Leksell Frame-Based Stereotactic Biopsy for Infratentorial Tumor : Practical Tips and Considerations

The Leksell frame-based transcerebellar approach was proposed with the arc support frame attached upside down to the Z coordinate. This study presented practical tips and considerations for obtaining adequate tissue samples for deep-seated cerebellar lesions or lower brainstem lesions specifically those accessible via the cerebellar peduncle. For practical insights, the Leksell coordinate frame G was fixed to prevent the anterior screw implantation within the temporalis muscle, to avoid interference with the magnetic resonance (MR)-adapter, and taking into account the magnetic field of MR in close proximity to the tentorium. After mounting of indicator box, the MR imaging evaluation should cover both the indicator box and the infratentorial region that deviated from it. The coordinates [X, Y, Za, Arc0, Ringa0] obtained from Leksell SurgiPlan® software (Elekta, Stockholm, Sweden) with arc 00 located on the patient's right side were converted to [X, Y, Zb=360-Za, Arc0, Ringb0=Ringa0-1800]. The operation was performed in the prone position under general anesthesia in four patients with deep cerebellar (n=3) and brainstem (n=1) tumors. The biopsy results showed two cases of diffuse large B-cell lymphoma, one metastatic braintumor and one glioblastoma. One patient required frame repositioning as a complication. Drawing upon the methodology outlined in existing literature, we anticipate that imparting supplementary expertise could render the stereotactic biopsy of infratentorial tumors more consistent and manageable for the practitioner, thereby facilitating adequate tissue samples and minimizing patient complications.

Exploring Brainstem Structural Abnormalities: Potential Biomarkers for Panic Disorder

Panic disorder (PD), characterized by recurrent and intense panic attacks, presents a complex interplay between psychological and neurobiological factors. Although the amygdala and hippocampus have been studied extensively in the context of PD, the brainstem's involvement remains relatively underexplored. This study aims to address this gap by examining structural abnormalities within specific brainstem regions, including the medulla, pons, and midbrain. The study sample population comprised twenty-one adult patients diagnosed with PD and an age-gender-education-matched control group. Utilizing rigorous inclusion and exclusion criteria, confounding factors related to comorbid psychiatric conditions and brain structure abnormalities were minimized. Our findings revealed a significant reduction in medulla volume among PD patients, a finding that persisted even after correcting for individual differences in total intracranial volume. The medulla's role in cardiovascular regulation and autonomic function, coupled with its involvement in fear responses, underscores its potential significance in the pathophysiology of PD. This study elucidates the medulla's structural abnormalities as a potential biomarker for PD. Understanding the role of the brainstem in PD could pave the way for more targeted and effective interventions for this condition.

Survival outcomes and prognostic factors of infratentorial glioblastoma in the elderly

INTRODUCTION

Infratentorial glioblastoma(itGBM) is a rare and rapidly progressive form of GBM with poor prognosis. However, no studies have adequately examined itGBM outcomes in elderly patients (>65 years). Here, we used a national database to fill this knowledge gap.

METHODS

SEER 18 registries were utilized to identify adult itGBM patients diagnosed between 2000-2016. itGBM cases were further divided into cerebellar and brainstem GBM as cGBM and bGBM, respectively. Kaplan-Meier analysis and Cox hazards proportional regression models were performed to assess factors associated with overall survival (OS).

RESULTS

Among 137 (33%) elderly patients from the study cohort (N = 420), median age was 74 years, 38% were female, and 85% were white. Median OS in elderly itGBM patients was shorter than younger adults (10 vs. 5-months, p < 0.001). Multivariate analysis by tumor location revealed that older age was associated with poor survival for cGBM, but not for bGBM. Gross-total resection (GTR) was associated with better outcomes for both cGBM and bGBM. Radiotherapy had survival benefits for cGBM; meanwhile, chemotherapy prolonged OS in bGBM. In the elderly, advanced age (80 + years) was associated with poor outcomes, while GTR, CT and RT were all associated with improved survival.

CONCLUSIONS

In our study, while elderly patients had worse survival compared to younger adults for both cGBM and bGBM, GTR improved OS in elderly itGBM, with CT and RT exhibiting a location-dependent survival benefit. Thus, elderly itGBM patients should undergo a combination of maximal resection and adjuvant treatment guided by infratentorial tumor location for maximal survival benefit.

Brainstem anatomy with 7-T MRI: in vivo assessment and ex vivo comparison

BACKGROUND

The brainstem contains grey matter nuclei and white matter tracts to be identified in clinical practice. The small size and the low contrast among them make their in vivo visualisation challenging using conventional magnetic resonance imaging (MRI) sequences at high magnetic field strengths. Combining higher spatial resolution, signal- and contrast-to-noise ratio and sensitivity to magnetic susceptibility (χ), susceptibility-weighted 7-T imaging could improve the assessment of brainstem anatomy.

METHODS

We acquired high-resolution 7-T MRI of the brainstem in a 46-year-old female healthy volunteer (using a three-dimensional multi-echo gradient-recalled-echo sequence; spatial resolution 0.3 × 0.3 × 1.2 mm3) and in a brainstem sample from a 48-year-old female body donor that was sectioned and stained. Images were visually assessed; nuclei and tracts were labelled and named according to the official nomenclature.

RESULTS

This in vivo imaging revealed structures usually evaluated through light microscopy, such as the accessory olivary nuclei, oculomotor nucleus and the medial longitudinal fasciculus. Some fibre tracts, such as the medial lemniscus, were visible for most of their course. Overall, in in vivo acquisitions, χ and frequency maps performed better than T2*-weighted imaging and allowed for the evaluation of a greater number of anatomical structures. All the structures identified in vivo were confirmed by the ex vivo imaging and histology.

CONCLUSIONS

The use of multi-echo GRE sequences at 7 T allowed the visualisation of brainstem structures that are not visible in detail at conventional magnetic field and opens new perspectives in the diagnostic and therapeutical approach to brain disorders.

RELEVANCE STATEMENT

In vivo MR imaging at UHF provides detailed anatomy of CNS substructures comparable to that obtained with histology. Anatomical details are fundamentals for diagnostic purposes but also to plan a direct targeting for a minimally invasive brain stimulation or ablation.

KEY POINTS

• The in vivo brainstem anatomy was explored with ultrahigh field MRI (7 T). • In vivo T2*-weighted magnitude, χ, and frequency images revealed many brainstem structures. • Ex vivo imaging and histology confirmed all the structures identified in vivo. • χ and frequency imaging revealed more brainstem structures than magnitude imaging.

Prenatal diagnosis of Poland-Möbius syndrome by multimodality fetal imaging

We describe prenatal diagnosis of Poland-Möbius syndrome using a combination of ultrasound and MRI. Poland syndrome was diagnosed based on absence of the pectoralis muscles associated with dextroposition of the fetal heart and elevation of the left diaphragm. Associated brain anomalies that led to the diagnosis of Poland-Möbius syndrome, included ventriculomegaly, hypoplastic cerebellum, tectal beaking, and a peculiar flattening of the posterior aspect of the pons and medulla oblongata, which has been reported by postnatal diffusion tensor imaging studies as a reliable neuroimaging marker for Möbius syndrome. Since abnormalities of cranial nerves VI and VII may be difficult to detect prenatally, careful attention to the appearance of the brain stem as illustrated in the current report may aid in the prenatal diagnosis of Möbius syndrome.

Normal measurements of brainstem and related structures for all ages: An MRI-based morphometric study

Background

Knowledge of the normal size of the brain stem and certain related structures play an important role in diagnosis of aging and neurodegenerative conditions affecting the brain. There is no well-established normative data for development and age-related changes pertaining to the brain stem and related structures in the Indian context. The objective of this study was to assess various linear and angle measurements of the brain stem, cerebral peduncles, middle cerebellar peduncles, and proximal cervical cord for all ages in patients who have undergone MRI brain for unrelated pathologies.

Methods

A record-based retrospective cross-sectional and analytical study. T1WI axial and sagittal images were studied for the following variables: Cerebral peduncle transverse thickness, Interpeduncular angle, Middle cerebellar peduncle transverse thickness, Ventral midbrain anteroposterior thickness, Midbrain height, Mamillopontine distance (MPD), Pontomesencephalic angle (PMA), Pons anteroposterior thickness, Medulla anteroposterior thickness and Spinal cord anteroposterior diameter.

