PD Dr. med. Urs Schwarz

 

Main Goals, Keywords

Investigation of the visual, vestibular and optomotor system in both patients and healthy humans.

Keywords: vision, visual, vestibular, optomotor, eye movements, cortex, magnetic search coil, fMRI, human

Group Members

1 group leader, 1 postdoctoral fellow, 2 doctoral fellows, 1 orthoptist, 1 electronic engineer

Continuing collaboration with PD Dr. rer. nat Uwe Ilg, Tübingen, Germany

Previous and Current Research

• Investigation of neural mechanisms of cortical and subcortical visual motion and visuo-motor transformation processing, which are crucial in establishing and maintaining distinct frames of references needed to guarantee undisturbed goal-directed movements. To study the fundamental principles of conversion and switching between the different visual and motor coordinate systems, most of which take place in parietal and frontal areas, eye movement and fMRI recordings are used in various visuo-optomotor paradigms.
  In particular, our recent research has focused on the question how the smooth pursuit eye movement system (SPEM, typically elicited by a small moving target on a homogeneous background) is able to sustain accurate tracking (local motion) of its object of interest in an enriched visual surroundings, which immediately engages the powerful optokinetic (global motion) system in the opposite direction, hence, threatening the ongoing eye movement to either reverse or come to a complete stop. Employing a newly developed paradigm, we were able to show that initiation of local motion detection via the SPEM system tunes the sensitivity of global motion detectors in anticipation of their activation due to the subsequent retinal slip during tracking (see ref 1/3). This paradigm now is widely used and validated in selected patients with cortical lesions.
  Other ongoing research centers around the question of inter-hemispheric transfer: a variety of experiments, including the anti-saccade, the Poffenberger, and an advanced motion detection paradigm, are used to gain understanding of various callosal transfer mechanisms and decision making processes in normal subjects.
• Investigation and classification of eye movements in normal subjects and a wide range of patients suffering from acute and chronic cortical, subcortical as well as peripheral neurological lesions and deficits: mitochondrial cytopathy, myopathy, myasthenia, neuropathy, amyotrophic lateral sclerosis; multiple sclerosis, infections (in particular, MFS, PML, M. Whipple), cerebrovascular diseases; Parkinsonism, M. Alzheimer and other degenerative disorders, after focal and global head trauma (see ref 4 for a review).
• Development of real-time and off-line software packages for scientific applications (digital signal analysis, digital image processing, pattern recognition, artificial neural networks, and digital simulation) in MATLAB, C++, C, FORTRAN, and assembler language on a variety of processors and operating systems.
• Development of a video display based visual stimulation system as well as a real-time data acquisition and analysis system for small computers.

Future Projects

We will continue to analyze visuo-visual interaction and cortical visuo-motor transformation using near real-world visual stimuli in a variety of newly developed behavioral paradigms in healthy subjects as well as acutely and chronically ill patients.

Techniques and Equipment

State-of-the-art eye movement recording techniques (magnetic search-coil unit in the laboratory) and fMRI recording facilities at the University Hospital of Zurich.

Selected Publications

• Mink, S., Schwarz, U., Mudra, R., Gugl, C., Fröhlich, J., Keller, E. Treatment of Resistant Fever: New Method of Local Cerebral Cooling. Neurocrit Care. Oct 1 (2010).
  
• Schwarz, U., Baumann, K., Ilg, U.J. Influence of global motion onset on goal-directed eye movements. Neuroreport. May 12; 21(7): 479-84 (2010).

Selected Lectures, Seminars or Colloquia

• Clinical Neurology
• Functional Neuroanatomy
• Oto-Neuro-Ophthalmology colloquia

Funding

Swiss National Science Foundation