Search results for "Performance."
showing 10 items of 4178 documents
Pointing to a target from an upright position in human: tuning of postural responses when there is target uncertainty
2000
International audience; Human subjects performed, from a standing position, rapid hand pointings to visual targets located within or beyond the prehension space. To examine the interaction between posture and the goal-directed movement we introduced a visual double-step perturbation requiring a reprogramming of the hand movement. Trials directed towards the same spatial goal but differentiated only by the likeliness of a visual double-step were compared. The hand kinematics was not affected by the uncertainty of the visual perturbation; an increased trunk bending, however, was observed. This suggests that uncertainty constraints are integrated in a predictive manner for the optimal coordina…
Inter-joint coordination of posture on a seesaw device
2016
Even though specific adjustments of the multi-joint control of posture have been observed when posture is challenged, multi-joint coordination on a seesaw device has never been accurately assessed. The current study was conducted in order to investigate the multi-joint coordination when subjects were standing on either a seesaw device or on a stable surface, with the eyes open or closed. Eighteen healthy active subjects were recruited. A principal component analysis and a Self-Organizing Maps analysis were performed on the joint angles in order to detect and characterize dominant coordination patterns. Intermuscular EMG coherence was analysed in order to assess the neurophysiological mechan…
Role of sensorimotor areas in early detection of motor errors: An EEG and TMS study
2019
Abstract Action execution is prone to errors and, while engaged in interaction, our brain is tuned to detect deviations from what one expects from other’s action. Prior research has shown that Event-Related-Potentials (ERPs) are specifically modulated by the observation of action mistakes interfering with goal achievement. However, in complex and modular actions, embedded motor errors do not necessarily produce an immediate effect on the global goal. Here we dissociate embedded motor goals from global action goals by asking subjects to observe familiar but untrained knotting actions. During knotting an embedded motor error (i.e. the rope is inserted top-down instead of bottom-up during the …
Questionning and reading goals: information seeking questions asked on scientific texts read under different task conditions
2013
Background: A number of studies report that few questions are asked in classrooms and that many of them are shallow questions. Aims: This study investigates the way in which reading goals determine questioning on scientific texts. Reading goals were manipulated through two different tasks: reading for understanding versus reading to solve a problem. Sample: A total of 183 university students. Methods: In the first and third questioning experiments the participants read two short texts. Students in one condition were instructed to understand the texts, while in the alternative condition they had to read texts to solve a problem. Students were instructed to write down any questions they might…
Is the go/no-go lexical decision task an alternative to the yes/no lexical decision task?
2002
In the go/no-go lexical decision task (LDT), participants are instructed to respond as quickly as they can when a word is presented and not to respond if a nonword is presented. By minimizing part of the response selection process in the experimental task, the impact of response decision time on the obtained lexical decision time is probably reduced relative to the standard yes/no LDT (Gordon, 1983). Experiments 1 and 2 show that the go/no-go LDT is sensitive to the effects of word frequency and associative priming--the magnitude of these effects is similar with the two tasks. More important, the go/no-go LDT has a number of advantages with respect to the "standard" yes/no LDT: It offers fa…
Biomechanical analysis of different starting strategies utilized during cross-country skiing starts
2016
The present study was designed to analyse and compare the kinetics and kinematics associated with three different starting strategies during classic cross-country ski racing. Inside a ski tunnel, 12 elite male skiers performed three sets of three 38 m starts. Each set included one start using: double poling only (DP), diagonal stride only (DIA) and freely chosen (FREE) (i.e. where subjects used the strategy or combination of strategies they felt was fastest) in random order. The first 18 m was performed on a series of force plates that measured horizontal and vertical forces followed by 20 m of a standard snow track. Additionally, cycle characteristics and joint angles were measured. DIA an…
The remapping of time by active tool-use
2015
Multiple, action-based space representations are each based on the extent to which action is possible toward a specific sector of space, such as near/reachable and far/unreachable. Studies on tool-use revealed how the boundaries between these representations are dynamic. Space is not only multidimensional and dynamic, but it is also known for interacting with other dimensions of magnitude, such as time. However, whether time operates on similar action-driven multiple representations and whether it can be modulated by tool-use is yet unknown. To address these issues, healthy participants performed a time bisection task in two spatial positions (near and far space) before and after an active …
Age at surgery as a predictor of cognitive improvements in patients with drug-resistant temporal epilepsy
2017
Temporal lobe epilepsy (TLE) surgery is an effective procedure that can produce cognitive changes. However, the prognostic factors related with cognitive outcomes need to be better understood. The aim of the present study is to know if age at surgery is a reliable predictor of verbal memory competence and considering factors such as: hemisphere; type of surgery; pre-surgical seizure frequency; and epilepsy duration. Sixty-one typically dominant patients with drug-resistant TLE (34 with left TLE [L-TLE] and 27 with right TLE [R-TLE]) underwent a neuropsychological assessment before and a year after surgery. Results showed that R-TLE patients had better evolution in short- and long-term verba…
Difficult memory task during postural tasks of various difficulties in young and older people: A pilot study
2007
Abstract Objective This study examined the effects of a difficult and individually tailored additional cognitive task on postural stability and electromyographic (EMG) activities of the ankle dorsi- and plantar-flexors, in young and older individuals performing postural tasks of varying difficulties. Methods Eight young (mean age = 24 years) and eight older (74 years) men took part in the investigation. Centre of pressure velocity and surface EMG of ankle joint muscles were both examined during various postural conditions. Results The main findings suggested that high levels of muscle activity were a characteristic of age-related declines in postural stability. Moreover, during the complex …
Task-induced deactivation in diverse brain systems correlates with interindividual differences in distinct autonomic indices
2018
AbstractNeuroimaging research has shown that different cognitive tasks induce relatively specific activation patterns, as well as less task-specific deactivation patterns. Here we examined whether individual differences in Autonomic Nervous System (ANS) activity during task performance correlate with the magnitude of task-induced deactivation. In an fMRI study, participants performed a continuous mental arithmetic task in a task/rest block design, while undergoing combined fMRI and heart / respiration rate acquisitions using photoplethysmograph and respiration belt. As expected, task performance increased heart-rate and reduced the RMSSD, a cardiac index related to vagal tone. Across partic…