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Artykuły w czasopismach na temat "Saccades"
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Schnier, Fabian, i Markus Lappe. "Differences in intersaccadic adaptation transfer between inward and outward adaptation". Journal of Neurophysiology 106, nr 3 (wrzesień 2011): 1399–410. http://dx.doi.org/10.1152/jn.00236.2011.
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Saccadic adaptation is a mechanism to increase or decrease the amplitude gain of subsequent saccades, if a saccade is not on target. Recent research has shown that the mechanism of gain increasing, or outward adaptation, and the mechanism of gain decreasing, or inward adaptation, rely on partly different processes. We investigate how outward and inward adaptation of reactive saccades transfer to other types of saccades, namely scanning, overlap, memory-guided, and gap saccades. Previous research has shown that inward adaptation of reactive saccades transfers only partially to these other saccade types, suggesting differences in the control mechanisms between these saccade categories. We show that outward adaptation transfers stronger to scanning and overlap saccades than inward adaptation, and that the strength of transfer depends on the duration for which the saccade target is visible before saccade onset. Furthermore, we show that this transfer is mainly driven by an increase in saccade duration, which is apparent for all saccade categories. Inward adaptation, in contrast, is accompanied by a decrease in duration and in peak velocity, but only the peak velocity decrease transfers from reactive saccades to other saccade categories, i.e., saccadic duration remains constant or even increases for test saccades of the other categories. Our results, therefore, show that duration and peak velocity are independent parameters of saccadic adaptation and that they are differently involved in the transfer of adaptation between saccade categories. Furthermore, our results add evidence that inward and outward adaptation are different processes.
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Dombrowe, Isabel. "Saccadic inhibition in a guided saccade task". PeerJ 6 (14.03.2018): e4493. http://dx.doi.org/10.7717/peerj.4493.
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The eye movement system reacts very systematically to visual transients that are presented during the planning phase of a saccade. About 50 to 70 ms after the onset of a transient, the number of saccades that are started decreases, a phenomenon that has been termed saccadic inhibition. Saccades started just before this time window are hypometric compared to regular saccades, presumably because the presentation of the transient stops them in mid-flight. Recent research investigating the properties of repeated saccades to fixed locations found that these early saccades were additionally faster than expected from the main sequence relation, suggesting that a saccadic dead time during which saccades can no longer be modified does not exist. The present study investigated the properties of saccades to random locations in a guided saccade task. As expected, early saccades starting just before the saccadic inhibition dip in frequency were hypometric. Their velocity profiles implied that these saccades were actively stopped after reaching peak velocity. However, the peak velocities of these saccades did not generally deviate from the main sequence relation. The question whether an active stop of early saccades is incompatible with the idea of a saccadic dead time is open to debate.
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Awater, Holger, i Markus Lappe. "Perception of Visual Space at the Time of Pro- and Anti-Saccades". Journal of Neurophysiology 91, nr 6 (czerwiec 2004): 2457–64. http://dx.doi.org/10.1152/jn.00821.2003.
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The localization of peri-saccadically flashed objects shows two types of errors: first, a uniform shift in saccade direction, and second, a compression of visual space around the saccade target. Whereas the uniform shift occurs when the experiment is performed in complete darkness compression occurs when additional visual references are available. Thus peri-saccadic mislocalization contains motor and visual components. To distinguish between both factors we compared peri-saccadic localization errors during pro- and anti-saccades. In the case of anti-saccades, the visual cue that elicits the saccade and the actual eye movement are in opposite directions. We asked whether peri-saccadic compression can be observed with anti-saccades, and if so, whether the compression is directed toward the visual cue or follows the actual eye movement. In blocked trials, subjects performed saccades either toward a visual cue (pro-saccade) or to the mirrored position opposite to a visual cue (anti-saccade). Peri-saccadically, we flashed a thin vertical bar at one of four possible locations. Subjects had to indicate the perceived position of the bar with a mouse pointer about 500 ms after the saccade. Experiments were performed in complete darkness and with visual references. Peri-saccadic mislocalizations occurred during anti-saccades. The mislocalizations were very similar for pro- and anti-saccades in magnitude and direction. For both, pro- and anti-saccades, mislocalizations were directed toward the actual eye movement and not the visual cue.
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Handel, Ari, i Paul W. Glimcher. "Contextual Modulation of Substantia Nigra Pars Reticulata Neurons". Journal of Neurophysiology 83, nr 5 (1.05.2000): 3042–48. http://dx.doi.org/10.1152/jn.2000.83.5.3042.
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Neurons in the substantia nigra pars reticulata (SNr) are known to encode saccadic eye movements within some, but not all, behavioral contexts. However, the precise contextual factors that effect the modulations of nigral activity are still uncertain. To further examine the effect of behavioral context on the SNr, we recorded the activity of 72 neurons while monkeys made saccades during a delayed saccade task and during periods of free viewing. We quantified and compared the movement fields of each neuron for saccades made under three different conditions: 1) spontaneous saccades, which shifted gaze during periods of free viewing when no stimuli were presented and no reinforcements were delivered; 2) fixational saccades, which brought gaze into alignment with a fixation target at the start of a delayed saccade trial, were necessary for trial completion, but were not directly followed by reinforcement; and 3) terminal saccades, which brought gaze into alignment with a visual target at the end of a delayed saccade trial and were directly followed by reinforcement. For three of the four SNr neuron classes, saccade-related modulations were only present before terminal saccades. For the fourth class, discrete pausers, saccade-related modulations were substantially larger for terminal saccades than for fixational saccades, and modulations were absent for spontaneous saccades. These results and other recent work on the basal ganglia suggest that some saccade-related signals in the SNr may be influenced by the reinforcement associated with a particular saccadic eye movement.
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Henik, Avishai, Robert Rafal i Dell Rhodes. "Endogenously Generated and Visually Guided Saccades after Lesions of the Human Frontal Eye Fields". Journal of Cognitive Neuroscience 6, nr 4 (lipiec 1994): 400–411. http://dx.doi.org/10.1162/jocn.1994.6.4.400.
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Nine patients with chronic, unilateral lesions of the dorso-lateral prefrontal cortex including the frontal eye fields (FEF) made saccades toward contralesional and ipsilesional fields. The saccades were either voluntarily directed in response to arrows in the center of a visual display, or were reflexively summoned by a peripheral visual signal. Saccade latencies were compared to those made by seven neurologic control patients with chronic, unilateral lesions of dorsolateral prefrontal cortex sparing the FEF, and by 13 normal control subjects. In both the normal and neurologic control subjects, reflexive saccades had shorter Latencies than voluntary saccades. In the FEF lesion patients, voluntary saccades had longer latencies toward the contralesional field than toward the ipsilesional field. The opposite pattern was found for reflexive saccades: latencies of saccades to targets in the contralesional field were shorter than saccades summoned to ipsilesional targets. Reflexive saccades toward the ipsilesional field had abnormally prolonged latencies; they were comparable to the latencies observed for voluntary Saccades. The effect of FEF lesions on saccacles contrasted with those observed in a second experiment requiring a key press response: FEF lesion patients were slower in making key press responses to signals detected in the contralesional field. To assess covert attention and preparatory set the effects of precues providing advance information were measured in both saccade and key press experiments. Neither patient group showed any deficiency in using precues to shift attention or to prepare saccades. The FEF facilitates the generation of voluntary saccatles and also inhibits reflexive saccades to exogenous signals. FEF lesions may disinhibit the ipsilesional midbrain which in turn may inhibit the opposite colliculus to slow reflexive saccades toward the ipsilesional field.
