Anatomical Organization of the Amygdala: A Brief Visual Review.

The amygdala consists of a collection of nuclei that are deep within the medial temporal lobe. Despite its small size, the amygdala is one of the most densely connected structures in the brain, and it plays a role in many superior neural functions, including neurovegetative control, motor control, memory processing, and neuromodulation. Advances in neuroimaging technology for examining brain activity have opened up new ways of understanding the functional contribution of this structure to emotions, learning, and related memories. Many studies have shown that the amygdala plays a key role in the pathophysiology of neuropsychiatric disorders, such as anxiety disorders, depression, aggression, and temporal epilepsy. This article reviews the anatomical structure of the amygdaloid complex and the connectivity among its subdivisions and with other brain structures, which will serve as a basis for understanding the clinical correlations.

Identification of CD114 Membrane Receptors as a Molecular Target in Medulloblastomas.

Medulloblastomas are the most common solid tumors in children, accounting for 8-30% of pediatric brain cancers. It is a high-grade tumor with aggressive behavior and a typically b poor prognosis. Its treatment includes surgery, chemotherapy, and radiotherapy, and presents high morbidity. Significant clinical, genetic, and prognostic differences exist between its four molecular subgroups: WNT, SHH, Group 3, and Group 4. Many studies seek to develop new chemotherapeutic agents for medulloblastomas through the identification of genes whose expressions are new molecular targets for drugs, such as membrane receptors associated with cell replication. This study aimed to assess the association of CD114 expression with mortality in patients with medulloblastoma. Databases from the Medulloblastoma Advanced Genomics International Consortium (MAGIC) were analyzed, focusing on the expression of the CD114 membrane receptor in different molecular types and its possible association with mortality. Our findings showed different CD114 expressions between Group 3 and other molecular groups, as well as between the molecular subtypes SHH γ and Group 3 α and Group 3 ß. There was no statistically significant difference between the other groups and subtypes. Regarding mortality, this study did not find statistical significance in the association between low and high CD114 expressions and mortality. Medulloblastoma is a heterogeneous disease with many subtype variations of its genetic and intracellular signaling pathways. Similarly to this study, which could not demonstrate different CD114 membrane receptor expression patterns between groups, others who sought to associate CD114 expression with mortality in other types of cancer failed to establish a direct association. Since many indications point to the relation of this gene with cancer stem cells (CSCs), it may be part of a more extensive cellular signaling pathway with an eventual association with tumor recurrence. This study found no direct relationship between CD114 expression and mortality in patients with medulloblastoma. Further studies are needed on the intracellular signaling pathways associated with this receptor and its gene (the CSF3R).

Anatomical aspects and technical note of a modified retropharyngeal approach and reconstruction of the anterior occipitocervical junction.

Surgery to expose the anterior occiptocervical junction (OCJ) is exacting, and optimal approaches are debatable. The close proximity of vital structures and difficult surgical access present a unique challenge to treat lesions in this area. Routine access to the upper anterior cervical spine remains limited. The authors present a modified retropharyngeal approach and instrumentation in order to resect an exceptionally rare atypical rhabdoid teratoid tumor involving the craniovertebral junction. The technical aspects of this approach in anatomical perspectives are discussed in this article.

Microsurgical anatomy of language.

The localizationist model, which focused on classical cortical areas such as Broca's and Wernicke's, can no longer explain how language processing works. Over recent years, several studies have revealed new language-related cortical and subcortical areas, resulting in a transition from localizationist concepts to a hodotopical model. These studies have described language processing as an extensive and complex network of multiple interconnected cortical areas and subcortical pathways, differing from the classical circuit described by the localizationist perspective. The hodotopical model was made possible by a paradigm shift in the treatment of cerebral tumors, especially low-grade gliomas: total or subtotal tumor resections with cortical and subcortical mapping on awake patients have become the gold standard treatment for lesions located in the dominant hemisphere. In this article, we review current understating of the microsurgical anatomy of language.

Anterior Skull Base Tumors: The Role of Transfacial Approaches in the Endoscopic Era.

