Cerebral Potentials Research Articles

Signal requirement for cortical potential of transplantable human neuroepithelial stem cells

The cerebral cortex develops from dorsal forebrain neuroepithelial progenitor cells. Following the initial expansion of the progenitor cell pool, these cells generate neurons of all the cortical layers and then astrocytes and oligodendrocytes. Yet, the regulatory pathways that control the expansion and maintenance of the progenitor cell pool are currently unknown. Here we define six basic pathway components that regulate proliferation of cortically specified human neuroepithelial stem cells (cNESCs) in vitro without the loss of cerebral cortex developmental potential. We show that activation of FGF and inhibition of BMP and ACTIVIN A signalling are required for long-term cNESC proliferation. We also demonstrate that cNESCs preserve dorsal telencephalon-specific potential when GSK3, AKT and nuclear CATENIN-β1 activity are low. Remarkably, regulation of these six pathway components supports the clonal expansion of cNESCs. Moreover, cNESCs differentiate into lower- and upper-layer cortical neurons in vitro and in vivo. The identification of mechanisms that drive the neuroepithelial stem cell self-renewal and differentiation and preserve this potential in vitro is key to developing regenerative and cell-based therapeutic approaches to treat neurological conditions.

Vestibular-Evoked Cerebral Potentials.

The human vestibular cortex has mostly been approached using functional magnetic resonance imaging and positron emission tomography combined with artificial stimulation of the vestibular receptors or nerve. Few studies have used electroencephalography and benefited from its high temporal resolution to describe the spatiotemporal dynamics of vestibular information processing from the first milliseconds following vestibular stimulation. Evoked potentials (EPs) are largely used to describe neural processing of other sensory signals, but they remain poorly developed and standardized in vestibular neuroscience and neuro-otology. Yet, vestibular EPs of brainstem, cerebellar, and cortical origin have been reported as early as the 1960s. This review article summarizes and compares results from studies that have used a large range of vestibular stimulation, including natural vestibular stimulation on rotating chairs and motion platforms, as well as artificial vestibular stimulation (e.g., sounds, impulsive acceleration stimulation, galvanic stimulation). These studies identified vestibular EPs with short latency (<20 ms), middle latency (from 20 to 50 ms), and late latency (>50 ms). Analysis of the generators (source analysis) of these responses offers new insights into the neuroimaging of the vestibular system. Generators were consistently found in the parieto-insular and temporo-parietal junction—the core of the vestibular cortex—as well as in the prefrontal and frontal areas, superior parietal, and temporal areas. We discuss the relevance of vestibular EPs for basic research and clinical neuroscience and highlight their limitations.

Direct antivirals and cognitive impairment in hepatitis C: a clinical-neurophysiologic study

Cognition was assessed in hepatitis C virus (HCV) patients, who did not meet the criteria for a minimal hepatic encephalopathy. Their liver function was compensated. We then disentangled potential cognitive changes associated with a sustained virologic response at 12 weeks (SVR-12), following treatment with direct antiviral agents (DAAs). We studied 23 selected HCV patients with a battery of standard neuropsychological tests, and with recordings of the P300 wave, a cerebral potential of “cognitive” significance. There was a baseline evaluation (T0) and a second one 6 months later (T1). We had 2 control groups of comparable age and sex, i.e., 15 patients suffering from non-alcoholic fatty liver disease (NAFLD) and 15 healthy subjects. At T0, we detected a significant (p < 0.05) cognitive impairment in the HCV group, which involved episodic and working memory, attention, visuospatial and verbal abilities, executive functions, and logic reasoning. The P300 latency was significantly (p < 0.05) delayed in the group. At T1, we observed some significant (p < 0.05) HCV recovery in given test domains, e.g., memory, executive functions, and reasoning. Accordingly, the P300 latency shortened significantly (p < 0.05). HCV patients exhibited subtle cognitive defects, somehow independent of their liver condition, possibly linked to direct or indirect brain involvement by the virus. These defects partly recovered following the SVR-12, as achieved through DAAs. The P300 wave was a valid neurophysiologic counterpart of these changes. DAAs can have a role in the early preservation of cognition in HCVs.