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Havermann, Katharina, Eckart Zimmermann i Markus Lappe. "Eye position effects in saccadic adaptation". Journal of Neurophysiology 106, nr 5 (listopad 2011): 2536–45. http://dx.doi.org/10.1152/jn.00023.2011.
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Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.
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Ohtsuka, K., i H. Noda. "Saccadic burst neurons in the oculomotor region of the fastigial nucleus of macaque monkeys". Journal of Neurophysiology 65, nr 6 (1.06.1991): 1422–34. http://dx.doi.org/10.1152/jn.1991.65.6.1422.
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1. The discharge of 255 neurons in the fastigial nuclei of three trained macaque monkeys was investigated during visually guided saccades. Responses of these neurons were examined also during horizontal head rotation and during microstimulation of the oculomotor vermis (lobules VIc and VII). 2. One hundred and two units were characterized by bursts of firing in response to visually guided saccades. Ninety-eight of these (96.1%) were located within the anatomic confines of the fastigial oculomotor region (FOR), on the basis of reconstruction of recording sites. During contralateral saccades, these neurons showed bursts that preceded the onset of saccades (presaccadic burst), whereas, during ipsilateral saccades, they showed bursts associated with the end of saccades (late saccadic burst). They were hence named saccadic burst neurons. Sixty-one saccadic burst neurons (62.2%) were inhibited during microstimulation of the oculomotor vermis with currents less than 10 microA. 3. All saccadic burst neurons were spontaneously active, and the resting firing rate varied considerably among units, ranging from 10 to 50 imp/s. The tonic levels of activity did not correlate significantly with eye position. 4. The presaccadic burst started 18.5 +/- 4.7 (SD) ms (n = 45) before the onset of saccades in the optimal direction (the direction associated with the maximum values of burst lead time, number of spikes per burst, and burst duration). Optimal directions covered the entire contralateral hemifield, although there was a slightly higher incidence in both horizontal and upper-oblique directions in the present sample. The duration of the presaccadic burst was highly correlated with the duration of saccade (0.85 less than or equal to r less than or equal to 0.97). 5. The late saccadic burst was most robust in the direction opposite to the optimal in each unit (the nonoptimal direction). Its onset preceded the completion of ipsilateral saccade by 30.4 +/- 5.9 ms. The lead time to the end of saccade was consistent among different units and was constant also for saccades of various sizes. Thus the late saccadic burst started even before the saccade onset when the saccade duration was less than 30 ms. Unlike the presaccadic burst, its duration was not related to the duration of saccade. 6. Discharge rates of saccadic burst neurons were correlated neither to eye positions during fixation nor to the initial eye positions before saccades. 7. Eye-position units and horizontal head-velocity units were located rostral to the FOR.(ABSTRACT TRUNCATED AT 400 WORDS)
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Ohtsuka, K., i H. Noda. "Discharge properties of Purkinje cells in the oculomotor vermis during visually guided saccades in the macaque monkey". Journal of Neurophysiology 74, nr 5 (1.11.1995): 1828–40. http://dx.doi.org/10.1152/jn.1995.74.5.1828.
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1. We previously described discharge properties of cerebellar output cells in the fastigial nucleus during ipsilateral and contralateral saccades. Fastigial cells exhibited unique responses depending on the direction of saccades and were involved in execution of accurate targeting saccades. Purkinje cells in the oculomotor vermis (lobules VIc and VII) are thought to modulate these discharges of fastigial cells. In this study we reexamine discharge properties of Purkinje cells on the basis of this hypothesis. 2. Initially we physiologically identified the right and left sides of the oculomotor vermis. Saccade-related discharges of 79 Purkinje cells were recorded from both sides of the vermis during visually guided saccades toward the sides ipsilateral and contralateral to the recording side in two trained macaque monkeys. To clarify the correlation of Purkinje cell discharge with burst activities in the fastigial nucleus during saccadic eye movements, we analyzed our data by employing methods used in the study of fastigial neurons. 3. Among the 79 cells, 56 (71%) showed burst discharges during saccades (saccadic burst cells). Of the 56 cells, 29 exhibited a peak of burst discharges in both the contralateral and ipsilateral directions (bidirectional cells). The remaining 27 saccadic burst cells showed a peak of burst discharges during either contralateral or ipsilateral saccades (unidirectional cells). Among the 79 cells, 14 (18%) exhibited a pause of discharges during contralateral saccades (pause cells). Among the 79 cells, 9 (11%) showed burst discharge during contralateral saccades followed by tonic discharge that was correlated with eye position (burst tonic cells). 4. The timing of bursts in bidirectional cells with respect to saccade onset was dependent on the direction of saccade. During ipsilateral saccades, Purkinje cells exhibited a long lead burst that built up gradually, peaked near the onset of the saccade, and terminated sharply near midsaccade. The mean lead time relative to saccade onset was 29.3 +/- 24.5 (SD) ms. During contralateral saccades, Purkinje cells exhibited a short lead/late burst that built up sharply, peaked near midsaccade, and terminated gradually after the end of the saccade. The mean lead time relative to saccade onset was 10.7 +/- 20.8 ms. The burst onset time during contralateral saccades and the burst offset time during ipsilateral saccades preceded the saccade offset time by about the same interval regardless of the saccade amplitude. 5. In pause cells the pause preceded saccade onset by 17.5 +/- 10.6 ms. The duration of the pause was not correlated with the duration of saccades. There was little trial-to-trial variability in the onset time of the pause with respect to the onset of saccades, whereas there was large trial-to-trial variability in the offset time of the pause with respect to the offset of saccades. In addition, the mean onset time of the pause for each cell had a relatively narrow distribution. 6. The burst lead time of burst tonic cells relative to saccade onset was 9.5 +/- 3.9 ms. The tonic discharge rate of burst tonic cells was a nonlinear function of eye position. The regression of each cell was fit to two lines. The regression coefficient ranged from 0.95 to 0.99 (mean = 0.97). 7. Axons of Purkinje cells in the oculomotor vermis are thought to project exclusively to saccadic burst cells in the fastigial oculomotor region (FOR), which is located in the caudal portion of the fastigial nucleus. Our previous studies indicated that FOR cells provide temporal signals for controlling targeting saccades. The present results suggest that Purkinje cells in the oculomotor vermis modify the temporal signals of FOR cells for saccades in different directions and amplitudes. The modification of FOR cell activity by Purkinje cells is thought to be essential for the function of the cerebellum in the control of saccadic eye movements.
