Fronto-central Regions Research Articles

Focal negative motor seizures: Multimodal evaluation.

This case report shows the importance of multimodal evaluation to formulate a proper diagnosis of negative motor seizures (NMSs). Only few reports in literature document NMSs with video-electroencephalographic (EEG) and electromyographic coregistration. A multimodal evaluation is crucial to exclude common mimics and propose correct therapy. We describe a case of a 62-year-old man with drug-resistant focal epilepsy and NMSs, evaluated with video-EEG recording with polygraphy, magnetoencephalography (MEG), and brain magnetic resonance imaging (MRI). Video-EEG monitoring showed 182 focal NMSs, with preserved awareness and comprehension. The patient reported complex paresthesia of the left hand followed by left facial grimace, left arm flaccid paralysis, and bradycardia. EEG showed ictal discharges in the right frontocentral region associated with sudden electromyographical silence in left limb muscles consistent with loss of tonic contraction from distal to proximal muscles of the arm. MEG localized the epileptic zone in the right opercular region, consistent with MRI evidence of type II cortical dysplasia in the right inferior frontal gyrus. Multimodal evaluation is essential to document the temporal relationship between ictal discharges, clinical onset of limb paresis, and electrophysiologic evidence of loss of tonic muscular contraction. It allows definition of the specific cortical area involved in NMSs, offering new insight into physiological brain functioning.

EEG oscillations in recent suicide attempters: Assessing responses to positive and negative future imagination tasks

BackgroundOur goal is to uncover Electroencephalography (EEG) power spectrum patterns during imagination tasks in individuals who attempted suicide within the past 1–4 weeks, addressing gaps in understanding the neural correlates of future imagination in suicidal behavior. MethodsThis case-control study comprised a total of 60 participants, consisting of 47 females and 13 males. The sample comprised three groups: Attempted Suicide + Major Depressive Disorder (SA+MDD), Major Depressive Disorder (MDD), and Healthy Controls (HC). To assess participants' future imagination, a unique approach called the Positive and Negative Future Imagination Task was designed, which involved scenario visualization concurrent with EEG recording. Statistical analyses included ANOVA with post-hoc pairwise comparisons to compare EEG power spectrum between three groups. ResultsIt was observed that the SA+MDD group experienced significantly increased theta frequency band in the right frontocentral regions when compared to the MDD group during both positive and negative imagination tasks (P-value < 0.05). Furthermore, increased gamma activity was observed in the SA+MDD group compared to the HC group, predominantly in the right frontocentral areas during both imagination tasks. ConclusionThe results of this study indicate that individuals who have recently attempted suicide exhibit heightened neural activity in the frontocentral regions of the right hemisphere of the brain, specifically in theta and gamma band frequencies, when contemplating both positive and negative aspects of the future. These findings, in the context of behavioral tasks may indicate a decrease in the ability to envision a positive future and an increase in visualizing a negative future.

Cross-Task Differences in Frontocentral Cortical Activations for Dynamic Balance in Neurotypical Adults.

Although significant progress has been made in understanding the cortical correlates underlying balance control, these studies focused on a single task, limiting the ability to generalize the findings. Different balance tasks may elicit cortical activations in the same regions but show different levels of activation because of distinct underlying mechanisms. In this study, twenty young, neurotypical adults were instructed to maintain standing balance while the standing support surface was either translated or rotated. The differences in cortical activations in the frontocentral region between these two widely used tasks were examined using electroencephalography (EEG). Additionally, the study investigated whether transcranial magnetic stimulation could modulate these cortical activations during the platform translation task. Higher delta and lower alpha relative power were found over the frontocentral region during the platform translation task when compared to the platform rotation task, suggesting greater engagement of attentional and sensory integration resources for the former. Continuous theta burst stimulation over the supplementary motor area significantly reduced delta activity in the frontocentral region but did not alter alpha activity during the platform translation task. The results provide a direct comparison of neural activations between two commonly used balance tasks and are expected to lay a strong foundation for designing neurointerventions for balance improvements with effects generalizable across multiple balance scenarios.

