Journal articles: 'Saccadic Reaction Times'

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Dorris, M. C., and D. P. Munoz. "A neural correlate for the gap effect on saccadic reaction times in monkey." Journal of Neurophysiology 73, no. 6 (June 1, 1995): 2558–62. http://dx.doi.org/10.1152/jn.1995.73.6.2558.

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1. The reduction in saccadic reaction time associated with the introduction of a period of darkness between the disappearance of an initial fixation point and the appearance of a new peripheral saccade target is known as the gap effect. Fixation cells in the rostral pole of the monkey superior colliculus have been implicated in the control of active visual fixation and suppressing saccadic eye movements. To determine whether specific variations of fixation cell discharge was correlated to the gap effect, we recorded the activity of fixation cells while a monkey generated visually guided saccades with various temporal gaps between the disappearance of the initial fixation point and the appearance of a peripheral saccade target. 2. The saccadic reaction times of the monkey were shortest with gap durations of 200-300 ms and increased with shorter or longer gap durations. The activity of fixation cells followed a similar time course, having a minimum discharge rate 200-300 ms into the gap, and increased activity at the time of target appearance with smaller or larger gap durations. 3. We propose that the activity of fixation cells in the monkey superior colliculus provide a neural correlate of the gap effect. The decrease in activity of fixation cells 200-300 ms into the gap weakens the powerful state of inhibition which they normally exert upon the saccade generating system, allowing targets to be acquired at shorter reaction times.

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Thura, David, Driss Boussaoud, and Martine Meunier. "Hand Position Affects Saccadic Reaction Times in Monkeys and Humans." Journal of Neurophysiology 99, no. 5 (May 2008): 2194–202. http://dx.doi.org/10.1152/jn.01271.2007.

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In daily life, activities requiring the hand and eye to work separately are as frequent as activities requiring tight eye–hand coordination, and we effortlessly switch from one type of activity to the other. Such flexibility is unlikely to be achieved without each effector “knowing” where the other one is at all times, even when it is static. Here, we provide behavioral evidence that the mere position of the static hand affects one eye movement parameter: saccadic reaction time. Two monkeys were trained and 11 humans instructed to perform nondelayed or delayed visually guided saccades to either a right or a left target while holding their hand at a location either near or far from the eye target. From trial to trial, target locations and hand positions varied pseudorandomly. Subjects were tested both when they could and when they could not see their hand. The main findings are 1) the presence of the static hand in the workspace did affect saccade initiation; 2) this interaction persisted when the hand was invisible; 3) it was strongly influenced by the delay duration: hand–target proximity retarded immediate saccades, whereas it could hasten delayed saccades; and 4) this held true both for humans and for each of the two monkeys. We propose that both visual and nonvisual hand position signals are used by the primates' oculomotor system for the planning and execution of saccades, and that this may result in a hand–eye competition for spatial attentional resources that explains the delay-dependent reversal observed.

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Dorris, Michael C., Tracy L. Taylor, Raymond M. Klein, and Douglas P. Munoz. "Influence of Previous Visual Stimulus or Saccade on Saccadic Reaction Times in Monkey." Journal of Neurophysiology 81, no. 5 (May 1, 1999): 2429–36. http://dx.doi.org/10.1152/jn.1999.81.5.2429.

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Influence of previous visual stimulus or saccade on saccadic reaction times in monkey. Saccadic reaction times (SRTs) to suddenly appearing targets are influenced by neural processes that occur before and after target presentation. The majority of previous studies have focused on how posttarget factors, such as target attributes or changes in task complexity, affect SRTs. Studies of pretarget factors have focused on how prior knowledge of the timing or location of the impending target, gathered through cueing or probabilistic information, affects SRTs. Our goal was to investigate additional pretarget factors to determine whether SRTs can also be influenced by the history of saccadic and visual activity even when these factors are spatially unpredictive as to the location of impending saccadic targets. Monkeys were trained on two paradigms. In the saccade-saccadeparadigm, monkeys were required to follow a saccadic target that stepped from a central location, to an eccentric location, back to center, and finally to a second eccentric location. The stimulus-saccade paradigm was similar, except the central fixation target remained illuminated during presentation of the first eccentric stimulus; the monkey was required to maintain central fixation and to make a saccade to the second eccentric stimulus only on disappearance of the fixation point. In both paradigms, the first eccentric stimulus was presented at the same, opposite, or orthogonal location with respect to the final target location in a given trial. We measured SRTs to the final target under conditions in which all parameters were identical except for the location of the first eccentric stimulus. In the saccade-saccade paradigm, we found that the SRT to the final target was slowest when it was presented opposite to the initial saccadic target, whereas in the stimulus-saccade paradigm the SRT to the final target was slowest when it was presented at the same location as the initial stimulus. In both paradigms, these increases in SRTs were greatest during the shortest intervals between presentation of successive eccentric stimuli, yet these effects remained present for the longest intervals employed in this study. SRTs became faster as the direction and eccentricity of the two successive stimuli became increasingly misaligned from that which produced the maximal SRT slowing in each paradigm. The results of the stimulus-saccade paradigm are similar to the phenomenon of inhibition of return (IOR) in which human subjects are slower to respond to stimuli that are presented at previously cued locations. We interpret these findings in terms of overlapping representations of visuospatial and oculomotor activity in the same neural structures.

