Showing papers by "David C. Reutens published in 2013"
TL;DR: A minimum deformation atlas was created, which was hierarchically segmented into 74 neocortical and cortical-related regions, making it the most detailed atlas of the mouse neocortex currently available.
186 citations
TL;DR: The data indicate that embryonic HDAC inhibition alone can cause abnormal social behaviors in mice, which serves as a molecular understanding of infant outcomes following mild VPA exposure in utero.
74 citations
TL;DR: A fully automated pipeline that optimizes histological 3D reconstructions is provided, providing a potentially powerful solution not only for primary human post mortem research institutions in neuropsychiatric research, but also to help alleviate the massive workloads in neuroanatomical atlas initiatives.
Abstract: Ultra-high field magnetic resonance imaging (MRI) became increasingly relevant for in vivo neuroscientific research because of improved spatial resolutions. However, this is still the unchallenged domain of histological studies, which long played an important role in the investigation of neuropsychiatric disorders. While the field of biological psychiatry strongly advanced on macroscopic levels, current developments are rediscovering the richness of immunohistological information when attempting a multi-level systematic approach to brain function and dysfunction. For most studies, histology sections lost information on three-dimensional reconstructions. Translating histological sections to 3D-volumes would thus not only allow for multi-stain and multi-subject alignment in post mortem data, but also provide a crucial step in big data initiatives involving the network analyses currently performed with in vivo MRI. We therefore investigated potential pitfalls during integration of MR and histological information where no additional blockface information is available. We demonstrated that strengths and requirements from both methods can be effectively combined at a spatial resolution of 200 μm. However, the success of this approach is heavily dependent on choices of hardware, sequence and reconstruction. We provide a fully automated pipeline that optimizes histological 3D reconstructions, providing a potentially powerful solution not only for primary human post mortem research institutions in neuropsychiatric research, but also to help alleviate the massive workloads in neuroanatomical atlas initiatives. We further demonstrate (for the first time) the feasibility and quality of ultra-high spatial resolution (150 μm isotopic) imaging of the entire human brain MRI at 7T, offering new opportunities for analyses on MR-derived information.
26 citations
TL;DR: A predictive method that allows reliable blood–brain barrier permeability estimation within standard acquisition time, minimizing the likelihood of motion artefacts thereby improving image quality and reducing radiation dose is developed.
23 citations
TL;DR: In a genetic epilepsy model that is both seizure-naive and carries an allele for febrile seizure susceptibility, hippocampal structural changes that may be applied as a biomarker for seizure susceptibility are determined.
Abstract: Objective: The human γ-aminobutyric acid type A (GABA A )γ2 R43Q (R43Q) mutation is associated with genetic epilepsy with febrile seizures. R43Q mice in the C57Bl/6J background do not display spontaneous seizures, but are significantly more susceptible to hyperthermic seizures, providing a model with enhanced seizure susceptibility without the confounding influence of ongoing epileptic activity. Because of GABA9s role in brain development, we sought to determine whether the R43Q mutation alters brain structure before the appearance of seizures. Methods: We used 16.4-tesla, high-field MRI to determine the volumes of hippocampal subregions. Histologic analysis of the same brains allowed stereology-based estimates of neuron counts to be obtained in CA1–3 and the dentate gyrus. Results: Morphologic changes were evident in seizure-naive hippocampi of susceptible mice. Dentate granule cell MRI determined that volume was 5% greater in R43Q mice compared with controls (0.628 mm 3 , 95% confidence interval [CI] 0.611–0.645 vs 0.595 mm 3 , 95% CI 0.571–0.619). The dentate granule cell density was 30% higher in R43Q compared with control mice (553 × 10 3 cells/mm 3 , 95% CI 489–616 vs 427 × 10 3 cells/mm 3 , 95% CI 362–491). Conclusions: In a genetic epilepsy model that is both seizure-naive and carries an allele for febrile seizure susceptibility, we have determined hippocampal structural changes that may be applied as a biomarker for seizure susceptibility.
22 citations
TL;DR: The morphology of the corpus callosum, the largest white matter bundle in the brain, is investigated in an adolescent sample of inhalant users to represent the early stages of neurobiological damage associated with chronic inhalant misuse.
Abstract: Inhalants, frequently abused during adolescence, are neurotoxic to white matter. We investigated the impact of inhalant misuse on the morphology of the corpus callosum (CC), the largest white matter bundle in the brain, in an adolescent sample of inhalant users [n = 14; mean age = 17.3; standard deviation (SD) = 1.7], cannabis users (n = 11; mean age = 19.7; SD = 1.7) and community controls (n = 9; mean age = 19.5; SD = 2.6). We identified significant morphological differences in the CC among inhalant users compared with community controls. There were no morphological differences between inhalant and cannabis users. Our findings may represent the early stages of neurobiological damage associated with chronic inhalant misuse.
18 citations
TL;DR: Novel evidence that the callosal area was smaller in left-handed participants with Williams syndrome than their right-handed counterparts is found, which may be associated with LIM-kinase hemizygosity, a characteristic of Williams syndrome.
