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AIM: While conservatism bias refers to the human need for more evidence for decision-making than rational thinking expects, the jumping to conclusions (JTC) bias refers to the need for less evidence among individuals with schizophrenia/delusion compared to healthy people. Although the hippocampus-midbrain-striatal aberrant salience system and the salience, default mode (DMN), and frontoparietal networks ("triple networks") are implicated in delusion/schizophrenia pathophysiology, the associations between conservatism/JTC and these systems/networks are unclear. METHODS: Thirty-seven patients with schizophrenia and 33 healthy controls performed the beads task, with large and small numbers of bead draws to decision (DTD) indicating conservatism and JTC, respectively. We performed independent component analysis (ICA) of resting functional magnetic resonance imaging (fMRI) data. For systems/networks above, we investigated interactions between diagnosis and DTD, and main effects of DTD. We similarly applied ICA to structural and diffusion MRI to explore the associations between DTD and gray/white matter. RESULTS: We identified a significant main effect of DTD with functional connectivity between the striatum and DMN, which was negatively correlated with delusion severity in patients, indicating that the greater the anti-correlation between these networks, the stronger the JTC and delusion. We further observed the main effects of DTD on a gray matter network resembling the DMN, and a white matter network connecting the functional and gray matter networks (all P < 0.05, family-wise error [FWE] correction). Function and gray/white matter showed no significant interactions. CONCLUSION: Our results support the novel association of conservatism and JTC biases with aberrant salience and default brain mode.
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Tomada de Decisões , Rede de Modo Padrão , Delusões , Imageamento por Ressonância Magnética , Esquizofrenia , Humanos , Adulto , Rede de Modo Padrão/fisiopatologia , Rede de Modo Padrão/diagnóstico por imagem , Masculino , Feminino , Esquizofrenia/fisiopatologia , Esquizofrenia/diagnóstico por imagem , Delusões/fisiopatologia , Delusões/diagnóstico por imagem , Tomada de Decisões/fisiologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Substância Branca/diagnóstico por imagem , Substância Branca/fisiopatologia , Substância Branca/patologia , Pessoa de Meia-Idade , Adulto Jovem , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/fisiopatologia , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/fisiopatologia , Substância Cinzenta/patologiaRESUMO
Neuroimaging databases for neuro-psychiatric disorders enable researchers to implement data-driven research approaches by providing access to rich data that can be used to study disease, build and validate machine learning models, and even redefine disease spectra. The importance of sharing large, multi-center, multi-disorder databases has gradually been recognized in order to truly translate brain imaging knowledge into real-world clinical practice. Here, we review MRI databases that share data globally to serve multiple psychiatric or neurological disorders. We found 42 datasets consisting of 23,293 samples from patients with psychiatry and neurological disorders and healthy controls; 1245 samples from mood disorders (major depressive disorder and bipolar disorder), 2015 samples from developmental disorders (autism spectrum disorder, attention-deficit hyperactivity disorder), 675 samples from schizophrenia, 1194 samples from Parkinson's disease, 5865 samples from dementia (including Alzheimer's disease), We recognize that large, multi-center databases should include governance processes that allow data to be shared across national boundaries. Addressing technical and regulatory issues of existing databases can lead to better design and implementation and improve data access for the research community. The current trend toward the development of shareable MRI databases will contribute to a better understanding of the pathophysiology, diagnosis and assessment, and development of early interventions for neuropsychiatric disorders.
