Montreal Neurological Institute Research Articles

Lateral or Medial Surgical Approaches for Thalamic Gliomas Resection?

This study aimed to investigate the selection, safety, and prognosis of medial (transcorpus callosal) and lateral (translateral brain gyrus) approaches for adult thalamic glioma resection. The medical records of adult patients with thalamic glioma between March 2006 and March 2016 in Huashan Hospital were reviewed. The probabilistic map of the gliomas was shown in Montreal Neurological Institute (MNI) space, and a paralleling midline was delineated to decide the approach. The extent of resection, complications, adjuvant treatment, and survival data were analyzed. A literature review was also conducted. Fifty-three patients with thalamic glioma were enrolled. Eighteen patients received tumor resection by a medial approach and 35 by a lateral approach. The probabilistic map based on 20 patients showed that 9 gliomas with ≥45% located in the medial side were treated medially and the other 11 gliomas were treated laterally. Both approaches achieved adequate extent of resection with similar morbidity. Kaplan-Meier analysis showed no significant difference of overall survival by a transcorpus callosal or translateral brain gyrus approach. Total resection (TR) or subtotal resection (STR) (P= 0.0003), radiochemotherapy (P < 0.0001), and low-grade glioma (P= 0.031) were correlated with better OS. Multivariate Cox regression analysis showed that TR/STR (P= 0.007; 95% confidence interval, 1.345-6.287) and radiochemotherapy (P < 0.0001; 95% confidence interval, 4.740-71.569) were independent prognostic factors for adult thalamic gliomas. Both medial and lateral approaches are feasible and adequate for resection of thalamic gliomas. The paramidline paralleling midline crossing the genu of the internal capsule could help make the choice. TR/STR, radiochemotherapy, and low-grade glioma could benefit the prognosis.

Morphology and Spatial Probability Maps of the Horizontal Ascending Ramus of the Lateral Fissure.

The horizontal ascending ramus of the lateral fissure (half) is a characteristic sulcus of the ventrolateral frontal cortex that forms the morphological boundary between the pars triangularis and the pars orbitalis of the inferior frontal gyrus. The present study examined the morphology of this sulcus to provide a means of identifying it accurately with magnetic resonance imaging (MRI). Voxels within the half were labeled in 50 in vivo MRI volumes (1.5T) that had been linearly registered to the Montreal Neurological Institute stereotaxic space and the morphology of the half was categorized based on relations with neighboring sulci. The spatial variability and extent of the half were then quantified across subjects using volumetric (MINC Toolkit) and surface (FreeSurfer) spatial probability maps. The half could be identified in 95% of hemispheres, and the main morphological patterns were classified into three categories: Types I, II, and III. There were no statistically significant interhemispheric differences in the frequency of the half or its morphological patterns. Understanding the details of the sulcal morphology of this ventrolateral region is critical for an accurate interpretation of the location of activation peaks generated in functional neuroimaging studies investigating language, working memory, and other cognitive processes.

92Transcatheter aortic valve implantation improves cerebral blood flow and cognitive function in elderly patients with aortic stenosis - Brain perfusion SPECT imaging study

Abstract Background Cognitive impairment and depression are commonly noted in elderly frail patients with severe aortic stenosis (AS). However, their mechanisms and reversibility after treatment remain remain to be examined. Purpose In this study, we examined whether transcatheter aortic valve implantation (TAVI) increases cerebral blood flow (CBF) in cognitive/emotional brain areas, such as the hippocampus, in the elderly patients with severe AS. Methods We examined consecutive 15 right-handed patients with severe AS who were eligible for TAVI (median age 83.2 years, 12 (80%) women). We evaluated the following assessments both at baseline and 3 months after TAVI. Frailty was evaluated based on Fried scale, which consists of 5 items, including gait speed, cognitive function, weight loss, exhaustion, and inactivity. Frail and pre-frail were defined as greater than 3 and 1∼2 in the scale, respectively. Cognitive and emotional status were evaluated with Logical Memory (LM) II, Mini Mental State Examination (MMSE), and geriatric depression scale (GDS). Lower LM II (less than 4 points) and MMSE (less than 24 points) and higher GDS (more than 6 points) indicate worse memory, general cognitive function, and depressive symptoms, respectively. CBF images were recorded with 99mTc single-photon emission computed tomography and were analyzed using SPM12. Briefly, CBF images were firstly normalized to the standard Montreal Neurological Institute space. Then, a voxel-wise parametric analysis was conducted between normalized CBF images at baseline and those after TAVI (P&lt;0.005 at each voxel). Continuous variables were presented as mean ± standard error (SE). Normality was assessed using the Shapiro-Wilk test. Continuous variables were compared with the use of paired t test. Linear mixed-model analysis was performed to evaluate changes in neuropsychological tests and CBF over time. Results In the present study, all patients were not robust but pre-frail (47.3%) or frail (53.7%). LM II score was significantly improved at 3 months after TAVI compared with baseline (baseline, 8.7 vs. 3 months, 13.8, P&lt;0.01) (Figure A), whereas no significant changes in MMSE or GDS scores were noted (baseline, 24.6 vs. 3 months, 25.2 for MMSE; baseline, 4.3 vs. 3 months, 4.2 for GDS). Importantly, although no patients showed clinical symptoms or signs for transient ischemic attack or stroke after TAVI, CBF in the local regions, including the right hippocampus, was significantly increased after TAVI compared with baseline (P&lt;0.005 at each voxel) (green arrowheads) (Figure B). Furthermore, CBF in the right hippocampus were positively correlated with LM II scores (P=0.017) (Figure C). Figure 1 Conclusions These results provide the first evidence that TAVI improves cerebral perfusion (especially that in the hippocampus) and cognitive functions in elderly patients with severe AS.

