity, gestational diabetes) and before pregnancy (body mass index, preconceptional diabetes) can influence a number of fetal factors, like postprandial brain activity in response to stimulation, spontaneous brain activity, fetal heart rate, and fetal postprandial heart rate variability

Evaluating Complexity of Fetal MEG Signals A Comparison of Different Metrics and Their Applicability

International audienceIn this work, we aim to investigate whether information based metrics of neural activity are a useful tool for the quantification of consciousness before and shortly after birth. Neural activity is measured using fetal magnetoencephalography (fMEG) in human fetuses and neonates. Based on recent theories on consciousness, information-based metrics are established to measure brain complexity and to assess different levels of consciousness. Different metrics (measures of entropy, compressibility and fractality) are, thus, explored in a reference population and their usability is evaluated. For comparative analysis, two fMEG channels were selected one where brain activity was previously detected and one at least 15 cm away, that represented a control channel. The usability of each metric was evaluated and results from the brain and control channel were compared. Concerning the ease of use with fMEG data, Lempel-Ziv-Complexity (LZC) was evaluated as best, as it is unequivocal and needs low computational effort. The fractality measures have a high number of parameters that need to be adjusted prior to analysis and therefore forfeit comparability, while entropy measures require a higher computational effort and more parameters to adjust compared to LZC. Comparison of a channel with brain activity and a control channel in neonatal recordings showed significant differences in most complexity metrics. This clear difference can be seen as proof of concept for the usability of complexity metrics in fMEG. For fetal data, this comparison produced less clear results which can be related to leftover maternal signals included in the control channel. Further work is necessary to conclusively interpret results from the analysis of fetal recordings. Yet this study shows that complexity metrics can be used for fMEG data on early consciousness and the evaluation gives a guidance for future work. The inconsistency of results from different metrics highlights the challenges of working with complexity metrics as neural correlates of consciousness, as well as the caution one should apply to interpret them

Acute relaxation during pregnancy leads to a reduction in maternal electrodermal activity, changes in cardiovascular activity and subjective stress levels depending on the week of gestation.

Background: Prenatal maternal stress can have adverse effects on birth outcomes and fetal development. Relaxation techniques have been examined as one potential countermeasure. This study investigates different relaxation techniques and their effect on mood and physiological stress levels in pregnant women. Methods: 36 pregnant women (30 to 40 weeks of gestation) were randomly assigned to one of three groups: music, guided imagery or resting. Dependent measures included self-report questionnaires, subjective ratings of stress levels as well as physiological measures, i.e. cardiovascular and electrodermal activity. Results: All three forms of relaxation led to reduced maternal stress: decreased heart rate and decreased skin conductance levels. Based on heart rate, skin conductance level and stress ratings there were no significant differences between relaxation interventions. Subjective post-intervention stress ratings indicated that more relaxation occured after intervention in earlier gestation than in late gestation. Conclusion: Independent of relaxation technique, a 20-minute period of acute relaxation can reduce maternal stress. Notably, women earlier in pregnancy reported to be more relaxed after the intervention than women later in gestation. Hence, gestational age can influence perceived stress levels and should be considered when evaluating relaxation or stress management interventions during pregnancy