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Parietal Lobe (parietal + lobe)
Kinds of Parietal Lobe Terms modified by Parietal Lobe Selected AbstractsTurner syndrome: Neuroimaging findings: Structural and functionalDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2009Ronan Mullaney Abstract Neuroimaging studies of Turner syndrome can advance our understanding of the X chromosome in brain development, and the modulatory influence of endocrine factors. There is increasing evidence from neuroimaging studies that TX individuals have significant differences in the anatomy, function, and metabolism of a number of brain regions; including the parietal lobe; cerebellum, amygdala, hippocampus; and basal ganglia; and perhaps differences in "connectivity" between frontal and parieto-occipital regions. Finally, there is preliminary evidence that genomic imprinting, sex hormones and growth hormone have significant modulatory effects on brain maturation in TS. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:279,283. [source] Brain dysmorphology in individuals with severe prenatal alcohol exposureDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 3 2001Sarah L Archibald MA Our previous studies revealed abnormalities on structural MRI (sMRI) in small groups of children exposed to alcohol prenatally. Microcephaly, disproportionately reduced basal ganglia volume, and abnormalities of the cerebellar vermis and corpus callosum were demonstrated. The present study used sMRI to examine in detail the regional pattern of brain hypoplasia resulting from prenatal exposure to alcohol using a higher resolution imaging protocol and larger sample sizes than reported previously. Fourteen participants (mean 11.4 years; eight females, six males) with fetal alcohol syndrome (FAS) and 12 participants (mean 14.8 years; four females, eight males) with prenatal exposure to alcohol (PEA) but without the facial features of FAS were compared to a group of 41 control participants (mean 12.8 years, 20 females, 21 males). Findings of significant microcephaly and disproportionately reduced basal ganglia volumes in the FAS group were confirmed. Novel findings were that in FAS participants, white matter volumes were more affected than gray matter volumes in the cerebrum, and parietal lobes were more affected than temporal and occipital lobes. Among subcortical structures, in contrast to the disproportionate effects on caudate nucleus, the hippocampus was relatively preserved in FAS participants. Differences between the PEA group and controls were generally non-significant; however, among a few of the structures most affected in FAS participants, there was some evidence for volume reduction in PEA participants as well, specifically in basal ganglia and the parietal lobe. There were no group differences in cerebral volume asymmetries. Severe prenatal alcohol exposure appears to produce a specific pattern of brain hypoplasia. [source] Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndromeDEVELOPMENTAL SCIENCE, Issue 3 2010Kirsten O'Hearn The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo-spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3- and 4-year-olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k -statistic) showed similar developmental profiles in typically developing 3- and 4-year-old children, but the WS profile differed from either age group. People with WS could track more objects than 3-year-olds, and the same number as 4-year-olds, but they could remember the locations of more static objects than both 3- and 4-year-olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4-year-olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development. [source] A Distinct Asymmetrical Pattern of Cortical Malformation: Large Unilateral Malformation of Cortical Development with Contralateral Periventricular Nodular Heterotopia in Three Pediatric CasesEPILEPSIA, Issue 8 2005Annapurna Poduri Summary:,Purpose: To describe a distinct asymmetrical pattern of cortical malformation with large focal malformations of cortical development (MCDs) and contralateral periventricular nodular heterotopia (PNH). Methods: We identified three patients with epilepsy and focal EEG abnormalities. Each patient underwent 1.5-Tesla magnetic resonance imaging (MRI) to obtain sagittal T1 -weighted, axial fluid-attenuated inversion recovery (FLAIR), fast spin-echo (FSE) T2 -weighted, and coronal fast spin-echo inversion recovery (FSEIR) T2 -weighted images; coronal spoiled gradient recalled (SPGR) T1 -weighted images were obtained in two cases. Results: Patient 1, an 18-year-old right-handed man, had a 4-year history of intractable seizures. MRI revealed a right frontal subcortical heterotopia (SH) and a single left anterior PNH. Patient 2, a 10-year-old left-handed boy, had a 4-year history of epilepsy. MRI revealed a large region of SH in the left temporal, parietal, and occipital lobes and three right-sided PNH. Patient 3, a 16-month-old girl, had medically refractory infantile spasms. MRI revealed a large MCD in the left parietal lobe with contiguous underlying periventricular heterotopia as well as a small contralateral PNH. Conclusions: These cases together illustrate a distinct asymmetrical pattern of a large focal MCD with small contralateral PNH. The asymmetrical involvement of the two hemispheres suggests that the stage of maximal disruption of cortical development may differ between the two hemispheres. Further study into the mechanisms underlying such asymmetrical patterns of cortical malformation should enhance our understanding of cortical development as well as hemispheric lateralization. [source] Seizure Semiology in the Elderly: A Video AnalysisEPILEPSIA, Issue 3 2004Christoph Kellinghaus Summary: Purpose: To describe the seizure semiology of patients older than 60 years and to compare it with that of a control group of younger adults matched according to the epilepsy diagnosis. Methods: Available videotapes of all patients aged 60 years and older who underwent long-term video-EEG evaluation at the Cleveland Clinic