Abstract: Williams syndrome is a neurodevelopmental genetic disorder caused by a hemizygous deletion on chromosome 7q11.23, resulting in atypical brain structure and function, including abnormal morphology of the corpus callosum. An influence of handedness on the size of the corpus callosum has been observed in studies of typical individuals, but handedness has not been taken into account in studies of callosal morphology in Williams syndrome. We hypothesized that callosal area is smaller and the size of the splenium and isthmus is reduced in individuals with Williams syndrome compared to healthy controls, and examined age, sex, and handedness effects on corpus callosal area. Structural magnetic resonance imaging scans were obtained on 25 individuals with Williams syndrome (18 right-handed, 7 left-handed) and 25 matched controls. We found that callosal thickness was significantly reduced in the splenium of Williams syndrome individuals compared to controls. We also found novel evidence that the callosal area was smaller in left-handed participants with Williams syndrome than their right-handed counterparts, with opposite findings observed in the control group. This novel finding may be associated with LIM-kinase hemizygosity, a characteristic of Williams syndrome. The findings may have significant clinical implications in future explorations of the Williams syndrome cognitive phenotype.
11 citations
TL;DR: A novel method of integrating the information from MRI and PET emission data to increase the tissue classification accuracy was proposed and it was found that the inclusion of PET data improved the classifier's performance in terms of classification accuracy and PET image reconstruction quality.
Abstract: Photon attenuation correction is a challenging task in the emerging hybrid PET/MRI medical imaging techniques because of the missing link between tissue attenuation coefficient and MRI signal. MRI-based tissue classification methods for attenuation correction have difficulties caused by the significantly different abilities of photon absorption in tissues with similar MRI signal, such as bone and air. We proposed a novel method of integrating the information from MRI and PET emission data to increase the tissue classification accuracy. A classifier based on conditional random field was trained using features extracted from fused MRI and uncorrected PET images. The efficacy of the proposed method was validated quantitatively on synthetic datasets. It was found that the inclusion of PET data improved the classifier’s performance in terms of classification accuracy and PET image reconstruction quality.
9 citations
TL;DR: Investigation of gray and white matter differences between blind and sighted individuals found differences in gray, but not white, matter volumes in various brain regions, providing evidence for structural alterations in the mature brain.
8 citations
TL;DR: The authors demonstrate that a glass vial with flat bottom and 10 ml volume is the best structure to achieve the highest signal out of samples studied and demonstrates the importance of taking into account the combined effects of sensor configuration and sample parameters for signal generation prior to designing and constructing ULF systems with a single-axis magnetometer.
Abstract: Purpose: This paper investigates optimal placement of a localized single-axis magnetometer for ultralow field (ULF) relaxometry in view of various sample shapes and sizes. Methods: The authors used finite element method for the numerical analysis to determine the sample magnetic field environment and evaluate the optimal location of the single-axis magnetometer. Results: Given the different samples, the authors analysed the magnetic field distribution around the sample and determined the optimal orientation and possible positions of the sensor to maximize signal strength, that is, the power of the free induction decay. The authors demonstrate that a glass vial with flat bottom and 10 ml volume is the best structure to achieve the highest signal out of samples studied. Conclusions: This paper demonstrates the importance of taking into account the combined effects of sensor configuration and sample parameters for signal generation prior to designing and constructing ULF systems with a single-axis magnetometer. Through numerical simulations the authors were able to optimize structural parameters, such as sample shape and size, sensor orientation and location, to maximize the measured signal in ultralow field relaxometry.
7 citations
TL;DR: In this paper, the synthesis and spectroscopic characterization of four new 2-(4-aminophenyl)benzothiazole substituted 1,4,7-triazacyclononane derivatives with and without appended pyridyl groups on the macrocycle is reported.
TL;DR: In this paper, the authors measured performance on the Austin maze in patients with unilateral left and right temporal lobe epilepsy (TLE), with and without hippocampal sclerosis, compared to healthy controls.
TL;DR: Compared the efficacy of three machine learning algorithms: neural network, support vector machine and conditional random field to decode the visual stimuli or neural cognitive states from functional Magnetic Resonance data showed comparable performance and the potential of the latter is worthy of further investigation.
Abstract: Brain decoding of functional Magnetic Resonance Imaging data is a pattern analysis task that links brain activity patterns to the experimental conditions. Classifiers predict the neural states from the spatial and temporal pattern of brain activity extracted from multiple voxels in the functional images in a certain period of time. The prediction results offer insight into the nature of neural representations and cognitive mechanisms and the classification accuracy determines our confidence in understanding the relationship between brain activity and stimuli. In this paper, we compared the efficacy of three machine learning algorithms: neural network, support vector machines, and conditional random field to decode the visual stimuli or neural cognitive states from functional Magnetic Resonance data. Leave-one-out cross validation was performed to quantify the generalization accuracy of each algorithm on unseen data. The results indicated support vector machine and conditional random field have comparable performance and the potential of the latter is worthy of further investigation.