Frontal Cortex Research Articles

Anatomy and Microsurgical Relevance of the Outer Arachnoid Envelope around the Olfactory Bulb Based on Endoscopic Cadaveric Observations.

There is high risk of injury to the olfactory tract and olfactory bulb during surgery of the anterior cranial fossa. The goal of this study was to describe the outer arachnoid envelope around the olfactory bulb, which plays a significant role in approach-related injury of the nerve. A total of 20 fresh human cadaveric heads were examined. Five cadaveric heads were used to describe a gross overview of the topographic anatomy of the outer arachnoid cover of the olfactory bulb. In 15 cadaveric heads, endoscopic surgical approaches were performed to examine the in situ undisrupted anatomy of the outer arachnoid around the olfactory bulb. Four cadaveric heads were used for the lateral subfrontal approach, 5 heads for the medial subfrontal approach, 3 heads for the median subfrontal approach, and 3 heads for the anterior interhemispheric approach. The outer arachnoid membrane of the frontal lobe attaches the olfactory bulb strongly to the above lying olfactory sulcus. Only the most rostral portion of the olfactory bulb became slightly detached from the frontal lobe. The outer arachnoid forms a decent protrusion around the tip of the olfactory bulbs. The fila olfactoria have their own outer arachnoid cover as a continuation of the same layer of the olfactory bulb. The effect of brain retraction and manipulation forces on the olfactory bulb and the role of the arachnoid membranes located here were visually analyzed and described in detail through the four different neurosurgical approaches we performed. The results of our observations provide important anatomical details for preserving the sense of smell during neurosurgical procedures.

White matter and cortical gray matter microstructural abnormalities in new daily persistent headache: a NODDI study.

New daily persistent headache (NDPH) is a rare primary headache with unclear pathogenesis. Neuroimaging studies of NDPH are limited, and controversy still exists. Diffusion tensor imaging (DTI) is commonly used to study the white matter. However, lacking specificity, the potential pathological mechanisms of white matter microstructural changes remain poorly understood. In addition, the intricacy of gray matter structures impedes the application of the DTI model. Here, we applied an advanced diffusion model of neurite orientation dispersion and density imaging (NODDI) to study the white matter and cortical gray matter microstructure in patients with NDPH. This study assessed brain microstructure, including 27 patients with NDPH, and matched 28 healthy controls (HCs) by NODDI. The differences between the two groups were assessed by tract-based spatial statistics (TBSS) and surface-based analysis (SBA), focusing on the NODDI metrics (neurite density index (NDI), orientation dispersion index (ODI), and isotropic volume fraction (ISOVF)). Furthermore, we performed Pearson's correlation analysis between the NODDI indicators and clinical characteristics. Compared to HCs, patients with NDPH had a reduction of density and complexity in several fiber tracts. For robust results, the fiber tracts were defined as comprising more than 100 voxels, including bilateral inferior fronto-occipital fasciculus (IFOF), left superior longitudinal fasciculus (SLF) and inferior longitudinal fasciculus (ILF), as well as right corticospinal tract (CST). Moreover, the reduction of neurite density was uncovered in the left superior and middle frontal cortex, left precentral cortex, and right lateral orbitofrontal cortex and insula. There was no correlation between the NODDI metrics of these brain regions and clinical variables or scales of relevance after the Bonferroni correction. Our research indicated that neurite loss was detected in both white matter and cortical gray matter of patients with NDPH.

Targeting the Manifestations of Subclinical and Overt Hypothyroidism Within the Hippocampus.

The past decade has witnessed a surge of articles describing the neurocognitive sequelae and associated structural and functional brain abnormalities of patients with overt (OH) and subclinical hypothyroidism (SCH). Findings show effects primarily within the frontal lobes with usually worse outcomes for OH than SCH. Several recent studies have also indicated hypothyroid patients may have smaller hippocampi, a key structure for memory. The current JCEM paper by T. Zhang and colleagues applies two novel approaches for analyzing hippocampal structure and function. One uses an automated processing tool that segments the hippocampus into distinct subregions and the other, performs connectivity analysis to assess the relationships between specific hippocampal subregions and cortical areas. Relatively large samples of OH and SCH patients and healthy controls received a test of global cognitive functioning and structural and functional MRIs. Results showed hypothyroid groups scored significantly below controls on the memory scale and also had smaller hippocampal volumes in selective subregions. Effects were stronger for SCH than OH groups, who also showed different patterns of interconnectivity between hippocampal subregions and specific frontal-lobe areas. To make sense of these findings, I explored the rodent and human literatures on thyroid hormone's role in hippocampal functioning and on hippocampal subfields and their purported functions and interconnections. Because current results suggest SCH may represent a distinct clinical entity with unique brain manifestations, I hypothesized two explanations for these findings, one involving transporter defects in the brain barriers and the other, differential neurodegeneration of the blood-brain-barrier vascular unit.