Foundation (CCF) between January 1994 and March 2002 were analyzed by two observers blinded to the clinical data. A younger adult control group was matched according to the epilepsy diagnosis, and their seizures also were analyzed. Results: Fifty-four (3.3%) of the 1,633 patients were 60 years or older at the time of admission. For 21 of them, at least one epileptic seizure was recorded. Nineteen patients had focal epilepsy (nine temporal lobe, two frontal lobe, two parietal lobe, eight nonlocalized), and two patients had generalized epilepsy. Seventy-three seizures of the elderly patients and 85 seizures of the 21 control patients were analyzed. In nine elderly patients and 14 control patients, at least one of their seizures started with an aura. Eleven elderly patients and 19 control patients lost responsiveness during their seizures. Approximately two thirds of the patients in both groups had automatisms during the seizures. Both focal and generalized motor seizures (e.g., clonic or tonic seizures) were seen less frequently in the elderly. Conclusions: Only a small percentage of the patients admitted to a tertiary epilepsy referral center for long-term video-EEG monitoring are older than 60 years. All seizure types observed in the elderly also were seen in the younger control group, and vice versa. Simple motor seizures were seen less frequently in the elderly. [source] Clinical features of non-hypertensive lobar intracerebral hemorrhage related to cerebral amyloid angiopathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2010M. Hirohata Background and purpose: The present study aims to clarify the clinical features of non-hypertensive cerebral amyloid angiopathy-related lobar intracerebral hemorrhage (CAA-L-ICH). Methods: We investigated clinical, laboratory, and neuroimaging findings in 41 patients (30, women; 11, men) with pathologically supported CAA-L-ICH from 303 non-hypertensive Japanese patients aged ,55, identified via a nationwide survey as symptomatic CAA-L-ICH. Results: The mean age of patients at onset of CAA-L-ICH was 73.2 ± 7.4 years; the number of patients increased with age. The corrected female-to-male ratio for the population was 2.2, with significant female predominance. At onset, 7.3% of patients received anti-platelet therapy. In brain imaging studies, the actual frequency of CAA-L-ICHs was higher in the frontal and parietal lobes; however, after correcting for the estimated cortical volume, the parietal lobe was found to be the most frequently affected. CAA-L-ICH recurred in 31.7% of patients during the average 35.3-month follow-up period. The mean interval between intracerebral hemorrhages (ICHs) was 11.3 months. The case fatality rate was 12.2% at 1 month and 19.5% at 12 months after initial ICH. In 97.1% of patients, neurosurgical procedures were performed without uncontrollable intraoperative or post-operative hemorrhage. Conclusions: Our study revealed the clinical features of non-hypertensive CAA-L-ICH, including its parietal predilection, which will require further study with a larger number of patients with different ethnic backgrounds. [source] Cortical mechanisms of smooth pursuit eye movements with target blanking.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2004An fMRI study Abstract Smooth pursuit eye movements are evoked by retinal image motion of visible moving objects and can also be driven by the internal representation of a target due to extraretinal mechanisms (e.g. efference copy). To delineate the corresponding neuronal correlates, functional magnetic resonance imaging at 1.5 T was applied during smooth pursuit at 10 °/s with continuous target presentation and target blanking for 1 s to 16 right-handed healthy males. Eye movements were assessed during scanning sessions by infra-red reflection oculography. Smooth pursuit performance was optimal when the target was visible but decreased to a residual velocity of about 30% of the velocity observed during continuous target presentation. Random effects analysis of the imaging data yielded an activation pattern for smooth pursuit in the absence of a visual target (in contrast to continuous target presentation) which included a number of cortical areas in which extraretinal information is available such as the frontal eye field, the superior parietal lobe, the anterior and the posterior intraparietal sulcus and the premotor cortex, and also the supplementary and the presupplementary eye field, the supramarginal gyrus, the dorsolateral prefrontal cortex, cerebellar areas and the basal ganglia. We suggest that cortical mechanisms such as prediction, visuo-spatial attention and transformation, multimodal visuomotor control and working memory are of special importance for maintaining smooth pursuit eye movements in the absence of a visible target. [source] Source-based morphometry: The use of independent component analysis to identify gray matter differences with application to schizophreniaHUMAN BRAIN MAPPING, Issue 3 2009Lai Xu Abstract We present a multivariate alternative to the voxel-based morphometry (VBM) approach called source-based morphometry (SBM), to study gray matter differences between patients and healthy controls. The SBM approach begins with the same preprocessing procedures as VBM. Next, independent component analysis is used to identify naturally grouping, maximally independent sources. Finally, statistical analyses are used to determine the significant sources and their relationship to other variables. The identified "source networks," groups of spatially distinct regions with common covariation among subjects, provide information about localization of gray matter changes and their variation among individuals. In this study, we first compared VBM and SBM via a simulation and then applied both methods to real data obtained from 120 chronic schizophrenia patients and 120 healthy controls. SBM identified five gray matter sources as significantly associated with schizophrenia. These included sources in the bilateral temporal lobes, thalamus, basal ganglia, parietal lobe, and frontotemporal regions. None of these showed an effect of sex. Two sources in the bilateral temporal and parietal lobes showed age-related reductions. The most significant source of schizophrenia-related gray matter changes identified by SBM occurred in the bilateral temporal lobe, while the most significant change found by VBM occurred in the thalamus. The SBM approach found changes not identified by VBM in basal ganglia, parietal, and occipital lobe. These findings show that SBM is a multivariate alternative to VBM, with wide applicability to studying changes in brain structure. