Search results for " potential"
showing 10 items of 2713 documents
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…
Think globally: Cross-linguistic variation in electrophysiological activity during sentence comprehension
2011
This paper demonstrates systematic cross-linguistic differences in the electrophysiological correlates of conflicts between form and meaning (“semantic reversal anomalies”). These engender P600 effects in English and Dutch (e.g. Kolk et al., 2003 ; Kuperberg et al., 2003), but a biphasic N400 – late positivity pattern in German (Schlesewsky and Bornkessel-Schlesewsky, 2009), and monophasic N400 effects in Turkish (Experiment 1) and Mandarin Chinese (Experiment 2). Experiment 3 revealed that, in Icelandic, semantic reversal anomalies show the English pattern with verbs requiring a position-based identification of argument roles, but the German pattern with verbs requiring a case-based identi…
Dynamic image denoising for voxel-wise quantification with Statistical Parametric Mapping in molecular neuroimaging.
2018
Purpose PET and SPECT voxel kinetics are highly noised. To our knowledge, no study has determined the effect of denoising on the ability to detect differences in binding at the voxel level using Statistical Parametric Mapping (SPM). Methods In the present study, groups of subject-images with a 10%- and 20%- difference in binding of [123I]iomazenil (IMZ) were simulated. They were denoised with Factor Analysis (FA). Parametric images of binding potential (BPND) were produced with the simplified reference tissue model (SRTM) and the Logan non-invasive graphical analysis (LNIGA) and analyzed using SPM to detect group differences. FA was also applied to [123I]IMZ and [11C]flumazenil (FMZ) clinic…
Breakdown of Thalamo-Cortical Connectivity Precedes Spike Generation in Focal Epilepsies
2017
Electroencephalography (EEG) spikes and focal epileptic seizures are generated in circumscribed cerebral networks that have been insufficiently described. For precise time and spatial domain network characterization, we applied in patients with focal epilepsy dense array 256-channel EEG recordings with causal connectivity estimation by using time-resolved partial directed coherence and 3T-magnetic resonance imaging-derived cortical and thalamus integrity reconstruction. Before spike generation, significant theta and alpha bands driven information flows alterations were noted from both temporal and frontal lobes to the thalamus and from the thalamus to the frontal lobe. Medial dorsal and ven…
The influence of scene and object orientation on the scene consistency effect
2019
Abstract Contextual regularities help us make sense of our visual environment. In scenes, semantically consistent objects are typically better recognized than inconsistent ones (e.g., a toaster vs. printer in a kitchen). What is the role of object and scene orientation in this so-called scene consistency effect? We presented consistent and inconsistent objects either upright (Experiment 1) or inverted (rotated 180°; Experiment 2) on upright, inverted, and scrambled background scenes. In Experiment 1, on upright scenes, consistent objects were recognized with higher accuracy than inconsistent ones, and we observed N300/N400 event-related potentials (ERPs) reflecting object-scene semantic pro…
Neurocognitive processing of auditorily and visually presented inflected words and pseudowords: Evidence from a morphologically rich language
2009
The aim of the study was to investigate how the input modality affects the processing of a morphologically complex word. The processing of Finnish inflected vs. monomorphemic words and pseudowords was examined during a lexical decision task, using behavioral responses and event-related potentials. The stimuli were presented in two modalities, visually and auditorily, to two groups of participants. Half of the words and pseudowords carried a case-inflection. At the behavioral level, the inflected words elicited a processing cost with longer decision latencies and higher error rates. At the neural level, pseudowords elicited an N400 effect, which was more pronounced in the visual modality. In…
Music-induced positive mood broadens the scope of auditory attention
2017
Previous studies indicate that positive mood broadens the scope of visual attention, which can manifest as heightened distractibility. We used event-related potentials (ERP) to investigate whether music-induced positive mood has comparable effects on selective attention in the auditory domain. Subjects listened to experimenter-selected happy, neutral or sad instrumental music and afterwards participated in a dichotic listening task. Distractor sounds in the unattended channel elicited responses related to early sound encoding (N1/MMN) and bottom-up attention capture (P3a) while target sounds in the attended channel elicited a response related to top-down-controlled processing of task-releva…
The relative contribution to the plantar-flexor torque of the soleus motor units activated by the H reflex and M response in humans.
2000
Abstract This study proposes a method of quantifying the relative contribution to the plantar-flexor torque of soleus H and M responses evoked by tibial nerve stimulation. For ten subjects, the amplitude of the twitch produced by the H wave was plotted against the corresponding potential, for stimuli producing H without M (i.e. in the ascending portion of the H-recruitment curve). It was then assumed that the contribution of H to twitches produced by M plus H was similar for similar H waves on the curve-descending portion. Hence, the contribution of M was estimated, for the range of M waves including those accompanying H max . The estimated mechanical contributions of H and M wave increase …
Habituation and laterality of orienting processes as reflected by slow negative waves
2000
The study is concerned with the question of whether the orienting wave (O-wave), a slow potential shift of the event-related brain potential, is a component of the orienting response (OR). As habituation is supposed to be the most important characteristic of the OR, we focussed particularly on any habituating aspect of the O-wave. Results suggest that its bilateral distribution over midfrontal areas might constitute such a link relating the O-wave to orienting activity. Hemispheric asymmetry linearly decreased its right-sided predominance in response to repeated presentations of an initially novel auditory stimulus. A similar, concomitant diminution of the skin conductance response (SCR) oc…