Results

Significant differences (p = 0.001) were observed in nearly all the variables among various age groups. Males demonstrated significantly higher mean values (at 5% level of significance) for a majority of the variables. Most of the variables measured, e.g. Cerebral peduncle, Middle cerebellar peduncle, Ventral midbrain thickness, Midbrain height, Pons, Medulla, and Spinal Cord diameter, showed a steady and sharp increase in values from infancy and reached maximum values during the third decade, followed by a variable degree of decline in values.

Conclusion

Magnetic Resonance Imaging (MRI) morphometry of brainstem and related structures is easily doable and is also reproducible. Present study lays down normative data for the brainstem and certain related structures for all ages, which can be referred to in day-to-day practice.

Stereotactic radiosurgery outcome for deep-seated cerebral arteriovenous malformations in the brainstem and thalamus/basal ganglia: systematic review and meta-analysis

Deep-seated unruptured AVMs located in the thalamus, basal ganglia, or brainstem have a higher risk of hemorrhage compared to superficial AVMs and surgical resection is more challenging. Our systematic review and meta-analysis provide a comprehensive summary of the stereotactic radiosurgery (SRS) outcomes for deep-seated AVMs. This study follows the guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We conducted a systematic search in December 2022 for all reports of deep-seated arteriovenous malformations treated with SRS. Thirty-four studies (2508 patients) were included. The mean obliteration rate in brainstem AVM was 67% (95% CI: 0.60-0.73), with significant inter-study heterogeneity (tau2 = 0.0113, I2 = 67%, chi2 = 55.33, df = 16, p-value < 0.01). The mean obliteration rate in basal ganglia/thalamus AVM was 65% (95% CI: 0.58-0.72) with significant inter-study heterogeneity (tau2 = 0.0150, I2 = 78%, chi2 = 81.79, df = 15, p-value < 0.01). The presence of deep draining veins (p-value: 0.02) and marginal radiation dose (p-value: 0.04) were positively correlated with obliteration rate in brainstem AVMs. The mean incidence of hemorrhage after treatment was 7% for the brainstem and 9% for basal ganglia/thalamus AVMs (95% CI: 0.05-0.09 and 95% CI: 0.05-0.12, respectively). The meta-regression analysis demonstrated a significant positive correlation (p-value < 0.001) between post-operative hemorrhagic events and several factors, including ruptured lesion, previous surgery, and Ponce C classification in basal ganglia/thalamus AVMs. The present study found that radiosurgery appears to be a safe and effective modality in treating brainstem, thalamus, and basal ganglia AVMs, as evidenced by satisfactory rates of lesion obliteration and post-surgical hemorrhage.

Biopsies of caudal brainstem tumors in pediatric patients - a single center retrospective case series

OBJECTIVE

The indication for performing biopsies in patients with diffuse lesions in the brain stem is controversial. Possible risks associated with the technical challenging interventions need to be balanced against clarifying the diagnosis and possible therapeutic options. We reviewed the feasibility, risk profile and diagnostic yield of different biopsy techniques in a pediatric cohort.

METHODS

We retrospectively included all patients under 18 years of age that received a biopsy of the caudal brainstem region (pons, medulla oblongata) at our pediatric neurosurgical center from 2009-2022.

RESULTS

We identified 27 children. Biopsies were performed using frameless stereotactic (Varioguide) (n=12), robotic assisted (Autoguide) (n=4), endoscopic (n=3) and open biopsy (n=8) technique. Intervention related mortality was not observed. Three patients experienced transient post-surgical neurological deficit. No patient showed intervention related permanent morbidity. Biopsy yielded histopathological diagnosis in all cases. Molecular analysis was feasible in 97% of cases. Most common diagnosis was H3K27M mutated diffuse midline glioma (60%). Low-grade gliomas were identified in 14%. Overall survival was 62.5% after 24 months of follow up.

CONCLUSION

Biopsies of the caudal brainstem in children were feasible and safe in the presented setup. The amount of acquired tumor material allowing integrated diagnosis and was obtained at reasonable risk. The selection of the surgical technique depends on tumor location and growth pattern. We recommend brainstem tumor biopsies in children being performed at specialized centers to better understand the biology and enable possible novel therapeutic options.

Medullary branches of the vertebral artery: microsurgical anatomy and clinical significance

BACKGROUND

Since the medullary arteries are of a great neurologic and neurosurgical significance, the aim was to perform a detailed microanatomic study of these vessels, as well as of the medullary infarctions in a group of patients.

METHODS

The arteries of 26 halves of the brain stem were injected with India ink and gelatin, microdissected and measured with an ocular micrometer. Neurologic and magnetic resonance imaging (MRI) examinations were performed in 11 patients.

RESULTS

The perforating medullary arteries, averaging 6.7 in number and 0.26 mm in diameter, most often originated from the anterior spinal artery (ASA), and rarely from the vertebral (VA) (38.5%) and the basilar artery (BA) (11.6%). They supplied the medial medullary region. The anterolateral arteries, 4.8 in number and 0.2 mm in size, most often arose from the ASA and PerfAs, and nourished the anterolateral region. The lateral arteries, 2.2 in number and 0.31 mm in diameter, usually originated from the VA and the posterior inferior cerebellar artery (PICA). They supplied the lateral medullary region. The dorsal arteries, which mainly arose from the PICA and the posterior spinal artery (PSA), nourished the dorsal region, including the roof of the 4th ventricle. The anastomotic channels, averaging 0.3 mm in size, were noted in 42.3%. Among the medullary infarctions, the lateral ones were most frequently present (72.8%).

CONCLUSION

The obtained anatomic data, which can explain the medullary infarctions symptomatology, are also important in order to avoid damage to the medullary arteries during neurosurgical and neuroradiologic interventions.

Brain stem encephalitis is a rare complication of COVID-19

Here, we describe the clinical phenotype of SARS-CoV-2-related CNS disease and evaluate the SARS-CoV-2 antibody index as a tool to differentiate between a direct (viral) and indirect etiology. Out of >4000 hospitalized patients with COVID-19, we included 13 patients with neurological symptoms with suspicion of neuroinflammation. On clinical grounds, eight were classified as having a possible/probable relationship between neurological symptoms and COVID-19. A clinically distinctive phenotype of brainstem and cerebellar symptoms was seen in 6/8 patients. As we found a positive SARS-CoV-2 antibody index in 3/5 patients, indicating specific intrathecal SARS-CoV-2 IgG production, a direct link with SARS-CoV-2 is likely.

Efficacy of Intravenous Immunoglobulins against Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids: A Case Report

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system that predominantly affects the brainstem. Apart from corticosteroids, there are few reported treatment options for CLIPPERS, and there is no standard therapy. A 77-year-old man presented with diplopia that had persisted for 5 months. Dysarthria and numbness of the distal right upper extremity and right lips were also observed. Brain magnetic resonance imaging (MRI) revealed a hyperintense area around the brainstem. Symptoms were relieved immediately following intravenous methylprednisolone (IVMP) administration. However, after gradual tapering of oral prednisolone to 5 mg/day, the symptoms relapsed, and brain imaging revealed that the condition had worsened. Intravenous immunoglobulins (IVIg) were administered for recurrence, with no clinical improvement. After each IVMP treatment, the patient recovered promptly. Based on the patient's symptoms and characteristic MRI findings, exclusion of other diseases, and the significant efficacy of corticosteroids, he was diagnosed with CLIPPERS. There was no recurrence at a maintenance prednisolone dose of 8 mg/day. IVIg had a poor effect on the acute phase of CLIPPERS symptoms. Compared with other immunosuppressants, IVIg is less effective in suppressing the relapse of CLIPPERS.

Effects of Ambient Acoustic Noise on Auditory Brainstem Response to Level-Specific Chirp and Click Stimuli in Normal-Hearing Adults

Background and Objectives

Despite few reports on the influence of ambient acoustic noise on auditory brainstem response (ABR) to click stimuli, its effects on ABR to level-specific (LS) stimuli have not been systematically investigated. This study aimed to investigate the influence of ambient acoustic noise on ABR findings using both LS chirp and click stimuli.

Subjects and Methods

Twelve normal-hearing adults participated in this repeated measure design study. The ABRs were acquired at 80, 50, and 30 dBnHL using two stimuli (LS chirp and click) under two conditions (quiet and noise). The ABRs under noise conditions were acquired using babble noise and white noise. The noise level was set at 55 dBA. Two-way repeated measure analysis was used to identify the main effects of the test conditions, stimulus types, and their interactions at a 95% confidence level.

Results

No significant influence of ambient acoustic noise on ABR findings was identified at all intensity levels. No significant difference was found in the number of signal averages to reach the 0.04 μV residual noise as stopping criteria among the ABRs recorded with different types of stimuli and test conditions. The ABR waves I and V amplitudes were larger with LS chirp than with click stimulus.