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Discrete dynamic Bayesian network analysis of fMRI dataHUMAN BRAIN MAPPING, Issue 1 2009John Burge Abstract We examine the efficacy of using discrete Dynamic Bayesian Networks (dDBNs), a data-driven modeling technique employed in machine learning, to identify functional correlations among neuroanatomical regions of interest. Unlike many neuroimaging analysis techniques, this method is not limited by linear and/or Gaussian noise assumptions. It achieves this by modeling the time series of neuroanatomical regions as discrete, as opposed to continuous, random variables with multinomial distributions. We demonstrated this method using an fMRI dataset collected from healthy and demented elderly subjects (Buckner, et al., 2000: J Cogn Neurosci 12:24-34) and identify correlates based on a diagnosis of dementia. The results are validated in three ways. First, the elicited correlates are shown to be robust over leave-one-out cross-validation and, via a Fourier bootstrapping method, that they were not likely due to random chance. Second, the dDBNs identified correlates that would be expected given the experimental paradigm. Third, the dDBN's ability to predict dementia is competitive with two commonly employed machine-learning classifiers: the support vector machine and the Gaussian naïve Bayesian network. We also verify that the dDBN selects correlates based on non-linear criteria. Finally, we provide a brief analysis of the correlates elicited from Buckner et al.'s data that suggests that demented elderly subjects have reduced involvement of entorhinal and occipital cortex and greater involvement of the parietal lobe and amygdala in brain activity compared with healthy elderly (as measured via functional correlations among BOLD measurements). Limitations and extensions to the dDBN method are discussed. Hum Brain Mapp, 2009. © 2007 Wiley-Liss, Inc. [source] Cortical sources of the early components of the visual evoked potentialHUMAN BRAIN MAPPING, Issue 2 2002Francesco Di Russo Abstract This study aimed to characterize the neural generators of the early components of the visual evoked potential (VEP) to isoluminant checkerboard stimuli. Multichannel scalp recordings, retinotopic mapping and dipole modeling techniques were used to estimate the locations of the cortical sources giving rise to the early C1, P1, and N1 components. Dipole locations were matched to anatomical brain regions visualized in structural magnetic resonance imaging (MRI) and to functional MRI (fMRI) activations elicited by the same stimuli. These converging methods confirmed previous reports that the C1 component (onset latency 55 msec; peak latency 90,92 msec) was generated in the primary visual area (striate cortex; area 17). The early phase of the P1 component (onset latency 72,80 msec; peak latency 98,110 msec) was localized to sources in dorsal extrastriate cortex of the middle occipital gyrus, while the late phase of the P1 component (onset latency 110,120 msec; peak latency 136,146 msec) was localized to ventral extrastriate cortex of the fusiform gyrus. Among the N1 subcomponents, the posterior N150 could be accounted for by the same dipolar source as the early P1, while the anterior N155 was localized to a deep source in the parietal lobe. These findings clarify the anatomical origin of these VEP components, which have been studied extensively in relation to visual-perceptual processes. Hum. Brain Mapping 15:95,111, 2001. © 2001 Wiley-Liss, Inc. [source] Regional cerebral blood flow responses to hyperventilation during sevoflurane anaesthesia studied with PETACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2010L. SCHLÜNZEN Background: Arterial carbon dioxide tension (PaCO2) is an important factor controlling cerebral blood flow (CBF) in neurosurgical patients. It is still unclear whether the hypocapnia-induced decrease in CBF is a general effect on the brain or rather linked to specific brain regions. We evaluated the effects of hyperventilation on regional cerebral blood flow (rCBF) in healthy volunteers during sevoflurane anaesthesia measured with positron emission tomography (PET). Methods: Eight human volunteers were anaesthetized with sevoflurane 1 MAC, while exposed to hyperventilation. During 1 MAC sevoflurane at normocapnia and 1 MAC sevoflurane at hypocapnia, one H215O scan was performed. Statistical parametric maps and conventional regions of interest analysis were used for estimating rCBF differences. Results: Cardiovascular parameters were maintained constant over time. During hyperventilation, the mean PaCO2 was decreased from 5.5 ± 0.7 to 3.8 ± 0.9 kPa. Total CBF decreased during the hypocapnic state by 44%. PET revealed wide variations in CBF between regions. The greatest values of vascular responses during hypocapnia were observed in the thalamus, medial occipitotemporal gyrus, cerebellum, precuneus, putamen and insula regions. The lowest values were observed in the superior parietal lobe, middle and inferior frontal gyrus, middle and inferior temporal gyrus and precentral gyrus. No increases in rCBF were observed. Conclusions: This study reports highly localized and specific changes in rCBF during hyperventilation in sevoflurane anaesthesia, with the most pronounced decreases in the sub cortical grey matter. Such regional heterogeneity of the cerebral vascular response should be considered in the assessment of cerebral perfusion reserve during hypocapnia. [source] Functional magnetic