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  • 1
    Electronic Resource
    Electronic Resource
    Electrical stimulation of the posteroventral pallidum influences internally guided saccades in Parkinson’s disease (1998)
    Springer
    Journal of neurology 245 (1998), S. 101-105 
    Details
    ISSN: 1432-1459
    Keywords: Key words Parkinson’s disease ; Anti-saccades ; Memory-guided ; saccades ; Chronic stimulation ; Posteroventral pallidum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chronic electrical stimulation of the posteroventral internal pallidum, a recently developed treatment option in advanced Parkinson’s disease (PD), improves bradykinesia, rigidity and medication-induced dyskinesia. Apart from disturbances of the somatic motor system, PD is also characterized by disturbances of saccadic eye movements with hypometric and delayed internally guided saccades. We examined these internally guided eye movements (memory-guided and anti-task saccades) in a patient with bilaterally implanted stimulation electrodes, when stimulation was turned on and off. The electrical stimulation not only improved the bradykinesia and rigidity, but also the internally guided saccades by shortening the latency of the anti-saccades and increasing the gain of the memory-guided saccades. This finding supports the idea that the oculomotor pathways through the basal ganglia are organized like the somatic motor pathways and that stimulation of the posteroventral pallidum influences both.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004150050186
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  • 2
    Electronic Resource
    Electronic Resource
    Intrasaccadic target steps during the deceleration of primary saccades affect the latency of corrective saccades (1999)
    Springer
    Experimental brain research 129 (1999), S. 161-166 
    Details
    ISSN: 1432-1106
    Keywords: Key words Corrective saccades ; Latency ; Saccadic eye movements ; Saccadic suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This study investigates how visually guided saccades and subsequent corrective saccades are affected by a secondary target step occurring at different times during the primary saccade. Eye movements of human subjects were measured by means of a differential infrared light reflection technique while the subjects performed visually guided saccades to a laser spot in darkness. The target was stepped backward or onward during the targeting saccade. While the intrasaccadic target step did not influence gain, peak velocity or skewness of the primary saccade, it had a significant effect on the subsequent corrective saccade when the secondary target step occurred during the deceleration phase of the primary saccade: the latency of the corrective saccade was significantly increased compared with the one performed under the single-step control condition. This increase also occurred when single target steps were presented randomly intermixed with backward and onward double target steps and even between selected sub-samples of saccades with identical postsaccadic visual error. If the target step occurred early during the primary saccade, the latency of the corrective saccade was not changed. This indicates that visual information sampled during the deceleration phase of a saccade can lead to a cancellation of the normal trigger mode of corrective saccades.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050947
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  • 3
    Electronic Resource
    Electronic Resource
    Neuronal activity in the flocculus of the alert monkey during sinusoidal optokinetic stimulation (1988)
    Springer
    Experimental brain research 70 (1988), S. 134-144 
    Details
    ISSN: 1432-1106
    Keywords: Alert monkey ; Flocculus ; ‘Gaze velocity’ ; Purkinje cells ; Eye movements ; Sinusoidal optokinetic stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Activity of single units was recorded in the flocculus of alert, behaving monkeys during sinusoidal optokinetic (0.02–5.0 Hz), constant velocity optokinetic, vestibular and visual-vestibular conflict stimulation. The maximal stimulus velocity for sinusoidal optokinetic stimulation at different frequencies was 40 deg/s or less (at frequencies above 1 Hz). For an amplitude series at 0.2 Hz, stimulus velocity was varied between ±10 to ±80 deg/s. In one trained monkey activity was also investigated during smooth pursuit eye movements and suppression of the vestibulo-ocular reflex by visual fixation (VOR-supp.). Only neurons which responded to 0.2 Hz (±40 deg/s) optokinetic stimulation were included in the study. 2. The majority of neurons (44 out of 59) were type I Purkinje cells (PCs), which increased their simple spike activity during optokinetic cylinder rotation to the ipsilateral recording side. The responses during other, vestibular related, paradigms allowed all these neurons to be classified as so called ‘gaze velocity’ PCs. Three type II PCs were encountered, which responded similarly, but were only weakly modulated. 3. All type I PCs were modulated at frequencies of sinusoidal optokinetic stimulation between 0.05 and 2.5 Hz. PC's showed little or no modulation at 0.03 and 0.02 Hz. About half of the PC's still responded at 5.0 Hz. 4. Relative to eye velocity, the PC activity had a phase advance of about 30 deg between 0.1 and 2 Hz. It became larger at lower, and smaller at higher, frequencies. Eye velocity related sensitivity (imp/s/deg/s) was small at low stimulus frequencies and increased monotonically, on average from 0.16 at 0.02 Hz to 2.0 at 3.3 Hz. 5. Ten (out of 12) mossy fiber related input neurons were classified as visual neurons, since their activity could be related to the amount of retinal slip in all conditions. Neurons were clearly modulated at sinusoidal optokinetic stimulation up to 5 Hz. One input neuron, investigated during sinusoidal OKN, smooth pursuit eye movements, VOR and VOR-supp., behaved qualitatively like a ‘gaze velocity’ PC. The remaining input neuron encoded eye velocity at 0.2 Hz optokinetic, vestibular and visual-vestibular conflict stimulation. 6. The results show that during sinusoidal and constant velocity optokinetic stimulation ‘gaze velocity’ PC's do not encode eye velocity and/or eye acceleration. 7. The vestibular nuclei-flocculus complementary hypothesis (Waespe and Henn 1981) can explain PC responses to a large extent. However, a direct comparison shows that at low frequencies (particularly around 0.05 Hz) the complementary responses of most ‘velocity storage’ encoding vestibular nuclei neurons and floccular PC's appears insufficient to account fully for the oculomotor response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271855
