Motor responses measured by brain electrical activity mapping.

Studied the brain electrical activity of 14 right-handed normal Ss (mean age 25 yrs) while they were exposed to motor performance tasks of increasing difficulty. Each task lasted 45–60 sec, and a 30-sec period of each task was analyzed by a spectrum analyzer. Data are presented in topographic maps showing the electrical activity for each task, in different frequency bands. Results show a bilateral decrease in amplitude in sensorimotor areas relative to baseline for a single hand movement. Tasks that required the programming of movement showed baseline–task differences in amplitude in additional areas: the right frontal area, the prefrontal area, the posterior parietal area, and the left temporal area. Findings suggest that different topographical areas are involved in motor tasks that require an increased level of programming. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlation between cognitive brain function and electrical brain activity in dementia of Alzheimer type

Enterocytes were detached from various parts of the digestive tract of chickens by treatment with DTT or with hyaluronidase. Isolated enterocytes were exposed to suspensions of the V4 strain of Newcastle disease virus (NDV). Removal of virus from the supernatant fluid was taken as evidence of binding of virus to enterocytes and residual virus was measured both by infectivity assay and by ELISA. Enterocytes from duodenum, jejunum, ileum, caecum, and rectum bound the virus; enterocytes from oesophagus, crop and proventriculus did not.     

Effect of nifedipine on electrical activity of the brain in rat

The anxiolytic effect of the calcium channel blockers nifedipine and verapamil was tested in mice using two test: the conditioned suppression of the motility test and the black and white box test. The nifedipine but not the verapamil, in low doses (0.1 mg/kg b.w), proved anxiolytic effect and both nifedipine and verapamil in high dose (1.6-2.5 mg/kg b.w) had anxiogenic properties. The anxiogenic effect was correlated with the capacity of the drugs to block the calcium channels and the anxiolytic effect of low doses of the nifedipine was considered to be produced by opening these structures. These data were considered important for a new future aboard of the treatment and pathophysiology of the anxiety.     

Effects of pemoline on spontaneous and event-related electrical activity of the brain

The effect of pemoline on the electrical activity of the brain (electroencephalogram, EEG) was studied in relation to time since sleep and time of day in 6 healthy subjects carrying out periods of work lasting 18 h. Power of the spontaneous EEG increased with time since sleep and amplitude of the P3 event-related response decreased. The changes may be interpreted as the reduction in alertness with time awake. In contrast, pemoline decreased power of the spontaneous EEG and increased the amplitude the P3 response, effects that are consistent with improved alertness. The changes in brain activity were paralleled by effects on performance, in terms of percentage of correct responses and reaction time. Performance decreased with time awake, and was improved by pemoline compared with placebo. The drug counteracted the adverse effects of time since sleep, with the beneficial effect of the drug persisting over the 18-hour period of work. The findings emphasise that spontaneous and event-related activity of the EEG may be used both to complement measures of performance in the laboratory and to assess behaviour in occupational situations where performance testing is impractical.     

Baseline asymmetries in brain electrical activity predict dichotic listening performance.

Forty-four right-handed participants were assessed on 2 occasions 6 weeks apart on electrophysiological measures of activation asymmetry derived from spectral estimates of electroencephalogram (EEG) alpha power in homologous scalp electrodes. Approximately 4 months following the final EEG assessment. participants were administered a dichotic listening CV-syllables task. Overall, participants exhibited a highly significant right-ear advantage. Differences among individuals in ear asymmetry were predicted by the earlier recorded electrophysiological data. Participants with greater activation in left-sided posterior temporal and parietal regions showed a larger right-ear advantage. In addition, a larger right-ear advantage was predicted by right-sided prefrontal activation. These data indicate that some of the variance in dichotic listening performance can be explained by dispositional activation asymmetries and is associated with a complex pattern of posterior and anterior activation asymmetries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

模型预测控制器的广义最小方差性能评价

基于滚动时域最小方差性能评价方法和广义最小方差控制原理,提出了可处理约束问题的滚动时域广义最小方差性能评价方法.该性能评价方法既可考虑过程变量的硬约束,同时相对于滚动时域最小方差性能评价方法,又可考虑操纵变量的软约束.基于Wood-Berry精馏塔模型的仿真实例证明了该性能评价方法较滚动时域最小方差性能评价方法具有更高的实际意义,并验证了这种性能评价方法的有效性.     