Conclusions

Ambient acoustic noise has no significant influence on ABR findings and the ABR test time based on the 55 dBA noise level used in this study.

Direct Removal of Fourth Ventricle Hematoma in Massive Intraventricular Hemorrhage

Various grading systems and surgical techniques have been developed for the treatment of intraventricular hemorrhage (IVH); however, little attention has been paid to the fourth ventricle hematoma. Nonetheless, hemorrhagic dilation of the fourth ventricle may lead to catastrophic consequences for patients with massive IVH. We present two cases of massive IVH accompanied by massive fourth ventricle hematoma which was successfully removed with combination of suboccipital craniotomy for fourth ventricle hematoma and intraventricular fibrinolysis for supratentorial hematoma.

The brainstem in multiple sclerosis: MR identification of tracts and nuclei damage

Objective

To evaluate the 3D Fast Gray Acquisition T1 Inversion Recovery (FGATIR) sequence for MRI identification of brainstem tracts and nuclei damage in multiple sclerosis (MS) patients.

Methods

From april to december 2020, 10 healthy volunteers and 50 patients with remitted-relapsing MS (58% female, mean age 36) underwent MR imaging in the Neuro-imaging department of the C.H.N.O. des Quinze-Vingts, Paris, France. MRI was achieved on a 3 T system (MAGNETOM Skyra) using a 64-channel coil. 3D FGATIR sequence was first performed on healthy volunteers to classify macroscopically identifiable brainstem structures. Then, FGATIR was assessed in MS patients to locate brainstem lesions detected with Proton Density/T2w (PD/T2w) sequence.

Results

In healthy volunteers, FGATIR allowed a precise visualization of tracts and nuclei according to their myelin density. Including FGATIR in MR follow-up of MS patients helped to identify structures frequently involved in the inflammatory process. Most damaged tracts were the superior cerebellar peduncle and the transverse fibers of the pons. Most frequently affected nuclei were the vestibular nuclei, the trigeminal tract, the facial nerve and the solitary tract.

Conclusion

Combination of FGATIR and PD/T2w sequences opened prospects to define MS elective injury in brainstem tracts and nuclei, with particular lesion features suggesting variations of the inflammatory process within brainstem structures. In a further study, hypersignal quantification and microstructure information should be evaluated using relaxometry and diffusion tractography. Technical improvements would bring novel parameters to train an artificial neural network for accurate automated labeling of MS lesions within the brainstem.

Posterior Fossa Teratomas in Adults : A Systematic Review

Objective

The occurrence of posterior fossa teratomas in adulthood is extremely rare. In this study, we aimed to report our experience with two cases of posterior fossa mature teratoma in adults who underwent surgical resection. We also performed a systematic review of published papers available to date.

Methods

We retrospectively reviewed the electronic medical records of patients who had onset of posterior fossa teratomas in adulthood at our institute between 1995 and 2020. We evaluated the clinical, radiographic, and pathological features of mature teratomas at the posterior fossa in adulthood. Furthermore, we searched the PubMed, EMBASE, and Web of Science database and reviewed published articles.

Results

We found 507 articles on database review; of them, 102 were duplicates and 389 were excluded based on the inclusion criteria. Finally, 16 cases of posterior fossa from the web search and related articles. Subsequently, we added two cases that underwent surgery at our institute. We analyzed a total of 18 cases of mature teratomas. Headache was the most common (55.6%) symptom. The teratomas showed heterogeneous signals on magnetic resonance imaging. Thirteen patients (72.2%) had lesion at midline, five patients (27.8%) had calcification. Surgical resection was performed in all patients. No studies reported recurrence after resection.

Conclusion

The occurrence of posterior fossa teratomas in adulthood is difficult to diagnose at the initial stage. Radiographic diagnosis alone can lead to misdiagnosis. Pathological confirmation is essential. Surgical resection is a curative option for posterior fossa teratomas in adulthood.

Cervical vestibular-evoked myogenic potentials in patients with essential tremor

Although different neuroanatomical structures and pathways are emphasized as possible explanations for essential tremor (ET), there is still an ongoing debate. This study aimed to assess the role of brainstem and reflex pathways with cervical vestibular-evoked myogenic potentials (VEMP) in patients with ET. This prospective study included 34 patients with ET and 25 healthy controls. Cervical VEMP was performed in both groups and latencies, inter-peak latency intervals, peak-to-peak amplitudes and asymmetry ratios were recorded. There was statistically no significant difference between the groups in terms of age (38.9 ± 14.9 years vs. 38.9 ± 14.9 years, p = 0.673) and gender (female to male ratio: 14/11 vs. 20/14, p = 0.828). Right N1 latency and right N1-P1 interval were significantly longer in the patient group (p < 0.05). There was a significant positive correlation between the duration of disease and the right N1-P1 interval (p < 0.05). There was no significant difference between the patient and control groups in terms of bilateral P1 latency, left N1 latency, left N1-P1 interval, and bilateral N1 and P1 amplitudes (p˃0.05). Cervical VEMP may reveal the involvement of brainstem and associated reflex pathways in ET.

Stereotactic posterior midline approach under direct microscopic view for biopsy of medulla oblongata tumors: technical considerations

Background

Open and stereotactic transfrontal or transcerebellar approaches have been used to biopsy brainstem lesions.

Method

In this report, a stereotactic posterior and midline approach to the distal medulla oblongata under microscopic view is described. The potential advantages and limitations are discussed, especially bilateral damage of the X nerve nuclei.

Conclusion

This approach should be considered for biopsy of distal and posterior lesions. We strongly recommend the use of direct microscopic view to identify the medullary vessels, confirm the midline entry point, and avoid potential shift of the medulla. Further experience is needed to confirm safety and success rate of this approach.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04600-6) contains supplementary material, which is available to authorized users.

Case of simultaneous Chiari 1.5 malformation and syringobulbia

Chiari 1.5 malformation (C1.5) is a rare condition characterized by caudal descent of the brain stem, together with descent of the cerebellar tonsils characteristic of Chiari I malformation (CIM). Syringobulbia (SB) is rarely associated with CIM and to date has not been reported in a patient with C1.5. An adolescent female presented with Valsalva-induced headaches and a left abducens nerve palsy. Imaging revealed C1.5 and a huge syringomyelia extending cranially into the herniated medulla oblongata as syringobulbia. Simultaneous cases of C1.5 and syringomyelia (SM) have been described, but, to our knowledge, this is the first reported case of simultaneous C1.5 and SB. As SB can have life altering consequences, the clinician should keep this possibility in their differential diagnosis.

Orexin-A directly depolarizes dorsomedial hypothalamic neurons, including those innervating the rostral ventrolateral medulla

The dorsomedial hypothalamus (DMH) receives dense orexinergic innervation. Intra-DMH application of orexins increases arterial pressure and heart rate in rats. We studied the effects of orexin-A on DMH neurons, including those innervating the medullary cardiovascular center, the rostral ventrolateral medulla (RVLM), by using whole-cell recordings in brain slices. In the presence of tetrodotoxin, orexin-A (30-1000 nM) depolarized 56% of DMH neurons (EC50 82.4 ± 4.4 nM). Under voltage-clamp recording, orexin-A (300 nM) induced three types of responses characterized by different current-voltage relationships, namely unchanged, increased, and decreased slope conductance in 68%, 14%, and 18% of orexin-A-responsive neurons, respectively. The reversal potential of the decreased-conductance response was near the equilibrium potential of K+ and became more positive in a high-K+ solution, suggesting that K+ conductance blockade is the underlying mechanism. In a low-Na+ solution, unchanged-, increased-, and decreased-conductance responses were observed in 56%, 11%, and 33% of orexin-A-responsive neurons, respectively, implying that a non-selective cation current (NSCC) underlies orexin-A-induced responses in a small population of DMH neurons. KBR-7943 (70 μM), an inhibitor of Na+-Ca2+ exchanger (NCX), suppressed orexin-A-induced depolarization in 7 of 10 neurons. In the presence of KBR-7943, the majority of orexin-A-responsive neurons exhibited decreased-conductance responses. These findings suggest that NCX activation may underlie orexin-A-induced depolarization in the majority of orexin-responsive DMH neurons. Of 19 RVLM-projecting DMH neurons identified by retrograde labeling, 17 (90%) were orexin-A responsive. In conclusion, orexin-A directly excited over half of DMH neurons, including those innervating the RVLM, through decreasing K+ conductance, activating NCX, and/or increasing NSCC.