Neural Correlates of Urinary Retention in Lateral Medullary Infarction.

PurposeThe brainstem plays an important role in the control of micturition, and brainstem strokes are known to present with micturition dysfunction. Micturition dysfunction in cases of lateral medullary infarction (LMI) is uncommon, but often manifests as urinary retention. In this study, we investigated the neuro-anatomical correlates of urinary retention in patients with LMI.MethodsThis was a hospital-based retrospective study conducted in the neurology unit of a quaternary-level teaching hospital. Inpatient records from January 2008 to May 2018 were searched using a computerized database. Cases of isolated LMI were identified and those with micturition dysfunction were reviewed. MRI brain images of all patients were viewed, and individual lesions were mapped onto the Montreal Neurological Institute (MNI) space manually using MRIcron. Nonparametric mapping toolbox software was used for voxel-based lesion-symptom analysis. The Liebermeister test was used for statistical analysis, and the resultant statistical map was displayed on the MNI template using MRIcron.ResultsDuring the study period, 31 patients with isolated LMI were identified. Their mean age was 48 years and 28 (90%) were male. Six of these patients (19%) developed micturition dysfunction. All 6 patients had urinary retention and 1 patient each had urge incontinence and overflow incontinence. In patients with LMI, the lateral tegmentum of the medulla showed a significant association with urinary retention.ConclusionsIn patients with isolated LMI, we postulate that disruption of the descending pathway from the pontine micturition centre to the sacral spinal cord at the level of the lateral tegmentum results in urinary retention.

A human brain tau PET template in MNI space for the voxel-wise analysis of Alzheimer’s disease

BackgroundPositron emission tomography (PET) imaging techniques of tau retention in the human brain are important for mechanistic studies of Alzheimer's disease (AD). However, the method for effectively conducting voxel-wise analysis on tau PET images still needs to be improved. In the present study, we introduced a tau PET template for the human brain in Montreal Neurological Institute (MNI) space for the convenient and reliable voxel-wise analysis of tau PET images in AD studies. New methodTwenty-four AD patients and 22 controls were used to construct the tau PET template, and an additional 22 subjects (11 AD patients and 11 controls) were enrolled to evaluate the performance of the template. Thirty regions (28 cortical and 2 subcortical regions) throughout the brain were used to evaluate the accuracy of the tau PET template. ResultsA significant relationship (R2 = 0.848, P < 0.001) was found between the standardized uptake value ratios (SUVRs) obtained by the tau PET template and magnetic resonance imaging (MRI)-aided approach, and the paired-sample t-test showed no significant difference (P = 0.62) between the values. These two approaches revealed consistent brain regions with high tau retention. Comparison with existing methodsThe tau PET template was comparable with the traditional MRI-aided strategy. Furthermore, compared to the MRI-aided approach, the tau PET template was more convenient and easier to use. More importantly, in most clinical settings, AD patients who underwent PET/computed tomography (CT) typically do not have MR images, in which case the traditional MRI-aided approach would not be applicable. Our tau PET template overcame this deficiency and may serve as a useful tool in AD research. ConclusionsThis tau PET template performed well and may serve as a useful tool in future AD studies.