Listen to the beat: Behavioral and neurophysiological correlates of slow and fast heartbeat sounds

BackgroundListening to heartbeat sounds have been found to affect cardiac activity and behavior. However, less is known about the effects of these stimuli on brain activity and cognition. Alpha oscillations (8–13 Hz) are considered markers of cortical activation. Frontal alpha Asymmetry (FαA) reflects the valence attributed to the stimulus and the tendency to approach/avoid it. AimThis study investigates the effects of sounds mimicking heart pulsations at different rhythms on reaction times and neurophysiological activity. MethodEEG data were collected during a resting-state condition and two Simple Reaction Time tasks (SRT), during which artificially generated heartbeat sounds at fast (120 bpm, FastBeat condition) or slow (60 bpm, SlowBeat condition) rhythms were administered. Alpha power was compared across the three conditions. Differences in the SRT and FαA values were examined between the FastBeat and SlowBeat conditions. ResultsCompared to the resting-state condition, decreased alpha activity over bilateral frontocentral regions was observed in both tasks. The comparison between the FastBeat and the SlowBeat conditions revealed faster response times, a pattern of alpha suppression over right frontal regions, and lower FαA values in the former. ConclusionsThe similarity of alpha reductions elicited in the comparison between the resting-state and the two task conditions suggests that these patterns were ascribable to processes common to both conditions (SRT task, auditory stimulation). In contrast, the differences between the two conditions suggest that fast heartbeat sounds are perceived as more adverse and stressful stimuli, inducing cortical activation over regions associated with negative states and avoidant tendencies.

Enhancing motor skill learning through multiple sessions of online high-definition transcranial direct current stimulation in healthy adults: insights from EEG power spectrum.

The purpose of this study was to evaluate the influence of high-definition transcranial direct current stimulation (HD-tDCS) on finger motor skill acquisition. Thirty-one healthy adult males were randomly assigned to one of three groups: online HD-tDCS (administered during motor skill learning), offline HD-tDCS (delivered before motor skill learning), and a sham group. Participants engaged in a visual isometric pinch task for three consecutive days. Overall motor skill learning and speed-accuracy tradeoff function were used to evaluate the efficacy of tDCS. Electroencephalography was recorded and power spectral density was calculated. Both online and offline HD-tDCS total motor skill acquisition was significantly higher than the sham group (P < 0.001 and P < 0.05, respectively). Motor skill acquisition in the online group was higher than offline (P = 0.132, Cohen's d =1.46). Speed-accuracy tradeoff function in the online group was higher than both offline and sham groups in the post-test. The online group exhibited significantly lower electroencephalography activity in the frontal, fronto-central, and centro-parietal alpha band regions compared to the sham (P < 0.05). The findings suggest that HD-tDCS application can boost finger motor skill acquisition, with online HD-tDCS displaying superior facilitation. Furthermore, online HD-tDCS reduces the power of alpha rhythms during motor skill execution, enhancing information processing and skill learning efficiency.

What Chemsex does to the brain - neural correlates (ERP) regarding decision making, impulsivity and hypersexuality.

Chemsex describes the use of specific substances (methamphetamine, GHB/GBL, mephedrone, ketamine) which initiate or enhance sexual experiences and is mainly prevalent among men who have sex with men. Many Chemsex users experience somatic complications (for example sexually transmitted diseases) and sometimes adverse sociological, psychological, and neurological symptoms, such as depression, impulse control disorders or hypersexuality. Changes in impulsivity and deficits in executive functions have demonstrated to be associated with addiction and impulse control disorders as well as frontal brain dysfunction and behavioral control deficits. This study aims to explore the effects of neurophysiological correlates of inhibition and decision making in Chemsex users with an EEG paradigm using event-related potentials (N2, P3). 15 Chemsex users and 14 matched control subjects, all of them men who have sex with man, participated in an auditory Go/NoGo/Voluntary Selection EEG paradigm. In addition, clinical data (e.g. regarding depression), demographic information as well as measures of well-being and sexual behavior were collected. The results demonstrated that clinical symptoms, hypersexuality, and sexual risk behavior were more pronounced in Chemsex users compared to non-users. P3 amplitudes did not differ significantly between groups. However, the Chemsex users showed decreased electrophysiological N2 responses in fronto-central brain regions during decision-making, indicating compromised executive function and inhibitory control. The observed impairments may lead to increased risk behavior regarding drug abuse and hypersexuality. Understanding the neurobiological mechanisms can contribute to targeted interventions in order to mitigate the negative consequences of engaging in Chemsex and improve general well-being.