Study of long-term mitochondrial dysfunction and oxidative stress in a sepsis-associated encephalopathy model

Objective To investigate the long-term mitochondrial dysfunction and oxidative stress in a sepsis-associated encephalopathy(SAE) model. Methods To initiate experimental sepsis, male Wistar rats were injected intraperitoneally with 10 mg/kg of lipopolysaccharide (LPS) dissolved in sodium chloride.Animals were evaluated by neurologic reflex scores before sacrifice and brain tissues were quickly removed at the indicated time points (0 h for control group and 12, 24, 48, 72 h post injections for SAE groups). Cerebral mitochondrial membrane potential (MMP) and reactive oxygen species(ROS) were detected by flow cytometer and superoxide dismutase(SOD), malondialdehyde(MDA), inducible nitric oxide synthase(iNOS) and nitric oxide(NO) were determined by using microplate reader. Results Deteriorated neurological reflexes were found since 12 h and recovered slowly.Cerebral MMP in 12 h SAE group was decreased significantly compared with that in the control group.MMP was decreased to the lowest level at 48 h (F=75.785, P<0.05), and partly recovered at 72 h .ROS, MDA, iNOS and NO were increased significantly at 48 h (F=111.274, 21.955, 61.076, 21.184, all P<0.05) and partly recovered at 72 h. SOD changed controversially with ROS(F=21.808, P<0.05). SOD showed strong positive linear correlations with MMP(r=0.856, P<0.05), whereas ROS, MDA, iNOS and NO showed strong negative linear correlations with MMP(r=-0.852, -0.890, -0.940, -0.794, all P<0.05). Conclusions These results suggest that long-term brain mitochondrial dysfunction of lipopolysaccharide-induced septic rat is partly affected due to an increase in oxidative stress and has a turning-point near 48 h post injections. Key words: Sepsis-associated encephalopathy; Mitochondrial dysfunction; Oxidative stress; Long-term injury

手指の二点間到達運動における運動意志中断に関連した脳活動

We investigate brain potentials related to the abandonment of the motor intention prior to movement in human volitional finger movement. Subjects are instructed to conduct a point-to-point finger reaching movement with the right index finger. The time to begin this movement is indicated with a clock making one revolution in 4 s. The time at which the clock hand passes the 3 o'clock position is adopted as the go-signal in the go task. In the series of trials, the pre-stop task is conducted with a red light-emitting diode stop-signal presented randomly at 0.1, 0.2, 0.3, 0.4, or 0.5 s before the go-signal. Cerebral potentials at the scalp are recorded using a 20-channel electroencephalography (EEG) system. In the go task without the stop-signal, clear movement-related cortical potentials are observed. In the pre-stop task with the stop-signal, the subjects are able to inhibit finger movement. A positive EEG potential distributed at the midline fronto-central scalp at 300-500 ms after the go-signal is observed only in the pre-stop task. This result suggests that the observed positive component is associated with the interruption of motor intention, as well as the revision of motor planning, in the motor cortices prior to the movement.

