Central Frontal Regions Research Articles

Double-triangular flap for reconstruction of a circular skin defect in the central frontal region

Double-triangular flap for reconstruction of a circular skin defect in the central frontal region

Electroencephalogram Alpha Oscillations in Stroke Recovery: Insights into Neural Mechanisms from Combined Transcranial Direct Current Stimulation and Mirror Therapy in Relation to Activities of Daily Life.

The goal of stroke rehabilitation is to establish a robust protocol for patients to live independently in community. Firstly, we examined the impact of 3 hybridized transcranial direct current stimulation (tDCS)-mirror therapy interventions on activities of daily life (ADL) in stroke patients. Secondly, we explored the underlying therapeutic mechanisms with theory-driven electroencephalography (EEG) indexes in the alpha band. This was achieved by identifying the unique contributions of alpha power in motor production to ADL in relation to the premotor cortex (PMC), primary cortex (M1), and Sham tDCS with mirror therapy. The results showed that, although post-intervention ADL improvement was comparable among the three tDCS groups, one of the EEG indexes differentiated the interventions. Neural-behavioral correlation analyses revealed that different types of ADL improvements consistently corresponded with alpha power in the temporal lobe exclusively in the PMC tDCS group (all rs > 0.39). By contrast, alterations in alpha power in the central-frontal region were found to vary, with ADL primarily in the M1 tDCS group (r = -0.6 or 0.7), with the benefit depending on the complexity of the ADL. In conclusion, this research suggested two potential therapeutic mechanisms and demonstrated the additive benefits of introducing theory-driven neural indexes in explaining ADL.

A predictive model combining connectomics and entropy biomarkers to discriminate long-term vagus nerve stimulation efficacy for pediatric patients with drug-resistant epilepsy.

To predict the vagus nerve stimulation (VNS) efficacy for pediatric drug-resistant epilepsy (DRE) patients, we aim to identify preimplantation biomarkers through clinical features and electroencephalogram (EEG) signals and thus establish a predictive model from a multi-modal feature set with high prediction accuracy. Sixty-five pediatric DRE patients implanted with VNS were included and followed up. We explored the topological network and entropy features of preimplantation EEG signals to identify the biomarkers for VNS efficacy. A Support Vector Machine (SVM) integrated these biomarkers to distinguish the efficacy groups. The proportion of VNS responders was 58.5% (38/65) at the last follow-up. In the analysis of parieto-occipital α band activity, higher synchronization level and nodal efficiency were found in responders. The central-frontal θ band activity showed significantly lower entropy in responders. The prediction model reached an accuracy of 81.5%, a precision of 80.1%, and an AUC (area under the receiver operating characteristic curve) of 0.838. Our results revealed that, compared to nonresponders, VNS responders had a more efficient α band brain network, especially in the parieto-occipital region, and less spectral complexity of θ brain activities in the central-frontal region. We established a predictive model integrating both preimplantation clinical and EEG features and exhibited great potential for discriminating the VNS responders. This study contributed to the understanding of the VNS mechanism and improved the performance of the current predictive model.

RADT-03. IDENTIFYING BRAIN STRUCTURES LINKED TO RADIATION-INDUCED ENDOCRINE AND COGNITIVE SEQUELAE: A MULTI-CENTRE VOXEL-BASED ANALYSIS