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Shinomiya, Yuma, Tetsuto Yamada, Kenji Suzuki, Yuko Komachi, and Takahiro Niida. "Saccadic Reaction Times in Alternating Cover." Strabismus 21, no. 2 (May 29, 2013): 74–77. http://dx.doi.org/10.3109/09273972.2013.786744.

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Steinmetz, Nicholas A., and Tirin Moore. "Changes in the Response Rate and Response Variability of Area V4 Neurons During the Preparation of Saccadic Eye Movements." Journal of Neurophysiology 103, no. 3 (March 2010): 1171–78. http://dx.doi.org/10.1152/jn.00689.2009.

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The visually driven responses of macaque area V4 neurons are modulated during the preparation of saccadic eye movements, but the relationship between presaccadic modulation in area V4 and saccade preparation is poorly understood. Recent neurophysiological studies suggest that the variability across trials of spiking responses provides a more reliable signature of motor preparation than mean firing rate across trials. We compared the dynamics of the response rate and the variability in the rate across trials for area V4 neurons during the preparation of visually guided saccades. As in previous reports, we found that the mean firing rate of V4 neurons was enhanced when saccades were prepared to stimuli within a neuron's receptive field (RF) in comparison with saccades to a non-RF location. Further, we found robust decreases in response variability prior to saccades and found that these decreases predicted saccadic reaction times for saccades both to RF and non-RF stimuli. Importantly, response variability predicted reaction time whether or not there were any accompanying changes in mean firing rate. In addition to predicting saccade direction, the mean firing rate could also predict reaction time, but only for saccades directed to the RF stimuli. These results demonstrate that response variability of area V4 neurons, like mean response rate, provides a signature of saccade preparation. However, the two signatures reflect complementary aspects of that preparation.

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Stevenson, Scott A., James K. Elsley, and Brian D. Corneil. "A “Gap Effect” on Stop Signal Reaction Times in a Human Saccadic Countermanding Task." Journal of Neurophysiology 101, no. 2 (February 2009): 580–90. http://dx.doi.org/10.1152/jn.90891.2008.

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The “gap effect” describes a phenomenon whereby saccadic reaction times are expedited by the removal of a visible fixation point prior to target presentation. Here we investigated whether processes controlling saccade cancellation are also subjected to a gap effect. Human subjects performed a countermanding experiment that required them to try to cancel an impending saccade in the presence of an imperative visual stop signal, across different fixation conditions. We found that saccadic cancellation latencies, estimated via derivation of the stop signal reaction time (SSRT), were ∼40 ms shorter on trials with a 200-ms gap between fixation point removal and target presentation compared with when the fixation point remained illuminated. Follow-up experiments confirmed that the reduction in SSRTs were primarily due to removal of a foveal fixation point (as opposed to a generalized warning effect) and persisted with an auditory stop signal that controlled for potential differences in stop signal saliency across different fixation conditions. Saccadic RTs exhibited a gap effect in all experiments with reductions in RTs being due to both removal of a foveal fixation point and a generalized warning effect. Overall, our results demonstrate that processes controlling saccade cancellation can be expedited by a 200-ms gap. The simultaneous priming of both saccade cancellation and generation is of particular interest considering the mutually antagonistic relationship between the saccade fixation and generation networks in the oculomotor system.

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Whitchurch, Elizabeth A., and Terry T. Takahashi. "Combined Auditory and Visual Stimuli Facilitate Head Saccades in the Barn Owl (Tyto alba)." Journal of Neurophysiology 96, no. 2 (August 2006): 730–45. http://dx.doi.org/10.1152/jn.00072.2006.

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The barn owl naturally responds to an auditory or visual stimulus in its environment with a quick head turn toward the source. We measured these head saccades evoked by auditory, visual, and simultaneous, co-localized audiovisual stimuli to quantify multisensory interactions in the barn owl. Stimulus levels ranged from near to well above saccadic threshold. In accordance with previous human psychophysical findings, the owl's saccade reaction times (SRTs) and errors to unisensory stimuli were inversely related to stimulus strength. Auditory saccades characteristically had shorter reaction times but were less accurate than visual saccades. Audiovisual trials, over a large range of tested stimulus combinations, had auditory-like SRTs and visual-like errors, suggesting that barn owls are able to use both auditory and visual cues to produce saccades with the shortest possible SRT and greatest accuracy. These results support a model of sensory integration in which the faster modality initiates the saccade and the slower modality remains available to refine saccade trajectory.

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Reingold, Eyal M., and Dave M. Stampe. "Saccadic Inhibition in Voluntary and Reflexive Saccades." Journal of Cognitive Neuroscience 14, no. 3 (April 1, 2002): 371–88. http://dx.doi.org/10.1162/089892902317361903.