104. Multiparametric neurophysiological assessment in Neonatal-ICU: Methodology and registration technique

Standardise an Integrated Multiparametric Neurophysiological Assessment (IMNA) simultaneously recording Video-EEG (VEEG), Cascade-Somatosensory-Evocated-Potentials (CSEPs), Cerebral-Function-Monitoring (CFM) and Density-Spectral-Analysis (DSA); to a complete data’s temporal correlation, using the advantages of each recording. We performed 1 h-short-monitoring-IMNA in 98 newborns (71 fullterms-27 preterms) in Neonatal-ICU; respecting SEPs-topographic derivation cerebral potentials were recorded from front-central-temporal-occipital areas, including the cervical and usual polygraphic ones. We used EBneuro monitoring-device (NeMus2-acquisition-stimulation-hardware, ICU.NET-software), disposable surface-recording electrodes (Ambu-Neuroline), surface-small-size cup (3 mm) AgCl-electrodes (BIONEN), abrasive-gel and conductive-cream (TEN20). The acquisition-panel is composed of modular-windows in demand: VEEG-recording (8bipolar-channels Fp2-C4;C4-O2;Fp2-T4;T4-O2;Fp1-C3;C3-O1;Fp1-T3;T3-O1); parameters (0.3 s;70 Hz;10 μV/mm); impedences <10 KΩ. 4bipolars-channels-CFM (scale 20–120 μV)-DSA (visible stripe 0–32 Hz, color-map-interval 0–10 μV2) extrapolated from the EEG-montage. CSEPs (N1–N13 components) in sequence (Cc-Fz;Cc-Ci;Cv7-Fz) obtained by bilaterally alternated-1 Hz-stimulus from median nerve (200 ms;10–20 mA; 50 average), referred to the template-potential. CSEP’s components in trends. 1 h-short-monitoring-IMNA was able to identify a neonate’s sleep-cycle and well tolerated from the newborns (95%), with truthful registrations. IMNA-monitoring was easily performed in Neonatal-ICU, obtaining well recognizable, reliable, on–off-line assessible data, in particular CSEP. This new assessment, using 2 electrodes (Fz-Cv7) and 2 stimulatories in addition respect of the traditional VEEG, is useful to obtain more instrumental data in a little extra-time, extending the neurological informations in Neonatal-ICU.

Brain activity evoked by motor inhibition before volitional finger movement

The present study investigated the brain activity that accompanied motor inhibition before movement in human volitional finger movement. Seven individuals were instructed to press a force sensor with the right index finger. The time to begin this movement was indicated with a clock making a 4-s revolution. The time at which the clock hand passed the 3 o'clock position was adopted as the go-signal in the go task. In the series of trials, the task, we designated as prestop task, was performed with a red light-emitting diode stop-signal presented randomly at 0.1, 0.2, 0.3, 0.4, or 0.5 s before the go-signal. Cerebral potentials from the scalp were recorded using a 20-channel electroencephalography system. In the go task without the stop-signal, clear movement-related cortical potentials were observed. In the prestop tasks with the stop-signal, the participants were able to inhibit finger movement. A positive electroencephalography potential distributed at the midline frontocentral scalp 400 ms after the stop-signal was observed only in the prestop task. This suggests that the observed positive component is associated with the interruption of motor intent, as well as the revision of motor planning, in the motor cortices before the movement.

The effects of neck flexion on cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in related sensory cortices

BackgroundA flexed neck posture leads to non-specific activation of the brain. Sensory evoked cerebral potentials and focal brain blood flow have been used to evaluate the activation of the sensory cortex. We investigated the effects of a flexed neck posture on the cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in the related sensory cortices.MethodsTwelve healthy young adults received right visual hemi-field, binaural auditory and left median nerve stimuli while sitting with the neck in a resting and flexed (20° flexion) position. Sensory evoked potentials were recorded from the right occipital region, Cz in accordance with the international 10–20 system, and 2 cm posterior from C4, during visual, auditory and somatosensory stimulations. The oxidative-hemoglobin concentration was measured in the respective sensory cortex using near-infrared spectroscopy.ResultsLatencies of the late component of all sensory evoked potentials significantly shortened, and the amplitude of auditory evoked potentials increased when the neck was in a flexed position. Oxidative-hemoglobin concentrations in the left and right visual cortices were higher during visual stimulation in the flexed neck position. The left visual cortex is responsible for receiving the visual information. In addition, oxidative-hemoglobin concentrations in the bilateral auditory cortex during auditory stimulation, and in the right somatosensory cortex during somatosensory stimulation, were higher in the flexed neck position.ConclusionsVisual, auditory and somatosensory pathways were activated by neck flexion. The sensory cortices were selectively activated, reflecting the modalities in sensory projection to the cerebral cortex and inter-hemispheric connections.