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Crowder, Nathan A., Nicholas S. C. Price, Michael J. Mustari i Michael R. Ibbotson. "Direction and Contrast Tuning of Macaque MSTd Neurons During Saccades". Journal of Neurophysiology 101, nr 6 (czerwiec 2009): 3100–3107. http://dx.doi.org/10.1152/jn.91254.2008.
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Saccades are rapid eye movements that change the direction of gaze, although the full-field image motion associated with these movements is rarely perceived. The attenuation of visual perception during saccades is referred to as saccadic suppression. The mechanisms that produce saccadic suppression are not well understood. We recorded from neurons in the dorsal medial superior temporal area (MSTd) of alert macaque monkeys and compared the neural responses produced by the retinal slip associated with saccades (active motion) to responses evoked by identical motion presented during fixation (passive motion). We provide evidence for a neural correlate of saccadic suppression and expand on two contentious results from previous studies. First, we confirm the finding that some neurons in MSTd reverse their preferred direction during saccades. We quantify this effect by calculating changes in direction tuning index for a large cell population. Second, it has been noted that neural activity associated with saccades can arrive in the parietal cortex ≤30 ms earlier than activity produced by similar visual stimulation during fixation. This led to the question of whether the saccade-related responses were visual in origin or were motor signals arising from saccade-planning areas of the brain. By comparing the responses to saccades made over textured backgrounds of different contrasts, we provide strong evidence that saccade-related responses were visual in origin. Refinements of the possible models of saccadic suppression are discussed.
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Schnier, Fabian, i Markus Lappe. "Mislocalization of stationary and flashed bars after saccadic inward and outward adaptation of reactive saccades". Journal of Neurophysiology 107, nr 11 (1.06.2012): 3062–70. http://dx.doi.org/10.1152/jn.00877.2011.
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Recent studies have shown that saccadic inward adaptation (i.e., the shortening of saccade amplitude) and saccadic outward adaptation (i.e., the lengthening of saccade amplitude) rely on partially different neuronal mechanisms. There is increasing evidence that these differences are based on differences at the target registration or planning stages since outward but not inward adaptation transfers to hand-pointing and perceptual localization of flashed targets. Furthermore, the transfer of reactive saccade adaptation to long-duration overlap and scanning saccades is stronger after saccadic outward adaptation than that after saccadic inward adaptation, suggesting that modulated target registration stages during outward adaptation are increasingly used in the execution of saccades when the saccade target is visually available for a longer time. The difference in target presentation duration between reactive and scanning saccades is also linked to a difference in perceptual localization of different targets. Flashed targets are mislocalized after inward adaptation of reactive and scanning saccades but targets that are presented for a longer time (stationary targets) are mislocalized stronger after scanning than after reactive saccades. This link between perceptual localization and adaptation specificity suggests that mislocalization of stationary bars should be higher after outward than that after inward adaptation of reactive saccades. In the present study we test this prediction. We show that the relative amount of mislocalization of stationary versus flashed bars is higher after outward than that after inward adaptation of reactive saccades. Furthermore, during fixation stationary and flashed bars were mislocalized after outward but not after inward adaptation. Thus, our results give further evidence for different adaptation mechanisms between inward and outward adaptation and harmonize some recent research.
Rozprawy doktorskie na temat "Saccades"
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Vincent, Gautier. "Programmation des saccades oculaires". Paris, EHESS, 1999. http://www.theses.fr/1999EHESA010.
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Les informations visuelles portees par les mots peripheriques et utilisables pour la programmation des saccades oculaires lors de la lecture sont de deux types : de bas niveau (longueur, excentricite) ou de haut niveau (contenu linguistique : lexical, semantique. . . ). Les modeles de programmation des saccades oculaires se differencient en fonction de l'importance donnee aux informations visuelles de haut niveau nous pouvons distinguer deux types de modeles de programmation : les modeles pour lesquels l'analyse linguistique des mots peripheriques est suffisamment rapide pour influencer directement la programmation des saccades de progression, et les modeles pour lesquels l'analyse linguistique des mots peripheriques n'est pas suffisamment rapide. Nos conclusions determinent une position intermediaire et rejoignent celles proposees par le modele << strategie-tactiques >> (o'regan, 1990) : les processus de bas niveau fournissent tres rapidement des informations exploitables pour la programmation des saccades. Ces informations sont ensuite modulees au fur et a mesure que les processus d'analyse de haut niveau deviennent operationnels. A partir de nos analyses, nous avons defini un modelede programmation des saccades oculaires, base sur le centre de gravite pondere d'une carte topique d'activite cognitive. La ponderation est donnee par la valeur des points de la carte, et la position d'arrivee des saccades, par la localisation du centre de gravite pondere au sein de la carte. L'activite de cette carte represente l'integration progressive de l'activite cognitive globale associee au champ visuel peripherique. Cette activite est nulle au debut de la fixation, puis integre progressivement les informations de bas niveau puis de haut niveau, issues des mots peripheriques. Ce modele permet une reproduction precise de nos donnees (< 5% d'erreur), et complete le modele propose par findlay (1999).
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Lau, Li Wing. "Saccades to doubly-flashed targets". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34089.pdf.
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Diamond, Mark R. "The effect of saccades on visual sensitivity and time perception". University of Western Australia. School of Psychology, 2003. http://theses.library.uwa.edu.au/adt-WU2003.0038.