The human brain deals with violating general color or depth knowledge in different time courses

Utilizing the high temporal resolution of event-related potentials (ERPs), we compared the time course of processing incongruent color versus 3D-depth information. Participants were asked to judge whether the food color (color condition) or 3D structure (3D-depth condition) was congruent or incongruent with their previous knowledge and experience. The behavioral results showed that the reaction times in the congruent 3D-depth condition were slower than those in the congruent color condition. The reaction times in the incongruent 3D-depth condition were slower than those in the incongruent color condition. The ERP results showed that incongruent color stimuli induced a larger N270, larger P300, and smaller N400 components in the fronto-central region than the congruent color stimuli. Incongruent 3D-depth stimuli induced a smaller N1 in the occipital region, larger P300 and smaller N400 in the parietal-occipital region than congruent 3D-depth stimuli. The time–frequency analysis found that incongruent color stimuli induced a larger theta band (360–580 ms) activation in the fronto-central region than congruent color stimuli. Incongruent 3D-depth stimuli induced larger alpha and beta bands (240–350 ms) activation in the parietal region than congruent 3D-depth stimuli. Our results suggest that the human brain deals with violating general color or depth knowledge in different time courses. We speculate that the depth perception conflict was dominated by solving the problem with visual processing, whereas the color perception conflict was dominated by solving the problem with semantic violation.

Intranasal Oxytocin Improves Interoceptive Accuracy and Heartbeat-Evoked Potentials During a Cardiac Interoceptive Task

BackgroundInteroception represents perception of the internal bodily state, which is closely associated with social/emotional processing and physical health in humans. Understanding the mechanism that underlies interoceptive processing, particularly its modulation, is therefore of great importance. Given the overlap between oxytocinergic pathways and interoceptive signaling substrates in both peripheral visceral organs and the brain, intranasal oxytocin administration is a promising approach for modulating interoceptive processing. MethodsUsing a double-blind, placebo-controlled, between-participant design, we recruited 72 healthy male participants who performed a cardiac interoceptive task during electroencephalograph and electrocardiograph recording to examine whether intranasal administration of the neuropeptide oxytocin could modulate interoceptive processing. We also collected data in a resting state to examine whether we could replicate previous findings. ResultsThe results showed that in the interoceptive task, oxytocin increased interoceptive accuracy at the behavioral level, which was paralleled by larger heartbeat-evoked potential amplitudes in frontocentral and central regions on the neural level. However, there were no significant effects of oxytocin on electroencephalograph or electrocardiograph during resting state. ConclusionsThese findings suggest that oxytocin may only have a facilitatory effect on interoceptive processing under task-based conditions. Our findings not only provide new insights into the modulation of interoceptive processing via targeting the oxytocinergic system but also provide proof-of-concept evidence for the therapeutic potential of intranasal oxytocin in mental disorders with dysfunctional interoception.

Lower Childhood Socioeconomic Status Is Associated with Greater Neural Responses to Ambient Auditory Changes in Adulthood.

Humans' early life experience varies by socioeconomic status (SES), raising the question of how this difference is reflected in the adult brain. An important aspect of brain function is the ability to detect salient ambient changes while focusing on a task. Here, we ask whether subjective social status during childhood is reflected by the way young adults' brain detecting changes in irrelevant information. In two studies (total n = 58), we examine electrical brain responses in the frontocentral region to a series of auditory tones, consisting of standard stimuli (80%) and deviant stimuli (20%) interspersed randomly, while participants were engaged in various visual tasks. Both studies showed stronger automatic change detection indexed by MMN in lower SES individuals, regardless of the unattended sound's feature, attended emotional content, or study type. Moreover, we observed a larger MMN in lower-SES participants, although they did not show differences in brain and behavior responses to the attended task. Lower-SES people also did not involuntarily orient more attention to sound changes (i.e., deviant stimuli), as indexed by the P3a. The study indicates that individuals with lower subjective social status may have an increased ability to automatically detect changes in their environment, which may suggest their adaptation to their childhood environments.