Neurologic Manifestations of COVID-19

Neurological manifestations of novel coronavirus disease (COVID-19) are reported to occur in as much as 37% of the affected patients. These manifestations range from headache and dizziness to altered mental status and consciousness, anosmia, ageusia, sensory disturbances, and stroke. The mechanisms by which the neurological symptoms arise are not yet determined but may either proceed as an indirect consequence of systemic hyperinflammation or result from the direct invasion of the virus to neural and glial cells. The neural invasion can explain both the retrograde pathway of encephalitis and the early manifestation of anosmia by invading the olfactory bulb. Moreover, in the case of attacking the brain stem, it may take part in the early apnea manifestation reported by patients. Additionally, neurotropism of the virus could be the cause of acute hemorrhagic encephalitis. Hyperinflammation can have acute and prolonged effects in the nervous system, such as acute demyelination and predisposition to multiple sclerosis. Moreover, the pro-inflammatory state contributes to hypercoagulation, which in turn could result in cerebrovascular injuries in COVID-19 patients. This chapter would discuss that the neurologic manifestations of the COVID-19 are to be looked at as a multifactorial entangled phenomenon.

Sympathetic hyperactivity, hypertension, and tachycardia induced by stimulation of the ponto-medullary junction in humans

OBJECTIVE

The purpose of this study is to investigate changes in autonomic activities and systemic circulation generated by surgical manipulation or electrical stimulation to the human brain stem.

METHODS

We constructed a system that simultaneously recorded microsurgical field videos and heart rate variability (HRV) that represent autonomic activities. In 20 brain stem surgeries recorded, HRV features and sites of surgical manipulation were analyzed in 19 hypertensive epochs, defined as the periods with transient increases in the blood pressure. We analyzed the period during electrical stimulation to the ponto-medullary junction, performed for the purpose of monitoring a cranial nerve function.

RESULTS

In the hypertensive epoch, HRV analysis showed that sympathetic activity predominated over the parasympathetic activity. The hypertensive epoch was more associated with surgical manipulation of the area in the caudal pons or the rostral medulla oblongata compared to controls. During the period of electrical stimulation, there were significant increases in blood pressures and heart rates, accompanied by sympathetic overdrive.

CONCLUSIONS

Our results provide physiological evidence that there is an important autonomic center located adjacent to the ponto-medullary junction.

SIGNIFICANCE

A large study would reveal a candidate target of neuromodulation for disorders with autonomic imbalances such as drug-resistant hypertension.

Children with developmental language disorder: a frequency following response in the noise study

Introduction

Children with developmental language disorder have been reported to have poor temporal auditory processing. This study aimed to examine the frequency following response.

Objective

This work aimed to investigate speech processing in quiet and in noise.

Methods

Two groups of children were included in this work: the control group (15 children with normal language development) and the study group (25 children diagnosed with developmental language disorder). All children were submitted to intelligence scale, language assessment, full audiological evaluation, and frequency following response in quiet and noise (+5QNR and +10QNR).

Results

Results showed no statically significant difference between both groups as regards IQ or PTA. In the study group, the advanced analysis of frequency following response showed reduced F0 and F2 amplitudes. Results also showed that noise has an impact on both the transient and sustained components of the frequency following response in the same group.

Conclusion

Children with developmental language disorder have difficulty in speech processing especially in the presence of background noise. Frequency following response is an efficient procedure that can be used to address speech processing problems in children with developmental language disorder.

Vasopressin and oxytocin beyond the pituitary in the human brain

Vasopressin and oxytocin are primarily synthesized in the magnocellular supraoptic and paraventricular nuclei of the hypothalamus and transported to the posterior pituitary. In the human, an extensive accessory magnocellular neuroendocrine system is present with contact to the posterior pituitary and blood vessels in the hypothalamus itself. Vasopressin and oxytocin are involved in social and behavioral functions. However, only few neocortical areas are targeted by vasopressinergic and oxytocinergic nerve fibers, which mostly project to limbic areas in the forebrain, where also their receptors are located. Vasopressinergic/oxytocinergic perikarya in the forebrain project to the brain stem and spinal cord targeting nuclei and areas involved in autonomic functions. Parvocellular neurons containing vasopressin are located in the suprachiasmatic nucleus and synchronize the activity of the pacemaker in this nucleus. From the suprachiasmatic nucleus fibers project to the parvocellular part of the paraventricular nucleus, where preautonomic neurons project to the intermediolateral nucleus in the thoracic spinal cord, from where the superior cervical ganglion is reached whose noradrenergic fibers terminate in the pineal gland to stimulate melatonin secretion at night. The pineal gland is also innervated by vasopressin- and oxytocin-containing fibers reaching the gland via the "central innervation" in the pineal stalk, which might be involve in an annual regulation of melatonin secretion.

Imaging of congenital cranial dysinnervation disorders: What radiologist wants to know?

We aim to review the imaging features of congenital cranial dysinnervation disorders. Characteristic imaging findings can define subtypes of these disorders through assessment of cranial nerves, extraocular muscles, orbital, and brain abnormalities. Duane retraction syndrome shows absent or hypoplasic 6th cranial nerve and preserved extraocular muscles (EOM). Mobius syndrome shows absent 7th and 6th cranial nerves, absence of facial colliculus, flattening of the dorsal aspect of the pons, hypoplasia of the pons and medulla, and flattening of the 4th ventricular floor. Congenital fibrosis of the extraocular muscles reveals unilateral or bilateral hypoplasia or aplasia of the 3rd cranial nerve, atrophy of superior rectus and levator palpebrae superioris muscles, and atrophy of the brainstem and cerebellar hemispheres. Horizontal gaze palsy and progressive scoliosis show characteristic split pons sign, butterfly medulla, absent facial colliculi, and spinal scoliosis. HOXA1 Mutations show a bilateral absence of 6th cranial nerves with the underdeveloped inner ear. Pontine Cap Tegmental Dysplasia shows ventral pontine hypoplasia, dorsal tegmental projection into the 4th ventricle, and variable cranial nerve deficits.

Longitudinal [18F]FDG-PET/CT analysis of the glucose metabolism in ApoE-deficient mice

Background

Strong line of evidence suggests that the increased risk to develop AD may at least be partly mediated by cholesterol metabolism. A key regulator of cholesterol transport is the Apolipoprotein E4 (ApoE4), which plays a fundamental role in neuronal maintenance and repair. Impaired function of ApoE4 may contribute to altered cerebral metabolism leading to higher susceptibility to neurodegeneration.

Methods

To determine a possible link between ApoE function and alterations in AD in the brain of Apolipoprotein E-deficient mice (ApoE−/−) in a longitudinal manner metabolic and neurochemical parameters were analyzed. Cortical metabolism was measured by 2-deoxy-2-[¹⁸F]fluoroglucose ([¹⁸F]FDG)-PET/CT and proton magnetic resonance spectroscopy (¹H-MRS) served to record neurochemical status.

Results

By using [¹⁸F]FDG-PET/CT, we showed that brain metabolism declined significantly stronger with age in ApoE−/− versus wild type (wt) mice. This difference was particularly evident at the age of 41 weeks in almost each analyzed brain region. In contrast, the ¹H-MRS-measured N-acetylaspartate to creatine ratio, a marker of neuronal viability, did not decline with age and did not differ between ApoE−/− and wt mice.

Conclusion

In summary, this longitudinal in vivo study shows for the first time that ApoE−/− mice depict cerebral hypometabolism without neurochemical alterations.

Coronaviruses: a challenge of today and a call for extended human postmortem brain analyses

While there is abounding literature on virus-induced pathology in general and coronavirus in particular, recent evidence accumulates showing distinct and deleterious brain affection. As the respiratory tract connects to the brain without protection of the blood-brain barrier, SARS-CoV-2 might in the early invasive phase attack the cardiorespiratory centres located in the medulla/pons areas, giving rise to disturbances of respiration and cardiac problems. Furthermore, brainstem regions are at risk to lose their functional integrity. Therefore, long-term neurological as well as psychiatric symptomatology and eventual respective disorders cannot be excluded as evidenced from influenza-A triggered post-encephalitic Parkinsonism and HIV-1 triggered AIDS-dementia complex. From the available evidences for coronavirus-induced brain pathology, this review concludes a number of unmet needs for further research strategies like human postmortem brain analyses. SARS-CoV-2 mirroring experimental animal brain studies, characterization of time-dependent and region-dependent spreading behaviours of coronaviruses, enlightening of pathological mechanisms after coronavirus infection using long-term animal models and clinical observations of patients having had COVID-19 infection are calling to develop both protective strategies and drug discoveries to avoid early and late coronavirus-induced functional brain disturbances, symptoms and eventually disorders. To fight SARS-CoV-2, it is an urgent need to enforce clinical, molecular biological, neurochemical and genetic research including brain-related studies on a worldwide harmonized basis.