Abstract BACKGROUND Radiotherapy (RT) is a common treatment for paediatric brain tumours. Despite advancements in techniques to mitigate RT-induced toxicity, almost two-thirds of patients develop long-lasting endocrine and cognitive sequalae. Image-based data mining (IBDM) is a voxel-based analysis tool that can identify dose-sensitive regions, supporting development of tailored radiation treatments for future patients that avoids these regions. We present the first IBDM study localising endocrine and cognitive effects in paediatric brain tumour patients. METHODS Imaging (MRI and CT) and clinical data were available for 261 children (146 medulloblastoma patients in centre A, 115 patients with mixed diagnoses in centre B). Outcomes were reported as Growth Hormone Deficiency (GHD, presence/absence, both centres) and processing speed (PS, continuous slope derived from a linear mixed-effects model, centre A). IBDM evaluated where dose was associated with outcome (p-value<0.01). Mean dose to this region was included in multivariable analysis adjusting for age, risk status, hydrocephalus status/management, and chemotherapy. RESULTS GHD was associated with dose to a region overlapping the pituitary and brainstem. In centre A, multivariable analysis revealed a 13(2-27)% average increase in GHD odds per 1Gy increase in dose, with an inverse effect for age. Center B showed a 8(4-13)% average increase for every 1Gy, with no other predictors. For PS, a central frontal region from the medial frontal lobes to the hypothalamus was identified (139 patients in centre A). Every 1Gy increase led to a -0.08(-0.20 – 0.04) PS change, with age and hydrocephalus management as contributing factors. CONCLUSION We identified a region (encompassing the pituitary and brainstem) associated with increased risk of GHD, that was consistent in two independent cohort analyses. Furthermore, PS decline was linked to dose to a frontal region. Minimising dose to these regions for future patients could reduce the risk of cognitive and endocrine sequelae.

Unconsciously triggered cognitive conflict influences perceptual choice in active and sedentary individuals.

People who regularly exercise and receive training perform better when actioning unconscious cognitive tasks. The information flow triggered by a single unconscious visual stimulus has been extensively investigated, but it remains unclear whether multiple unconscious visual stimuli interact. This study aimed to explore the relationship between three simultaneous subliminal arrow stimuli (pointing in same or different directions), focusing on how they interact with each other and the subsequent priming effect on the target arrow in active and sedentary groups. We used a priming paradigm combining flanker task to test the hypothesis. A total of 42 participants were recruited. Of these, 22 constituted the active group and 20 constituted the sedentary group. Behavioral data results revealed that the main effects of group and prime-target compatibility were significant. In the neurophysiological data, prime-target compatibility significantly influenced the latency of PP1. The amplitude of TP1 and TN2 mainly influenced the prime-flanker congruency. The prime-flanker congruency and groups interacted when the prime-target showed sufficient compatibility. The prime-flanker congruency, and the prime-target compatibility considerably influenced the TP3 amplitude in the anterior central frontal region (CZ electrode point). Event-related potentials revealed the interactions between conscious processing and subliminal conflict in the early stages of perceptual and attention processing (target-related P1 potential component). These results suggest that exercise is helpful for coping with unconscious cognitive conflict.

Lagrangian three-dimensional transport and dispersion by submesoscale currents at an upper-ocean front

The three-dimensional transport pathways, the time and space scales of vertical transport, and the dispersion characteristics (single-, pair- and multi-particle statistics) of submesoscale currents at an upper-ocean front are investigated using material points (tracer particles) that advect with the local fluid velocity. Coherent vortex filaments and eddies, generated and sustained during the evolution of baroclinic instability, dominate submesoscale (0.1 - 10 km) dynamics. These coherent structures play a crucial role in the particle transport and dispersion, which we quantify here. Particles in the central frontal region organize into vertically inclined lobes with anticyclonic circulation, each associated with a coherent eddy with cyclonic rotation. Furthermore, the coherent filaments associated with heavy/light edges of the front transfer particles from the edges to the lobes by downwelling/upwelling. This flux of new particles into the central region causes the particles circulating in the lobes to adjust, which leads to slumping of the front. The particle motion in the vertical shows multiple time scales – a fast time scale with O(10m) vertical displacement within an hour and a slower near-inertial time scale, comparable to the intrinsic time scale of the growing instability. The fast O(1h) time scale is also seen in the decorrelation of vertical velocity and the tapering of the initial ballistic growth of relative particle dispersion. The overall slumping process is slower than what one might anticipate from the large magnitude of vertical velocity in the filaments since it requires a sustained correlation over time between the lateral and the vertical motion. By tracking clouds of particles, we show that their centers of mass downwell/upwell over 1−2 inertial time periods, after which an adjustment follows with a sub-inertial time scale. The shape change in clusters of four particles reveals filamentogenesis, i.e. deformation into thin, needle-like structures by the coherent, anisotropic motions of the submesoscale, which occurs as a rapid process that is complete within approximately an hour.

