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  • Eye movements  (3)
  • Biochemistry and Biotechnology  (2)
  • Cat  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Otolithic-acoustic interaction in the control of eye movement (1979)
    Springer
    Experimental brain research 36 (1979), S. 509-522 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Acoustic ; Vestibular ; Otoliths ; Eye movements ; Linear acceleration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In order to examine otolithic contribution to eye movements ten subjects were asked to track either a moving acoustic target or a stationary target during subect linear motion on a cart. The relative displacement between the subject and the target was the same in the two situations. Recordings of eye movements during subject lateral acceleration in the dark without any task, or with the task of tracking an imagined stationary target were made as a control. The frequencies ranged between 0.15 and 0.3 Hz and peak acceleration between 0.55 and 1.2 m/s2. No lateral eye movements (L-nystagmus) were recorded in the dark. Only saccadic eye movements were recorded during the tracking of a moving acoustic target. Slow eye movements interspersed by saccades were observed when the moving subject tracked an imagined or an acoustic stationary target. Contribution of the slow phase to tracking was more important in the presence of an acoustic target than in the presence of imagined target. The results are interpreted in terms of an otolithic contribution to the central reconstruction of the acoustic target velocity, or in terms of an adaptive control of the otolithic-ocular reflex gain. A conceptual model accounting for these interpretations is proposed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238519
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  • 2
    Digitale Medien
    Digitale Medien
    Influence of otolithic stimulation by horizontal linear acceleration on optokinetic nystagmus and visual motion perception (1980)
    Springer
    Experimental brain research 39 (1980), S. 165-176 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibular system ; Optokinetic ; Otoliths ; Eye movements ; Motion perception
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Several studies in the past have demonstrated the existence of an Otolith-Ocular Reflex (OOR) in man, although much less sensitive than canal ocular reflex. The present paper 1 confirms these previous results. Nystagmic eye movements (L-nystagmus) appear in the seated subject during horizontal acceleration along the interaural axis in the dark for an acceleration level (1 m/s2) about ten times the perception threshold with a sensitivity of about 0.035 rad/m. When sinusoidal linear acceleration is combined with optokinetic stimulation, the recorded nystagmus slow phase velocity exhibits strong periodic modulation related to subject motion. This marked effect of linear acceleration on the optokinetic nystagmus (OKN) appears at a level (0.1 m/s2) close to the acceleration perception threshold and has a 4-fold higher sensitivity than L-nystagmus. Modulation of OKN can reach a peak-to-peak amplitude as great as 20 °/s; for a given optokinetic field size it increases with the velocity of the optokinetic stimulus, i.e. with the slow phase eye velocity. In parallel with changes in OKN slow phase velocity, linear acceleration induces a motion related decrease in the perceived velocity of the visual scene and modifications in selfmotion perception. The results are interpreted in terms of a mathematical model of visual-vestibular interaction. They show that sensory interaction processes can magnify the contribution given to the control of eye movements by the otolithic system and provide a way of exploring its function at low levels of acceleration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237547
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  • 3
    Digitale Medien
    Digitale Medien
    Unidirectional habituation of vestibulo-ocular responses by repeated rotational or optokinetic stimulations in the cat (1981)
    Springer
    Experimental brain research 42 (1981), S. 34-42 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibulo-ocular reflex ; Optokinetic nystagmus ; Vestibular habituation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1.Unilateral habituation of the vestibuloocular reflex was produced in adult cats stimulated by repeated unidirectional velocity steps (vestibular training) or by a continuously moving visual surround (optokinetic training). — 2. Unidirectional vestibular training produced a strong asymmetry of vestibuloocular responses (VOR). Responses to velocity steps applied to the “trained” labyrinth were decreased both in gain and in time-constant. This effect generalized to responses to sinusoidal oscillations (0.03 Hz to 0.1 Hz), i.e. to a stimulus not used during training. — No spontaneous nystagmus was ever observed in spite of the dynamic VOR asymmetry. — 3. Unilateral vestibular habituation produced by vestibular training appeared to be a long-lasting phenomenon. It was still present 10 days after the end of training. — 4. Optokinetic responses were not affected by vestibular training. — 5. Unidirectional optokinetic training produced an increase in the slow phase velocity of optokinetic nystagmus (OKN) by about 25% in both directions. This effect did not persist for more than a few minutes. A marked spontaneous nystagmus was recorded in the dark after each session of optokinetic training, with a slow phase in the direction opposite to the previous OKN. — 6. VOR in response to velocity steps and to sinusoidal oscillations were decreased unilaterally after optokinetic training. This effect was of short duration, however, and disappeared within the interval between training sessions. This lack of retention contrasted with the prolonged effect of vestibular training.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235726
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  • 4
    Digitale Medien
    Digitale Medien
    The role of vision in compensation of vestibulo ocular reflex after hemilabyrinthectomy in the cat (1977)
    Springer
