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Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining(More)
We have examined the activity levels produced in various areas of the human occipital cortex in response to various motion stimuli using functional magnetic resonance imaging (fMRI) methods. In addition to standard luminance-defined (first-order) motion, three types of second-order motion were used. The areas examined were the motion area V5 (MT) and the(More)
Based on the principles of echo imaging, we present a method to acquire sufficient data for a 256 X 256 image in from 2 to 40 s. The image contrast is dominated by the transverse relaxation time T2. Sampling all projections for 2D FT image reconstruction in one (or a few) echo trains leads to image artifacts due to the different T2 weighting of the echo.(More)
A spectroscopic MR technique was used to investigate the time course of the MR signal following a single visual stimulus. Gated experiments demonstrate there is an early response (500 ms after stimulus) leading to a reduction of the MR signal by -0.25% (P = 0.02), whereas a slower response (> 1500 ms after stimulus) results in a signal increase of +0.59% (P(More)
Neural correlates of electroencephalographic (EEG) alpha rhythm are poorly understood. Here, we related EEG alpha rhythm in awake humans to blood-oxygen-level-dependent (BOLD) signal change determined by functional magnetic resonance imaging (fMRI). Topographical EEG was recorded simultaneously with fMRI during an open versus closed eyes and an auditory(More)
In this review, the clinical utility of echoplanar techniques in MRI of the brain is discussed. Comparison of high-resolution EPI with SE/turbo-SE shows high image quality of EPI in the supratentorial brain. In the infratentorial region, however, susceptibility artifacts limit image quality. For the assessment of neuronal brain activation utilizing the(More)
The role of dopamine in monitoring negative action outcomes and feedback-based learning was tested in a neuroimaging study in humans grouped according to the dopamine D2 receptor gene polymorphism DRD2-TAQ-IA. In a probabilistic learning task, A1-allele carriers with reduced dopamine D2 receptor densities learned to avoid actions with negative consequences(More)
Probability mapping of connectivity is a powerful tool to determine the fibre structure of white matter in the brain. Probability maps are related to the degree of connectivity to a chosen seed area. In many applications, however, it is necessary to isolate a fibre bundle that connects two areas. A frequently suggested solution is to select curves, which(More)
Current models of attention describe attention not as a homogenous entity but as a set of neural networks whose measurement yields a set of three endophenotypes-alerting, orienting, and executive control. Previous findings revealed different neuroanatomical regions for these subsystems, and data from twin studies indicate differences in their heritability.(More)
In the present study, we identified the most probable trajectories of point-to-point segregated connections between functional attentional centers using a combination of functional magnetic resonance imaging and a novel diffusion tensor imaging-based algorithm for pathway extraction. Cortical regions activated by a visuospatial attention task were(More)