Search results for "Ceph"
showing 10 items of 2036 documents
Task relevance and recognition of concealed information have different influences on electrodermal activity and event-related brain potentials.
2009
This study aimed at differentiating between memory- and task-related processes and their correlates on the electrodermal and electrocortical level during information concealment. Variations of the Guilty Knowledge Test were implemented in two experiments while we measured skin conductance responses (SCRs) and event-related brain potentials. P300 amplitudes were specifically enhanced for items requiring a deviant behavioral response but they were not sensitive to concealed knowledge. In contrast, N200 amplitudes differed between memorized and irrelevant items in both experiments. SCR measures reflected a combined influence of task relevance and probe recognition, and they provided incrementa…
The sound of music: differentiating musicians using a fast, musical multi-feature mismatch negativity paradigm.
2011
Abstract Musicians’ skills in auditory processing depend highly on instrument, performance practice, and on level of expertise. Yet, it is not known though whether the style/genre of music might shape auditory processing in the brains of musicians. Here, we aimed at tackling the role of musical style/genre on modulating neural and behavioral responses to changes in musical features. Using a novel, fast and musical sounding multi-feature paradigm, we measured the mismatch negativity (MMN), a pre-attentive brain response, to six types of musical feature change in musicians playing three distinct styles of music (classical, jazz, rock/pop) and in non-musicians. Jazz and classical musicians sco…
The EEG and fMRI signatures of neural integration: An investigation of meaningful gestures and corresponding speech
2015
Abstract One of the key features of human interpersonal communication is our ability to integrate information communicated by speech and accompanying gestures. However, it is still not fully understood how this essential combinatory process is represented in the human brain. Functional magnetic resonance imaging (fMRI) studies have unanimously attested the relevance of activation in the posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG), while electroencephalography (EEG) studies have shown oscillatory activity in specific frequency bands to be associated with multisensory integration. In the current study, we used fMRI and EEG to separately investigate the anatomical and o…
Localization of Brain Networks Engaged by the Sustained Attention to Response Task Provides Quantitative Markers of Executive Impairment in Amyotroph…
2020
Abstract Objective: To identify cortical regions engaged during the sustained attention to response task (SART) and characterize changes in their activity associated with the neurodegenerative condition amyotrophic lateral sclerosis (ALS). Methods: High-density electroencephalography (EEG) was recorded from 33 controls and 23 ALS patients during a SART paradigm. Differences in associated event-related potential peaks were measured for Go and NoGo trials. Sources active during these peaks were localized, and ALS-associated differences were quantified. Results: Go and NoGo N2 and P3 peak sources were localized to the left primary motor cortex, bilateral dorsolateral prefrontal cortex (DLPFC),…
Is that me in the mirror? Depersonalisation modulates tactile mirroring mechanisms
2016
Our sense of self is thought to develop through sensory-motor contingencies provided, not only by observing one's own body, but also by mirroring interactions with others. This suggests that there is a strong link between mirroring mechanisms and the bodily self. The present study tested whether this link is expressed at early, implicit stages of the mirroring process or at later, more cognitive stages. We also provide, to the best of our knowledge, the first demonstration of how inter-individual differences in our sense of bodily self may affect mirroring mechanisms. We used somatosensory event-related potentials (SEPs) to investigate the temporal dynamics of mirroring highly self-related …
Spontaneous brain activity and EEG microstates. A novel EEG/fMRI analysis approach to explore resting-state networks.
2009
The brain is active even in the absence of explicit input or output as demonstrated from electrophysiological as well as imaging studies. Using a combined approach we measured spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal along with electroencephalography (EEG) in eleven healthy subjects during relaxed wakefulness (eyes closed). In contrast to other studies which used the EEG frequency information to guide the functional MRI (fMRI) analysis, we opted for transient EEG events, which identify and quantify brain electric microstates as time epochs with quasi-stable field topography. We then used this microstate information as regressors for the BOLD fluctuations. S…
Asymmetry in the human primary somatosensory cortex and handedness.
2003
Brain asymmetry is a phenomenon well known for handedness and language specialization and has also been studied in motor cortex. Less is known about hemispheric asymmetries in the somatosensory cortex. In the present study, we systematically investigated the representation of somatosensory function analyzing early subcortical and cortical somatosensory-evoked potentials (SEP) after electrical stimulation of the right and left median nerve. In 16 subjects, we compared thresholds, the peripheral neurogram at Erb point, and, using MRI-based EEG source analysis, the P14 brainstem component as well as N20 and P22, the earliest cortical responses from the primary sensorimotor cortex. Handedness w…
Early use of phonological codes in deaf readers: An ERP study.
2017
Previous studies suggest that deaf readers use phonological information of words when it is explicitly demanded by the task itself. However, whether phonological encoding is automatic remains controversial. The present experiment examined whether adult congenitally deaf readers show evidence of automatic use of phonological information during visual word recognition. In an ERP masked priming lexical decision experiment, deaf participants responded to target words preceded by a pseudohomophone (koral - CORAL) or an orthographic control prime (toral - CORAL). Responses were faster for the pseudohomophone than for the orthographic control condition. The N250 and N400 amplitudes were reduced fo…
Both contextual regularity and selective attention affect the reduction of precision‐weighted prediction errors but in distinct manners
2020
Predictive coding model of perception postulates that the primary objective of the brain is to infer the causes of sensory inputs by reducing prediction errors (i.e., the discrepancy between expected and actual information). Moreover, prediction errors are weighted by their precision (i.e., inverse variance), which quantifies the degree of certainty about the variables. There is accumulating evidence that the reduction of precision-weighted prediction errors can be affected by contextual regularity (as an external factor) and selective attention (as an internal factor). However, it is unclear whether the two factors function together or separately. Here we used electroencephalography (EEG) …
Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials
2014
The neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) have been mostly investigated by peripheral motor-evoked potentials (MEPs). New TMS-compatible EEG systems allow a direct investigation of the stimulation effects through the analysis of TMS-evoked potentials (TEPs).We investigated the effects of 1-Hz rTMS over the primary motor cortex (M1) of 15 healthy volunteers on TEP evoked by single pulse TMS over the same area. A second experiment in which rTMS was delivered over the primary visual cortex (V1) of 15 healthy volunteers was conducted to examine the spatial specificity of the effects. Single-pulse TMS evoked four main components: P30, N45, P60 and N100. M…