Treatment of Childhood Reflex Epilepsies

Reflex epilepsies are characterized by the presence of epileptic seizures, which are consistently or stereotypically evoked by a specific afferent stimulus (i.e., flashes of light, startles, a particular movement, or cognitive task). Seizures in them are generally refractory to medical treatment requiring polytherapy. Avoiding the trigger and antiepileptic therapy may likely abolish these seizures. However, in some cases, the use of specific technologies and addressing associated comorbidities may be necessary. In this study, we review the pathophysiological basis for different treatment approaches as well as recent advances in the management of reflex epilepsies.

ВИКОРИСТАННЯ ЗАСОБІВ ІКТ У ПРОЦЕСІ ЕКСПЕРИМЕНТАЛЬНОГО ДОСЛІДЖЕННЯ ЕМОТИВНО-ОЦІННОГО СТАВЛЕННЯ УЧНІВ ДО РІЗНИХ ФОРМ ТЕСТОВИХ ЗАВДАНЬ З УКРАЇНСЬКОЇ МОВИ

The article reflects the results of one of the stages of the study, which is connected with determining the characteristics of the influence of various factors on the effective test scores. In particular, the connection between the respondents' emotionally-estimated attitude to various forms of responses to test tasks and the results of their implementation is examined. The proposed study was conducted with using of the authors' tests in the field of Ukrainian language. To determine the generalized students' assessment of the forms of answers, proposed in these tests, we used questionnaire, developed according to the method of semantic differential, which allowed to build a profile of the characteristics of the test in accordance with the semantic cognitive space of the sample. The results of respondents' assessment of response forms are generally correlated with test results and can be an additional explanatory element of their analysis and a prognostic element in the process of further designing and applying the tests. The use of factor analysis of the research results allowed: 1) to draw conclusions about the influence of the response forms offered in the test on the respondents' general perception of test tasks regardless of its content; 2) to justify the assumption that the form of test tasks and answers, as an externally organized test constructs, are a sensory afferent stimulus of the operational imagination of the activity, which, in particular, is expressed in the formation of interest and motivation to doing an assignment. An analysis of the respondents' generalized perception of the separate forms of answers showed the need for combining various forms of test tasks and the forms of answers they defined, both for the formation of positive attitudes and the motivational optimum in the process of their implementation, and for verification and refinement the test results.

Exercise intensity independently modulates thermal behavior during exercise recovery but not during exercise

We tested the hypothesis that thermal behavior is greater during and after high- compared with moderate-intensity exercise. In a 27°C, 20% relative humidity environment, 20 participants (10 women, 10 men) cycled for 30 min at moderate [53% (SD 6) peak oxygen uptake (V̇o2peak) or high [78% (SD 6) V̇o2peak] intensity, followed by 120 min of recovery. Mean skin and core temperatures and mean skin wettedness were recorded continuously. Participants maintained thermally comfortable neck temperatures with a custom-made neck device. Neck device temperature provided an index of thermal behavior. The weighted average of mean skin and core temperatures and mean skin wettedness provided an indication of the afferent stimulus to thermally behave. Mean skin and core temperatures were greater at end-exercise in high intensity ( P < 0.01). Core temperature remained elevated in high intensity until 70 min of recovery ( P = 0.03). Mean skin wettedness and the afferent stimulus were greater at 10–20 min of exercise in high intensity ( P ≤ 0.03) and remained elevated until 60 min of recovery ( P < 0.01). Neck device temperature was lower during exercise in high versus moderate intensity ( P ≤ 0.02). There was a strong relation between the afferent stimulus and neck device temperature during exercise (high: R2 = 0.82, P < 0.01; moderate: R2 = 0.95, P < 0.01) and recovery (high: R2 = 0.97, P < 0.01; moderate: R2 = 0.93, P < 0.01). During exercise, slope ( P = 0.49) and y-intercept ( P = 0.91) did not differ between intensities. In contrast, slope was steeper ( P < 0.01) and y-intercept was higher ( P < 0.01) during recovery from high-intensity exercise. Thermal behavior is greater during high-intensity exercise because of the greater stimulus to behave. The withdrawal of thermal behavior is augmented after high-intensity exercise. NEW & NOTEWORTHY This is the first study to determine the effects of exercise intensity on thermal behavior. We show that exercise intensity does not independently modulate thermal behavior during exercise but is dependent on the magnitude of afferent stimuli. In contrast, the withdrawal of thermal behavior after high-intensity exercise is augmented. This may be a consequence of an attenuated perceptual response to afferent stimuli, which may be due to processes underlying postexercise hypoalgesia.

