Contribution of Far Field Effects of Cortical tDCS in the Cerebellum to Learning in an Object Detection Paradigm

Transcranial direct current stimulation (tDCS) has been shown to enhance many cognitive and motor functions, and has been used in many areas, including rehabilitation of speech after stroke, cognitive enhancement, and treatment of mental illness. Our lab has demonstrated that, paired with training, anodal tDCS over electrode site F10 as well as cathodal tDCS over site T5 both increased the ability to detect hidden objects in a complex visual environment in a discovery learning paradigm. Stimulation of F10 has further been shown to enhance perceptual sensitivity selectively, without a change to response bias, and this effect was further enhanced when images presented during training were repeated in a post-training, post-stimulation test (Clark et al., 2012; Coffman et al., 2012; Falcone et al., 2012). Furthermore, this increased ability to detect hidden objects persisted for at least 24 hours Falcone et al., 2012). It has also been shown to increase measures of attention, using the Attention Network Task (ANT; Fan, 2002). Specifically, alerting network scores were increased in participants receiving active anode F10 stimulation compared to sham. Since both F10 anode as well as T5 cathode stimulation both resulted in increased learning the object detection task, potential additive effects were inferred, and an F10 anode/T5 cathode electrode montage was investigated. Surprisingly, this montage had an effect of about half of the other two montages (F10 anode/shoulder, T5 cathode/shoulder). Finite element current modeling studies were conducted to investigate more precisely where in the brain the electricity is traveling during these different stimulation protocols. Results suggested that both cephalic/extra-cephalic electrode placements exhibited far-field effects in subcortical areas, bilateral temporal poles, as well as in the cerebellum, albeit with opposite polarities. During F10 anode/shoulder cathode stimulation, a negative electrical field effect was seen in the cerebellum. During T5 cathode/shoulder anode stimulation, the opposite was true: there was a positive field effect in the cerebellum. However, the montage with a bi-cephalic placement showed no such effect in the cerebellum. Based on these modeling data, the difficulty of reaching subcortical areas with tDCS, and the evidence that the cerebellum is not only involved in motor behavior, but cognition as well, the cerebellum was chosen for direct stimulation with tDCS and was hypothesized to be contributing to the learning and attention effects reported in previous studies. Thirty-six participants received either anodal, cathodal, or sham stimulation of the medial posterior cerebellum during training to detect hidden objects in a complex visual environment. Measures of learning, signal detection, and interactions with stimulus type were investigated. Regression models were also built to investigate the contribution of each electrode placement in the two different montages. Measures of attention assessed with the ANT were also investigated. To our surprise, neither anodal nor cathodal stimulation of the cerebellum led to an increase in learning compared to sham stimulation. Furthermore, no effects were observed between groups on signal detection measures, nor was there an effect of group on stimulus type, all of which had previously been reported with F10 stimulation. Likewise, neither anode nor cathode stimulation led to an improvement on measures of attention compared to sham. The conclusion is that the cerebellum does not appear to be involved in the network contributing to learning and performing the object detection task. Although there were no direct effects of anodal or cathodal tDCS of the cerebellum on learning or attention, this study is an important step in elucidating the network involved in the robust finding of increased ability to detect hidden objects after administration of tDCS paired with training, as it rules out one potential contributor

Comparison of Post-Activation Potentiating Stimuli on Jump and Sprint Performance

Post-activation potentiation (PAP) is a phenomenon characterized by improved muscle performance based on the previous contractile activity of the muscle. The purpose of this study was to determine the effect of different potentiating stimuli on jump and sprint performance in 13 resistance trained, college-aged men and women. After determining back squat 1 repetition max, subjects returned for testing on separate days to complete one of four interventions (dynamic resistance, weighted plyometric, isometric, or control) in a randomized order. A standardized warmup was performed, followed by a baseline countermovement jump (CMJ) and 20m sprint. Following warm-up and baseline measurements, subjects performed one of the four experimental conditions. CMJ and 20m sprint measurements were completed again at 20-seconds, 4, 8, 12, 16, and 20-minutes. Results revealed significantly faster 0-20m sprint times (p \u3c .05) at the 4, 8, 12, 16, and 20-minute time points compared to baseline and 20-second time points. Significantly faster 0-20m sprint times (p \u3c .05) were also shown for the squat intervention compared to control at 4-minutes, the plyometric and squat intervention compared to control at 8-minutes, the isometric intervention compared to control at 12 and 16- minutes, and the isometric intervention compared to the squat at 20-minutes. These findings indicate that while all PAP stimuli utilized can be effective at improving sprint performance, specific optimal time points may exist

Home Care Nursing Visits and Same-Day Emergency Department Use: Which Patients Are Most at Risk?