Functional brain electrical activity mapping in boys with attention-deficit/hyperactivity disorder

BACKGROUND: Symptoms of attention-deficit/hyperactivity disorder (ADHD) have been associated with frontal lobe deficits. We used a novel brain electrical imaging method to investigate rapid and continuous changes in brain activity during the continuous performance task (CPT) in normal boys and in boys with ADHD. The amplitude and latency topography of the steady-state visually evoked potential (SSVEP) were examined while subjects performed the "X" version of the CPT (CPT-X; the reference task) and the "A-X" version of the CPT (CPT-AX). METHODS: Seventeen boys meeting DSM-III-R criteria for ADHD and 17 age-matched controls participated in the study. Brain electrical activity was recorded from 64 scalp sites. During the reference task, subjects pressed a microswitch on the unpredictable appearance of the letter X. During the CPT-AX, subjects were required to press the microswitch on the appearance of the letter X only if an A had preceded it. RESULTS: In the interval between the appearances of the A and the X of the correct trials of the CPT-AX, control boys showed transient reductions in SSVEP latency at right prefrontal sites. By contrast, boys with ADHD showed no change or an increase in prefrontal SSVEP latency at right prefrontal sites. CONCLUSION: Our results suggest increased speed of prefrontal neural processing in children without ADHD following a priming stimulus, and a deficit in such processes in children with ADHD.     

Spatiotemporal imaging of human brain activity using functional MRI constrained magnetoencephalography data: Monte Carlo simulations

The goal of our research is to develop an experimental and analytical framework for spatiotemporal imaging of human brain function. Preliminary studies suggest that noninvasive spatiotemporal maps of cerebral activity can be produced by combining the high spatial resolution (millimeters) of functional MRI (fMRI) with the high temporal resolution (milliseconds) of electroencephalography (EEG) and magnetoencephalography (MEG). Although MEG and EEG are sensitive to millisecond changes in mental activity, the ability to resolve source localization and timing is limited by the ill-posed "inverse" problem. We conducted Monte Carlo simulations to evaluate the use of MRI constraints in a linear estimation inverse procedure, where fMRI weighting, cortical location and orientation, and sensor noise statistics were realistically incorporated. An error metric was computed to quantify the effects of fMRI invisible ("missing") sources, "extra" fMRI sources, and cortical orientation errors. Our simulation results demonstrate that prior anatomical and functional information from MRI can be used to regularize the EEG/MEG inverse problem, giving an improved solution with high spatial and temporal resolution. An fMRI weighting of approximately 90% was determined to provide the best compromise between separation of activity from correctly localized sources and minimization of error caused by missing sources. The accuracy of the estimate was relatively independent of the number and extent of the sources, allowing for incorporation of physiologically realistic multiple distributed sources. This linear estimation method provides an operator-independent approach for combining information from fMRI, MEG, and EEG and represents a significant advance over traditional dipole modeling.     

Regional brain electrical activity in posttraumatic stress disorder after motor vehicle accident.

This study examined whether patients with posttraumatic stress disorder (PTSD) related to motor vehicle accidents (MVAs) would show an abnormal pattern of electroencephalographic (EEG) alpha asymmetries, which has been proposed for particular types of anxiety. Patients with PTSD (n = 22) or subsyndromal PTSD (n = 21), traumatized controls without PTSD (non-PTSD with MVA; n = 21), and healthy controls without MVA (n = 23) underwent measurement of EEG activity during baseline and exposure to a neutral, a positive, a negative, and an accident-related picture. Differences in brain asymmetry between groups were observed only during exposure to trauma-related material. PTSD and subsyndromal PTSD patients showed a pattern of enhanced right anterior and posterior activation, whereas non-PTSD with MVA participants showed the opposite pattern. Furthermore, posterior asymmetry in nontraumatized healthy controls varied with gender, with female participants showing a pattern of higher right posterior activation. The results support the hypothesis that symptomatic MVA survivors are characterized by a pattern of right hemisphere activation that is associated with anxious arousal and symptoms of PTSD during processing of trauma-specific information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of telemetric techniques for use in studies of the electrical activity of the brain