Brain Responses to Cardiac Electrical Stimulation: A New EEG Method for Evaluating Cardiac Sensation

Although cardiac sensation, such as palpitation or chest pain, is common and is sometimes a malignant sign of heart diseases, the mechanism by which the human brain responds to afferent signals from the heart remains unclear. In this study, we investigated whether electrical stimulation of the heart provokes brain responses in humans. We examined 15 patients (age: 65.4 ± 3.1 years old, 11 males and 4 females) implanted with either a cardiac pacemaker or cardiac resynchronization therapy (CRT) device. Electroencephalogram (EEG) was simultaneously recorded from the vertex during right ventricular pacing at 70-100 beats/min at baseline (1.5 V) and intense (6-8 V) stimulation sessions. We evaluated brain responses to cardiac electrical stimulation by measuring cerebral potentials that were obtained by subtracting the average of 100 EEG waves triggered by cardiac pacing during baseline stimulation from those during the intense stimulation. Intense stimulation of the cardiac pacemaker or CRT device reproducibly induced cardiac sensation in 6 out of the 15 patients; namely, the remaining 9 patients showed no reproducible response. Brain responses were evident by averaging cerebral potentials from all of the 15 patients and those from 6 patients with reproducible cardiac sensation. To the best our knowledge, this is the first report that demonstrates the brain responses to cardiac electrical stimulation in humans. This new method should be useful for examining pathophysiology of cardiac diseases with pathological cardiac sensation, including cardiac anxiety and silent myocardial ischemia.

Features of the organization of the cerebral cortex bioelectric potentials and visceral state in neurotic depression

Studies were conducted with the participation of 20 patients with different classical variants of neurotic depression. The spatial organization of the bioelectrical activity of the brain was studied with the method of cross-correlation and coherent analysis. The autonomic-visceral state was assessed by the results of the auricular cryoreflex test (measurement of the cold sensibility of auricular points). The clinical picture of neurotic depression was shown to be reflected in the structure of the EEG spatial organization, which is modified depending on the degree of neurotic depression and the concomitant anxiety and asthenic syndromes. In the group with depressive syndrome without concomitant asthenic or anxiety manifestations, most changes were revealed in the right frontotemporal-left posterotemporal region. A cross-correlation and coherence decrease in the frontotemporal regions of both hemispheres and markedly increased cross-correlations in the right posterotemporal region were revealed in the depression + associated anxiety group. In the group where the depressive and anxiety syndromes were associated with marked asthenic manifestations, decreased cross-correlation and coherent relations in the frontotemporal regions of both hemispheres were observed. The clinical picture of neurotic disorders is reflected in a specific pattern of variations in the spatial organization of electrical activity of the cerebral cortex and in variations in the autonomic visceral state parameters. The development of negative emotional states in humans is accompanied by changes in the visceral functions. Variations in the central brain structures involve the zones of representation of emotional reactions and the zones of cortical representation of the organs. Insignificant central variations may cause autonomic dysfunction.

Facial emotion triggered cerebral potentials in treatment-resistant depression and borderline personality disorder patients of both genders

Processing facial expressions of emotion is deteriorated in depression, which might be more pronounced in treatment-resistant depression (TRD), especially when the latter is comorbid with borderline personality disorder (BPD). Neurophysiologically, both early perceptual and late cognitive cerebral processes of facial emotions can be illustrated by event-related potentials (ERPs). We therefore tried the ERPs to facial expressions of Neutral, Anger, Happiness, and Sadness in 25 patients with TRD, 15 with BPD, 22 with their comorbidity (TRD+BPD), as well as in 37 healthy volunteers. The depression levels of participants were measured with the Plutchik-van Praag Depressive Inventory (PVP). There was no group difference regarding either N1 (N170), P2, N2, P3a or P3b latency or amplitude to the four facial emotions. Reaction times (RTs) to Anger (p<.01), Happiness (p<.01), and Sadness (p<.001) in TRD, and those to Anger (p<.01) and Happiness (p<.01) in TRD+BPD patients were longer than those in the healthy volunteers. RTs to the four facial expressions were positively correlated (p<.01) with their depressive moods in all participants. In addition, PVP was positively correlated with the P2 latency to Anger in TRD+BPD patients (Fz, p<.01; Cz, p<.01; Pz, p<.01). BPD contributed little to TRD or TRD+BPD regarding cerebral processing of facial emotions, however, other cognitive and behavioral data suggest a generalized impairment when responding to facial emotions in TRD and TRD+BPD patients, and a deteriorated perceptual processing of Anger in TRD+BPD patients.

