Midfrontal Regions Research Articles

Electrophysiological activity is associated with vulnerability of Internet addiction in non-clinical population

This study investigated the electrophysiological activity associated with vulnerability of problematic Internet use in non-clinical population. The resting EEG spectrum of alpha (8–13 Hz) rhythm was measured in 22 healthy subjects who have used the Internet for recreational purpose. The vulnerability of Internet addiction was assessed using Young's Internet Addiction Test (IAT) and Assessment for Computer and Internet Addiction-Screener (AICA-S) respectively. Depression and impulsivity were also measured with Beck Depression Inventory (BDI) and Barratt Impulsiveness Scale 11(BIS-11) respectively. The IAT was positively correlated with alpha power obtained during eyes closed (EC, r = 0.50, p = 0.02) but not during eyes open (EO). This was further supported by a negative correlation (r = −0.48, p = 0.02) between IAT scores and alpha desynchronization (EO-EC). These relationships remained significant following correction for multiple comparisons. Furthermore, The BDI score showed positive correlation with alpha asymmetry at mid-lateral (r = 0.54, p = 0.01) and mid-frontal (r = 0.46, p = 0.03) regions during EC, and at mid-frontal (r = 0.53, p = 0.01) region during EO. The current findings suggest that there are associations between neural activity and the vulnerability of problematic Internet use. Understanding of the neurobiological mechanisms underlying problematic Internet use would contribute to improved early intervention and treatment.

Wronger than wrong: Graded mapping of the errors of an avatar in the performance monitoring system of the onlooker

EEG studies show that observing errors in one's own or others' actions triggers specific electro-cortical signatures in the onlooker's brain, but whether the brain error-monitoring system operates according to graded or discrete rules is still largely unknown. To explore this issue, we combined immersive virtual reality with EEG recording in participants who observed an avatar reaching-to-grasp a glass from a first-person perspective. The avatar could perform correct or erroneous actions. Erroneous grasps were defined as small or large depending on the magnitude of the trajectory deviation from the to-be-grasped glass. Results show that electro-cortical indices of error detection (indexed by ERN and mid-frontal theta oscillations), but not those of error awareness (indexed by error-Positivity), were gradually modulated by the magnitude of the observed errors. Moreover, the phase connectivity analysis revealed that enhancement of mid-frontal theta phase synchronization paralleled the magnitude of the observed error. Thus, theta oscillations represent an electro-cortical index of the degree of control exerted by mid-frontal regions whose activation depends on how much an observed action outcome results maladaptive for the onlooker. Our study provides novel neurophysiological evidence that the error monitoring system maps observed errors of different magnitude according to fine-grain, graded rather than all-or-none rules.

Frontal infraslow activity marks the motor spasms of anti-LGI1 encephalitis

ObjectiveThe clinical and electrographic features of seizures in anti-LGI1 encephalitis are distinct from those seen in other autoimmune encephalitides or non-encephalitic epilepsies. One electroclinical phenomenon specific to the condition consists of lateralized motor spasms, known as faciobrachial dystonic seizures (FBDS). An electrodecremental pattern overriding a “DC shift” has been described as the EEG correlate of these spasms. We sought to further characterize this pre-spasm infraslow activity (ISA). MethodsContinuous video-EEG recordings were acquired in four patients with anti-LGI1 encephalitis: each had frequent motor spasms/FBDS as well as frequent subclinical temporal lobe seizures (an independent indicator of anti-LGI1 encephalitis). ResultsIn artifact-free recordings obtained using clinical amplifiers equipped with a low frequency analog filter of 0.07 Hz, ISA reliably preceded clinical onset of the motor spasms by ∼1.2 s and preceded the electrodecremental pattern by ∼700 ms. Pre-spasm ISA was invariably recorded contralateral to FBDS, with a voltage topographic maximum over the mid frontal region. The pre-movement ISA differed from the Bereitschaftspotential in timing and topography and was an order of magnitude higher in amplitude. Sporadic FBDS that occurred in association with temporal lobe seizures were preceded by identical ISA. ConclusionsThe motor spasms of anti-LGI1 encephalitis are preceded by frontal ISA. A paucity of data at the microscale level precludes mechanistic explanations at the macroscale level, or even determination of the relative contributions of neurons and glia in the generation of the ISA. SignificanceAlthough fundamental cellular mechanisms await elucidation, the pre-spasm ISA represents a singular and readily identifiable EEG response to this autoimmune brain disorder.