Socioeconomic Inequalities Affect Brain Responses of Infants Growing Up in Germany.

Developmental changes in functional neural networks are sensitive to environmental influences. This EEG study investigated how infant brain responses relate to the social context that their families live in. Event-related potentials of 255 healthy, awake infants between six and fourteen months were measured during a passive auditory oddball paradigm. Infants were presented with 200 standard tones and 48 randomly distributed deviants. All infants are part of a longitudinal study focusing on families with socioeconomic and/or cultural challenges (Bremen Initiative to Foster Early Childhood Development; BRISE; Germany). As part of their familial socioeconomic status (SES), parental level of education and infant's migration background were assessed with questionnaires. For 30.6% of the infants both parents had a low level of education (≤10 years of schooling) and for 43.1% of the infants at least one parent was born abroad. The N2-P3a complex is associated with unintentional directing of attention to deviant stimuli and was analysed in frontocentral brain regions. Age was utilised as a control variable. Our results show that tone deviations in infants trigger an immature N2-P3a complex. Contrary to studies with older children or adults, the N2 amplitude was more positive for deviants than for standards. This may be related to an immature superposition of the N2 with the P3a. For infants whose parents had no high-school degree and were born abroad, this tendency was increased, indicating that facing multiple challenges as a young family impacts on the infant's early neural development. As such, attending to unexpected stimulus changes may be important for early learning processes. Variations of the infant N2-P3a complex may, thus, relate to early changes in attentional capacity and learning experiences due to familial challenges. This points towards the importance of early prevention programs.

Neural tracking of natural speech in children in relation to their receptive speech abilities

Receptive speech is the ability to understand speech addressed to a person. It is a crucial process for a child’s cognitive development. We examine the relationship between receptive speech and neural tracking of natural speech in 52 children aged 3–8 years to infer the neurophysiological mechanisms underlying speech development. We registered a 32-channel electroencephalogram (EEG) while children listened to narrative audio stories. The temporal response function (TRF) approach was used to study neural tracking features at acoustic and semantic levels. We found a strong positive correlation between the TRF prediction accuracy values that demonstrate the magnitude of neural tracking, and receptive speech abilities measured by the Preschool Language Scales (PLS-5). Topographic analysis of these correlations showed significant clusters of EEG channels in the right temporal region for acoustic tracking, and in the left fronto-central and right parieto-occipital regions for semantic tracking. We assume that these results reflect the development of the brain systems necessary for speech comprehension. To sum up, we suggest that the TRF measures are easy-to-assess neurophysiological markers of receptive speech development in children.

Differences in scalp-to-cortex tissues across age groups, sexes and brain regions: Implications for neuroimaging and brain stimulation techniques

Aging affects the scalp-to-cortex distance (SCD) and the comprising tissues. This is crucial for noninvasive neuroimaging and brain stimulation modalities as they rely on traversing from the scalp to the cortex or vice versa. The specific relationship between aging and these tissues has not been comprehensively investigated. We conducted a study on 250 younger and older adults to examine age-related differences in SCD and its constituent tissues. We identified region-specific differences in tissue thicknesses related to age and sex. Older adults exhibit larger SCD in the frontocentral regions compared to younger adults. Men exhibit greater SCD in the inferior scalp regions, while women show similar-to-greater SCD values in regions closer to the vertex compared to men. Younger adults and men have thicker soft tissue layers, whereas women and older adults exhibit thicker compact bone layers. CSF is considerably thicker in older adults, particularly in men. These findings emphasize the need to consider age, sex, and regional differences when interpreting SCD and its implications for noninvasive neuroimaging and brain stimulation.

Graph theory-based EEG source connectivity for assessing biomechanical performance in transfemoral amputees with vibrotactile feedback.