Hyperventilation Increases the Randomness of Ocular Palatal Tremor Waveforms

Hyperventilation changes the extracellular pH modulating many central pathologies, such as tremor. The questions that remain unanswered are the following: (1) Hyperventilation modulates which aspects of the oscillations? (2) Whether the effects of hyperventilation are instantaneous and the recovery is rapid and complete? Here we study the effects of hyperventilation on eye oscillations in the syndrome of oculopalatal tremor (OPT), a disease model affecting the inferior olive and cerebellar system. These regions are commonly involved in the pathogenesis of many movement disorders. The focus on the ocular motor system also allows access to the well-known physiology and precise measurement techniques. We found that hyperventilation causes modest but insignificant changes in the intensity of oscillation displacement (i.e., how large the eye excursions are) and velocity (i.e., how fast do the eyes move during oscillations). We found the robust increase in the randomness of the oscillatory waveform during hyperventilation and it instantaneously reverts to the baseline after hyperventilation. The subsequent analysis classified the oscillations according to their waveform shape and randomness into different clusters. The hyperventilation substantially changed the cluster type in 60% of the subjects, but it reverted to the pre-hyperventilation cluster at the conclusion of the hyperventilation. In summary, hyperventilation instantaneously affects the randomness of the oscillatory waveforms but there are less substantial effects on the intensity. The deficits reverse immediately at the end of the hyperventilation.

Gabapentin and memantine increases randomness of oscillatory waveform in ocular palatal tremor

Syndrome of oculopalatal tremor (OPT) causes pendular nystagmus of the eyes and its disabling consequence on the visual system. Classic pharmacotherapeutic studies revealed reduction in the eye velocity of the oscillatory waveforms. Subjective improvement in vision, however, remains out of proportionately low. Elegant models depicting quasi-sinusoidal coarse oscillations of the eyes highlighted two distinct oscillators; one at the inferior olive causing primary 2 Hz oscillations, while the second, independent oscillator, at the cerebellum adding the randomness to the waveform. Here we examined whether pharmacotherapy affects the randomness of the oscillatory waveform. Horizontal, vertical, and torsional angular eye positions were measured independently from both eyes as six subjects with OPT directed gaze toward a straight-ahead target. The measurements were performed before administration of alpha-2-delta calcium channel blocker (gabapentin) or NMDA receptor antagonist (memantine) and after the subjects were treated with each of these drugs for at least 8 days. Amplitude and velocity of eye oscillations were reduced by gabapentin and memantine, but there was an increase in the waveform randomness. We found that the increase in randomness was proportionate to the amount of reduction in the waveform velocity or amplitude. Hierarchical clustering revealed distinct patterns of oscillatory waveforms, with each subject belonging to a specific cluster group. The pharmacotherapy changed the waveform clustering pattern of the waveform in each subject. We conclude that in addition to incomplete resolution of the oscillation intensity, increased randomness could be one of the reasons why there is not enough clinical difference in the patients' visual quality.

Is there a relationship between the extent of tonsillar ectopia and the severity of the clinical Chiari syndrome?

BACKGROUND

Chiari 1 malformation is diagnosed if the cerebellar tonsils extend at least 5 mm below the opisthion-basion line.

OBJECTIVE

To examine the correlation of the extent of tonsillar ectopia with the prevalence and severity of the symptoms associated with the Chiari malformation.

METHODS

Patients (N = 428) were grouped according to the extent of tonsillar ectopia on the mid-sagittal MRI image (group 1, 0-< 3 mm; group 2, 3-5 mm; group 3, > 5 mm). Groups were compared regarding demographics, symptoms, neurological signs, pain score, and response to HADS and sf-36 questionnaires. Results were analyzed using one-way ANOVA, chi-square, and two sample Z test, and Student's t test for pairwise comparison, (statistical significance p < 0.05). A logistic regression analysis was performed to determine the relationship between tonsillar ectopia and the probability of a patient reporting any particular symptom.

RESULTS

There were 97,148 and 183 patients in groups 1, 2, and 3 respectively. Groups did not differ with regard to antecedent trauma or female preponderance. Patients in group 1 were more symptomatic than those in groups 2 and 3 with regard to some symptoms, (p = 0.04-p = 0.000). Regression analysis confirmed an inverse relationship between the extent of tonsillar ectopia and the likelihood of many symptoms. The pain score was greatest in group 1, (p = 0.006). Prevalence of objective signs of myelopathy did not differ between groups except for Hoffmann sign which was more prevalent in group 1, (p = 0.034). HADS and sf-36 scores did not differ between groups.

CONCLUSION

The severity of the symptoms associated with the Chiari malformation does not correlate directly with the extent of tonsillar ectopia. The extent of tonsillar ectopia should be re-evaluated as the threshold for diagnosis of Chiari 1 malformation.

The importance of optimal ROIs delineation for FBPA-PET before BNCT

One of the eligible criteria for patients to receive boron neutron capture therapy (BNCT) is based on the tumour-to-normal ratio (T/N) measured by FBPA-PET. However, there is no standard protocol for normal region-of-interested delineation. With comparison of contralateral cerebrum, our study revealed the consistency (p < 0.05) and high feasibility using the cerebellum as an alternative normal tissue baseline because of its homogeneous uptake. Following RECIST version 1.1, the standard-operating-procedure (SOP) for the BNCT fulfilled the expected tumour response and tumour shrinkage rate (p < 0.05). Our modified procedure can provide more precise information for BNCT within a reasonable time.

A Rare Case Report of Acute Necrotizing Encephalopathy of Childhood

OBJECTIVE

Acute necrotizing encephalopathy of childhood (ANEC) is a fast growing disease, accompanied by progressive encephalopathy. The aim of this study was to report a rare case of ANEC in a four-year-old boy with bilateral thalamic necrosis and non-fatal outcomes.

CASE REPORT

The patient was a four-year-old Iranian boy, without any history of health problems or hospitalization, except for jaundice and phototherapy in the neonatal period. He had no neurological signs or symptoms during admission, and he was admitted only with chief complaints of acute onset of fever, coryza, and icterus. In the neurological consultation, brain MRI was requested to analyze the possibility of brain damage. The results indicated the involvement of cerebellum, thalamus, and basal ganglia, which led to the diagnosis of ANEC.

CONCLUSION

Based on our findings, although ANEC is a rare disease, it should not be underestimated.

Physiological and pathophysiological evaluation of baroreflex functionality with concurrent diffusion tensor imaging of its neural circuit in the rat

Background

By measuring the prevalence of neuronal traffic between two brain structures based on the notion that diffusion of water molecules along the axon in parallel bundles will create prominent anisotropy in the direction of the passage of action potentials, diffusion tensor imaging (DTI) may be taken as an effective tool for functional investigations. Demonstration of complementary results obtained from synchronized DTI of the baroreflex neural circuit and physiological or pathophysiological evaluation of baroreflex functionality should validate this notion.

Methods

We implemented concurrent changes in neuronal traffic within the neural circuit of the baroreflex-mediated sympathetic vasomotor tone in the brain stem and alterations of its experimental surrogate under physiological and pathophysiological conditions. We further evaluated the functional and clinical implications of results obtained from this experimental paradigm in conjunction with baroreflex induction and a mevinphos intoxication model of brain stem death.

Results

We found that robust connectivity existed between the nucleus tractus solitarii and rostral ventrolateral medulla, the afferent and efferent nuclei of the baroreflex-mediated sympathetic vasomotor. Intriguingly, this connectivity was either reversibly disrupted or irreversibly severed to reflect alterations in baroreflex responses to physiological or pathophysiological challenges.

Conclusions

The capability to observe simultaneous and complementary changes in neuronal traffic within the neural circuit of the baroreflex-mediated sympathetic vasomotor tone and alterations of its experimental surrogate that bears technical, scientific and clinical implications sustains the notion that coupled with relevant physiological phenotypes, DTI can be an effective investigative tool for functional evaluations of brain stem activities.

Newborn Hearing Screening: Time to Act!

