• To our knowledge, there has not been a large-N examination of the temporal properties of saccades and fixations in scenes. (frontiersin.org)
  • As a consequence, the properties of saccades and smooth pursuit were studied independently. (eneuro.org)
  • Head-fixed saccades can have amplitudes of up to 90° (from one edge of the oculomotor range to the other), but in normal conditions saccades are far smaller, and any shift of gaze larger than about 20° is accompanied by a head movement. (wikipedia.org)
  • Typical saccade amplitudes and fixation durations have been described by relatively small-N studies and reviews over the years. (frontiersin.org)
  • Here, we show that the magnitude of perceptual compression for a wide variety of probe stimuli and saccade amplitudes is quantitatively predicted by a simple heuristic model based on the geometry of retinotopic representations in the primate brain. (jneurosci.org)
  • Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for fixation, rapid eye movement, and the fast phase of optokinetic nystagmus. (wikipedia.org)
  • For visually guided saccades, neurons in the superior colliculus (SC) emit a burst of spikes to register the appearance of stimulus, and many of the same neurons discharge another burst to initiate the eye movement. (bvsalud.org)
  • In anticipation of each saccade, many neurons in the visual system shift their receptive fields. (duke.edu)
  • Saccades can be categorized by intended goal in four ways: In a visually guided saccade, the eyes move toward a visual transient, or stimulus. (wikipedia.org)
  • We therefore compared amplitude levels and onset times of both spike bursts and LFP modulations recorded simultaneously with a laminar probe along the dorsoventral axis of SC in 3 male monkeys performing the visually guided delayed saccade task. (bvsalud.org)
  • For humans, visual tracking of moving stimuli often triggers catch-up saccades during smooth pursuit. (eneuro.org)
  • The results suggest an increase in latency and reaction time to detect complex stimuli, e.g. the recognition of emotional facial expressions. (bvsalud.org)
  • Saccades may rotate the eyes in any direction to relocate gaze direction (the direction of sight that corresponds to the fovea), but normally saccades do not rotate the eyes torsionally. (wikipedia.org)
  • During such gaze saccades, first, the eye produces a saccade to get gaze on target, whereas the head follows more slowly and the vestibulo-ocular reflex (VOR) causes the eyes to roll back in the head to keep gaze on the target. (wikipedia.org)
  • Possible PSP requires the presence of a gradually progressive disorder with onset at age 40 or later, either vertical supranuclear gaze palsy or both slowing of vertical saccades and prominent postural instability with falls in the first year of onset, as well as no evidence of other diseases that could explain these features. (neurology.org)
  • The switch between these continuous and discrete eye movements is a trade-off between tolerating sustained position error (PE) when no saccade is triggered or a transient loss of vision during the saccade due to saccadic suppression. (eneuro.org)
  • Informed by model predictions, we hypothesized that saccade trigger time length and variability will increase when pre-saccadic predicted errors are small or visual uncertainty is high (e.g., for blurred targets). (eneuro.org)
  • Spiking activity along the dorsoventral axis was recorded with a laminar probe as Rhesus monkeys generated saccades to the same stimulus location in tasks that require either executive control to delay saccade onset until permission is granted or the production of an immediate response to a target whose onset is predictable. (bvsalud.org)
  • A saccade (/səˈkɑːd/ sə-KAHD, French for jerk) is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction. (wikipedia.org)
  • We report baseline measures of eye movement behavior in our sample, including mean fixation duration, saccade amplitude, and initial saccade latency. (frontiersin.org)
  • The duration of each fixation and the amplitude of the saccades between them vary with the contents of the current scene, the viewer's task, and unique aspects of the individual viewer. (frontiersin.org)
  • General estimates of saccade amplitude and fixation durations are valuable to our understanding of how we process scenes. (frontiersin.org)
  • However, both saccade amplitude and fixation duration are influenced by a variety of factors. (frontiersin.org)
  • Saccades to an unexpected stimulus normally take about 200 milliseconds (ms) to initiate, and then last from about 20-200 ms, depending on their amplitude (20-30 ms is typical in language reading). (wikipedia.org)
  • The amplitude of a saccade is the angular distance the eye travels during the movement. (wikipedia.org)
  • From these studies, it is thought that saccades in scenes tend to be 2-4° in amplitude ( Henderson and Hollingworth, 1998 ) and fixations tend to last 200-300 ms ( Rayner, 2009 ). (frontiersin.org)
  • Under this assumption, the psychophysical data on perisaccadic compression can be appreciated intuitively by imagining that, around the time of a saccade, the brain confounds nearby oculomotor and sensory signals while attempting to localize the position of objects in visual space. (jneurosci.org)
  • To produce goal-directed eye movements known as saccades, we must channel sensory input from our environment through a process known as sensorimotor transformation. (bvsalud.org)
  • Consequently, our current understanding describes saccades and pursuit as two outcomes of a synergistic sensorimotor process, sharing sensory inputs, anatomic pathways, and functional regulation ( Orban de Xivry and Lefèvre, 2007 ). (eneuro.org)
  • High CISS scores were correlated with variability and increased latency. (arvojournals.org)
  • Saccades are one of the fastest movements produced by the human eye (blinks may reach even higher peak velocities). (wikipedia.org)
  • The high peak velocities and the main sequence relationship can also be used to distinguish micro-/saccades from other eye movements (like ocular tremor, ocular drift, and smooth pursuit). (wikipedia.org)
  • Thus, accurate tracking requires a synergistic coordination of saccades and smooth pursuit eye movements to overcome retinal position and velocity mismatches, respectively. (eneuro.org)
  • Specific pre-target oscillatory (alpha rhythms) and transient activities occurring in posterior-lateral parietal cortex and occipital cortex also characterise express saccades. (wikipedia.org)
  • Velocity-based algorithms are a common approach for saccade detection in eye tracking. (wikipedia.org)
  • In summary, our data supports our hypothesized predicted error-based decision process for coordinating saccades during smooth pursuit. (eneuro.org)
  • The mechanism by which the brain decides when to trigger discrete catch-up saccades during continuous smooth pursuit has eluded researchers for decades. (eneuro.org)
  • Our results add support for a common and shared sensorimotor process for saccades and pursuit. (eneuro.org)
  • For a long time, it was believed that saccades and smooth pursuit were controlled by independent functional and anatomic systems in the brain ( Robinson, 1986 ). (eneuro.org)
  • Using electrical stimulation to evoke saccades from the dorsomedial frontal cortex (DMFC) and frontal eye fields (FEF) of rhesus monkeys, parametric tests were conducted to compare the excitability properties of these regions. (duke.edu)
  • Specifically, we propose that perisaccadic compression is determined by the distance between the probe and saccade end point on a map that has a logarithmic representation of visual space, similar to those found in numerous cortical and subcortical visual structures. (jneurosci.org)
  • These saccades are generated by a neuronal mechanism that bypasses time-consuming circuits and activates the eye muscles more directly. (wikipedia.org)
  • demonstrated that catch-up saccades were less likely to occur when the target re-crosses the fovea within 40-180 ms. To date, there is no mechanistic explanation for how the trigger decision is made by the brain. (eneuro.org)
  • When significant position error (PE) is accumulated, a catch-up saccade may be triggered to re-foveate the target. (eneuro.org)
  • Likewise, saccades and their properties were thought to be strictly governed by position inputs ( Wurtz and Optican, 1994 ). (eneuro.org)
  • in our data, this resulted in longer saccade trigger times and more smooth trials without saccades. (eneuro.org)