The basis of craniofacial tumor surgery is complete surgical extirpation, preferably en bloc or with free borders. Craniofacial techniques are the gold standard and primary strategies in the treatment of anterior skull base tumors. In the last decade, the reports favoring results of endoscopic techniques have increased. One could conclude that the classical transfacial approaches might become useless, but, in fact, there is little research comparing these techniques.In this article, the authors present their experience with combined craniofacial resection of anterior craniofacial skull base tumors in 9 consecutive patients between January 2013 and July 2015. This article aims to review some of the traditional transfacial approaches, illustrating them with this series of surgical patients. Benefits and drawbacks of these approaches are discussed.

Computed tomography imaging study of the superior attachment of the uncinate process.

BACKGROUND: The superior attachment of the uncinate process (SAUP) is an important landmark in the nasofrontal recess, but its anatomical distribution is still unclear. The objective of this study was to assess the location and number of superior attachments of the uncinate process on computed tomography (CT) images. METHODOLOGY: A cross-sectional, retrospective study conducted at the Department of Radiology, Hospital de Clinicas de Porto Alegre, Brazil. Sinus CT scans of adult patients with no history of sinonasal surgery, craniofacial fractures, malignant neoplasms, or malformations were examined for identification of the site of SAUP. RESULTS: 152 CT scans (304 sides) were assessed. The SAUP was appropriately identified in 292 sides (96%). Six distinct SAUP patterns were identified: to the lamina papyracea or anterior ethmoidal cells (193, 63.48%); to the middle turbinate (19, 6.25%); to the skull base (19, 6.25%); to the lamina papyracea and middle turbinate (29, 9.53%); to the lamina papyracea and skull base (29, 9.53%); and to the skull base and middle turbinate (3, 0.98%). CONCLUSION: The site of superior attachment of the uncinate process is highly variable, but is in contact with the lateral nasal wall in 82.5% of the cases.

Asymmetry of the anterior ethmoidal artery in relation to the anterior skull base: a population-based study of 500 arteries.

OBJECTIVE: To analyze variability in the distance between the Anterior Ethmoidal Artery (AEA) and the anterior Skull Base (SB), as well as the frequency of lateral asymmetry in a Latin American population using computed tomography. METHODS: A total of 250 computed tomography scans of paranasal sinuses in coronal reconstruction (500 AEAs) were analyzed. After determining the image with the best anatomical view of the artery, the distance between its midpoint and the ethmoidal roof was measured, and the images were independently interpreted by 2 physicians. RESULTS: Of the 500 AEAs, 279 (55.8%) adhered to or passed through the SB at a distance of 0mm. A total of 221 AEAs (44.2%) were at some distance from the SB, of which 107 (48.4%) were on the right side, ranging from 1.18 to 6.75mm, and 114 (51.5%) were on the left side, ranging from 1.15 to 6.04mm. The overall mean distance between the AEA and SB was 1.22 (SD=1.57) mm, increasing to 2.77 (SD=1.14) when the arteries adhered to the SB were excluded. Seventy-six individuals (30.4%) had a lateral distance variation > 1mm. CONCLUSION: Our study includes the largest sample of AEA analyzed with computed tomography scans of paranasal sinuses. There was some distance between the AEA and SB in almost half the patients, and we found a high rate of lateral variability >1mm. LEVEL OF EVIDENCE: Level 3.

Endoscopic anatomy of sellar region.

The transsphenoidal approach is the preferred access used in surgical treatment of most sellar region pathologies. The use of endoscopy is advantageous, and it is considered a good alternative to the traditional microsurgical technique. The purpose of this study is to recognize and describe anatomical variations of the sphenoid sinus and the sellar region, mainly describing the anatomy of the posterior wall of the sphenoid sinus and analyzing intercarotid distances in 3 regions. Thirty sphenoid blocks treated with formaldehyde were injected and dissected. Using endoscopy, anatomical variations were studied and the intercarotid distances were measured at the tuberculum sellae, sellar floor and clivus. The types of sphenoid sinus found were: conchal in 1 (4.76 %), pré-sellar in 2 (9.52 %) and sellar in 19 (85.7 %) specimens. The mean distance found from the sphenoid sinus ostium to the sella turcica was 19 mm (±6.5) mm. The mean intercarotid distances found at the tuberculum sellae, sellar floor and clivus were respectively 13.32, 18.00 and 18.90 mm. Endoscopy, with its magnification and lighting provide a panoramic view of deep fields. The anatomical variations described in this study support the need for a careful evaluation of preoperative images in each case.