Recent research has shown that the complex and dynamic behaviour of isolated regions is necessary for the proper functioning of the human brain. To this end, network neuroscience evaluates the neural channels that respond to diverse motor tasks and assesses the brain’s functionality. However, the utilization of network neuroscience has not been done to map out the cortical sources in lower limb amputee’s postural control. Our earlier research shows that transfemoral amputees’ fronto-central region and secondary somatosensory cortex have substantial functional connections while they are balancing with vibrotactile feedback. In this work, we advanced to investigate the cortical sources of transfemoral amputee’s postural stability improvement with vibrotactile feedback. The results highlight the predominance of cortical sources in frontal and parietal lobe in alpha frequency band. The observation shows the connectivity of left superiorparietal, lateralorbitofrontal and right rostranteriorcingulate, supramarginal, and inferiorparietal sources. Moreover, the node strength of these cortical sources significantly changes (p<0.05, ANOVA) with the effect of feedback and visual input. In future, it could be interesting to develop some neural feedback techniques intended to improve the postural performance of lower limb amputees by making these cortical sources more adaptable via local stimulation techniques.

Juvenile idiopathic epilepsy in Egyptian Arabian foals, a potential animal model of self-limited epilepsy in children.

Juvenile idiopathic epilepsy (JIE) is categorized as a generalized epilepsy. Epilepsy classification entails electrocortical characterization and localization of epileptic discharges (ED) using electroencephalography (EEG). Characterize epilepsy in Egyptian Arabian foals with JIE using EEG. Sixty-nine foals (JIE, 48; controls, 21). Retrospective study. Inclusion criteria consisted of Egyptian Arabian foals: (1) JIE group diagnosed based on witnessed or recorded seizures, and neurological and EEG findings, and (2) control group of healthy nonepileptic age-matched foals. Clinical data were obtained in 48 foals. Electroencephalography with photic stimulation was performed under standing sedation in 37 JIE foals and 21 controls. Abnormalities on EEG were found in 95% of epileptic foals (35 of 37) and in 3 of 21 control asymptomatic foals with affected siblings. Focal ED were detected predominantly in the central vertex with diffusion into the centroparietal or frontocentral regions (n = 35). Generalization of ED occurred in 14 JIE foals. Epileptic discharges commonly were seen during wakefulness (n = 27/37 JIE foals) and sedated sleep (n = 35/37 JIE foals; 3/21 controls). Photic stimulation triggered focal central ED in 15 of 21 JIE foals. Juvenile idiopathic epilepsy has a focal onset of ED at the central vertex with spread resulting in clinical generalized tonic-clonic seizures with facial motor activity and loss of consciousness. Electroencephalography with photic stimulation contributes to accurate phenotyping of epilepsy. Foals with this benign self-limiting disorder might serve as a naturally occurring animal model for self-limited epilepsy in children.

Electrophysiological correlates of objective memory impairments in community‐dwelling older adults at risk of dementia

AbstractBackgroundThe electrophysiological correlates of Short‐Term Memory Binding (STMB) have been previously investigated in older adults at risk of dementia (i.e., Mild Cognitive Impairment ‐MCI). Pietto et al. (2016) reported reduced early electrophysiological activity (100‐250 ms) over fronto‐central (FC) and parieto‐occipital (PO) regions in MCI patients recruited from clinic. We investigated if such an electrophysiological pattern is also observed in a larger sample of community‐dwelling older adults with MCI who had not sought medical advice.MethodsA sample of 215 community‐dwelling older adults were recruited into the study. They were assessed with a battery of cognitive tests including CERAD (Aguirre‐Acevedo et al., 2016), the Addenbrooke’s Cognitive Examination (ACE‐R), the STMB Task, clinical, and functional scales. The STMB task assesses the ability to detect changes between two consecutive visual arrays of coloured shapes. Changes consisted of shapes swapping colours (the binding condition). Time‐locked EEG signals were collected while participants performed the STMB task. Monte Carlo tests and non‐parametric bootstrapping running 1000 permutations revealed electrodes and time windows of relevance.ResultsA group of 108 participants met classical criteria for MCI (Petersen, 2004; Winblad et al., 2004). They showed impaired STMB abilities. ERP analyses revealed significant Group x Time Windows interactions (p&lt;0.01). Early ERP showed reduced neural recruitment (MCI&lt;HC) on the left PO and right centro‐parietal (CP) (300‐500ms) regions during shape‐colour encoding, and on PO bilaterally and left FC during retrieval (150‐450ms). Late ERP showed increased neural recruitment (MCI&gt;HC) on right fronto‐central (FC) regions (900‐1200ms) during shape‐colour encoding, and on left FC and PO regions (872‐1200ms) during retrieval.ConclusionAltered spatio‐temporal dynamics underpinning STMB deficits in MCI patients followed a pattern similar to that described by Pietto et al. (2016). Of note, we observed hyper‐recruitment for late ERP linked to encoding and retrieval over anterior and posterior regions of the STMB network. Such hyper‐recruitment may reflect compensatory changes in the early stages of MCI. These results confirm the usefulness of EEG‐based cognitive biomarkers to screen community‐dwelling older adults at risk of dementia.Aguirre‐Acevedo et al. (2016). Int. Psychogeriatr, 28(3), 503‐510.Pietto et al. (2016). Journal of Alzheimer’s Disease, 53(4), 1325‐1340.