Does the Instruction “Be Original and Create” Actually Affect the EEG Correlates of Performing Creative Tasks?

The study provides the data related to synchronization/desynchronization when performing verbal creative (to create the endings of proverbs) and noncreative (to find a synonym for the ending of the known proverb; to remember the known ending of the proverb) tasks, as well as the data on classification of EEG patterns during these tasks. Twenty-four volunteers (18–22 y.o., 20 women, 4 men) participated in the study. Creation of original endings vs. memory task was accompanied by the higher values of EEG power in the frontal region of the right hemisphere in the frequency range 8–9 Hz for the time interval of 400–730 ms. In the parietal region of the left hemisphere in the same frequency range, the higher EEG spectral power EEG values were obtained while creating both original and synonymous endings compared to the “recall/memory” control task. When creating original and synonymous endings, the power of EEG was higher in the central frontal regions for the 14–15 Hz frequency band, as well as in the right hemisphere F4 and P4 used for the tasks with synonyms compared to the memory task (850–950 ms). For the frequencies of 17–21 Hz, there were no differences between the creative and synonymous tasks; at the same time, the creative task as compared to the task for memory was characterized by differences in the parietal sites bilaterally and in the central frontal region only for the frequencies of 17–18 Hz, while the synonyms task as compared to the memory one differed in the specified regions for the frequency range of 17–21 Hz. The EEG signal classification was carried out using the classifier learning software package in the matlab environment. The results of classification were considered on the basis of linear discriminant analysis, the support vector machine, and the method that gave the best classification result. An EEG signal converted to current source density (CSD) from frontal (F3, Fz, F4) and parietal regions (P3, Pz, P4) located on the surface of the skull according to the 10–20 System was used for classification. The average accuracy of single trial classification for three types of tasks in all subjects was 48.7 ± 5% [SD] for the best classifier; the best result of the individual subject (58.5%) was achieved using linear discriminant analysis at the theoretical threshold of random classification of 33%.

Mirror Visual Feedback Combining Vibrotactile Stimulation Promotes Embodiment Perception: An Electroencephalogram (EEG) Pilot Study.

As one determinant of the efficacy of mirror visual feedback (MVF) in neurorehabilitation, the embodiment perception needs to be sustainable and enhanced. This study explored integrating vibrotactile stimulation into MVF to promote the embodiment perception and provide evidence of the potential mechanism of MVF. In the experiment, the participants were instructed to keep their dominant hand still (static side), while open and close their non-dominant hand (active side) and concentrate on the image of the hand movement in the mirror. They were asked to tap the pedal with the foot of the active side once the embodiment perception is generated. A vibrotactile stimulator was attached on the hand of the active side, and three conditions were investigated: no vibration (NV), continuous vibration (CV), and intermittent vibration (IV). The effects were analyzed on both objective data, including latency time (LT) and electroencephalogram (EEG) signals, and subjective data, including embodiment questionnaire (EQ). Results of LT and EQ suggested a stronger subjective sense of embodiment under the condition of CV and IV, comparing with NV. No significant difference was found between CV and IV. EEG analysis showed that in the hemisphere of the static side, the desynchronization of CV and IV around the central-frontal region (C3 and F3) in the alpha band (8–13 Hz) was significantly prominent compared to NV, and in the hemisphere of the active side, the desynchronization of three conditions was similar. The network analysis of EEG data indicated that there was no significant difference in the efficiency of neural communication under the three conditions. These results demonstrated that MVF combined with vibrotactile stimulation could strengthen the embodiment perception with increases in motor cortical activation, which indicated an evidence-based protocol of MVF to facilitate the recovery of patients with stroke.