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OBJECTIVE: The motor severity in Parkinson disease (PD) is believed to parallel dopaminergic terminal degeneration in the striatum, although the terminal was reported to be virtually absent by 4 years postdiagnosis. Meanwhile, neuromelanin-laden dopamine neuron loss in the substantia nigra (SN) elucidated a variability at early stages and gradual loss with less variability 10 years postdiagnosis. Here, we aimed to clarify the correlation between motor impairments and striatal dopaminergic terminal degeneration and nigral neuromelanin-laden dopamine neuron loss at early to advanced stages of PD. METHODS: Ninety-three PD patients were divided into early and advanced subgroups based on motor symptom duration and whether motor fluctuation was present. Striatal dopaminergic terminal degeneration was evaluated using a presynaptic dopamine transporter tracer, 123 I-ioflupane single photon emission computed tomography (SPECT). Nigral neuromelanin-laden dopamine neuron density was assessed by neuromelanin-sensitive magnetic resonance imaging (NM-MRI). RESULTS: In patients with early stage PD (motor symptoms for ≤8 or 10 years), motor dysfunction during the drug-off state was paralleled by a decline in 123 I-ioflupane uptake in the striatum despite the absence of a correlation with reductions in NM-MRI signals in SN. Meanwhile, in patients with advanced stage PD (motor symptoms for >8 or 10 years and with fluctuation), the degree of motor deficits during the drug-off state was not correlated with 123 I-ioflupane uptake in the striatum, despite its significant negative correlation with NM-MRI signals in SN. INTERPRETATION: We propose striatal dopaminergic terminal loss measured using 123 I-ioflupane SPECT and nigral dopamine neuron loss assessed with NM-MRI as early stage and advanced stage motor impairment biomarkers, respectively. ANN NEUROL 2022;92:110-121.
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Doença de Parkinson , Corpo Estriado/metabolismo , Dopamina , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Neurônios Dopaminérgicos/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Degeneração Neural/diagnóstico por imagem , Degeneração Neural/patologia , Doença de Parkinson/complicações , Doença de Parkinson/diagnóstico por imagem , Substância Negra/patologia , Tomografia Computadorizada de Emissão de Fóton Único/métodosRESUMO
OBJECTIVES: Neuropsychiatric symptom could be useful for detecting patients with prodromal dementia. Similarities and differences in the NPSs between preclinical/prodromal Alzheimer's disease (AD) and prodromal Parkinson's disease dementia (PDD)/Dementia with Lewy bodies (DLB) may exist. This study aimed to compare the NPSs between preclinical/prodromal AD and prodromal PDD/DLB. METHODS: One hundred and three participants without dementia aged ≥50 years were included in this study. The mild behavioral impairment (MBI) total score and the MBI scores for each domain were calculated using the neuropsychiatric inventory questionnaire score. Participants were divided into five groups based on the clinical diagnosis by neurologists or psychiatrists in each institution based on the results of the amyloid positron emission tomography and dopamine transporter single photon emission computed tomography (DAT-SPECT): Group 1: amyloid-positive and abnormal DAT-SPECT, Group 2: amyloid-negative and abnormal DAT-SPECT, Group 3: amyloid-positive and normal DAT-SPECT, Group 4: mild cognitive impairment unlikely due to AD with normal DAT-SPECT, and Group 5: cognitively normal with amyloid-negative and normal DAT-SPECT. RESULTS: The MBI abnormal perception or thought content scores were significantly higher in Group 1 than Group 5 (Bonferroni-corrected p = 0.012). The MBI total score (Bonferroni-corrected p = 0.011) and MBI impulse dyscontrol score (Bonferroni-corrected p = 0.033) in Group 4 were significantly higher than those in Group 5. CONCLUSION: The presence of both amyloid and putative Lewy body pathologies may be associated with psychotic symptoms.
