Search results for " adaptation."
showing 10 items of 461 documents
Time and spatial attention: Effects of prism adaptation on temporal deficits in brain damaged patients
2011
Growing evidence indicates that the representations of space and time interact in the brain but the exact neural correlates of such interaction remain unknown. Neuroimaging and neuropsychological studies show that processing of temporal information engages a distributed network in the right hemisphere and suggest a link between deficits in spatial attention and deficits in time perception. In the present study we used the procedure of prismatic adaptation (PA) to directionally manipulate spatial attention in order to explore the effect of attentional deviation on time perception in patients with right (RBD) vs. left (LBD) brain damage. In a first experiment, two groups of RBD and LBD patien…
Some physiological and psychological characteristics of myopic and non-myopic young men.
2009
As a part of a research project on the health and functional capacity of men at different ages a comparison of selected physiological and psychological characteristics of myopic and non-myopic 31–35 year-old men was made. The random sample studied consisted of 31 myopic and 100 non-myopic men. It was found that the body mass index and fat content were lower among the myopic than among the non-myopic. No significant differences were found in the elastic properties of skin, in blood pressure or in haematological assays studied between the groups. With respect to physical performance it was observed that the myopic had a higher aerobic capacity whereas there were no significant differences in …
Neural and mechanical responses of the triceps surae muscle group after 1 h of repeated fast passive stretches
2004
Experiments were carried out to examine interaction between mechanical changes of the muscletendon unit and reduced reflex sensitivity after repeated and prolonged passive muscle stretching (RPS). There is some evidence that this interaction might be relevant also during active stretch-shortening cycle type of fatigue tasks. The results demonstrated a clear deterioration of voluntarily and electrically induced muscle contractions after RPS. Maximal voluntary contraction (MVC), average electromyographic activities of the gastrocnemius and soleus muscles, and maximal twitch contraction decreased on average by 13.8, 10.4, 7.6, and 16.8%, respectively. In addition, there was a 14% lengthening …
Dependence of Perceived Purity of a Chromatic Stimulus on Saturation Adaptation
2012
Background and Objective. The purpose of sensory adaptation of the visual system is to adjust sensitivity of the photoreceptors to optimize the dynamic range of response of the visual system. It has been shown in numerous research papers that chromatic adaptation influences both color appearance and color discrimination. However, there are almost no studies in which the influence of chromatic adaptation on perceived purity has been investigated. Therefore, the aim of this study was to investigate how chromatic adaptation to stimuli with certain saturation influences perceived purity of test stimuli with the same hue but different saturation. Material and Methods. As the stimuli were modulat…
Two-year clinical performance of a packable posterior composite with and without a flowable composite liner
2003
The aim of the study was to evaluate the clinical performance of a packable fine hybrid dental composite (Prodigy Condensable) and the influence of the additional application of a flowable resin composite (Revolution, SDS Kerr) layer on marginal integrity after 2 years in stress-bearing posterior cavities according to the Ryge criteria. In 50 patients (40.5+/-17.5 years of age), 116 class II fillings (metal matrix system, glass ionomer-cement-base in 36%, rubberdam isolation in 70%) were placed, with at least two restorations per patient. The adhesive Optibond Solo Plus was used for all the restorations. In one of the two fillings in each patient, an additional layer of the flowable composi…
Cross-notational semantic priming between symbolic and nonsymbolic numerosity
2008
Symbolic and nonsymbolic numerosities produce similar behavioural effects and activate the same brain areas. These results have usually been interpreted in terms of a common, notation-independent magnitude representation. However, semantic priming between symbolic and nonsymbolic inputs has been somehow elusive (e.g., Koechlin, Naccache, Block, & Dehaene, 1999). In Experiment 1, we looked at whether cross-notational semantic priming depends on exact numerical meaning. Dice faces and digits were mixed as prime and target. Semantic priming occurred when prime and target were in the same notation as much as when they were in different notation. In Experiment 2, we found cross-notation sem…
Prism adaptation by mental practice
2012
International audience; The prediction of our actions and their interaction with the external environment is critical for sensorimotor adaptation. For instance, during prism exposure, which deviates laterally our visual field, we progressively correct movement errors by combining sensory feedback with forward model sensory predictions. However, very often we project our actions to the external environment without physically interacting with it (e.g., mental actions). An intriguing question is whether adaptation will occur if we imagine, instead of executing, an arm movement while wearing prisms. Here, we investigated prism adaptation during mental actions. In the first experiment, participa…
Methodological Aspects of the Application of the Naka-Rushton Equation to Clinical Electroretinogram
1993
The nonlinear relation between stimulus intensity and response amplitude of the electroretinogram (ERG) scotopic b wave can be described by a curve based on the Naka-Rushton (NR) equation. Up to now, the NR equation has been used to assess the features of the normal and pathological ERG, but the best approach for a correct evaluation of the parameters is still debatable. The parameters are thought to be related to the different conditions of retinal activities. The method is well known in experimental laboratories but is quite unusual at the clinical level. In the present paper the derivative analysis of the NR function is proposed as an easier approach to understand the variations of the N…
Prismatic Adaptation Modulates Oscillatory EEG Correlates of Motor Preparation but Not Visual Attention in Healthy Participants.
2017
Prismatic adaption (PA) has been proposed as a tool to induce neural plasticity and is used to help neglect rehabilitation. It leads to a recalibration of visuomotor coordination during pointing as well as to aftereffects on a number of sensorimotor and attention tasks, but whether these effects originate at a motor or attentional level remains a matter of debate. Our aim was to further characterize PA aftereffects by using an approach that allows distinguishing between effects on attentional and motor processes. We recorded EEG in healthy human participants (9 females and 7 males) while performing a new double step, anticipatory attention/motor preparation paradigm before and after adaptat…
Preattentive and attentive responses to changes in small numerosities of tones in adult humans
2016
The brain hosts a primitive number sense to non-symbolically represent numerosities of objects or events. Small exact numerosities (~4 or less) can be individuated in parallel. In contrast, large numerosities (more than ~4) can only be approximated. However, whether small numerosities can be approximated without their parallel individuation remains unclear. Parallel individuation is suggested to be an attentive process and numerical approximation an automatic process. We, therefore, tested whether small numerosities can be represented preattentively. We recorded adult humans׳ event-related potentials (ERPs) and behavioral responses to 300-ms sequences of six tones (each of either 440 Hz or …