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Several tracing studies have established a topographical distribution of fiber connections to the cortex in midsagittal cross-sections of the corpus callosum (CC). The most prominent example is Witelson's scheme, which defines five vertical partitions mainly based on primate data. Conventional MRI of the human CC does not reveal morphologically discernable(More)
Changes in cerebral blood oxygenation due to functional activation of the primary sensorimotor cortex during a unilateral finger opposition task were simultaneously mapped by deoxyhemoglobin-sensitive magnetic resonance imaging (MRI) and monitored by near-infrared spectroscopy (NIRS). Activation foci along the contralateral central sulcus displayed(More)
Fine-scale functional organization of the finger areas in the human primary somatosensory cortex was investigated by high-resolution BOLD MRI at 3 T using a multi-echo FLASH sequence with a voxel size of 2 mm(3). In six subjects independent tactile stimulation of the distal phalanx of the fingers of the right hand resulted in small circumscribed and barely(More)
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)
The regional distribution of brain metabolites was studied in several cortical white and gray matter areas, cerebellum, and thalamus of young adults with use of quantitative single-voxel proton MRS at 2.0 T. Whereas the neuronal compound N-acetylaspartate is distributed homogeneously throughout the brain, N-acetylaspartylglutamate increases caudally and(More)
Changes in glucose consumption, lactate production, and blood oxygenation were measured during prolonged neuronal activation (4-6 min) in human primary visual cortex using dynamic magnetic resonance spectroscopy and imaging. A decrease of steady-state glucose by 40% because of enhanced use by 21% was accompanied by a transient accumulation of lactate with a(More)
To elucidate changes in human brain activity evoked by repetitive transcranial magnetic stimulation (rTMS), sub- and suprathreshold rTMS (4 Hz, 10 s) over the left primary sensorimotor cortex (M1/S1) was interleaved with blood-oxygenation-level-dependent (BOLD) echo-planar imaging of primary and secondary motor areas. Suprathreshold rTMS over left M1/S1(More)
Stimulus-related signal changes in functional MRI of human brain activation not only reflect associated adjustments of cerebral blood flow and oxygen consumption, but strongly depend on the MRI technique chosen and the actual experimental setting. A list of relevant parameters includes static field homogeneity of the magnet, MR pulse sequence and signal(More)
The effects of repetitive transcranial magnetic stimulation (rTMS) on human brain activity and associated hemodynamics were investigated by blood-oxygenation-level-dependent (BOLD) MRI using echo-planar imaging at 2.0 T. Apart from bilateral activation of the auditory cortex by the audible rTMS discharges (23 bursts, 1 s duration, 10 Hz, 10-20 s(More)
Blood oxygenation level dependent (BOLD) MRI was used to monitor modulations of human sensorimotor activity by prior transcranial direct current stimulation (tDCS). Activation maps for a right hand sequential finger opposition task were obtained for six subjects before as well as 0-5 min and 15-20 min after a 5-min period of 1 mA cathodal and, in a separate(More)