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Doença de Alzheimer , Disfunção Cognitiva , Demência , Doença de Parkinson , Humanos , Corpos de Lewy , Doença de Alzheimer/diagnóstico por imagemRESUMO
PURPOSE: To demonstrate the capability of insertable inductively coupled volumetric coils for MR microscopy in a human 7T MR system. METHODS: Insertable inductively coupled volume coils with diameters of 26 and 64 mm (D26 and D64 coils) targeted for monkey and mouse brain specimen sizes were designed and fabricated. These coils were placed inside the imaging volume of a transmit/receive knee coil without wired connections to the main system. Signal-to-noise ratio (SNR) evaluations were conducted with and without the insertable coils, and the g-factor maps of parallel imaging (PI) were also calculated for the D64 coil. Brain specimens were imaged using 3D T2∗ -weighted images with spatial resolution of isotropic 50 and 160 µm using D26 and D64 coils, respectively. RESULTS: Relative average (SD) SNRs compared with knee coil alone were 12.54 (0.30) and 2.37 (0.05) at the center for the D26 and D64 coils, respectively. The mean g-factors of PI with the D64 coil for the factor of 2 were less than 1.1 in the left-right and anterior-posterior directions, and around 1.5 in the superior-inferior direction or when the PI factor of 3 was used. Acceleration in two directions showed lower g-factors but suffered from intrinsic low SNR. Representative T2∗ -weighted images of the specimen showed structural details. CONCLUSION: Inductively coupled small diameter coils insertable to the knee coil demonstrated high SNR and modest PI capability. The concept was successfully used to visualize fine structures of the brain specimen. The insertable coils are easy to handle and enable MR microscopy in a human whole-body 7T MRI system.
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Imageamento por Ressonância Magnética , Microscopia , Animais , Encéfalo/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Camundongos , Imagens de Fantasmas , Razão Sinal-RuídoRESUMO
BACKGROUND: In deep brain stimulation (DBS) for Parkinson's disease (PD), the clinical outcome largely depends on the appropriate position of the electrode implanted in the targeted structure. In intraoperative cone-beam computed tomography (CT) performed for the evaluation of the electrode position, the metal artifact induced by the implanted electrode can prevent the precise localization of the electrode. Metal artifact reduction (MAR) techniques have been recently developed that can dramatically improve the visualization of objects by reducing metal artifacts after performing cone-beam CT. Hence, in this case series, we attempted to clarify the usefulness and accuracy of intraoperative cone-beam CT with MAR (intraCBCTwM) by comparing with both intraoperative cone-beam CT without MAR (intraCBCTwoM) and conventional postoperative CT (post-CT) for the assessment of the implanted electrode position and the intracranial structures during DBS procedures. METHODS: Between November 2019 and December 2020, 10 patients with PD who underwent DBS at our institution were recruited, and the images of 9 patients (bilateral: n = 8, unilateral: n = 1) were analyzed. The artifact index (AI) in intraCBCTwM or intraCBCTwoM, and conventional post-CT were retrospectively assessed using the standard deviation of the region-of-interest around the implanted electrodes and background noise. Additionally, the Euclidean distances gap of electrode tip based on post-CT in each fusion image was compared between intraCBCTwM and intraCBCTwoM. RESULTS: The AI was significantly lower in intraCBCTwM than in intraCBCTwoM (P < 0.01). The mean Euclidean distance between the tip of the electrode in intraCBCTwM and in post-CT was significantly shorter compared to that in intraCBCTwoM (P < 0.05). CONCLUSIONS: The results reported here suggest that intraCBCTwM is a more useful and accurate method than intraCBCTwoM to assess the implanted electrode position and intracranial structures during DBS.
