Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study

AbstractBackgroundA common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-dependent (BOLD) signal changes across the whole brain linked to vertex stimulation.MethodsThirty-two healthy participants to part in this study. Twenty-one were stimulated at the vertex, at 120% of resting motor threshold (RMT), with short bursts of 1 Hz TMS, while functional magnetic resonance imaging (fMRI) BOLD images were acquired. As a control condition, we delivered TMS pulses over the left primary motor cortex using identical parameters to 11 other participants.ResultsVertex stimulation did not evoke increased BOLD activation at the stimulated site. By contrast we observed widespread BOLD deactivations across the brain, including regions within the default mode network (DMN). To examine the effects of vertex stimulation a functional connectivity analysis was conducted.ConclusionThe results demonstrated that stimulating the vertex with suprathreshold TMS reduced neural activity in brain regions related to the DMN but did not influence the functional connectivity of this network. Our findings provide brain imaging evidence in support of the use of vertex simulation as a control condition in TMS but confirm that vertex TMS induces regional widespread decreases in BOLD activation

Gasification of non-woody biomass: a literature review

Non-woody biomass, having a lower lignin content than woody materials, is a common waste material found in agricultural processing plants and fields. Non-woody biomass is often bulky and has a comparatively low energy content. However, non-woody materials sourced from agricultural waste are abundant and cheap. Experimental studies into gasification of non-woody biomass have been conducted by various researchers. This paper reviews feedstock characteristics, pre-treatments, gasification methods, and future directions of this technology. Due to the heterogeneous nature of non-woody biomass, it is critical to apply suitable pre-treatments prior to gasification. Combining non-woody biomass with a small percentage of high grade carbon sourced from biochar or coal into fuel pellets for co-gasification has the potential to improve fuel quality. Synergistic effects of non-woody biomass-coal/charcoal co-gasification can also reduce tar formation and increase the occurrence of mineral based catalytic reactions. Factors influencing these effects are often complex and require further investigation. 15–20% of the energy content of fuel pellets may be needed to power the biomass pre-treatment process. The gasification of pelletised non-woody waste provides an attractive alternative fuel source to achieve agricultural energy self-sufficiency and off-grid operation

Lower body acceleration and muscular responses to rotational and vertical whole-body vibration of different frequencies and amplitudes

This is the final version. Available on open access from SAGE Publications via the DOI in this recordThe aim of this study was to characterise acceleration transmission and neuromuscular responses to rotational (RV) and vertical (VV) vibration of different frequencies and amplitudes. Methods - 12 healthy males completed 2 experimental trials (RV vs. VV) during which vibration was delivered during either squatting (30°; RV vs. VV) or standing (RV only) with 20, 25, 30 Hz, at 1.5 and 3.0 mm peak-to-peak amplitude. Vibration-induced accelerations were assessed with triaxial accelerometers mounted on the platform and bony landmarks at ankle, knee, and lumbar spine. Results At all frequency/amplitude combinations, accelerations at the ankle were greater during RV (all p < 0.03) with the greatest difference observed at 30 Hz 1.5 mm. Transmission of RV was also influenced by body posture (standing vs. squatting, p < 0.03). Irrespective of vibration type vibration transmission to all skeletal sites was generally greater at higher amplitudes but not at higher frequencies, especially above the ankle joint. Acceleration at the lumbar spine increased with greater vibration amplitude but not frequency and was highest with RV during standing. Conclusions/Implications - The transmission of vibration during WBV is dependent on intensity and direction of vibration as well as body posture. For targeted mechanical loading at the lumbar spine, RV of higher amplitude and lower frequency vibration while standing is recommended. These results will assist with the prescription of WBV to achieve desired levels of mechanical loading at specific sites in the human body.London South Bank UniversityAge U