resonance imaging of human cognitive processesJAPANESE PSYCHOLOGICAL RESEARCH, Issue 1 2000Tomohisa Okada Functional magnetic resonance imaging (fMRI) is now widely accepted as a tool for analyzing human brain function. Since the realization of fMRI in the early 1990s, numerous reports have been published. In this paper, we present three studies. The first examined syntactic processing of Japanese sentences and the results prove that Broca's area is involved in the use of grammar. The second study compared binocular with monocular stereopsis. There were significant activations in the right inferior parietal lobe. The third study concerned the encoding and retrieval processes underlying face recognition. It revealed activations mainly in the right prefrontal areas, which is contrary to the hemispheric encoding and retrieval asymmetry (HERA) theory. fMRI will continue to play an important role in the analysis of human brain function. [source] Magnetic resonance imaging and proton MR spectroscopy of the brain in a patient with carbohydrate-deficient glycoprotein syndrome type IJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2003Mayumi Takeuchi MD Abstract This is a report on a case of carbohydrate-deficient glycoprotein syndrome (CDGS) with neurological deficits. Magnetic resonance (MR) images showed remarkable atrophy of the cerebellum and brainstem, and hypointensity was seen in the pallidum on diffusion-weighted images (DWI), suggesting deposits of metal substances. In the cerebellum, proton MR spectroscopy (MRS) showed decreased concentrations of N-acetylaspartate and a complex of glutamine and glutamate (Glx) while the concentration of myo-inositol was increased, indicating neuronal impairment and gliosis. In the parietal lobe, there was an increased concentration of Glx, possibly reflecting dysfunction caused by liver injury. J. Magn. Reson. Imaging 2003;17:722,725. © 2003 Wiley-Liss, Inc. [source] Event-Related fMRI of Inhibitory Control in the Predominantly Inattentive and Combined Subtypes of ADHDJOURNAL OF NEUROIMAGING, Issue 3 2009Mary V. Solanto PhD ABSTRACT BACKGROUND AND PURPOSE To examine the neurophysiological basis for the pronounced differences in hyperactivity and impulsiveness that distinguish the predominantly inattentive type of attention-deficit/hyperactivity disorder (ADHD-PI) from the combined type of the disorder (ADHD-C). METHODS Event-related brain responses to a go/no-go test of inhibitory control were measured with functional magnetic resonance imaging (fMRI) in 11 children with ADHD-C and 9 children with ADHD-PI, aged 7 to 13 years, who were matched for age, sex, and intelligence. RESULTS There were no significant group differences in task performance. Children with ADHD-C and ADHD-PI activated overlapping regions of right inferior frontal gyrus, right superior temporal lobe, and left inferior parietal lobe during inhibitory control. However, the magnitude of the activation in the temporal and parietal regions, as well as in the bilateral middle frontal gyrus, was greater in children with ADHD-PI than those with ADHD-C. Conversely, children with ADHD-C activated bilateral medial occipital lobe to a greater extent than children with ADHD-PI. CONCLUSIONS The results provide preliminary evidence that phenotypic differences between the ADHD-C and ADHD-PI subtypes are associated with differential activation of regions that have previously been implicated in the pathophysiology of ADHD and are thought to mediate executive and attentional processes. [source] An fMRI Study of Number Processing in Children With Fetal Alcohol SyndromeALCOHOLISM, Issue 8 2010Ernesta M. Meintjes Background:, Number processing deficits are frequently seen in children exposed to alcohol in utero. Methods:, Functional magnetic resonance imaging was used to examine the neural correlates of number processing in 15 right-handed, 8- to 12-year-old children diagnosed with fetal alcohol syndrome (FAS) or partial FAS (PFAS) and 18 right-handed, age- and gender-matched controls from the Cape Coloured (mixed ancestry) community in Cape Town, South Africa, using Proximity Judgment and Exact Addition tasks. Results:, Control children activated the expected fronto-parietal network during both tasks, including the anterior horizontal intraparietal sulcus (HIPS), left posterior HIPS, left precentral sulcus, and posterior medial frontal cortex. By contrast, on the Proximity Judgment task, the exposed children recruited additional parietal pathways involving the right and left angular gyrus and posterior cingulate/precuneus, which may entail verbally mediated recitation of numbers and/or subtraction to assess relative numerical distances. During Exact Addition, the exposed children exhibited more diffuse and widespread activations, including the cerebellar vermis and cortex, which have been found to be activated in adults engaged in particularly challenging number processing problems. Conclusions:, The data suggest that, whereas control children rely primarily on the fronto-parietal network identified in previous studies to mediate number processing, children with FAS/PFAS recruit a broader range of brain regions to perform these relatively simple number processing tasks. Our results are consistent with structural neuroimaging findings indicating that the parietal lobe is relatively more affected by prenatal alcohol exposure and provide the first evidence for brain activation abnormalities during number processing in children with FAS/PFAS, effects that persist even after controlling statistically for group differences in total intracranial volume and IQ. [source] Parietal Gray Matter Volume Loss Is Related to Spatial Processing Deficits in Long-Term Abstinent Alcoholic MenALCOHOLISM, Issue 10 2009George Fein Background:, We previously demonstrated relatively intact cognitive function (with the exception of suggestive evidence for persistent deficits in spatial information processing) in middle-aged long-term abstinent alcoholics (LTAA, abstinent for 6 months or more) compared to age and gender comparable