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Estimulação Encefálica Profunda , Doença de Parkinson , Artefatos , Tomografia Computadorizada de Feixe Cônico/métodos , Estimulação Encefálica Profunda/métodos , Eletrodos Implantados , Humanos , Doença de Parkinson/cirurgia , Doença de Parkinson/terapia , Estudos RetrospectivosRESUMO
BACKGROUND: Neuromelanin-sensitive magnetic resonance imaging techniques have been developed but currently require relatively long scan times. The aim of this study was to assess the ability of black-blood delay alternating with nutation for tailored excitation-prepared T1-weighted variable flip angle turbo spin echo (DANTE T1-SPACE), which provides relatively high resolution with a short scan time, to visualize neuromelanin in the substantia nigra pars compacta (SNpc). METHODS: Participants comprised 49 healthy controls and 25 patients with Parkinson's disease (PD). Contrast ratios of SNpc and hyperintense SNpc areas, which show pixels brighter than thresholds, were assessed between DANTE T1-SPACE and T1-SPACE in healthy controls. To evaluate the diagnostic ability of DANTE T1-SPACE, the contrast ratios and hyperintense areas were compared between healthy and PD groups, and receiver operating characteristic analyses were performed. We also compared areas under the curve (AUCs) between DANTE T1-SPACE and the previously reported gradient echo neuromelanin (GRE-NM) imaging. Each analysis was performed using original images in native space and images transformed into Montreal Neurological Institute space. Values of P < 0.05 were considered significant. RESULTS: DANTE T1-SPACE showed significantly higher contrast ratios and larger hyperintense areas than T1-SPACE. On DANTE T1-SPACE, healthy controls showed significantly higher contrast ratios and larger hyperintense areas than patients with PD. Hyperintense areas in native space analysis achieved the best AUC (0.94). DANTE T1-SPACE showed AUCs as high as those of GRE-NM. CONCLUSIONS: DANTE T1-SPACE successfully visualized neuromelanin of the SNpc and showed potential for evaluating PD. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Melaninas , Doença de Parkinson , Humanos , Imageamento por Ressonância Magnética , Doença de Parkinson/diagnóstico por imagem , Parte Compacta da Substância Negra , Substância NegraRESUMO
In the pharmacotherapy of patients with Parkinson's disease (PD), entacapone reduces the peripheral metabolism of L-dopa to 3-O-methyldopa (3-OMD), thereby prolonging the half-life (t1/2) of L-dopa and increasing the area under the concentration curve (AUC). The effect of entacapone on the pharmacokinetics of L-dopa differs between patients with high-activity (H/H) and low-activity (L/L) catechol-O-methyltransferase (COMT) Val158Met polymorphisms, but the effects are unclear in heterozygous (H/L) patients. 3-OMD has a detrimental effect and results in a poor response to L-dopa treatment in patients with PD; however, the influence of this polymorphism on the production of 3-OMD remains unknown. Therefore, the present study aimed to clarify the effect of the COMT Val158Met polymorphism on the concentrations of L-dopa and 3-OMD in the presence of entacapone. We performed an open-label, single-period, single-sequence crossover study at two sites in Japan. The study included 54 Japanese patients with PD, who underwent an acute L-dopa administration test with and without 100 mg entacapone on two different days. Entacapone increased L-dopa AUC0-infinity by 1.59 ± 0.26-fold in the H/H group, which was significantly higher than that in the H/L (1.41 ± 0.36-fold) and L/L (1.28 ± 0.21-fold) groups (p < 0.05). The concurrent administration of L-dopa with entacapone suppressed the increase in 3-OMD levels compared with L-dopa alone in all genotypes. Our results suggest that the COMT Val158Met polymorphism may be an informative biomarker for individualized dose adjustment of COMT inhibitors in the treatment of PD.
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Catecol O-Metiltransferase , Levodopa , Antiparkinsonianos , Catecol O-Metiltransferase/genética , Inibidores de Catecol O-Metiltransferase , Catecóis , Estudos Cross-Over , Humanos , Nitrilas , Tirosina/análogos & derivadosRESUMO
This article reviews the stereotactic targets in the posterior subthalamic area(PSA), fields H1/H2 of Forel(pallidothalamic tract), and the pedunculopontine nucleus(PPN)to complement the preceding articles on stereotactic and functional neurosurgery for movement disorders in the present issue of No Shinkei Geka. Two regions within the subthalamus, the PSA and fields H1/H2 of Forel, are the revisited stereotactic targets to treat movement disorders. Currently, the PSA is often utilized to treat essential tremor and various types of tremor. Fields H1/H2 of Forel are investigated as a target for magnetic resonance-guided focused ultrasound to treat motor symptoms and motor complications in patients with Parkinson's disease. For the past twenty years, the PPN has been investigated to treat refractory gait freezing and fall in patients with Parkinson's disease. These revisited and novel targets may be utilized as substitutes and complements for the present standard stereotactic targets.