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Considerable evidence indicates that visual sensitivity is reduced during saccadic eye movement. A central question has been whether saccadic suppression results from a non-visual central signal, or whether the obligate image motion that accompanies saccades is itself sufficient to mask vision. In the first of a series of experiments described here, the visual and non-visual effects of saccades were distinguished by measuring contrast sensitivity to luminance modulated low spatial frequency gratings, at 17 cd·m¯² and 0.17 cd·m¯², in saccade conditions and in conditions in which saccade-like image motion was produced by the rotation of a mirror but when observers’ eyes were kept still. The time course of suppression was examined by making measurements from well before image motion began until well after it had ended. A tenfold decrease in contrast sensitivity was found for luminance-modulated gratings with saccades, but little suppression was found with simulated saccades. Adding high contrast noise to the visual display increased the magnitude and the duration of the suppression during simulated saccades but had little effect on suppression produced by real saccades. At lower luminance, suppression was found to be reduced, and its course shallower than at higher luminance. Simulated saccades produced shallower suppression over a longer time course at both higher and lower luminance. In a second experiment the time course of contrast sensitivity to chromatically modulated gratings, at 17 cd·m¯², was examined. No suppression was found; rather there was some evidence of an enhancement of sensitivity, both before and after saccades, relative to fixation conditions. Differences in the effects of real and simulated saccades in the magnitude and time course of sensitivity loss with luminance modulated gratings suggest that saccadic suppression has an extraretinal component that acts on the magnocellular system; the pattern of enhancement found in the later experiment suggests a selective favouring of the parvocellular system both immediately prior to and immediately after saccades. The possibility that the degree of enhancement in sensitivity varies across the visual field was examined using spatially localized stimuli (either high spatial frequency chromatically modulated gratings or letter combinations). Sensitivity was found to decrease at the initial fixation point during the 75 ms prior to saccadic onset and simultaneously to improve at the saccadic target. In the immediate post-saccadic period, sensitivity at the saccadic target was found to exceed that which had been manifest at the initial fixation point prior to saccades, suggesting that post-saccadic enhancement may improve the temporal contrast between one fixation and the next. The final experiments investigated the possibility that our sense of continuity across saccades (as opposed to stability) is influenced by saccade-induced errors in locating events in time. The results of these experiments suggest that saccades can result in errors in judging (a) the time at which external events occur relative to saccadic onset, (b) the temporal order of visual events, and (c) the magnitude of temporal intervals. It is concluded that apparent time is generally foreshortened prior to saccades. This might be due to selective suppression of magnocellular activity and might function to hide saccades and their effects from our awareness. A speculative synthesis is presented based on the idea that recurrent feedback between the neocortical and cortical structures on the one hand, and the thalamic nuclei on the other, has special importance for perception around the time of saccades
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Blum, Bernhard M. "Torsional control of eye-head saccades". Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-178260.
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Under natural conditions the head and the eye are both free to rotate about three mutuall orthogonal axes each (horizontal, vertical and torsional). Theoretically, these six degrees of freedom would allow any two-dimensional direction of the line of sight to be obtained by infinitely many torsional head and eye orientations. Yet, for any one gaze direction our brain chooses specific angles of torsion for the head and the eye. For steady fixation of distant targets with the head fixed and upright this observation is known as Donders' law (1847). It has been shown to hold independently of the direction of the rapid gaze shift (saccade) preceding a fixation. Surprisingly, despite considerable research on head and eye coordination the full implications of Donders' law still have not been analyzed for head-unrestrained gaze shifts. It has merely been studied whether torsional constraints hold, when gaze is returned repeatedly to the targets from single initial positions. The aim of this study was to see whether Donders' law holds after head-unrestrained saccades, independently of the saccade direction. Secondary objectives were to analyze whether the neural controls of the eye and the head are dependent or independent during this task and to collect and present control data for comparison with patient recordings in clinical context. Therefore, seven healthy human subjects made large head-unrestrained gaze shifts to a single set of visual targets during two separate conditions: 1) Repeated saccades to individual target positions from the same direction respectively (Star paradigm). 2) Repeated saccades to every target position from several different directions (Diamond paradigm). Three-dimensional orientations of head and eye were measured simultaneously with the magnetic search coil technique and consecutively plotted in three-dimensional space so that those orientations obeying Donders' law formed a surface. For each of the three body units the static orientations formed subspaces that resembled surfaces in the shape of twisted double saddles. Surfaces of head orientations had the most pronounced twist, eye in head surfaces were the most planar and surfaces of gaze orientations showed intermediate twist. The standard deviation of torsional residuals of the approximated surfaces (torsional thickness) was bigger for gaze than for the eye and smallest for the head.
Head and eye torsion, as averaged over individual fixations, were correlated differently within every subject, but between subjects there was no correlation. In summary, neither surface shapes nor torsional thickness of gaze, head or eye differed between the two conditions (Star/Diamond). With this it is shown for the first time that Donders' law of torsional control holds true for gaze, head and eye orientations independently of the direction of the preceding saccade. The absence of correlation between head and eye torsion can be explained by independent controllers of head and eye movements. This yields a new, further argument supporting recent models of neuronal gaze control that are based on the assumption of independent head and eye controllers. Studies with patients carrying lesions in possible target structures of such neuronal controllers are needed to further investigate these models. Finally, clinically-diagnostic relevance of this study arises from the comparison to results of studies on gaze coordination after midbrain lesions where patients exhibit an altered form of Donders' law.Unter natürlichen Bedingungen sind Rotationen von Kopf und Auge um jeweils drei voneinander unabhängige Raumachsen (Quer-, Hoch- und Längsachse) möglich. Diese sechs Freiheitsgrade würden beim Blick in jede zweidimensionale Richtung beliebige Drehungen um die Längsachse (Torsion) sowohl des Kopfes als auch des Auges erlauben. Unser Gehirn wählt jedoch in jeder Blickrichtung je einen spezifischen Torsionswinkel für Kopf und Auge. Für die Fixation entfernter Blickziele bei aufrechtem, unbewegtem Kopf wurde diese Tatsache als Donders' Law (1847) bekannt. Das Gesetz gilt unabhängig von der Richtung der der Fixation vorhergehenden raschen Blickbewegung (Sakkade). Überraschenderweise wurde trotz zahlreicher Untersuchungen zur Kopf- und Augenkoordination die vollständige Gültigkeit von Donders' Law bei Blickbewegungen mit bewegtem Kopf noch nicht gezeigt. Es wurde lediglich untersucht, ob die resultierenden Torsionsbeschränkungen weiter gelten, wenn der Blick wiederholt von denselben Ausgangspositionen auf verschiedene Punkte gerichtet wird. Hauptziel dieser Arbeit war zu prüfen, ob Donders' Law nach Sakkaden mit bewegtem Kopf unabhängig von der Sakkadenrichtung gilt. Zudem wurde analysiert, ob Kopf und Auge dabei einer gemeinsamen oder separaten neuronalen Kontrolle unterliegen, und es wurden Kontrolldaten zum Vergleich mit Patientenmessungen im klinischen Kontext gesammelt. Dazu führten sieben gesunde menschliche Probanden Sakkaden mit bewegtem Kopf zwischen einer Anordnung visueller Blickziele unter zwei Versuchsbedingungen durch: 1) Wiederholte Sakkaden auf jedes Ziel aus der jeweils gleichen Richtung (Star Paradigma). 2) Wiederholte Sakkaden auf jedes Ziel aus mehreren verschiedenen Richtungen (Diamond Paradigma). Die dreidimensionalen Kopf- und Augenbewegungen wurden simultan mit der magnetischen Search-Coil-Technik gemessen und zur Analyse räumlich dargestellt, so dass Positionen, die Donders' Law entsprechen, eine Fläche bilden. Für jede der drei Körpereinheiten lagen die statischen Positionen in Unterräumen, die Flächen in Form verdrehter (getwisteter) Doppelsättel ähnelten. Die Flächen der Kopfpositionen wiesen den deutlichsten Twist auf, die der Auge-im-Kopf Positionen waren nahezu eben und die Flächen der Blickpositionen zeigten einen mittleren Twist. Die Standardabweichung der Torsionsresiduen der genäherten Flächen (Torsionsdicke) war größer für den Blick als für das Auge und am kleinsten für den Kopf. Kopf- und Augentorsion, gemittelt über die Einzelfixationen, waren für jeden einzelnen Probanden unterschiedlich korreliert; über alle Probanden ergab sich jedoch keine signifikante Korrelation. Zusammenfassend unterschieden sich weder Flächenform noch Torsionsdicke von Blick, Kopf oder Auge zwischen den beiden Bedingungen (Star/ Diamond). Damit ist zum ersten Mal gezeigt, dass Donders' Law für Blick-, Kopf- und Augenpositionen unabhängig von der Richtung der vorangegangenen Sakkade gilt. Die fehlende Korrelation der Kopf- und Augentorsion ist auf eine unabhängige Kontrolle von Kopf- und Augenbewegungen zurückzuführen. Dies ist ein neues, weiteres Argument zur Bestätigung aktueller Modelle der neuronalen Kontrolle von Blickbewegungen, die von der Annahme unabhängiger Kopf- und Augencontroller ausgehen. Studien mit Patienten, die Läsionen in möglichen Zielstrukturen für solche neuronalen Controller tragen, sind zur weiteren Untersuchung dieser Modelle nötig. Abschließend ergibt sich klinisch-diagnostische Relevanz der Arbeit aus dem Vergleich mit Studiendaten zur Blickkoordination nach Mittelhirnläsionen, bei denen Patienten eine veränderte Form von Donders' Law aufweisen.
