Orthographic and phonological processing in developing readers revealed by ERPs

Abstract

The development of neurocognitive mechanisms in single word reading was studied in children ages 8–10 years using ERPs combined with priming manipulations aimed at dissociating orthographic and phonological processes. Transposed-letter (TL) priming (barin–BRAIN vs. bosin–BRAIN) was used to assess orthographic processing, and pseudohomophone (PH) priming (brane–BRAIN vs. brant–BRAIN) was used to assess phonological processing. Children showed TL and PH priming effects on both the N250 and N400 ERP components, and the magnitude of TL priming correlated positively with reading ability, with better readers showing larger TL priming effects. Phonological priming, on the other hand, did not correlate with reading ability. The positive correlations between TL priming and reading ability in children points to a key role for flexible sublexical orthographic representations in reading development, in line with their hypothesized role in the efficient mapping of orthographic information onto semantic information in skilled readers.

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Pupillary reactivity to negative stimuli prospectively predicts recurrence of major depressive disorder in women

Abstract

There is a large body of research supporting the association between disrupted physiological reactivity to negative stimuli and depression. The present study aimed to examine whether physiological reactivity to emotional stimuli, assessed via pupil dilation, served as a biological marker of risk for depression recurrence among individuals who are known to be at a higher risk due to having previous history of depression. Participants were 57 women with a history of major depressive disorder (MDD). Pupil dilation to angry, happy, sad, and neutral faces was recorded. Participants' diagnoses and symptoms were assessed 24 months after the initial assessment. We found that women's pupillary reactivity to negative (sad or angry faces) but not positive stimuli prospectively predicted MDD recurrence. Additionally, we found that both hyper- and hypopupillary reactivity to angry faces predicted risk for MDD recurrence. These findings suggest that disrupted physiological response to negative stimuli indexed via pupillary dilation could serve as a physiological marker of MDD risk, thus presenting clinicians with a convenient and inexpensive method to predict which of the at-risk women are more likely to experience depression recurrence.

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Spinal Cord Injury Level Influences Acute Plasma Caffeine Responses.

Purpose: To investigate the absorption curve and acute effects of caffeine at rest in individuals with no spinal cord injury (SCI), paraplegia (PARA) and tetraplegia (TETRA). Methods: Twenty-four healthy males (8 able-bodied (AB), 8 PARA and 8 TETRA) consumed 3 mg[BULLET OPERATOR]kg-1 caffeine anhydrous (CAF) in a fasted state. Plasma caffeine [CAF], glucose, lactate, free-fatty acid [FFA] and catecholamine concentrations were measured during a 150 min rest period. Results: Peak [CAF] was greater in TETRA (21.5 [mu]M) compared to AB (12.2 [mu]M) and PARA (15.1 [mu]M), and mean peak [CAF] occurred at 70, 80 and 80 min, respectively. Moderate and large ES were revealed for TETRA compared to PARA and AB (-0.55 and -1.14, respectively) for the total area under the [CAF] versus time curve. Large inter-individual responses were apparent in SCI groups. The change in plasma catecholamine concentrations following CAF did not reach significance (p>0.05) however both adrenaline and noradrenaline concentrations were lowest in TETRA. Significant increases in [FFA] were seen over time (p0.05). Conclusion: Level of SCI influenced the caffeine absorption curve and there was large inter-individual variation within and between groups. Individual curves should be considered when using caffeine as an ergogenic aid in athletes with an SCI. The results indicate TETRA should trial low doses in training and PARA may consider consuming caffeine greater than 60 min prior to exercise performance. The study also supports caffeine's direct effect on adipose tissue, which is not secondary to catecholamine release. (C) 2016 American College of Sports Medicine

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The Impact of a Healthy Lifestyle on Future Physical Functioning in Midlife Women.

Purpose: To examine the prospective association between healthy lifestyle behaviors and objectively measured physical function in midlife women. Methods: Participants included 1,769 racially/ethnically diverse women, ages 56-68, from the SWAN (Study of Women's Health Across the Nation) cohort. Physical function was assessed at the 13th follow-up (FU13) visit with the Short Physical Performance Battery (4 meter walk, repeated chair stands, and balance test) and grip strength. A Healthy Lifestyle Score (HLS), which ranged from 0-6, was calculated by averaging as many as three repeated measures of self-reported smoking, physical activity, and diet, all assessed prior to FU13. Multivariable linear and logistic regressions modeled each component of physical performance as a function of HLS and, in separate models, of each lifestyle behavior, adjusted for the other behaviors. Results: In multivariable analyses, the time for the 4 M walk was 0.06 secs faster (p=0.001) for every 1 point increase in the HLS. The time for the repeated chair stands was significantly shorter by about 0.20 seconds. Neither grip strength nor balance problems were significantly associated with the HLS (p=.28, p=0.19 respectively). The model examining the individual health behaviors showed that only physical activity was significantly associated with physical performance. Conclusion: Regular physical activity in early midlife has the potential to reduce the likelihood of physical functional limitations later in midlife. (C) 2016 American College of Sports Medicine

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Triathletes Lose Their Advantageous Pain Modulation under Acute Psychosocial Stress.