NMDA-Receptor-Dependent Synaptic Activation of Voltage-Dependent Calcium Channels in Basolateral Amygdala

Afferent stimulation of pyramidal cells in the basolateral amygdala produced mixed excitatory postsynaptic potentials (EPSPs) mediated by N-methyl-d-aspartate (NMDA) and non-NMDA glutamate receptors during whole cell current-clamp recordings. In the presence of GABAA receptor blockade, the mixed EPSPs recruited a large “all-or-none” depolarizing event. This recruited event was voltage dependent and had a distinct activation threshold. An analogous phenomenon elicited by exogenous glutamate in the presence of tetrodotoxin (TTX) was blocked by Cd2+, suggesting that the event was a Ca2+ spike. Selective glutamatergic blockade revealed that these Ca2+ spikes were recruited readily by single afferent stimulus pulses that elicited NMDA EPSPs. In contrast, non-NMDA EPSPs induced by single stimuli failed to elicit the Ca2+ spike even at maximal stimulus intensities although these non-NMDA EPSPs depolarized the soma more effectively than mixed EPSPs. Elongation of non-NMDA EPSPs by cyclothiazide or brief trains of stimulation were also unable to elicit the Ca2+ spike. Blockade of K+ channels with intracellular Cs+enabled single non-NMDA EPSPs to activate the Ca2+ spike. The finding that voltage-dependent calcium channels are activated preferentially by NMDA-receptor-mediated EPSPs provides a mechanism for NMDA-receptor-dependent plasticity independent of Ca2+influx through the NMDA receptor.

Kinetics of Muscarinic Reduction of I sAHP in Hippocampal Neurons: Effects of Acetylcholinesterase Inhibitors

Zhang, Y., P. L. Carlen, and L. Zhang. Kinetics of muscarinic reduction of I sAHP in hippocampal neurons: effects of acetylcholinesterase inhibitors. J. Neurophysiol. 78: 2999–3007, 1997. The present experiments were designed to elucidate the time frame in which an evoked cholinergic impulse decreases the Ca2+-dependent K+ current ( I sAHP) in hippocampal CA1 neurons, and to determine to what extent acetylcholinesterase (AChE) inhibitors enhance the efficacy of the cholinergic impulse. Whole cell voltage-clamp recordings were performed on hippocampal CA1 neurons of rat brain slices and I sAHPs were evoked by constant depolarizing pulses. Cholinergic afferent fibers in stratum oriens were stimulated electrically and the time interval between the afferent stimulus and the depolarizing pulse was varied from 1 to 30 s. In slices perfused with the standard external medium, the afferent stimulus caused a profound decrease in the following I sAHP only when the stimulus preceded the depolarizing pulse by 1–2 s. The stimulus was without effects on the I sAHP when applied ≥5s before the depolarizing pulse. The effects of the afferent stimulus were greatly enhanced in CA1 neurons exposed to the catalytic AChE inhibitors neostigmine, physostigmine, or 9-amino-1,2,3,4-tetrahydro-acridine. A substantial decrease in the I sAHP was observed even when the stimulus preceded the depolarizing pulse by ≥30 s. However applications of peripheral site AChE inhibitors decamethonium and propidium caused only minor or no enhancement of the I sAHP reduction after the afferent stimulus. We suggest in physiological conditions that muscarinic modulation of ionic conductances of CNS neurons has a limited time course after a cholinergic impulse and that the modulation is greatly enhanced and prolonged when catalytic activities of AChEs are suppressed pharmacologically.