Physical Activity and Neural Correlates of Sad Facial Expressions in Premenstrual Syndrome

Exercise benefits our emotional function, particularly frontal lobe-mediated cognitive processes. Recent studies have indicated that affective neural circuits are modulated by premenstrual syndrome (PMS). Meanwhile, observational studies have reported that physical activity can promote PMS remission. Nonetheless, few studies have investigated the effect of physical activity on sad emotion recognition from a neurobiological perspective. Our objective was to explore the relationships between exercise and high order sad emotion cognitive processing in women with PMS. We conducted a sad facial emotion recognition task to examine the effects of aerobic exercise on activity in central frontal regions with electroencephalography in 31 participants. Participants were divided into a high (HPMS) or low severity PMS (LPMS) group according to self-reported PMS scores. We then analyzed cortical activity in response to sad cues, comparing such activity between the groups. Repeated ANOVA and pooled t statistics were used for statistical analysis. We observed a significant reduction in the N250 wave evoked by sad emotions after exercise compared with baseline at most channels in HPMS (P < 0.05), but not in LPMS. There was also a significant post-exercise prolongation of N250 latency at F3 and C3 in HPMS. There were no differences in N250 activation between the groups at baseline but significantly lower activation was noted in the lateral prefrontal cortex (PFC: F7 and F8) of HPMS compared with LPMS after exercise. Furthermore, higher PMS scores were significantly associated with greater PFC-N250 amplitude before exercise, but this was not observed after exercise. Acute exercise induced significant brain activity changes in response to sad cues in the HPMS group only. Furthermore, significantly lower activation of the lateral PFC was found after exercise in HPMS compared with LPMS. Given our results, we discuss the potential efficacy of exercise to modulate emotional context or sad emotion regulatory capabilities in women with PMS.

Frontal and glabellar myotomy: single short frontal scar approach

BACKGROUND: Frontal and glabellar muscle hyperactivity with consequent wrinkles are frequent complaints in plastic surgery. Treatment consists of impediment of related muscles; this can be achieved by application of botulinum toxin or surgery by means of classic coronal incision, endoscopic approach, transblepharoplasty access, or non-endoscopic limited approaches. This paper proposes an alternative of limited approach in which an incision is made on the central frontal scalp for treatment of the frontal and glabellar muscles. METHODS: Between March 2009 and April 2010, 20 female patients were treated using a small incision on the frontal scalp, followed by dissection of frontal and glabellar regions. Muscles and supratrochlear and supraorbital nerve branches were identified; subsequently, frontal and glabellar muscle myotomy was performed. RESULTS: All patients showed good results by frontal and glabellar muscle impediment during the evaluation period, with improvement in wrinkles and hyperactivity. Complications consisted of temporary paresthesia and pruritus in the central frontal region and scalp, in addition to recurrence of partial muscle contraction. CONCLUSIONS: The small incision approach on the central frontal scalp for treatment of frontal and glabellar muscles seems to be a good alternative to other surgical options due to its small size, inconspicuous scarring, and direct visualization of frontal and glabellar anatomic structures, allowing selective myotomy or myectomy

A clinical and magnetoencephalography study of MRI-negative startle epilepsy

Objective The goal of this study was to investigate clinical findings, ictal semiology, and results of video/electroencephalography (video/EEG), and magnetoencephalography (MEG) in patients with startle epilepsy and normal brain MRI. Methods Four patients (mean age 12.5 years) with startle epilepsy were investigated with MRI, video/EEG, and MEG. Results Epilepsy diagnosis was established in childhood, and all had spontaneous and reflex seizures. Reflex seizures were triggered by sudden, unexpected sounds and tactile stimuli. The neurological examinations and MRIs were normal. MEG recordings showed focal epileptiform activity. An ictal MEG was obtained in one patient. Source modeling yielded dipole sources in right central frontal region. Conclusion The present study demonstrates that the origin of epileptiform activity in startle epilepsy can be localized in brain areas associated with supplementary motor seizures, even in patients with normal brain MRI. MEG adds complementary information to the localization of epileptiform activity and can be useful in planning invasive studies in cases evaluated for epilepsy surgery.