The present study was carried out with the aim of assessing the outcomes of otoacoustic hearing screening in newborns coupled with the three stage protocol. It was a hospital based observational study which was conducted over a time period of twelve months at a tertiary care institute to screen 2000 live neonates for congenital hearing impairment using OAE, followed up by tympanometry and BERA, if required. 2000 neonates were screened for hearing impairment. 406 were in high risk group and the rest in non-high risk group. Seven neonates had absent V wave on BERA. Five of them were high risk babies and the rest two were non-high risk ones. In order to ensure that early detection and effective intervention are possible for all neonates with hearing impairment, UNHS should be performed. Three stage UNHS protocol using OAE and BERA showed that the implementation of UNHS for congenital childhood hearing loss for all neonates would be beneficial.

Limited positive predictive value of diffusion tensor tractography in determining clinically relevant white matter damage in brain stem cavernous malformations: A retrospective study in a single center surgical cohort

PURPOSE

Diffusion tensor tractography (DTT) might reflect the postoperative clinical outcome of the patients with brain stem (BS) tumors correlating well with the neurological symptoms, but cavernous malformation (CM) is a hemorrhagic tumor prone to artifacts that may limit DTT. We set out to determine the correlation of DTT findings with the neurological examination before and after surgical resection in patients with BSCMs.

MATERIALS AND METHODS

DTT findings were evaluated bilaterally for fiber tract displacement or deviation, deformation and interruption in every patient before and after the surgery. Neurological examination was performed at admission, discharge and outpatient follow-up visit. The sensitivity, specificity, positive and negative predictive values of DTT were calculated both pre- and post-operatively.

RESULTS

There were 25 patients (9 men 16 women) with a mean age of 39.5±13.9 years. The mean size of the CMs was 6909±8374mm³ (range: 180-38,220mm³) The mean follow-up time was 42.7±23.2 months (range: 8 to 112 months). Preoperatively, the sensitivity, specificity, positive and negative predictive values of DTT for corticospinal tracts (CST) and medial lemnisci (ML) were 100%, 60%, 38.4%, 100% and 87.5%, 11.7%, 31.8%, 66.6%, respectively. Postoperatively, the sensitivity, specificity, positive and negative predictive values of DTT for CSTs and ML were 100%, 64.7%, 40%, 100% and 100%, 0%, 33.3%, 66.6%, respectively.

CONCLUSION

Positive findings on DTT such as fiber tract deviation, deformation, disruption or interruption should be taken cautiously before drawing conclusions of a clinically relevant damage of white matter tracts.

[Clinical features of 19 children with Bickerstaff brainstem encephalitis]

Objective: To summarize the clinical features of Bickerstaff brainstem encephalitis (BBE) in children. Methods: In this retrospective study, data of 19 patients with BBE (11 males and 8 females) were collected from Department of Neurology, Beijing Children's Hospital from October 2015 to January 2018. The clinical features, treatment and prognosis were analyzed. Results: The onset age of BBE ranged from 1 year and 8 months to 12 years and 11 months. There were 18 cases with preceding infection. The most common infection was upper respiratory tract infection (9 cases), followed by simple fever (5 cases). The most common initial neurological symptoms were lethargy or disturbance of consciousness (8 cases), followed by limb weakness (5 cases). There were 6 cases of simple BBE and 13 cases of BBE overlapping Guillain-Barré syndrome (GBS). Besides the characteristic triad of altered mental status, ataxia, and ophthalmoplegia, there were other symptoms including convulsion (5 cases), diplopia (3 cases), nystagmus (7 cases), facial muscular weakness (7 cases),bulbar palsy (13 cases) and autonomic nerve symptoms (9 cases). Hypo or areflexia was seen in 16 cases. Positive Babinski's signs were seen in 8 cases. Hyponatremia was present in 10 cases in whom 4 showed severe hyponatremia. Albumin-cytological dissociation of cerebrospinal fluid was seen in 10 cases. The autoimmune antibodies were examined in all 19 patients. Anti-ganglioside antibodies including anti-GM1 IgG antibody was positive in 2 patients and one of whom was also found with positive anti-GD1b IgG antibody. Anti-GQ1b IgG antibody was present in 2 patients. Electromyography was performed in 14 cases and 8 cases, who were all BBE overlapping GBS, showed neurological damage. A total of 16 cases were monitored by video electroencephalography and 8 cases showed slow waves of background. In addition to, interictal focal discharge was detected in 2 cases. T2 fluid-attenuated inversion recovery (FLAIR) sequence abnormal signals were detected in 3 of 18 cases performed brain magnetic resonance imaging (MRI), and lesions involved with brainstem, basal ganglia, thalamus, cerebellum, corpus callosum and cerebral cortex. Lesions involved cervical and thoracic spinal cord were found in 1 out of 11 cases for whom spinal cord MRI was performed. All of the 4 cases who underwent enhanced MRI of spinal had partial nerve roots enhancement. All of the 19 patients received 1 to 2 courses of intravenous immunoglobulin therapy, and 2 cases also received plasma exchange. Fifteen cases received steroid therapy. The following-up period ranged from 3 months to 2.5 years. Two cases were lost to follow-up. Twelve cases achieved a full recovery within 3 months. Three cases recovered within 6 months. One case still had slight limb weakness and ataxia after 1 year and 8 months of follow-up, and another case had left autonomic nerve symptoms in the follow-up of 2 years and 3 months. Both of them were BBE overlapping GBS. Conclusions: Children's BBE is similar to that in adults, and is frequently found overlapped with GBS. Furthermore, it is sometimes accompanied by central nervous system demyelination disease. The antiganglioside antibodies are not often detectable. Immunoglobulin therapy could usually achieve good response. The prognosis of simple BBE is good in most situations. For BBE overlapping GBS, the more severe the limb weakness during the peak of disease is, the slower the recovery would be.

The differences in brain stem transcriptional profiling in hypertensive ISIAH and normotensive WAG rats

BACKGROUND

The development of essential hypertension is associated with a wide range of mechanisms. The brain stem neurons are essential for the homeostatic regulation of arterial pressure as they control baroreflex and sympathetic nerve activity. The ISIAH (Inherited Stress Induced Arterial Hypertension) rats reproduce the human stress-sensitive hypertensive disease with predominant activation of the neuroendocrine hypothalamic-pituitary-adrenal and sympathetic adrenal axes. RNA-Seq analysis of the brain stems from the hypertensive ISIAH and normotensive control WAG (Wistar Albino Glaxo) rats was performed to identify the differentially expressed genes (DEGs) and the main central mechanisms (biological processes and metabolic pathways) contributing to the hypertensive state in the ISIAH rats.

RESULTS

The study revealed 224 DEGs. Their annotation in databases showed that 22 of them were associated with hypertension and blood pressure (BP) regulation, and 61 DEGs were associated with central nervous system diseases. In accordance with the functional annotation of DEGs, the key role of hormonal metabolic processes and, in particular, the enhanced biosynthesis of aldosterone in the brain stem of ISIAH rats was proposed. Multiple DEGs associated with several Gene Ontology (GO) terms essentially related to modulation of BP were identified. Abundant groups of DEGs were related to GO terms associated with responses to different stimuli including response to organic (hormonal) substance, to external stimulus, and to stress. Several DEGs making the most contribution to the inter-strain differences were detected including the Ephx2, which was earlier defined as a major candidate gene in the studies of transcriptional profiles in different tissues/organs (hypothalamus, adrenal gland and kidney) of ISIAH rats.

CONCLUSIONS

The results of the study showed that inter-strain differences in ISIAH and WAG brain stem functioning might be a result of the imbalance in processes leading to the pathology development and those, exerting the compensatory effects. The data obtained in this study are useful for a better understanding of the genetic mechanisms underlying the complexity of the brain stem processes in ISIAH rats, which are a model of stress-sensitive form of hypertension.

Respiratory frequency plasticity during development

Respiratory frequency plasticity is a long-lasting increase in breathing frequency due to a perturbation. Mechanisms underlying respiratory frequency are poorly understood, and there is little evidence of frequency plasticity in neonates. This hybrid review/research article discusses available literature regarding frequency plasticity and highlights potential research opportunities. Also, we include data demonstrating a model of frequency plasticity using isolated neonatal rat brainstem-spinal cord preparations. Specifically, substance P (SubP) application induced a long-lasting (>60 min) increase in spontaneous respiratory motor burst frequency, particularly in brainstem-spinal cords with the pons attached; there were no male/female differences. SubP-induced frequency plasticity is dependent on the application pattern, such that intermittent (rather than sustained) SubP applications induce more frequency plasticity. SubP-induced frequency plasticity was blocked by a neurokinin-1 receptor antagonist. Thus, the newborn rat respiratory control system has the capacity to express frequency plasticity. Identifying mechanisms that induce frequency plasticity may lead to novel methods to safely treat breathing disorders in premature and newborn infants.