The influence of multiple cognitive workload levels of an exergame on dorsal attention network connectivity at the source level

This study investigates how adding a cognitive task on a balance board (exergame) affects connectivity in the dorsal attention network (DAN) during an exergame task. Healthy young adults performed a soccer ball-moving task by tilting a balance board with their feet while their brain activity was measured using electroencephalography (EEG). In this exergame, the speed of obstacles in front of the goal manipulated the cognitive workload. Higher speed means a higher cognitive workload. The study found significant changes in functional connectivity within DAN regions, specifically in the alpha band. During the shift from easy to medium cognitive task, we observed a significant increase in connectivity (p= 0.0436) between the right inferior temporal (ITG R) and the Left middle temporal (MTG L). During the transition from easy to hard cognitive tasks, strengthened interactions (p= 0.0324) between inferior temporal (ITG) and parsopercularis (pOPPER) were found. This suggests that the proposed balanceboard-based exergame enhances the functionality of specific brain regions, such as ITG and MTG regions, and improves connectivity in the frontal cortex. We also found a correlation between brain activity and performance data, highlighting that increased cognitive workload resulted in decreased performance and heightened frontal alpha activity. These findings align with research suggesting that adding cognitive games to physical activity-based tasks in rehabilitation programs can boost brain activity, resulting in improved decision-making and visual processing skills. This information can help clinicians tailor rehabilitation methods that target specific brain regions.

Thalamocortical functional connectivity and rapid antidepressant and antisuicidal effects of low-dose ketamine infusion among patients with treatment-resistant depression.

Previous studies have shown an association between the thalamocortical dysconnectivity and treatment-resistant depression (TRD). Whether a single subanesthetic dose of ketamine may change thalamocortical connectivity among patients with TRD is unclear. Whether these changes in thalamocortical connectivity is associated with the antidepressant and antisuicidal effects of ketamine treatment is also unclear. Two resting-state functional MRIs were collected in two clinical trials of 48 patients with TRD (clinical trial 1; 32 receiving ketamine, 16 receiving a normal saline placebo) and 48 patients with TRD and strong suicidal ideation (clinical trial 2; 24 receiving ketamine, 24 receiving midazolam), respectively. All participants underwent rs-fMRI before and 3 days after infusion. Seed-based functional connectivity (FC) was analyzed in the left/right thalamus. FCs between the bilateral thalamus and right middle frontal cortex (BA46) and between the left thalamus and left anterior paracingulate gyrus (BA8) increased among patients in the ketamine group in clinical trials 1 and 2, respectively. FCs between the right thalamus and bilateral frontal pole (BA9) and between the right thalamus and left rostral paracingulate gyrus (BA10) decreased among patients in the ketamine group in clinical trials 1 and 2, respectively. However, the associations between those FC changes and clinical symptom changes did not survive statistical significance after multiple comparison corrections. Whether ketamine-related changes in thalamocortical connectivity may be associated with ketamine's antidepressant and antisuicidal effects would need further investigation. Clinical trials registration: UMIN Clinical Trials Registry (UMIN-CTR): Registration number: UMIN000016985 and UMIN000033916.

Minimally Invasive Bilateral Duo-Keyhole Approach for Giant Falcine Meningioma: 2 Dimensional Operative Video.

