镇静清醒麻醉下手术切除语言功能区脑胶质瘤

目的探讨清醒麻醉下手术切除语言功能区胶质瘤并保全其语言功能的可行性及其治疗效果。方法选择位于语言功能区的脑胶质瘤患者10例,实施头皮神经干阻滞麻醉后全程清醒开颅手术,切除肿瘤中维持患者进行出声连续计数的语言功能监测,使尽可能全切肉眼可见肿瘤而保存功能脑区。结果清醒开颅手术全过程中麻醉满意,手术中患者能很好地完成语言监测配合,其中8例患者实现肿瘤的肉眼全切;术后未出现手术相关性语言障碍并发症;随访6～20个月,无肿瘤复发病例。结论局部阻滞麻醉下全程清醒手术能很好保障脑功能区病灶的开颅切除,术中出声连续计数的语言功能监测对安全切除语言功能区肿瘤有重要定位指导意义。     

Application of magnetic resonance tractography in the perioperative planning of patients with eloquent region intra-axial brain lesions

We aimed to assess the role of preoperative diffusion tensor tractography (DTT) in the surgical planning and prognostication of the postoperative outcome of patients with lesions in the eloquent areas of the brain. From 2006 to 2009, 50 patients were preoperatively evaluated with DTT and image-guidance studies. Three-dimensional (3D) color trajectory maps of white-matter tracts adjacent to the lesions were reconstructed. The usefulness of tractography in perioperative planning was graded on a scale of 1 to 4. The postoperative outcomes were studied in relation to the pattern of tract involvement. The lesions included brain tumors in 40 patients, vascular malformations in five patients and other lesions in five patients. An awake craniotomy was performed in 19 patients. The tracts were only displaced in 72% of patients, completely infiltrated in 14% and had a combined pattern in 14%. DTT significantly altered the planning (score ?3) in 62% of patients. Patients with pure displacement had the best outcome, while those with infiltration had a poorer outcome. We conclude that tractography improves surgical safety and aids prognostication in surgery of patients with eloquent cortex lesions.     

导航辅助皮层功能拓扑定位在累及功能区致痫灶手术中的初步应用

目的 应用神经导航影像融合并结合皮层电刺激功能定位技术,初步实现三维可视化皮层功能拓扑定位,辅助累及皮层功能区致痫灶的手术,提高疗效.方法 1例药物难治性癫痫患者,行双侧皮层电极埋藏覆盖中央区,术后予皮层脑电图监测,并实施皮层电刺激定位功能区.神经导航系统融合头颅MRI和CT影像,三维可视化拓扑定位皮层功能和致痫灶,第二次手术在导航辅助定位保护功能区的前提下,行致痫灶切除术,对累及功能区的病变实施皮层热灼术.结果 患者成功埋藏32导、24导及6导皮层电极各一枚覆盖中央区,皮层脑电图监测捕获临床发作4次,定位致痫灶;皮层电刺激确定功能区.神经导航影像融合建立覆盖皮层电极的三维大脑模型,还原电生理资料,实现拓扑定位.手术成功实施病灶切除,术后无发作情况,无并发症.结论 应用神经导航影像融合技术,使作为脑-机接口的脑皮层电极技术与影像学技术相结合,将皮层电极的空间位置,精确融合在基于头颅MRI建立的大脑皮层解剖模型上,还原皮层脑电图和皮层电刺激结果,实现三维可视化拓扑定位,对于累及功能区致痫灶的神经外科手术具有重要指导意义.     

功能性磁共振导航引导切除中央区胶质瘤

目的 探讨功能性磁共振影像导航技术在功能区胶质瘤手术中的应用价值。方法 选择15例位于中央区附近的胶质瘤患者，进行术前运动区神经元细胞激活性刺激，同时进行功能成像，将数据进行统计学分析，获得激活功能区图像，输入神经导航系统进行图像融合，手术前进行注册、配准，手术中进行肿瘤与功能区的定位，在保护功能区的同时尽可能的切除肿瘤。结果 15例病人中除有4例病人术后出现短暂性肢体功能障碍加重外，其余患者均未出现永久性神经功能障碍。结论 功能性磁共振导航为毗邻中央区的胶质瘤手术，提供了一种直观可靠简便的功能区判定方法，提高了手术的安全性，减少了手术并发症。     

The special involvement of the rostrolateral prefrontal cortex in planning abilities: an event-related fMRI study with the Tower of London paradigm

