Search results for "Potential"
showing 10 items of 3348 documents
Physiological and metabolic actions of mycophenolate mofetil on cultured newborn rat cardiomyocytes in normoxia and in simulated ischemia
2004
Mycophenolate mofetil (MMF) is a new immunosuppressive drug used to reduce acute rejection after heart transplantation. As with other immunosuppressive drugs, MMF therapy is associated with several adverse effects. However, the direct effects of MMF on myocardial tissue has not been yet evaluated. The aim of the work was thus to evaluate the effects of MMF on isolated cardiomyocytes (CM) in normal conditions and in an in vitro model of simulated ischemia (SI; substrate-free hypoxia) and reperfusion (R; reoxygenation). Myocyte-enriched cultures were prepared from newborn rat heart ventricles. The transmembrane potentials were recorded using conventional microelectrodes and the cell contracti…
Physicochemical characterization of passive films on niobium by admittance and electrochemical impedance spectroscopy studies
2005
An analysis of the electronic properties of amorphous semiconductor-electrolyte junction is reported for thin (D ox < 20 nm) passive film grown on Nb in acidic electrolyte. It will be shown that the theory of amorphous semiconductor-electrolyte junction (a-SC/EI) both in the low band-bending and high band-bending regime is able to explain the admittance data of a-Nb 2 O 5 /El interface in a large range (10 Hz-10 kHz) of frequency and electrode potential values. A modelling of experimental EIS data at different potentials and in the frequency range of 0.1 Hz-100 kHz is presented based on the theory of amorphous semiconductor and compared with the results of the fitting of the admittance data…
SINGLE-TRIAL BASED INDEPENDENT COMPONENT ANALYSIS ON MISMATCH NEGATIVITY IN CHILDREN
2010
Independent component analysis (ICA) does not follow the superposition rule. This motivates us to study a negative event-related potential — mismatch negativity (MMN) estimated by the single-trial based ICA (sICA) and averaged trace based ICA (aICA), respectively. To sICA, an optimal digital filter (ODF) was used to remove low-frequency noise. As a result, this study demonstrates that the performance of the sICA+ODF and aICA could be different. Moreover, MMN under sICA+ODF fits better with the theoretical expectation, i.e., larger deviant elicits larger MMN peak amplitude.
Auditory Event-Related Potentials in the Study of Developmental Language-Related Disorders
1997
This article reviews recent auditory event-related potential (ERP) studies of developmental language disorder (DLD) and dyslexia/reading disorder (RD). The possibility of using ERPs in searching for precursors of these disorders in the early development of infants at risk is also discussed. Differences in exogenous/sensory ERPs at the latency range of P1 and N1-P2 components have been reported between groups with DLD and RD and control groups. Latency differences between the groups may be related to a common timing deficit suggested by some researchers to be one of the possible underlying factors both in DLD and dyslexia. N1 amplitude group differences may be partly related to arousal/atten…
Deaf readers benefit from lexical feedback during orthographic processing
2019
Published: 23 August 2019 It has been proposed that poor reading abilities in deaf readers might be related to weak connections between the orthographic and lexical-semantic levels of processing. Here we used event related potentials (ERPs), known for their excellent time resolution, to examine whether lexical feedback modulates early orthographic processing. Twenty congenitally deaf readers made lexical decisions to target words and pseudowords. Each of those target stimuli could be preceded by a briefly presented matched-case or mismatched-case identity prime (e.g., ALTAR-ALTAR vs. altar- ALTAR). Results showed an early effect of case overlap at the N/P150 for all targets. Critically, thi…
Mismatch negativity (MMN) as a tool for investigating auditory discrimination and sensory memory in infants and children
2000
For decades behavioral methods, such as the head-turning or sucking paradigms, have been the primary methods to investigate auditory discrimination, learning and the function of sensory memory in infancy and early childhood. During recent years, however, a new method for investigating these issues in children has emerged. This method makes use of the mismatch negativity (MMN), the brain's automatic change-detection response, which has been used intensively in both basic and clinical studies in adults for twenty years. This review demonstrates that, unlike many other components of event-related potentials, the MMN is developmentally quite stable and can be obtained even from pre-term infants…
Different generators in human temporal-parasylvian cortex account for subdural laser-evoked potentials, auditory-evoked potentials, and event-related…
2000
In order to localize cortical areas mediating pain we now report subdural cortical potentials evoked by auditory stimulation (auditory-evoked potentials - AEPs) and by cutaneous stimulation with a laser (laser-evoked potentials - LEPs). Stimulation with the laser evokes a pure pain sensation by selective activation of nociceptors. LEPs were maximal over the inferior aspect of the central sulcus and had the same polarity on either side of the sylvian fissure. AEPs were maximal posterior to the LEP maximum and had opposite polarity on opposite sides of the sylvian fissure, consistent with the location of a known generator in the temporal operculum. Auditory P3 (event-related) potentials were …
The attentional blink demonstrates automatic deviance processing in vision.
2011
Rare deviations in serial visual stimulation are accompanied by an occipital N2 in the event-related potential [the visual mismatch negativity (vMMN)]. Recent research suggests that the vMMN reflects automatic processing of information on the sensory level as a basis for change detection. To directly test the hypothesis that the vMMN is independent from attention, a rapid-serial-visual-presentation paradigm was applied: Either 300 ms or 700 ms after the presentation of a target (T1) a rare position change was embedded in the stimulation which elicited a vMMN. In another condition participants had to detect a second target (T2) after T1: Importantly, within 300 ms after T1, T2 detection was …
Spatiotemporal Neurodynamics Underlying Internally and Externally Driven Temporal Prediction: A High Spatial Resolution ERP Study
2015
Abstract Temporal prediction (TP) is a flexible and dynamic cognitive ability. Depending on the internal or external nature of information exploited to generate TP, distinct cognitive and brain mechanisms are engaged with the same final goal of reducing uncertainty about the future. In this study, we investigated the specific brain mechanisms involved in internally and externally driven TP. To this end, we employed an experimental paradigm purposely designed to elicit and compare externally and internally driven TP and a combined approach based on the application of a distributed source reconstruction modeling on a high spatial resolution electrophysiological data array. Specific spatiotemp…
Combining tDCS with prismatic adaptation for non-invasive neuromodulation of the motor cortex
2017
Abstract Background Prismatic adaptation (PA) shifts visual field laterally and induces lateralized deviations of spatial attention. Recently, it has been suggested that prismatic goggles are also able to modulate brain excitability, with cognitive after-effects documented even in tasks not necessarily spatial in nature. Objective The aim of the present study was to test whether neuromodulatory effects obtained from tDCS and prismatic goggles could interact and induce homeostatic changes in corticospinal excitability. Methods Thirty-four subjects were submitted to single-pulse transcranial magnetic stimulation (TMS) over the right primary motor cortex to measure Input-Output (IO) curve as a…