One of the key concepts behind minimally invasive keyhole cranial surgery is that as the operative corridor deepens, it also widens. The corridor should therefore be designed parallel to the long-axis of the tumor to optimize visualization.1 These ideas were applied in a duo-keyhole operation for a falcine meningioma. The patient is a 79-year-old woman diagnosed with a large falcine meningioma compressing both frontal lobes. Her tumor was oriented with the long-axis, perpendicular to the superior sagittal sinus, and has bulbous extensions on both sides of the falx. Incisions on the falx, anterior and posterior to the tumor, in addition to a cut between it and the undersurface of the superior sagittal sinus, would render it practically devascularized and "free-floating.2" One keyhole was insufficient, but one anterior and another posterior to the tumor would make the falcine cuts feasible. The operation was performed with the above scheme and the posterior keyhole to the left and anterior one to the right of midline to facilitate surface vascular detachment on both sides. The patient recovered well and was discharged home after 4 days. This procedure highlights that flexible application of the principles of minimally invasive keyhole. Neurosurgery can tailor-make an operation to precisely fit the unique features of a patient and the tumor. The procedure was performed under the ethical guidelines of our hospital. No Institutional Review Board consent was required or sought because the patient gave specific consent to the procedure and publication of her image.

A perspective on epigenomic aging processes in the human brain and their plasticity in patients with mental disorders - a systematic review.

The debate surrounding nature versus nurture remains a central question in neuroscience, psychology, and in psychiatry, holding implications for both aging processes and the etiology of mental illness. Epigenetics can serve as a bridge between genetic predisposition and environmental influences, thus offering a potential avenue for addressing these questions. Epigenetic clocks, in particular, offer a theoretical framework for measuring biological age based on DNA methylation signatures, enabling the identification of disparities between biological and chronological age. This structured review seeks to consolidate current knowledge regarding the relationship between mental disorders and epigenetic age within the brain. Through a comprehensive literature search encompassing databases such as EBSCO, PubMed, and ClinicalTrials.gov, relevant studies were identified and analyzed. Studies that met inclusion criteria were scrutinized, focusing on those with large sample sizes, analyses of both brain tissue and blood samples, investigation of frontal cortex markers, and a specific emphasis on schizophrenia and depressive disorders. Our review revealed a paucity of significant findings, yet notable insights emerged from studies meeting specific criteria. Studies characterized by extensive sample sizes, analysis of brain tissue and blood samples, assessment of frontal cortex markers, and a focus on schizophrenia and depressive disorders yielded particularly noteworthy results. Despite the limited number of significant findings, these studies shed light on the complex interplay between epigenetic aging and mental illness. While the current body of literature on epigenetic aging in mental disorders presents limited significant findings, it underscores the importance of further research in this area. Future studies should prioritize large sample sizes, comprehensive analyses of brain tissue and blood samples, exploration of specific brain regions such as the frontal cortex, and a focus on key mental disorders. Such endeavors will contribute to a deeper understanding of the relationship between epigenetic aging and mental illness, potentially informing novel diagnostic and therapeutic approaches.

Descriptions of new and rare crabs associated with coral rubble and sponges from Kanyakumari, southeastern Arabian Sea, southern India (Decapoda: Brachyura: Epialtidae and Pilumnidae)

Three new brachyuran crab species are described from coral rubble and sponges collected in the southern Indian state of Tamil Nadu. The epialtid, Acanthophrys keeae n. sp., was obtained from coral rubble and is the first species from the genus reported from the Indian Ocean. It is most similar to A. costatus Griffin & Tranter 1986, from eastern Australia, but can be distinguished by the proportionately longer postorbital spine, more strongly granulated gastric region, relatively less inflated and narrower branchial region, sinuous outer margin of the basal antennal article which has the median part concave, almost smooth merus of the cheliped, more elongate male anterior thoracic sternum, more triangular male pleon, and the distal two-thirds of the male first gonopod being almost straight. The pilumnid, Latopilumnus ajmali n. sp., was found in the sponge, Callyspongia (Cladochalina) diffusa (Ridley, 1884), and is characterised by its carapace and pereiopods being covered by a relatively dense coat of short setae with only scattered simple long setae, and the dorsal carapace surface being almost smooth with the regions poorly demarcated. Vellumnus intonsus n. sp. (Pilumnidae) was present in coral rubble, is morphologically most similar to V. penicillatus (Gordon, 1930) (Hong Kong) and V. pygmaeus Takeda, 1977 (Japan) but can be separated by the lateral lobule of the front being separated from the frontal lobes by a deep cleft, the more prominently convex supraorbital margin, triangular external orbital tooth, presence of larger granules on the cheliped carpus and chela, and the distal part of the male first gonopod is proportionately stouter and distinctly hooked.