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  • 4
    Electronic Resource
    Electronic Resource
    Prediction and a stationary, structured visual background influence the dynamics of the smooth-pursuit offset in humans (1998)
    Springer
    Experimental brain research 123 (1998), S. 361-367 
    Details
    ISSN: 1432-1106
    Keywords: Key words Smooth-pursuit termination ; Human ; Prediction ; Structured visual background
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It is still not clear whether the transition from pursuit eye movements to fixation is mediated by the same system that initiates pursuit, or whether another system, a specialized fixation system, is responsible. To investigate this question we measured smooth-pursuit eye movements and smooth-pursuit termination in five normal subjects using both predictable and unpredictable step-ramp stimuli (velocities 10° and 20°/s) in front of a homogeneous and a structured visual background in order to compare the profile of eye velocity under these different conditions. With the predictable and/or structured visual background there was a gradual transition of eye velocity toward zero. In contrast, with the unpredictable stimulus in front of a homogeneous background, eye velocity during the offset was characterized by an overshoot (on the average, 2.2±1.0°/s for 10°/s ramps) before eye velocity settled at zero. Under this condition, steady-state velocity gain and the deceleration of the offset were significantly higher than during the other paradigm with the same target velocity. The latency of the pursuit offset was significantly shorter when a predictable stimulus was used. The duration of the offset did not depend on the experimental condition used. These findings imply that the pursuit onset and offset have some similarities and may be mediated by the same oculomotor system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050581
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  • 5
    Electronic Resource
    Electronic Resource
    Oculomotor Effects of γ-Aminobutyric Acid Agonists and Antagonists in the Vestibular Nuclei of the Alert Monkey (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 656 (1992), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1992.tb25242.x
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  • 6
    Electronic Resource
    Electronic Resource
    Recovery of ChAT lmmunoreactivity in Axotomized Rat Cholinergic Septal Neurons Despite Reduced NGF Receptor Expression (1997)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 9 (1997), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Previous studies have suggested that target-derived nerve growth factor (NGF) is essential for the survival of cholinergic basal forebrain neurons. Thus, axotomy of septohippocampal neurons in adult rats resulting in the withdrawal of target-derived NGF caused a dramatic loss of choline acetyltransferase (ChAT)-immunoreactive neurons in the medial septum-diagonal band complex. We have recently shown that this loss of immunolabelled neurons does not indicate cell death, since many septohippocampal cholinergic neurons recover their immunoreactivity for ChAT after a long survival time despite disconnection from target-derived neurotrophins. One possibility would be that these surviving ChAT-immunoreactive neurons have gained access to other, probably local, NGF sources. Here we provide evidence that the recovery of ChAT immunoreactivity after axotomy is not accompanied by a similar recovery of NGF receptor expression in these neurons. In situ hybridization for p75NTR mRNA and trkA mRNA 6 months after bilateral fimbria-fornix transection revealed a substantial loss of labelled cells. In addition, there was a persisting loss of p75NTR-immunoreactive and NGF-immunoreactive medial septal neurons. Cholinergic neurons in controls did not express NGF mRNA, but were heavily immunostained for NGF protein due to receptor-mediated uptake. These data suggest that at least some cholinergic septohippocampal neurons re-express ChAT either independently of NGF or with a reduced need for NGF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1997.tb01488.x
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  • 7
    Electronic Resource
    Electronic Resource
    Opsoklonus und Ocular flutter (1997)
    Springer
    Der Nervenarzt 68 (1997), S. 633-637 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Augenbewegung ; Ocular flutter ; Opsoklonus ; Key words Eye movement ; Ocular flutter ; Opsoclonus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Ocular flutter is an ocular motor disorder consisting of involuntary back-to-back saccades in the horizontal plane without a saccadic interval. In opsoclonus, these pathological eye movements occur not only in the horizontal but also in the vertical plane. Originally, opsoclonus was described as irregular, conjugate, chaotic and partially continuous rapid eye movements. In this review, the clinical picture, differential diagnosis, etiology, natural course and therapeutic concepts for these eye movement disorders are described. It is stressed that continuous and intermittent forms of opsoclonus can be distinguished and that these differences usually correlate with the severity of the underlying disease. In contrast, the intermittent forms of opsoclonus and ocular flutter are usually only distinguished by the lack of a vertical eye movement component in ocular flutter.