nonalcoholic controls (NAC) (Fein et al., 2006). Methods:, In the current study, we examine cortical gray matter volumes in the same samples to determine whether gray matter volumes in LTAA are consistent with the cognitive results , i.e., exhibiting gray matter volumes comparable to NAC in most brain regions, except for possible indications of persistent shrinkage in the parietal lobe subserving spatial information processing. Results:, We found gray matter shrinkage in LTAA in the parietal lobe consistent with the spatial processing deficits in this same sample. More compelling, in LTAA, the magnitude of parietal gray matter shrinkage was negatively associated with spatial processing domain performance and positively associated with alcohol dose. Gray matter volume deficits were present in the occipital and other cortical tissue, but poorer visuospatial test performance correlated significantly with smaller volumes in the parietal cortex only. Conclusions:, Taken together, the cognitive and structural imaging data provide compelling evidence that chronic alcohol abuse results in shrinkage of the parietal cortex with associated deficits in spatial information processing. [source] Amnestic mild cognitive impairment in Parkinson's disease: A brain perfusion SPECT study,,MOVEMENT DISORDERS, Issue 3 2009Flavio Nobili MD Abstract The purpose of this study was to investigate cortical dysfunction in Parkinson's disease (PD) patients with amnestic deficit (PD-MCI). Perfusion single photon emission computed tomography was performed in 15 PD-MCI patients and compared (statistical parametric mapping [SPM2]) with three groups, i.e., healthy subjects (CTR), cognitively intact PD patients (PD), and common amnestic MCI patients (aMCI). Age, depression, and UPDRS-III scores were considered as confounding variables. PD-MCI group (P < 0.05, false discovery rate,corrected for multiple comparisons) showed relative hypoperfusion in bilateral posterior parietal lobe and in right occipital lobe in comparison to CTR. As compared to aMCI, MCI-PD demonstrated hypoperfusion in bilateral posterior parietal and occipital areas, mainly right cuneus and angular gyrus, and left precuneus and middle occipital gyrus. With a less conservative threshold (uncorrected P < 0.01), MCI-PD showed hypoperfusion in a left parietal region, mainly including precuneus and inferior parietal lobule, and in a right temporal-parietal-occipital region, including middle occipital and superior temporal gyri, and cuneus-precuneus, as compared to PD. aMCI versus PD-MCI showed hypoperfusion in bilateral medial temporal lobe, anterior cingulate, and left orbitofrontal cortex. PD-MCI patients with amnestic deficit showed cortical dysfunction in bilateral posterior parietal and occipital lobes, a pattern that can be especially recognized versus both controls and common aMCI patients, and to a lesser extent versus cognitively intact PD. The relevance of this pattern in predicting dementia should be evaluated in longitudinal studies. © 2008 Movement Disorder Society [source] Multifocal dysembryoplastic neuroepithelial tumor with signs of atypia after regrowthNEUROPATHOLOGY, Issue 4 2007Jens Schittenhelm We report the case of a multifocal dysembryoplastic neuroepithelial tumor (DNT) in a 7-year-old girl with local tumor regrowth 6 years later. The tumor was localized in the right parietal lobe extending from the cortex into the periventricular white matter. After subtotal resection of a histopathologically confirmed DNT we observed unexpected tumor progression in long-term follow-up. Therefore, a second surgery was performed when the patient was 14 years of age. In neuropathological examination of the second specimen the tumor showed an increased cellularity and pleomorphism, microvascular proliferations, an elevated proliferative activity (MIB1-index focally up to 10%) and cellular atypia not typical for WHO grade I DNT. Furthermore, MRI studies showed additional supratentorial and infratentorial lesions which remained stable over years and are also well consistent with DNTs. Thus, an unusual form of a DNT with multifocal lesions, local regrowth and morphological transformation is supposed. [source] Pick's disease with Pick bodies: An unusual autopsy case showing degeneration of the pontine nucleus, dentate nucleus, Clarke's column, and lower motor neuronNEUROPATHOLOGY, Issue 1 2007Tatsuro Oda We report a 51-year-old female with Pick's disease with Pick bodies (PDPB) showing a brainweight of 530 g. This case was considered to be a very rare case of PDPB, in which the lesion developed in the temporal and frontal lobes and later spread to the parietal lobe, occipital lobe, brainstem, cerebellum and spinal cord. This case showed very atypical clinicopathological findings. Clinically, bulging eyes and myoclonus were observed. Neuropathologically, Pick bodies were widely distributed beyond the usual distribution areas to the parietal cortices, occipital cortices, dentate nuclei, motor neuron nuclei in the brain stem, and spinal cord. The atypical clinical symptoms and the widespread neuropathological abnormalities observed in this case seem to represent an extremely extended form of PDPB. [source] Leptomeningeal carcinomatosis from urinary bladder adenocarcinoma: A clinicopathological case studyNEUROPATHOLOGY, Issue 1 2005Kaoru Sugimori We report a 73-year-old male patient with leptomeningeal metastasis from urinary bladder adenocarcinoma. He was presented, with, prominent, hyperactive, delirium, during the course of the disease. Meningeal carcinomatosis was detected 5 days before his death, but the primary site of the malignant tumor could not be determined. Necropsy revealed leptomeningeal infiltration of many adenocarcinoma cells that covered the cerebrum. The leptomeninges of the right middle frontal gyrus, superior temporal gyrus, precentral gyrus and inferior parietal lobe were most severely affected by tumor cell infiltration. Cerebral edema was found to extensively cover the basal part of the temporal lobe. In the cerebrum, tumor cells were clustered