From long-term to short-term: Distinct neural networks underlying semantic knowledge and its recruitment in working memory

Although numerous studies suggest that working memory (WM) and semantic long-term knowledge interact, the nature and underlying neural mechanisms of this intervention remain poorly understood. Using functional magnetic resonance imaging (fMRI), this study investigated the extent to which neural markers of semantic knowledge in long-term memory (LTM) are activated during the WM maintenance stage in 32 young adults. First, the multivariate neural patterns associated with four semantic categories were determined via an implicit semantic activation task. Next, the participants maintained words – the names of the four semantic categories implicitly activated in the first task – in a verbal WM task. Multi-voxel pattern analyses showed reliable neural decoding of the four semantic categories in the implicit semantic activation and the verbal WM tasks. Critically, however, no between-task classification of semantic categories was observed. Searchlight analyses showed that for the WM task, semantic category information could be decoded in anterior temporal areas associated with abstract semantic category knowledge. In the implicit semantic activation task, semantic category information was decoded in superior temporal, occipital and frontal cortices associated with domain-specific semantic feature representations. These results indicate that item-level semantic activation during verbal WM involves shallow rather than deep semantic information.

From long-term to short-term: Distinct neural networks underlying semantic knowledge and its recruitment in working memory

Although numerous studies suggest that working memory (WM) and semantic long-term knowledge interact, the nature and underlying neural mechanisms of this intervention remain poorly understood. Using functional magnetic resonance imaging (fMRI), this study investigated the extent to which neural markers of semantic knowledge in long-term memory (LTM) are activated during the WM maintenance stage in 32 young adults. First, the multivariate neural patterns associated with four semantic categories were determined via an implicit semantic activation task. Next, the participants maintained words – the names of the four semantic categories implicitly activated in the first task – in a verbal WM task. Multi-voxel pattern analyses showed reliable neural decoding of the four semantic categories in the implicit semantic activation and the verbal WM tasks. Critically, however, no between-task classification of semantic categories was observed. Searchlight analyses showed that for the WM task, semantic category information could be decoded in anterior temporal areas associated with abstract semantic category knowledge. In the implicit semantic activation task, semantic category information was decoded in superior temporal, occipital and frontal cortices associated with domain-specific semantic feature representations. These results indicate that item-level semantic activation during verbal WM involves shallow rather than deep semantic information.

Aerobic Exercise Improves Cognitive Flexibility and Modulates Regional Volume Changes in a Rat Model of Autism

Gestational exposure to valproic acid (VPA) is a risk factor for autism spectrum disorder (ASD). Rodents exposed to VPA in utero display common features of ASD, including volumetric dysregulation in higher-order cognitive regions like the medial prefrontal cortex (mPFC), the anterior cingulate cortex (ACC), and the hippocampus. Exercise has been shown in elderly populations to boost cognition and to buffer against brain volume losses with age. This study employed an adolescent treadmill exercise intervention to facilitate cognitive flexibility and regional brain volume regulation in rats exposed to VPA during gestation. It was found that exercise improved performance on extra-dimensional shifts of attention on a set-shifting task, which is indicative of improved cognitive flexibility. Exercise decreased frontal cortex volume in females, whereas in males exercise increased the ventral hippocampus. These findings suggest that aerobic exercise may be an effective intervention to counteract the altered development of prefrontal and hippocampal regions often observed in ASD.

Structure focused neurodegeneration convolutional neural network for modelling and classification of Alzheimer’s disease