Paracetamol and opioid pathways: a pilot randomized clinical trial

Previous studies suggest that the antinociceptive action of paracetamol (acetaminophen, APAP) might involve descending inhibitory pain pathways and the opioidergic system: this study explores this issue in humans with naloxone, the opioid antagonist. After ethical approval, 12 healthy male volunteers were included in this randomized, controlled, double-blind, crossover, four-arm study. They were administered intravenous paracetamol (APAP 1 g) or saline (placebo, pl) followed at 100 min with IV naloxone (Nal 8 mg) or saline, every week for 4 weeks. The amplitude of cerebral potentials evoked by thermal/painful stimuli applied on the arm was recorded nine times over 150 min, witnessing of pain integration at central level. Amplitude changes as well as areas under the curve (AUCs) over 150 min were compared for the four treatments by repeated measures ANOVA (significance 0.05). Amplitude changes were significant for APAP/pl vs. pl/pl at t150: -44% (95%CI -58 to -30) vs. -27% (95%CI -37 to -17; P < 0.05) but not vs. APAP/Nal. AUC (0-150) of APAP/pl is significantly different from pl/pl (-3452%.min (95%CI -4705 to -2199) vs. -933% min (95%CI -2273 to 407; P = 0.015) but not from APAP/Nal (-1731% min (95%CI -3676 to 214; P = 0.08) and other treatments. AUC (90-150) is not significantly different. This pilot study shows for the first time in human volunteers that naloxone does not inhibit paracetamol antinociception, suggesting no significant implication of the opioid system in paracetamol mechanism of action: this needs be confirmed on a larger number of subjects.

Functional MRI brain imaging studies using the Contact Heat Evoked Potential Stimulator (CHEPS) in a human volunteer topical capsaicin pain model

Acute application of topical capsaicin produces spontaneous burning and stinging pain similar to that seen in some neuropathic states, with local hyperalgesia. Use of capsaicin applied topically or injected intradermally has been described as a model for neuropathic pain, with patterns of activation in brain regions assessed using functional magnetic resonance imaging (fMRI) and positron emission tomography. The Contact Heat Evoked Potential Stimulator (CHEPS) is a noninvasive clinically practical method of stimulating cutaneous A-delta nociceptors. In this study, topical capsaicin (1%) was applied to the left volar forearm for 15 minutes of twelve adult healthy human volunteers. fMRI scans and a visual analog pain score were recorded during CHEPS stimulation precapsaicin and postcapsaicin application. Following capsaicin application there was a significant increase in visual analog scale (mean ± standard error of the mean; precapsaicin 26.4 ± 5.3; postcapsaicin 48.9 ± 6.0; P < 0.0001). fMRI demonstrated an overall increase in areas of activation, with a significant increase in the contralateral insular signal (mean ± standard error of the mean; precapsaicin 0.434 ± 0.03; postcapsaicin 0.561 ± 0.07; P = 0.047). The authors of this paper recently published a study in which CHEPS-evoked A-delta cerebral potential amplitudes were found to be decreased postcapsaicin application. In patients with neuropathic pain, evoked pain and fMRI brain responses are typically increased, while A-delta evoked potential amplitudes are decreased. The protocol of recording fMRI following CHEPS stimulation after topical application of capsaicin could be combined with recording of evoked potentials to provide a simple, rapid, and robust volunteer model to develop novel drugs for neuropathic pain.

