Hyper-arousal decreases human visual thresholds.
TL;DR: Results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds, which has important implications for survival, sports, and everyday life.
Abstract: Arousal has long been known to influence behavior and serves as an underlying component of cognition and consciousness. However, the consequences of hyper-arousal for visual perception remain unclear. The present study evaluates the impact of hyper-arousal on two aspects of visual sensitivity: visual stereoacuity and contrast thresholds. Sixty-eight participants participated in two experiments. Thirty-four participants were randomly divided into two groups in each experiment: Arousal Stimulation or Sham Control. The Arousal Stimulation group underwent a 50-second cold pressor stimulation (immersing the foot in 0–2° C water), a technique known to increase arousal. In contrast, the Sham Control group immersed their foot in room temperature water. Stereoacuity thresholds (Experiment 1) and contrast thresholds (Experiment 2) were measured before and after stimulation. The Arousal Stimulation groups demonstrated significantly lower stereoacuity and contrast thresholds following cold pressor stimulation, whereas the Sham Control groups showed no difference in thresholds. These results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds. Hyper-arousal's ability to decrease visual thresholds has important implications for survival, sports, and everyday life.
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TL;DR: In this article, 105 rainfall simulations were carried out in agriculture lands of the Mediterranean belt in Spain (vineyards in Malaga, almond orchards in Murcia, and orange and olive orchars in Valencia) and in paired abandoned lands to assess the impact of land abandonment on soil and water losses.
85 citations
TL;DR: In this paper, a combined methodology was applied, using soil analysis, a small portable rainfall simulator and a Guelph permeameter on one experimental plot cultivated with vineyards with steep slopes.
Abstract: Conventional Mediterranean vineyards from the Montes de Malaga (Axarquia region, Spain) are characterized by high average temperatures, extreme rainfall events during autumn and winter, elevated stoniness and steep slopes (20–50°). Traditionally, several problems of high soil loss, rill and ephemeral gully generation, and elevated runoff are observed by farmers, which are increasing land degradation processes and a decrease of the productivity. According to this, the main aims of this paper were: i) to quantify the initial soil loss, surface flow and infiltration processes; ii) to characterize and describe the hydrological and geomorphological dynamics; iii) to detect the key factors, which control the soil erosion processes. For this purpose, a combined methodology was applied, using soil analysis, a small portable rainfall simulator and a Guelph permeameter on one experimental plot cultivated with vineyards with steep slopes. Results showed a high variability of soil erosion and permeability processes. Soil analysis showed an elevated concentration of silt particles and stoniness, with higher contents of sand particles between 0 and 5 cm, and clays from 5 cm. With a Guelph permeameter, high average of permeability and saturated hydraulic conductivity with elevated standard deviation were observed. Furthermore, an increase of these parameters from the upper to the foot slope was registered. By using rainfall simulations, on the upper and the foot slope positions the highest runoff coefficient and soil loss were registered. The most elevated peak of sediment concentration was obtained on the middle slope. In general, high infiltration coefficients between 66.5 and 100% were observed. In conclusion it was observed that the activation of the soil erosion processes was due to the distribution of the surface soil components (high roughness, several cracks and high stoniness and silt content), the steep slopes and the impact of the soil traditional tillage practices. These Mediterranean hillslope vineyards registered a mixed Hortonian-Hewlettian model, which combines surface and sub-surface flow conditioned by the micro-topographical changes and its saturation degree.
83 citations
TL;DR: In this article, the authors evaluated two agri-spillways (between 10 m and 15 m length, and slopes between 25.8° and 35°) by performing runoff experiments under extreme conditions (a motor driven pump that discharged water flows up to 1.33 l s-1 for 12 to 15 minutes: ≈1000 l).