Prolong intermittent injection of human parathyroid hormone in rats modulates the expression of several proteins in the neuropil of the cerebellar cortex.

INTRODUCTION: The intermittent use of recombinant human parathyroid hormone (iPTH) alters calcium metabolism and induces osteogenesis in experimental models. However, the real effects of iPTH in excitable cells and neurons that require membrane receptors to undergo membrane depolarization/repolarization (Na+K+ATPase) to generate ATP, voltage-gated calcium channel (calcium-IP3R-calponin) as well as GABAergic (GABAA) signaling remains unclear. OBJECTIVES: In this study, the expression of IP3R, Na+K+-ATPase, GABAA and calmodulin proteins were evaluated in histological sections of the cerebellum of rats following prolonged injection of iPTH. METHODS: Twenty Wistar rats were used in this study and randomly assigned as either or control group. The test group were subcutaneously injected with 20 µg/kg of iPTH, 3×/week for 8 weeks, while the control group received 1 ml/kg of 0.9% saline solution. The rats were euthanized on the 60th day after the first administration, and their cerebellar vermis was removed and submitted to histological and immunohistochemical evaluation for detection of IP3R, Na+K+-ATPase, GABAA and calmodulin proteins. The expression of proteins was evaluated in the areas corresponding to the Purkinje cells as well as in neuropil of molecular layer of cerebellum. All results were transformed into a percentage for each area analyzed to verify significance between groups. RESULTS: Rats that received iPTH demonstrated significant reduction of IP3R, calmodulin and GABAA in Purkinje cells and neuropil of molecular layer while the expression of Na+K+-ATPase was similar. CONCLUSION: It was concluded that iPTH decreased the expression of IP3R and calmodulin while it did not alter the expression of Na+K+-ATPase. These changes insinuate the ionic activity of calcium and sodium/potassium. Yet, the iPTH alters GABAergic signaling in Purkinje cells, suggesting neurotransmission activity changes in the cerebellum.

The Posterior Inferior Cerebellar Artery (PICA): An Anatomical and Clinical Analysis.

AIM: To study the operative approaches for posterior inferior cerebellar artery (PICA) aneurysms or understanding the different pathologies that can affect this artery, and to present detailed knowledge of this artery?s anatomy. MATERIAL AND METHODS: The present study analyzed the different variations of the PICA?s first two segments, the anterior medullary and lateral medullary segments, regarding the number of trunks, their emergency site, and the presence or absence of hypoplasia of this artery, through microsurgical dissection of 23 fresh cadaver brains. RESULTS: Some striking variations were found, such as the absence of the left vertebral artery in one of the brains and the emergence of any PICA in another two brains studied. Moreover, variations such as hypoplastic arteries, missing trunks on one side and double or triple trunks, different emergence sites, significant PICA emergence from the superior part of the vertebral artery (59% of the trunks), and asymmetries between the right and left sides were recorded. The double origins of non-hypoplastic PICAs were found in 17% (n = 4) of patients. CONCLUSION: The results obtained in the present study indicated the great importance of the studies and reviews on the different topographies of PICA; these studies and reviews expand the knowledge and consensus on the characteristics and implications of PICA?s variations. The clinical implication of this knowledge and consensus is obtaining the best surgical strategies for clipping aneurysms and, in addition, the best choices for occlusion of the vessel affected if the territory of the main vessel has an adequate collateral circulation. From the results of the present study, it is evident that there was a significant PICA emergence from the superior part of the vertebral artery and that the double origin of non-hypoplastic trunks was also found in some patients; the latter is associated with a greater chance of aneurysms and other additional complications.