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The present study investigated saccadic inhibition in both voluntary and stimulus-elicited saccades. Two experiments examined saccadic inhibition caused by an irrelevant flash occurring subsequent to target onset. In each trial, participants were required to perform a single saccade following the presentation of a black target on a gray background, 4° to the left or to the right of screen center. In some trials (flash trials), after a variable delay, a 33-msec flash was displayed at the top and bottom third of the monitor (these regions turned white). In all experimental conditions, histograms of flash-to-saccade latencies documented a decrease in saccadic frequency, forming a dip, time-locked to the flash and occurring as early as 60—70 msec following its onset. The fast latency of this effect strongly suggests a low-level, reflex-like, oculomotor effect, which was referred to as saccadic inhibition. A novel procedure was developed to allow comparisons of saccadic inhibition even across conditions, which in the absence of a flash (no-flash trials) produce dissimilar saccadic reaction times (SRTs) distributions. Experiment 1 examined the effects of the fixation stimulus on saccadic inhibition by contrasting three conditions: a gap condition (fixation stimulus disappeared 200 msec prior to target onset), a step condition (offset of the fixation stimulus was simultaneous with target onset), and an overlap condition (the fixation stimulus remained on for the duration of the trial). The overlap condition produced substantially stronger saccadic inhibition, relative to the gap and the step conditions. Experiment 2 contrasted the saccadic inhibition effect obtained for prosaccades (saccades aimed at the target) with the effect obtained for antisaccades (i.e., saccades aimed away from the same target). The onset of saccadic inhibition was earlier, and its magnitude was stronger, for antisaccades, relative to prosaccades. The plausibility that the superior colliculus is the neurophysiological locus of the saccadic inhibition effect was explored.

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Reuter, Eva-Maria, Welber Marinovic, Timothy N. Welsh, and Timothy J. Carroll. "Increased preparation time reduces, but does not abolish, action history bias of saccadic eye movements." Journal of Neurophysiology 121, no. 4 (April 1, 2019): 1478–90. http://dx.doi.org/10.1152/jn.00512.2018.

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The characteristics of movements are strongly history-dependent. Marinovic et al. (Marinovic W, Poh E, de Rugy A, Carroll TJ. eLife 6: e26713, 2017) showed that past experience influences the execution of limb movements through a combination of temporally stable processes that are strictly use dependent and dynamically evolving and context-dependent processes that reflect prediction of future actions. Here we tested the basis of history-dependent biases for multiple spatiotemporal features of saccadic eye movements under two preparation time conditions (long and short). Twenty people performed saccades to visual targets. To prompt context-specific expectations of most likely target locations, 1 of 12 potential target locations was specified on ~85% of the trials and each remaining target was presented on ~1% trials. In long preparation trials participants were shown the location of the next target 1 s before its presentation onset, whereas in short preparation trials each target was first specified as the cue to move. Saccade reaction times and direction were biased by recent saccade history but according to distinct spatial tuning profiles. Biases were purely expectation related for saccadic reaction times, which increased linearly as the distance from the repeated target location increased when preparation time was short but were similar to all targets when preparation time was long. By contrast, the directions of saccades were biased toward the repeated target in both preparation time conditions, although to a lesser extent when the target location was precued (long preparation). The results suggest that saccade history affects saccade dynamics via both use- and expectation-dependent mechanisms and that movement history has dissociable effects on reaction time and saccadic direction. NEW & NOTEWORTHY The characteristics of our movements are influenced not only by concurrent sensory inputs but also by how we have moved in the past. For limb movements, history effects involve both use-dependent processes due strictly to movement repetition and processes that reflect prediction of future actions. Here we show that saccade history also affects saccade dynamics via use- and expectation-dependent mechanisms but that movement history has dissociable effects on saccade reaction time and direction.

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Castaldi, Elisa, David Burr, Marco Turi, and Paola Binda. "Fast saccadic eye-movements in humans suggest that numerosity perception is automatic and direct." Proceedings of the Royal Society B: Biological Sciences 287, no. 1935 (September 23, 2020): 20201884. http://dx.doi.org/10.1098/rspb.2020.1884.

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Fast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discriminate numerosities with high accuracy and great speed, as fast as 190 ms. Intermediate numerosities were more likely to elicit fast saccades than very low or very high numerosities. Reaction-times for vocal responses (collected in a separate experiment) were slower, did not depend on numerical range, and correlated only with the slow not the fast saccades, pointing to different systems. The short saccadic reaction-times we observe are surprising given that discrimination using numerosity estimation is thought to require a relatively complex neural circuit, with several relays of information through the parietal and prefrontal cortex. Our results suggest that fast numerosity-driven saccades may be generated on a single feed-forward pass of information recruiting a primitive system that cuts through the cortical hierarchy and rapidly transforms the numerosity information into a saccade command.

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Gregory, Nicola J., and Timothy L. Hodgson. "Giving Subjects the Eye and Showing Them the Finger: Socio-Biological Cues and Saccade Generation in the Anti-Saccade Task." Perception 41, no. 2 (January 1, 2012): 131–47. http://dx.doi.org/10.1068/p7085.