Identification and Research of Adhd and Healthy Controls using Fmri

Analyzing the brain regions for different activations corresponding to the activation input for an experimental setup of task functional MRI or a resting state functional Magnetic Resonance Imaging(fMRI) for a diagnosed or healthy control is a challenging issue as the processing data is voluminous 4D data with nearly 1,51,552 voxels for a single volume of 261 scans fMRI. The data considered for analysis consists of 10 healthy controls and 10 Attention Deficit Hyperactivity Disorder(ADHD) fMRI. The workflow starts with preprocessing the individual scan for realignment, coregistration and Normalisation to Montreal Neurological Institute (MNI) space. Single site scan visit consists of 64x64x37 voxels. Seventy independent components are obtained from processed data by data reduction, Independent Component Analysis (ICA) calculation, Back reconstruction and Component Calibration. ICA performs satisfactorily well on temporal and spatial localization. Visual medial network activation is pronounced in ADHD Controls than in healthy people. Sagittal, Axial and Coronal view of ADHD controls is obtained as component number 42.The analysis is further used for the automatic classification of healthy controls and ADHD people.

A Novel Framework for Spatial Normalization of Dose Distributions in Voxel-Based Analyses of Brain Irradiation Outcomes

Voxel-based population analyses (VBAs) are gaining momentum in radiation therapy (RT) outcome modeling. VBAs rely on the accurate spatial normalization (SN) of different patients’ anatomies on a common coordinate system (CCS) by inter-patient elastic registration of planning CTs. VBA has been applied to different toxicity endpoints and anatomical regions. However, as for brain applications, the cerebral anatomy, while being well characterized by several MRI modalities, shows a poor CT contrast, thus resulting in potentially large inaccuracies of VBAs based on the planning CT alone. Aim of the present study was to devise and evaluate a novel SN framework for VBA in brain irradiation based on multimodal imaging. We analyzed 43 brain tumor patients treated at a single institution with proton therapy. All patients underwent a 3D T1-weighted (T1w) MR sequence. The Montreal Neurological Institute (MNI) space [Evans et al. 1993] was chosen as CCS. The SN pipeline was: 1. Intra-patient affine registration of CT to T1w; 2. Inter-patient B-spline registration of T1w to MNI; 3. doses propagation to MNI by applying the deformation fields of steps (1) and (2). To specifically evaluate the accuracy of dose SN, the dose organ overlap (DOO) scores [Acosta et al. 2013] were computed on White Matter (WM), Gray Matter (GM) and liquor (CSF) before (DOOpre) and after (DOOpost) SN. In addition, the trends in the DOOs distribution were investigated: a Gaussian mixture model of the 6D data (DOOpre and DOOpost for each structure) was selected by choosing the number of clusters that maximizes the average silhouette over all data, and each 6D point (i.e. patient) was assigned to the cluster corresponding to the maximum posterior probability. The selected Gaussian mixture model included 3 clusters. While clusters 2 and 3 exhibited acceptable DOOpost scores on parenchyma (> 0.5), cluster 1 was associated to very low values of DOOpost. The paired comparison of the DOOpre and DOOpost showed a significant improvement of organ dose matching, both in the whole cohort and in clusters 2 and 3. The presented study represents the first attempt to assess a SN procedure specifically tailored to the needs of brain dose VBAs. The DOO scores show the overall accuracy of the devised SN procedure. In addition, the Gaussian mixture model provides a formal criterion for excluding from the statistical analysis the few patients (7%) on whom the SN failed to produce acceptable results. We believe that the implemented framework lays the groundwork for future reliable VBAs in brain irradiation studies.Abstract 214; Table 1Patients (n)DOOWMGMCSFPrePostpPrePostpPrePostpAll (43)0.14 ± 0.110.62 ± 0.18<10-50.16 ± 0.080.60 ± 0.12<10-50.12 ± 0.090.42 ± 0.13<10-5Cluster 1 (3)0.03 ± 0.010.09 ± 0.090.320.19 ± 0.090.36 ± 0.130.100.10 ± 0.040.19 ± 0.060.27Cluster 2 (4)0.41 ± 0.060.62 ± 0.180.050.32 ± 0.030.56 ± 0.110.020.33 ± 0.080.52 ± 0.090.01Cluster 3 (36)0.12 ± 0.060.66 ± 0.11<10-50.14 ± 0.060.63 ± 0.10<10-50.09 ± 0.060.42 ± 0.12<10-5 Open table in a new tab

Development and validation of the automated imaging differentiation in parkinsonism (AID-P): a multicentre machine learning study