[Surgical Approaches to Petroclival Meningiomas Part 1: Microsurgical Anatomy]. / Abordajes quirúrgicos de meningiomas petroclivales parte 1: anatomía microquirúrgica.

Background: Most petroclival meningiomas are benign tumors, but their neurosurgical treatment is one of the greatest challenges in this field. Acquiring a deep practical knowledge of brain anatomy is the first step on the path to successfully meeting this challenge. To this end, the present paper is divided into two parts. The first regards the microsurgical anatomy and surgical approaches used in the management of petroclival meningiomas. The second correlates the brain anatomies of the 30 cases of petroclival meningiomas which the senior author (GRI) has operated on. Methods: Eight cadaver heads were dissected using surgical microscopes at the University of Arkansas microsurgery laboratory. The heads were stabilized in a Mayfield device to simulate surgical conditions and colored silicon was injected to highlight the differences between arteries and veins. The approaches performed were: cranio-orbital zygomatic, posterior and anterior petrosectomy, and retrosigmoid. Results: Three main surgical approaches were chosen to treat petroclival meningiomas: the pterional approach and its variants, the petrous approach and its variants, and the retrosigmoid approach. To rationalize the choice of approach, the clivus was separated into superior, middle, and inferior thirds. Conclusion: Several surgical approaches are useful in accessing the petroclival region. Acquiring a practical knowledge of this anatomy in a microsurgical laboratory is fundamental for any surgeon who intends to operate on petroclival meningiomas.

Anatomy of the optic radiations from the white matter fiber dissection perspective: A literature review applied to practical anatomical dissection.

Background: Knowledge of the anatomical course of the optic radiations and its relationship to medial temporal lobe structures is of great relevance in preoperative planning for surgery involving the temporal lobe to prevent damage that may result in postsurgical visual field deficits. Methods: In this anatomical study, we reviewed the literature on this topic and applied the information to practical anatomical dissection. The three-dimensional relationship between the course of the optic radiations and structures accessed in the main microneurosurgical approaches to the medial temporal lobe was examined by applying Klingler's white matter fiber dissection technique to five formalin-fixed human brains. The dissections were performed with an operating microscope at magnifications of ×3-×40. High-resolution images were acquired during dissection for identification of the anatomical structures, focusing on the characterization of the course of the optic radiations in relation to medial temporal lobe structures. Results: In all five dissected brains, we could expose and clearly define the relationship between the optic radiations and medial temporal lobe structures, improving our understanding of these complex structures. Conclusion: The knowledge gained by studying these relationships will help neurosurgeons to develop risk-adjusted approaches to prevent damage to the optic radiations in the medial temporal region, which may result in a disabling visual field deficit.

Avoiding vascular complications in insular glioma surgery - A microsurgical anatomy study and critical reflections regarding intraoperative findings.

Introduction: Vascular lesions in insular glioma surgery can severely impact patients' quality of life. This study aims to present the results of our dissections and authors' reflections on the insular vascular anatomy. Matherials and Methods: The insular vascularization was examined using ×3 to ×40 magnification in 20 cadaveric cerebral hemispheres in which the arteries and veins had been perfused with colored silicone. Results: In insular gliomas, this individualization of the anatomical structures is rarely possible, as the gyri are swollen by the tumor and lose their individuality. In the transsylvian approaches, the anatomical parameters for delimiting the insula in tumors are best provided by the superior and inferior circular sulci. The branches of the MCA are easily identified in the transcortical approach, but only at the end of the surgery after the tumor is resected.). One of the factors under-discussed in the literature is the involvement of the lenticulostriate arteries by the medial part of the tumor. In our experience of 52 patients (article submitted to publishing), LSTa were founded to be involved by the tumor in 13 cases. In 39 patients, there was no involvement of the LSTa, which allowed a more aggressive resection. Early preoperative identification of the anterior perforated substance on the MRI and its proximity to the tumor may help determine the route of the LSTa over the medial tumor boundaries. Discussion: Our reflections introduced our imaging and anatomical concept regarding LSTa in insular glioma surgery. Accurate identification of origin, route, and distribution of the LSTa is pivotal to surgical success, especially in the lateral group. The anatomical knowledge of their path directly impacts the extent of tumor resection and functional preservation. Conclusion: Knowledge of microsurgical anatomy, brain mapping, and surgical experience counts a lot in this type of surgery, creating a reasonable procedure flowchart to be taken intraoperatively.