in the perivascular spaces and had invaded localized areas of the frontal lobe. Vascular cell adhesion molecule (VCAM)-1 expression was detected in the small vessels of the cerebral upper cortical layers and of temporal subcortical u-fibers. Numerous astrocytes positive for cytokeratin AE1/AE3 were found in the frontal and temporal lobes. Meningeal carcinomatosis from urinary bladder adenocarcinoma is extremely rare and up-regulation of the adhesion molecules in the meningeal adenocarcinoma was confirmed. [source] The electrophysiological correlates sustaining the retrieval of face,name associations: An ERP studyPSYCHOPHYSIOLOGY, Issue 4 2004F. Joassin Abstract An ERP study on 9 healthy participants was carried out to temporally constrain the neural network proposed by Campanella et al. (2001) in a PET study investigating the cerebral areas involved in the retrieval of face,name associations. Three learning sessions served to familiarize the participants with 24 face,name associations grouped in 12 male/female couples. During EEG recording, participants were confronted with four experimental conditions, requiring the retrieval of previously learned couples on the basis of the presentation of name,name (NN), face,face (FF), name,face (NF), or face,name (FN) pairs of stimuli. The main analysis of this experiment consisted in the subtraction of the nonmixed conditions (NN and FF) from the mixed conditions (NF and FN). It revealed two main ERP components: a negative wave peaking at left parieto-occipital sites around 285 ms and its positive counterpart recorded at left centro-frontal electrodes around 300 ms. Moreover, a dipole modeling using three dipoles whose localization corresponded to the three cerebral areas observed in the PET study (left inferior frontal gyrus, left medial frontal gyrus, left inferior parietal lobe) explained more than 90% of the variance of the results. The complementarity between anatomical and neurophysiological techniques allowed us to discuss the temporal course of these cerebral activities and to propose an interactive and original anatomo-temporal model of the retrieval of face,name associations. [source] Structural brain abnormalities in adolescents with autism spectrum disorder and patients with attention deficit/hyperactivity disorderTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 12 2007Sarah Brieber Background:, Although autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) are two distinct neurodevelopmental diseases, they share behavioural, neuropsychological and neurobiological characteristics. For the identification of endophenotypes across diagnostic categories, further investigations of phenotypic overlap between ADHD and autism at the behavioural, neurocognitive, and brain levels are needed. Methods:, We examined regional grey matter differences and similarities in children and adolescents with ASD and ADHD in comparison to healthy controls using structural magnetic resonance imaging (MRI) and voxel-based morphometry. Results:, With regard to clinical criteria, the clinical groups did not differ with respect to ADHD symptoms; however, only patients with ASD showed deficits in social communication and interaction, according to parental rating. Structural abnormalities across both clinical groups compared to controls became evident as grey matter reductions in the left medial temporal lobe and as higher grey matter volumes in the left inferior parietal cortex. In addition, autism-specific brain abnormalities were found as increased grey matter volume in the right supramarginal gyrus. Conclusions:, While the shared structural deviations in the medial temporal lobe might be attributed to an unspecific delay in brain development and might be associated with memory deficits, the structural abnormalities in the inferior parietal lobe may correspond to attentional deficits observed in both ASD and ADHD. By contrast, the autism-specific grey matter abnormalities near the right temporo-parietal junction may be associated with impaired ,theory of mind' abilities. These findings shed some light on both similarities and differences in the neurocognitive profiles of ADHD and ASD patients. [source] Abnormal cerebellum density in victims of rape with post-traumatic stress disorder: Voxel-based analysis of magnetic resonance imaging investigationASIA-PACIFIC PSYCHIATRY, Issue 3 2010Shuang-Ge Sui MD MBA Abstract Introduction: Based on early studies of non-motor function in the cerebellum and dysfunction in the cerebellum of post-traumatic stress disorder (PTSD) patients, we presumed that the cerebellum was involved in the neuropathology of cognitive and emotional processing of PTSD patients, while the density of some sub-areas of the cerebellum of PTSD patients was most likely abnormal. Methods: Eleven female victims of rape with PTSD and 12 age-matched female normal controls received 1.5 T 3D magnetic resonance imaging (MRI) scan. The scans were then analyzed using the voxel-based morphometry 2 (VBM2) toolbox. Results: Victims of rape with PTSD showed increased cerebellum density on the left side compared with normal controls (P<0.001), especially in the pyramis (x=,9, y=,72, z=,36; k=519; t=4.70), uvula (x=,4, y=,66, z=,35; k=256; t=4.02), declive (x=,6, y=,69, z=,30; k=213; t=3.84) and nodule (x=,4, y=,63, z=,31; k=147; t=3.93). In addition, compared with normal controls, the PTSD group showed significant differences in gray matter density of other brain areas, including the frontal lobe, parietal lobe, occipital lobe (P<0.001), insula, posterior cingulate, amygdala and hippocampus (P<0.005). Discussion: These finding suggest that the cerebellum may be involved in the neuropathology and functional compensation in the neurocircuitry of PTSD. [source] A case of Kleine,Levin syndrome examined with SPECT and neuropsychological testingACTA NEUROLOGICA SCANDINAVICA, Issue 4 2002A.