Search results for "Motor performance"
showing 10 items of 378 documents
Daily modulation of the speed–accuracy trade-off
2017
International audience; Goal-oriented arm movements are characterized by a balance between speed and accuracy. The relation between speed and accuracy has been formalized by Fitts’ law and predicts a linear increase in movement duration with task constraints. Up to now this relation has been investigated on a short-time scale only, that is during a single experimental session, although chronobiological studies report that the motor system is shaped by circadian rhythms. Here, we examine whether the speed–accuracy trade-off could vary during the day. Healthy adults carried out arm-pointing movements as accurately and fast as possible toward targets of different sizes at various hours of the …
Context-dependent neuroelectric responses during motor control
2015
Abstract Research on brain responses during motor control is usually performed under typical laboratory settings. However, everyday life and the laboratory differ in many aspects, such as purposeful and motivated behavior; and there's no awareness of “being measured” in everyday life. In the laboratory, movements are usually explicitly instructed, overtly measured and follow no intrinsic motivated purpose. Therefore, here we present a new method to measure and reliably analyze neuroelectric brain responses by EEG, as well as kinematics during the performance of grasping movements in two different behavioral contexts. One context (L) simulates a typical laboratory task and another context (E…
Anticipatory strategies of team-handball goalkeepers
2011
This study seeks to discover whether handball goalkeepers employ a general anticipatory strategy when facing long distance throws and the effect of uncertainty on these strategies. Seven goalkeepers and four throwers took part. We used a force platform to analyse the goalkeeper's movements on the basis of reaction forces and two video cameras synchronised at 500 Hz to film the throw using 3D video techniques. The goalkeepers initiated their movement towards the side of the throw 193 ± 67 ms before the release of the ball and when the uncertainty was reduced the time increased to 349 ± 71 ms. The kinematics analysis of their centre of mass indicated that there was an anticipatory strategy of…
Cognitive processess and cognitive reserve in multiple sclerosis
2015
Multiple Sclerosis (MS) is characterized by motor, cognitive, and neuropsychiatric symptoms, which can occur independently. While MS is traditionally considered an inflammatory disease of the white matter, degeneration of gray matter is increasingly recognized as an important contributor to the progressive cognitive decline. A protective factor against the progression of cognitive dysfunction in MS could be the cognitive reserve, defined as resistance to brain dysfunction. Aim of the present study is to evaluate the role of cognitive reserve for different aspects of cognitive dysfunction of patients with MS. We found that patients with MS and lower cognitive reserve have poorer neuropsychol…
Memory detection using fMRI - does the encoding context matter?
2015
Recent research revealed that the presentation of crime related details during the Concealed Information Test (CIT) reliably activates a network of bilateral inferior frontal, right medial frontal and right temporal-parietal brain regions. However, the ecological validity of these findings as well as the influence of the encoding context are still unclear. To tackle these questions, three different groups of subjects participated in the current study. Two groups of guilty subjects encoded critical details either only by planning (guilty intention group) or by really enacting (guilty action group) a complex, realistic mock crime. In addition, a group of informed innocent subjects encoded hal…
Neural dynamics of learning sound-action associations.
2008
A motor component is pre-requisite to any communicative act as one must inherently move to communicate. To learn to make a communicative act, the brain must be able to dynamically associate arbitrary percepts to the neural substrate underlying the pre-requisite motor activity. We aimed to investigate whether brain regions involved in complex gestures (ventral pre-motor cortex, Brodmann Area 44) were involved in mediating association between novel abstract auditory stimuli and novel gestural movements. In a functional resonance imaging (fMRI) study we asked participants to learn associations between previously unrelated novel sounds and meaningless gestures inside the scanner. We use functio…
Differences in psychomotor reaction time in male monozygotic twins discordant for lifetime cigarette smoking.
1996
The effects of long-term cigarette smoking on psychomotor reaction time were investigated among 8 pairs of monozygotic male twins highly discordant for lifetime smoking (means 32.4 versus 0.6 pack-years). The men had no diagnosed cardiovascular disease or other major diseases, musculoskeletal complaints, or vision problems that might interfere with reaction time testing. The twins had similar education, work, and exercise histories; alcohol and coffee consumption and exposure to solvents were examined as possible confounds. Direct comparison of cotwins also controlled for age, genetics, and possible early environmental factors. Simple and choice reaction time were measured in the dominant h…
Schizophrenic patients who smoke have a faster finger tapping rate than non-smokers
2002
The increased rate of smoking in schizophrenia patients remains unexplained and may reflect attempts at self-treatment. The effect sought from smoking may be related to nicotine's stimulating action. We tested this hypothesis by examining the relationship between smoking status and finger tapping rate, a measure of central processing, in schizophrenia patients treated with atypical antipsychotics. Smokers showed significantly faster finger tapping rates than non-smokers. This was not related to clinical state, illness chronicity, medication side-effects, antipsychotic dose or plasma concentrations. Nicotine can improve central processing in medicated schizophrenia patients and this may cons…
Circulating 25-Hydroxyvitamin D3 in Pregnancy and Infant Neuropsychological Development
2012
OBJECTIVE:To investigate whether circulating 25-hydroxyvitamin D3 [25(OH)D3] concentration in pregnancy is associated with neuropsychological development in infants.METHODS:The Spanish population-based cohort study INfancia y Medio Ambiente Project recruited pregnant women during the first trimester of pregnancy between November 2003 and February 2008. Completed data on 1820 mother-infant pairs were used. Maternal plasma 25(OH)D3 concentration was measured by high-performance liquid chromatography in pregnancy (mean 13.5±2.1 weeks of gestation). Offspring mental and psychomotor scores were assessed by trained psychologists at age 14 months (range, 11–23) by using the Bayley Scales of Infant…
Modulation of right motor cortex excitability without awareness following presentation of masked self-images.
2004
The neural substrates of self-awareness have been studied with a variety of neurophysiological and behavioral tools. In the present study, unconscious modulation of corticospinal excitability following presentation of self-images was probed with transcranial magnetic stimulation (TMS). TMS-induced motor evoked potentials (MEP) were collected from the contralateral first dorsal interosseus (FDI) muscle while subjects viewed masked pictures of their own face. MEP amplitudes were compared to those obtained when pictures of strangers were masked. Masked self-images induced a relative increase in corticospinal excitability when TMS was applied to the right primary motor cortex. These results dem…