@article{ThielRomanoKurthsetal.2008, author = {Thiel, Marco and Romano, Maria Carmen and Kurths, J{\"u}rgen and Rolfs, Martin and Kliegl, Reinhold}, title = {Generating surrogates from recurrences}, issn = {1364-503X}, year = {2008}, abstract = {In this paper, we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i.e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be only one centre in the brain that produces the fixational movements in both eyes or a close link between the two centres.}, language = {en} } @article{ThielRomanoKurthsetal.2006, author = {Thiel, Marco and Romano, Maria Carmen and Kurths, J{\"u}rgen and Rolfs, Martin and Kliegl, Reinhold}, title = {Twin surrogates to test for complex synchronisation}, doi = {10.1209/epl/i2006-10147-0}, year = {2006}, abstract = {We present an approach to generate (multivariate) twin surrogates (TS) based on recurrence properties. This technique generates surrogates which correspond to an independent copy of the underlying system, i.e. they induce a trajectory of the underlying system starting at different initial conditions. We show that these surrogates are well suited to test for complex synchronisation and exemplify this for the paradigmatic system of Rossler oscillators. The proposed test enables to assess the statistical relevance of a synchronisation analysis from passive experiments which are typical in natural systems}, language = {en} } @article{RomanoThielKurthsetal.2006, author = {Romano, Maria Carmen and Thiel, Marco and Kurths, J{\"u}rgen and Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold}, title = {Synchronization Analysis and Recurrence in Complex Systems}, isbn = {978-3-527-40623-4}, year = {2006}, language = {en} } @article{RolfsOhl2011, author = {Rolfs, Martin and Ohl, Sven}, title = {Visual suppression in the superior colliculus around the time of microsaccades}, series = {Journal of neurophysiology}, volume = {105}, journal = {Journal of neurophysiology}, number = {1}, publisher = {American Chemical Society}, address = {Bethesda}, issn = {0022-3077}, doi = {10.1152/jn.00862.2010}, pages = {1 -- 3}, year = {2011}, abstract = {Miniature eye movements jitter the retinal image unceasingly, raising the question of how perceptual continuity is achieved during visual fixation. Recent work discovered suppression of visual bursts in the superior colliculus around the time of microsaccades, tiny jerks of the eyes that support visual perception while gaze is fixed. This finding suggests that corollary discharge, supporting visual stability when rapid eye movements drastically shift the retinal image, may also exist for the smallest saccades.}, language = {en} } @article{RolfsLaubrockKliegl2006, author = {Rolfs, Martin and Laubrock, Jochen and Kliegl, Reinhold}, title = {Shortening and prolongation of saccade latencies following microsaccades}, doi = {10.1007/s00221-005-0148-1}, year = {2006}, abstract = {When the eyes fixate at a point in a visual scene, small saccades rapidly shift the image on the retina. The effect of these microsaccades on the latency of subsequent large-scale saccades may be twofold. First, microsaccades are associated with an enhancement of visual perception. Their occurrence during saccade target perception could, thus, decrease saccade latencies. Second, microsaccades are likely to indicate activity in fixation-related oculomotor neurons. These represent competitors to saccade-related cells in the interplay of gaze holding and shifting. Consequently, an increase in saccade latencies would be expected after microsaccades. Here, we present evidence for both aspects of microsaccadic impact on saccade latency. In a delayed response task, participants made saccades to visible or memorized targets. First, microsaccade occurrence up to 50 ms before target disappearance correlated with 18 ms (or 8\%) faster saccades to memorized targets. Second, if microsaccades occurred shortly (i.e., < 150 ms) before a saccade was required, mean saccadic reaction time in visual and memory trials was increased by about 40 ms (or 16\%). Hence, microsaccades can have opposite consequences for saccade latencies, pointing at a differential role of these fixational eye movements in the preparation of saccade motor programs}, language = {en} } @article{RolfsLaubrockKliegl2008, author = {Rolfs, Martin and Laubrock, Jochen and Kliegl, Reinhold}, title = {Microsaccade-induced prolongation of saccadic latencies depends on microsaccade amplitude}, issn = {1995-8692}, year = {2008}, language = {en} } @article{RolfsKlieglEngbert2008, author = {Rolfs, Martin and Kliegl, Reinhold and Engbert, Ralf}, title = {Toward a model of microsaccade generation : the case of microsaccadic inhibition}, issn = {1534-7362}, doi = {10.1167/8.11.5}, year = {2008}, language = {en} } @article{RolfsEngbertKliegl2005, author = {Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold}, title = {Crossmodal coupling of oculomotor control and spatial attention in vision and audition}, issn = {0014-4819}, year = {2005}, abstract = {Fixational eye movements occur involuntarily during visual fixation of stationary scenes. The fastest components of these miniature eye movements are microsaccades, which can be observed about once per second. Recent studies demonstrated that microsaccades are linked to covert shifts of visual attention. Here, we generalized this finding in two ways. First, we used peripheral cues, rather than the centrally presented cues of earlier studies. Second, we spatially cued attention in vision and audition to visual and auditory targets. An analysis of microsaccade responses revealed an equivalent impact of visual and auditory cues on microsaccade-rate signature (i.e. an initial inhibition followed by an overshoot and a final return to the pre-cue baseline rate). With visual cues or visual targets, microsaccades were briefly aligned with cue direction and then opposite to cue direction during the overshoot epoch, probably as a result of an inhibition of an automatic saccade to the peripheral cue. With left auditory cues and auditory targets microsaccades oriented in cue direction. We argue that microsaccades can be used to study crossmodal integration of sensory information and to map the time course of saccade preparation during covert shifts of visual and auditory attention}, language = {en} } @article{RolfsEngbertKliegl2004, author = {Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold}, title = {Microsaccade orientation supports attentional enhancement opposite to a peripheral cue}, year = {2004}, language = {en} } @article{RolfsDambacherCavanagh2013, author = {Rolfs, Martin and Dambacher, Michael and Cavanagh, Patrick}, title = {Visual adaptation of the perception of causality}, series = {Current biology}, volume = {23}, journal = {Current biology}, number = {3}, publisher = {Cell Press}, address = {Cambridge}, issn = {0960-9822}, doi = {10.1016/j.cub.2012.12.017}, pages = {250 -- 254}, year = {2013}, abstract = {We easily recover the causal properties of visual events, enabling us to understand and predict changes in the physical world. We see a tennis racket hitting a ball and sense that it caused the ball to fly over the net; we may also have an eerie but equally compelling experience of causality if the streetlights turn on just as we slam our car's door. Both perceptual [1] and cognitive [2] processes have been proposed to explain these spontaneous inferences, but without decisive evidence one way or the other, the question remains wide open [3-8]. Here, we address this long-standing debate using visual adaptation-a powerful tool to uncover neural populations that specialize in the analysis of specific visual features [9-12]. After prolonged viewing of causal collision events called "launches" [1], subsequently viewed events were judged more often as noncausal. These negative aftereffects of exposure to collisions are spatially localized in retinotopic coordinates, the reference frame shared by the retina and visual cortex. They are not explained by adaptation to other stimulus features and reveal visual routines in retinotopic cortex that detect and adapt to cause and effect in simple collision stimuli.}, language = {en} }