-M. Landtblom A case of Kleine,Levin syndrome with typical periodic hypersomnia and bulemia was diagnosed. On examination with single photo emission tomography (SPECT) (CERETEC®) during a relapse period and 2 weeks later there was marked cortical hypoperfusion of the frontal and temporal lobes, especially on the left side as well as in the right parietal lobe. Neuropsychological testing performed 1 week after a relapse showed a reduction in encoding to memory function of verbal learning indicating neocortical damage of the left fronto-temporal region. A follow-up 2 months later after the patient had spontaneously recovered showed only a slight left fronto-temporal disturbance. CT and MRI of the brain were normal although the MRI showed a large and asymmetric mamillary body. Neuropsychological testing 6 years after recovery showed pronounced reduction in short-time verbal and visual memory. Seven years after recovery SPECT demonstrated a normalized frontal perfusion but still a slight hypoperfusion in the left temporal lobe. Our results correlate to autopsy findings in two cases described previously. [source] Brain dysmorphology in individuals with severe prenatal alcohol exposureDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 3 2001Sarah L Archibald MA Our previous studies revealed abnormalities on structural MRI (sMRI) in small groups of children exposed to alcohol prenatally. Microcephaly, disproportionately reduced basal ganglia volume, and abnormalities of the cerebellar vermis and corpus callosum were demonstrated. The present study used sMRI to examine in detail the regional pattern of brain hypoplasia resulting from prenatal exposure to alcohol using a higher resolution imaging protocol and larger sample sizes than reported previously. Fourteen participants (mean 11.4 years; eight females, six males) with fetal alcohol syndrome (FAS) and 12 participants (mean 14.8 years; four females, eight males) with prenatal exposure to alcohol (PEA) but without the facial features of FAS were compared to a group of 41 control participants (mean 12.8 years, 20 females, 21 males). Findings of significant microcephaly and disproportionately reduced basal ganglia volumes in the FAS group were confirmed. Novel findings were that in FAS participants, white matter volumes were more affected than gray matter volumes in the cerebrum, and parietal lobes were more affected than temporal and occipital lobes. Among subcortical structures, in contrast to the disproportionate effects on caudate nucleus, the hippocampus was relatively preserved in FAS participants. Differences between the PEA group and controls were generally non-significant; however, among a few of the structures most affected in FAS participants, there was some evidence for volume reduction in PEA participants as well, specifically in basal ganglia and the parietal lobe. There were no group differences in cerebral volume asymmetries. Severe prenatal alcohol exposure appears to produce a specific pattern of brain hypoplasia. [source] Clinical features of non-hypertensive lobar intracerebral hemorrhage related to cerebral amyloid angiopathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2010M. Hirohata Background and purpose: The present study aims to clarify the clinical features of non-hypertensive cerebral amyloid angiopathy-related lobar intracerebral hemorrhage (CAA-L-ICH). Methods: We investigated clinical, laboratory, and neuroimaging findings in 41 patients (30, women; 11, men) with pathologically supported CAA-L-ICH from 303 non-hypertensive Japanese patients aged ,55, identified via a nationwide survey as symptomatic CAA-L-ICH. Results: The mean age of patients at onset of CAA-L-ICH was 73.2 ± 7.4 years; the number of patients increased with age. The corrected female-to-male ratio for the population was 2.2, with significant female predominance. At onset, 7.3% of patients received anti-platelet therapy. In brain imaging studies, the actual frequency of CAA-L-ICHs was higher in the frontal and parietal lobes; however, after correcting for the estimated cortical volume, the parietal lobe was found to be the most frequently affected. CAA-L-ICH recurred in 31.7% of patients during the average 35.3-month follow-up period. The mean interval between intracerebral hemorrhages (ICHs) was 11.3 months. The case fatality rate was 12.2% at 1 month and 19.5% at 12 months after initial ICH. In 97.1% of patients, neurosurgical procedures were performed without uncontrollable intraoperative or post-operative hemorrhage. Conclusions: Our study revealed the clinical features of non-hypertensive CAA-L-ICH, including its parietal predilection, which will require further study with a larger number of patients with different ethnic backgrounds. [source] Enhanced effectiveness in visuo-haptic object-selective brain regions with increasing stimulus salienceHUMAN BRAIN MAPPING, Issue 5 2010Sunah Kim Abstract The occipital and parietal lobes contain regions that are recruited for both visual and haptic object processing. The purpose of the present study was to characterize the underlying neural mechanisms for bimodal integration of vision and haptics in these visuo-haptic object-selective brain regions to find out whether these brain regions are sites of neuronal or areal convergence. Our sensory conditions consisted of visual-only (V), haptic-only (H), and visuo-haptic (VH), which allowed us to evaluate integration using the superadditivity metric. We also presented each stimulus condition at two different levels of signal-to-noise ratio or salience. The salience manipulation allowed us to assess integration using the rule of inverse effectiveness. We were able to localize previously described visuo-haptic object-selective regions in the lateral occipital cortex (lateral occipital tactile-visual area) and the intraparietal sulcus, and also localized a new region in the left anterior fusiform gyrus. There was no evidence of superadditivity with the VH stimulus at either level of salience in any of the regions. There was, however, a strong effect of salience on multisensory enhancement: the response to the VH stimulus was more enhanced at higher salience across all regions. In other words, the regions showed enhanced integration of the VH