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Gaymard, Bertrand. "Controle cerebral de l'amplitude des saccades". Paris 6, 1995. http://www.theses.fr/1995PA066604.
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Les etapes cerebrales de l'elaboration du signal qui specifie l'amplitude d'une saccade sont passees en revue, ainsi que les travaux que nous avons realise et s'y rapportant. La premiere etape comprend des mecanismes de perception et d'attention visuelles. La deuxieme etape est sensori-motrice et a lieu dans les aires oculomotrices corticales. C'est la qu'ont lieu les changements de coordonnees qui assurent un codage precis de la saccade. Nous avons demontre (etudes 1 et 2) que l'aire oculomotrice frontale (fef) code la position d'une cible dans un systeme de coordonnees retiniennes, alors que l'aire oculomotrice supplementaire et le cortex vestibulaire utilisent un systeme de coordonnees spatiales. Nous avons demontre (etudes 3 et 4) que le fef est implique dans le controle des saccades volontaires, predites ou memorisees. La troisieme etape est la transmission du signal moteur au colliculus et au cervelet. Nous avons demontre que le signal visuel (etude 5) est utilise pour ajuster la precision de la saccade. La quatrieme etape est la transmission du signal moteur aux structures premotrices. Nous avons demontre (etude 6) que la proprioception oculaire intervient dans le maintien de la conjugaison oculaire. La cinquieme etape declenche une eventuelle saccade de correction. Elle utilise pour cela la decharge corollaire, dont la precision met en jeu des mecanismes de calibrage. Nous avons demontre (etude 6) que le thalamus joue un role essentiel dans ces mecanismes. Nous avons etudie la contribution du fef et du cervelet au systeme de detection d'erreur
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Ohl, Sven. "Small eye movements during fixation : the case of postsaccadic fixation and preparatory influences". Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2014/6986/.
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Describing human eye movement behavior as an alternating sequence of saccades and fixations turns out to be an oversimplification because the eyes continue to move during fixation. Small-amplitude saccades (e.g., microsaccades) are typically observed 1-2 times per second during fixation.
Research on microsaccades came in two waves. Early studies on microsaccades were dominated by the question whether microsaccades affect visual perception, and by studies on the role of microsaccades in the process of fixation control. The lack of evidence for a unique role of microsaccades led to a very critical view on the importance of microsaccades.
Over the last years, microsaccades moved into focus again, revealing many interactions with perception, oculomotor control and cognition, as well as intriguing new insights into the neurophysiological implementation of microsaccades.
In contrast to early studies on microsaccades, recent findings on microsaccades were accompanied by the development of models of microsaccade generation. While the exact generating mechanisms vary between the models, they still share the assumption that microsaccades are generated in a topographically organized saccade motor map that includes a representation for small-amplitude saccades in the center of the map (with its neurophysiological implementation in the rostral pole of the superior colliculus).
In the present thesis I criticize that models of microsaccade generation are exclusively based on results obtained during prolonged presaccadic fixation. I argue that microsaccades should also be studied in a more natural situation, namely the fixation following large saccadic eye movements. Studying postsaccadic fixation offers a new window to falsify models that aim to account for the generation of small eye movements. I demonstrate that error signals (visual and extra-retinal), as well as non-error signals like target eccentricity influence the characteristics of small-amplitude eye movements.
These findings require a modification of a model introduced by Rolfs, Kliegl and Engbert (2008) in order to account for the generation of small-amplitude saccades during postsaccadic fixation. Moreover, I present a promising type of survival analysis that allowed me to examine time-dependent influences on postsaccadic eye movements. In addition, I examined the interplay of postsaccadic eye movements and postsaccadic location judgments, highlighting the need to include postsaccadic eye movements as covariate in the analyses of location judgments in the presented paradigm.
In a second goal, I tested model predictions concerning preparatory influences on microsaccade generation during presaccadic fixation. The observation, that the preparatory set significantly influenced microsaccade rate, supports the critical model assumption that increased fixation-related activity results in a larger number of microsaccades.