Planning abilities are essential for the successful management of everyday life activities. Although several neuroimaging studies provide evidence that the prefrontal cortex is crucially involved in planning, the differential roles of its subregions are still a matter of debate. The aim of this study was to investigate the neural correlates of planning by focusing on the functional differentiation between the dorsolateral and rostrolateral prefrontal cortex using the Tower of London (ToL) task and a parametric event-related functional MRI design. In order to control for activations unspecific to planning, two control conditions were presented, which were matched for the length of single events in the ToL task. Seventeen right-handed healthy subjects participated in this study. All statistics were reported with corrections for multiple comparisons (p < 0.05). Compared to control conditions, activations in the ToL task were observed in the dorsolateral prefrontal cortex bilaterally, the right ventrolateral and left rostrolateral prefrontal cortex along with the thalamus, as well as in the parietal and premotor cortex bilaterally. Task complexity dependent analyses revealed that only the left rostrolateral prefrontal cortex showed a BOLD signal increase over the four planning levels, which could not be observed in the control conditions. Hence, current findings suggest that planning involves an extensive fronto-parieto-thalamic network. Within this network, the rostrolateral prefrontal cortex seems to be the only region that is exclusively reactive to planning specific processes, which we described in terms of simultaneous monitoring of internally generated and externally presented information.     

fMRI辅助脑功能区病变手术设计的应用

目的探讨功能性磁共振成像(fMRI)在脑运动区病变手术设计中的应用。方法对20例累及运动区的脑内占位病变病人术前行手握拳运动block激发模式fMRI，分析病变与运动区的关系及功能重塑情况，据此在手术中尽可能切除肿瘤并保留运动皮质的完整。结果肿瘤全切除6例，次全切除12例，部分切除2例。术前10例上肢肌力下降病人术后上肢肌力好转7例．余3例及术前肌力正常10例术后保持术前水平、结论fMRI用于运动区病变病人运动功能的客观评估和手术计划，对于降低手术带来功能缺陷的发生率具有重要意义。     

Functional connectivity of the anterior cingulate cortex predicts treatment outcome for rTMS in treatment-resistant depression at 3-month follow-up

Background and objectiveRepetitive transcranial magnetic stimulation (rTMS) is a first-line treatment for treatment-resistant depression (TRD). The mechanisms of action of rTMS are not fully understood, and no biomarkers are available to assist in clinical practice to predict response to rTMS. This study aimed to demonstrate that after-rTMS clinical improvement is associated with functional connectivity (FC) changes of the subgenual cingulate cortex (sgACC) and rostral anterior cingulate (rACC), and FC of sgACC and rACC might serve as potential predictors for treatment response.MethodsResting-state functional magnetic resonance imaging (rs-fMRI) data were collected within 1 week before rTMS initiation in 50 TRD patients to predict subsequent response to rTMS on the left dorsolateral prefrontal cortex (DLPFC). Follow-up rs-fMRI was obtained 12 weeks after completion of rTMS and neural correlates of rTMS in sgACC- and rACC-related FC patterns were compared to before rTMS data and with rs-fMRI from healthy participants.ResultsTreatment response was associated with lower FC of sgACC to right DLPFC and higher FC of rACC to left lateral parietal cortex (IPL) measured at baseline. Using sgACC-DLPFC and rACC-IPL connectivity as features, responder-nonresponder classification accuracies of 84% and 76% (end-of-treatment), 88% and 81% (3-month follow-up), respectively were achieved. Longitudinal rs-fMRI data analyses revealed that the hyperconnectivity between sgACC and visual cortex was normalized to a level which was comparable to that of healthy participants.ConclusionsBrain activity patterns in depression are predictive of treatment response to rTMS, and longitudinal change of brain activity in relevant brain circuits after rTMS is associated with treatment response in depression. Target engagement paradigms may offer opportunities to increase the efficacy of rTMS in TRD by optimal selection of patients for treatment.Trial registrationClinicalTrials.gov Identifiers: NCT01887782 and NCT02800226.     

