Search results for "physiologic"
showing 10 items of 2593 documents
A comparison of the cheater detection and the unrelated question models: a randomized response survey on physical and cognitive doping in recreationa…
2016
PURPOSE:This study assessed the prevalence of physical and cognitive doping in recreational triathletes with two different randomized response models, that is, the Cheater Detection Model (CDM) and the Unrelated Question Model (UQM). Since both models have been employed in assessing doping, the major objective of this study was to investigate whether the estimates of these two models converge. MATERIAL AND METHODS:An anonymous questionnaire was distributed to 2,967 athletes at two triathlon events (Frankfurt and Wiesbaden, Germany). Doping behavior was assessed either with the CDM (Frankfurt sample, one Wiesbaden subsample) or the UQM (one Wiesbaden subsample). A generalized likelihood-rati…
Enhancement of human cortico-motoneuronal excitability by the selective norepinephrine reuptake inhibitor reboxetine
2002
It has been proposed that norepinephrine plays a critical role in the modulation of cortical excitability, which in turn is thought to influence functional recovery from brain lesions. The purpose of the present experiments was to determine if it is possible to modulate cortical excitability with the selective norepinephrine reuptake inhibitor reboxetine in intact humans. Recruitment curve and intracortical facilitation, assessed by transcranial magnetic stimulation, were increased after oral intake of 8 and 4 mg reboxetine, in the absence of changes in motor threshold, intracortical inhibition, M-response, F-wave or H-reflex. These results demonstrate that reboxetine enhances cortical exci…
Motor recruitment during action observation: Effect of interindividual differences in action strategy
2020
Abstract Visual processing of other’s actions is supported by sensorimotor brain activations. Access to sensorimotor representations may, in principle, provide the top-down signal required to bias search and selection of critical visual features. For this to happen, it is necessary that a stable one-to-one mapping exists between observed kinematics and underlying motor commands. However, due to the inherent redundancy of the human musculoskeletal system, this is hardly the case for multijoint actions where everyone has his own moving style (individual motor signature—IMS). Here, we investigated the influence of subject’s IMS on subjects’ motor excitability during the observation of an actor…
Does the Recruitment of Excitation and Inhibition in the Motor Cortex Differ?
2007
The level of excitability within the motor cortex can be described as a balance between excitation and inhibition, but it is unknown how well both processes correlate. To address this question, the authors measured motor cortical excitability and inhibition in healthy human subjects, comparing the recruitment of motor evoked potentials (MEPs) and the duration of the cortical silent period (CSP) after transcranial magnetic stimulation (TMS). Single-pulse "focal" TMS was applied at intensities varying between 90% and 200% of motor thresholds to the right motor cortex of 15 healthy volunteers. The peak-to peak size of MEP responses and the duration of the CSP were measured in small hand muscle…
Effects of effort and EMG levels on short-latency stretch reflex modulation after varying background muscle contractions.
2005
It is known that the short-latency stretch reflex (SLSR) is modulated by the background muscle activity when it is elicited at matched torque levels. This study was designed to examine the effects of muscle contraction types before a stretch perturbation on SLSR in the human soleus muscle (SOL) when SLSR was elicited at the same levels of effort and at matched electromyographic (EMG) activity levels. A mechanical stretch perturbation was applied to the calf muscles when the ankle joint reached a ninety degree tibio-tarsal joint angle after the muscles performed an isometric (pre-ISO), shortening (pre-SHO) and lengthening contraction (pre-LEN). Subjects were seated on an ankle ergometer chai…
The effects of muscle history on short latency stretch reflex response of soleus muscle
2003
Abstract The purpose of the present study was to investigate the combined effects of muscle history, activation and stretching velocity on short latency stretch response (SLR). Stretches (70, 120 and 200 deg s-1) were elicited to both passive and active (10–25% MVC) triceps surae muscle with constant (ISO), lengthened (LEN) or shortened (SHO) muscle length. Under the passive SHO pre-condition both SLR amplitude and reflex torque (RT) decreased where as latency increased compared with the passive ISO pre-condition. Such observations were absent in active trials. Stretches applied to a lengthening passive muscle (LEN) resulted in smaller SLR amplitude and RT compared with passive ISO. In acti…
Psychophysiological differentiation of deception: the effects of electrodermal lability and mode of responding on skin conductance and heart rate
2001
The differentiation-of-deception paradigm enables the examination of deception as a psychophysiological process by varying, within subjects, two conditions which differ only with respect to honesty and deception. The present experiment assessed the effects of two group factors - electrodermal lability and mode of responding - on the deception phenomenon in a situation with low emotional involvement and mental load. Skin conductance responses, phasic heart rate, self-rated relaxation, calmness, and concentration were the dependent variables. Twenty questions referring to general knowledge were presented on a monitor. The 88 male participants answered half of the questions deceptively and the…
Physiological responses and parasympathetic reactivation in rescue interventions: The effect of the breathing apparatus.
2018
This study aimed to assess the effect of wearing a breathing apparatus during a simulated rescue intervention on psychophysiological responses and parasympathetic reactivation of firefighters. Thirty-four firefighters participated in this study which consisted of four experimental sessions conducted randomly: a maximal fitness test and three rescue interventions performed (a) with personal protective clothing (PPC); (b) with PPC and the full self-contained breathing apparatus (SCBA), including cylinder, full-face piece, and breathing regulator; and (c) with PPC and only the cylinder of the self-contained breathing apparatus (SCBAc). Physiological (heart rate [HR], breathing frequency [BF]) …
Impact of antenatal glucocorticoid therapy and risk of preterm delivery on intelligence in term-born children
2015
Context: Women at risk of preterm delivery are routinely treated with synthetic glucocorticoids (sGCs). Although this therapy substantially reduces neonatal morbidity, concerns remain whether sGC excess may disrupt neurodevelopmental trajectories underlying cognitive functioning. Objective: The present study is the first to disentangle direct effects of antenatal sGC treatment on possible long-term cognitive disadvantages from those of pregnancy complications and prematurity. Design, Setting, and Participants: This cross-sectional study included a mixed-sex cohort of 222 term-born children (aged 6–11 years) consisting of three groups: children of mothers admitted to hospital for threatening…
Development of a New Nordic Diet score and its association with gestational weight gain and fetal growth - A study performed in the Norwegian Mother …
2014
AbstractObjectiveTo construct a diet score for assessing degree of adherence to a healthy and environmentally friendly New Nordic Diet (NND) and to investigate its association with adequacy of gestational weight gain and fetal growth in a large prospective birth cohort.DesignMain exposure was NND adherence, categorized as low, medium or high adherence. Main outcomes were adequacy of gestational weight gain, described as inadequate, optimal or excessive according to the 2009 Institute of Medicine guidelines, and fetal growth, categorized as being small, appropriate or large for gestational age. Associations of NND adherence with gestational weight gain and fetal growth were estimated with mu…