The characteristics of audiovisual temporal integration in streaming-bouncing bistable motion perception: considering both implicit and explicit processing perspectives.

This study explored the behavioral and neural activity characteristics of audiovisual temporal integration in motion perception from both implicit and explicit perspectives. The streaming-bouncing bistable paradigm (SB task) was employed to investigate implicit temporal integration, while the corresponding simultaneity judgment task (SJ task) was used to examine explicit temporal integration. The behavioral results revealed a negative correlation between implicit and explicit temporal processing. In the ERP results of both tasks, three neural phases (PD100, ND180, and PD290) in the fronto-central region were identified as reflecting integration effects and the auditory-evoked multisensory N1 component may serve as a primary component responsible for cross-modal temporal processing. However, there were significant differences between the VA ERPs in the SB and SJ tasks and the influence of speed on implicit and explicit integration effects also varied. The aforementioned results, building upon the validation of previous temporal renormalization theory, suggest that implicit and explicit temporal integration operate under distinct processing modes within a shared neural network. This underscores the brain's flexibility and adaptability in cross-modal temporal processing.

Psychophysiology of Monotonous Driving, Fatigue and Sleepiness in Train and Non-Professional Drivers: Driver Safety Implications.

Fatigue and sleepiness are complex bodily states associated with monotony as well as physical and cognitive impairment, accidents, injury, and illness. Moreover, these states are often characteristic of professional driving. However, most existing work has focused on motor vehicle drivers, and research examining train drivers remains limited. As such, the present study psychophysiologically examined monotonous driving, fatigue, and sleepiness in a group of passenger train drivers and a group of non-professional drivers. Sixty-three train drivers and thirty non-professional drivers participated in the present study, which captured 32-lead electroencephalogram (EEG) data during a monotonous driving task. Fatigue and sleepiness were self-evaluated using the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Karolinksa Sleepiness Scale, and the Checklist of Individual Strength. Unexpectedly, fatigue and sleepiness scores did not significantly differ between the groups; however, train drivers generally scored lower than non-professional drivers, which may be indicative of individual and/or industry attempts to reduce fatigue. Across both groups, fatigue and sleepiness scores were negatively correlated with theta, alpha, and beta EEG variables clustered towards the fronto-central and temporal regions. Broadly, these associations may reflect a monotony-associated blunting of neural activity that is associated with a self-reported fatigue state.