A Meta‐analysis on the neural basis of planning: Activation likelihood estimation of functional brain imaging results in the Tower of London task

The ability to mentally design and evaluate series of future actions has often been studied in terms of planning abilities, commonly using well‐structured laboratory tasks like the Tower of London (ToL). Despite a wealth of studies, findings on the specific localization of planning processes within prefrontal cortex (PFC) and on the hemispheric lateralization are equivocal. Here, we address this issue by integrating evidence from two different sources of data: First, we provide a systematic overview of the existing lesion data on planning in the ToL (10 studies, 211 patients) which does not indicate any evidence for a general lateralization of planning processes in (pre)frontal cortex. Second, we report a quantitative meta‐analysis with activation likelihood estimation based on 31 functional neuroimaging datasets on the ToL. Separate meta‐analyses of the activation patterns reported for Overall Planning (537 participants) and for Planning Complexity (182 participants) congruently show bilateral contributions of mid‐dorsolateral PFC, frontal eye fields, supplementary motor area, precuneus, caudate, anterior insula, and inferior parietal cortex in addition to a left‐lateralized involvement of rostrolateral PFC. In contrast to previous attributions of planning‐related brain activity to the entire dorsolateral prefrontal cortex (dlPFC) and either its left or right homolog derived from single studies on the ToL, the present meta‐analyses stress the pivotal role specifically of the mid‐dorsolateral part of PFC (mid‐dlPFC), presumably corresponding to Brodmann Areas 46 and 9/46, and strongly argue for a bilateral rather than lateralized involvement of the dlPFC in planning in the ToL. Hum Brain Mapp 38:396–413, 2017. © 2016 Wiley Periodicals, Inc.     

Mapping the central effects of chronic ketamine administration in an adolescent primate model by functional magnetic resonance imaging (fMRI)

Ketamine, a noncompetitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, is capable of triggering excessive glutamate release and subsequent cortical excitation which may induce psychosis-like behavior and cognitive anomalies. Growing evidence suggests that acute ketamine administration can provoke dose-dependent positive and negative schizophrenia-like symptoms. While the acute effects of ketamine are primarily linked to aberrant activation of the prefrontal cortex and limbic structures with elevated glutamate and dopamine levels, the long-term effects of ketamine on brain functions and neurochemical homeostasis remain incompletely understood. In recent years, reports of ketamine abuse, especially among young individuals, have surged rapidly, with profound socioeconomic and health impacts. We herein investigated the chronic effects of ketamine on brain function integrity in an animal model of adolescent cynomolgus monkeys (Macaca fascicularis) by functional magnetic resonance imaging (fMRI). Immunohistochemical study was also conducted to examine neurochemical changes in the dopaminergic and cholinergic systems in the prefrontal cortex following chronic ketamine administration. Our results suggest that repeated exposure to ketamine markedly reduced neural activities in the ventral tegmental area, substantia nigra in midbrain, posterior cingulate cortex, and visual cortex in ketamine-challenged monkeys. In contrast, hyperfunction was observed in the striatum and entorhinal cortex. In terms of neurochemical and locomotive changes, chronically ketamine-challenged animals were found to have reduced tyrosine hydroxylase (TH) but not choline acetyltransferase (ChAT) levels in the prefrontal cortex, which was accompanied by diminished total movement compared with the controls. Importantly, the mesolimbic, mesocortical and entorhinal-striatal systems were found to be functionally vulnerable to ketamine's chronic effects. Dysfunctions of these neural circuits have been implicated in several neuropsychiatric disorders including depression, schizophrenia and attention deficit disorder (ADD). Collectively, our results support the proposition that repeated ketamine exposure can be exploited as a pharmacological paradigm for studying the central effects of ketamine relevant to neuropsychiatric disorders.     

Premotor cortex and the conditions for movement in monkeys (Macaca fascicularis)

Cortical association areas direct their influence on motor cortex via premotor and supplementary motor cortex. In the present experiment premotor cortex was removed bilaterally in monkeys. The monkeys were unable to relearn a visual conditional motor task on which the correct action is specified by visual cues. It was shown that the same monkeys were able to learn a non-motor visual conditional task on which the visual cues specified which object should be chosen. It is concluded that the monkeys are only impaired when they must recall a movement from memory on the basis of a visual cue.     

Application of phase sensitive imaging (PSI) for hemorrhage diagnosis in pituitary adenomas

Abstract

Objective: Intratumoral hemorrhaging is a common occurrence in pituitary adenomas. Asymptomatic pituitary apoplexies have become more frequently diagnosed due to recent advances in magnetic resonance (MR) imaging. The purpose of this study was to investigate the usefulness of phase sensitive imaging (PSI) in the diagnosis of hemorrhages within pituitary adenomas.

Patients and methods: PSI methodology was applied to 28 patients with surgically diagnosed pituitary macroadenomas, and compared with conventional methods. No patients presented with sudden onset of apoplectic symptoms. A 3·0 T MR unit was used to examine all patients before surgery.