A telemetry system has been designed to transmit two channels of wideband activity (0.2 Hz-2.5 KHz) recorded from high-impedance microelectrodes in the brains of free-moving cats. Thus, both unit activity and slow-wave field activity are accessible without disruption of the animals' behavior. In addition, circuitry is described that conditions the receiver signals, that dicriminates valid subcarrier signals from receiver noise and that automatically aborts data output in the absence of discriminable subcarrier. This receiver signal processing circuitry thus assures the fidelity of the decoded subcarrier, greatly facilitates further machine processing of the data and frees the experimenter from having to continuously monitor the receiver signals to subjectively edit out noisy data.     

A minimum of fuel is necessary for tolbutamide to mimic the effects of glucose on electrical activity in pancreatic beta-cells

Glucose stimulation of pancreatic beta-cells triggers electrical activity (slow waves of membrane potential with superimposed spikes) that is best monitored with intracellular microelectrodes. Closure of ATP-sensitive K+ channels underlies the depolarization to the threshold potential and participates in the increase in electrical activity produced by suprathreshold (>7 mM) concentrations of glucose, but it is still unclear whether this is the sole mechanism of control. This was investigated by testing whether blockade of ATP-sensitive K+ channels by low concentrations of tolbutamide is able to mimic the effects of glucose on mouse beta-cell electrical activity even in the absence of the sugar. The response to tolbutamide was influenced by the duration of the perifusion with the low glucose medium. Tolbutamide (25 microM) caused a rapid and sustained depolarization with continuous activity after 6 min of perifusion of the islet with 3 mM glucose, and a progressive depolarization with slow waves of the membrane potential after 20 min. In the absence of glucose, the beta-cell response to tolbutamide was a transient phase of depolarization with rare slow waves (6 min) or a silent, small, but sustained, depolarization (20 min). Readministration of 3 mM glucose was sufficient to restore slow waves, whereas an increase in the glucose concentration to 5 and 7 mM was followed by a lengthening of the slow waves and a shortening of the intervals. In contrast, induction of slow waves by tolbutamide proved very difficult in the absence of glucose, because the beta-cell membrane tended to depolarize from a silent level to the plateau level, at which electrical activity is continuous. Azide, a mitochondrial poison, abrogated the electrical activity induced by tolbutamide in the absence of glucose, which demonstrates the influence of the metabolism of endogenous fuels on the response to the sulfonylurea. The partial repolarization that azide also produced was reversed by increasing the concentration of tolbutamide, but reappearance of the spikes required the addition of glucose. It is concluded that inhibition of ATP-sensitive K+ channels is not the only mechanism by which glucose controls electrical activity in beta-cells.     

Patterns of brain electrical activity during facial signs of emotion in 10-month-old infants.

This study examined electroencephalogram (EEG) asymmetries during the presence of discrete facial signs of emotion. Thirty-five 10-month-old infants were tested in a standard stranger- and mother-approach paradigm that included a brief separation from their mother. Infant facial expression was videotaped, and brain electrical activity from left and right frontal and parietal regions was recorded. The videotapes were coded with two different discrete facial coding systems. Artifact-free periods of EEG were extracted that were coincident with the expression of the emotions of joy, anger, and sadness. The data revealed different patterns of EEG asymmetry depending on the type of facial expression and vocal expression of affect that was observed. Expressions of joy that involved facial actions of both zygomatic and orbicularis oculi were seen more often in response to mother approach, whereas smiles that did not involve the action of orbicularis oculi were seen more often in response to approach of the stranger. The former type of smile was associated with relative left frontal activation, whereas the latter type was associated with right frontal activation. Facial expressions of anger and sadness exhibited in the absence of crying were associated with left frontal activation, whereas these same facial expressions during crying were associated with right frontal activation. These data underscore the usefulness of EEG measures of hemispheric activation in differentiating among emotional states associated with differences in facial and vocalic expressivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of unconscious interoceptive afferentation on the spatial organization of electrical activity in the human cerebral cortex

