Investigating cortical activity during cybersickness by fNIRS.

This study investigated brain responses during cybersickness in healthy adults using functional near-infrared spectroscopy (fNIRS). Thirty participants wore a head-mounted display and observed a virtual roller coaster scene that induced cybersickness. Cortical activation during the virtual roller coaster task was measured using fNIRS. Cybersickness symptoms were evaluated using a Simulator Sickness Questionnaire (SSQ) administered after the virtual rollercoaster. Pearson correlations were performed for cybersickness symptoms and the beta coefficients of hemodynamic responses. The group analysis of oxyhemoglobin (HbO) and total hemoglobin (HbT) levels revealed deactivation in the bilateral angular gyrus during cybersickness. In the Pearson correlation analyses, the HbO and HbT beta coefficients in the bilateral angular gyrus had a significant positive correlation with the total SSQ and disorientation. These results indicated that the angular gyrus was associated with cybersickness. These findings suggest that the hemodynamic response in the angular gyrus could be a biomarker for evaluating cybersickness symptoms.

Effects of Transcranial Direct Current Stimulation on Clinical Features of Dizziness and Cortical Activation in a Patient with Vestibular Migraine.

BACKGROUND: Vestibular migraine (VM) is common migraine that occurs in patients with dizziness. Vestibular rehabilitation for managing VM generally remains unclear. Recently, it has been reported that transcranial direct current stimulation (tDCS) has positive effects in alleviating dizziness. This study investigated the effects of tDCS on dizziness and cortical activation in a patient with VM. METHODS: We recruited a male patient aged 31 years with no dizziness. The patient watched a video to induce dizziness using a virtual reality device. The study applied the intervention using tDCS for 4 weeks and measured 4 assessments: functional near-infrared spectroscopy (fNIRS), quantitative electroencephalography (qEEG), dizziness handicap inventory, and visual vertigo analog scale. RESULTS: We showed the activation in the middle temporal gyrus and inferior temporal gyrus (ITG) of the left hemisphere and in the superior temporal gyrus and ITG of the right hemisphere in the pre-intervention. After the intervention, the activation of these areas decreased. In the results of qEEG, excessive activation of C3, P3, and T5 in the left hemisphere and C4 in the right hemisphere before intervention disappeared after the intervention. CONCLUSIONS: This study indicated that tDCS-based intervention could be considered a viable approach to treating patients with vestibular dysfunction and dizziness caused by VM.

Sensorimotor adaptation in spatial orientation task: a fNIRS study.

In sensorimotor conflicts, the brain forms and updates a new sensorimotor relationship through sensorimotor integration. As humans adapt to new sensorimotor mapping, goal-directed movements become increasingly precise. Using functional near-infrared spectroscopy, we investigated the changes in cortical activity during sensorimotor adaptation in a spatial orientation task with sensorimotor conflict. Individuals performed a reversed spatial orientation training in which the visual feedback guiding hand movements was reversed. We measured cortical activity and spatial orientation performance, including the response time, completion number, error, and accuracy. The results revealed the continuous activation in the left SMG during sensorimotor adaptation and decreased activation in the right SAC, AG and SMG after sensorimotor adaptation. These findings indicated the contribution of the left SMG to sensorimotor adaptation and the improved efficiency of cortical activity after sensorimotor adaptation, respectively. Our studies suggest the neural mechanisms related to sensorimotor adaptation to a reversed spatial orientation task.

Motor Imagery Combined With Physical Training Improves Response Inhibition in the Stop Signal Task.

Background: Motor imagery training has a similar effect to that of physical training on motor performance. The objective of this study was to investigate the short-term effectiveness of motor imagery training on response inhibition using the stop signal task (SST). Methods: Participants were divided into a physical training group (PT, n = 17), a motor imagery training group (MIT, n = 17), and a motor imagery combined with physical training group (MIPT, n = 17). All participants performed 10 SST training sessions over 5 days. Both stop signal reaction time (SSRT) and non-signal reaction time (NSRT) were measured before and after SST training. Results: There were significant interaction (time × group) and time effects, although the group effect was not statistically significant. Bonferroni post hoc analysis showed that MIPT group revealed a significantly greater change in SSRT than PT and MIT groups, while there was no significant difference between PT and MIT groups. SSRT significantly decreased after training in all groups. In NSRT, there was a significant effect of time, but there was no significant interaction effect (time × group) or group effect. Conclusion: Response inhibition could be enhanced via training, and it was most effective when motor imagery and physical training were combined. We demonstrate that motor imagery training significantly improves response inhibition and should be accompanied by physical training when performing SST.