Intracranial source activity (eLORETA) related to scalp-level asymmetry scores and depression status.

Frontal EEG alpha asymmetry provides a promising index of depression risk, yet very little is known about the neural sources of alpha asymmetry. To identify these sources, this study examined alpha asymmetry using a distributed inverse solution: exact low resolution brain electromagnetic tomography (eLORETA). Findings implicated a generator in lateral midfrontal regions that contributed to both surface asymmetry and depression risk. Participants with any lifetime history of depressive episodes were characterized by less left than right activity in the precentral gyrus and midfrontal gyrus. Anhedonia accounted for a significant portion of the relationship between alpha asymmetry and lifetime major depressive disorder. Results are suggestive of convergence between motivational and capability models of asymmetry and replicate results from experimental studies in a large resting-state data set. The capability model of frontal alpha asymmetry is contextualized in terms of motor preparedness following emotional mobilization.

Analysis of functional brain connections for positive-negative emotions using phase locking value.

In this study, we investigate the brain networks during positive and negative emotions for different types of stimulus (audio only, video only and audio+video) in [Formula: see text], and [Formula: see text] bands in terms of phase locking value, a nonlinear method to study functional connectivity. Results show notable hemispheric lateralization as phase synchronization values between channels are significant and high in right hemisphere for all emotions. Left frontal electrodes are also found to have control over emotion in terms of functional connectivity. Besides significant inter-hemisphere phase locking values are observed between left and right frontal regions, specifically between left anterior frontal and right mid-frontal, inferior-frontal and anterior frontal regions; and also between left and right mid frontal regions. ANOVA analysis for stimulus types show that stimulus types are not separable for emotions having high valence. PLV values are significantly different only for negative emotions or neutral emotions between audio only/video only and audio only/audio+video stimuli. Finding no significant difference between video only and audio+video stimuli is interesting and might be interpreted as that video content is the most effective part of a stimulus.

The picture morphing task – an efficient and quick means to measure updating

We report the results of three studies using a picture morphing task. We argue that this task is an effective, easy to administer, and widely applicable assessment tool for probing the ability to update perceptual representations. By presenting a series of fifteen images that morph from one unambiguous object (e.g., rabbit) to a completely different object (e.g., duck), we can assess the time and evidence necessary for perceptual re-categorization in children, brain-damaged adults, and normal adult controls. Study one presented 3 and 5 year old children with a version of the picture morphing task and a Theory of Mind assessment (i.e., False Belief Task). The picture morphing task could be performed by both age groups. Within the 5-year old group, children who passed a False Belief Task and were able to correctly explain why, showed faster perceptual updating. Study two demonstrated that damage to the right hemisphere – especially the right anterior insula – resulted in an updating impairment; these patients requiring significantly more pictures before they reported the new object compared to left brain damaged patients. In study three, an fMRI experiment with healthy individuals, the anterior insula and mid-frontal regions were activated at the time when a change was reported, and immediately before. In summary, the picture morphing task offers an an efficient tool for measuring updating mental representations in vastly different experimental settings and participant populations. Meeting abstract presented at VSS 2016

Modulation of EEG Theta Band Signal Complexity by Music Therapy

The primary goal of this study was to investigate the impact of monochord (MC) sounds, a type of archaic sounds used in music therapy, on the neural complexity of EEG signals obtained from patients undergoing chemotherapy. The secondary goal was to compare the EEG signal complexity values for monochords with those for progressive muscle relaxation (PMR), an alternative therapy for relaxation. Forty cancer patients were randomly allocated to one of the two relaxation groups, MC and PMR, over a period of six months; continuous EEG signals were recorded during the first and last sessions. EEG signals were analyzed by applying signal mode complexity, a measure of complexity of neuronal oscillations. Across sessions, both groups showed a modulation of complexity of beta-2 band (20–29[Formula: see text]Hz) at midfrontal regions, but only MC group showed a modulation of complexity of theta band (3.5–7.5[Formula: see text]Hz) at posterior regions. Therefore, the neuronal complexity patterns showed different changes in EEG frequency band specific complexity resulting in two different types of interventions. Moreover, the different neural responses to listening to monochords and PMR were observed after regular relaxation interventions over a short time span.