Toposcopic studies consisting of EEG recording from 24 cortical points was carried out to characterize the spatial organization of the electrical activity of the human cerebral cortex during the action of unconscious interoceptive stimuli arising from biologically active points associated with different internal organs-the heart, lungs, liver, and intestine. When acupuncture had positive effects, reductions in global synchronization of cortical potentials were noted, which were combined with foci of weakening of the linear and nonlinear correlations in the anterior parts of the right hemisphere, as well as in the posterior and temporal parts of the left hemisphere, with increases in coherence in one of the high-frequency subranges of the EEG (21.5-23.0 Hz). Negative effects and absence of effect correlated with significantly less pronounced weakening of global synchronization of potentials, and increases in their coherence in one of the subranges of alpha activity.     

Individual differences in spatial organization of cortical electrical activity during formation of a set to visual stimuli

Vascular affections of the brain remain a formidable psychiatric challenge nowadays. According to WHO reports cerebrovascular disorders constitute one of the three chief causes of mortality in the population of the economically developed countries of the world. The most important cause of vascular psychoses is considered to be atherosclerosis and hypertensive disease. Today vascular psychoses have become a most common type of abnormal mental states in young adults (greater then 30-40 years old). The studies made have yielded evidence in support of the psychoses morbidity to be dependent upon particular season of year as well as on the climatic features of the locality. Natural factors have been found out to affect the prevalence of vascular psychoses in Chernivtsi Province. The findings obtained suggest to us a substantial prevalence of atherosclerotic and hypertensive psychoses in the plains-men living under conditions of a mild climate.     

Computer programs to analyze brain electrical activity during copulatory pelvic thrusting in male rats

Two microcomputer programs have been developed to simultaneously record and analyze the brain electrical activity: multiple unit activity (MUA) and electroencephalogram (EEG), and the accelerometric signals generated in relation to the pelvic thrusting that performs the male rat during the copulatory responses of mount, intromission, and ejaculation. CAPTUMUL is a program allowing the on line capture of the different signals and the further off line delimitation of the brain signals occurring in exact temporal relation with the accelerometric record of motor responses. The ANAMUA program allows the off line analysis of the neuronal firing rate in MUA records at different discrimination levels according to the amplitude of the neuronal spikes, and compare these data in various behavioral situations. The use of these programs provides a way of correlating in time the changes of brain electrical activity occurring in animals in free-movement with the brief motor events of copulation as well as with other behaviors (i.e., genital grooming, sniffing, running, walking). Advantages of this software include the recording of sequential events, a better and rapid handling of data and a reliable method to analyze the MUA with different discrimination levels according to the amplitude of the neuronal spikes.     

Localization of speech parameters by brain scan

Speech was studied in 18 patients who had a positive radioisotope brain scan within the left hemisphere and a history of a single stroke. Seventeen patients had definite language impariment. In most cases of either fluent or nonfluent aphasia, the center of the scan was behind the central sulcus. Patients with perisylvian involvement were much more likely to have severe comprehension deficit than those without such involvement. Those patients with the most severely decreased fluency were significantly more likely than those more fluent to have markedly decreased comprehension. In an occasional patient, involvement of fluency and comprehension was divergent, suggesting that these processes may be differentially affected.     

Localization of plastic flow: spatial vs temporal instabilities

The initiation of unstable plastic deformation associated with dynamic strain ageing in controlled load rate tests has been studied. Experimental measurements on an AlMgSi alloy show the existence of two regimes of instability: temporal and spatial. The initiation of the instability is found to occur by the growth of spatially uniform (temporal) strain rate oscillations. At a larger strain, spatial strain localization is found to develop. The existence of an intermediate regime of purely temporal instability is confirmed by a (linear) stability analysis, taking into account stress triaxiality due to non-uniform deformation. Interaction between adjacent material elements via dislocation cross-slip is also considered. Both effects are shown to cause a delay in the onset of spatial instabilities relative to purely temporal instabilities.