Phytoplankton size classes competitions at sub-mesoscale in a frontal oceanic region

The effects of mesoscale and sub-mesoscale dynamics on the competition between two different phytoplankton size classes are investigated with a 3D primitive equations model. The model reproduces realistic simulations of mesoscale turbulence generated by a westward current in the southern hemisphere at statistical equilibrium in a summer situation. Effects of two different grazing pressures on phytoplankton competitions are compared and the role of eddy variability is quantified comparing high and low resolution simulations. High resolution simulations reveal a filamentary distribution of biomass and nutrients induced by the combination of vertical advection and horizontal stirring. This fine scale variability is observed not only on the horizontal but also on the vertical into the subsurface chlorophyll maximum. One of the key results is that such a dynamics induces a spatial segregation of the phytoplankton in the southern part of the frontal region that is mainly filamentary. This spatial segregation consists in biomass maxima for large phytoplankton in rich nutrients filaments and maxima for small phytoplankton outside these filaments. This anti-correlation is particularly strong when grazing pressure is low and is confirmed by statistical analysis. In the central frontal region, dominated by mesoscale dynamics, the two phytoplankton classes are strongly correlated together and biomass maxima are located close to downwelling regions that are poor in nutrients. It is shown that the effect of grazing is significantly amplified by the fine scale dynamics and that the combination of these two mechanisms is responsible of a switch of the ecosystem dominance in the surface layers. In addition, the effect of frontal dynamics on the detritus export is very sensitive to grazing pressure: increasing grazing induces a significant decrease of the export in the presence of frontal dynamics whereas it induces an increase of the export without small-scale variability.

Long-term abstinence syndrome in heroin addicts: indices of P300 alterations associated with a short memory task

Attentional deficits have been implicated in the pathophysiology of opioid addicts. The P300 component of event-related potentials (ERPs) is considered as a manifestation of attentional operations. The authors' goal was the comparison of P300 elicited during a short memory test between subjects with prolonged heroin abstinence and current heroin users as well as healthy controls. The P300 component was evaluated during the anticipatory period of a short memory task in 20 patients characterized by a past history of opioid dependence (6 months abstinence), in 18 current heroin users and in 20 healthy comparison subjects, matched for age, sex and educational level. Abstinent heroin addicts exhibited significant reduction of P300 amplitude at central frontal region, relative to the other two groups. The findings are discussed in connection to the aim of identifying psychophysiological indices, addressing issues in opioid use disorders, and suggest that knowledge about cognitive operations, such as those reflected by P300 component, could provide further insight into psychophysiological mechanisms underlying the long-term abstinence state of heroin addicts.

Psychophysiological correlates in male to female transsexuals studied with a P300 investigation

Transsexualism is thought to be related to cortical processes reflecting a complex mosaic of biological, psychological and social/cultural information. Since the P300 component of event-related potentials is considered as an index of attentional processes, the present study focuses on auditory P300 elicited during a short memory test in male to female (MF) transsexuals, compared with that in healthy controls. The P300 component was evaluated during the anticipatory period of a short memory test in 13 MF transsexuals who had a gender reassignment operation, at least 3 years previously (mean time 17-6 years, range 3-31 years) and 26 healthy subjects (11 males and 15 females) matched for age and educational level. MF transsexuals exhibited significant reduction of P300 amplitude in the left frontal and temporoparietal areas in comparison to the control group. Furthermore, the group of transsexuals showed a significant delay of P300 latency in comparison to the controls, at the central frontal region. These findings point to significant psychophysiological alterations of distributed cortical circuits in MF transsexuals. These alterations may be critically related to the biological substrate of MF transsexualism.