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Pointing with the eyes or the finger occurs frequently in social interaction to indicate direction of attention and one's intentions. Research with a voluntary saccade task (where saccade direction is instructed by the colour of a fixation point) suggested that gaze cues automatically activate the oculomotor system, but non-biological cues, like arrows, do not. However, other work has failed to support the claim that gaze cues are special. In the current research we introduced biological and non-biological cues into the anti-saccade task, using a range of stimulus onset asynchronies (SOAs). The anti-saccade task recruits both top–down and bottom–up attentional mechanisms, as occurs in naturalistic saccadic behaviour. In experiment 1 gaze, but not arrows, facilitated saccadic reaction times (SRTs) in the opposite direction to the cues over all SOAs, whereas in experiment 2 directional word cues had no effect on saccades. In experiment 3 finger pointing cues caused reduced SRTs in the opposite direction to the cues at short SOAs. These findings suggest that biological cues automatically recruit the oculomotor system whereas non-biological cues do not. Furthermore, the anti-saccade task set appears to facilitate saccadic responses in the opposite direction to the cues.

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Munoz, Douglas P., Irene T. Armstrong, Karen A. Hampton, and Kimberly D. Moore. "Altered Control of Visual Fixation and Saccadic Eye Movements in Attention-Deficit Hyperactivity Disorder." Journal of Neurophysiology 90, no. 1 (July 2003): 503–14. http://dx.doi.org/10.1152/jn.00192.2003.

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Attention-deficit hyperactivity disorder (ADHD) is characterized by the overt symptoms of impulsiveness, hyperactivity, and inattention. A frontostriatal pathophysiology has been hypothesized to produce these symptoms and lead to reduced ability to inhibit unnecessary or inappropriate behavioral responses. Oculomotor tasks can be designed to probe the ability of subjects to generate or inhibit reflexive and voluntary responses. Because regions of the frontal cortex and basal ganglia have been identified in the control of voluntary responses and saccadic suppression, we hypothesized that children and adults diagnosed with ADHD may have specific difficulties in oculomotor tasks requiring the suppression of reflexive or unwanted saccadic eye movements. To test this hypothesis, we measured eye movement performance in pro- and anti-saccade tasks of 114 ADHD and 180 control participants ranging in age from 6 to 59 yr. In the pro-saccade task, participants were instructed to look from a central fixation point toward an eccentric visual target. In the anti-saccade task, stimulus presentation was identical, but participants were instructed to suppress the saccade to the stimulus and instead look from the central fixation point to the side opposite the target. The state of fixation was manipulated by presenting the target either when the central fixation point was illuminated (overlap condition) or at some time after it disappeared (gap condition). In the pro-saccade task, ADHD participants had longer reaction times, greater intra-subject variance, and their saccades had reduced peak velocities and increased durations. In the anti-saccade task, ADHD participants had greater difficulty suppressing reflexive pro-saccades toward the eccentric target, increased reaction times for correct anti-saccades, and greater intra-subject variance. In a third task requiring prolonged fixation, ADHD participants generated more intrusive saccades during periods when they were required to maintain steady fixation. The results suggest that ADHD participants have reduced ability to suppress unwanted saccades and control their fixation behavior voluntarily, a finding that is consistent with a fronto-striatal pathophysiology. The findings are discussed in the context of recent neurophysiological data from nonhuman primates that have identified important control signals for saccade suppression that emanate from frontostriatal circuits.

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Sendhilnathan, Naveen, Debaleena Basu, and Aditya Murthy. "Simultaneous analysis of the LFP and spiking activity reveals essential components of a visuomotor transformation in the frontal eye field." Proceedings of the National Academy of Sciences 114, no. 24 (June 1, 2017): 6370–75. http://dx.doi.org/10.1073/pnas.1703809114.

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The frontal eye field (FEF) is a key brain region to study visuomotor transformations because the primary input to FEF is visual in nature, whereas its output reflects the planning of behaviorally relevant saccadic eye movements. In this study, we used a memory-guided saccade task to temporally dissociate the visual epoch from the saccadic epoch through a delay epoch, and used the local field potential (LFP) along with simultaneously recorded spike data to study the visuomotor transformation process. We showed that visual latency of the LFP preceded spiking activity in the visual epoch, whereas spiking activity preceded LFP activity in the saccade epoch. We also found a spatially tuned elevation in gamma band activity (30–70 Hz), but not in the corresponding spiking activity, only during the delay epoch, whose activity predicted saccade reaction times and the cells’ saccade tuning. In contrast, beta band activity (13–30 Hz) showed a nonspatially selective suppression during the saccade epoch. Taken together, these results suggest that motor plans leading to saccades may be generated internally within the FEF from local activity represented by gamma activity.

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Mackert, A., and M. Flechtner. "Saccadic reaction times in acute and remitted schizophrenics." European Archives of Psychiatry and Neurological Sciences 239, no. 1 (January 1989): 33–38. http://dx.doi.org/10.1007/bf01739741.