Comparison of forward versus backward walking on spatiotemporal and kinematic parameters on sand: A preliminary study.

The purpose of this study was to investigate the spatiotemporal and kinematic parameters of backward walking (BW) and forward walking (FW) on sand. Randomly selected subjects (n = 28) were categorized into a sand group (SG, n = 14) and an overground group (OG, n = 14). SG was directed to perform both FW and BW on sand, while OG performed the same on the overground. Spatiotemporal and kinematic parameters were measured using the LegSys + device. The comparative findings of both the groups showed that the spatiotemporal parameters of SG varied significantly from those of OG in both FW and BW conditions (p < 0.05). The kinematic parameters varied significantly between the two groups only in the FW condition (p < 0.05). When compared within each group, spatiotemporal and kinematic parameters in the BW condition were significantly different from those in the FW condition. However, the percentages of stance, swing, and double support were not significantly different between FW and BW conditions (p > 0.05). This study suggests that sand walking is associated with a different gait pattern than overground walking, as evident from the analysis of the results of spatiotemporal and kinematic parameters in both FW and BW conditions. Therefore, sand walking can be used as a new approach to gait and balance training in clinical practice.

Changes in the aquatic ecotoxicological effects of Triton X-100 after UV photodegradation.

Various spray adjuvants including surfactants are widely used in agricultural pesticide formulations, and some of them may remain in soils and waters and impose more adverse effects than active pesticide ingredients on organisms. However, previous studies are more focused on the active pesticide ingredients than the adjuvants. Thus, this study investigates the changes in toxic effects of surfactants during photodegradation, which is one way of naturally degrading contaminants in natural waters. Triton X-100, a water-soluble non-ionic surfactant, was degraded using different types of UV radiation (UVA, UVB, and UVC), and the changes in the toxic effects were determined using bioluminescent bacteria and water flea. The Triton X-100 removals were negligible with UVA within 24 h, while its removal was 81% with UVB and almost complete with UVC. The NMR spectra indicated possible molecule rearrangement after photolysis. On the other hand, the toxic effects based on the mortality of Daphnia magna and the bioluminescence of Aliivibrio fischeri increased (i.e., lower EC50 values) after photodegradation, suggesting the generation of photoproducts that are likely to have higher toxic effects or higher bioavailability. Furthermore, the sensitivities of D. magna and A. fischeri for Triton X-100 and the photodegraded Triton X-100 were different. This study suggests that the changes in the chemical composition of the Triton X-100 containing water with photodegradation can lead to changes in the relative toxic effects on different aquatic organisms. Therefore, not only the management of parent compound (i.e., Triton X-100) but also the photoproducts generated from the parent compound need to be considered when managing water environment subject to photodegradation.

Photodegradation of tetracycline and sulfathiazole individually and in mixtures.

Antibiotics in environment can be of concern as they can enter the food chain posing risks to ecosystems and human health. Photodegradation has been considered as a promising way of naturally degrading antibiotics in environment. Antibiotics are usually present in mixtures in environment; however, previous studies focused on individual compounds. Therefore, this study investigated the effect of UV irradiation on the degradation of tetracycline (TC) and sulfathiazole (STH) in individual solutions and mixtures. Under dark conditions, the initial masses of TC and STH were reduced by about 35% and 26%, respectively, over a 35 d-reaction period. With UV irradiation TC and STH were completely removed within 14 d and 35 d, respectively, regardless of the initial concentrations. Both the TC and STH removals were faster (i.e., 2-4 times) when they were in mixtures. This may be partly attributed to the byproducts such as sulfate that can promote indirect photolysis and partly to the enhanced hydrolysis due to changes in the solution pH. Overall, this study suggests that when photodegradation is used to remove antibiotics in water, the removal kinetics of antibiotics individually and in mixtures can be considered to develop more efficient treatment technologies.

Echinacea purpurea Protects Against Restraint Stress-Induced Immunosuppression in BALB/c Mice.

Echinacea purpurea has been widely used for the prevention and treatment of upper respiratory tract infections and the common cold. The restraint stress has been reported to suppress a broad spectrum of immune functions. The aim of this study was to investigate the protective effects of the pressed juice of E. purpurea (L.) Moench (EFLA®894; Echinacea) against restraint stress-induced immunosuppression in BALB/c mice. Echinacea significantly normalized the restraint stress-induced reduction in splenocyte proliferation and splenic natural killer (NK) cell activity (P < .05). Echinacea treatment significantly increased the percentages of CD4+ and CD8+ T lymphocytes in the blood (P < .05). In addition, Echinacea restored serum cytokine levels, including interleukin-6 (IL-6), interleukin-10 (IL-10), and interleukin-17 (IL-17), as well as the mRNA expressions of these cytokines in spleen (P < .05). Our findings suggest that Echinacea might have beneficial effects on restraint stress-induced immunosuppression by increasing splenocyte proliferation and NK cell activity, while modulating T lymphocyte subsets and cytokine levels in the blood.