In the present thesis I present important influences on the generation of small-amplitude saccades during fixation. These eye movements constitute a rich oculomotor behavior which still poses many research questions. Certainly, small-amplitude saccades represent an interesting source of information and will continue to influence future studies on perception and cognition.Die Beschreibung des Blickbewegungsverhaltens als eine sich abwechselnde Folge von Sakkaden und Fixationen stellt eine starke Vereinfachung dar, denn auch während einer Fixation bewegen sich die Augen. Typischerweise treten Bewegungen von kleiner Amplitude (z.B. Mikrosakkaden), 1-2 mal pro Sekunde während einer Fixation auf. Frühe Studien zu Mikrosakkaden wurden von Fragen bezüglich des Einflusses von Mikrosakkaden auf die visuelle Wahrnehmung, und Studien zu der Rolle von Mikrosakkaden bei der Fixationskontrolle dominiert. Fehlende Evidenz für eine Rolle, die ausschließlich Mikrosakkaden zufällt, führten zu einer sehr kritischen Betrachtung von Mikrosakkaden. In den letzten Jahren rückten Mikrosakkaden wieder mehr in den Fokus. Vielerlei Zusammenhänge mit Wahrnehmung, okulomotorischer Kontrolle und Kognition, sowie neue Erkenntnisse bezüglich der neurophysiologischen Implementierung von Mikrosakkaden konnten aufgedeckt werden. In den letzten Jahren wurden verschiedene Modelle der Mikrosakkadengenerierung vorgestellt. Auch wenn sich diese in ihren exakten Mechanismen unterscheiden, so teilen sie doch die Annahme, dass Mikrosakkaden in einer topographisch organisierten motorischen Karte für Sakkaden ausgelöst werden. Diese Karten beinhalten eine Repräsentation für klein-amplitudige Sakkaden im Zentrum der Karte (mit dem rostralen Pol der colliculi superiores als neurophysiologische Implementierung). In der vorliegenden Arbeit kritisiere ich, dass Modelle der Mikrosakkadengenerierung ausschließlich auf Resultaten langanhaltender präsakkadischer Fixation beruhen. Ich führe an, dass Mikrosakkaden in einer natürlicheren Situation untersucht werden sollten, nämlich während der Fixation nach einer großen Sakkade. Die Untersuchung postsakkadischer Fixation bietet eine neue Möglichkeit Modelle der Mikrosakkadengenerierung zu falsifizieren. In den Studien zeige ich, dass Signale über den Fehler in der Sakkadenlandeposition (visuelle und extra-retinale), sowie fehler-unabhängige Signale, wie die Zielreiz-Exzentrizität, einen entscheidenden Einfluss auf kleine Sakkaden haben. Diese Resultate erfordern Modifikationen an dem kürzlich eingeführten Modell von Rolfs, Kliegl und Engbert (2008), um die Generierung von kleinen Sakkaden auch während der postsakkadischen Fixation erklären zu können. Darüber hinaus präsentiere ich eine viel versprechende Ereigniszeitanalyse, die uns erlaubt zeitabhängige Einflüsse auf das postsakkadische Blickbewegungsverhalten zu untersuchen. Außerdem untersuche ich das Zusammenspiel von postsakkadischen Augenbewegungen und postsakkadischen Positionsurteilen. Dabei wird die Bedeutung von postsakkadischen Augenbewegungen als Kovariate in den statistischen Analysen betont. Ein zweites Ziel dieser Arbeit besteht darin Modellvorhersagen bezüglich vorbereitender Einflüsse auf die Mikrosakkadengenerierung zu untersuchen. Die Ergebnisse, hinsichtlich eines signifikanten Einflusses des preparatory set auf die Mikrosakkadenrate unterstützt die wesentliche Modellannahme, dass erhöhte fixationsbezogene Aktivität zu einer größeren Anzahl an Mikrosakkaden führt. In der vorliegenden Arbeit präsentiere ich wichtige Einflüsse auf die Generierung von kleinen Sakkaden während der Fixation. Diese Augenbewegungen stellen ein vielseitiges okulomorisches Verhalten dar, welche weiterhin zahlreiche Fragen mit sich bringen und sicherlich zukünftige Studien zu Wahrnehmung und Kognition beeinflussen werden.
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Laidlaw, Kaitlin Elizabeth Wiggins. "Greater distractor interference during vertical saccades : the time course of horizontal, vertical, and oblique saccadic curvature". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27270.
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In three studies, we characterize the effect of a nearby distractor on vertical, horizontal and oblique saccadic curvature under normal saccade preparation times. In Experiments 1 and 2, participants made saccades to targets in the presence or absence of a nearby distractor. Consistent with previous findings, longer-latency vertical saccades showed greater curvature away from a distractor than did oblique or horizontal saccades. At short latencies, vertical saccades showed greater curvature towards the distractor. We propose that vertical saccades may be prone to greater distractor interference due to the superior colliculus, a midbrain region implicated in attentional and saccadic shifts, under-representing vertical target objects, which results in a relative over-representation of non-vertical distractor objects. In Experiment 3, we tested this hypothesis by having participants make saccades to vertical or horizontal targets in the presence or absence of bright or dim distractors. We reasoned that weaker representations for vertical targets would allow for greater interference from nearby distractors, which would be especially pronounced when distractors are highly salient. Consistent with this prediction, we found that only the trajectory of vertical saccades was modulated by distractor luminance.
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Savina, Olga. "Effects of training to an area-cue on human saccadic eye movements". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100209.
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Several recent studies have investigated advanced preparation of oculomotor programs after training to make saccades to a specific location in space. However, in natural visual scenes, we seldom know the precise stimulus location, rather, we often know the general area where target of interest may appear. Here, we investigated how human saccadic reaction time (SRT) and saccade final landing position may be affected by training to attend to an area where a target will appear. Additionally, we looked at how training to an area of one size may influence eye movements to targets presented in a larger area. Subjects were trained to attend to an area-cue of 6° in diameter, always presented in the same quadrant of the visual field, at the same spatial coordinates. During training, targets were presented at random locations inside the cued area. After training, targets were presented inside an area-cue (except for a few catch trials) of either the same size or of a larger size (i.e. 10° diameter). Results show that training-related saccades were directed toward individually distinctive preferred regions inside the trained area, and towards identical regions in relative coordinates inside the larger 10° area. Importantly, training-related saccades were mostly in the anticipatory range, a large proportion of which was followed by the corrective second saccades directed towards the target. Our findings suggest that anticipatory saccades should be considered in the assessment of training-related changes in oculomotor preparation of saccadic programming.
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Jones, Garrett L. "Noisy optimal control strategies for modelling saccades". Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39845.
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Eye movements have for a while provided us a closer view into how the brain commands the body. Particularly interesting are saccades: fast and accurate eye movements that allow us to scan our visual surroundings. One observation is that motor commands issued by the brain are corrupted by a signal-dependent noise. Moreover, the variance of the signal scales linearly with the control signal squared. It is assumed that such uncertainty in the dynamics introduces a probability distribution of the eye that the brain accounts for during motion planning.
We propose a framework for computing the optimal control law for arbitrary dynamical systems, subject to noise, and where the cost function depends on a statistical distribution of the eye’s position. A key contribution of this framework is estimating the endpoint distribution of the plant using Monte Carlo sampling, which is done efficiently using commodity graphics hardware in parallel. We then describe a modified form of gradient descent for computing the optimal control law for an objective function prone to stochastic effects. We compare our approach to other methods, such as downhill simplex and Covariance-Matrix-Adaptation, which are considered “gradient-free” approaches to optimization. We finally conclude with several examples that show the framework successfully controlling saccades for different plant models of the oculomotor system: this includes a 3D torque-based model of the eye, and a a nonlinear model of the muscle actuator that drives the eye.
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Griffiths, Helen Jane. "Saccades in the absence of binocular vision". Thesis, University of Sheffield, 2003. http://etheses.whiterose.ac.uk/3031/.