    Experimental brain research 28 (1977), S. 235-248 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibulo-ocular reflex ; Hemilabyrinthectomy ; Role of vision ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. A new description of vestibulo-ocular responses to angular velocity steps has been used to quantify vestibular compensation in right hemilabyrinthectomized cats. The amplitudes (VM and CM) and the times of occurrence (tM and to) from stimulus onset of the peaks of slow phase eye velocity and slow cumulative eye position were computed for velocity steps directed towards the lesioned side (clockwise, CW) and towards the intact side (counterclockwise, CCW). In addition, the values of these parameters were corrected from the effects of spontaneous nystagmus, when present. 2. In animals recovering in normal laboratory conditions, spontaneous nystagmus disappeared within 10 days after operation. In CCW responses, vm decreased by about 45% during the first 3 days and then remained stationary during the next 2 weeks. In CW responses VM showed a rapid increase during the first 3 days, and then remained stationary. After 2 weeks, VM increased in both CW and CCW responses. CM changes substantially reproduced those of VM. 3. In animals put in the dark immediately after operation, spontaneous nystagmus persisted until re-exposure to light (up to 31 days) and then disappeared rapidly. VM in both CW and CCW responses remained at a low value during the dark period and became more or less doubled after one week of exposure to light. CM also increased rapidly in CW and CCW responses, after re-exposure to light. 4. In the discussion these results are compared with those concerning activity of single vestibular neurons during compensation. It is concluded that vision is a primary factor conditioning disinhibition of vestibular nuclei spontaneous activity after the critical phase of compensation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235706
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  • 5
    Digitale Medien
    Digitale Medien
    On-line monitoring of monoclonal antibodies in animal cell culture using a grating coupler (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 1287-1292 
    Details
    ISSN: 0006-3592
    Schlagwort(e): integrated optics ; grating coupler ; FIA ; on-line monitoring ; animal cell culture ; monoclonal antibody ; immunochemical sensor ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A grating coupler was used for the on-line determination of monoclonal antibodies produced in perfused animal cell bioreactor. The device was connected with the culture vessel via a flow-injection analysis (FIA) system, which was controlled automatically. Specific antimouse lgG antibodies were immobilized on the surface of the sensor-chip. After injection of the sample, the binding of mouse lgG was observed in real time. The regeneration of the binding sites of the immobilized antibodies using an acidic solution allowed the on-line detection of produced monoclonal antibodies in the range of 10 to 150 μg/mL. In contrast to other techniques coupled to bioprocesses, the developed method represents a regenerable direct immunosensor. Results were compared with standard ELISA techniques (off-line) and a competitive immunochemical assay using the grating coupler (off-line). © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bit.260421105
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  • 6
    Digitale Medien
    Digitale Medien
    Influence of smooth pursuit dynamics on eye tracking: a mathematical approach (1989)
    Springer
    Medical & biological engineering & computing 27 (1989), S. 617-622 
    Details
    ISSN: 1741-0444
    Schlagwort(e): Dynamics ; Eye movements ; Nonlinear gain ; Smooth pursuit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02441644
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  • 7
    Digitale Medien
    Digitale Medien
    Monosized, magnetic polymer particles: Their use in separation of cells and subcellular components, and in the study of lymphocyte function in vitro (1988)
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 1 (1988), S. 9-18 
    Details
    ISSN: 0952-3499
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: By employing the principles of “activated swelling”, monosized, superparamagnetic polymer particles have been prepared ranging in size from 1-100 μm. Both during and after the swelling process, the particles can be modified to meet a series of specific demands making them potentially very interesting for many separation and assay purposes.Using monoclonal antibodies to direct the magnetic beads to their targets, immunomagnetic separation has turned out to be one of the most specific, reliable and, above all, the fastest technique available today to isolate particulate material for further studies. So far, most efforts have been concentrated on methodology for fractionation of cells in suspension, such as removal of tumour cells from bone marrow or isolation of lymphoid cells from peripheral blood. These studies have both established the parameters necessary for optimal performance and at the same time laid the groundwork for future developments making immunomagnetic separation an exciting new tool in many research areas.High speed and specificity are the most conspicuous features of immunomagnetic cell separation. These properties have been exploited in the successful development of a new technique for tissue typing of cells directly from peripheral blood specimens. Both higher sensitivity and specificity have been obtained. The same principles can be used for fast and safe quantification of cell populations and subpopulations in blood and cell suspensions.The functions of, and interactions between, peripheral blood cell populations or subpopulations in the immune response have also been studied with high precision. The significance of direct cell contact on the one hand, and soluble factors on the other, can now be established in detail. Immunomagnetic beads have also been used to study the interaction between various T lymphocyte membrane molecules in the early phases of the activation process.Finally, the usefulness of specially developed particles for the fractionation of subcellular components is described.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmr.300010104
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