There is a critical need to develop valid, non-invasive biomarkers for Parkinsonian syndromes. The current 17-site, international study assesses whether non-invasive diffusion MRI (dMRI) can distinguish between Parkinsonian syndromes. We used dMRI from 1002 subjects, along with the Movement Disorders Society Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS III), to develop and validate disease-specific machine learning comparisons using 60 template regions and tracts of interest in Montreal Neurological Institute (MNI) space between Parkinson's disease (PD) and Atypical Parkinsonism (multiple system atrophy - MSA, progressive supranuclear palsy - PSP), as well as between MSA and PSP. For each comparison, models were developed on a training/validation cohort and evaluated in a test cohort by quantifying the area under the curve (AUC) of receiving operating characteristic (ROC) curves. In the test cohort for both disease-specific comparisons, AUCs were high in the dMRI + MDS-UPDRS (PD vs. Atypical Parkinsonism: 0·962; MSA vs. PSP: 0·897) and dMRI Only (PD vs. Atypical Parkinsonism: 0·955; MSA vs. PSP: 0·926) models, whereas the MDS-UPDRS III Only models had significantly lower AUCs (PD vs. Atypical Parkinsonism: 0·775; MSA vs. PSP: 0·582). This study provides an objective, validated, and generalizable imaging approach to distinguish different forms of Parkinsonian syndromes using multi-site dMRI cohorts. The dMRI method does not involve radioactive tracers, is completely automated, and can be collected in less than 12 minutes across 3T scanners worldwide. The use of this test could thus positively impact the clinical care of patients with Parkinson's disease and Parkinsonism as well as reduce the number of misdiagnosed cases in clinical trials.

One-year Follow-up Study of Hippocampal Subfield Atrophy in Alzheimer's Disease and Normal Aging.

In this study, we investigated the effect of hippocampal subfield atrophy on the development of Alzheimer's disease (AD) by analyzing baseline magnetic resonance images (MRI) and images collected over a one-year follow-up period. Previous studies have suggested that morphological changes to the hippocampus are involved in both normal ageing and the development of AD. The volume of the hippocampus is an authentic imaging biomarker for AD. However, the diverse relationship of anatomical and complex functional connectivity between different subfields implies that neurodegenerative disease could lead to differences between the atrophy rates of subfields. Therefore, morphometric measurements at subfield-level could provide stronger biomarkers. Hippocampal subfield atrophies are measured using MRI scans, taken at multiple time points, and shape-based normalization to a Montreal neurological institute (MNI) ICBM 152 nonlinear atlas. Ninety subjects were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI), and divided equally into Healthy Controls (HC), AD, and mild cognitive impairment (MCI) groups. These subjects underwent serial MRI studies at three time-points: baseline, 6 months and 12 months. We analyzed the subfield-level hippocampal morphometric effects of normal ageing and AD based on radial distance mapping and volume measurements. We identified a general trend and observed the largest hippocampal subfield atrophies in the AD group. Atrophy of the bilateral CA1, CA2- CA4 and subiculum subfields was higher in the case of AD than in MCI and HC. We observed the highest rate of reduction in the total volume of the hippocampus, especially in the CA1 and subiculum regions, in the case of MCI. Our findings show that hippocampal subfield atrophy varies among the three study groups.

Distributed Global Functional Connectivity Networks Predict Responsiveness to L-DOPA and Subthalamic Deep Brain Stimulation

Abstract INTRODUCTION Brain circuit dysfunction in Parkinson's disease (PD) involves an extensive global network. A distinctive basal ganglia resting-state functional connectivity (rsFC) pattern has been linked with the ranked response to L-DOPA. We therefore sought to investigate global rsFC patterns associated with response to L-DOPA and to subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with advanced PD. METHODS A total of 19 patients underwent 3-Tesla resting-state functional magnetic resonance imaging (rsfMRI) in the ON-medication state prior to STN DBS. Improvement in UPDRS-III hemibody scores were assessed following L-DOPA therapy and STN DBS. Global rsFC was measured between regions-of-interest (ROIs) defined by the Automated Anatomical Labeling (AAL) atlas and the Montreal Neurologic Institute (MNI) PD25 subcortical atlas. Seed- and network-level correlations were made with an FDR-P &lt; .005. Graph theoretical analysis was performed with an analysis threshold of FDR-P &lt; .005; and then looking at the top 15% of edges. RESULTS Response to L-DOPA and to DBS displayed cerebellar desynchronization with bilateral thalami and synchronization with bilateral ventromedial prefrontal cortices (vmPFC). L-DOPA response was additionally associated with desynchronization between the vmPFC and the fusiform gyrus. Meanwhile, DBS response was associated with more widespread areas, which have been implicated in visuomotor control and planning. Graph theory analysis revealed that DBS response was inversely related to global efficiency of the thalamus and putamen bilaterally. No significant graph metrics were found relative to L-DOPA response. CONCLUSION Response to DBS and to L-DOPA share similar characteristics, particularly in cerebello-thalamo-cortical circuits, including those that play a role in planning, learning, decision-making, and reward-based behavior. Preservation of distributed networks involved in visuomotor control and network integration of striatothalamocortical circuits appear to predict DBS response. These findings shed a light on the mechanism of action of DBS and L-DOPA and may help serve as useful treatment response biomarkers.

