Thomas Michaelis

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Stress-induced structural remodeling in the adult hippocampus, involving debranching and shortening of dendrites and suppression of neurogenesis, provides a cellular basis for understanding the impairment of neural plasticity in the human hippocampus in depressive illness. Accordingly, reversal of structural remodeling may be a desirable goal for(More)
In vivo concentrations of cerebral metabolites were obtained by means of 52 single-voxel, localized proton magnetic resonance (MR) spectroscopic examinations of different regions of the brain performed in 26 healthy adults aged 21-32 years. The study was performed at 2.0 T with use of a circularly polarized head coil to ensure homogeneous radio-frequency(More)
This study describes the neuroaxonal tracing of the visual pathway in the living rat using high-resolution T1-weighted 3D gradient-echo MRI (195 x 195 x 125 microm3) at 8, 24, 48, and 72 h after intraocular Mn2+ injection (0.1 microl of 1 M aqueous MnCl2). Best results were obtained at 24 h postinjection, revealing a continuous pattern of anterograde(More)
Oligodendrocytes myelinate axons for rapid impulse conduction and contribute to normal axonal functions in the central nervous system. In multiple sclerosis, demyelination is caused by autoimmune attacks, but the role of oligodendroglial cells in disease progression and axon degeneration is unclear. Here we show that oligodendrocytes harbor peroxisomes(More)
Although magnetic resonance imaging (MRI) represents the most sensitive tool for the detection of white matter abnormalities in patients with multiple sclerosis (MS), the heterogeneity of MS placques severely hampers the elucidation of specific pathophysiological processes. In order to identify putative MRI markers for de- and remyelination, we employed the(More)
This work presents three-dimensional MRI studies of rodent brain in vivo after focal and systemic administration of MnCl2. Particular emphasis is paid to the morphology and dynamics of Mn2+-induced MRI signal enhancements, and the physiological mechanisms underlying cerebral Mn2+ uptake and distribution. It turns out that intravitreal and intrahippocampal(More)
Noninvasive imaging of the brain of animal models demands the detection of increasingly smaller structures by in vivo MRI. The purpose of this work was to elucidate the spatial resolution and structural contrast that can be obtained for studying the brain of C57BL/6J mice by optimized T2-weighted fast spin-echo MRI at 9.4 T. As a prerequisite for(More)
The brain morphology and chemistry of seven children with late infantile (4/7) and juvenile (3/7) forms of metachromatic leukodystrophy (MLD) were investigated by magnetic resonance imaging (MRI) and localized proton magnetic resonance spectroscopy (MRS). Patients who were examined at least 6 months after the onset of symptoms (6/7) had severe(More)
The neuropeptide substance P and its receptor, the neurokinin 1 receptor (NK(1)R) have been proposed as possible targets for new antidepressant therapies. The present study investigated the effect of the NK(1)R antagonist L-760,735 and the tricyclic antidepressant clomipramine in the chronic psychosocial stress paradigm of adult male tree shrews. Animals(More)
This work demonstrates technical approaches to high-quality magnetic resonance imaging (MRI) of small structures of the mouse brain in vivo. It turns out that excellent soft-tissue contrast requires the reduction of partial volume effects by using 3D MRI at high (isotropic) resolution with linear voxel dimensions of about 100-150 microm. The long T(2)*(More)