Search results for "Differential Threshold"
showing 10 items of 14 documents
Modulatory effects of 1 Hz rTMS over the cerebellum on motor cortex excitability
2005
Clinical observations and data from animal experiments point to a physiological facilitatory influence of the deep cerebellar structures on the motor system through the cerebello-thalamo-cortical pathways. The aim of the present study was to explore the long-term effects of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over the cerebellum on short intracortical inhibition (SICI) and facilitation (ICF) of the motor cortex in normal subjects. Eight healthy subjects (mean age 26.9 +/- 3.1) underwent 1 Hz frequency rTMS delivered on the right cerebellar hemisphere. Before and after cerebellar rTMS, SICI and ICF were assessed in the motor cortex contralateral to the st…
Mechanical work and efficiency in treadmill running at aerobic and anaerobic thresholds
1990
Mechanical work, mechanical power, energy consumption and mechanical efficiency were studied in constant-speed treadmill running of 5 min at seven different exercises around aerobic (AerT) and anaerobic (AnT) thresholds. The true efficiency of concentric (positive) mechanical work and gross efficiency of the whole body in seven male subjects were calculated. The total mechanical work was calculated from film through the translational, potential and rotational energy states as the sum of the changes of all the mechanical energy states in all body segments allowing energy transfer between segments and from energy state to state. The total energy consumption was measured by combining aerobic a…
Reproducibility of aerobic and anaerobic thresholds in 20-50 year old men.
1984
The reproducibility of the aerobic (AerT) and the anaerobic (AnT) threshold was studied in 33 men aged 20–50 years. They completed two maximal exercise tests on a bicycle ergometer. The thresholds, as $$\dot V_{O_2 }$$ (l·min−1), were determined visually by two investigators using both the blood lactate and the respiratory indices. The respiratory variables were measured with a computerized breath-by-breath method; samples of venous blood were drawn every 2nd min and analysed enzymatically for lactate. The reproducibility of the AerT (r=0.94) and of the AnT (r=0.96) were equally good. The AnT can be determined either from blood lactate concentrations (AnTLa) or from ventilatory and gas exch…
Muscle metabolic profile and oxygen transport capacity as determinants of aerobic and anaerobic thresholds
1988
Aerobic and anaerobic thresholds determined by different methods in repeated exercise tests were correlated with cardiorespiratory variables and variables of muscle metabolic profile in 33 men aged 20–50 years. Aerobic threshold was determined from blood lactate, ventilation, and respiratory gas exchange by two methods (AerT1 and AerT2) and anaerobic threshold from venous lactate (AnTLa), from ventilation and gas exchange (AnTr) and by using the criterion of 4 mmol·l−1 of venous lactate (AnT4mmol). In addition to ordinary correlative analyses, applications of LISREL models were used. The 8 explanatory variables chosen for the regression analyses were height, relative heart volume, relative …
Neural correlates of antinociception in borderline personality disorder.
2006
Context A characteristic feature of borderline personality disorder (BPD) is self-injurious behavior in conjunction with stress-induced reduction of pain perception. Reduced pain sensitivity has been experimentally confirmed in patients with BPD, but the neural correlates of antinociceptive mechanisms in BPD are unknown. We predicted that heat stimuli in patients with BPD would activate brain areas concerned with cognitive and emotional evaluation of pain. Objective To assess the psychophysical properties and neural correlates of altered pain processing in patients with BPD. Design Case-control study. Setting A university hospital. Participants Twelve women with BPD and self-injurious behav…
Effect of changing pulse rate on profile parameters of perceptual thresholds and loudness comfort levels and relation to ECAP thresholds in recipient…
2010
Abstract: The Nucleus CI24RE Freedom device offers higher stimulation rates and lower noise levels in action potential measurements (ECAPs) than previous devices. A study including ten European implant teams showed that the effect of changes in rate from 250 to 3500 pulses per second on tilt and curvature of the T and C profiles is insignificant. When changing rate one may change the levels at all electrodes by the same amount. Using an automated procedure ECAPs could be measured quickly and reliably at a noise level of only 1 μV. However, this did not result in improved correlations between the tilt and curvature parameters of the ECAP profiles and those of the T and C profiles. Average C …
Carbohydrate ingestion does not influence the change in energy cost during a 2-h run in well-trained triathletes
1999
The aim of this study was to examine whether the increase in the energy cost of running (C(r)), previously reported to occur at the end of a prolonged run, could be influenced by the ingestion of either an artificially sweetened placebo (Pl) or a 5.5% carbohydrate (CHO) solution. Ten well-trained triathletes completed three testing sessions within a 3-week period. The aim of the first session was to determine maximal oxygen uptake (VO(2)(max)) and the velocity associated with ventilatory threshold (nu(VT)). The second and the third sessions were composed of two submaximal treadmill runs (20 min long, 0% grade, performed at nu(VT)), before and after an 80-min overground run, also conducted a…
An automatic test for frequency discrimination
1987
Békésy audiometry has been applied to the determination of the frequency discrimination threshold. The automatic test for frequency discrimination is performed by means of a modified automatic audiometer at fixed frequencies, each administered for a duration of 60 s. The test involves the stimulus of a series of pairs of tone bursts of 500 ms duration: the frequency of one of the tone bursts (f0) is constant, while the other (f0 + delta f) gradually increases and decreases according to the subject's response. The tracings obtained facilitate the evaluation of the discrimination capability of the subject. The pattern obtained from a sample of normally hearing people was analysed in order to …
Changes in intracortical circuits of the human motor cortex following theta burst stimulation of the lateral cerebellum
2008
Objective: The cerebellum takes part in several motor functions through its influence on the motor cortex (M1). Here, we applied the theta burst stimulation (TBS) protocol, a novel form of repetitive Transcranial Magnetic Stimulation (rTMS) over the lateral cerebellum. The aim of this study was to test whether TBS of the lateral cerebellum could be able to modulate the excitability of the contralateral M1 in healthy subjects. Methods: Motor-evoked potentials (MEPs) amplitude, short intracortical inhibition (SICI), long intracortical inhibition (LICI) and short intracortical facilitation (SICF) were tested in the M1 before and after cerebellar continuous TBS (cTBS) or intermittent TBS (iTBS)…
Integration of acoustical information in the perception of impacted sound sources. The role of information accuracy and exploitability.
2010
Sound sources are perceived by integrating information from multiple acoustical features. The factors influencing the integration of information are largely unknown. We measured how the perceptual weighting of different features varies with the accuracy of information and with a listener’s ability to exploit it. Participants judged the hardness of two objects whose interaction generates an impact sound: a hammer and a sounding object. In a first discrimination experiment, trained listeners focused on the most accurate information, although with greater difficulty when perceiving the hammer. We inferred a limited exploitability for the most accurate hammer-hardness information. In a second r…