Emotion Regulation of Hippocampus Using Real-Time fMRI Neurofeedback in Healthy Human.

Real-time functional magnetic resonance imaging neurofeedback (rtfMRI-NF) is a prospective tool to enhance the emotion regulation capability of participants and to alleviate their emotional disorders. The hippocampus is a key brain region in the emotional brain network and plays a significant role in social cognition and emotion processing in the brain. However, few studies have focused on the emotion NF of the hippocampus. This study investigated the feasibility of NF training of healthy participants to self-regulate the activation of the hippocampus and assessed the effect of rtfMRI-NF on the hippocampus before and after training. Twenty-six right-handed healthy volunteers were randomly assigned to the experimental group receiving hippocampal rtfMRI-NF (n = 13) and the control group (CG) receiving rtfMRI-NF from the intraparietal sulcus rtfMRI-NF (n = 13) and completed a total of four NF runs. The hippocampus and the intraparietal sulcus were defined based on the Montreal Neurological Institute (MNI) standard template, and NF signal was measured as a percent signal change relative to the baseline obtained by averaging the fMRI signal for the preceding 20 s long rest block. NF signal (percent signal change) was updated every 2 s and was displayed on the screen. The amplitude of low-frequency fluctuation and regional homogeneity values was calculated to evaluate the effects of NF on spontaneous neural activity in resting-state fMRI. A standard general linear model (GLM) analysis was separately conducted for each fMRI NF run. Results showed that the activation of hippocampus increased after four NF training runs. The hippocampal activity of the experiment group participants was higher than that of the CG. They also showed elevated hippocampal activity and the greater amygdala–hippocampus connectivity. The anterior temporal lobe, parahippocampal gyrus, hippocampus, and amygdala of brain regions associated with emotional processing were activated during training. We presented a proof-of-concept study using rtfMRI-NF for hippocampus up-regulation in the recall of positive autobiographical memories. The current study may provide a new method to regulate our emotions and can potentially be applied to the clinical treatment of emotional disorders.

Disruption of resting-state functional connectivity of right posterior insula in adolescents and young adults with major depressive disorder

BackgroundThe neural basis of Major Depressive Disorder (MDD) which is a clinical syndrome characterized by emotional and cognitive impairments is poorly understood. Accumulating evidence has suggested that the insula is an important substrate underlying the mechanism of MDD. This study aimed to examine the disrupted resting-state brain regional function in insula and to further investigate the associated resting-state functional connectivity (rs-FC) of insula underlie the MDD in adolescents and young adults. MethodsWe employed 3.0T resting-state functional magnetic resonance imaging (rs-fMRI) to acquire data from 76 adolescents and young adults with MDD and 44 age and sex matched healthy control subjects. We employed a regional Amplitude of Low-Frequency Fluctuation (ALFF) analysis to explore local intrinsic neural oscillation alterations in insula and an ALFF-based functional connectivity (FC) approach to detect the potential changes in remote connectivity with insula in adolescents and young adults with MDD. ResultsBy applying ALFF analysis, significantly decreased activities were detected in bilateral insula, and in particular in right anterior insular gyrus (MNI; ROI1: 42, 24, −3), right posterior insular gyrus (Montreal Neurological Institute, MNI; ROI2: 36, −9, 15) and left anterior insular gyrus (MNI; ROI3: −36, 12, 9) in patients with MDD compared to the healthy controls (p < 0.05, 1000 permutations, TFCE corrected). With ROI2 as the seed in the subsequent ALFF-based rs-FC analysis, patients with MDD were observed to have significantly reduced FC with bilateral middle occipital gyrus, lingual gyrus, calcarine, postcentral gyrus, precentral gyrus, supramarginal area, superior temporal gyrus and middle cingulate gyrus as compared to the healthy controls (p < 0.05, 1000 permutations, TFCE corrected). No significant differences of FC were detected between the patients and healthy controls when using ROI1 and ROI3 as the seeds. We found no correlations between ALFF or rs-FC values and the severity of depression as estimated by Hamilton Depression Rating Scale (HAM-D). LimitationsClinical information were limited and no significant correlations were found between imaging variables and HAM-D scores, which reduces the power to interpret the present findings. A cross-sectional design was employed in this study so that it is not possible to know whether the abnormal ALFF or altered brain FC of insula reflects a state or trait effect in young people with MDD. ConclusionsThis study highlights the regional/network interaction abnormalities of insula in adolescents and young adults with MDD, and could provide further insight into understanding the neural pathomechanism of MDD in young patients.

Brain Structural Magnetic Resonance Imaging for Joint Independent Component Analysis in Schizophrenic Patients.