ERP evidence for selective drop in attentional costs in uncertain environments: Challenging a purely premotor account of covert orienting of attention

Several studies have proved that the reliability of endogenous spatial cues linearly modulates the reaction time advantage in the processing of targets at validly cued vs. invalidly cued locations, i.e. the “validity effect”. This would imply that with non-predictive cues, no “validity effect” should be observed. However, contrary to this prediction, one could hypothesize that attentional benefits by valid cuing (i.e. the RT advantage for validly vs. neutrally cued targets) can still be maintained with non-predictive cues, if the brain were endowed with mechanisms allowing the selective reduction in costs of reorienting from invalidly cued locations (i.e. the reduction of the RT disadvantage for invalidly vs. neutrally cued targets). This separated modulation of attentional benefits and costs would be adaptive in uncertain contexts where cues predict at chance level the location of targets. Through the joint recording of manual reaction times and event-related cerebral potentials (ERPs), we have found that this is the case and that relying on non-predictive endogenous cues results in abatement of attentional costs and the difference in the amplitude of the P1 brain responses evoked by invalidly vs. neutrally cued targets. In contrast, the use of non-predictive cues leaves unaffected attentional benefits and the difference in the amplitude of the N1 responses evoked by validly vs. neutrally cued targets. At the individual level, the drop in costs with non-predictive cues was matched with equivalent lateral biases in RTs to neutrally and invalidly cued targets presented in the left and right visual field. During the cue period, the drop in costs with non-predictive cues was preceded by reduction of the Early Directing Attention Negativity (EDAN) on posterior occipital sites and by enhancement of the frontal Anterior Directing Attention Negativity (ADAN) correlated to preparatory voluntary orienting. These findings demonstrate, for the first time, that the segregation of mechanisms regulating attentional benefits and costs helps efficiency of orienting in “uncertain” visual spatial contexts characterized by poor probabilistic association between cues and targets.

Somatosensory evoked potential from S1 nerve root stimulation

The objective of this study was to detect cerebral potentials elicited by proximal stimulation of the first sacral (S1) nerve root at the S1 dorsal foramen and to investigate latency and amplitude of the first cerebral potential. Tibial nerve SEP and S1 nerve root SEP were obtained from 20 healthy subjects and 5 patients with unilateral sciatic nerve or tibial nerve injury. Stimulation of the S1 nerve root was performed by a needle electrode via the S1 dorsal foramen. Cerebral potentials were recorded twice to document reproducibility. Latencies and amplitudes of the first cerebral potentials were recorded. Reproducible cerebral evoked potentials were recorded and P20s were identified in 36 of 40 limbs in the healthy subjects. The mean latency of P20 was 19.8 ± 1.6 ms. The mean amplitude of P20-N30 was 1.2 ± 0.9 μV. In the five patients, P40 of tibial nerve SEP was absent, while well-defined cerebral potentials of S1 nerve root SEP were recorded and P20 was identified from the involved side. This method may be useful in detecting S1 nerve root lesion and other disorders affecting the proximal portions of somatosensory pathway. Combined with tibial nerve SEP, it may provide useful information for diagnosis of lesions affecting the peripheral nerve versus the central portion of somatosensory pathway.

Initiating inspiration outside the medulla does produce eupneic breathing

ARTERIAL PCO2 IS DICTATED by the ratio between the level of pulmonary gas exchange and alveolar ventilation (VA), not minute ventilation. If so, how could isocapnia be maintained if only the magnitude (tidal volume, VT) and duration (TI and TTOT) of the neural output produced by the central pattern generator of breathing (CPG) can be altered? In other words, what is the strategy used by the respiratory control system to match its output to the level of pulmonary gas exchange to keep arterial blood gas homeostasis if this neural output con- tributes to dead space ventilation? In this Viewpoint, we will show that when the spontaneous breathing is replaced by a cortically triggered breathing pattern at various breathing frequencies (we will name this new rhythm an "ecto-rhythm"), the relationship between TTOT and VT has a positive intercept that averages the pulmonary dead space. As a result, the coupling between ventilation and the pulmonary gas exchange becomes possible (17). We will present the idea that whenever isocapnia is maintained during spontaneous or automatic breathing, the magnitude and dura- tion of breath cycles must display the same relationship as during an ecto-rhythm (15). Conversely, we will discuss the implications of the observation that breathing can display the same essential regulatory properties whether generated outside or within the pontomedullary CPG area (7). Ecto-rhythm, breathing pattern, and gas exchange: the re-