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The mechanism of suppression in strabismus is unclear and contribution of the suppressing eye to the generation of eye movements has received little attention. A series of nine experiments tested how the strabismic eye contributes to saccade generation in the presence of suppression and also considered the effect of the strabismic eye in the presence of abnormal retinal correspondence (ARC). These data were compared with data from subjects with normal binocular single vision (BSV). Chapters 2 and 3 describe the equipment, laboratory set-up and testing of the equipment used in the thesis for measuring eye movements, Skalar IRIS 6500 infrared limbal tracker, and presenting stimuli to each eye separately. The design of a novel method for dissociation of the eyes using four liquid crystal polymer shutters is presented. Chapter 4 compares the characteristics of saccades made by subjects with normal BSV (n=5) and strabismus (n=8). The effect of distractors on saccades is explored in Chapter 5 in subjects with normal BSV (n=5). The experiment documents the distractor effect produced in the described laboratory set-up, and compares it with that previously reported by Walker et al (1997). This is investigated further by comparing the effect of distractor presentations to the dominant eye, non-dominant eye or both eyes. There was no difference in the effect on saccade latency or gain with distractors presented to the dominant or non-dominant eye. The effect of binocular distractors on saccade gain was greater than monocular presentations. Chapter 6 repeats the experiment of Chapter 5 in subjects with constant strabismus and suppression (n=6) and constant strabismus with ARC (n=2) and found that distractors in the strabismic eye did affect saccades however the response differed from normal BSV. This was true even though it was shown that the distractor was not perceived by the strabismic eye. Chapter 7 investigates the influence of the central fixation target in the strabismic eye on saccade generation by inducing disconjugate saccade adaptation in subjects with normal BSV (n=8) and constant strabismus and suppression (n=6). The findings were that in the presence of suppression, disconjugate adaptation similar to that in normal BSV was possible. The conclusion of this thesis is to suggest that information from the suppressed eye is available to the saccadic system by either a sub-cortical pathway or processed cortically without conscious awareness.
Książki na temat "Saccades"
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Poissant, Maude. Saccades: Nouvelles. Québec, [Québec]: Hamac, 2014.
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Lau, Li Wing. Saccades to doubly-flashed targets. Ottawa: National Library of Canada, 1998.
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Eizenman, Moshe. Continuity and asymmetry in amplitude-duration relations for normal eye saccades. Toronto: Dept. of Computer Science, University of Toronto, 1986.
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A, Stern John, i United States. Office of Aviation Medicine., red. Blinks, saccades, and fixation pauses during vigilance task performance.: Final report. Washington, D.C: U.S. Dept. of Transportation, Federal Aviation Administration, Office of Aviation Medicine, 1996.
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A, Stern John, i United States. Office of Aviation Medicine., red. Blinks, saccades, and fixation pauses during vigilance task performance.: Final report. Washington, D.C: U.S. Dept. of Transportation, Federal Aviation Administration, Office of Aviation Medicine, 1994.
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d', Ydewalle Géry, Rensbergen Johan van i European Conference on Eye Movements (6th : 1991 : University of Leuven), red. Visual and oculomotor functions: Advances in eye movement research. Amsterdam: North-Holland, 1994.
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dʼ, Ydewalle Géry, i Rensbergen Johan van, red. Perception and cognition: Advances in eye movement research. Amsterdam: North-Holland, 1993.
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Lelorain, Patrice. Saccages. Monaco: Rocher, 2002.
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Saccages. Montréal, Québec: La Courte échelle, 2013.
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-Ing, Becker Wolfgang Dr, Deubel Heiner i European Conference on Eye Movements (9th : 1997 : Ulm, Germany), red. Current oculomotor research: Physiological and psychological aspects. New York: Plenum Press, 1999.
Znajdź pełny tekst źródłaCzęści książek na temat "Saccades"
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Jensen, Kelsey, i Aasef Shaikh. "Slow Saccades". W Advances in Translational Neuroscience of Eye Movement Disorders, 203–19. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31407-1_11.
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Starzyk, Janusz A. "Visual Saccades for Object Recognition". W Artificial Intelligence and Soft Computing, 778–88. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19324-3_70.
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Girard, Benoît. "Basal Ganglia: Control of Saccades". W Encyclopedia of Computational Neuroscience, 330–32. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4614-6675-8_516.
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Pierce, Jordan E., Brett A. Clementz i Jennifer E. McDowell. "Saccades: Fundamentals and Neural Mechanisms". W Eye Movement Research, 11–71. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20085-5_2.
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Rucker, Janet C., Todd Hudson i John Ross Rizzo. "Translational Neurology of Slow Saccades". W Advances in Translational Neuroscience of Eye Movement Disorders, 221–54. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31407-1_12.
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Girard, Benoît. "Basal Ganglia: Control of Saccades". W Encyclopedia of Computational Neuroscience, 1–4. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4614-7320-6_516-1.
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Girard, Benoît. "Basal Ganglia: Control of Saccades". W Encyclopedia of Computational Neuroscience, 1–3. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4614-7320-6_516-2.
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Müri, R. M., A. C. Nirkko, C. Ozdoba, P. Tobler, O. Heid, G. Schroth i C. W. Hess. "Functional MRI of Double Step Saccades". W Current Oculomotor Research, 235–39. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4757-3054-8_33.
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Fischer, Burkhart. "The preparation of visually guided saccades". W Reviews of Physiology, Biochemistry and Pharmacology, 1–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/bfb0027574.
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Sereno, Anne B. "Programming Saccades: The Role of Attention". W Springer Series in Neuropsychology, 89–107. New York, NY: Springer New York, 1992. http://dx.doi.org/10.1007/978-1-4612-2852-3_6.
Pełny tekst źródłaStreszczenia konferencji na temat "Saccades"
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Sato, Masayuki, i Keiji Uchikawa. "Spectral Sensitivity by Increment Threshold during Saccades". W Advances in Color Vision. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/acv.1992.fb18.
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Images on the retina change rapidly during saccades. The visual system integrates clear images before and after saccades to produce a stable perception of the outside scene. It is said that during saccades the visual system is suppressed to eliminates the smeared images, which may disturb integration of the retinal images.1) It has not been well understood how the visual system eliminate the smeared images. Luminance and chromatic channels in the visual system seem to play different roles to perceive the outside scene.2) If the saccadic suppression is useful to integrate images, luminance and chromatic channels may be suppressed differently during saccades. In this report, we measured spectral sensitivity functions by the increment threshold method during saccades and fixation in order to clarify the effects of saccadic suppression on luminance and chromatic channels.3),4)
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Elsner, Ann E., C. Wall i J. Johnson. "Aging in visual-vestibular interactions". W OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.wf4.
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To search rapidly for information in a scene, it is critical to make quick, accurate saccadic eye movements. Often, while making these movements, a body or head movement is required. Thus, vestibular and saccadic eye movements must be coordinated. It is known that the vestibular system can change with age; e.g., the gain of the system can decrease with age, particularly at low frequencies. However, the effects on saccadic eye movements are not understood. Using a pseudorandom vestibular stimulus (rotation about the vertical) with frequencies from 0.02 to 1.67 Hz, we have measured (a) the gain and phase of the vestibulo-ocular reflex and (b) saccade parameters. Saccade targets were three red LEDs, positioned in the center and 9° to either side. We recruited five observers, 62–69 years, who had been normal on a battery of vestibular tests 2 years prior. There was a slight loss of low frequency relative to high frequency gain, but this trend was not significant. However, the average number of saccade errors doubled while rotating vs remaining stationary. Most errors during rotation were (a) single or multistep saccades of less than half-amplitude or (b) slow eye movements.