Atropine inhibits gastric distension and pharyngeal receptor mediated lower oesophageal sphincter relaxation

Background—Atropine decreases the frequency of transient lower oesophageal sphincter relaxation (TLOSR) through an unknown mechanism. Gastric distension and pharyngeal receptor excitation are two possible sources for the afferent stimulus responsible for TLOSR.Aims—To determine whether atropine affects gastric distension induced TLOSR and pharyngeal receptor mediated lower oesophageal sphincter (LOS) relaxation.Methods—Oesophageal manometry and pH recordings were performed in 10 healthy volunteers on two separate days in the postprandial setting, following either atropine (15 μg/kg intravenous bolus and 4 μg/kg/h as a maintenance dose) or placebo. Pharyngeal receptor mediated LOS relaxation was studied in nine subjects by rapid injection of minute amounts of water (0.05, 0.1, 0.2, 0.3, and 0.4 ml) in the pharynx before and after atropine. Gastric distension mediated TLOSR was studied in eight subjects by insufflating the stomach with 300, 600 and 900 ml of CO2 before and after atropine.Results—Atropine reduced the frequency of spontaneous gastro-oesophageal reflux and TLOSR compared with placebo (p<0.05). Pharyngeal stimulation resulted in bolus volume dependent LOS relaxation. Atropine decreased the frequency and amplitude of pharyngeal receptor mediated LOS relaxation at bolus volumes of 0.05, 0.1, and 0.2 ml. Gastric distension resulted in intermittent episodes of TLOSR. The frequency of gastric distension induced TLOSR was significantly decreased by atropine.Conclusion—(1) Atropine reduces the frequency of spontaneous reflux and TLOSR in normal subjects; and (2) gastric distension induced TLOSR and pharyngeal receptor mediated LOS relaxation is inhibited by atropine.

Gestational effects on volume-sensitive cardiopulmonary receptor reflexes in the rat

We tested the hypothesis that augmented reflex sympathoinhibition mediated by volume-sensitive cardiopulmonary (CP) receptors contributes to the vasodilation of pregnancy by comparing responses to acute volume expansion in 21-day-pregnant and age-matched virgin rats (n = 7) that were anesthetized (pentobarbital sodium, 50 mg/kg ip), paralyzed (gallamine triethiodide, 25 mg/kg iv), ventilated, and had undergone bilateral sinoaortic denervation. CP receptors were stimulated with intra-atrial injections of saline (50, 100, 200, and 300 microliter), and the following variables were recorded: 1) mean right atrial pressure (MRAP) to index the afferent stimulus intensity; 2) cell discharge in the nucleus tractus solitarii (NTS), the primary central terminus for CP afferents; and 3) mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) to assess efferent reflex effects. Basal MAP was significantly lower in pregnant (71.5 +/- 3.8 mmHg) than in virgin rats (86.6 +/- 3.1 mmHg), and plasma volume was expanded in the pregnant group (17.6 +/- 1.1 vs. 10.0 +/- 0.7 ml, P < 0.05). Baseline MRAP was similar between groups. Saline injections evoked graded increases in MRAP, which were larger in gravid animals (P < 0.05). Volume injections evoked similar changes in NTS cell discharge between groups, but the responses were nongraded. Despite larger changes in MRAP in gravid rats, reflex effects on RSNA and HR were similar to those in control animals, and effects on MAP were attenuated in the pregnant group. We conclude that larger changes in MRAP in pregnant rats during stimulation of CP receptors are not associated with larger changes in central or efferent components of this reflex.(ABSTRACT TRUNCATED AT 250 WORDS)