    Notes: Zusammenfassung Ocular flutter ist definiert als eine Serie von unwillkürlichen hin- und herspringenden raschen Augenbewegungen (Sakkaden), die ohne sakkadisches Intervall ausschließlich in der horizontalen Ebene auftreten. Beim Opsoklonus treten die pathologischen Augenbewegungen nicht nur in der horizontalen, sondern auch in der vertikalen Ebene auf. Ursprünglich [43] beschrieb der Ausdruck Opsoklonus unregelmäßige, konjugierte, chaotische und z.T. kontinuierliche rasche Augenbewegungen. Einige gesunde Personen können Opsoklonus auch willkürlich auslösen [63]. Im folgenden sollen das klinische Bild, Differentialdiagnosen, Ätiologie, Verlauf und Therapie dieser Augenbewegungsstörungen besprochen werden. Hervorgehoben wird, daß beim Opsoklonus kontinuierliche und intermittierende Formen unterschieden werden können, was gewöhnlich mit der Schwere der Grunderkrankung korreliert. Dagegen unterscheiden sich intermittierende Formen des Opsoklonus und Ocular flutter häufig nur durch das Fehlen einer vertikalen Komponente beim letzteren.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050173
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  • 8
    Electronic Resource
    Electronic Resource
    Ungewöhnliche Kombination einer Karotis-Sinus-cavernosus-Fistel und Sinusthrombose Erfolgreiche Therapie durch Antikoagulation (1997)
    Springer
    Der Nervenarzt 68 (1997), S. 135-138 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Karotis-Sinus-cavernosus-Fistel ; Antikoagulation ; Venenthrombose ; Venöser Infarkt ; A-V-Malformation ; Key words Carotid cavernous fistula ; Anticoagulation ; Venous thrombosis ; Venous infarct ; A-V malformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Dural carotid cavernous fistulas (DCCF) can be associated with venous thrombosis. We report on a rare case of a patient who developed a venous infarct, which was diagnosed on CT and MRI. The DCCF predominantly drained through a frontobasal cortical vein into the superior sagittal sinus. The shunt volume was small and was therefore thought not to be sufficient to explain the massive ocular signs, such as severe exophthalmus and reduction of visual acuity. We therefore postulated a venous congestion owing to a secondary spontaneous venous thrombosis of the draining venous pathways to be responsible for the ocular signs. Under anticoagulative medication, the patient's signs and symptoms improved gradually. Control angiography after 3 months showed that the DCCF had disappeared. In the presence of DCCF, anticoagulation should always be considered when a venous thrombosis is suspected.
    Notes: Zusammenfassung Durale Karotis-Sinus-cavernosus-Fisteln (DCCF) können mit einer Venenthrombose vergesellschaftet sein. Wir berichten über 1 Patientin mit einer DCCF, die einen ausgedehnten venösen Infarkt entwickelte. Die Drainage der DCCF erfolgte überwiegend über eine frontobasale Vene in den Sinus sagittalis superior. Das geringe Shuntvolumen der DCCF konnte die ausgeprägte okulare Symptomatik mit deutlichem Exophthalmus und erheblicher sekundärer Visusverschlechterung nicht erklären. Daher gingen wir von einer spontanen Thrombose im Bereich der Drainagewege der DCCF aus und haben die Patientin antikoaguliert. Unter dieser Therapie bildeten sich Exophthalmus und Visusstörung rasch zurück. In der Kontrollangiographie nach 3 Monaten war die DCCF nicht mehr nachweisbar. Eine Antikoagulation sollte bei vorliegender DCCF immer dann erwogen werden, wenn eine ausgeprägte venöse Thrombose vermutet wird.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050108
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  • 9
    Electronic Resource
    Electronic Resource
    Atheromeinblutung Eine kernspintomographische Differentialdiagnose zur Dissektion der Arteria carotis (1997)
    Springer
    Der Nervenarzt 68 (1997), S. 671-673 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Dissektion ; Intramurales Hämatom ; Atherom ; Therapie ; Key words Dissection ; Intramural hematoma ; Atheroma ; Therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Improved methods of imaging the cerebral vascular system have increased the detection of traumatic or spontaneous dissection of the vertebral and carotid arteries. Especially MRI allows direct demonstration of intramural hematomas that are a sign of dissection of the vessel wall. We report on a patient who had an acute onset of dysarthria and monocular blurred vision, which recurred several times. Doppler ultrasound showed stenosis in both internal carotid arteries with reduced velocity of the flow; angiography confirmed the stenosis, showing a long stretch of stenosis (70%) of the right and a short stretch of stenosis (60%) of the left internal carotid arteries. MRI demonstrated a narrowing of the lumen by an intramural mass, whose signal characteristics were typical for blood. The MRI findings were thus consistent with the diagnosis of a spontaneous dissection of the carotid arteries. Since the Doppler ultrasound follow-up showed no change during the following 3 days, we interpreted the MRI findings as an indication of bleeding in an atheroma. The carotid disobliteration, performed first on the left side and later on the right side, confirmed this interpretation. Since stenosis due to a fissuring atheroma or bleeding in an atheroma requires different therapy than a dissection, it is thus important to consider the possible differential diagnosis in interpreting the MRI.