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Neggers, S. F. W., and H. Bekkering. "Ocular Gaze is Anchored to the Target of an Ongoing Pointing Movement." Journal of Neurophysiology 83, no. 2 (February 1, 2000): 639–51. http://dx.doi.org/10.1152/jn.2000.83.2.639.

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It is well known that, typically, saccadic eye movements precede goal-directed hand movements to a visual target stimulus. Also pointing in general is more accurate when the pointing target is gazed at. In this study, it is hypothesized that saccades are not only preceding pointing but that gaze also is stabilized during pointing in humans. Subjects, whose eye and pointing movements were recorded, had to make a hand movement and a saccade to a first target. At arm movement peak velocity, when the eyes are usually already fixating the first target, a new target appeared, and subjects had to make a saccade toward it ( dynamical trial type). In the statical trial type, a new target was offered when pointing was just completed. In a control experiment, a sequence of two saccades had to be made, with two different interstimulus intervals (ISI), comparable with the ISIs found in the first experiment for dynamic and static trial types. In a third experiment, ocular fixation position and pointing target were dissociated, subjects pointed at not fixated targets. The results showed that latencies of saccades toward the second target were on average 155 ms longer in the dynamic trial types, compared with the static trial types. Saccades evoked during pointing appeared to be delayed with approximately the remaining deceleration time of the pointing movement, resulting in “normal” residual saccadic reaction times (RTs), measured from pointing movement offset to saccade movement onset. In the control experiment, the latency of the second saccade was on average only 29 ms larger when the two targets appeared with a short ISI compared with trials with long ISIs. Therefore the saccadic refractory period cannot be responsible for the substantially bigger delays that were found in the first experiment. The observed saccadic delay during pointing is modulated by the distance between ocular fixation position and pointing target. The largest delays were found when the targets coincided, the smallest delays when they were dissociated. In sum, our results provide evidence for an active saccadic inhibition process, presumably to keep steady ocular fixation at a pointing target and its surroundings. Possible neurophysiological substrates that might underlie the reported phenomena are discussed.

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Krebs, Ruth M., C. Nicolas Boehler, Helen H. Zhang, Mircea A. Schoenfeld, and Marty G. Woldorff. "Electrophysiological recordings in humans reveal reduced location-specific attentional-shift activity prior to recentering saccades." Journal of Neurophysiology 107, no. 5 (March 1, 2012): 1393–402. http://dx.doi.org/10.1152/jn.00912.2010.

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Being able to effectively explore the visual world is of fundamental importance, and it has been suggested that the straight-ahead gaze position within the egocentric reference frame (“primary position”) might play a special role in this context. In the present study we employed human electroencephalography (EEG) to examine neural activity related to the spatial guidance of saccadic eye movements. Moreover, we sought to investigate whether such activity would be modulated by the spatial relation of saccade direction to the primary gaze position (recentering saccades). Participants executed endogenously cued saccades between five equidistant locations along the horizontal meridian. This design allowed for the comparison of isoamplitude saccades from the same starting position that were oriented either toward the primary position (centripetal) or further away from it (centrifugal). By back-averaging time-locked to the saccade onset on each trial, we identified a parietally distributed, negative-polarity EEG deflection contralateral to the direction of the upcoming saccade. Importantly, this contralateral presaccadic negativity, which appeared to reflect the location-specific attentional guidance of the eye movement, was attenuated for recentering saccades relative to isoamplitude centrifugal saccades. This differential electrophysiological signature was paralleled by faster saccadic reaction times and was substantially more apparent when time-locking the data to the onset of the saccade rather than to the onset of the cue, suggesting a tight temporal association with saccade initiation. The diminished level of this presaccadic component for recentering saccades may reflect the preferential coding of the straight-ahead gaze position, in which both the eye-centered and head-centered reference frames are perfectly aligned and from which the visual world can be effectively explored.

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Smyrnis, Nikolaos, Thomas Karantinos, Ioannis Malogiannis, Christos Theleritis, Asimakis Mantas, Nicholas C. Stefanis, John Hatzimanolis, and Ioannis Evdokimidis. "Larger variability of saccadic reaction times in schizophrenia patients." Psychiatry Research 168, no. 2 (July 2009): 129–36. http://dx.doi.org/10.1016/j.psychres.2008.04.015.

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Gezeck, Stefan, Burkhart Fischer, and Jens Timmer. "Saccadic reaction times: a statistical analysis of multimodal distributions." Vision Research 37, no. 15 (August 1997): 2119–31. http://dx.doi.org/10.1016/s0042-6989(97)00022-9.

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Baker, T., and S. Adler. "Saccadic reaction times and speed of information processing development." Journal of Vision 8, no. 6 (April 8, 2010): 916. http://dx.doi.org/10.1167/8.6.916.

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Braun, D., and B. G. Breitmeyer. "Relationship between directed visual attention and saccadic reaction times." Experimental Brain Research 73, no. 3 (December 1988): 546–52. http://dx.doi.org/10.1007/bf00406613.