Alzheimer’s disease (AD), the predominant form of dementia, is a growing global challenge, emphasizing the urgent need for accurate and early diagnosis. Current clinical diagnoses rely on radiologist expert interpretation, which is prone to human error. Deep learning has thus far shown promise for early AD diagnosis. However, existing methods often overlook focal structural atrophy critical for enhanced understanding of the cerebral cortex neurodegeneration. This paper proposes a deep learning framework that includes a novel structure-focused neurodegeneration CNN architecture named SNeurodCNN and an image brightness enhancement preprocessor using gamma correction. The SNeurodCNN architecture takes as input the focal structural atrophy features resulting from segmentation of brain structures captured through magnetic resonance imaging (MRI). As a result, the architecture considers only necessary CNN components, which comprises of two downsampling convolutional blocks and two fully connected layers, for achieving the desired classification task, and utilises regularisation techniques to regularise learnable parameters. Leveraging mid-sagittal and para-sagittal brain image viewpoints from the Alzheimer’s disease neuroimaging initiative (ADNI) dataset, our framework demonstrated exceptional performance. The para-sagittal viewpoint achieved 97.8% accuracy, 97.0% specificity, and 98.5% sensitivity, while the mid-sagittal viewpoint offered deeper insights with 98.1% accuracy, 97.2% specificity, and 99.0% sensitivity. Model analysis revealed the ability of SNeurodCNN to capture the structural dynamics of mild cognitive impairment (MCI) and AD in the frontal lobe, occipital lobe, cerebellum, temporal, and parietal lobe, suggesting its potential as a brain structural change digi-biomarker for early AD diagnosis. This work can be reproduced using code we made available on GitHub.

A Comparative Study on Cognitive Assessment in Cerebellar and Supratentorial Stroke

This study aims to understand the cognitive profiles of cerebellar infarction patients and compare them to those with supratentorial infarctions, particularly frontal infarctions. This current study also aims to find reliable assessment tools for detecting cognitive impairment in cerebellar infarction patients. A total of fifty cerebellar infarction patients, sixty supratentorial infarction patients, and thirty-nine healthy controls were recruited. The Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Addenbrooke’s Cognitive Examination III (ACE-III), and Cerebellar Cognitive Affective Syndrome scale (CCAS-s) were used to assess global cognitive function. An extensive neuropsychological assessment battery was also tested to evaluate the characteristics of each cognitive domain. To assess the features of cognitive function, a comprehensive neuropsychological evaluation tool was also utilized. The cerebral infarction patients demonstrated cognitive impairment comparable to those with frontal infarcts, notably characterized by disturbance in attention and executive function. However, the degree of cognitive impairment was comparatively milder in cerebellar infarction patients. Furthermore, the patients in the cerebellar group had worse scores in the ACE-III and CCAS-s compared to healthy controls. The two assessments also demonstrated a significant area under the curve values, indicating their effectiveness in distinguishing cognitive impairment in cerebellar infarctions. In conclusion, cognitive impairment in a cerebellar infarction resembles frontal lobe dysfunction but is generally mild. It can be accurately assessed using the ACE-III and CCAS-s scales.

Case Report: Persistent residual shunt after a first percutaneous PFO closure followed by minimally invasive surgical failure: third time is a charm

BackgroundEven though the optimal management of a moderate or large residual shunt following patent foramen ovale (PFO) closure is open to question, recent data confirmed that it is associated with an increased risk of stroke recurrence.Case summaryA 48-year-old woman, a migraineur with visual aura, was diagnosed with a PFO associated with a huge multifenestrated atrial septal aneurysm (mfASA) and a moderate right-to-left shunt, detectable only after a Valsalva maneuver on contrast-transthoracic echocardiography. Brain magnetic resonance imaging showed a 1-mm silent white matter lesion in the right frontal lobe. Although the indication was not supported by guidelines, a transcatheter PFO closure was performed at another center with implantation of a large, equally sized, double-disc device (Figulla UNI 33/33 mm). At 6-month follow-up, a 2D/3D transesophageal echocardiography (TEE) color Doppler showed incorrect orientation of the device, which was not parallel to the interatrial septum, with two discs failing to capture the aortic muscular rim and partially protruding in the right atrium; furthermore, a 4 mm × 7 mm ASA fenestration was documented with a residual bidirectional shunt. Thereafter, the same team performed a minimally invasive cardiac surgery under femoro-femoral cardiopulmonary bypass; however, the procedure proved ineffective and was complicated by postoperative pericarditis with pericardial effusion, requiring further rehospitalization 1 month later due to persistent pericarditis, bilateral pleuritis, phrenic nerve palsy, and atrial flutter, which was treated with amiodarone. The patient asked for a second opinion, and our multidisciplinary heart team decided to offer a percutaneous redo intervention. An uneventful implantation of a regular PFO occluder (Figulla Flex II 16/18 mm) across the septal defect was performed successfully. Twelve-month follow-up with 2D TTE color Doppler and contrast transcranial Doppler showed correct position and good interaction between the two devices, with no residual shunt.DiscussionIn addition to the incorrect indication for PFO closure and the failure of minimally invasive surgery, the procedural mishap in this case could have been due to the inappropriate implantation of the first large device within the tunnel. It would have been better to deploy the same large device in the most central fenestration, covering the PFO and a greater part of the remaining mfASA at the same time.

