Christoph Hollnagel

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Little is known about the impact of supraspinal centers on the control of human locomotion. Analyzing brain activity can help to clarify their impact and to improve the effects of locomotor training. A fMRI-compatible pneumatic robotic device is presented that can generate freely programmable, highly repetitive periodic active and passive leg movements(More)
Conditions simulating changes during physical exercise were induced in erythrocytes to determine the resulting Bohr effect. Lactic acid was added to red cell suspensions and whole blood with initial 25 and 60% SO2, at 42 Torr PCO2, and temperatures of 20 and 37 degrees C. Changes in pH, PO2 and SO2 were measured. CO2 liberation from buffering lactic acid in(More)
In this work, we studied human head motions during upper extremity motor task, conducted in functional magnetic resonance imaging (fMRI) studies. The experiments were performed on a mock up of the MRI bench. Three kinds of linear movements in the caudal-cranial, left-right and anterior-posterior directions, a reaching movement as well as single joint(More)
Pneumatics is one of the few actuation principles that can be used in an MR environment, since it can produce high forces without affecting imaging quality. However, pneumatic control is challenging, due to the air high compliance and cylinders non-linearities. Furthermore, the system’s properties may change for each subject. Here, we present novel control(More)
The goal of robotic therapy is to provoke motor plasticity via the application of robotic training strategies. Although robotic haptic guidance is the commonly used motor-training strategy to reduce performance errors while training, research on motor learning has emphasized that errors are a fundamental neural signal that drives motor adaptation. Thus,(More)
Little is known about the neural correlates underlying the control of highly coordinated bilateral lower limb movements. In this paper we present an fMRI paradigm consisting of balancing a virtual ball rolling on a virtual bar. The subject can control the position of the bar by its lower limbs using the MR-compatible stepper MARCOS. Concurrent visual and(More)
We investigated the feasibility of studying brain responses to controlled arm movements supported by an fMRI-compatible robotic interface. The study can be used in neurorehabilitation to provide insight into the cortical reorganization mechanism after damage to the nervous system, allow a better understanding of therapy-induced recovery and assist the(More)
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