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Hafed, Ziad M., and Laurent Goffart. "Gaze direction as equilibrium: more evidence from spatial and temporal aspects of small-saccade triggering in the rhesus macaque monkey." Journal of Neurophysiology 123, no. 1 (January 1, 2020): 308–22. http://dx.doi.org/10.1152/jn.00588.2019.

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Rigorous behavioral studies made in human subjects have shown that small-eccentricity target displacements are associated with increased saccadic reaction times, but the reasons for this remain unclear. Before characterizing the neurophysiological foundations underlying this relationship between the spatial and temporal aspects of saccades, we tested the triggering of small saccades in the male rhesus macaque monkey. We also compared our results to those obtained in human subjects, both from the existing literature and through our own additional measurements. Using a variety of behavioral tasks exercising visual and nonvisual guidance of small saccades, we found that small saccades consistently require more time than larger saccades to be triggered in the nonhuman primate, even in the absence of any visual guidance and when valid advance information about the saccade landing position is available. We also found a strong asymmetry in the reaction times of small upper versus lower visual field visually guided saccades, a phenomenon that has not been described before for small saccades, even in humans. Following the suggestion that an eye movement is not initiated as long as the visuo-oculomotor system is within a state of balance, in which opposing commands counterbalance each other, we propose that the longer reaction times are a signature of enhanced times needed to create the symmetry-breaking condition that puts downstream premotor neurons into a push-pull regime necessary for rotating the eyeballs. Our results provide an important catalog of nonhuman primate oculomotor capabilities on the miniature scale, allowing concrete predictions on underlying neurophysiological mechanisms. NEW & NOTEWORTHY Leveraging a multitude of neurophysiological investigations in the rhesus macaque monkey, we generated and tested hypotheses about small-saccade latencies in this animal model. We found that small saccades always take longer, on average, than larger saccades to trigger, regardless of visual and cognitive context. Moreover, small downward saccades have the longest latencies overall. Our results provide an important documentation of oculomotor capabilities of an indispensable animal model for neuroscientific research in vision, cognition, and action.

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Colonius, Hans, and Adele Diederich. "Multisensory Interaction in Saccadic Reaction Time: A Time-Window-of-Integration Model." Journal of Cognitive Neuroscience 16, no. 6 (July 2004): 1000–1009. http://dx.doi.org/10.1162/0898929041502733.

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Saccadic reaction time to visual targets tends to be faster when stimuli from another modality (in particular, audition and touch) are presented in close temporal or spatial proximity even when subjects are instructed to ignore the accessory input (focused attention task). Multisensory interaction effects measured in neural structures involved in saccade generation (in particular, the superior colliculus) have demonstrated a similar spatio-temporal dependence. Neural network models of multisensory spatial integration have been shown to generate convergence of the visual, auditory, and tactile reference frames and the sensorimotor coordinate transformations necessary for coordinated head and eye movements. However, because these models do not capture the temporal coincidences critical for multisensory integration to occur, they cannot easily predict multisensory effects observed in behavioral data such as saccadic reaction times. This article proposes a quantitative stochastic framework, the time-window-of-integration model, to account for the temporal rules of multisensory integration. Saccadic responses collected from a visual–tactile focused attention task are shown to be consistent with the time-window-of-integration model predictions.

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Weber, Heike. "Presaccadic Processes in the Generation of Pro and anti Saccades in Human Subjects—A Reaction-Time Study." Perception 24, no. 11 (November 1995): 1265–80. http://dx.doi.org/10.1068/p241265.

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It has been widely acknowledged that the generation of an anti saccade, ie a saccade towards the direction opposite to that of a visual stimulus, requires the correct function of special brain structures. In the present study attempts were made to measure the time consumption of brain processes preceding the execution of pro and anti saccades. The saccadic eye movements of five adult human subjects were investigated in a series of combined pro/anti saccade tasks with the aid of the gap and the overlap paradigms. The type of trial—pro saccade and anti saccade—was defined by the structure of the stimulus. In some sessions the subjects were, in addition, preinformed about the actual command by a cue at different lead times before stimulus onset. Pro-saccade and anti-saccade trials were randomly intermixed in equal proportions. High error rates (>30% of all trials in some subjects) occurred in the test sessions without preinformative cues. These errors had long reaction times (∼200 ms), whereas the latencies of correct pro or correct anti saccades were even longer (∼350 ms). Analysis of the errors revealed that they were related to the situation in the previous trial: a correct response in the previous trial enhanced the chance of making a saccade of the same type in the actual trial by up to 30%. This pretrial effect occurred whether the actual trial was a pro-saccade or an anti-saccade command. With a cue lead time of 100 ms the numbers of errors decreased, but the latencies of the correct pro or anti saccades were about 70 ms longer than those obtained in the nonrandom control. With a 200 ms cue lead time the reaction times corresponded to those in the control condition. The results suggest that the situation in a given trial creates a kind of default program for the saccade preparation in the next trial. When a cue about the actual command is given early enough, the default program is overridden correspondingly. The perception of the cue and the programming of the corresponding saccade takes an additional 150 to 200 ms.