Abstract: Suitable vineyard soils enhance soil stability and biodiversity which in turn protects roots against erosion and nutrient losses. There is a lack of information related to inexpensive and suitable methods and tools to protect the soil in Mediterranean sloping vineyards (>25° of slope inclination). In the vineyards of the Montes de Malaga (southern Spain), a sustainable land management practice that controls soil erosion is actually achieved by tilling rills in the down-slope direction to canalize water and sediments. Because of their design and use, we call them agri-spillways. In this research, we assessed two agri-spillways (between 10 m and 15 m length, and slopes between 25.8° and 35°) by performing runoff experiments under extreme conditions (a motor driven pump that discharged water flows up to 1.33 l s-1 for 12 to 15 minutes: ≈1000 l). The final results showed: i) a great capacity by these rills to canalize large amounts of water and sediments; and, ii) higher water flow speeds (between 0.16 m s-1 and 0.28 m s-1) and sediment concentration rates (up to 1538.6 g l-1) than typically found in other Mediterranean areas and land uses (such as badlands, rangelands or extensive crops of olives and almonds). The speed of water flow and the sediment concentration were much higher in the shorter and steeper rill. We concluded that agri-spillways, given correct planning and maintenance, can be a potential solution as an inexpensive method to protect the soil in sloping Mediterranean vineyards.
42 citations
TL;DR: Lesmes et al. as discussed by the authors measured the full contrast sensitivity function as a function of emotional arousal in order to investigate potential interactions between spatial frequency and contrast, and used a Bayesian adaptive inference with a trial-to-trial information gain strategy and a fear-conditioned stimulus to manipulate arousal level.
Abstract: Recent evidence indicates that emotion enhances contrast thresholds in subsequent visual perception (Phelps, Ling, & Carrasco, 2006) and perceptual sensitivity for low-spatial frequency but not high-spatial frequency targets (Bocanegra & Zeelenberg, 2009b). However, these studies just report responses to various frequencies at a fixed contrast level or responses to various contrasts at a fixed frequency. In the current study, we measured the full contrast sensitivity function as a function of emotional arousal in order to investigate potential interactions between spatial frequency and contrast. We used a Bayesian adaptive inference with a trial-to-trial information gain strategy (Lesmes, Lu, Baek, & Albright, 2010) and a fear-conditioned stimulus to manipulate arousal level. The spatial frequency at which people showed peak contrast sensitivity shifted to lower spatial frequencies in the arousing condition compared with the nonarousing condition and people had greater contrast sensitivity function bandwidth in the arousing than in the nonarousing condition.
41 citations
TL;DR: This study demonstrates that summary statistics imputation is a very efficient and cost-effective way to identify and fine-map trait-associated loci and test its capacity to discover novel associations.
Abstract: As most of the heritability of complex traits is attributed to common and low frequency genetic variants, imputing them by combining genotyping chips and large sequenced reference panels is the most cost-effective approach to discover the genetic basis of these traits. Association summary statistics from genome-wide meta-analyses are available for hundreds of traits. Updating these to ever-increasing reference panels is very cumbersome as it requires reimputation of the genetic data, rerunning the association scan, and meta-analysing the results. A much more efficient method is to directly impute the summary statistics, termed as summary statistics imputation, which we improved to accommodate variable sample size across SNVs. Its performance relative to genotype imputation and practical utility has not yet been fully investigated. To this end, we compared the two approaches on real (genotyped and imputed) data from 120K samples from the UK Biobank and show that, genotype imputation boasts a 3- to 5-fold lower root-mean-square error, and better distinguishes true associations from null ones: We observed the largest differences in power for variants with low minor allele frequency and low imputation quality. For fixed false positive rates of 0.001, 0.01, 0.05, using summary statistics imputation yielded a decrease in statistical power by 9, 43 and 35%, respectively. To test its capacity to discover novel associations, we applied summary statistics imputation to the GIANT height meta-analysis summary statistics covering HapMap variants, and identified 34 novel loci, 19 of which replicated using data in the UK Biobank. Additionally, we successfully replicated 55 out of the 111 variants published in an exome chip study. Our study demonstrates that summary statistics imputation is a very efficient and cost-effective way to identify and fine-map trait-associated loci. Moreover, the ability to impute summary statistics is important for follow-up analyses, such as Mendelian randomisation or LD-score regression.