In past magnetic resonance imaging studies, normal participants and schizophrenia patients have usually been compared using imaging processing modes with only one parameter. A more extensive evaluation of significant differences between gray and white matter in Schizophrenic patents was necessary. Voxel based morphometry was used to separate brain images into gray matter and white matter. Then, the images were mapped to Montreal Neurological Institute space, and DARTEL analytic template was applied for image calibration with statistical parametric mapping. Finally, joint independent component analysis was employed to analyze the gray and white matter of brain images from Schizophrenic patients and normal controls. In this study, joint independent component analysis was used to discriminate clinical differences in magnetic resonance imaging signals between Schizophrenic patients and normal controls. Region of interest analyses has repeatedly shown gray matter reduction in the superior temporal gyrus of Schizophrenic patients. These results strongly support previous studies regarding brain volume in schizophrenic patients. The connection networks in frontal and temporal lobes evidently did not differ between normal participants and schizophrenia patients.

Association of Cortical Stimulation–Induced Seizure With Surgical Outcome in Patients With Focal Drug-Resistant Epilepsy

Cortical stimulation is used during presurgical epilepsy evaluation for functional mapping and for defining the cortical area responsible for seizure generation. Despite wide use of cortical stimulation, the association between cortical stimulation-induced seizures and surgical outcome remains unknown. To assess whether removal of the seizure-onset zone resulting from cortical stimulation is associated with a good surgical outcome. This cohort study used data from 2 tertiary epilepsy centers: Montreal Neurological Institute in Montreal, Quebec, Canada, and Grenoble-Alpes University Hospital in Grenoble, France. Participants included consecutive patients (n = 103) with focal drug-resistant epilepsy who underwent stereoelectroencephalography between January 1, 2007, and January 1, 2017. Participant selection criteria were cortical stimulation during implantation, subsequent open surgical procedure with a follow-up of 1 or more years, and complete neuroimaging data sets for superimposition between intracranial electrodes and the resection. Cortical stimulation-induced typical electroclinical seizures, the volume of the surgical resection, and the percentage of resected electrode contacts inducing a seizure or encompassing the cortical stimulation-informed and spontaneous seizure-onset zones were identified. These measures were correlated with good (Engel class I) and poor (Engel classes II-IV) surgical outcomes. Electroclinical characteristics associated with cortical stimulation-induced seizures were analyzed. In total, 103 patients were included, of whom 54 (52.4%) were female, and the mean (SD) age was 31 (11) years. Fifty-nine patients (57.3%) had cortical stimulation-induced seizures. The percentage of patients with cortical stimulation-induced electroclinical seizures was higher in the good outcome group than in the poor outcome group (31 of 44 [70.5%] vs 28 of 59 [47.5%]; P = .02). The percentage of the resected contacts encompassing the cortical stimulation-informed seizure-onset zone correlated with surgical outcome (median [range] percentage in good vs poor outcome: 63.2% [0%-100%] vs 33.3% [0%-84.6%]; Spearman ρ = 0.38; P = .003). A similar result was observed for spontaneous seizures (median [range] percentage in good vs poor outcome: 57.1% [0%-100%] vs 32.7% [0%-100%]; Spearman ρ = 0.32; P = .002). Longer elapsed time since the most recent seizure was associated with a higher likelihood of inducing seizures (>24 hours: 64.7% vs <24 hours: 27.3%; P = .04). Seizure induction by cortical stimulation appears to identify the epileptic generator as reliably as spontaneous seizures do; this finding might lead to a more time-efficient intracranial presurgical investigation of focal epilepsy as the need to record spontaneous seizures is reduced.

Combined Assessment of Diffusion Parameters and Cerebral Blood Flow Within Basal Ganglia in Early Parkinson's Disease.