Acupuncture activates a direct pathway from the nucleus tractus solitarii to the rostral ventrolateral medulla

Our previous studies have shown that electroacupuncture (EA) at the Jianshi-Neiguan acupoints (P5-6, overlying the median nerve) attenuates sympathoexcitatory responses through its influence on neuronal activity in the rostral ventrolateral medulla (rVLM). The nucleus tractus solitarii (NTS) receives input from somatic nerve stimulation. Connections between the NTS and the rVLM during EA stimulation have not been investigated and thus were the focus of the present study. Seven to ten days after unilateral microinjection of a rhodamine-conjugated microsphere retrograde tracer (100 nl) into the rVLM, rats were subjected to EA or sham-EA without electrical stimulation. EA was performed for 30 min at the P5-6 acupoints bilaterally. Perikarya containing the microsphere tracer were found in the NTS of both groups. Compared to controls (needle placement without electrical stimulation, n = 7), c-Fos immunoreactivity and neurons double-labeled with c-Fos, an immediate early gene, and the tracer were significantly increased in the NTS of EA-treated rats (all P < 0.05; n = 8), particularly, in the medial and lateral subdivisions of NTS at subpostremal and obex levels. These results suggest that EA at the P5-6 acupoints activates NTS neurons. Furthermore, EA-activated NTS neurons directly project to the rVLM and likely influence the rVLM activity.

Reduced axial diffusivity and increased mode and T2 signals in cerebral white matter of chronic obstructive pulmonary disease using tract-based spatial statistics

PURPOSE

Chronic obstructive pulmonary disease (COPD) is considered to be a multi-systemic disease involving pathological changes in the brain. This study investigated how diffusion tensor imaging (DTI) parameters in patients with non-hypoxemic COPD differ from those in controls. Moreover, we tried to examine whether the mode of anisotropy (MO) reflects early changes in white matter (WM) integrity in COPD.

METHODS

DT images were obtained from 13 male COPD patients and 13 age- and sex-matched healthy controls. Raw DT images were processed using an automated tract-based spatial statistics (TBSS) pipeline. DTI scalars of fractional anisotropy (FA); axial, radial, and mean diffusivities (AD, RD, and MD, respectively); MO; and raw T2 signal (S0) were statistically compared between COPD patients and controls. TBSS methods were used for analysis.

RESULTS

In patients with COPD, decreased AD was observed in the temporal stem (TS), corticospinal tract (CST), thalamus, subiculum, crus cerebri, and midbrain. Increased MO values were found in the corpus callosum, CST, internal capsule, cerebellar peduncle (CP), and medial lemniscus (ML). Additionally, increased S0 was found in the TS, CP, pons, and cerebellar tonsil (threshold-free cluster enhancement to a family-wise error rate of p < 0.05).

CONCLUSION

The results revealed decreased AD and increased MO scalars in COPD patients compared with the controls, although there were no differences in FA, RD, and MD scalars. Decreased AD and increased MO scalars may reflect early changes in WM integrity in COPD patients.

Brainstem gliomas in pregnancy: a systematic review†

Introduction: Although brainstem gliomas are a rare group of neoplasias, when they affect pregnant women, there can be challenges with diagnosis and management. This study describes a case of brainstem glioma diagnosed in pregnancy and systematically reviews the literature on brainstem gliomas in pregnancy to provide guidance for management.Material and methods: We searched five databases from inception until October 2016 using subject headings and keywords related to pregnancy and brainstem glioma, and included original research articles that described pregnancy outcomes in women with brainstem glioma. Data extraction and quality assessment using the Joanna Briggs Institute Critical Appraisal Checklist for case reports were performed in duplicate. Outcomes were reported as proportions. The study protocol was registered with the Prospero International Prospective Register of Systematic Reviews (CRD42017060196).Results: We screened 2737 titles and abstracts, and 89 full-texts. Twelve articles describing 17 pregnancies in 16 women were included in the analysis. The median gestational age at presentation was 23 weeks. All but one case presented with neurologic deficit. Magnetic resonance (MRI) imaging conclusively diagnosed all cases. Surgical tumor resection (n = 4) and radiation therapy (n = 3) were successfully undertaken during pregnancy. There were no reported sequelae of maternal oncological management on neonatal wellbeing. Maternal mortality was high (8/16, 50%) both during (n = 5) and within 4 weeks (n = 3) of pregnancy. Pregnancy losses included one pregnancy termination and four miscarriages (associated with maternal mortality). Of the 12 live-born babies, five were premature. Two of these were the result of spontaneous preterm labor and three were delivered prematurely to facilitate glioma management. There was one case of fetal growth restriction.Conclusions: Although the symptoms of brainstem gliomas often mimic those commonly encountered in pregnancy, neurologic deficits warrant urgent investigation. MRI is the diagnostic modality of choice in pregnancy. Brainstem gliomas are associated with high maternal mortality and appropriate management, including surgical tumor resection and radiation therapy, should not be delayed on account of pregnancy. Pregnancy outcomes are favorable although there is a risk of preterm birth.Key messageBrainstem gliomas are associated with high maternal mortality and timely diagnosis using magnetic resonance imaging and treatment including surgical resection and radiation therapy should not be delayed during pregnancy. Pregnancy outcomes are generally favorable except for risk of preterm birth.

[Establishment and clinical significance of vestibular-evoked myogenic potential detection method]

Objective: To study the integrity of vestibular brain stem pathway and explore the diagnostic and clinical value of vestibular-evoked myogenic potentials (VEMPs) in central nervous system diseases through the establishment of detection method of VEMPs. Method: Seventy-two normal volunteers (included between April 2016 and July 2017) were divided into 6 groups according to different ages.All subjects were tested with short acoustic stimulation.The superior oblique, masseter and sternocleidomastoid muscles were recorded respectively, and the stable waveform was obtained: (1)the Opposite ocular potential (o- VEMP) N1 and P1; (2)the bilateral masseter potential (m-VEMP) P11; (3)the same side neck potential (c-VEMP) P13 and N23.The three detection methods were used to measure the latency period, the amplitude of the peak value, the ratio of the amplitude before and after the stimulus, and the logarithm value of the ratio. Results: The mean values of latency period of N1, P11 and P13 were 10.9-12.0 ms, 11.3-13.6 ms, 13.2-14.6 ms, among which the occurrence rates of o-vemp, m-vemp and c-vemp were respectively 97.2%, 98.5% and 95.4%.With the increase of age, the latency period of each wave was observed to be prolonged, with significant difference (P<0.05), while no significant difference in the gender and side of each wave (P> 0.05). Conclusions: VEMPs are noninvasive measurement technology, stable and reliable, and can objectively evaluate the integrity of the vestibular brainstem pathway from three segment. This technology has broad application prospects in the central nervous system diseases, especially in neurodegenerative disease.

Vertical bundles of the white matter fibers in the pons revisited: preliminary study utilizing the Klingler technique

The inner structure of the pons contains several layers of transverse and vertical fibers and many nuclei. The vertical bundles are described as fibers of the corticospinal tract, corticonuclear tract, frontopontine tract and parieto-temporopontine tract organized in three layers. The aim of this study was to investigate the structure of the vertical bundles in the ventral pons using the modified Klingler method. Ten brain stem specimens were investigated. Specimens were fixed in 10% formalin, frozen for 24 h to separate nerve fibers by ice crystals, and then unfrozen again in 10% formalin solution. Afterwards, the specimens were dissected using a sharpened spatula. Results point to the existence of three main layers of vertical bundles and a small, constant, and superficial fourth fascicle that is yet to be described in the literature. We propose the name fasciculus longitudinalis superficialis (superficial longitudinal fascicle) for this group of vertical fibers of the pons.

Paradoxical Sleep Deprivation Aggravates and Prolongs Incision-Induced Pain Hypersensitivity via BDNF Signaling-Mediated Descending Facilitation in Rats

The mechanisms underlying the pronociceptive effect of paradoxical sleep deprivation (PSD) are not fully established. The modulation of BDNF signaling-mediated descending facilitation from the rostral ventromedial medulla (RVM) of brain stem has been demonstrated in persistent pain models of inflammatory pain, but not in incisional pain model. Recent study has shown that PSD increases the expression of brain-derived neurotrophic factor (BDNF) in the brainstem structure. Therefore, in the current study, we asked whether the BDNF signaling-mediated descending facilitation was involved in the PSD-induced pronociceptive effect on incisional pain and delay the recovery period of postoperative pain in rats. Our results found that a preoperative 24 h PSD significantly aggravated the pain hypersensitivity after incision and prolonged the duration of postoperative pain. The lesions of ipsilateral dorsolateral funiculus partly reversed the PSD-induced pronociceptive effect on incisional pain. Interestingly, the 24 h PSD, but not incision significantly enhanced the levels of BDNF protein expression in the RVM areas of rats. Furthermore, at 1 day or 4 days after incision, intra-RVM microinjection of a BDNF antibody partly reversed the PSD-induced pronociceptive effects in incisional rats, while it did not change the cumulative pain scores and paw withdrawal thresholds in rats receiving only plantar incision. These findings suggest that the preoperative PSD may aggravate and prolong the incision-induced pain hypersensitivity via BDNF signaling-mediated descending facilitation.

