[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION: Inferior temporal brain areas are known to have sub-regions that are specialized for processing specific categories of stimuli; the "fusiform face area" is the most well known of these. These areas have primarily been identified using functional MRI (fMRI). Because of the ~5 seconds timescale fMRI averages over, the fine temporal dynamics of category-specific processing remain unknown. METHODS: In this study, electrocorticographic (ECoG) electrodes were placed on the inferior temporal brain surface for seizure monitoring. Simple pictures of faces and houses (with blank screen in between) were shown for 400 ms at a time. A real-time correlate of local neural population activity, so-called "broadband spectral change," was extracted from the ECoG power spectrum. RESULTS: Broadband change reveals a robust category-specific response to each type of stimulus in adjacent cortical sites (1-2 cm apart), with face-specific loci lateral to house specific loci. Single stimuli were classified with ~98% accuracy, with peak inferotemporal response 200-250 ms post-presentation. Portions of the percept-to-percept response variability could be explained by stimulus repetition: peak activity is faster and the total activity is greater for novel stimuli (e.g. faces following houses and vice-versa), than it is for repeated within-class stimuli. CONCLUSION: Repetition suppression has been proposed as either an effect of the engaged visual pathway being optimized for efficiency by requiring less population activity for processing - with accelerated dynamics, vs being optimized for novelty by allocating more computational resources for novel stimuli. These findings demonstrate that, at the population level, the brain is optimized for novelty. Novel types stimuli are allocated more computational power - with faster processing time - from category-specific inferotemporal neuronal populations. Journal of Neuro-Oncology Award Copyright (C) by the Congress of Neurological Surgeons
[Show abstract][Hide abstract] ABSTRACT: The use of both awake surgery and intraoperative MRI (iMRI) has been reported to optimize the maximal safe resection of gliomas. However, there has been little research into combining these two demanding procedures. We report our unique experience with, and methodology of, awake surgery in a movable iMRI system, and we quantitatively evaluate the contribution of the combination on the extent of resection (EOR) and functional outcome of patients with gliomas involving language areas. From March 2011 to November 2011, 30 consecutive patients who underwent awake surgery with iMRI guidance were prospectively investigated. The EOR was assessed by volumetric analysis. Language assessment was conducted before surgery and 1week, 1month, 3months and 6months after surgery using the Aphasia Battery of Chinese. Awake language mapping integrated with 3.0Tesla iMRI was safely performed for all patients. An additional resection was conducted in 11 of 30 patients (36.7%) after iMRI. The median EOR significantly increased from 92.5% (range, 75.1-97.0%) to 100% (range, 92.6-100%) as a result of iMRI (p<0.01). Gross total resection was achieved in 18 patients (60.0%), and in seven of those patients (23.3%), the gross total resection could be attributed to iMRI. A total of 12 patients (40.0%) suffered from transient language deficits; however, only one (3.3%) patient developed a permanent deficit. This study demonstrates the potential utility of combining awake craniotomy with iMRI; it is safe and reliable to perform awake surgery using a movable iMRI.
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to describe the clinical features and to evaluate the surgical treatment outcomes of pediatric patients with cerebral cavernous malformations (CCM). We investigated 85 children (53 boys and 32 girls), aged from 6 months to 17.9 years with CCM. Seizures and symptomatic hemorrhages, which were the most frequent symptoms, occurred in 81 patients. Nine patients had a positive family history of CCM. Eighty patients underwent microsurgical treatment after strict operative indications were met. Neuronavigation, combined with intraoperative ultrasonography or functional MRI, was used for precise localization of the lesions. The principles of minimally invasive techniques were followed during surgery. A total of 89 lesions were removed in 80 patients, and there were no deaths. During their hospital stay, only nine patients suffered from postoperative seizures, which were controlled with medication. Postoperative neurological deficits improved in 27 patients, were unchanged in nine, and worsened in two. With the help of advanced neuroimaging, a satisfactory surgical outcome was achieved for 10 lesions located in eloquent brain areas and four lesions in the brain stem. A follow-up study of 66 patients showed that all of these patients remained seizure-free, and nine patients with postoperative neurological deficits gradually recovered. Microsurgical treatment should be performed early for pediatric patients with CCM. Accurate localization of the lesions and the use of minimally invasive techniques and functional MRI monitoring were the key features of the surgical procedures.