Diffusion tensor imaging (DTI) is a sensitive tool for detecting brain tissue microstructural alterations in Parkinson’s disease (PD). Abnormal cerebral perfusion patterns have also been reported in PD patients using arterial spin labeling (ASL) MRI. In this study we aimed to perform a combined DTI and ASL assessment in PD patients within the basal ganglia, in order to test the relationship between microstructural and perfusion alterations. Fifty-two subjects participated in this study. Specifically, 26 PD patients [mean age (SD) = 66.7 (8.9) years, 21 males, median (IQR) Modified Hoehn and Yahr = 1.5 (1–1.6)] and twenty-six healthy controls [HC, mean age (SD) = 65.2 (7.5), 15 males] were scanned with 1.5T MRI. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) maps were derived from diffusion-weighted images, while cerebral blood flow (CBF) maps were computed from ASL data. After registration to Montreal Neurological Institute standard space, FA, MD, AD, RD and CBF median values were extracted within specific regions of interest: substantia nigra, caudate, putamen, globus pallidus, thalamus, red nucleus and subthalamic nucleus. DTI measures and CBF were compared between the two groups. The relationship between diffusion parameters and CBF was tested with Spearman’s correlations. False discovery rate (FDR)-corrected p-values lower than 0.05 were considered significant, while uncorrected p-values <0.05 were considered a trend. No significant FA, MD and RD differences were observed. AD was significantly increased in PD patients compared with HC in the putamen (p = 0.005, pFDR = 0.035). No significant CBF differences were found between PD patients and HC. Diffusion parameters were not significantly correlated with CBF in the HC group, while a significant correlation emerged for PD patients in the caudate nucleus, for all DTI measures (with FA: r = 0.543, pFDR = 0.028; with MD: r = −0.661, pFDR = 0.002; with AD: r = −0.628, pFDR = 0.007; with RD: r = −0.635, pFDR = 0.003). This study showed that DTI is a more sensitive technique than ASL to detect alterations in the basal ganglia in the early phase of PD. Our results suggest that, although DTI and ASL convey different information, a relationship between microstructural integrity and perfusion changes in the caudate may be present.

Increasing body mass index in an elderly cohort: Effects on the quantitative MR parameters of the brain.

Body mass index (BMI) is increasing in a large number of elderly persons. This increase in BMI is known to put one at risk for many "diseases of aging," although less is known about how a change in BMI may affect the brains of the elderly. To investigate the relationship between BMI and quantitative water content, T1 , T2 *, and the semi-quantitative magnetization transfer ratio (MTR) of various structures in elderly brains. Cross-sectional. Forty-two adults (BMI range: 19.1-33.5 kg/m2 , age range: 58-80 years). 3T MRI (two multi-echo gradient echoes, actual flip angle imaging, magnetization prepared rapid gradient echo, fluid attenuated inversion recovery). The 3D two-point method was used to derive (semi-)quantitative parameters in global white (WM) and gray matter (GM) and their regions as defined by the Johns Hopkins University and the Montreal Neurological Institute atlases. Multivariate linear regression with BMI as principal regressor, corrected for the additional regressors age, gender, and glycated hemoglobin. Spearman correlation between quantitative parameters of the regions showing significant changes and the lipid spectra / C-reactive protein (CRP). Voxel-based morphometry and analysis of covariance (ANCOVA) to explore changes in the GM volume. T1 increased significantly (P < 0.05) in the frontal, temporal, and parietal cortices, while the bilateral corona radiata, right superior longitudinal fasciculus, as well as the corpus callosum showed significant changes in the WM regions. T2 * increased significantly in the global WM and left corona radiata. Changes in MTR and the free water content did not reach significance. No significant correlation between any quantitative parameter and the lipid spectra or CRP could be identified. These results suggest that an elevated BMI predominantly affects T1 in WM as well as GM structures in the elderly human brain. 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:514-523.

Topographic Maps of Visual Space in the Human Cerebellum

The purported role of the cerebellum has shifted from one that is exclusively sensorimotor related to one that encompasses a wide range of cognitive and associative functions [1-5]. Within sensorimotor areas of the cerebellum, functional organization is characterized by ipsilateral representations of the body [6]. Yet, in the remaining cerebellar cognitive and associative networks, functional organization remains less well understood. Regions of cerebral cortex [7-9] and subcortex [10] important for visual perception and cognition are organized topographically: neural organization mirrors the retina. Recently, it was shown that known retinotopic areas in cerebral cortex are functionally connected to nodes in the cerebellum [2,11,12]. In fact, this revealed signals with visuospatial selectivity in the cerebellum [13]. Here, we analyzed the highly powered Human Connectome Project (HCP) retinotopy dataset [14] to create a comprehensive and detailed overview of visuospatial organization in the cerebellum. This revealed 5 ipsilateral topographic maps in 3 cerebellar clusters (oculomotor vermis [OMV]-lobule VIIb-lobule VIIIb), of which we quantified visual field coverage and topography. These quantifications dovetail with the known roles of these areas in eye movements (OMV) [5, 15], attention (OMV-VIIb) [5, 13], working memory (VIIb) [13], andthe integration of visuomotor information with respect to effector movements (VIIIb) [5]. To aid future research on visual perception in the cerebellum, we provide an online atlas of the visuospatial maps in Montreal Neurological Institute (MNI) space. Our findings demonstrate that the cerebellum is abundant with visuospatial information and, moreover, that it is organized according to known retinotopic properties.