41 citations
References
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TL;DR: A functional model is proposed based on known neuroanatomical and neurophysiological findings and it is suggested that, when neurological or psychiatric disorders manifest symptoms related to arousal and sleep-wake control, disturbances of elements of the reticular activating system must be considered responsible.
105 citations
"Hyper-arousal decreases human visua..." refers background in this paper
...[4–11] In most domains of vision science, however, arousal is not incorporated into theoretical models....
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TL;DR: The aim of the present study was to determine the brain sites mediating aspects of respiratory and cardiovascular control in adult humans using non‐invasive functional magnetic resonance (/MRI) procedures, thereby avoiding the spatial and temporal sampling limitations associated with classic neural assessment techniques.
Abstract: SUMMARY
1. The aim of the present study was to determine the brain sites mediating aspects of respiratory and cardiovascular control in adult humans using non-invasive functional magnetic resonance (/MRI) procedures, thereby avoiding the spatial and temporal sampling limitations associated with classic neural assessment techniques.
2. We examined activity changes across the entire brain following application of respiratory loads and upon induction of blood pressure and heart rate alterations. Magnetic resonance signals were visualized with a 1.5Tesla scanner in healthy volunteers (22-52 years of age) using procedures that optimally assess changes in brain tissue microcirculation. Images were collected during a Valsalva manoeuvre, inspiratory loading, hypercapnia, cold pressor challenges to the hand and forehead and during intervening baseline states.
3. Image values from experimental conditions were compared with corresponding baseline values on a pixel-by-pixel basis to identify brain regions in which the experimental conditions produced physiological activation.
4. Ventilatory and pressor challenges elicited significant changes in regional image signal intensity in areas within the orbital cortex, amygdala, hypothalamus and hippocampus. Cerebellar, medullary and pontine areas were also recruited. However, while particular brain regions were only activated during specific stimuli, other regional signal changes occurred with multiple experimental manipulations.
5. The findings indicate that respiratory and cardiac challenges elicit discrete activity changes over multiple brain sites. Activated regions include structures not often related to respiratory or cardiovascular regulation, such as the cerebellum; a prominent role for limbic forebrain structures in mediating the response is also suggested. The f MRI visualization procedures may greatly assist in the determination of neural structures that mediate respiratory and cardiovascular control in humans.
101 citations
TL;DR: Cardiovascular autonomic function is impaired long after the index event in stroke survivors, and this may increase the risk of all-cause mortality and cardiovascular mortality in older stroke survivors.
Abstract: Background and Purpose— Impaired autonomic function is common in the acute poststroke phase but little is known about the longer term effects, particularly in older people. We sought to determine if autonomic function is impaired after stroke recovery in older patients. Methods— A cross-sectional case-control study comparing autonomic function in 76 nondemented stroke patients with 70 community-living controls aged older than 75 years. Results— Cases were assessed on average 9 months after stroke. From power spectral analysis of heart rate variability, stroke patients had lower total (P=0.032) and low-frequency (P=0.014) spectral densities and impaired baroreflex sensitivity (α low-frequency baroreflex sensitivity, P=0.006). From a series of cardiovascular autonomic reflex tests, heart rate variation during forced respiration, Valsalva ratio, and blood pressure overshoot during Valsalva maneuver were significantly lower in stroke patients (P=0.003, <0.001, and 0.027, respectively). Blood pressure response...
98 citations
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TL;DR: Different branches of the same axon, with different innervation patterns, display branch type-specific motility in the adult cerebellum and dynamic changes in transverse branch length were almost completely suppressed by pharmacological stimulation of olivary firing.
89 citations
TL;DR: The cold-pressor test diminished P50 auditory gating in nine subjects, although the degree of impairment was highly variable among subjects, and the impairment was transient.
88 citations