Distinctive Neuroanatomical Substrates for Depression in Bipolar Disorder versus Major Depressive Disorder

Abstract

No neuroanatomical substrates for distinguishing between depression of bipolar disorder (dBD) and major depressive disorder (dMDD) are currently known. The aim of the current multicenter study was to identify neuroanatomical patterns distinct to depressed patients with the two disorders. Further analysis was conducted on an independent sample to enable generalization of results. We directly compared MR images of these subjects using voxel-based morphometry (VBM) and a support vector machine (SVM) algorithm using 1531 participants. The VBM analysis showed significantly reduced gray matter volumes in the bilateral dorsolateral prefrontal (DLPFC) and anterior cingulate cortices (ACC) in patients with dBD compared with those with dMDD. Patients with the two disorders shared small gray matter volumes for the right ACC and left inferior frontal gyrus when compared with healthy subjects. Voxel signals in these regions during SVM analysis contributed to an accurate classification of the two diagnoses. The VBM and SVM results in the second cohort also supported these results. The current findings provide new evidence that gray matter volumes in the DLPFC and ACC are core regions in displaying shared and distinct neuroanatomical substrates and can shed light on elucidation of neural mechanism for depression within the bipolar/major depressive disorder continuum.

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Atomic worlds: Current state and future of atom probe tomography in geoscience

Publication date: Available online 29 November 2017
Source:Scripta Materialia
Author(s): D.W. Saxey, D.E. Moser, S. Piazolo, S.M. Reddy, J.W. Valley
Atom Probe Tomography (APT) is rapidly finding new applications within the geosciences. Historically connected with materials science and semiconductor device applications, recent years have seen APT established as a useful tool for nanoscale geochemistry, offering unique capabilities when compared with conventional geoanalytical techniques. The ability to characterize 3D nanoscale chemistry with isotopic sensitivity has uncovered intricate details of complex trace element distributions within a variety of minerals. Already these advances are having an impact on long-standing questions within geochronology, planetary science and other fields. Future developments are likely to bring significant expansion in this research space.



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Characteristics and health risk assessment of heavy metals exposure via household dust from urban area in Chengdu, China

Publication date: 1 April 2018
Source:Science of The Total Environment, Volumes 619–620
Author(s): Zhang Cheng, Liu-Jun Chen, Han-Han Li, Jian-Qing Lin, Zhan-Biao Yang, Yuan-Xiang Yang, Xiao-Xun Xu, Jun-Ren Xian, Ji-Rong Shao, Xue-Mei Zhu
To investigate the characteristics of heavy metals (Cr, Cd, Pb, Zn, Cu and Ni) in household dust in urban household environment of Chengdu, China, 90 household dust samples were collected from 6 districts of the city. The information of houses and residents were also recorded during dust sampling to identify the correlations between heavy metals in household dust and the house attributes. And also the principal component analysis and cluster analysis for sources and impactor factors. The concentrations of Pb (123mg·kg⁻¹), Zn (675mg·kg⁻¹), Cu (190mg·kg⁻¹), Cr (82.7mg·kg⁻¹), Cd (2.37mg·kg⁻¹) and Ni (52.6mg·kg⁻¹) in household dust are in low or moderate levels when compare with that from other counties or areas. The heavy metals of household dust samples from Chengdu is higher concentrations than that in the street dust from Chengdu, except for Cr. Statistical analysis result showed traffic sources and corrosion of alloys are important factors contributing to the rise concentrations of heavy metals in household dust. In addition, there is negative correlation (p<0.05) between the heavy metals concentrations and floor levels. The ingestion is the important pathway for Pb, Zn, Cu and Ni via household dust exposure to the residents, and the dermal contact was identified as a main route for Cr and Cd in household dust exposure to the residents. There are minor non-carcinogenic and carcinogenic risks from the heavy metals in household dust for the residents in Chengdu.

Graphical abstract

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Sorption, mobility, and bioavailability of PBDEs in the agricultural soils: Roles of co-existing metals, dissolved organic matter, and fertilizers