    Notes: Zusammenfassung Durch die Fortschritte in den bildgebenden Verfahren werden traumatische, bzw. spontane Dissektionen der A. carotis und der A. vertebralis zunehmend häufiger diagnostiziert. Insbesondere die Magnetresonanztomographie ermöglicht dabei einen direkten Nachweis von intramuralen Hämatomen als Zeichen der Dissektion. Wir berichten nun über einen Patienten, der akut beginnend und im Verlauf rezidivierend eine Dysarthrie sowie monokuläre Sehstörungen des linken Auges bemerkte. Dopplersonographisch fand sich beidseits, rechts betont, eine im Bulbus der A. carotis communis beginnende, bis in die A. carotis interna reichende Stenose, in der arteriellen digitalen Subtraktionsangiographie eine langstreckige etwa 70%ige A.-carotis-interna-Stenose rechts und eine kurzstreckige etwa 60%ige Stenose links. Diese Befunde ließen sowohl an eine ausgeprägte arteriosklerotische Makroangiopathie als auch an eine Dissektion denken. In der Kernspintomographie fand sich dann eine verdickte Gefäßwand der A. carotis interna beidseits mit einem schmalen Restlumen. Dieses wurde beidseits von in der T1w-Gewichtung mit selektiver Fettunterdrückung hyperintensivem Gewebe, am ehesten einem intramuralen Hämatom entsprechend, eingeengt. Dieser Befund ließ dann an eine beidseitige Dissektion der A. carotis interna denken. Auf Grund der in der Duplexsonographie über Tage unveränderten Befunde wurde das Bild dann als eine Einblutung in Wandatherome beidseits bei arteriosklerotischer Makroangiopathie gewertet und der Patient wegen der rezidivierenden, hämodynamisch bedingten Symptomatik operiert. Bei der zweizeitig durchgeführten Karotisdesobliteration beidseits bestätigte sich der Verdacht auf intramurale Atherome. Intramurale Atherome mit oder ohne Einblutung sind eine kernspintomographische Differentialdiagnose zu intramuralen Hämatomen bei Karotisdissektion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050180
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  • 10
    Electronic Resource
    Electronic Resource
    Seltene Kopfschmerzsyndrome¶SUNCT-Syndrom, Hemicrania continua und das Syndrom vom roten Ohr (1999)
    Springer
    Der Nervenarzt 70 (1999), S. 754-758 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter SUNCT-Syndrom ; Hemicrania continua ; Syndrom des roten Ohres ; Kopfschmerzpathophysiologie ; Key words SUNCT syndrome ; Hemicrania continua ; Red ear syndrome ; headache-pathophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Rare headache syndromes that are so fare not yet admitted to the classification system of the International Headache Society are the SUNCT syndrome (short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing), the hemicrania continua and the red ear syndrome. The clinical characteristics, differential diagnoses and therapeutic strategies of these pathophysiologically unclarified diseases are presented with three casuistic reports.
    Notes: Zusammenfassung Zu den seltenen Kopfschmerzsyndromen, die bislang nicht in die internationale Kopfschmerzklassifikation aufgenommen wurden, zählen u.a. das SUNCT-Syndrom (“short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing”), die Hemicania continua und das Syndrom des roten Ohres. Die klinischen Charakteristika, Differentialdiagnosen und die therapeutischen Optionen dieser pathophysiologisch bislang nicht verstandenen Syndrome werden anhand von 3 Kasuistiken vorgestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050507
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