[Surgical approaches to petroclival meningiomas Part 2: narrative review of what we learned with 30 cases]. / Abordajes quirúrgicos de los meningiomas petroclivales Parte 2: revisión narrativa y lo que aprendimos con 30 casos.

Background: The surgical ressection of petroclival meningiomas is challenging due to its deep location and relationship with vital neurovascular structures. Usually they are benign injuries, but they can involve or infiltrate skull base bones, dura mater and brainstem. This makes the total removing very difficult or impossible without causing neurological deficits. The objective of this study is to review the surgical approaches used on the treatment of petroclival meningiomas and the knowledge which we achieved upon the surgical management of 30 cases. Methods: Series of 30 petroclival meningioma-cases. In the beginning of our series we used petrous approach for all the cases, however, with the acquiring of experience, we are indicating the retrosigmoid approach, leaving the petrous and skull-orbito-zigomatics approaches for selected cases. Results: Owing to the difficulty of the access, the petroclival meningiomas usually require different surgical approaches and have distint surgical difficulties. There are three main approaches: fronto-orbito-zigomatics and variants; petrous and variants and retrosigmoid, and they can be combined. The choice for a surgical approach is usually on the location and size of the tumor, on the skull shape, the involvement of venous structures and according to the surgeon´s experience. Conclusion: Petroclival meningiomas are rare and complex on the skull base. The adequate choice is crucial to achieve the good surgical result.

Image-guided Temporal Bone Dissection Course.

Introduction Temporal bone anatomy is complex and demands a profound anatomical knowledge. Association between surgery and imaging helps in the process of learning three-dimensional (3D) anatomy and surgical techniques. High definition temporal bone imaging can play an important role in dissection training. Objective To describe a computed tomography (CT) image-guided temporal bone dissection course for surgical training in otolaryngology and to verify the satisfaction level of the students with the course. Methods Descriptive research. The course took place at a research laboratory, with three experienced temporal bone surgeons. The participants were 12 otolaryngology residents. The laboratory has 7 modern workstations with microscope and monitors linked with a computerized video system. Cadaveric temporal bones were donated to the university. Imaging acquisition of the cadaveric temporal bones used in the course was performed in a multislice CT scanner. The CT images of cadaveric temporal bones were available with real-time access on the laboratory monitor's screens during dissections. Results A total of 13 temporal bones were included for dissection. Students had the opportunity to view on the same screen, simultaneously, both the dissection video and the respective CT images of their temporal bone anatomical specimens. This allowed correlating surgical and imaging aspects of temporal bone anatomy. At the end of the course, participants answered a satisfaction survey. Conclusion Considering imaging methods are routinely used during most otologic surgeries, detailed knowledge of CT imaging should be explored in conjunction with the temporal bone anatomical dissection.

Vascularization of the uncus - Anatomical study and clinical implications.

BACKGROUND: The objective of this paper was to describe the arterial supply of the uncus and quantify the branches directed to the anteromedial aspect of the human temporal cortex. METHODS: We studied 150 human cerebral hemispheres identifying main afferent arteries supplying the anteromedial temporal cortex with particular attention to the uncus, determining the territory supplied by each artery through either cortical or perforating branches. RESULTS: The uncus was supplied by 419 branches of the anterior choroidal artery (AChA), 210 branches of the internal carotid artery (ICA), 353 branches of the middle cerebral artery (MCA), and 122 branches of the posterior cerebral artery (PCA). The total of supplying vessels was 1104 among the 150 hemispheres studied, which corresponds to 7.36 arteries per uncus. The average of branches per hemisphere was as follows: 2.79 from AChA, 1.40 from ICA, 2.35 from MCA, and 0.81 from PCA. The relative contribution of each artery for the total of specimens studied was as follows: 38% from AChA, 19% from ICA, 32% from the MCA, and 11% from the PCA. We identified cortical anastomoses mostly between the MCA and PCA (27 cases). CONCLUSION: We described and quantified the uncus' vascularization, including anatomical variations. This updated, detailed description of the mesial temporal vascularization is paramount to improve the treatment of neurosurgical conditions.

