ABSTRACT
Brain-derived neurotrophic factor (BDNF) and cortisol are both capable of modulating synaptic plasticity, but it is unknown how physical activity-induced changes in their plasma levels relate to corticospinal plasticity in humans. Sixteen inactive middle-aged men and women participated in three separate interventions consisting of 3 h prolonged sitting (SIT); 3 h sitting interrupted every 30 min with frequent short physical activity breaks (FPA); and 2.5 h prolonged sitting followed by 25 min of moderate intensity exercise (EXE). These 3 h sessions were each followed by a 30 min period of paired associative stimulation over the primary motor cortex (PAS). Blood samples were taken and corticospinal excitability measured at baseline, pre PAS, 5 min and 30 min post PAS. Here we report levels of plasma BDNF and cortisol over three activity conditions and relate these levels to previously published changes in corticospinal excitability of a non-activated thumb muscle. There was no interaction between time and condition in BDNF, but cortisol levels were significantly higher after EXE compared to after SIT and FPA. Higher cortisol levels at pre PAS predicted larger increases in corticospinal excitability from baseline to all subsequent time points in the FPA condition only, while levels of BDNF at pre PAS did not predict such changes in any of the conditions. Neither BDNF nor cortisol modified changes from pre PAS to the subsequent time points, suggesting that the increased corticospinal excitability was not mediated though an augmented effect of the PAS protocol. The relationship between cortisol and plasticity has been suggested to be inverted U-shaped. This is possibly why the moderately high levels of cortisol seen in the FPA condition were positively associated with changes AURC, while the higher cortisol levels seen after EXE were not. A better understanding of the mechanisms for how feasible physical activity breaks affect neuroplasticity can inform the theoretical framework for how work environments and schedules should be designed.
Subject(s)
Brain-Derived Neurotrophic Factor , Hydrocortisone , Evoked Potentials, Motor/physiology , Exercise/physiology , Female , Humans , Male , Middle Aged , Neuronal Plasticity/physiology , Transcranial Magnetic Stimulation/methodsABSTRACT
High loads of human papillomavirus (HPV) 16 and HPV 18/45 increase the risk of developing invasive cervical carcinoma, revealing higher risk in percentiles of highest viral loads for HPV 16 (odds ratio (OR) 58.7, 95% confidence interval (CI) 21.9-151.4) compared to HPV 18/45 (OR 3.3, 95% CI 1.5-7.2). Thus, HPV load is a type-dependent risk marker for invasive carcinoma.
Subject(s)
Papillomaviridae/isolation & purification , Uterine Cervical Neoplasms/pathology , Viral Load , Adult , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/virology , DNA, Neoplasm/genetics , Female , Humans , Middle Aged , Neoplasm Invasiveness , Odds Ratio , Risk Factors , Uterine Cervical Neoplasms/virology , Vaginal SmearsABSTRACT
Two experiments examined the lexical properties of the word representations of the Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 1983) stimuli and whether these properties differentially influenced performance of young and older adults in a speeded word naming task and a lexical decision task. The lexical properties of the word representations examined were familiarity, number of letters, frequency of the word's occurrence, and number of syllables. The results of Experiment 1 indicated that the process of lexical access was similar in young and older adults and provided the first examination of lexical properties of the BNT stimuli in a speeded naming situation. The purpose of Experiment 2 was to reexamine the questions raised in Experiment 1 using a lexical decision task. The results of the analysis in Experiment 2 indicated that age was a significant predictor of performance on the lexical decision task. None of the other predictors contributed significantly to the regression equation.
Subject(s)
Aging/psychology , Decision Making/physiology , Language , Memory/physiology , Neuropsychological Tests , Adult , Aged , Education , Female , Humans , Male , Photic Stimulation , Regression Analysis , Vocabulary , Wechsler ScalesSubject(s)
Advertising , Internet , Liability, Legal , Marketing of Health Services/legislation & jurisprudence , Product Labeling/legislation & jurisprudence , Consumer Product Safety , Humans , Information Services/legislation & jurisprudence , Marketing of Health Services/standards , United States , United States Food and Drug AdministrationSubject(s)
Acquired Immunodeficiency Syndrome/prevention & control , Cross Infection/prevention & control , Microsurgery/instrumentation , Operating Room Nursing/methods , Acquired Immunodeficiency Syndrome/transmission , Cross Infection/transmission , Decontamination/methods , Humans , Sterilization/methodsABSTRACT
PIP: The author develops the hypothesis that high levels of fertility in developing countries are the result of deliberate choices by individual couples in response to perceived advantages. The emphasis is on the demand for labor in agrarian societies and on the impact on fertility of colonially imposed economic systems.^ieng