Botulinum Toxin Type A: Assessing The Effects on The Brain Stem

BACKGROUND

In this study, our aim is to investigate the possible effects of Botulinum toxin type A administrations in the early and late periods on the brain stem.

METHODS

Eighteen white New Zealand rabbits were used in this study with the subjects being divided into three groups. Group I received 0.05 mL sterile saline to the left anterior auricular muscles. Group II and III were injected with Botulinum toxin type A (Botox, Allergan) to the left anterior auricular muscles. Group II was sacrificed 5 days after application and Group III was sacrificed 12 weeks after application; brain stem tissues were then taken. The samples were examined with Caspase 3, 8, and 9 immunohistochemical stainings.

RESULTS

In the control group with Caspase-3 immune staining, moderate-to-strong immune reactivity was seen in a small number of neurons. In the Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers when compared with the Caspase-3 immune reactive neurons. In the early and late period, groups with Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers and in the wider area when compared with the Caspase-3 immune reactive neurons. No significant differences were recognized in the Caspase immune stainings between the early and late period groups. The results were statistically supported.

CONCLUSION

It was concluded that Botulinum toxin type A application did not trigger apoptosis in stem cell tissues.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Chronic oxycodone induces axonal degeneration in rat brain

BACKGROUND

Chronic opioid therapy for non-malignant pain conditions has significantly increased over the last 15 years. Recently, the correlation between opioid analgesics and alternations in brain structure, such as leukoencephalopathy, axon demyelination, and white matter lesions, has been demonstrated in patients with a history of long-term use of prescription opioids. The exact mechanisms underlying the neurotoxic effect of opioids on the central nervous system are still not fully understood. We investigated the effect of chronic opioids using an animal model in which female rats were orally gavaged with 15 mg/kg of oxycodone every 24 h for 30 days. In addition we tested oxycodone, morphine and DAMGO in breast adenocarcinoma MCF7 cells, which are known to express the μ-opioid receptor.

RESULTS

We observed several changes in the white matter of animals treated with oxycodone: deformation of axonal tracks, reduction in size of axonal fascicles, loss of myelin basic protein and accumulation of amyloid precursor protein beta (β-APP), suggesting axonal damages by chronic oxycodone. Moreover, we demonstrated activation of pro-apoptotic machinery amid suppression of anti-apoptotic signaling in axonal tracks that correlated with activation of biomarkers of the integrated stress response (ISR) in these structures after oxycodone exposure. Using MCF7 cells, we observed induction of the ISR and pro-apoptotic signaling after opioid treatment. We showed that the ISR inhibitor, ISRIB, suppresses opioid-induced Bax and CHOP expression in MCF7 cells.

CONCLUSIONS

Altogether, our data suggest that chronic opioid administration may cause neuronal degeneration by activation of the integrated stress response leading to induction of apoptotic signaling in neurons and also by promoting demyelination in CNS.

Central-Variant Posterior Reversible Encephalopathy Syndrome with Albuminocytologic Dissociation

Posterior reversible encephalopathy syndrome (PRES) is a disorder of reversible vasogenic brain edema which mainly involves the parieto-occipital lobes in various clinical settings. The main mechanism is known to be cerebral autoregulation failure and endothelial dysfunction leading to the disruption of the blood-brain barrier. We report the case of a 47-year-old woman with PRES which involved the brain stem and thalami, sparing the cerebral hemispheres. She was admitted to the emergency room because of acute-onset confusion. Her initial blood pressure was 270/220 mm Hg. Routine blood lab tests showed pleocytosis, hyperglycemia, and azotemia. Brain magnetic resonance imaging (MRI) showed a lesion of vasogenic edema involving nearly the whole area of pons, the left side of the midbrain, and the bilateral medial thalami. Cerebrospinal fluid (CSF) examination revealed an increased level of protein with normal white blood cell count. With conservative care, the patient markedly recovered 3 days after symptom onset, and a follow-up MRI confirmed complete resolution of the vasogenic edema. This case suggests that PRES can rarely involve the "central zone" only, sparing the cerebral hemispheres, which may be confused with other neurological diseases. Besides, the CSF albuminocytologic dissociation may suggest the disruption of the blood-brain barrier in patients with PRES.

IDH1 Mutation in Brain Stem Glioma: Case Report and Review of Literature

The role of isocitrate dehydrogenase 1 (IDH1) mutation in brain stem glioma is not clear. To the best of our knowledge, six cases of brain stem gliomas carrying IDH1/2 mutations are currently reported in the literature. One case of diffuse brain stem glioma with IDH1 mutation, which was followed for 2 years, is presented and compared with IDH1 negative tumors. A 22-year-old lady was referred with diplopia and left arm palsy. Neuroimaging detected a nonenhancing, nonhomogeneous diffuse infiltrating brain stem tumor extending from pons to medulla. Microsurgical debulking was performed. Microscopic evaluation of the tissue specimen and immunohistochemistry revealed an astrocytoma WHO Grade II with proliferation rate of 3% and glial fibrillary acidic protein (GFAP)-positive tumor cells. Interestingly, the tumor cells expressed mutated IDH1 R132H protein. The patient underwent adjuvant radiation and chemotherapy. The primary and 2 years' clinical/radiological characteristics did not indicate any significant difference from other cases without IDH1 mutation. the prognostic value of IDH1/2 mutation in brain stem glioma is unclear. Brain stem biopsies may allow determination of a tissue-based tumor diagnosis for further investigations.

The Anorexigenic Neural Pathways of Oxytocin and Their Clinical Implication

Oxytocin was discovered in 1906 as a peptide that promotes delivery and milk ejection; however, its additional physiological functions were determined 100 years later. Many recent articles have reported newly discovered effects of oxytocin on social communication, bonding, reward-related behavior, adipose tissue, and muscle and food intake regulation. Because oxytocin neurons project to various regions in the brain that contribute to both feeding reward (hedonic feeding) and the regulation of energy balance (homeostatic feeding), the mechanisms of oxytocin on food intake regulation are complicated and largely unknown. Oxytocin neurons in the paraventricular nucleus (PVN) receive neural projections from the arcuate nucleus (ARC), which is an important center for feeding regulation. On the other hand, these neurons in the PVN and supraoptic nucleus project to the ARC. PVN oxytocin neurons also project to the brain stem and the reward-related limbic system. In addition to this, oxytocin induces lipolysis and decreases fat mass. However, these effects in feeding and adipose tissue are known to be dependent on body weight (BW). Oxytocin treatment is more effective in food intake regulation and fat mass decline for individuals with leptin resistance and higher BW, but is known to be less effective in individuals with normal BW. In this review, we present in detail the recent findings on the physiological role of oxytocin in feeding regulation and the anorexigenic neural pathway of oxytocin neurons, as well as the advantage of oxytocin usage for anti-obesity treatment.

[Calculating the Hausdorff distance based on the scripting in RayStation treatment planning system]

Objective: To calculate out the Hausdorff distance based on the scripting in RayStation treatment planning system, which was then applied in measuring the deformation error of brain stem during image automatic registration between CT and MR. Methods: Scripting was edited in RayStation system (version 4.7) by using IronPython. The set of point coordinates on the contour of any two region of interest (ROI) had been found firstly, then the Hausdorff distance between the two point sets was calculated out. A graphical user interface (GUI) was designed by using XAML to acquire the visualized output of Hausdorff distance. GUI appeared when the script was run, where two ROIs was selected, then the corresponding Hausdorff distance and the running time were displayed by pressing the "Calculate" button. Results: The mean Hausdorff distance of brain stem in 20 patients with head and neck neoplasms was 1.20 cm while the mean elapsed time was 11.01s. Conclusions: Hausdorff distance of any two ROIs can be calculated out by using the developed method. GUI is designed to realize the visual interaction with RayStation system. Therefore, the RayStation system satisfies the demands of Hausdorff distance calculation in both clinical and research work.