Background Home care patients are a growing group of community-dwelling older adults with complex care needs and high health service use. Adult home care patients are at high risk for emergency department (ED) visits, which is greater on the same day as a nursing visit. The purpose of this study was to examine whether common nursing indicators modified the association between nursing visits and same-day ED visits. Methods A case-crossover design within a retrospective cohort of adult home care patients in Ontario. Results A total of 11,840 home care nursing patients were analyzed. Home care patients who received a home nursing visit were more likely to go the ED after hours on the same day with a stronger association for visits not admitted to the hospital. Having a urinary catheter increased the risk of a same-day ED visit (OR: 1.78 (95% CI 1.15–1.60) vs. 1.21 (95% CI 1.15–1.28)). No other clinical indicator modified the association. The findings of this study can be used to inform care policies and practices for home care nurses in the management of indwelling urinary catheter complications. Further examination of system factors such as capacity and resources available to respond to catheter related complications in the community setting are recommended

Ground Contact Time Imbalances Strongly Related to Impaired Running Economy

Running economy (RE) is defined as the oxygen consumption (VO2) or caloric unit cost required to move at a specific velocity and is an important performance marker. Ground contact time (GCT) has been associated with RE; however, it has not been established how GCT imbalances between feet impact RE. Purpose: Determine the relationship between cadence, GCT, and GCT imbalances and RE. Methods: 11 NCAA Division I distance runners (7 male) completed a graded exercise test on a treadmill to determine lactate threshold (LT) and VO2max. Body composition was also assessed via DEXA. Subjects ran with a heart rate monitor capable of measuring cadence, GCT, and GCT balance between feet. VO2 and respiratory exchange ratio were recorded over the last minute of the 5-minute stages. RE expressed as caloric unit cost (kcal·kg-1· km-1) was calculated for the stage determined to be just below the LT (prior to \u3e 4mmol/L) and was correlated with cadence, GCT, and GCT imbalance by Pearson correlations. Results: Pearson correlations between RE and the running dynamics measures were as follows: cadence (r = -.444, p = .171), GCT (r = .492, p = .125), GCT Imbalance (r = .808, p \u3c .005). An independent t-test revealed greater (p = .023) leg lean mass imbalances in runners with larger GCT imbalances compared to runners with smaller GCT imbalances. Conclusion: GCT imbalances are strongly related to impaired RE. Future research should determine how to improve GCT imbalances and if doing so improves RE

Seasonal cycle in atmospheric HCl at 45 deg S

High resolution Fourier transform infrared interferometric atmospheric solar absorption measurements have been performed at the National Institute for Water and Atmospheric Research Laboratory at Lauder, New Zealand on a routine basis since October 1989. This laboratory has been selected as the Mid-latitude Charter Site of the Network for the Detection of Stratospheric Change and is at a latitude of 45 deg S. Particular attention has been paid to the absorption by atmospheric hydrogen chloride at 2925.9 cm(exp -1) and in this paper the results of the seasonal cycle in CHl above Lauder will be presented. Because of the very clean troposphere at this site, the CHl column measured from the ground is essentially a stratospheric column measurement

Evidence of the Harmonic Faraday Instability in Ultrasonic Atomization Experiments with a Deep, Inviscid Fluid

A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω~MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability driving a capillary wave at the subharmonic (ω/2) frequency. For many applications it is desirable to reduce the size of the droplets; however, using higher frequency oscillators becomes impractical beyond a few MHz. Observations are presented that demonstrate that smaller droplets may also be created by increasing the driving amplitude of the oscillator, and that this effect becomes more pronounced for large driving frequencies. It is shown that these observations are consistent with a transition from droplets associated with subharmonic (ω/2) capillary waves to harmonic (ω) capillary waves induced by larger driving frequencies and amplitudes, as predicted by a stability analysis of the capillary waves

The Vermicelli and Capellini Handling Tests: Simple quantitative measures of dexterous forepaw function in rats and mice

Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended upon this work to develop a simple quantitative measure of forepaw dexterity that is sensitive to lateralized impairments and age-dependent changes. Rodents learn skillful forepaw and digit movements to manage thin pasta pieces, which they eagerly consume. We have previously described methods for quantifying vermicelli handling in rats and showed that the measures are very sensitive to forelimb impairments resulting from unilateral ischemic lesions, middle cerebral artery occlusions and unilateral striatal dopamine depletion [Allred, R.P., Adkins, D.L., Woodlee, M.T., Husbands, L.C., Maldonado M.A., Kane, J.R., Schallert, T. & Jones, T.A. The Vermicelli Handling Test: a simple quantitative measure of dexterous forepaw function in rats. J. Neurosci. Methods 170, 229-244 (2008)]. Here we present a more detailed protocol for this test in rats and compare it with a newly developed version for mice, the Capellini Handling Test. Rats and mice are videotaped while handling short lengths of uncooked vermicelli or capellini pasta, respectively, with a camera positioned to optimize the view of paw movements. Slow motion video playback allows for the identification of forepaw adjustments, defined as any distinct removal and replacement of the paw, or of any number of digits, on the pasta piece after eating commences. Forepaw adjustments per piece are averaged over trials per each testing session. Repeated testing permits sensitive quantitative analysis of changes in forepaw dexterity over time. Protocols for pre-testing habituation and handling practice, as well as procedures for characterizing atypical handling patterns, are described. Because rats and mice perform the pasta handling tests slightly differently, species-specific differences in administration and scoring of these tests are highlighted. All animal use was in accordance with protocols approved by the University of Texas at Austin Animal Care and Use Committee

Erythropoietin Does Not Enhance Skeletal Muscle Protein Synthesis Following Exercise in Young and Older Adults

PURPOSE: Erythropoietin (EPO) is a renal cytokine that is primarily involved in hematopoiesis while also playing a role in non-hematopoietic tissues expressing the EPO-receptor (EPOR). The EPOR is present in human skeletal muscle. In mouse skeletal muscle, EPO stimulation can activate the AKT serine/threonine kinase 1 (AKT) signaling pathway, the main positive regulator of muscle protein synthesis. We hypothesized that a single intravenous EPO injection combined with acute resistance exercise would have a synergistic effect on skeletal muscle protein synthesis via activation of the AKT pathway. METHODS: Ten young (24.2 ± 0.9 years) and 10 older (66.6 ± 1.1 years) healthy subjects received a primed, constant infusion of [ring-13C(6)] L-phenylalanine and a single injection of 10,000 IU epoetin-beta or placebo in a double-blind randomized, cross-over design. 2 h after the injection, the subjects completed an acute bout of leg extension resistance exercise to stimulate skeletal muscle protein synthesis. RESULTS: Significant interaction effects in the phosphorylation levels of the members of the AKT signaling pathway indicated a differential activation of protein synthesis signaling in older subjects when compared to young subjects. However, EPO offered no synergistic effect on vastus lateralis mixed muscle protein synthesis rate in young or older subjects. CONCLUSIONS: Despite its ability to activate the AKT pathway in skeletal muscle, an acute EPO injection had no additive or synergistic effect on the exercise-induced activation of muscle protein synthesis or muscle protein synthesis signaling pathways

Relationship between FEV1 change and patient-reported outcomes in randomised trials of inhaled bronchodilators for stable COPD: a systematic review.

BACKGROUND: Interactions between spirometry and patient-reported outcomes in COPD are not well understood. This systematic review and study-level analysis investigated the relationship between changes in FEV1 and changes in health status with bronchodilator therapy. METHODS: Six databases (to October 2009) were searched to identify studies with long-acting bronchodilator therapy reporting FEV1 and health status, dyspnoea or exacerbations. Mean and standard deviations of treatment effects were extracted for each arm of each study. Relationships between changes in trough FEV1 and outcomes were assessed using correlations and random-effects regression modelling. The primary outcome was St George's Respiratory Questionnaire (SGRQ) total score. RESULTS: Thirty-six studies (≥ 3 months) were included. Twenty-two studies (23,654 patients) with 49 treatment arms each contributing one data point provided SGRQ data. Change in trough FEV1 and change in SGRQ total score were negatively correlated (r = -0.46, p < 0.001); greater increases in FEV1 were associated with greater reductions (improvements) in SGRQ. The correlation strengthened with increasing study duration from 3 to 12 months. Regression modelling indicated that 100 mL increase in FEV1 (change at which patients are more likely to report improvement) was associated with a statistically significant reduction in SGRQ of 2.5 (95% CI 1.9, 3.1), while a clinically relevant SGRQ change (4.0) was associated with 160.6 (95% CI 129.0, 211.6) mL increase in FEV1. The association between change in FEV1 and other patient-reported outcomes was generally weak. CONCLUSIONS: Our analyses indicate, at a study level, that improvement in mean trough FEV1 is associated with proportional improvements in health status