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Smyrnis, N., T. Karantinos, I. Malogiannis, C. Theleritis, N. C. Stefanis, I. Evdokimidis, and I. Chatzimanolis. "386 – Larger unpredictability of saccadic reaction times in schizophrenic patients." Schizophrenia Research 98 (February 2008): 193. http://dx.doi.org/10.1016/j.schres.2007.12.453.

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BRAUN, D., H. WEBER, TH MERGNER, and J. SCHULTE-MÖNTING. "SACCADIC REACTION TIMES IN PATIENTS WITH FRONTAL AND PARIETAL LESIONS." Brain 115, no. 5 (1992): 1359–86. http://dx.doi.org/10.1093/brain/115.5.1359.

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Fischer, Burkhart, and Heike Weber. "Saccadic Reaction Times of Dyslexic and Age-Matched Normal Subjects." Perception 19, no. 6 (December 1990): 805–18. http://dx.doi.org/10.1068/p190805.

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Everling, S., P. Krappmann, A. Spantekow, and H. Flohr. "Influence of pre-target cortical potentials on saccadic reaction times." Experimental Brain Research 115, no. 3 (July 2, 1997): 479–84. http://dx.doi.org/10.1007/pl00005717.

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Koval, Michael J., Benson S. Thomas, and Stefan Everling. "Task-dependent effects of social attention on saccadic reaction times." Experimental Brain Research 167, no. 3 (November 11, 2005): 475–80. http://dx.doi.org/10.1007/s00221-005-0206-8.

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Ramon, Meike, Nayla Sokhn, and Roberto Caldara. "Decisional space modulates visual categorization – Evidence from saccadic reaction times." Cognition 186 (May 2019): 42–49. http://dx.doi.org/10.1016/j.cognition.2019.01.019.

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Ma, Liya, Janahan Selvanayagam, Maryam Ghahremani, Lauren K. Hayrynen, Kevin D. Johnston, and Stefan Everling. "Single-unit activity in marmoset posterior parietal cortex in a gap saccade task." Journal of Neurophysiology 123, no. 3 (March 1, 2020): 896–911. http://dx.doi.org/10.1152/jn.00614.2019.

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Abnormal saccadic eye movements can serve as biomarkers for patients with several neuropsychiatric disorders. The common marmoset ( Callithrix jacchus) is becoming increasingly popular as a nonhuman primate model to investigate the cortical mechanisms of saccadic control. Recently, our group demonstrated that microstimulation in the posterior parietal cortex (PPC) of marmosets elicits contralateral saccades. Here we recorded single-unit activity in the PPC of the same two marmosets using chronic microelectrode arrays while the monkeys performed a saccadic task with gap trials (target onset lagged fixation point offset by 200 ms) interleaved with step trials (fixation point disappeared when the peripheral target appeared). Both marmosets showed a gap effect, shorter saccadic reaction times (SRTs) in gap vs. step trials. On average, stronger gap-period responses across the entire neuronal population preceded shorter SRTs on trials with contralateral targets although this correlation was stronger among the 15% “gap neurons,” which responded significantly during the gap. We also found 39% “target neurons” with significant saccadic target-related responses, which were stronger in gap trials and correlated with the SRTs better than the remaining neurons. Compared with saccades with relatively long SRTs, short-SRT saccades were preceded by both stronger gap-related and target-related responses in all PPC neurons, regardless of whether such response reached significance. Our findings suggest that the PPC in the marmoset contains an area that is involved in the modulation of saccadic preparation. NEW & NOTEWORTHY As a primate model in systems neuroscience, the marmoset is a great complement to the macaque monkey because of its unique advantages. To identify oculomotor networks in the marmoset, we recorded from the marmoset posterior parietal cortex during a saccadic task and found single-unit activities consistent with a role in saccadic modulation. This finding supports the marmoset as a valuable model for studying oculomotor control.

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Berryhill, Marian, Kestutis Kveraga, and Howard C. Hughes. "Effects of Directional Uncertainty on Visually-Guided Joystick Pointing." Perceptual and Motor Skills 100, no. 1 (February 2005): 267–74. http://dx.doi.org/10.2466/pms.100.1.267-274.

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Reaction times generally follow the predictions of Hick's law as stimulus-response uncertainty increases, although notable exceptions include the oculomotor system. Saccadic and smooth pursuit eye movement reaction times are independent of stimulus-response uncertainty. Previous research showed that joystick pointing to targets, a motor analog of saccadic eye movements, is only modestly affected by increased stimulus-response uncertainty; however, a no-uncertainty condition (simple reaction time to 1 possible target) was not included. Here, we re-evaluate manual joystick pointing including a no-uncertainty condition. Analysis indicated simple joystick pointing reaction times were significantly faster than choice reaction times. Choice reaction times (2, 4, or 8 possible target locations) only slightly increased as the number of possible targets increased. These data suggest that, as with joystick tracking (a motor analog of smooth pursuit eye movements), joystick pointing is more closely approximated by a simple/choice step function than the log function predicted by Hick's law.

