Ulrich Oertel

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Previous electrophysiological studies had found an early anterior negativity often with a maximum over the left hemisphere to correlate with the early detection of an error in the syntactic structure of a sentence. In this paper, the cortical structures involved in such early syntactic parsing processes were localized using MEG. Subjects were presented with(More)
Neuromagnetic fields were recorded from the left cerebral hemisphere of six healthy right-handed subjects under three different conditions: (1) externally triggered rapid voluntary extension and flexion of the right hand, (2) passive extension and flexion of the right hand, and (3) stimulation of the skin of the right index finger by means of air pressure.(More)
We investigated the influence of noise on brain responses to spoken sentences in MEG. Sixteen subjects had to listen to acoustically presented sentences and judge their syntactic correctness. Sentences were either presented on a silent background or with noise. Noise had differential effects on early auditory and syntactic processes. While noise affected(More)
  • Ulrich Oertel, I Thank, Joseph Christy, Allen Hatcher, Lee Mosher
  • 1998
A lamination L embedded in a manifold M is an affine lamination if its lift L to the universal cover˜M of M is a measured lamination and each covering translation multiplies the measure by a factor given by a homomorphism, called the stretch homomorphism, from π 1 (M) to the positive real numbers. There is a method for analyzing precisely the set of affine(More)
Brain processes underlying spoken language comprehension comprise auditory encoding, prosodic analysis and linguistic evaluation. Auditory encoding usually activates both hemispheres while language-specific stages are lateralized: analysis of prosodic cues are right-lateralized while linguistic evaluation is left-lateralized. Here, we investigated to what(More)
Introduction The discovery by M. Gromov of negatively curved metric spaces and groups Gro87] has strongly innuenced geometric topology and combinatorial group theory. Spaces which are negatively curved generalize hyperbolic manifolds, and they share many of the geometric features of hyperbolic manifolds. For example, in a compact, negatively curved space(More)
We propose in this paper a method for studying contact structures in 3-manifolds by means of branched surfaces. We explain what it means for a contact structure to be carried by a branched surface embedded in a 3-manifold. To make the transition from contact structures to branched surfaces, we first define auxiliary objects called σ-confoliations and pure(More)
A contamination in a 3-manifold is an object interpolating between the contact structure and the lamination. Contaminations seem to provide a link between 3-dimensional contact geometry and the classical topology of 3-manifolds, as described in a separate paper [6]. In this paper we deal with contaminations carried by branched surfaces, giving a sufficient(More)