Enhanced task-related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation

© 2017, Canadian Science Publishing. All rights reserved. Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties. High flavonoid intakes attenuate age-related cognitive decline, but data from human intervention studies are sparse. We investigated whether 12 weeks of blueberry concentrate supplementation improved brain perfusion, task-related activation, and cognitive function in healthy older adults. Participants were randomised to consume either 30 mL blueberry concentrate providing 387 mg anthocyanidins (5 female, 7 male; age 67.5 ± 3.0 y; body mass index, 25.9 ± 3.3 kg·m−2) or isoenergetic placebo (8 female, 6 male; age 69.0 ± 3.3 y; body mass index, 27.1 ± 4.0 kg·m−2). Pre-and postsupplementation, participants undertook a battery of cognitive function tests and a numerical Stroop test within a 1.5T magnetic resonance imaging scanner while functional magnetic resonance images were continuously acquired. Quantitative resting brain perfusion was determined using an arterial spin labelling technique, and blood biomarkers of inflammation and oxidative stress were measured. Significant increases in brain activity were observed in response to blueberry supplementation relative to the placebo group within Brodmann areas 4/6/10/ 21/40/44/45, precuneus, anterior cingulate, and insula/thalamus (p < 0.001) as well as significant improvements in grey matter perfusion in the parietal (5.0 ± 1.8 vs-2.9 ± 2.4%, p = 0.013) and occipital (8.0 ± 2.6 vs-0.7 ± 3.2%, p = 0.031) lobes. There was also evidence suggesting improvement in working memory (2-back test) after blueberry versus placebo supplementation (p = 0.05). Supplementation with an anthocyanin-rich blueberry concentrate improved brain perfusion and activation in brain areas associated with cognitive function in healthy older adults

Tart Cherry Concentrate Does Not Alter the Gut Microbiome, Glycaemic Control or Systemic Inflammation in a Middle-Aged Population.

This is the final version. available from MDPI via the DOI in this recordLimited evidence suggests that the consumption of polyphenols may improve glycaemic control and insulin sensitivity. The gut microbiome produces phenolic metabolites and increases their bioavailability. A handful of studies have suggested that polyphenol consumption alters gut microbiome composition. There are no data available investigating such effects in polyphenol-rich Montmorency cherry (MC) supplementation. A total of 28 participants (aged 40-60 years) were randomized to receive daily MC or glucose and energy-matched placebo supplementation for 4 wk. Faecal and blood samples were obtained at baseline and at 4 wk. There was no clear effect of supplementation on glucose handling (Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and Gutt indices), although the Matsuda index decreased significantly in the MC group post-supplementation, reflecting an increase in serum insulin concentration. Contrastingly, placebo, but not MC supplementation induced a 6% increase in the Oral Glucose Insulin Sensitivity (OGIS) estimate of glucose clearance. Serum IL-6 and C reactive protein were unaltered by either supplement. The faecal bacterial microbiome was sequenced; species richness and diversity were unchanged by MC or placebo and no significant correlation existed between changes in Bacteroides and Faecalibacterium abundance and any index of insulin sensitivity. Therefore, 4 weeks of MC supplementation did not alter the gut microbiome, glycaemic control or systemic concentrations of IL-6 and CRP in a middle-aged population.The Cherry Marketing Institut