Case report: Assessing criminal responsibility and recidivism risk in the behavioral variant of frontotemporal dementia

Frontotemporal dementia (FTD) affects the frontal and temporal lobes of the brain, leading to personality changes, language impairments, and behavioral disturbances, including impulsivity and disinhibition. Assessing responsibility and recidivism risk in forensic evaluations is challenging due to the evolving nature of FTD. Despite limited literature, we present a case of a 45-year-old man with no prior legal or medical history, who committed criminal acts due to behavioral changes linked to the behavioral variant of frontotemporal dementia (bvFTD). Initial assessment found him irresponsible, with a non-evaluable risk of recidivism. Subsequent evaluation showed a low recidivism risk based on clinical evolution. We discuss these findings considering existing literature and Swiss jurisprudence.

Affective music during episodic memory recollection modulates subsequent false emotional memory traces: an fMRI study.

Music is a powerful medium that influences our emotions and memories. Neuroscience research has demonstrated music's ability to engage brain regions associated with emotion, reward, motivation, and autobiographical memory. While music's role in modulating emotions has been explored extensively, our study investigates whether music can alter the emotional content of memories. Building on the theory that memories can be updated upon retrieval, we tested whether introducing emotional music during memory recollection might introduce false emotional elements into the original memory trace. We developed a 3-day episodic memory task with separate encoding, recollection, and retrieval phases. Our primary hypothesis was that emotional music played during memory recollection would increase the likelihood of introducing novel emotional components into the original memory. Behavioral findings revealed two key outcomes: 1) participants exposed to music during memory recollection were more likely to incorporate novel emotional components congruent with the paired music valence, and 2) memories retrieved 1day later exhibited a stronger emotional tone than the original memory, congruent with the valence of the music paired during the previous day's recollection. Furthermore, fMRI results revealed altered neural engagement during story recollection with music, including the amygdala, anterior hippocampus, and inferior parietal lobule. Enhanced connectivity between the amygdala and other brain regions, including the frontal and visual cortex, was observed during recollection with music, potentially contributing to more emotionally charged story reconstructions. These findings illuminate the interplay between music, emotion, and memory, offering insights into the consequences of infusing emotional music into memory recollection processes.

A Cadaveric Feasibility Study of the Biportal Endoscopic Transfrontal Sinus Approach: A Minimally Invasive Approach to the Anterior Cranial Fossa.

The trans-sinus transglabellar and bifrontal approaches offer direct access to the anterior cranial fossa. However, these approaches present potential drawbacks. We propose the biportal endoscopic transfrontal sinus (BETS) approach, adapting endoscopic endonasal approach (EEA) techniques for minimally invasive access to the anterior fossa, reducing tissue manipulation, venous sacrifice, and brain retraction. Six formalin specimens were used. BETS approach involves 2 incisions over the medial aspect of both eyebrows from the supraorbital notch to the medial end of the eyebrow. A unilateral pedicled pericranial flap is harvested. A craniotomy through the anterior table of the frontal sinus (FS) and a separate craniotomy through the posterior table are performed. Two variants of the approach (preservative vs cranialization) are described for opening and reconstruction of the FS based on the desired pathology to access. Bone flap replacement can be performed with titanium plates and filling of the external table defect with bone cement. Like in EEA, this approach provides access for endoscope and multiple working instruments to be used simultaneously. The approach allows wide access to the anterior cranial fossa, subfrontal, and interhemispheric corridors, all the way up to the suprachiasmatic corridor and through the lamina terminalis to the third ventricle. BETS provides direct access to the anterior fossa, minimizing the level of frontal lobe retraction and providing potentially less tissue disruption and improved cosmesis. Cerebrospinal fluid fistula risk remains one of the major concerns as the narrow corridor limits achieving a watertight closure which can be mitigated with a pedicled flap. Mucocele risk is minimized with full cranialization or reconstruction of the FS. The BETS approach is a minimally invasive approach that translates the concepts of EEA to the FS. It allows excellent access to the anterior cranial fossa structures with minimal frontal lobe retraction.