The Egg-Burster in the Asian PlanthopperRicania speculum(Walker) (Hemiptera Ricaniidae)

The exotic planthopper, Ricania speculum (Walker), was detected in 2014 in Liguria, Northern Italy, and recorded as first alert for Europe. This highly polyphagous species lays eggs on a wide range of host plants, including economically important crops. In this paper, we provide details on the egg-burster morphology and on the role it plays in the hatching process. Eggs are laid inside the tissues of young twigs or in the leaf midrib, leaving the anterior half and the micropylar area partially exposed. At hatching time, the mature embryo pierces through the eggshell with an egg-burster located on the mid-frontal region of the embryonic cuticle, never described so far in this species and in other Ricaniids. During the process of hatching, the embryonic cuticle splits over the head, progressively slipping downwards, and is finally released over the empty eggshell, with the egg-burster.

A cortical network that marks the moment when conscious representations are updated

In order to survive in a complex, noisy and constantly changing environment we need to categorize the world (e.g., Is this food edible or poisonous?) and we need to update our interpretations when things change. How does our brain update when object categories change from one to the next? We investigated the neural correlates associated with this updating process. We used event-related fMRI while people viewed a sequence of images that morphed from one object (e.g., a plane) to another (e.g., a shark). All participants were naïve as to the identity of the second object. The point at which participants ‘saw' the second object was unpredictable and uncontaminated by any dramatic or salient change to the images themselves. The moment when subjective perceptual representations changed activated a circumscribed network including the anterior insula, medial and inferior frontal regions and inferior parietal cortex. In a setting where neither the timing nor nature of the visual transition was predictable, this restricted cortical network signals the time of updating a perceptual representation. The anterior insula and mid-frontal regions (including the ACC) were activated not only at the actual time when change was reported, but also immediately before, suggesting that these areas are also involved in processing alternative options after a mismatch has been detected.

Introduction of Sharp Objects in to Brain With Infanticidal Intention.

Dear Editor Child abuse, malicious and deliberate intention of harming or killing a child, is well-documented in history and is more hideous in infants due to their disability to communicate and defend, making them more susceptible victims for such a crime. Embedding sewing needle(s) into brain through natural openings and soft parts of the cranium has been reported for infanticide purpose (1). The relative small number of reported cases in medical literature does not match the real number of cases due to missed-detections, lack of physician referral or infant death before disclosure of respective cause (1, 2). A 57-year-old man presented with symptoms of an ischemic cerebrovascular accident (CVA). Brain CT scan revealed a left middle cerebral artery territory infarct and surprisingly a metallic foreign body embedded in mid-frontal region slightly deviated to the right (Figure 1 A) that proved to be artifacts of a sewing needle on plain X-rays (Figure 1 B). The site of entry seemed to be anterior fontanel showed as a dimple on 3D CT reconstruction of the skull (Figure 1 C). Figure 1. A, Brain CT scan on admission confirms infarction in left middle cerebral artery territory and presence of a metallic foreign body in mid-frontal region with slight right deviation. B, Three dimensional skull CT scan showing a sharp thin object in frontal ... There was no record or sign of previous trauma or any surgical procedures on the scalp, skull or brain. The family denied any unusual childhood or infancy background including non-parental babysitter or stepmother. Past medical history lacked of any relevant symptoms attributable to the presence of foreign body in the brain. Finally, we came to conclusion that this was an accidental finding. Convenient brain penetration sites for sharp small-caliber objects are non-ossified regions including fontanels, cranial sutures, ear canal and orbits during infancy (4, 5), with anterior fontanel as the most primeval and particular site due to its width and noticeability. Therefore, it was commonly used by non-medical offenders. Proper healing and concealing make the introduction site unnoticed and if the patient survives from the acute and subacute complications, metallic object would sink deeper into brain; probably as its higher specific gravity and also impact of cerebral pulsations (6). Metallic foreign bodies, especially iron-made needles, are usually well-tolerated in brain, as lack of air exposure and irregular iron phosphate spots on the needle play protective roles against the corrosive process (4). Thus, its size and shape will retain for decades. The usual approaches to such patients have ranged from follow-up observations to surgical interventions with a variety of outcomes (1, 5). Unless a definite relationship between patient’s clinical manifestations and presence of sharp object is established, intention of a surgical intervention should be either avoided or carefully weighed against the possible complications of such an approach.

