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BackgroundConventionally, transcranial direct current stimulation (tDCS) aims to focalize the current reaching the target region-of-interest (ROI). The focality can be quantified by the dose-target-determination-index (DTDI). Despite having a uniform tDCS setup, some individuals receive focal stimulation (high DTDI) while others show reduced focality (“non-focal”). The volume of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) underlying each ROI govern the tDCS current distribution inside the brain, thereby regulating focality.AimTo determine the regional volume parameters that differentiate the focal and non-focal groups.MethodsT1-weighted images of the brain from 300 age-sex matched adults were divided into three equal groups- (a) Young (20 ≤ × < 40 years), (b) Middle (40 ≤ × < 60 years), and (c) Older (60 ≤ × < 80 years). For each group, inter and intra-hemispheric montages with electrodes at (1) F3 and right supraorbital region (F3-RSO), and (2) CP5 and Cz (CP5-Cz) were simulated, targeting the left- Dorsolateral Prefrontal Cortex (DLPFC) and -Inferior Parietal Lobule (IPL), respectively. Both montages were simulated for two current doses (1 and 2 mA). For each individual head simulated for a tDCS configuration (montage and dose), the current density at each region-of-interest (ROI) and their DTDI were calculated. The individuals were categorized into two groups- (1) Focal (DTDI ≥ 0.75), and (2) Non-focal (DTDI < 0.75). The regional volume of CSF, GM, and WM of all the ROIs was determined. For each tDCS configuration and ROI, three 3-way analysis of variance was performed considering- (i) GM, (ii) WM, and (iii) CSF as the dependent variable (DV). The age group, sex, and focality group were the between-subject factors. For a given ROI, if any of the 3 DV’s showed a significant main effect or interaction involving the focality group, then that ROI was classified as a “focal ROI.”ResultsRegional CSF was the principal determinant of focality. For interhemispheric F3-RSO montage, interaction effect (p < 0.05) of age and focality was observed at Left Caudate Nucleus, with the focal group exhibiting higher CSF volume. The CSF volume of focal ROI correlated positively (r ∼ 0.16, p < 0.05) with the current density at the target ROI (DLPFC). For intrahemispheric CP5-Cz montage, a significant (p < 0.05) main effect was observed at the left pre- and post-central gyrus, with the focal group showing lower CSF volume. The CSF volume correlated negatively (r ∼ –0.16, p < 0.05) with current density at left IPL. The results were consistent for both current doses.ConclusionThe CSF channels the flow of tDCS current between electrodes with focal ROIs acting like reservoirs of current. The position of focal ROI in the channel determines the stimulation intensity at the target ROI. For focal stimulation in interhemispheric F3-RSO, the proximity of focal ROI reserves the current density at the target ROI (DLPFC). In contrast, for intrahemispheric montage (CP5-Cz), the far-end location of focal ROI reduces the current density at the target (IPL).

[Objective] We aim to establish a diagnostic system for progressive supranuclear palsy (PSP) by tau positron emission tomography (PET) with 18F-PM-PBB3. [Methods] We employed the data of 24 healthy controls (HC; age 67.5 ± 5.1 [mean ± SD] y, 9 males); 30 PSP (71.4 ± 8.2 y, 21 males, PSP rating scale [PSPRS] 41.1 ± 17.7) who met the MDS-PSP criteria and showed a typical topological pattern of 18F-PM-PBB3 PET observed in PSP. All data were corrected by age and sex, and standardized for analysis. Standardized uptake value ratios using the cerebellar cortex as reference region were obtained in 112 volumes of interests (VOIs) by the multi-atlas method. The Elastic Net cross validation analysis was applied to the set of VOIs to determine which VOIs useful for discriminating PSP from HC. The obtained coefficients were applied to each individual data to calculate and define as PSP score. We tested PSP score for validation to 10 HC (68.9 ± 7.4 y, 7 males) and 5 PSP cases (73.0 ± 7.8 y, 3 males, PSPRS 46.6 ± 11.3) in a new cohort. We also evaluated association between PSP score and disease severity measured by PSPRS. [Results] Globus pallidus, putamen and midbrain were selected as pivotal VOIs calculating PSP score. PSP score for training and validation data showed accuracy of 94.4% and 80%, precision of 93.3% and 100%, and recall of 96.6% and 62.5%. Moreover, PSPRS correlated well with PSP score (Spearman’s rs = 0.56, p < 0.001). [Conclusions] Automated analysis system of tau PET with 18F-PM-PBB3 would be a promising tool both for diagnosing and predicting disease severity in PSP., 第62回日本神経学会学術大会

Advances in magnetic resonance imaging (MRI) and computational analysis technology have enabled comparisons among various primate brains in a three-dimensional electronic format. Results from comparative studies provide information about common features across primates and species-specific features of neuroanatomy. Investigation of various species of non-human primates is important for understanding such features, but the majority of comparative MRI studies have been based on experimental primates, such as common marmoset, macaques, and chimpanzee. A major obstacle has been the lack of a database that includes non-experimental primates’ brain MRIs. To facilitate scientific discoveries in the field of comparative neuroanatomy and brain evolution, we launched a collaborative project to develop an open-resource repository of non-human primate brain images obtained using ex vivo MRI. As an initial open resource, here we release a collection of structural MRI and diffusion tensor images obtained from 12 species: pygmy marmoset, owl monkey, white-fronted capuchin, crab-eating macaque, Japanese macaque, bonnet macaque, toque macaque, Sykes’ monkey, red-tailed monkey, Schmidt’s guenon, de Brazza’s guenon, and lar gibbon. Sixteen postmortem brain samples from the 12 species, stored in the Japan Monkey Centre (JMC), were scanned using a 9.4-T MRI scanner and made available through the JMC collaborative research program (http://www.j-monkey.jp/BIR/index_e.html). The expected significant contributions of the JMC Primates Brain Imaging Repository include (1) resources for comparative neuroscience research, (2) preservation of various primate brains, including those of endangered species, in a permanent digital form, (3) resources with higher resolution for identifying neuroanatomical features, compared to previous MRI atlases, (4) resources for optimizing methods of scanning large fixed brains, and (5) references for veterinary neuroradiology. User-initiated research projects beyond these contributions are also anticipated.