Introduction: Triathletes, who constantly engage in intensely stressful sport, were recently found to exhibit greater pain tolerance and more efficient pain inhibition capabilities than non athletes. However, pain inhibition correlated negatively with retrospective reports of mental stress during training and competition. The aim of the current study was to test pain inhibition capabilities of triathletes under acute, controlled psychological stress manipulation. Methods: Participants were 25 triathletes and ironman triathletes who underwent the measurement of pain-threshold, pain-intolerance, tonic suprathreshold pain and conditioned pain modulation (CPM) before and during exposure to the Montreal Imaging Stress Task (MIST). Perceived ratings of stress and anxiety, autonomic variables and salivary cortisol levels were obtained as indices of stress. Results: The MIST induced a significant stress reaction manifested in the subjective and objective indices. Overall, a significant reduction in pain threshold and in CPM efficacy was observed following the MIST, which reached the baseline levels observed previously in non-athletes. Paradoxically, the magnitude of this stress-induced hyperalgesia (SIH) correlated negatively with the magnitude of the stress response; low stress-responders exhibited greater SIH than high stress-responders. Conclusion: The results suggest that under acute psychological stress, triathletes not only react with SIH and a reduction in pain modulation, but also lose their advantageous pain modulation over non-athletes. The stronger the stress response recorded, the weaker the SIH. It appears that triathletes are not resilient to stress, responding with an increase in the sensitivity to pain as well as a decrease in pain inhibition. The possible effects of athletes' baseline pain profile and stress reactivity on SIH are discussed. (C) 2016 American College of Sports Medicine

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Metabolic Responses to the Yukon Arctic Ultra: Longest and Coldest in the World.

PURPOSE: The Yukon Arctic Ultra is considered the longest and coldest ultraendurance event in the world. Cold exposure and exercise has been reported to influence circulating levels of myo-, adipo- and hepato-kines that may influence considerable alterations in the regulation of metabolism. The purpose of the study was to evaluate the influence of the Yukon Arctic Ultra (430 mile event) on potential activators of brown fat, metabolites and body composition in healthy individuals. METHODS: Eight male and female participants (mean+/-SEM; age = 44+/-3 yr; BMI = 23.4+/-0.9) were recruited for participation. Blood samples were collected at pre-event, mid event and post-event checkpoints. RESULTS: The temperature during the event ranged from -45[degrees]C to -8[degrees]C. Due to these extremely challenging conditions, 50% of the participants withdrew from competition by the 300 mile mark, and those that surpassed 300 miles lost a significant (p=0.002; p=0.01) amount of body weight (76+/-5 kg to 73+/-4 kg) and fat mass (13+/-1 kg to 12+/-3 kg), respectively. With respect to serum irisin, there was a trend (p=0.06) towards significance from pre-event (1033+/-88 ng/ml), mid-event (1265+/-23 ng/ml) to post-event (1289+/-24 ng/ml). Serum meteorin and fibroblast growth factor-21 remained stable throughout the event. There were no changes in creatinine, acetoacetate, acetate, and valine. Serum lactate decreased (p=0.04) during the event. CONCLUSION: The influence of cold exposure and extreme physical exertion may promote substantial increases in serum irisin, and specific alterations in substrate metabolism that largely preserve skeletal muscle and physiological resilience. (C) 2016 American College of Sports Medicine

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High-Intensity Interval Training Increases Cardiac Output and VO2max.

Increases in maximal oxygen uptake (VO2max) frequently occur with high-intensity interval training (HIIT), yet the specific adaptation explaining this result remains elusive. PURPOSE: This study examined changes in VO2max and cardiac output (CO) in response to periodized HIIT. METHODS: Thirty nine active men and women (mean age and VO2max = 22.9 +/- 5.4 yr and 39.6 +/- 5.6 mL/kg/min) performed HIIT and 32 men and women (age and VO2max = 25.7 +/- 4.5 yr and 40.7 +/- 5.2 mL/kg/min) were non-exercising controls (CON). The first 10 sessions of HIIT required eight to ten 60 s bouts of cycling at 90 - 110 percent peak power output (PPO) interspersed with 75 s recovery, followed by randomization to one of three regimes (sprint interval training (SIT), high-volume interval training (HIITHI), or periodized interval training (PER) for the subsequent 10 sessions. Before, midway, and at the end of training, progressive cycling to exhaustion was completed during which VO2max and maximal CO (COmax) were estimated. RESULTS: Compared to CON, significant (p

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