The Tumor Microenvironment of Clear-Cell Ovarian Cancer

Some patients with advanced clear-cell ovarian cancer (CCOC) respond to immunotherapy; however, little is known about the tumor microenvironment (TME) of this relatively rare disease. Here, we describe a comprehensive quantitative and topographical analysis of biopsies from 45 patients, 9 with Federation Internationale des Gynaecologistes et Obstetristes (FIGO) stage I/II (early CCOC) and 36 with FIGO stage III/IV (advanced CCOC). We investigated 14 immune cell phenotype markers, PD-1 and ligands, and collagen structure and texture. We interrogated a microarray data set from a second cohort of 29 patients and compared the TMEs of ARID1A-wildtype (ARID1A(wt)) versus ARID1A-mutant (ARID1A(mut)) disease. We found significant variations in immune cell frequency and phenotype, checkpoint expression, and collagen matrix between the malignant cell area (MCA), leading edge (LE), and stroma. The MCA had the largest population of CD138(+) plasma cells, the LE had more CD20(+) B cells and T cells, whereas the stroma had more mast cells and αSMA(+) fibroblasts. PD-L2 was expressed predominantly on malignant cells and was the dominant PD-1 ligand. Compared with early CCOC, advanced-stage disease had significantly more fibroblasts and a more complex collagen matrix, with microarray analysis indicating “TGFβ remodeling of the extracellular matrix” as the most significantly enriched pathway. Data showed significant differences in immune cell populations, collagen matrix, and cytokine expression between ARID1A(wt) and ARID1A(mut) CCOC, which may reflect different paths of tumorigenesis and the relationship to endometriosis. Increased infiltration of CD8(+) T cells within the MCA and CD4(+) T cells at the LE and stroma significantly associated with decreased overall survival

Heschl's gyrus is more sensitive to tone level than non-primary auditory cortex

Previous neuroimaging studies generally demonstrate a growth in the cortical response with an increase in sound level. However, the details of the shape and topographic location of such growth remain largely unknown. One limiting methodological factor has been the relatively sparse sampling of sound intensities. Additionally, most studies have either analysed the entire auditory cortex without differentiating primary and non-primary regions or have limited their analyses to Heschl's gyrus (HG). Here, we characterise the pattern of responses to a 300-Hz tone presented in 6-dB steps from 42 to 96 dB sound pressure level as a function of its sound level, within three anatomically defined auditory areas; the primary area, on HG, and two non-primary areas, consisting of a small area lateral to the axis of HG (the anterior lateral area, ALA) and the posterior part of auditory cortex (the planum temporale, PT). Extent and magnitude of auditory activation increased non-linearly with sound level. In HG, the extent and magnitude were more sensitive to increasing level than in ALA and PT. Thus, HG appears to have a larger involvement in sound-level processing than does ALA or PT

Montmorency cherry supplementation attenuates vascular dysfunction induced by prolonged forearm occlusion in overweight, middle-aged men

Flavonoid supplementation improves brachial artery flow-mediated dilation (FMD), but it is not known whether flavonoids protect against vascular dysfunction induced by ischemia-reperfusion (IR) injury and associated respiratory burst. In a randomized, double-blind, placebo-controlled, crossover study, we investigated whether 4 wk supplementation with freeze-dried Montmorency cherry (MC) attenuated suppression of FMD after IR induced by prolonged forearm occlusion. Twelve physically inactive overweight, middle-aged men (52.8 ± 5.8 yr, BMI: 28.1 ± 5.3 kg/m2) consumed MC (235 mg/day anthocyanins) or placebo capsules for 4 wk, with supplementation blocks separated by 4 wk washout. Before and after each supplementation block, FMD responses and plasma nitrate and nitrite ([ N O − 2 ]) concentrations were measured at baseline and 15, 30, and 45 min after prolonged (20 min) forearm occlusion. FMD response was significantly depressed by the prolonged occlusion ( P < 0.001). After a 45-min reperfusion, FMD was restored to baseline levels after MC (ΔFMD presupplementation: -30.5 ± 8.4%, postsupplementation: -0.6 ± 9.5%) but not placebo supplementation (ΔFMD presupplementation: -11.6 ± 10.6, postsupplementation: -25.4 ± 4.0%; condition × supplement interaction: P = 0.038). Plasma [ N O − 2 ] decreased after prolonged occlusion but recovered faster after MC compared with placebo (Δ45 min to baseline; MC: presupplementation: -15.3 ± 9.6, postsupplementation: -6.2 ± 8.1; Placebo: presupplementation: -16.3 ± 5.9, postsupplementation: -27.7 ± 11.1 nmol/l; condition × supplement × time interaction: P = 0.033). Plasma peroxiredoxin concentration ([Prx2]) was significantly higher after MC (presupplementation: 22.8 ± 1.4, postsupplementation: 28.0 ± 2.4 ng/ml, P = 0.029) but not after placebo supplementation (presupplementation: 22.1 ± 2.2, postsupplementation: 23.7 ± 1.5 ng/ml). In conclusion, 4 wk MC supplementation enhanced recovery of endothelium-dependent vasodilatation after IR, in parallel with faster recovery of plasma [ N O − 2 ], suggesting NO dependency. These protective effects seem to be related to increased plasma [Prx2], presumably conferring protection against the respiratory burst during reperfusion. NEW & NOTEWORTHY This is the first study to demonstrate that 4 wk of Montmorency cherry powder supplementation exerted protective effects on endothelium-dependent vasodilation after transient ischemia-reperfusion injury in overweight, physically inactive, nonmedicated, hypertensive middle-aged men. These effects seem to be due to increased nitric oxide availability, as evidenced by higher plasma nitrite concentration and peak arterial diameter during the flow-mediated dilation measurement. This may be a consequence of increased concentration of peroxiredoxin and other antioxidant systems and, hence, reduced reactive oxygen species exposure.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.This study was partially funded by a grant from the Cherry Research Committee, Aboo-Bakkar was supported by a Ph.D. studentship from the Universiti Kuala Lumpur, and Fulford’s salary was provided by National Institute for Health Research.accepted version (12 month embargo

