Franz Schautzer

Ludwig-Maximilian-University of Munich, München, Bavaria, Germany

Are you Franz Schautzer?

Claim your profile

Publications (6)30.79 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In tierexperimentellen Studien konnte die Bedeutung des vestibulären Systems für die Navigation und räumliche Orientierung bereits nachgewiesen werden: Vestibuläre Signale sind z.B. wichtig für die sog. place cells im Hippocampus, die ein neuronales Substrat der räumlichen Repräsentation darstellen. Um die Bedeutung des vestibulären Systems für Navigation und räumliche Orientierung beim Menschen zu untersuchen, haben wir bei 10 Patienten mit kompletter bilateraler Vestibulopathie (beidseitige Neurektomie aufgrund bilateraler Akustikusneurinome bei Neurofibromatose Typ II) a) das räumliche Gedächtnis mittels eines PC adaptieren virtuellen „Morris water task“ (d.h. die Messung erfolgt im Sitzen ohne zusätzliche vestibuläre oder somatosensorische Informationen) getestet, b) andere kognitive und mnestische Funktionen untersucht und c) das Hippocampusvolumen mittels MRT Volumetrie bestimmt; diese Daten wurden mit einer alters-, geschlechts- und IQ-adaptierten Kontrollgruppe verglichen. Die Patienten mit bilateraler Vestibulopathie zeigten sowohl signifikante Defizite des räumlichen Gedächtnisses und der Navigation (ohne weitere zusätzliche neuropsychologische Störungen) als auch eine signifikante Atrophie des Hippocampus (−16.9%). Diese Studie belegt zum einen, dass der Hippocampus eine zentrale Rolle für die räumliche Orientierung und Navigation spielt; dies wird durch andere Studien gestützt, die eine positive Korrelation zwischen der Größe des Hippocampus, Navigationsvermögen und räumlichem Gedächtnis gezeigt haben. Zum anderen lässt sich aus den Befunden schließen, dass ein intaktes vestibuläres System eine Voraussetzung für diese wichtigen Funktionen darstellt.
    12/2007: pages 103-107;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The human hippocampal formation plays a crucial role in various aspects of memory processing. Most literature on the human hippocampus stresses its non-spatial memory functions, but older work in rodents and some other species emphasized the role of the hippocampus in spatial learning and memory as well. A few human studies also point to a direct relation between hippocampal size, navigation and spatial memory. Conversely, the importance of the vestibular system for navigation and spatial memory was until now convincingly demonstrated only in animals. Using magnetic resonance imaging volumetry, we found that patients (n = 10) with acquired chronic bilateral vestibular loss (BVL) develop a significant selective atrophy of the hippocampus (16.9% decrease relative to controls). When tested with a virtual variant (on a PC) of the Morris water task these patients exhibited significant spatial memory and navigation deficits that closely matched the pattern of hippocampal atrophy. These spatial memory deficits were not associated with general memory deficits. The current data on BVL patients and bilateral hippocampal atrophy revive the idea that a major--and probably phylogenetically ancient--function of the archicortical hippocampal tissue is still evident in spatial aspects of memory processing for navigation. Furthermore, these data demonstrate for the first time in humans that spatial navigation critically depends on preserved vestibular function, even when the subjects are stationary, e.g. without any actual vestibular or somatosensory stimulation.
    Brain 12/2005; 128(Pt 11):2732-41. · 9.92 Impact Factor
  • Source
    Neurology 05/2004; 62(7):1228-9. · 8.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The role of the vestibular system for navigation and spatial memory has been demonstrated in animals but not in humans. Vestibular signals are necessary for location-specific "place cell" activity in the hippocampus which provides a putative neural substrate for the spatial representation involved in navigation. To investigate the spatial memory in patients with bilateral vestibular failure due to NF2 with bilateral neurectomy, a virtual variant (on a PC) of the Morris water task adapted to humans was used. Significant spatial learning and memory deficits were shown in 12 patients as compared to 10 healthy controls. These data suggest that functional hippocampal deficits manifest due to a chronic lack of vestibular input in these patients. These deficits can even be demonstrated with the subjects stationary, i.e., without any actual vestibular or somatosensory stimulation.
    Annals of the New York Academy of Sciences 11/2003; 1004:316-24. · 4.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several drugs that primarily act on gamma-aminobutyrate or muscarinic receptors have been used to treat downbeat nystagmus (DBN) syndrome despite their having only moderate success and causing several side effects that limit their effectiveness. These drugs were tested under the assumption that DBN was caused by a disinhibition of a physiologic inhibitory cerebellar input on vestibular nuclei. To evaluate the effects of a single dose of the potassium channel blocker 3,4-diaminopyridine (3,4-DAP), which is known to increase the excitability of Purkinje cells, on DBN in a prospective, placebo-controlled, double-blind study with a crossover design. Seventeen patients with DBN due to cerebellar atrophy (5), infarction (3), Arnold-Chiari malformation (1), or unknown etiology (8) were included in the study (1 of 18 patients had to be excluded). Mean peak slow-phase velocity (PSPV) was measured before and 30 minutes after randomized ingestion of 20 mg of 3,4-DAP or placebo orally; at least 1 week later, the treatments were switched. 3,4-DAP reduced mean PSPV of DBN from 7.2 +/- 4.2 degrees /s (mean +/- SD) before treatment to 3.1 +/- 2.5 degrees/s 30 minutes after ingestion of the 3,4-DAP (p < 0.001, two-way analysis of variance). Placebo had no measurable effect. In 10 of 17 subjects, the mean PSPV decreased by >50% and in 12 of 17 by >40%. In parallel, the subjects had less oscillopsia and felt more stable while standing and walking. Nine of the subjects continued to take the drug with success. Except for transient minor perioral or digital paresthesia reported by three subjects and nausea and headache reported by one, no other side effects were observed. In this study, the authors demonstrated that a single dose of 3,4-DAP significantly improved DBN. In view of animal studies reporting that micromolar concentrations of 4-aminopyridine increased the excitability of Purkinje cells, it is suggested that the efficacy of 3,4-DAP may be due to an increase of the physiologic inhibitory influence of the vestibulocerebellum on the vestibular nuclei.
    Neurology 07/2003; 61(2):165-70. · 8.25 Impact Factor
  • American Journal of Ophthalmology - AMER J OPHTHALMOL. 01/2003; 136(5):971-971.