Features of epileptic encephalopathy caused by SCN1A mutation

Background. The development and availability of genetic research open both new possibilities in the diagnosis of epileptic encephalopathies and require the search for correlations between detected pathological mutation and the clinical and instrumental examination of a child. In particular, seizure disorders in children in whom SCN1A has been detected cover a spectrum that varies from simple febrile seizures and mild generalized epilepsy with febrile seizures plus, which was first described in 2003, to severe myoclonic epilepsy in infancy (more commonly known as Dravet syndrome) or severe intractable childhood epilepsy with generalized tonic-clonic seizures. Materials and methods. In our study, we examined 4 children (2 boys and 2 girls) with clinical and instrumental signs of epileptic encephalopathy with resistant seizures who were treated in the psychoneurology department for children with perinatal pathology and orphan diseases of the SI “Lukyanova Institute of Pediatrics, Obstetrics and Gynecology named of the National Academy of Medical Sciences of Ukraine”. The average age of patients was 2.20 ± 1.55 years. In addition to the laboratory and instrumental examination, all children underwent a medical genetic analysis (whole exome sequencing or next-generation sequencing) and the mutation of the SCN1A gene was detected. Subsequently, the relationship between the obtained laboratory instrumental and clinical anamnestic data was analyzed using statistical research methods. Results. It should be noted that the onset of genetic disorders caused by SCN1A occurs at the age of 5.5–6 months. During the onset, focal clonic seizures predominate, mainly against the background of hyperthermia, which are later modified into generalized tonic-clonic, myoclonic ones, and even absences. In three of four cases, the epileptiform activity was focal, with a predominant localization in the fronto-central regions followed by generalization. In all children, taking into account the focal onset of attacks, therapy was started with the use of carbamazepine, which is contraindicated in children with this mutation. After analyzing our cases, we saw that the course of the disease and the resistance of attacks were more severe in girls. The study of this phenomenon requires observation of a larger number of children. Conclusions. In children with genetically determined epileptic encephalopathy caused by the SCN1A mutation, the onset of the disease occurs in the first half of life and is usually manifested itself by focal seizures. In children with SCN1A mutation, frontal localization of epileptiform activity prevails. Considering this feature of the disease and based on our own long-term observation of children with epileptic encephalopathies of early age, we would like to warn against the use of carbamazepines in this age group. The course of SCN1A epileptic encephalopathy (Dravet syndrome) is difficult, given the resistance of attacks and regression in the development of a child, and often requires the use of more than 2–3 antiepileptic drugs, but a correctly selected combination allows long-term remission to be achieved.

Top-down reconfiguration of SMA cortical connectivity during action preparation

The Bereitschaftspotential (BP), a scalp potential recorded in humans during action preparation, is characterized by a slow amplitude increase over fronto-central regions as action execution approaches. We recorded TMS evoked-potentials (TEP) stimulating the supplementary motor area (SMA) at different time-points during a Go/No-Go task to assess whether and how cortical excitability and connectivity of this region change as the BP increases. When approaching BP peak, left SMA reactivity resulted greater. Concurrently, its effective connectivity increased with the left occipital areas, while it decreased with the right inferior frontal gyrus, indicating a fast reconfiguration of cortical networks during thepreparation of the forthcoming action. Functional connectivity patterns supported these findings, suggesting a critical role of frequency-specific inter-areal interactions in implementing top-down mechanisms in the sensorimotor system prior to action. These findings reveal that BP time-course reflects quantitative and qualitative changes in SMA communication patterns that shape mechanisms involved in motor readiness.

Impact of varying levels of mental stress on phase information of EEG Signals: A study on the Frontal, Central, and parietal regions

Mental stress is a commonly occurring phenomenon that impacts people from diverse backgrounds and is associated with numerous physical and psychological illnesses. The brain plays a vital role in how individuals perceive and react to stress, including their physiological and behavioral responses. In this study, our objective was to investigate the impact of varying levels of induced stress, ranging from mild to severe, on brain activity. Our primary interest was to determine if mental stress would influence neural coordination, as assessed through intertrial phase clustering (ITPC). Furthermore, we hypothesized that an increase in perceived mental stress would result in reduced regional connectivity as measured via phase-lag index (PLI). EEG data from 41 participants (20 females, 21 males, age range 18 to 46; mean = 26.1; SD = 7.06) were collected while they were exposed to three levels of mental stress, using a parametric modulation study design. Following pre-processing, we extracted the two mentioned features and performed statistical analysis. As an additional analysis, we assessed the discriminatory power of these features using a Random Forest classifier. Statistical analysis revealed a significant decrease of ITPCs over frontal, central, and parietal regions accompanying increased levels of stress. The results obtained from the PLI analysis showed that the increase in levels of stress were associated with a decrease in the brain connectivity over the frontocentral, frontoparietal, and centroparietal regions. The classification result showed that the Random Forrest classifier predict three levels of stress with 83.78% accuracy. These findings indicate that phase-based EEG features could serve as a novel neurometric for quantifying in vivo stress levels. Furthermore, this study could contribute to developing more precise tools to measure mental stress objectively.