Results: Seventeen of 28 cases exhibited a hemorrhage component on PSI. However, hemorrhaging was demonstrated in 13 of 28 cases by T2-weighted imaging (T2WI). Hemorrhaging was detected in pituitary adenomas by PSI, but not by T2WI, in four of 17 cases. Poor visualization of the hemorrhage in the sellar turcica was a drawback, which was due to PSI artifacts.

Conclusion: We suggest that PSI be used to provide diagnostic assistance for pituitary apoplexies.     

Manganese-enhanced MR imaging (MEMRI) combined with electrophysiology in the study of cross-modal plasticity in binocularly blind rats

Our study aimed to determine and verify the establishment of visual to auditory cross-modal plasticity using manganese-enhanced MR imaging (MEMRI) combined with examinations of the visual evoked potential (VEP), auditory brainstem response (ABR) and bilateral visual cortex response to a bilateral auditory stimulus (AVR). Fourteen healthy male Sprague-Dawley newborn rats were randomly divided into 2 groups (n = 7 per group). Optic nerve transection was performed in the 7 rats of Group A three weeks after birth to obtain binocularly blind models, and the 7 rats of Group B were maintained as the control group. The VEP was measured to ensure complete binocular blindness. Four months after the operation, MnCl₂ was injected into the left inner ear perilymph of all rats, and an MRI examination was performed 24 h after injection. Then, ABR and AVR were measured to detect the generation of auditory compensatory function. The results of the VEP have confirmed complete binocular blindness. The normalized signal intensity of the bilateral medial geniculate nucleus, auditory cortex, visual center (including the lateral geniculate nucleus, superior colliculus and visual cortex) and right hippocampus in binocularly blind rats was significantly increased compared with that in normal rats (P ≤ 0.005), which was confirmed by measurement of the ABR and AVR. Our results suggested that MEMRI combined with electrophysiology can show changes in the auditory and visual pathways of binocularly blind rats and demonstrate the generation of an auditory compensatory pathway.     

Structural evidence for the neurotoxicity of methylamphetamine in the frontal cortex of gerbils (Meriones unguiculatus): a light and electron microscopical study

Morphological alterations in the CNS were investigated in young gerbils treated with two injections of methylamphetamine (Meth) 8 h apart and killed 3, 5 and 7 days after treatment. In gerbils treated with 2 X 35 mg/kg or higher doses of Meth and prepared according to the terminal degeneration method of Gallyas et al. (Stain Technol., 55 (1980) 299-306), silver precipitates occurred in lamina II and III of the frontal cortex. Electron microscopical studies showed degenerated terminals and neurons. After 3 days of survival we found affected but not degenerating pyramidal cells in the same area. Light microscopical observations after 5 and 7 days of survival indicate a recovery of these cells. All described morphological alterations could be suppressed when Meth was administered in combination with haloperidol. These data and the comparison of aminergic projections to the cortex are discussed on the basis of evidence that Meth induces alteration of mesocortical dopamine nerve fibers and their postsynaptic structures in the frontal cortex (FC). Present results indicate that morphological alterations in young gerbils after Meth treatment are limited to the FC. This is in contrast to the literature, which describes neurotoxic effects of Meth in the neostriatum of various adult mammalian species.     

The critical role of the inferior frontal cortex in establishing a prediction model for generating subsequent mismatch negativity (MMN): A TMS-EEG study

BackgroundThe prediction violation account of automatic or pre-attentive change detection assumed that the inferior frontal cortex (IFC) is involved in establishing a prediction model for detecting unexpected changes. Evidence supporting the IFC’s contribution to prediction model is mainly based on the Mismatch Negativity (MMN) to deviants violating predictions that are established based on the frequently presented standard events. However, deviant detection involves processes, such as events comparison, other than prediction model establishment.ObjectiveThe current study investigated the critical role of the IFC in establishing a prediction model during standards processing for subsequent deviant detection.MethodsTranscranial Magnetic Stimulation (TMS) was applied at the IFC to disrupt the processing of the initial 2 or 5 standards of a 3-, 6-, or 9-standard train, while the MMN responses to pitch deviant presented after the standard trains were recorded and compared.ResultsAn abolishment of MMN was only observed when TMS was delivered to the IFC at the initial 2 standards of the 3-standard train, but not at the initial 5 standards, or when TMS at the vertex or TMS sound recording was applied. The MMNs were also preserved when IFC TMS, vertex TMS, or TMS sound recording was applied at the initial 2 or 5 standards of longer trains.ConclusionThe IFC plays a critical role in processing the initial standards of a short standard train for subsequent deviant detection. This result is consistent with the prediction violation account that the IFC is important for establishing the prediction model.     