White matter pathology and disconnection in the frontal lobe in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

BackgroundMagnetic resonance imaging indicates diffuse white matter (WM) changes are associated with cognitive impairment in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We examined whether the distribution of axonal abnormalities is related to microvascular pathology in the underlying WM.MethodsWe used post-mortem brains from CADASIL subjects and similar age cognitively normal controls to examine WM axonal changes, microvascular pathology, and glial reaction in up to 16 different regions extending rostro-caudally through the cerebrum. Using unbiased stereological methods, we estimated length densities of affected axons immunostained with neurofilament antibody SMI32. Standard immunohistochemistry was used to assess amyloid precursor protein immunoreactivity per WM area. To relate WM changes to microvascular pathology, we also determined the sclerotic index (SI) in WM arterioles.ResultsThe degree of WM pathology consistently scored higher across all brain regions in CADASIL subjects (P < 0.01) with the WM underlying the primary motor cortex exhibiting the most severe change. SMI32 immunoreactive axons in CADASIL were invariably increased compared with controls (P < 0.01), with most prominent axonal abnormalities observed in the frontal WM (P < 0.05). The SIs of arterioles in CADASIL were increased by 25–45% throughout the regions assessed, with the highest change in the mid-frontal region (P = 0.000).ConclusionsOur results suggest disruption of either cortico-cortical or subcortical-cortical networks in the WM of the frontal lobe that may explain motor deficits and executive dysfunction in CADASIL. Widespread WM axonal changes arise from differential stenosis and sclerosis of arterioles in the WM of CADASIL subjects, possibly affecting some axons of projection neurones connecting to targets in the subcortical structures.

Stimulus-response mappings shape inhibition processes: a combined EEG-fMRI study of contextual stopping.

Humans are rarely faced with one simple task, but are typically confronted with complex stimulus constellations and varying stimulus-relevance in a given situation. Through modifying the prototypical stop-signal task and by combined recording and analysis of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), we studied the effects of stimulus relevance for the generation of a response or its inhibition. Stimulus response mappings were modified by contextual cues, indicating which of two different stimuli following a go stimulus was relevant for stopping. Overall, response inhibition, that is comparing successful stopping to a stop-signal against go-signal related processes, was associated with increased activity in right inferior and left midfrontal regions, as well as increased EEG delta and theta power; however, stimulus-response conditions in which the most infrequent stop-signal was relevant for inhibition, were associated with decreased activity in regions typically involved in response inhibition, as well as decreased activity in the delta and theta bands as compared to conditions wherein the relevant stop-signal frequency was higher. Behaviorally, this (aforementioned) condition, which demanded inhibition only from the most infrequent stimulus, was also associated with reduced reaction times and lower error rates. This pattern of results does not align with typical stimulus frequency-driven findings and suggests interplay between task relevance and stimulus frequency of the stop-signal. Moreover, with a multimodal EEG-fMRI analysis, we demonstrated significant parameterization for response inhibition with delta, theta and beta time-frequency values, which may be interpreted as reflecting conflict monitoring, evaluative and/or motor processes as suggested by previous work (Huster et al., 2013; Aron, 2011). Further multimodal results suggest a possible neurophysiological and behavioral benefit under conditions whereby the most infrequent stimulus demanded inhibition, indicating that the frequency of the stop-signal interacts with the current stimulus-response contingency. These results demonstrate that response inhibition is prone to influence from other cognitive functions, making it difficult to dissociate real inhibitory capabilities from the influence of moderating mechanisms.

Effects of Visual Working Memory on Brain Information Processing of Irrelevant Auditory Stimuli

Selective attention has traditionally been viewed as a sensory processing modulator that promotes cognitive processing efficiency by favoring relevant stimuli while inhibiting irrelevant stimuli. However, the cross-modal processing of irrelevant information during working memory (WM) has been rarely investigated. In this study, the modulation of irrelevant auditory information by the brain during a visual WM task was investigated. The N100 auditory evoked potential (N100-AEP) following an auditory click was used to evaluate the selective attention to auditory stimulus during WM processing and at rest. N100-AEP amplitudes were found to be significantly affected in the left-prefrontal, mid-prefrontal, right-prefrontal, left-frontal, and mid-frontal regions while performing a high WM load task. In contrast, no significant differences were found between N100-AEP amplitudes in WM states and rest states under a low WM load task in all recorded brain regions. Furthermore, no differences were found between the time latencies of N100-AEP troughs in WM states and rest states while performing either the high or low WM load task. These findings suggested that the prefrontal cortex (PFC) may integrate information from different sensory channels to protect perceptual integrity during cognitive processing.

