Search results for "SYSTEMS"
showing 10 items of 11952 documents
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…
Visual quality comparison of conventional and Hole-Visian implantable collamer lens at different degrees of decentering
2013
Purpose To compare the visual quality of implantable collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering. Methods An adaptive optics visual simulator (crx1, Imagine Eyes, Orsay, France) was used to simulate the –3, –6 and –12 dioptres (D) conventional and Hole ICLs in three conditions: centred and decentred 0.3 and 0.6 mm. Visual acuity (VA) at high-contrast, medium-contrast and low-contrast and contrast sensitivity (CS) were measured in 15 observers for 3 and 4.5 mm pupils. Results No statistically significant differences in VA and CS were found between conventional and Hole ICLs for any ICL powers and pupil sizes evaluated …
Perceptual correlates of nociceptive long-term potentiation and long-term depression in humans.
2004
Long-term potentiation (LTP) and long-term depression (LTD) of synaptic strength are ubiquitous mechanisms of synaptic plasticity, but their functional relevance in humans remains obscure. Here we report that a long-term increase in perceived pain to electrical test stimuli was induced by high-frequency electrical stimulation (HFS) (5 × 1 sec at 100 Hz) of peptidergic cutaneous afferents (27% above baseline, undiminished for >3 hr). In contrast, a long-term decrease in perceived pain (27% below baseline, undiminished for 1 hr) was induced by low-frequency stimulation (LFS) (17 min at 1 Hz). Pain testing with punctate mechanical probes (200 μm diameter) in skin adjacent to the HFS–LFS con…
Clinical evaluation criteria for the assessment of impaired pain sensitivity by thulium-laser evoked potentials
2000
Abstract Objectives : Cortical potentials evoked by carbon dioxide laser pulses have been applied in clinical practice to study nociceptive pathways for several years. In this study, we evaluate the properties of an infrared laser (thulium-YAG) with a penetration depth in the skin that matches the intracutaneous depth of nociceptors. Methods : Temperature measurements and modelling showed that the thulium laser generates painful intracutaneous temperatures with less surface heating than the carbon dioxide laser and with no side effects (up to 600 mJ pulse energy). To develop clinical evaluation criteria, laser-evoked potentials (LEPs) were recorded from 3 midline positions (Fz, Cz, Pz) vers…
Hand-arm vibration syndrome: clinical characteristics, conventional electrophysiology and quantitative sensory testing.
2013
Abstract Objective Workers exposed to vibrating tools may develop hand-arm vibration syndrome (HAVS). We assessed the somatosensory phenotype using quantitative sensory testing (QST) in comparison to electrophysiology to characterize (1) the most sensitive QST parameter for detecting sensory loss, (2) the correlation of QST and electrophysiology, and (3) the frequency of a carpal tunnel syndrome (CTS) in HAVS. Methods QST, cold provocation tests, fine motor skills, and median nerve neurography were used. QST included thermal and mechanical detection and pain thresholds. Results Thirty-two patients were examined (54 ± 11 years, 91% men) at the more affected hand compared to 16 matched contro…
Family-centered practices and the parental well-being of young children with disabilities and developmental delay.
2019
Abstract Background Research evidence from studies in North America on the relationships between family-centered practices, parents’ self-efficacy beliefs, parenting confidence and competence beliefs, and parents’ psychological well-being was used to confirm or disconfirm the same relationships in two studies in Spain. Aims The aim of Study 1 was to determine if results from studies in North America could be replicated in Spain and the aim of Study 2 was to determine if results from Study 1 could be replicated with a second sample of families in Spain. Methods and procedures A survey including the study measures was used to obtain data needed to evaluate the relationships among the variable…
Clinical patterns and electrophysiological findings in retinal pigment epithelium diseases. Does a correlation exist?
1986
At present it is difficult to distinguish those human chorioretinal diseases in which the retinal pigment epithelium (RPE) is the primary site of dysfunction. This difficulty is caused by several factors such as scarcity of biochemical and histological information and a lack of correlation of basic science information available with the clinical body of knowledge. In the present study we examined 134 eyes at early or late stages of hereditary diseases involving the RPE. We tried to distinguish primary RPE involvement by using standard ERG (a- and b-wave) and EOG testing. We conclude that in general primary RPE damage can be better assessed by current electrophysiology in those diseases whic…
The behaviour of OKT3-, OKT4- and OKT8-positive cells during phases of elevated spontaneous chemiluminescence activity (CL-A) in multiple sclerosis p…
1987
The chemiluminescence activity (CL-A; synonym = burst activity, BA) and the percentage of OKT3-, OKT4- and OKT8-positive peripheral blood cells were serially examined in four control persons and in eight patients with multiple sclerosis. When the OKT values obtained in phases of increased CL-A (clinical remission) were compared with those of the control group, the percentage of OKT3-positive cells was reduced (P = 0.014), and that of OKT4-positive cells increased (P = 0.014); there were no significant changes in the percentage of OKT8-positive cells (P = 0.171). After the CL-A had returned to normal values, the OKT4-positive cells remained elevated (P = 0.029), whereas the OKT3- (P = 0.342)…
Cytotoxic and genotoxic effects of electronic cigarette liquids on human mucosal tissue cultures of the oropharynx
2016
The popularity of electronic cigarettes (ECs) is rapidly growing and ECs are claimed to be an uncritically regarded alternative to conventional cigarettes. The mucosal tissue of the upper aerodigestive tract (UADT) is the first contact organ for xenobiotics such as liquids of ECs. The aim of this study is to investigate the bimolecular effects of e-liquids on human pharyngeal tissue cultures to evaluate whether e-liquids and their components present a risk factor for head and neck squamous cell carcinoma. Fresh tissue samples of healthy oropharyngeal mucosa were assembled into mucosal tissue cultures. Two fruit-flavored liquids (FLs), one tobacco-flavored liquid (TL) (all containing nicotin…