Arterial Spin Labeling for Glioma Grade Discrimination: Correlations with IDH1 Genotype and 1p/19q Status

Since accurate grading of gliomas has important clinical value, the aim of this study is to evaluate the diagnostic efficacy of perfusion values derived from arterial spin labeling (ASL) to grade gliomas. In addition, the correlation between perfusion and isocitrate dehydrogenase 1 (IDH1) genotypes and chromosome arms 1p and 19q (1p/19q) status of gliomas was assessed. A total of 52 cases of supratentorial gliomas in adults who received ASL imaging were enrolled in this retrospective study. The cerebral blood flow (CBF) images derived from ASL and anatomical maps were normalized to the Montreal Neurological Institute coordinate system and matched. The mean CBF (meanCBF), the maximum CBF (maxCBF), and their relative values (rmeanCBF and rmaxCBF, respectively) were assessed in each case. The tumor grades, IDH1 genotypes, and 1p/19q status were diagnosed according to the 2016 WHO criteria. Receiver operating characteristic curves were performed to assess the efficacy of perfusion parameters for grading. Qualitatively, all gliomas were divided into high- and low-perfusion groups. The crosstabs chi-square test of independence was performed to calculate contingency coefficient (C) and Cramer V coefficient to assess the correlation between perfusion and IDH1 genotypes and 1p/19q status of gliomas. The rmaxCBF showed the best diagnostic efficacy; meanwhile, rmeanCBF had the best specificity for grade discrimination. In astrocytoma, there was a mild correlation between IDH1 genotypes and tumor perfusion with the Cramer's V coefficient of 0.378. There was no significant association between 1p/19q codeletion and perfusion in grade II and III gliomas.

Analysis of Contact Position for Subthalamic Nucleus Deep Brain Stimulation-Induced Hyperhidrosis.

Objectives To analyze the hyperhidrosis neural network structure induced by subthalamic nucleus (STN) - deep brain stimulation (DBS). Materials and Methods Patients with Parkinson's disease treated with STN-DBS in Changhai Hospital between July 1, 2015, and December 1, 2016, were analyzed retrospectively. Using records of side effects of the intraoperative macrostimulation test, patients with skin sweats were selected as the sweating group. Based on the number of cases in the sweating group, the same number of patients was randomly selected from other STN-DBS patients without sweating to form the control group. The study standardized electrode position with Lead-DBS software to Montreal Neurological Institute (MNI) standard stereotactic space to compare the differences in three-dimensional coordinates of activated contacts between groups. Results Of 355 patients, 11 patients had sweats during intraoperative macrostimulation tests. There was no significant difference in the preoperative baseline information and the postoperative UPDRS-III improvement rate (Med-off, IPG-on) between groups. Contacts inducing sweat were more medial (X-axis) (11.02 ± 0.69 mm vs 11.98 ± 0.84 mm, P=0.00057) and more upward (Z-axis) (−7.15 ± 1.06 mm VS −7.98 ± 1.21 mm, P=0.032) than those of the control group. The straight-line distance between the center of the sweat contact and the nearest voxel of the red nucleus was closer than that of the control group (2.72 ± 0.65 mm VS 3.76 ± 0.85 mm, P=0.00012). Conclusions STN-DBS-induced sweat indicated that the contact was at superior medial of STN.

Brenda Milner: 100 Years from The Birthday

Brenda Milner is a renowned British-Canadian neuropsychologist known as «the founder of neuropsychology». She was born about 100 years ago, and as a Cambridge graduate, she started her research carreer of a neurobiologist and psychologist in 1940s. Her comprehensive contribution to the development of clinical neuropsychology thereafter was marked by several awards including the Balzan Prize for Cognitive Neuroscience in 2009 and the Kavli Prize in Neuroscience in 2014 (shared with Marcus Raichle and John O'Keefe), as well as memberships in the Royal Society of London, the Royal Society of Canada and the National Academy of Sciences. She holds more than 20 honorary degrees at universities across Europe, Canada and the USA. Currently, Brenda Milner keeps working as a professor in the Department of Neurology and Neurosurgery at McGill University (Montreal, Canada) and a professor of Psychology at the Montreal Neurological Institute with her research mainly focused on the inter-hemispheric interactions. One of important contributions in neuropsychology by Brenda Milner was brought to the study of mechanisms of memory worsening in elderly. Due to the fact that most diseases associated with aging are characterized by memory disorders, this topic finds its high importance in the studies of gerontology. Working with patients who suffered the brain lobes removal, Brenda Milner received many new data on the complex and hierarchical organization of memory mechanisms in the brain. A unique case of an 86-year-old patient M.P. showed the brain changes due to lobectomy to remain stable for dozens of years. Neuropsychological methods have shown that in her 86 years, the patient with lobectomy was in no way inferior to her peers. Minor violations of verbal memory have been preserved throughout life without any deterioration. This long-term and rather interesting study is described in detail in the present article.