Search results for "Ceph"
showing 10 items of 2036 documents
Sleep phenotypes of intellectual disability: a polysomnographic evaluation in subjects with Down syndrome and Fragile X syndrome
2008
Abstract Objective To analyze sleep architecture and NREM sleep alterations by means of the Cyclic Alternating Pattern (CAP) in children with Down syndrome (DS) and Fragile-X syndrome (fraX), the two most common causes of inherited mental retardation, in order to find out eventual alterations of their sleep microstructure related to their mental retardation phenotypes. Methods Fourteen patients affected by fraX (mean age 13.1 years) and 9 affected by Down syndrome (mean age 13.8 years) and 26 age-matched normal controls were included. All subjects underwent overnight polysomnography in the sleep laboratory, after one adaptation night and their sleep architecture and CAP were visually scored…
Evidence for early activation of primary motor cortex and SMA after electrical lower limb stimulation using EEG source reconstruction
2006
Compared to median nerve somatosensory evoked potentials (SEP), less is known about activity evoked by nerve stimulation of the lower limb. To understand the mechanisms and the physiology of sensor- and motor control it is useful to investigate the sensorimotor functions as revealed by a standardized functional status. Therefore, we investigated SEPs of the lower limb in 6 healthy male volunteers. For each side, tibial and peroneal nerves were stimulated transcutaneously at the fossa poplitea. The tibial nerves were also stimulated further distally at the ankle joint. Source localization was applied to 64-EEG-channel data of the SEPs. In contrast to somatosensory areas, which are activated …
Two Distinct Auditory-Motor Circuits for Monitoring Speech Production as Revealed by Content-Specific Suppression of Auditory Cortex
2015
Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehear…
Macrostructural EEG characterization based on nonparametric change point segmentation: application to sleep analysis
2001
In the present investigation a new methodology for macrostructural EEG characterization based on automatic segmentation has been applied to sleep analysis. A nonparametric statistical approach for EEG segmentation was chosen, because it minimizes the need for a priori information about a signal. The method provides the detection of change-points i.e. boundaries between quasi-stationary EEG segments based on the EEG characteristics within four fundamental frequency bands (delta, theta, alpha and beta). Polysomnographic data of 18 healthy subjects were analyzed. Our findings show that nonparametric change-point segmentation in combination with cluster analysis enables us to obtain a clear pic…
Sensitivity of laser-evoked potentials versus somatosensory evoked potentials in patients with multiple sclerosis
2003
Somatosensory evoked potentials (SEPs) play a less important role in the diagnosis of multiple sclerosis (MS) than visually evoked potentials. Since standard SEPs only reflect the dorsal column function, we now investigated spinothalamic tract function in patients with MS using laser-evoked potentials (LEPs).LEPs to thulium laser stimuli (3ms, 540 mJ, 5mm diameter) were recorded from 3 midline positions (Fz, Cz, Pz) in 20 patients with MS, and 6 patients with possible but unconfirmed MS. Peak latencies and peak-to-peak amplitude of the vertex potential negativity (N2) and positivity (P2) were evaluated and compared with normative values from 22 healthy control subjects. Median and tibial ne…
Animacy-based predictions in language comprehension are robust: contextual cues modulate but do not nullify them
2015
Couldn't a humble coconut hurt a gardener? At least in the first instance, the brain seems to assume that it should not: we perceive inanimate entities such as coconuts as poor event instigators ("Actors"). Ideally, entities causing a change in another entity should be animate and this assumption not only influences event perception but also carries over to language comprehension. We present three auditory event-related brain potential (ERP) studies on the processing of inanimate and animate subjects and objects in simple transitive sentences in Tamil. ERP responses were measured at the second argument (event participant) in all three studies. Experiment 1 employed all possible animacy comb…
Thanatophoric dysplasia in monozygotic twins discordant for cloverleaf skull: Prenatal diagnosis, clinical and pathological findings
1992
We present male monozygotic twins with thanatophoric dysplasia (TD) type I concordant for long bone abnormalities and discordant for cloverleaf skull. The twins were the product of the second pregnancy of unrelated parents, with advanced paternal age. Prenatal diagnosis and postmortem examination showed severe rhizomelic shortness of limbs, bowing of the long bones with "telephone-receiver" femora in both twins, and cloverleaf skull and hydrocephalus in one of them. It is now accepted that most of cases of TD, such as in the present report, represent an autosomal dominant mutation with a high new mutations rate.
Effects of antiepileptic drugs on cortical excitability in humans: A TMS-EMG and TMS-EEG study.
2018
Brain responses to transcranial magnetic stimulation (TMS) recorded by electroencephalography (EEG) are emergent noninvasive markers of neuronal excitability and effective connectivity in humans. However, the underlying physiology of these TMS-evoked EEG potentials (TEPs) is still heavily underexplored, impeding a broad application of TEPs to study pathology in neuropsychiatric disorders. Here we tested the effects of a single oral dose of three antiepileptic drugs with specific modes of action (carbamazepine, a voltage-gated sodium channel (VGSC) blocker; brivaracetam, a ligand to the presynaptic vesicle protein VSA2; tiagabine, a gamma-aminobutyric acid (GABA) reuptake inhibitor) on TEP a…
Online detection of rem sleep based on the comprehensive evaluation of short adjacent eeg segments by artificial neural networks
1997
Abstract 1. 1. For scientific and clinical requirements the present objective is a robust automatic online algorithm to detect rapid eye movement (REM) steep from single channel sleep EEG data without using EMG or EOG information. 2. 2. For data preprocessing 20 seconds time periods of the continuous EEG activity are digitally filtered in 7 frequency bands. Then the RMS values of these filtered signals are calculated along segments of 2.5 seconds. The resulting matrix of RMS values is representing information on the power of the signal localized in time and frequency and serves as input to an artificial neural network. A pooled set of EEG data together with the corresponding manual evaluati…
Time course of emotion-related responding during distraction and reappraisal
2014
Theoretical accounts of emotion regulation (ER) discriminate various cognitive strategies to voluntarily modify emotional states. Amongst these, attentional deployment (i.e. distraction) and cognitive change (i.e. reappraisal), have been shown to successfully down-regulate emotions. Neuroimaging studies found that both strategies differentially engage neural structures associated with selective attention, working memory and cognitive control. The aim of this study was to further delineate similarities and differences between the ER strategies reappraisal and distraction by investigating their temporal brain dynamics using event-related potentials (ERPs) and their patterns of facial expressi…