Sexual dimorphism in ALS: Exploring gender-specific neuroimaging signatures

Our objective was to explore neuroanatomical differences between female and male ALS patients in the context of sexual dimorphism in healthy controls. Fourteen female ALS patients, 13 male ALS patients, 22 healthy male controls and 20 healthy female controls were recruited into a comprehensive neuroimaging study. Cortical thickness measurements and diffusion tensor imaging (DTI) were utilized to explore gender-specific anatomical vulnerability. DTI analysis across all study groups revealed higher fractional anisotropy in association with male gender in the brainstem, cerebellum, fornix, thalamus, anterior forceps and corticospinal tracts accounting for diagnosis and age. While females showed a trend of higher age-adjusted cortical thickness in the right parieto-occipital and left mid-frontal regions, males demonstrated higher cortical thickness in the left lingual and left superior temporal regions, accounting for diagnosis. Significant multifocal white matter differences have also been identified between healthy male and female controls. In conclusion, sexual dimorphism is an overlooked and potentially confounding factor in admixed ALS neuroimaging studies. Our results suggest that gender is an additional dimension of disease heterogeneity in ALS. Given the significant pre- and post-morbid gender differences, we feel that ALS imaging studies should be controlled for gender or, alternatively, single gender studies should be considered.

The catechol-O-methyltransferase Val158Met polymorphism modulates fronto-cortical dopamine turnover in early Parkinson’s disease: a PET study

Cognitive deficits occur in up to 30% of patients with early Parkinson's disease, some of which are thought to result from dysfunction within the fronto-striatal dopaminergic network. Recently, it has been shown that a common functional polymorphism (Val(158)Met) in the catechol-O-methyltransferase (COMT) gene is associated with changes in executive performance in tasks that have a fronto-striatal basis. This is thought to relate to changes in cortical dopamine levels as catechol-O-methyltransferase is the main mode of inactivation for dopamine in frontal areas. However to date, no study has investigated dopamine turnover as a function of this genetic polymorphism in Parkinson's disease. We, therefore, set out to investigate in vivo changes in presynaptic dopamine storage in patients with idiopathic Parkinson's disease as a function of the catechol-O-methyltransferase Val(158)Met polymorphism using (18)F-DOPA positron emission tomography. Twenty patients with Parkinson's disease (10 homozygous for Val/Val and 10 for Met/Met catechol-O-methyltransferase polymorphisms) underwent (18)F-DOPA positron emission tomography using a prolonged imaging protocol. The first dynamic scan was acquired from 0 to 90 min (early), and the second scan (late) from 150 to 210 min post-intravenous radioligand administration. Patients were matched for age, sex, verbal IQ, disease duration and severity of motor features. (18)F-DOPA influx constants (Ki) were calculated and compared for frontal and striatal regions. Late scan mean frontal and striatal Ki values were significantly reduced in both Parkinson's disease groups relative to early scan Ki values. Met/Met patients had significantly higher late scan Ki values compared with their Val/Val counterparts in anterior cingulate, superior frontal and mid-frontal regions but early frontal Ki values were not different between the two groups. As late Ki values reflect rates of dopamine metabolism to 3,4-dihydroxyphenylacetic acid and homovanillic acid, our results indicate that Met homozygotes have higher presynaptic dopamine levels in frontal regions than Val homozygotes, which may help to explain how this genotypic variation may influence the fronto-striatal cognitive deficits of Parkinson's disease.

Characteristics of Cortical Activation in Schizophrenia during the Card Game ^|^ldquo;Concentration^|^rdquo;

Various functional imaging studies have demonstrated reduced lateralization of cortical activation during neurocognitive tasks in schizophrenia. -A well-known card game, "concentration", reflects working memory (WM). We compared characteristics of hemodynamic changes in the prefrontal to temporo-parietal areas of the brain during this card game between 24 outpatients with schizophrenia and 24 age- and gender-matched healthy control subjects. Using multi-channel near-infrared spectroscopy, we measured relative changes in oxygenated hemoglobin concentration (oxy-Hb changes), which reflects brain activity during this task. Patients showed reduced lateralization in the midfrontal area, which is involved in executive functions, and in the inferior parietal area, involved in WM subcomponents. We also found a significant negative correlation between left midfrontal region oxy-Hb changes and severity of negative symptoms of schizophrenia. Our results characterized disease-related features, suggesting the usefulness of oxy-Hb change measurement during this card game for assessing functional outcome in schizophrenic patients.

