OBJECTIVE Functional connectivity networks (FCNs) based on interictal electroencephalography (EEG) can identify pathological brain networks associated with epilepsy. FCNs are altered by interictal epileptiform discharges (IEDs), but it is unknown whether this is due to the morphology of the IED or the underlying pathological activity. Therefore, we characterized the impact of IEDs on the FCN through simulations and EEG analysis. METHODS We introduced simulated IEDs to sleep EEG recordings of eight healthy controls and analyzed the effect of IED amplitude and rate on the FCN. We then generated FCNs based on epochs with and without IEDs and compared them to the analogous FCNs from eight subjects with infantile spasms (IS), based on 1340 visually marked IEDs. Differences in network structure and strength were assessed. RESULTS IEDs in IS subjects caused increased connectivity strength but no change in network structure. In controls, simulated IEDs with physiological amplitudes and rates did not alter network strength or structure. CONCLUSIONS Increases in connectivity strength in IS subjects are not artifacts caused by the interictal spike waveform and may be related to the underlying pathophysiology of IS. SIGNIFICANCE Dynamic changes in EEG-based FCNs during IEDs may be valuable for identification of pathological networks associated with epilepsy. OBJECTIVE Most of knowledge on muscle radicular innervation was from explorations in root/spinal cord pathologies. Direct and individual access to each of the lumbar-sacral -ventral and dorsal- nerve roots during dorsal rhizotomy for spastic diplegia allows precise study of the corresponding muscle innervation. Authors report the lumbo-sacral segmental myotomal organization obtained from recordings of muscle responses to root stimulation in a 20-children prospective series. METHODS Seven key-muscles in each lower limb and anal sphincter were Electromyography (EMG)-recorded and clinically observed by physiotherapist during L2-to-S2 dorsal rhizotomy. Ventral roots (VR), for topographical mapping, and dorsal roots (DR), for segmental excitability testing, were stimulated, just above threshold for eliciting muscular response. RESULTS In 70% of the muscles studied, VR innervation was pluri-radicular, from 2-to-4 roots, with 1 or 2 roots being dominant at each level. Overlapping was important. Muscle responses to DR stimulation were 1.75 times more extended compared to VR stimulation. Inter-individual variability was important. CONCLUSIONS Accuracy of root identification and stimulation with the used method brings some more precise information to radicular functional anatomy. SIGNIFICANCE Those neurophysiological findings plead for performing Intra-Operative Neuromonitoring when dealing with surgery in the lumbar-sacral roots.  https://www.selleckchem.com/products/ki16198.html  OBJECTIVE Delirium is associated with increased electroencephalography (EEG) delta activity, decreased connectivity strength and decreased network integration. To improve our understanding of development of delirium, we studied whether non-delirious individuals with a predisposition for delirium also show these EEG abnormalities. METHODS Elderly subjects (N = 206) underwent resting-state EEG measurements and were assessed on predisposing delirium risk factors, i.e. older age, alcohol misuse, cognitive impairment, depression, functional impairment, history of stroke and physical status. Delirium-related EEG characteristics of interest were relative delta power, alpha connectivity strength (phase lag index) and network integration (minimum spanning tree leaf fraction). Linear regression analyses were used to investigate the relation between predisposing delirium risk factors and EEG characteristics that are associated with delirium, adjusting for confounding and multiple testing. RESULTS Functional impairment was related to a decrease in connectivity strength (adjusted R2 = 0.071, β = 0.201, p  less then  0.05). None of the other risk factors had significant influence on EEG delta power, connectivity strength or network integration. CONCLUSIONS Functional impairment seems to be associated with decreased alpha connectivity strength. Other predisposing risk factors for delirium had no effect on the studied EEG characteristics. SIGNIFICANCE Predisposition for delirium is not consistently related to EEG characteristics that can be found during delirium. OBJECTIVE To investigate the impact of sleep onset and offset on the rate of epileptiform discharges (ED) in idiopathic generalized epilepsies (IGE). METHODS We studied the temporal distribution of EDs with mixed-effects Poisson regression modeling in a cohort of patients diagnosed with IGE who underwent 24-hour ambulatory electroencephalography (EEG) recordings. We defined the mean number discharges per hour per subject as the mean ED rate. The association between each hour and the mean ED rate was quantified with incidence rate ratio (IRR) as the metric. We calculated the IRR of each hourly block for the total cohort in relation to sleep onset and offset. Finally, we admitted secondary risk factors into our Poisson regression model and quantified changes in IRR in order to investigate the impact of those variables on the outcome. The secondary risk factors included epilepsy syndrome, duration of seizure freedom, duration of epilepsy, number of antiepileptic drugs (AED), type of AED, and age. RESULTS A total of 39 patients with a mean age of 29.1 y (SD = 10.1) were studied. The distribution of ED rate demonstrated a highly significant abrupt increase in the first hour after sleep onset (IRR = 3.96; p  less then  0.001). On the contrary, the ED rate significantly dropped in the second hour after the sleep offset compared with the last hour block before sleep offset (IRR = 0.39; p  less then  0.001). None of the secondary risk factors demonstrated any significant impact on this pattern. CONCLUSIONS Sleep onset is a very significant trigger for the generation of EDs in IGE. SIGNIFICANCE Our results support the hypothesis that there is a "critical zone of vigilance" in the sleep-wake boundary from which generalized EDs are more likely to emerge.