Genetic and social factors in the development of aggression

The effect of the variants of the serotonin transporter gene (5-HTT) on aggressiveness was studied in male and female control subjects and athletes. Sports were found to generally decrease aggressiveness; this was true both for women doing nonaggressive sports and for men doing combat sports. The control group of men was characterized by higher indices of aggressiveness (physical and verbal aggression, negativism, and suspiciousness) than women were. Women, irrespective of age and whether they participated in sports, exhibited a relationship between 5-HTT gene variants and the displaced aggressiveness and negativism scales: the SS genotype was associated with a higher displaced aggressiveness and a low negativism. Men exhibited a different relationship. The general aggressiveness index was significantly higher in carriers of the LL genotype than in carriers of the SS genotype, whereas these subjects did not differ significantly in the parameters measured by individual scales. In men, the cerebral processes that are presumed to underlie aggressiveness were found to be related to 5-HTT gene variants. The HP component of the cerebral potential responsible for automatic detection of differences was increased and the P3a component responsible for involuntary attention and cognitive control. This suggests that carriers of the SS genotype use more cognitive resources to process information. This may be because the stimulus itself seems to be more “complex,” which results in the involvement of additional resources of the frontal cortex. It may also be assumed that carriers of the SS genotype tend to analyze the incoming information more deeply. This, more “serious” analysis of external information may underlie their refraining from impulsive behavior, which is often aggressive.

The level of cerebral DC potentials in children with attention deficit-hyperactivity disorder

The level of cerebral DC potentials (LDCPs) was studied in 92 healthy children aged seven to eight years and 39 age-matched children with attention deficit-hyperactivity disorder. Analysis of the distribution of the LDCPs was carried out by mapping the DC potentials obtained using monopolar measurement and calculating deviations in each of the derivations from the average values recorded in all the regions of the head. The characteristic features of the distribution of the LDCPs in children aged seven to eight years with attention deficit-hyperactivity disorder, such as a decrease in the total DC potential value, a sharp decrease in the level of DC potentials in the frontal region, a decrease in their relations with the LDCP of other cerebral structures, and changes in the interhemispheric asymmetry were found.

Are There Nociceptive-Specific Brain Potentials?

to the editor: In their study on factor analysis of brain responses to different stimulus modalities, [Mouraux and Iannetti (2009)][1] claimed that laser-evoked brain potentials do not reflect nociceptive-specific neural activity, although laser radiant heat pulses provide a purely nociceptive input

Correlations of the Peculiarities of the Motivational Sphere and Characteristics of Event-Related EEG Potentials in Humans

We studied the relations between generalized characteristics of the state of the motivational sphere, the levels of need for achievements (N-Ach) and achievement motivation (AchM) typical of an individual, and the parameters of cerebral event-related potentials (ERPs). The examined group included 70 adults of both sexes. The ERPs were recorded in the course of realization of two behavioral test acts with motor components. In task А, the subject should press a button with the minimum delay with respect to an imperative signal preceded by a warning signal (with the measurement of the time of sensorimotor reaction); in this case, the contingent negative variation (CNV) and Р300 potential were recorded. Under conditions of task B, the subject should measure a definite time interval limiting the latter by two pushings of the button; in this case, the readiness potential (RP) was recorded in addition to CNV and Р300. The ERPs were recorded in the С3 and С4 leads (according to the 10-20 system). The peculiarities of the motivational sphere were diagnosed using Orlov’s and Mechrabian’s questionnaires. We found that a relatively high amplitude of the early CNV component (СNV-O) and low amplitudes of the integral CNV and Р300 in task A and a low amplitude of the RP can serve as task B-related EEG markers of a high NA level. In task A, high levels of the AchM correlated with higher amplitudes of the CNV and Р300, and amplitudes of these potentials were higher in the left hemisphere. The observed interrelations were probably determined by a considerable dependence of the N-Ach and AchM characteristics, on the one hand, and CNV amplitude parameters, on the other hand, on the hereditary factors, in particular neurochemical ones. It is obvious that such peculiarities of the neurodynamic constitution of an individual are, to a considerable extent, determined by the specificity of organization and functioning of a few neurotransmitter (in particular aminergic) and neurohumoral systems.