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Estimulação Encefálica Profunda , Tremor Essencial , Doença de Parkinson , Tremor Essencial/terapia , Humanos , Imageamento por Ressonância Magnética , Doença de Parkinson/terapia , TremorRESUMO
Background Quantitative susceptibility mapping (QSM) is used to differentiate between calcification and iron deposits. Few studies have examined the relationship between CT attenuation values and magnetic susceptibility in such materials. Purpose To assess the relationship among metal concentration, CT attenuation values, and magnetic susceptibility in paramagnetic and diamagnetic phantoms, and the relationship between CT attenuation values and susceptibility in brain structures that have paramagnetic or diamagnetic properties. Materials and Methods In this retrospective study, CT and MRI with QSM were performed in gadolinium and calcium phantoms, patients, and healthy volunteers between June 2016 and September 2017. In the phantom study, we evaluated correlations among metal concentration, CT attenuation values, and susceptibility. In the human study, Pearson and Spearman correlations were performed to assess the relationship between CT attenuation values and susceptibility in regions of interest placed in the globus pallidus (GP), putamen, caudate nucleus, substantia nigra, red nucleus, dentate nucleus, choroid plexus, and hemorrhagic and calcified lesions. Results Eighty-four patients (mean age, 64.8 years ± 19.6; 49 women) and 20 healthy volunteers (mean age, 72.0 years ± 7.6; 11 men) were evaluated. In the phantoms, strong linear correlations were identified between gadolinium concentration and CT and MRI QSM values (Râ2 = 0.95 and 0.99, respectively; P < .001 for both) and between calcium concentration and CT and MRI QSM values (Râ2 = 0.89 [P = .005] and Râ2 = 0.98 [P < .001], respectively). In human studies, positive correlations between CT attenuation values and susceptibility were observed in the GP (Râ2 = 0.52, P < .001) and in hemorrhagic lesions (Râ2 = 0.38, P < .001), and negative correlations were found in the choroid plexus (Râ2 = 0.53, P < .001) and in calcified lesions (Râ2 = 0.38, P = .009). Conclusion CT attenuation values showed a positive correlation with susceptibility in the globus pallidus and hemorrhagic lesions and negative correlation in the choroid plexus and calcified lesions. © RSNA, 2020 Online supplemental material is available for this article.
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Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Encefalopatias/diagnóstico por imagem , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Estudos RetrospectivosRESUMO
INTRODUCTION: Myopathy associated with anti-mitochondrial antibody (AMA) has recently been characterized as a distinct type of idiopathic inflammatory myopathy. The purpose of this study is to evaluate the pattern of involvement in thigh muscles in AMA myopathy using MRI. METHODS: Six patients with AMA myopathy were identified and their muscle MRI findings evaluated. RESULTS: On thigh muscle MRI, all six patients showed high signal intensity with short-tau inversion recovery that reflected disease activity mostly in the adductor magnus, called a "cuneiform sign." Fatty degeneration was also prominent in the adductor magnus, as well as the semimembranosus muscles. DISCUSSION: These characteristic changes on MRI contrast with those of other inflammatory myopathies. From these observations, we concluded that the localization pattern of the inflammatory changes in muscle MRI can contribute to the diagnosis of AMA myopathy.
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Autoanticorpos/imunologia , Doenças Autoimunes/complicações , Doenças Autoimunes/diagnóstico por imagem , Mitocôndrias Musculares/imunologia , Miopatias Mitocondriais/diagnóstico por imagem , Miopatias Mitocondriais/etiologia , Músculo Esquelético/diagnóstico por imagem , Coxa da Perna/diagnóstico por imagem , Tecido Adiposo/patologia , Adulto , Idoso , Atrofia , Feminino , Granuloma/patologia , Humanos , Hipertrofia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Coxa da Perna/patologiaRESUMO
Axonal Charcot-Marie-Tooth disease (CMT) is most frequently caused by mutations in the MFN2 gene (CMT2A) that can lead to various clinical phenotypes. The age at disease onset varies, but most cases occur before adolescence. We report two Japanese sisters who presented with middle-age-onset peripheral neuropathy with distinct clinical features. In the affected sisters, a homozygous missense mutation, c.1894C>T, p.R632W, corresponding to the transmembrane domain of MFN2 was identified; this mutation was heterozygous in another non-affected sibling, demonstrating co-segregation of the genotype and phenotype. The patients developed adult-onset slowly progressive muscle weakness that was predominant in the calf muscles and sensory disturbance. Magnetic resonance imaging revealed diffuse atrophy of the spinal cord, especially in the thoracic segment, and mild atrophy of the parietal lobe and the cerebellum in both patients. Electron microscopy of the sural nerve revealed clusters of round and swollen mitochondria. This is the first case report of adult-onset CMT2A with an autosomal-recessive inheritance pattern. The phenotype caused by the MFN2 mutation in these cases is very mild, considering that the mutation causes middle-aged-onset Charcot-Marie-Tooth even in the homozygous state. The mechanism of MFN2 mutation-induced toxicity is an interesting theme that awaits further investigations.