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Torbaghan, S. S., D. Yazdi, K. Mirpour, and J. W. Bisley. "Neural activity in the parietal priority map explains saccadic reaction times." Journal of Vision 11, no. 11 (September 23, 2011): 1343. http://dx.doi.org/10.1167/11.11.1343.

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Mahadevan, M., H. Bedell, and S. Stevenson. "The relationship between contrast detection and saccadic reaction times with attention." Journal of Vision 14, no. 10 (August 22, 2014): 332. http://dx.doi.org/10.1167/14.10.332.

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Bannerman, Rachel L., Maarten Milders, and Arash Sahraie. "Processing emotional stimuli: Comparison of saccadic and manual choice-reaction times." Cognition & Emotion 23, no. 5 (August 2009): 930–54. http://dx.doi.org/10.1080/02699930802243303.

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Leppänen, Jukka M., Linda Forssman, Jussi Kaatiala, Santeri Yrttiaho, and Sam Wass. "Widely applicable MATLAB routines for automated analysis of saccadic reaction times." Behavior Research Methods 47, no. 2 (May 2, 2014): 538–48. http://dx.doi.org/10.3758/s13428-014-0473-z.

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Weber, Heike, Monica Biscaldi, and Burkhart Fischer. "Intertrial effects of randomization on saccadic reaction times in human observers." Vision Research 35, no. 18 (September 1995): 2615–42. http://dx.doi.org/10.1016/0042-6989(95)00040-7.

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Adam, Ramina, Kevin Johnston, and Stefan Everling. "Recovery of contralesional saccade choice and reaction time deficits after a unilateral endothelin-1-induced lesion in the macaque caudal prefrontal cortex." Journal of Neurophysiology 122, no. 2 (August 1, 2019): 672–90. http://dx.doi.org/10.1152/jn.00078.2019.

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The caudal primate prefrontal cortex (PFC) is involved in target selection and visually guided saccades through both covert attention and overt orienting eye movements. Unilateral damage to the caudal PFC often leads to decreased awareness of a contralesional target alone, referred to as “neglect,” or when it is presented simultaneously with an ipsilesional target, referred to as “extinction.” In the current study, we examined whether deficits in contralesional target selection were due to contralesional oculomotor deficits, such as slower reaction times. We experimentally induced a focal ischemic lesion in the right caudal PFC of 4 male macaque monkeys using the vasoconstrictor endothelin-1 and measured saccade choice and reaction times on double-stimulus free-choice tasks and single-stimulus trials before and after the lesion. We found that 1) endothelin-1-induced lesions in the caudal PFC produced contralesional target selection deficits that varied in severity and duration based on lesion volume and location; 2) contralesional neglect-like deficits were transient and recovered by week 4 postlesion; 3) contralesional extinction-like deficits were longer lasting and recovered by weeks 8–16 postlesion; 4) contralesional reaction time returned to baseline well before the contralesional choice deficit had recovered; and 5) neither the mean reaction times nor the reaction time distributions could account for the degree of contralesional extinction on the free-choice task throughout recovery. These findings demonstrate that the saccade choice bias observed after a right caudal PFC lesion is not exclusively due to contralesional motor deficits, but instead reflects a combination of impaired motor and attentional processing. NEW & NOTEWORTHY Unilateral damage to the caudal prefrontal cortex in macaque monkeys results in impaired contralesional target selection during the simultaneous presentation of an ipsilesional target. We show that the recovery of contralesional target selection cannot be explained by the recovery of prolonged contralesional saccadic reaction times alone. This indicates that an impairment in contralesional attentional processing contributes to the magnitude of the saccade choice bias in the weeks following a unilateral caudal prefrontal cortex lesion.

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Sharika, K. M., Arjun Ramakrishnan, and Aditya Murthy. "Control of Predictive Error Correction During a Saccadic Double-Step Task." Journal of Neurophysiology 100, no. 5 (November 2008): 2757–70. http://dx.doi.org/10.1152/jn.90238.2008.

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We explored the nature of control during error correction using a modified saccadic double-step task in which subjects cancelled the initial saccade to the first target and redirected gaze to a second target. Failure to inhibit was associated with a quick corrective saccade, suggesting that errors and corrections may be planned concurrently. However, because saccade programming constitutes a visual and a motor stage of preparation, the extent to which parallel processing occurs in anticipation of the error is not known. To estimate the time course of error correction, a triple-step condition was introduced that displaced the second target during the error. In these trials, corrective saccades directed at the location of the target prior to the third step suggest motor preparation of the corrective saccade in parallel with the error. To estimate the time course of motor preparation of the corrective saccade, further, we used an accumulator model (LATER) to fit the reaction times to the triple-step stimuli; the best-fit data revealed that the onset of correction could occur even before the start of the error. The estimated start of motor correction was also observed to be delayed as target step delay decreased, suggesting a form of interference between concurrent motor programs. Taken together we interpret these results to indicate that predictive error correction may occur concurrently while the oculomotor system is trying to inhibit an unwanted movement and suggest how inhibitory control and error correction may interact to enable goal-directed behaviors.

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Rincon-Gonzalez, L., L. P. J. Selen, K. