Search results for "imulation"
showing 10 items of 7271 documents
Speeding up gait initiation and gait-pattern with a startling stimulus.
2008
Human gait involves a repetitive leg motor pattern that emerges after gait initiation. While the automatic maintenance of the gait-pattern may be under the control of subcortical motor centres, gait initiation requires the voluntary launching of a different motor program. In this study, we sought to examine how the two motor programmes respond to an experimental manipulation of the timing of gait initiation. Subjects were instructed to start walking as soon as possible at the perception of an imperative signal (IS) that, in some interspersed trials was accompanied by a startling auditory stimulus (SAS). This method is known to shorten the latency for execution of the motor task under prepar…
Effect of a simulation-based workshop on multidisplinary teamwork of newborn emergencies: an intervention study
2015
Background: Video analyses of real-life newborn resuscitations have shown that Neonatal Resuscitation Program (NRP) guidelines are followed in fewer than 50 % of cases. Multidisciplinary simulation is used as a first-rate tool for the improvement of teamwork among health professionals. In the study we evaluated the impact of the crisis resource management (CRM) and anesthesia non-technical skills instruction on teamwork during simulated newborn emergencies. Methods: Ninety-nine participants of two delivery units (17 pediatricians, 16 anesthesiologists, 14 obstetricians, 31 midwives, and 21 neonatal nurses) were divided to an intervention group (I-group, 9 teams) and a control group (C-group…
Mismatch negativity during objective and subjective sleepiness.
1997
The mismatch negativity (MMN) and P3 of auditory event-related potentials were studied during subjectively and objectively (physiologically) defined sleepiness under optimal stimulus conditions for MMN elicitation. The MMN and P3 were elicited by either small or large unattended auditory deviants presented to the left ear. The participant's task was to detect either rare auditory targets presented to the right ear or rare changes in the light flashes. Eleven young adults served as participants in a nighttime experiment. The MMN declined especially at Fz and Cz but not so markedly at the right mastoid as either subjective or objective alertness decreased. The amplitude of P3 also decreased d…
Assessing Causality in normal and impaired short-term cardiovascular regulation via nonlinear prediction methods
2009
We investigated the ability of mutual nonlinear prediction methods to assess causal interactions in short-term cardiovascular variability during normal and impaired conditions. Directional interactions between heart period (RR interval of the ECG) and systolic arterial pressure (SAP) short-term variability series were quantified as the cross-predictability (CP) of one series given the other, and as the predictability improvement (PI) yielded by the inclusion of samples of one series into the prediction of the other series. Nonlinear prediction was performed through global approximation (GA), approximation with locally constant models (LA0) and approximation with locally linear models (LA1) …
Brain reacts to occasional changes in duration of elements in a continuous sound
1995
In order to study the event-related potential correlates of human ability to detect temporal changes within a continuous sound a sound consisting of two alternating pitches of the same constant duration, with infrequent shortenings of one of the tones, was presented to the subjects. The infrequent shortenings were found to elicit a negative component of the auditory event related potential, called the mismatch negativity (MMN). The experimental parameters were chosen to produce a MMN with a minimal contamination of N1, the main negative deflection of an evoked response with the same latency range as MMN and with a short experimental time. The duration of the whole experiment with three diff…
Antral follicle count (AFC) can be used in the prediction of ovarian response but cannot predict the oocyte/embryo quality or the in vitro fertilizat…
2007
To verify whether the antral follicle count (AFC) could predict ovarian response, oocyte/embryo quality, and IVF outcome.Prospective study.Instituto Universitario-Instituto Valenciano de Infertilidad, Valencia, Spain.One thousand seventy-four donors and 975 oocyte recipient cycles.Controlled ovarian hyperstimulation (COH), endometrial preparation, IVF/intracytoplasmic sperm injection, ET.COH and oocyte/embryo quality parameters and IVF outcome.We observed lower E(2) levels and fewer mature retrieved oocyte numbers among donors who showed an AFC that was10. These donors also showed significantly higher cancellation and no-donation rates; poor and/or insufficient response was the principal ca…
Cortical stimulation and reflex excitability of spinal cord neurones in man.
1995
The H reflex technique was used to evaluate the influence exerted by cortical conditioning on the excitability of the alpha-motoneurone pool and on IA interneuronal activity (reciprocal inhibition). In ten subjects at absolute rest electrical and magnetic stimulation of the motor cortex was transcranially applied during flexor carpi radialis H reflex eliciting and in conditions of reciprocal inhibition induced by radial nerve stimulation. The time courses showed that at intensities below motor threshold, electrical brain conditioning induced an increase in the amplitude of the test reflex when the cortical shock was given 4 ms after the test H reflex. On the contrary, reciprocal inhibition …
Corticobulbar tract involvement in amyotrophic lateral sclerosis. A transcranial magnetic stimulation study
1998
We investigated corticobulbar tract function by recording from the tongue and orofacial muscles and using transcranial magnetic stimulation (TMS) in 30 patients with amyotrophic lateral sclerosis (ALS) in order to improve the diagnostic yield in the detection of subclinical upper motor neuron (UMN) dysfunction. A UMN lesion was assumed when the peripheral conduction time and amplitude of the M-wave were within normal range and either the response to cortical stimulation was absent, or the central conduction time was delayed (> mean + 2.5 SD). Only two patients showed clinical evidence of UMN involvement in the cranial nerves, while TMS demonstrated corticobulbar tract dysfunction in the oro…
Perceptual and response bias in visuospatial neglect due to frontal and parietal repetitive transcranial magnetic stimulation in normal subjects.
2002
Recently some authors have challenged the conventional association of directional motor neglect with damage of frontal structures, showing that pure sensory perceptual neglect (classically associated with parietal lesion) can follow damage of right frontal cortex. The aim of the present study was to assess the type of defect in visuo-spatial attention consequent upon a virtual frontal or parietal lesion induced by transcranial magnetic stimulation in normal subjects. To this purpose eleven subjects performed a visuo-spatial task requiring judgement about the length of the two segments of asymmetrically bisected horizontal lines, presented for 50 ms on a computer monitor. After each visual s…
Deafferentation and pointing with visual double-step perturbations
1999
The capability of reprogramming movement responses following changes in the visual goal has been studied through the double-step paradigm. These studies have shown that: (a) continuous internal feedback-loops correct unconsciously the dynamic errors throughout the movement; (b) proprioceptive information and/or the efference copy have a privileged status among central processes, insuring on-line regulation of the initial motor commands; and (c) generation of the motor program starts after target presentation, and is continuously updated in the direction of the current internal representation of the target, at least until the onset of hand movement. This main corrective process of the initia…