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Shioiri, Satoshi, i Patrick Cavanagh. "Saccadic suppression of energy-based motion". W OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.thk5.
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Previous studies have shown that small displacements that are easily detected in normal viewing become invisible if they occur during a saccade. However, it is not clear what process is suppressed during a saccade; energy-based (short-range) motion, form-based (long-range) motion, and perception of position change can all contribute to the displacement detection. We measured motion detection during a saccade using a random-dot stimulus presented within a stationary frame. This stimulus has no identifiable form whose displacement can be noticed either directly or by activation of the form-based motion process. Therefore, the impression of motion produced by the displacement of this stimulus must be mediated by the energy-based motion process alone. Saccadic suppression was found for the stimuli when they were displaced a small distance (less than Dmax) either in spatial coordinates or in retinal coordinates. This result implies that the energy-based motion process is suppressed during the saccade, and since this process is able to signal motion for stimuli with ISIs longer than the duration of saccades in our experiment (mean of 60 ms), it appears to be suppressed across the saccade as well.
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Thibodeaux, David, Hassan Muhammad, Silvana L. Costa i Tara L. Alvarez. "Instrumentation to stimulate gap saccades, pro-saccades, and overlap saccades". W 2014 40th Annual Northeast Bioengineering Conference (NEBEC). IEEE, 2014. http://dx.doi.org/10.1109/nebec.2014.6972957.
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Zelinsky, Greg J., i Heinrich H. Bülthoff. "Hypothesis testing in the planning of saccadic eye movements". W OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.mqq10.
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Recent computer models of active vision adopt the broad categories of stimulus-driven and concept-driven eye movements to control the saccade-like movements of their cameras. Although low-level target selection may be accomplished by assigning priorities to areas on a saliency map, the question of how high-level feedback might influence saccadic movements is open to debate. One widely recognized solution to this problem defines this top-down input in terms of a hypothesistesting strategy. According to this model, foveal information and peripheral information are combined to suggest various hypothetical descriptions of a scene. Saccadic movements would then be used to confirm or reject the most likely of these hypotheses. An experiment was conducted to determine under what conditions a hypothesis-testing scheme is used and at what stage such information becomes available to the human occulomotor system. Subjects were asked to discriminate among four similar patterns while their eye movements were recorded by a two-dimensional binocular eye-tracker. The initial saccade made to each pattern was then used to determine if and when targets providing disambiguating information were preferred over targets providing only redundant information. This paradigm permits a systematic study of these top-down influences on the planning of saccades and may have implications for models of active vision.
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Zhai, Xiu, Alireza Ghahari i John D. Enderle. "Parameter Estimation of Auditory Saccades and Visual Saccades". W 2013 39th Annual Northeast Bioengineering Conference (NEBEC). IEEE, 2013. http://dx.doi.org/10.1109/nebec.2013.123.
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Ishida, Taiichiro, Hiroyuki Shinoda i Mitsuo Ikeda. "Threshold displacement size for perceiving a stable stimulus across saccades: effects of equiluminance". W Advances in Color Vision. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/acv.1992.sab3.
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We perceive the external world as stable despite saccadic eye movements. How this is achieved has been one of the important problems in the field of vision research. In recent years, several studies have shown that the subject can perceive a stable stimulus even if the stimulus is displaced a certain amount during saccades.1-4) In our previous study, 2) we found that tolerable displacement size for perceiving a stable stimulus was influenced by properties of a stimulus. The subject tended to detect movements in the parts of a picture that appeared conspicuous. On the other hand, the subject was not able to notice movements in rather homogeneous parts of the picture. It remains to be elucidated what features of a picture have an effect on integrating visual information across saccades.
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Rolff, Tim, Frank Steinicke i Simone Frintrop. "When do Saccades begin? Prediction of Saccades as a Time-to-Event Problem". W ETRA '22: 2022 Symposium on Eye Tracking Research and Applications. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3517031.3529627.
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He, Peiyuan. "How do saccades aid visual pattern recognition?" W OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.tuy15.
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It has been shown that saccades play an important role in visual tasks, but they do not simply improve resolution of the display. To understand their role, I studied not only the way in which texture perception benefits from saccades, but also the patterns of saccades that are most beneficial. The displays (55) consisted of 1515 randomly oriented T's and L's. The T's formed a random polygonal shape (target) in the central 24 of the display. Eye movements were recorded while subjects estimated both the size and the shape of the target and were under instructions to (1) SCAN the display with saccades or (2) maintain the line of sight in the center without saccades (STAY). The results are as follows: (1) SCAN performance improved with increasing display duration; (2) STAY performance did not improve with increasing display duration longer than 2 s; (3) scanning improved performance for 5 s durations; (4) scanning improved the ability to detect texture patterns; (5) retinal image transients, created by flickering (2 Hz) or jumping (0.5 Hz, 15 ft. [4.57 m] peak-to-peak amplitude) the display, improved performance somewhat for size discrimination but not for shape discrimination; (6) boundary scanning was more beneficial for discrimination than other scanning patterns.
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Johnson, J. D., i T. A. Grogan. "Neural Network Controlled Visual Saccades". W OE/LASE '89, redaktorzy Eamon B. Barrett i James J. Pearson. SPIE, 1989. http://dx.doi.org/10.1117/12.952677.
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Capo-Aponte, Jose E. Pupillometry and Saccades as Objective mTBI Biomark. Fort Belvoir, VA: Defense Technical Information Center, październik 2015. http://dx.doi.org/10.21236/ada624533.
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Baker, Laura, Robert Goldstein i John A. Stern. Saccadic Eye Movements in Deception. Fort Belvoir, VA: Defense Technical Information Center, grudzień 1992. http://dx.doi.org/10.21236/ada304658.
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Kennedy, Robert S., James G. May, Marshall B. Jones i Jennifer E. Fowlkes. Development of Saccade Length Index of Taskload for Biocybernetic Application. Fort Belvoir, VA: Defense Technical Information Center, styczeń 1989. http://dx.doi.org/10.21236/ada205199.
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May, James G., Robert S. Kennedy i Jennifer E. Fowlkes. Development of Saccade Length Index of Taskload for Biocybernetic Application. Fort Belvoir, VA: Defense Technical Information Center, listopad 1987. http://dx.doi.org/10.21236/ada189384.
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Saccade dysmetria indicates attenuated visual exploration in autism spectrum disorder. ACAMH, lipiec 2020. http://dx.doi.org/10.13056/acamh.12454.
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