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Doença de Charcot-Marie-Tooth/genética , GTP Fosfo-Hidrolases/genética , Genes Recessivos , Proteínas Mitocondriais/genética , Mutação de Sentido Incorreto , Adulto , Idade de Início , Doença de Charcot-Marie-Tooth/patologia , Feminino , HumanosRESUMO
In order to preserve postoperative language function, we recently proposed a new intraoperative method to monitor the integrity of the dorsal language pathway (arcuate fasciculus; AF) using cortico-cortical evoked potentials (CCEPs). Based on further investigations (20 patients, 21 CCEP investigations), including patients who were not suitable for awake surgery (five CCEP investigations) or those without preoperative neuroimaging data (eight CCEP investigations including four with untraceable tractography due to brain edema), we attempted to clarify the clinical impact of this new intraoperative method. We monitored the integrity of AF by stimulating the anterior perisylvian language area (AL) by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. After tumor resection, single-pulse electrical stimuli were also applied to the floor of the removal cavity to record subcortico-cortical evoked potentials (SCEPs) at AL and PL in 12 patients (12 SCEP investigations). We demonstrated that (1) intraoperative dorsal language network monitoring was feasible even when patients were not suitable for awake surgery or without preoperative neuroimaging studies, (2) CCEP is a dynamic marker of functional connectivity or integrity of AF, and CCEP N1 amplitude could even become larger after reduction of brain edema, (3) a 50% CCEP N1 amplitude decline might be a cut-off value to prevent permanent language dysfunction due to impairment of AF, (4) a correspondence (<2.0 ms difference) of N1 onset latencies between CCEP and the sum of SCEPs indicates close proximity of the subcortical stimulus site to AF (<3.0 mm). Hum Brain Mapp 38:1977-1991, 2017. © 2017 Wiley Periodicals, Inc.
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Mapeamento Encefálico , Córtex Cerebral/fisiopatologia , Eletrocorticografia/métodos , Potenciais Evocados/fisiologia , Idioma , Substância Branca/fisiopatologia , Adulto , Idoso , Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/cirurgia , Estimulação Elétrica , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Tempo de Reação , Estudos Retrospectivos , Vigília , Substância Branca/diagnóstico por imagem , Adulto JovemRESUMO
BACKGROUND: Cerebral amyloid angiopathy (CAA) is classified as type 1 with capillary amyloid ß (Aß) or type 2 without capillary Aß. While it is known that CAA activates complement, an inflammatory mediator, there is no information on the relationship between capillary Aß and complement activation. METHODS: We evaluated 34 autopsy brains, including 22 with CAA and 12 with other neurodegenerative diseases. We assessed the vascular density of CAA by analyzing the expression of complement (C1q, C3d, C6, C5b-9), macrophage scavenger receptor (MSR), and apolipoprotein E (ApoE). RESULTS: Capillary immunostaining for C1q, C3d, MSR, and ApoE was identified almost exclusively in CAA-type1 brains. There was intense expression of C1q, C3d, MSR, and ApoE, as well as weaker expression of C5b-9 and C6 in the arteries/ arterioles of both CAA subtypes, but not in control brains. C5b-9 and C6 were preferentially expressed in arteries/arterioles with subcortical hemorrhage or cortical superficial siderosis. Triple immunofluorescence revealed that C1q, C3d, and ApoE were colocalized with Aß in CAA brain capillaries. CONCLUSION: Complement, MSR, and ApoE were only coexpressed in the presence of Aß accumulation in capillaries, suggesting a role for complement activation in the propagation of Aß. Additionally, C5b-9 expression may be associated with hemorrhagic brain injury in CAA.