Publication date: 1 April 2018
Source:Science of The Total Environment, Volumes 619–620
Author(s): Xuan Zhu, Jingzi Beiyuan, Abbe Y.T. Lau, Season S. Chen, Daniel C.W. Tsang, Nigel J.D. Graham, Daohui Lin, Jianteng Sun, Yanheng Pan, Xin Yang, Xiang-Dong Li
Polybrominated diphenyl ethers (PBDEs) are common pollutants released from electronic waste (e-waste) dismantling and recycling activities. Our city-wide survey of agricultural soils in Qingyuan (40 sampling sites), where e-waste recycling has been active, observed exceedance of PBDEs above background levels (average of 251.9ngg⁻¹, 87 times the regional baseline concentration) together with elevated levels of metals/metalloids at the contamination hotspots, such as As (180.4mgkg⁻¹), Cu (100.7mgkg⁻¹), Zn (93.4mgkg⁻¹), Pb (37.8mgkg⁻¹), Cr (15.1mgkg⁻¹), and Cd (0.3mgkg⁻¹). Hence, a twenty-cycle batch sorption test on composite soil samples from the e-waste site was conducted to study the fate of BDE-28 (2,4,4′-tribromodiphenyl ether) and BDE-99 (2,2′,4,4′,5-pentabromodiphenyl ether) under the influence of co-existing trace elements (TEs) (Cu, Pb, Zn, and Cd, which exceeded Chinese Environmental Quality Standard for Soils), dissolved organic matter (extracted from local peat), and locally available commercial fertilizer. The results showed that the presence of TEs barely affected the sorption of BDEs, probably because the low concentration of BDEs in the environment resulted in nearly complete sorption onto the soil. In contrast, metals sorption onto soil was promoted by the presence of BDEs. The mobility of BDE-28 was higher than BDE-99 in water leaching tests, while the leaching concentration of BDE-99 was further reduced in simulated acid rain possibly due to protonation of π-accepting sites in soil organic matter. In the freshly spiked soil, BDEs of greater hydrophobicity and larger molecular size exhibited higher bioavailability (due to greater affinity to Tenax extraction), which was contrary to the field contaminated soil. Similarly, the co-occurrence of metals and fertilizer increased the bioavailability of newly sorbed BDE-99 more than BDE-28 in the soil. These results illustrate the need to holistically assess the fate and interactions of co-existing organic and inorganic pollutants in the agricultural soils.

Graphical abstract

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Lead and other heavy metals in soils impacted by exterior legacy paint in residential areas of south west England

Publication date: 1 April 2018
Source:Science of The Total Environment, Volumes 619–620
Author(s): Andrew Turner, Madeleine Lewis
Legacy paint on publicly-accessible structures in residential areas of Plymouth, UK (a bridge parapet, hospital railings, a goal frame, urban street paving and a telephone kiosk) and local paint-contaminated soils have been analysed for lead and other heavy metals (chromium, zinc and barium) by X-ray fluorescence spectrometry. Lead was detected in all paints analysed (n=56) apart from two fragments of yellow road markings, with maximum concentrations exceeding 300gkg⁻¹. Soils were contaminated by Pb to varying degrees that depended on the condition and Pb content of the paint applications and the nature and vegetation of the soil, with a maximum concentration of 27gkg⁻¹ and a maximum enrichment factor normalised to grain size and regional baseline soil of 270. While Cr showed no clear contamination in soils that could be attributed to paint, contamination from this source was evident for Zn in soil by the goal frame and for Ba and Zn in soil by the bridge parapet. Application of a physiologically-based extraction test to the soils revealed stomach bioaccessibilities that were variable among the samples and between the metals but that were greatest for Zn and lowest for Cr. With the exception of Cr, bioaccessibility generally decreased in the intestine, with mean intestinal bioaccessibilities relative to total metal of about 6% for Pb and Ba, 0.9% for Cr and 1.6% for Zn. From both a health and environmental perspective, Pb is the heavy metal of greatest concern because of its common occurrence at high concentrations in legacy paints, coupled with a relatively high bioaccessibility and well-documented chronic neurotoxicity. Public exposure to Pb in residential areas may arise through direct contact with paint or soil or via the intrusion of contaminated geosolids to the household on shoes or as airborne dust.

Graphical abstract

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Motor cortex Transcranial Direct Current Stimulation (tDCS) improves acute stroke visuo-spatial neglect: A series of four case reports

Publication date: Available online 29 November 2017
Source:Brain Stimulation
Author(s): S. Bornheim, P. Maquet, J.L. Croisier, J.M. Crielaard, J.F. Kaux




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TMS over posterior parietal cortex disrupts trans-saccadic visual stability

Publication date: Available online 29 November 2017
Source:Brain Stimulation
Author(s): Thérèse Collins, Pierre O. Jacquet
BackgroundSaccadic eye movements change the retinal location of visual objects, but we do not experience the visual world as constantly moving, we perceive it as seamless and stable. This visual stability may be achieved by an internal or efference copy of each saccade that, combined with the retinal information, allows the visual system to cancel out or ignore the self-caused retinal motion.ObjectiveThe current study investigated the underlying brain mechanisms responsible for visual stability in humans with online transcranial magnetic stimulation (TMS).MethodsWe used two classic tasks that measure efference copy: the double-step task and the in-flight displacement task. The double-step task requires subjects to make two memory-guided saccades, the second of which depends on an accurate internal copy of the first. The in-flight displacement task requires subjects to report the relative location of a (possibly displaced) target across a saccade. In separate experimental sessions, subjects participated in each task while we delivered online 3-pulse TMS over frontal eye fields (FEF), posterior parietal cortex, or vertex. TMS was contingent on saccade execution.ResultsSecond saccades were not disrupted in the double-step task, but surprisingly, TMS over FEF modified the metrics of the ongoing saccade. Spatiotopic performance in the in-flight displacement task was altered following TMS over parietal cortex, but not FEF or vertex.ConclusionThese results suggest that TMS disrupted eye-centered position coding in the parietal cortex. Trans-saccadic correspondence, and visual stability, may therefore causally depend on parietal maps.



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