Biochemical evidence for glutamate and/or aspartate as neurotransmitters in fibers from the visual cortex to the lateral posterior thalamic nucleus (pulvinar) in rats

The effects of visual cortex ablation on several neurotransmitter parameters in the lateral posterior thalamic nucleus (pulvinar) in rats have been investigated. We found a 57% decrease in high affinity uptake ofd-[³H]aspartate in the pulvinar after ablation of the ipsilateral visual cortex. The KCl-evoked release of exogenousd-[³H]aspartate and endogenous glutamate were decreased by 33 and 37%, respectively. Moreover, the contents of endogenous glutamate and aspartate were decreased by 35%, each. The glutamate decarboxylase and choline acetyltransferase activities and the contents of other amino acids were not affected by the lesion. Our biochemical data indicate that glutamate and/or aspartate may be transmitters in the fibers from visual cortex to pulvinar in rats.     

Racial disparity in recommendation for surgical resection of skull base chondrosarcomas: A Surveillance,Epidemiology, and End Results (SEER) analysis

IntroductionThere is increased appreciation of racial disparities in the delivery of neurosurgical care. Here, we explore whether race influences surgical recommendations in the management of skull base chondrosarcomas.MethodsWe identified 493 patients with skull base chondrosarcoma using the Surveillance, Epidemiology, and End Results (SEER) registry (November 2017 submission). Regression analyses were performed to identify demographic variables associated with recommendation against surgery. Univariate and multivariate cox proportional hazards models were used for survival analysis.ResultsIn a univariate analysis, we found that the African-American race was associated with an increased likelihood of surgeon recommendation against surgery (OR = 4.416, 95% CI = 1.893–10.302, p = 0.001). This association remained robust in the multivariate model that controlled for other covariates, including age of diagnosis (OR = 5.091, 95% CI = 2.127–12.187, p < 0.001). For patients who received a recommendation against surgery, the likelihood of dying from non-chondrosarcoma causes was comparable between Caucasian and African-American patients, suggesting that the prevalence and severity of medical conditions that increase the risk of death were comparable between these cohorts (HR = 0.466, 95% CI = 0.057–3.802, p = 0.475). The likelihood of dying from chondrosarcoma was comparable between Caucasian and African-American patients who underwent surgery (HR = 0.982, 95% CI = 0.353–2.732, p = 0.973), suggesting absence of race-specific surgical benefits.ConclusionWe identified a racial disparity against African-Americans in recommendations for surgical resection of skull base chondrosarcomas.     

Diffuse perineuronal nets and modified pyramidal cells immunoreactive for glutamate and the GABA(A) receptor alpha1 subunit form a unique entity in rat cerebral cortex

Perineuronal nets (PNs) consisting of polyanionic chondroitin sulfate proteoglycans (CSPG) and other extracellular matrix components create an exceptional microenvironment around certain types of neurons. In rat neocortex, three types of PNs can be distinguished after staining with Wisteria floribunda agglutinin (WFA) by their different morphological structure: lattice-like PNs associated with subpopulations of nonpyramidal neurons, weakly labeled PNs showing a pyramidal morphology, and diffuse PNs that possess a thick, strongly labeled matrix sheath located mainly in layer VIb above the white matter. The type of neuron surrounded by diffuse nets has not been described so far. This study is focused on the cytochemical and morphological characteristics of neurons associated with diffusely contoured PNs in rat parietal cortex using immunocytochemical staining, intracellular injection, and retrograde tracing methods. Cells surrounded by diffuse PNs were glutamate-immunoreactive in contrast to nonpyramidal, net-associated neurons that showed immunoreactivity for GABA, the calcium-binding protein parvalbumin and the potassium channel subunit Kv3.1b. Both groups of PN-ensheathed cells were mostly immunoreactive for the GABA(A) receptor alpha1 subunit. Lucifer Yellow-injected neurons surrounded by diffuse PNs displayed the morphological properties of modified pyramidal cells with intracortical main axons. Many neurons with diffuse PNs were retrogradely labeled over a long distance after Fluoro-Gold tracer injection in the parietal cortex, but remained unlabeled after intrathalamic injection. We conclude that neurons associated with diffuse PNs are a subpopulation of glutamatergic modified pyramidal cells that could act as excitatory long-range intracortically projecting neurons.