Design and testing of microbubble‐based MRI contrast agents for gastric pressure measurement

Purpose: This work demonstrates specifically tailored microbubble‐based preparations and their suitability as MRI contrast agents for ingestion and measuring temporal and spatial pressure variation in the human stomach. Methods: Enhanced alginate spheres were prepared by incorporating gas‐filled microbubbles into sodium alginate solution followed by the polymerization of the mixture in an aqueous calcium lactate solution. The microbubbles were prepared with a phospholipid shell and perfluorocarbon gas filling, using a mechanical cavitational agitation regime. The NMR signal changes to externally applied pressure and coming from the enhanced alginate spheres were acquired and compared with that of alginate spheres without microbubbles. In vivo investigations were also carried out on healthy volunteers to measure the pressure variation in the stomach. Results: The MR signal changes in the contrast agent exhibits a linear sensitivity of approximately 40% per bar, as opposed to no measurable signal change seen in the control gas‐free spheres. This novel contrast agent also demonstrates an excellent stability in simulated gastric conditions, including at body temperature. In vivo studies showed that the signal change exhibited in the meal within the antrum region is between 5% and 10%, but appears to come from both pressure changes and partial volume artifacts. Conclusion: This study demonstrates that alginate spheres with microbubbles can be used as an MRI contrast agent to measure pressure changes. The peristaltic movement within the stomach is seen to substantially alter the overall signal intensity of the contrast agent meal. Future work must focus on improving the contrast agent's sensitivity to pressure changes

Imaging the human hippocampus with optically-pumped magnetoencephalography

Optically-pumped (OP) magnetometers allow magnetoencephalography (MEG) to be performed while a participant’s head is unconstrained. To fully leverage this new technology, and in particular its capacity for mobility, the activity of deep brain structures which facilitate explorative behaviours such as navigation, must be detectable using OP-MEG. One such crucial brain region is the hippocampus. Here we had three healthy adult participants perform a hippocampal-dependent task – the imagination of novel scene imagery – while being scanned using OPMEG. A conjunction analysis across these three participants revealed a significant change in theta power in the medial temporal lobe. The peak of this activated cluster was located in the anterior hippocampus. We repeated the experiment with the same participants in a conventional SQUID-MEG scanner and found similar engagement of the medial temporal lobe, also with a peak in the anterior hippocampus. These OP-MEG findings indicate exciting new opportunities for investigating the neural correlates of a range of crucial cognitive functions in naturalistic contexts including spatial navigation, episodic memory and social interactions