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Capilares/patologia , Angiopatia Amiloide Cerebral/patologia , Ativação do Complemento , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/biossíntese , Peptídeos beta-Amiloides/genética , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Arteríolas/metabolismo , Arteríolas/patologia , Autopsia , Encéfalo/patologia , Capilares/metabolismo , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/metabolismo , Proteínas do Sistema Complemento/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Receptores Depuradores/metabolismoRESUMO
Visual object recognition is generally known to be facilitated when targets are preceded by the same or relevant stimuli. For written words, however, the beneficial effect of priming can be reversed when primes and targets share initial syllables (e.g., "boca" and "bono"). Using fMRI, the present study explored neuroanatomical correlates of this negative syllabic priming. In each trial, participants made semantic judgment about a centrally presented target, which was preceded by a masked prime flashed either to the left or right visual field. We observed that the inhibitory priming during reading was associated with a left-lateralized effect of repetition enhancement in the inferior frontal gyrus (IFG), rather than repetition suppression in the ventral visual region previously associated with facilitatory behavioral priming. We further performed a second fMRI experiment using a classical whole-word repetition priming paradigm with the same hemifield procedure and task instruction, and obtained well-known effects of repetition suppression in the left occipito-temporal cortex. These results therefore suggest that the left IFG constitutes a fast word processing system distinct from the posterior visual word-form system and that the directions of repetition effects can change with intrinsic properties of stimuli even when participants' cognitive and attentional states are kept constant.
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Reconhecimento Visual de Modelos/fisiologia , Córtex Pré-Frontal/fisiologia , Priming de Repetição/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Leitura , Semântica , Adulto JovemRESUMO
Human cortical gray matter (GM) is structurally asymmetrical and this asymmetry has been discussed to be partly responsible for functional lateralization of human cognition and behavior. Past studies on brain asymmetry have shown mixed results so far, with some studies focusing on the global shapes of the brain's surface, such as gyrification patterns, while others focused on regional brain volumes. In this study, we investigated cortical GM asymmetries in a large sample of right-handed healthy volunteers (n = 101), using a surface-based method which allows to analyze brain cortical thickness and surface area separately. As a result, substantially different patterns of symmetry emerged between cortical thickness and surface area measures. In general, asymmetry is more prominent in the measure of surface compared to that of thickness. Such a detailed investigation of structural asymmetries in the normal brain contributes largely to our knowledge of normal brain development and also offers insights into the neurodevelopmental basis of psychiatric disorders, such as schizophrenia.
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Córtex Cerebral/anatomia & histologia , Substância Cinzenta/anatomia & histologia , Adulto , Envelhecimento/patologia , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Caracteres Sexuais , Adulto JovemRESUMO
The preservation of language function during brain surgery still poses a challenge. No intraoperative methods have been established to monitor the language network reliably. We aimed to establish intraoperative language network monitoring by means of cortico-cortical evoked potentials (CCEPs). Subjects were six patients with tumors located close to the arcuate fasciculus (AF) in the language-dominant left hemisphere. Under general anesthesia, the anterior perisylvian language area (AL) was first defined by the CCEP connectivity patterns between the ventrolateral frontal and temporoparietal area, and also by presurgical neuroimaging findings. We then monitored the integrity of the language network by stimulating AL and by recording CCEPs from the posterior perisylvian language area (PL) consecutively during both general anesthesia and awake condition. High-frequency electrical stimulation (ES) performed during awake craniotomy confirmed language function at AL in all six patients. Despite an amplitude decline (≤32%) in two patients, CCEP monitoring successfully prevented persistent language impairment. After tumor removal, single-pulse ES was applied to the white matter tract beneath the floor of the removal cavity in five patients, in order to trace its connections into the language cortices. In three patients in whom high-frequency ES of the white matter produced naming impairment, this "eloquent" subcortical site directly connected AL and PL, judging from the latencies and distributions of cortico- and subcortico-cortical evoked potentials. In conclusion, this study provided the direct evidence that AL, PL, and AF constitute the dorsal language network. Intraoperative CCEP monitoring is clinically useful for evaluating the integrity of the language network.
Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Encéfalo/cirurgia , Estimulação Elétrica/métodos , Monitorização Neurofisiológica Intraoperatória/métodos , Idioma , Adulto , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/cirurgia , Craniotomia/métodos , Imagem de Tensor de Difusão , Potenciais Evocados , Feminino , Humanos , Testes de Linguagem , Imageamento por Ressonância Magnética , Masculino , Fibras Nervosas Mielinizadas/patologia , Fibras Nervosas Mielinizadas/fisiologia , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Vias Neurais/cirurgia , Resultado do Tratamento , Substância Branca/patologia , Substância Branca/fisiopatologia , Substância Branca/cirurgia , Adulto JovemRESUMO
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that has been reported to be affected by inflammatory cells, such as microglia and macrophages, through the concept of non-cell autonomous neuronal death. Resident microglia in the human brain and monocyte-derived macrophages (MoDM) infiltrating in tissues are difficult to distinguish. Therefore, the effects of microglia and MoDMs in ALS remain poorly understood. This study aimed to investigate the role of resident microglia and MoDMs in the pathogenesis of ALS using postmortem brain and spinal cord samples. The samples used for immunohistochemical analysis included 11 cases of sporadic ALS and 11 age-matched controls. We stained the cells with TMEM119 to detect resident microglia and CCR2 to detect MoDMs. In ALS cases, TMEM119-immunopositive resident microglia were abundant in the motor cortex and subcortical white matter (SWM) of the motor area, whereas CCR2-immunopositive MoDM was similar to control cases. In addition, the mean density of CD68-immunopositive cells in the SWM significantly correlated with the mean density of pTDP-43-positive GCIs. These results suggest that resident microglial activation plays an important role in the cerebral pathogenesis of ALS and may provide novel therapeutic strategies to target excessive activation of resident microglia in ALS.
Assuntos
Esclerose Lateral Amiotrófica , Encéfalo , Proteínas de Membrana , Microglia , Humanos , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Microglia/metabolismo , Microglia/patologia , Masculino , Feminino , Idoso , Pessoa de Meia-Idade , Proteínas de Membrana/metabolismo , Encéfalo/patologia , Encéfalo/metabolismo , Macrófagos/metabolismo , Macrófagos/patologia , Receptores CCR2/metabolismo , Substância Branca/patologia , Substância Branca/metabolismo , Medula Espinal/metabolismo , Medula Espinal/patologia , Idoso de 80 Anos ou maisRESUMO
BACKGROUND: The ventral intermediate nucleus (Vim) of the thalamus is a surgical target for treating various types of tremor. Because it is difficult to visualize the Vim using standard magnetic resonance imaging, the structure is usually targeted based on the anterior and posterior commissures. This standard targeting method is practical in most patients but not in those with thalamic asymmetry. The authors examined the usefulness of quantitative susceptibility mapping (QSM) and transformed Vim atlas images to estimate the Vim localization in a patient with tremor and significant thalamic hypertrophy. OBSERVATIONS: A 51-year-old right-handed female had experienced a predominant left-hand action tremor for 6 years. Magnetic resonance imaging showed significant hypertrophy of the right thalamus and caudal shift of the thalamic ventral border. The authors referred to the QSM images to localize the decreased susceptibility area within the lateral ventral thalamic nuclei to target the Vim. In addition, the nonlinearly transformed Vim atlas images complemented the imaging-based targeting. The radiofrequency thalamotomy at the modified Vim target relieved the tremor completely. LESSONS: A combination of QSM and nonlinear transformation of the thalamic atlas can be helpful in the targeting method of the Vim for tremor patients with thalamic asymmetry.