Downregulation of Hepatic De Novo Lipogenesis and Adipogenesis in Adipocytes by Pinus densiflora Bark Extract.

Korean red pine (Pinus densiflora) bark extract, PineXol (PX), was investigated for its potential antioxidant and anti-inflammation effects in vitro. It was hypothesized that PX treatment (25-150 µg/ml) would reduce the lipid synthesis in HepG2 hepatocytes as well as lipid accumulation in 3T3-L1 adipocytes. Hepatocytes' intracellular triglycerides and cholesterol were decreased in the PX 150 µg/ml treatment group compared with the control (p < 0.05). Consequently, de novo lipogenic proteins (acetyl-CoA carboxylase 1, stearoyl-CoA desaturase 1, elongase of very long chain fatty acids 6, glycerol-3-phosphate acyltransferase 1, and sterol regulatory element-binding protein 1) were significantly decreased in hepatocytes by PX 150 µg/ml treatment compared with the control (p < 0.05). In differentiated 3T3-L1 adipocytes, the lipid accumulation was significantly attenuated by all PX treatments (p < 0.01). Regulators of adipogenesis, including CCAAT-enhancer-binding proteins alpha, peroxisome proliferator-activated receptor gamma, and perilipin, were decreased in PX 100 µg/ml treatment compared with the control (p < 0.05). In conclusion, PX might have anti-obesity effects by blocking hepatic lipogenesis and by inhibiting adipogenesis in adipocytes.

FlexPro MD, a Mixture of Krill Oil, Astaxanthin, and Hyaluronic Acid, Suppresses Lipopolysaccharide-Induced Inflammatory Cytokine Production Through Inhibition of NF-κB.

FlexPro MD® (FP-MD), a novel multi-ingredient dietary supplement formulation, has been demonstrated to relieve knee joint pain in humans. However, the mechanisms of action responsible for the activity of FP-MD have not been elucidated. In this study, we show the anti-inflammatory effects of FP-MD in RAW264.7 macrophage cells and mice challenged with lipopolysaccharide (LPS). FP-MD significantly inhibited the mRNA levels of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1ß. In contrast, it elevated the mRNA levels of anti-inflammatory cytokine IL-10 in LPS-stimulated RAW264.7 cells. FP-MD markedly reduced LPS-induced phosphorylation levels of nuclear factor-κB (NF-κB) p65 and inhibitor of κB-α (IκB-α). Importantly, the anti-inflammatory effects of FP-MD were demonstrated in mice with LPS-induced inflammatory arthritis in which FP-MD significantly reduced the expression levels of pro-inflammatory cytokines and inflammatory markers. Thus, this study suggests that FP-MD has anti-inflammatory effects by inhibiting NF-κB that may offer a molecular basis for its pain relief property.

Expression of thymosin ß4 in odontoblasts during mouse tooth development.

Thymosin ß4 (Tß4) is expressed in developing tissue, where it stimulates cell differentiation and migration. Further, Tß4 is expressed during molar development in mice, but the expression and function of Tß4 in odontoblasts during mammalian tooth development have not yet been reported. Therefore, this study examined the expression and function of Tß4 in differentiating odontoblasts during tooth development. As observed by immunohistochemistry, Tß4 was expressed in the oral epithelium and inside cells of the tooth bud on embryonic day 15 (E15). Further, on E17, Tß4 was expressed strongly in the dental lamina and oral epithelium, but only expressed in part of the cells in the outer and inner dental epithelium. Tß4 was strongly expressed in the entire cytoplasm of odontoblasts on postnatal day 1 (PN1) and expressed intensively in the apical area of odontoblasts on PN4. Further, expression of Tß4 was increased gradually in odontoblasts from PN1 to PN21. In an odontoblast cell line, MDPC-23, expression of Tß4 mRNA and protein was increased strongly on day 4 and gradually decreased from day 14. The gene expression of dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), osteocalcin (OCN), osteonectin (ON), and collagen type I, related with mineralization, was significantly decreased in si-Tß4/MDPC-23 during differentiation compared to that in MDPC-23 cells. Taken together, our results suggest that Tß4 may be involved in oral epithelial cell proliferation at the initial stage of tooth development and regulates the expression and secretion of proteins during odontoblast differentiation.