Clinical characteristics and multimodal imaging can help diagnosing and treating mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy.

Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE) is a recently described, histopathologically and molecularly defined (SLC35A2-mutated) type of cortical malformation. Although increasingly recognized, the diagnosis of MOGHE remains a challenge. We present the characteristics of the first six patients diagnosed in Bulgaria, with the aim to facilitate identification, proper presurgical evaluation, and surgical treatment approach in this disease. Revision of histopathological specimens of 202 patients operated on for drug-resistant focal epilepsy identified four cases with MOGHE. Another two were suggested, based on clinical characteristics and subsequently, were histologically confirmed. Sanger SLC35A2 sequencing on paraffin-embedded or fresh-frozen brain tissue was performed. Analysis of seizure types, neuropsychological profiles, electroencephalographic (EEG), imaging features and epilepsy surgery outcomes was done. Three out of the six cases (50%) harbored pathogenic SLC35A2 mutations. One patient had a heterozygous somatic variant with uncertain significance. Clinical characteristics included epilepsy onset in infancy (in 100% under 3 years of age), multiple seizure types, and moderate or severe intellectual/developmental delay. Epileptic spasms with hypsarrhythmia on EEG were the initial seizure type in five patients. The subsequent seizure types resembled those in Lennox-Gastaut syndrome. The majority of the patients (n = 4) presented prominent and persisting autistic features. Magnetic resonance imaging (MRI) showed multilobar (n = 6) and bilateral (n = 3) lesions, affecting the frontal lobes (n = 5; bilaterally in three) and characterized by increased signal on T2/fluid-attenuated inversion recovery (FLAIR). Voxel-based morphometric MRI post-processing and positron emission tomography helped determining the localization and extent of the lesions and presumed epileptogenic zones. After surgery, four patients (66.7%) were seizure-free ≥2 years. Interestingly, all seizure-free patients carried somatic SLC35A2-alterations. Epileptic spasms, early prominent neuropsychological disturbances, MRI-T2/FLAIR hyperintense lesions with cortico-subcortical blurring, frequently multilobar and especially frontal, can preoperatively help to suspect MOGHE. Epilepsy surgery is still the only successful treatment option in MOGHE.

Impact of Frontal Lobe Surgeries on Personality and Mood: A Comprehensive Review

Impact of Frontal Lobe Surgeries on Personality and Mood: A Comprehensive Review

Awake Craniotomy for Astrocytoma in the Left Frontal Lobe Using Augmented Reality Superimposing Tumor and White Matter Tracts: 2-Dimensional Operative Video.

Augmented reality (AR) is expected to serve as an assistive intraoperative technology in neurosurgery.1 Awake craniotomy (AC) for gliomas benefits the extent of resection, survival, and postoperative neurofunctional outcomes.2 In AC, it is critical to understand the cortical and subcortical anatomy.3 We describe the use of AR superimposing tumor and deep white matter tracts in AC. A 29-year-old right-handed woman presented to a local hospital after an episode of generalized convulsions. MRI of the head revealed a widely spreading tumor in the left middle frontal gyrus. After a left frontal craniotomy while the patient was asleep, AR was used to indicate the tumor boundary with subcortical fibers including the corticospinal tract, inferior fronto-occipital fasciculus, and cingulate fasciculus. We performed AR-assisted removal of the tumor on the surface of the middle frontal gyrus. On subcortical stimulation (SCS) of the frontal aslant tract and inferior fronto-occipital fasciculus, the patient stopped naming objects in the picture-naming test, while SCS of the left cingulate gyrus caused the patient to mistake colors in the Stroop test. The subcortical fibers identified by AR coincided with the sites of symptom elicitation by SCS. We eventually removed a large part of the tumor. Postoperative MRI confirmed 96.2% resection. The patient was discharged without any new neurological deficits. AC with AR is useful for resection of gliomas in the dominant hemisphere. The patient consented to the procedure and to the publication of her image. The ethics committee of our hospital does not require approval for case reports.