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The sensorimotor cortical system undergoes structural and functional changes across its lifespan. Some of these changes are physiological and parallel the normal aging process, while others might represent pathophysiological mechanisms underlying neurodegenerative disorders. In the last years, the study of possible age-related modifications in brain sensorimotor functional characteristics has been the focus of several research projects. Here we have used the transcranial magnetic stimulation (TMS)-electroencephalography (EEG) navigated co-registration to investigate the influence of physiological aging on the excitability and connectivity of the human sensorimotor cortical system. To this end, we compared the TMS-evoked EEG potentials (TEPs) collected after stimulating the dominant primary motor cortex (M1) in healthy young subjects (mean age 24.5years) with those collected in healthy older adults (mean age 67.6years). We have shown that, after stimulation of the left motor cortex, TEPs are significantly affected by physiological aging. This phenomenon has a clear spatio-temporal specificity and we speculate that normal aging per se leads to some changes in the excitability of specific cortical neural assemblies whereas other alterations could reflect compensatory mechanisms to such changes., (Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.)

It was recently demonstrated that the characteristics of EEG rhythms preceding a transcranial magnetic stimulation (TMS) of the motor cortex (M1) influence the motor-evoked potential (MEP) amplitude with a peculiar pattern, thus reflecting the M1 functional state. As physiological aging is related to a decrease in motor performance and changes in excitability and connectivity strength within cerebral sensorimotor circuits, we aimed to explore whether aging affects EEG-MEP interactions. Using MRI-navigated TMS and multichannel EEG, we compared the EEG-MEP interactions observed in healthy aged subjects with those observed in young volunteers. We divided the MEPs amplitude into two different subgroups consisting of "high" and "low" MEPs, based on the 50th percentile of their amplitude distribution. Then we analysed the characteristics of the pre-stimulus EEG from M1 and correlated areas separately for the "high" and "low" MEPs, comparing the two conditions. In both young and old subjects, significantly larger MEPs were evoked when the stimulated M1 was coupled in the beta-2 band with the homolateral prefrontal cortex. Conversely, only in young participants was the MEP size modulated when the M1 and homolateral parieto-occipital cortices were coupled in the delta band. The elderly didn't show this kind of pattern. Importantly, this coupling was significantly higher in elderly brains than in young brains, both for high and low MEPs. Our results suggest an age-related significant influence of time-varying coupling of spatially patterned EEG rhythms on motor cortex excitability in response to TMS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The co-registration of transcranial magnetic stimulation and electroencephalography (TMS-EEG) is emerging as a successful technique for causally exploring cortical mechanisms and connections. However, various artefacts could affect TMS-EEG signals. Correct artefacted channels reconstruction is crucial to obtain accurate topographical representation and consequently accurate inverse problem solution, in order to map in a proper way the global brain responses after the stimulation of one particular brain region of interest. In this paper, we discuss the problem of artefacted channels interpolation in TMS-EEG signals. Aim of the study was to investigate two different interpolation methods evaluating their performance in two datasets: one constituted by 19 EEG channels montage (low-density spatial resolution) and the other one by 60 EEG channels montage (high-density spatial resolution). In addition, these evaluations took place in two different contexts of application: after the averaging of TMS Evoked Potentials (TEPs) in a time interval to obtain a global information in the considered range, and at fixed latencies 100 ms and 300 ms after the TMS stimulus. The results showed that the global reconstruction error was lower at fixed latencies for the high-density electrodes spatial resolution montage.

The last years have witnessed a significant increase in our understanding of brain functions in survivors of severe brain injuries with disorders of consciousness (DOC). Despite there is currently no effective standardized treatment for DOC patients, in the past decade many potential pharmacological as well as non-pharmacological therapies have been proposed. A promising and increasingly growing field of non-pharmacological therapeutic trials has been supported by the application of electrophysiological techniques. This article reviews the most relevant studies in the literature in order to provide the reader with a clear picture of the current available neurophysiological instruments that could be used to treat DOC patients. We will hereinafter briefly discuss the basic principles of deep brain stimulation (DBS), repetitive transcranial magnetic stimulation (rTMS), spinal cord stimulation (SCS) and peripheral nerve stimulation (MNS) that are the main techniques now used by researchers as a treatment and we will explain the rationale of these therapies. Then, we will outline the more relevant studies regarding their application in DOC patients. Finally, due to the fact that only a moderate amount of individual or clinically-dependent approaches are available, we conclude that more standardized studies are necessary to address the role of electrophysiological treatment strategies in DOC as well as to further elucidate their therapeutic effects and define optimal stimulation parameters. Undoubtedly, at present the multidimensional approach is the most interesting.

Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark-light) cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C) temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry (MS) demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole MS indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid (PA) and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD) is a family of enzymes that hydrolyzes phospholipids to produce PA. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of PA. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.

The working memory functions and processing speed of 35 adolescents born preterm (< or = 32 weeks of gestation) and those of 31 control adolescents were assessed at the age of 16 years. All study participants were free from major disabilities. There were no statistically significant differences in verbal IQ between the study groups. Adolescents born preterm performed less well in complex spatial span compared to their peers born full term, even when verbal IQ and processing speed were allowed to covary. Both groups performed equally well in other working memory tasks and processing speed. Gestational age was the primary contributor to spatial span performance. These results indicate a minor spatial working memory deficit in preterm born adolescents without major disability and with normal cognitive capacity. Our results are encouraging and indicate only minor neuropsychological consequences due to very preterm birth.

Although oxylipins can be synthesized from free fatty acids, recent evidence suggests that oxylipins are components of plastid-localized polar complex lipids in Arabidopsis (Arabidopsis thaliana). Using a combination of electrospray ionization (ESI) collisionally induced dissociation time-of-flight mass spectrometry (MS) to identify acyl chains, ESI triple-quadrupole (Q) MS in the precursor mode to identify the nominal masses of complex polar lipids containing each acyl chain, and ESI Q-time-of-flight MS to confirm the identifications of the complex polar lipid species, 17 species of oxylipin-containing phosphatidylglycerols, monogalactosyldiacylglycerols (MGDG), and digalactosyldiacylglycerols (DGDG) were identified. The oxylipins of these polar complex lipid species include oxophytodienoic acid (OPDA), dinor-OPDA (dnOPDA), 18-carbon ketol acids, and 16-carbon ketol acids. Using ESI triple-Q MS in the precursor mode, the accumulation of five OPDA- and/or dnOPDA-containing MGDG and two OPDA-containing DGDG species were monitored as a function of time in mechanically wounded leaves. In unwounded leaves, the levels of these oxylipin-containing complex lipid species were low, between 0.001 and 0.023 nmol/mg dry weight. However, within the first 15 min after wounding, the levels of OPDA-dnOPDA MGDG, OPDA-OPDA MGDG, and OPDA-OPDA DGDG, each containing two oxylipin chains, increased 200- to 1,000-fold. In contrast, levels of OPDA-hexadecatrienoic acid MGDG, linolenic acid (18:3)-dnOPDA MGDG, OPDA-18:3 MGDG, and OPDA-18:3 DGDG, each containing a single oxylipin chain, rose 2- to 9-fold. The rapid accumulation of high levels of galactolipid species containing OPDA-OPDA and OPDA-dnOPDA in wounded leaves is consistent with these lipids being the primary products of plastidic oxylipin biosynthesis.