Arterial spin labeling and altered cerebral blood flow patterns in the minimally conscious state

To use arterial spin labeling (ASL) to compare cerebral blood flow (CBF) patterns in minimally conscious state (MCS) patients with those in normal controls in an observational study design. Subjects meeting MCS criteria and normal controls were identified. A pseudocontinuous ASL sequence was performed with subjects and controls in the resting awake state. Multiple CBF values for 10 predetermined regions of interest were sampled and average CBF was calculated and compared between controls and subjects. Ten normal controls were identified, with ages ranging from 26 to 54 years. Four subjects met the MCS criteria and received an ASL study, with one patient receiving a second study at a later date. Subjects ranged in age from 19 to 58 years and had traumatic brain injury, stroke, or hypoxic-ischemic encephalopathy. Regional CBF for controls ranged from 21.6 to 57.2 mL/100 g/min, with a pattern of relatively increased blood flow posteriorly including the posterior cingulate, parietal, and occipital cortices. CBF patterns for MCS subjects showed greater variability (from 7.7 to 33.1 mL/100 g/min), demonstrating globally decreased CBF in gray matter compared with that in normal controls, especially in the medial prefrontal and midfrontal regions. In the one subject studied longitudinally, global CBF values increased over time, which correlated with clinical improvement. We identified globally decreased CBF and a selective reduction of CBF within the medial prefrontal and midfrontal cortical regions as well as gray matter in MCS patients. ASL may serve as an adjunctive method to assess functional reserve in patients recovering from severe brain injuries.

Adults with Attention-Deficit/Hyperactivity Disorder ? A Brain Magnetic Resonance Spectroscopy Study

Background: Impaired cognitive control in individuals with attention-deficit/hyperactivity disorder (ADHD) may be related to a prefrontal cortical glutamatergic deficit. We assessed the glutamate level in the left and the right midfrontal region including the anterior cingulate cortex in adults with ADHD and healthy controls. Methods: Twenty-nine adults with ADHD and 38 healthy controls were included. We used Proton Magnetic Resonance Imaging with single voxel point-resolved spectroscopy to measure the ratio of glutamate to creatine (Glu/Cre) in the left and the right midfrontal region in the two groups. Results: The ADHD group showed a significant reduction of Glu/Cre in the left midfrontal region compared to the controls. Conclusion: The reduction of Glu/Cre in the left midfrontal region in the ADHD group may reflect a glutamatergic deficit in prefrontal neuronal circuitry in adults with ADHD, resulting in problems with cognitive control.

Bilateral brain regions associated with naming in older adults

To determine structural brain correlates of naming abilities in older adults, we tested 24 individuals aged 56–79 on two confrontation-naming tests (the Boston Naming Test (BNT) and the Action Naming Test (ANT)), then collected from these individuals structural Magnetic-Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI) data. Overall, several regions showed that greater gray and white matter volume/integrity measures were associated with better task performance. Left peri-Sylvian language regions and their right-hemisphere counterparts, plus left mid-frontal gyrus correlated with accuracy and/or negatively with response time (RT) on the naming tests. Fractional anisotropy maps derived from DTI showed robust positive correlations with ANT accuracy bilaterally in the temporal lobe and in right middle frontal lobe, as well as negative correlations with BNT RT, bilaterally, in the white matter within middle and inferior temporal lobes. We conclude that those older adults with relatively better naming skills can rely on right-hemisphere peri-Sylvian and mid-frontal regions and pathways, in conjunction with left-hemisphere peri-Sylvian and mid-frontal regions, to achieve their success.

Melanotic neuroectodermal tumor of the brain recurring 12 years after complete remission: case report

We describe a rare case of melanotic neuroectodermal tumor (MNT) of the brain recurring 12 years after complete remission. An 11-year-old girl initially presented with exotropia and bilateral papilledema. Magnetic resonance (MR) imaging revealed an intracranial extraaxial large tumor at the midfrontal region. T(1)-weighted MR imaging showed the tumor to be well delineated with homogeneous enhancement by gadolinium. The tumor was subtotally removed, and the histological diagnosis was MNT. The residual tumor became enlarged, so gamma knife radiosurgery was performed 5 months after initial surgery. The enhanced lesion disappeared, but another lesion emerged 3 years later. A second gamma knife radiosurgery was performed for this local recurrence. The enhanced lesion disappeared once again. Twelve years after the second gamma knife radiosurgery, another local recurrence was detected. This tumor was subtotally removed. Histological examination confirmed the same diagnosis of MNT. This case suggests that MNTs not completely resected need long-term follow up, even if complete remission was achieved after adjuvant therapy.