Musical hallucinations following insular glioma resection.

Hallucinations can be auditory, visual, tactile, gustatory, or olfactory, and can be caused by psychiatric (such as schizophrenia and depression), neurological (such as cerebrovascular accidents, neoplasia, and infection), or endocrine and metabolic disorders. Musical hallucinations related to neurological disorders are rare. The authors present a case of a patient with a right insular glioma who developed transient musical hallucinations after microsurgical resection of the tumor.

Hippocampal vascularization: Proposal for a new classification.

BACKGROUND: Anatomy of the hippocampal arterial supply is key to successful surgeries in this area. The goal of the current study is to present the results we obtained from our microsurgical dissections of the temporal lobe and to propose a new classification for the hippocampal arteries (HAs). METHODS: Fifty-six brain hemispheres were analyzed. All dissections in this study were made using 3-40× at the surgical microscope. RESULTS: The hippocampal arterial vasculature can be divided into six groups, according to their frequencies: Group A: mixed arterial vasculature originating from the anterior choroidal artery anterior choroidal artery, posterior cerebral artery (PCA), anterior infratemporal artery (AIA), and splenic artery (SA). Group B: Main origin at the temporal branches - main inferotemporal trunk, middle inferotemporal artery, posterior inferotemporal artery, AIA, or main branch of PCA. Group C: AIA as the main branch of the hippocampus. Group D: HAs originating from the main branch of PCA. Group E: A single hippocampal artery with the origin at the main branch of PCA. This single artery covered all of the structure and is named Ushimura's artery. Group F: The hippocampal vessels arose exclusively from the parieto-occipital artery, calcarine artery (CA), and the SA. CONCLUSION: This study proposes a new classification for the hippocampal vascularization, according to the origin of HAs. One of the groups has not yet been described in the literature - in which the HAs arise from the parieto-occipital artery, SA, and CA.

The implications of microsurgical anatomy for surgical approaches to the sellar region.

The knowledge of the normal anatomy and variations regarding the management of tumors of the sellar region is paramount to perform safe surgical procedures. The sellar region is located in the center of the middle cranial fossa; it contains complex anatomical structures, and is the site of various pathological processes: tumor, vascular, developmental, and neuroendocrine. We review the microsurgical anatomy (microscopic and endoscopic) of this region and discuss the surgical nuances regarding this topic, based on anatomical concepts.

Asymmetry of the anterior ethmoidal artery in relation to the anterior skull base: a population-based study of 500 arteries

Abstract Objective To analyze variability in the distance between the Anterior Ethmoidal Artery (AEA) and the anterior Skull Base (SB), as well as the frequency of lateral asymmetry in a Latin American population using computed tomography. Methods A total of 250 computed tomography scans of paranasal sinuses in coronal reconstruction (500 AEAs) were analyzed. After determining the image with the best anatomical view of the artery, the distance between its midpoint and the ethmoidal roof was measured, and the images were independently interpreted by 2 physicians. Results Of the 500 AEAs, 279 (55.8%) adhered to or passed through the SB at a distance of 0 mm. A total of 221 AEAs (44.2%) were at some distance from the SB, of which 107 (48.4%) were on the right side, ranging from 1.18 to 6.75 mm, and 114 (51.5%) were on the left side, ranging from 1.15 to 6.04 mm. The overall mean distance between the AEA and SB was 1.22 (SD = 1.57) mm, increasing to 2.77 (SD = 1.14) when the arteries adhered to the SB were excluded. Seventy-six individuals (30.4%) had a lateral distance variation > 1 mm. Conclusion Our study includes the largest sample of AEA analyzed with computed tomography scans of paranasal sinuses. There was some distance between the AEA and SB in almost half the patients, and we found a high rate of lateral variability >1 mm. Level of evidence: Level 3.