stimulus with increasing effectiveness of the unisensory stimuli. We called the effect "enhanced effectiveness." The presence of enhanced effectiveness in visuo-haptic object-selective brain regions demonstrates neuronal convergence of visual and haptic sensory inputs for the purpose of processing object shape. Hum Brain Mapp, 2010. © 2009 Wiley-Liss, Inc. [source] Source-based morphometry: The use of independent component analysis to identify gray matter differences with application to schizophreniaHUMAN BRAIN MAPPING, Issue 3 2009Lai Xu Abstract We present a multivariate alternative to the voxel-based morphometry (VBM) approach called source-based morphometry (SBM), to study gray matter differences between patients and healthy controls. The SBM approach begins with the same preprocessing procedures as VBM. Next, independent component analysis is used to identify naturally grouping, maximally independent sources. Finally, statistical analyses are used to determine the significant sources and their relationship to other variables. The identified "source networks," groups of spatially distinct regions with common covariation among subjects, provide information about localization of gray matter changes and their variation among individuals. In this study, we first compared VBM and SBM via a simulation and then applied both methods to real data obtained from 120 chronic schizophrenia patients and 120 healthy controls. SBM identified five gray matter sources as significantly associated with schizophrenia. These included sources in the bilateral temporal lobes, thalamus, basal ganglia, parietal lobe, and frontotemporal regions. None of these showed an effect of sex. Two sources in the bilateral temporal and parietal lobes showed age-related reductions. The most significant source of schizophrenia-related gray matter changes identified by SBM occurred in the bilateral temporal lobe, while the most significant change found by VBM occurred in the thalamus. The SBM approach found changes not identified by VBM in basal ganglia, parietal, and occipital lobe. These findings show that SBM is a multivariate alternative to VBM, with wide applicability to studying changes in brain structure. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Neural basis of first and second language processing of sentence-level linguistic prosodyHUMAN BRAIN MAPPING, Issue 2 2007Jackson Gandour Abstract A fundamental question in multilingualism is whether the neural substrates are shared or segregated for the two or more languages spoken by polyglots. This study employs functional MRI to investigate the neural substrates underlying the perception of two sentence-level prosodic phenomena that occur in both Mandarin Chinese (L1) and English (L2): sentence focus (sentence-initial vs. -final position of contrastive stress) and sentence type (declarative vs. interrogative modality). Late-onset, medium proficiency Chinese-English bilinguals were asked to selectively attend to either sentence focus or sentence type in paired three-word sentences in both L1 and L2 and make speeded-response discrimination judgments. L1 and L2 elicited highly overlapping activations in frontal, temporal, and parietal lobes. Furthermore, region of interest analyses revealed that for both languages the sentence focus task elicited a leftward asymmetry in the supramarginal gyrus; both tasks elicited a rightward asymmetry in the mid-portion of the middle frontal gyrus. A direct comparison between L1 and L2 did not show any difference in brain activation in the sentence type task. In the sentence focus task, however, greater activation for L2 than L1 occurred in the bilateral anterior insula and superior frontal sulcus. The sentence focus task also elicited a leftward asymmetry in the posterior middle temporal gyrus for L1 only. Differential activation patterns are attributed primarily to disparities between L1 and L2 in the phonetic manifestation of sentence focus. Such phonetic divergences lead to increased computational demands for processing L2. These findings support the view that L1 and L2 are mediated by a unitary neural system despite late age of acquisition, although additional neural resources may be required in task-specific circumstances for unequal bilinguals. Hum. Brain Mapp, 2007. © 2006 Wiley-Liss, Inc. [source] Increased oxidative damage in nuclear and mitochondrial DNA in mild cognitive impairmentJOURNAL OF NEUROCHEMISTRY, Issue 3 2006Jianquan Wang Abstract Increasing evidence suggests that oxidative damage is associated with normal aging and several neurodegenerative diseases. Mild cognitive impairment (MCI), the phase between normal aging and early dementia, is a common problem in the elderly with many subjects going on to develop Alzheimer's disease (AD). Although increased DNA oxidation is observed in the AD brain, it is unclear when the oxidative damage begins. To determine if DNA oxidation occurs in the brain of subjects with MCI, we quantified multiple oxidized bases in nuclear and mitochondrial DNA isolated from frontal, parietal and temporal lobes and cerebellum of short post-mortem interval autopsies of eight amnestic patients with MCI and six age-matched control subjects using gas chromatography/mass spectrometry with selective ion monitoring. We found statistically significant elevations (p < 0.05) of 8-hydroxyguanine, a widely studied biomarker of DNA damage, in MCI nuclear DNA from frontal and temporal lobe and in mitochondrial DNA from the temporal lobe compared with age-matched control subjects. Levels of 8-hydroxyadenine and 4,6-diamino-5-formamidopyrimidine were significantly elevated in nuclear DNA from all three neocortical regions in MCI. Statistically significant elevations of 4,6-diamino-5-formamidopyrimidine were also observed in mitochondrial DNA of MCI temporal, frontal and parietal lobes. These results suggest that oxidative damage to nuclear and mitochondrial DNA occurs in the earliest detectable phase of AD and may play a meaningful role in the pathogenesis of this disease. [source] | |||||||||||||||||||||||||||||||