Background and Purpose: Measuring head circumference (HC) in infants is an easy screening procedure with which to detect abnormalities in brain growth. It has been demonstrated that HC can predict total brain volume (TBV) in very-low-birth-weight (VLBW) infants. However, the correlation between HC and TBV was weaker than that observed in healthy term-born toddlers, suggesting that there are factors that influence the relationship between HC and TBV. The aim of this study was to identify the clinical risk factors that caused a deviation from the regression line obtained between HC and TBV. Methods: The study population was based on 37 VLBW infants, who underwent a clinical MRI examination at a term-equivalent age, during 2013 - – 2015, at Toyama University Hospital. The HC and the TBV were both adjusted for sex, multiple births, and postmenstrual age. The relationship between TBV/HC and clinical characteristics was evaluated. Results: There was a positive correlation between HC and TBV (r = 0.58, p = 0.000168). Two clinical factors, the lower birth body weight (BBW) (r=0.38, p=0.02) and dolichocephaly (r = 0.46, p=0.006), were identified as factors that negatively affected the TBV/HC ratio. After excluding infants with low BBW or with dolichocephaly, the correlation between HC and TBV was higher (r = 0.63). Conclusions: Although HC has predictive value for TBV in VLBW infants, care should be taken in infants with low BBW (BBW less than 600 g) or dolichocephaly (MRI-based Cranial Index less than 0.68), which were related to overestimation of TBV.

Analysis of descriptions of the “Cookie Theft” picture from the Boston Diagnostic Aphasia Examination have been shown to (1) distinguish between controls, and chronic mild, moderate, and severe aphasia(Craig et al., 1993; Yorkston & Beukelman, 1980); and (2) distinguish distinct profiles of deficits in chronic right hemisphere (RH) stroke (Myers, 1978; Trupe & Hillis, 1985). We hypothesized that analysis of the “Cookie Theft” picture descriptions in acute stroke would also: (1) provide quantitative measures of severity of communication impairment that correlate with volume of infarct or volume of lesion in key regions of interest; and (2) provide quantitative measures of hemispatial attention that distinguish RH from left hemisphere (LH) stroke and from controls. Methods: We analyzed picture descriptions of patients with acute ischemic LH (n=28), RH (n=25) stroke, and healthy controls (n=25) for total content units (CU) produced by previously studied healthy controls during picture descriptions (Yorkston & Beukelman, 1980), syllables/CU, and ratio of left page:right page CU (LCU:RCU). CUs defined as nouns, adjective, and verbs relevant to the picture. Diffusion-weighted images were registered to a common atlas, to measure volume of infarct and percent damage to regions of interest without knowledge of behavioral analysis. We evaluated differences across groups with ANOVA and across pairs of groups with t-tests. We evaluated correlations between each measure and volume of infarct and percent damage to 6 cortical and 3 white matter regions of interest in each hemisphere (inferior frontal gyrus, superior temporal gyrus, middle temporal gyrus, fusiform gyrus, angular gyrus, and supramarginal gyrus; superior fronto-occipital fasciculus, superior longitudinal fasciculus, and sagittal stratum) with Pearson correlations. Results: There were no differences between groups in age, education, or sex distribution. LH and RH patients produced fewer CU (p

The fornix is the predominant outflow tract of the hippocampus, a brain region known to be affected early in the course of Alzheimer's disease (AD). The aims of the present study were to: (1) examine the cross-sectional relationship between fornix diffusion tensor imaging (DTI) measurements (fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity, and radial diffusivity), hippocampal volume, and memory performance, and (2) compare fornix DTI measures with hippocampal volumes as predictors of progression and transition from amnestic mild cognitive impairment to AD dementia.Twenty-three mild cognitive impairment participants for whom hippocampal volumetry and DTI were conducted at baseline received detailed evaluations at baseline; 3, 6, and 12 months; and 2.5 years. Six participants converted to AD over the follow-up period. Fornix and posterior cingulum DTI measurements and hippocampal volumes were ascertained using manual measures. Random effects models assessed each of the neuroimaging measures as predictors of decline on the Mini-Mental State Examination, Clinical Dementia Rating-sum of boxes, and memory z scores; receiver operating characteristic analyses examined the predictive value for conversion to AD.There was a significant correlation between fornix FA and hippocampal volumes. However, only the fornix measurements (FA, MD, radial diffusivity, and axial diffusivity) were cross-sectionally correlated with memory z scores. Both fornix FA and hippocampal volumes were predictive of memory decline. Individually, fornix FA and MD and hippocampal volumes were very good predictors of progression, with likelihood ratios83, and better than 90% accuracy.Fornix FA both cross-sectionally correlated with and longitudinally predicted memory decline and progression to AD. Manually drawn region of interest within the fornix shows promise comparable with hippocampal volume as a predictive biomarker of progression, and this finding warrants replication in a larger study.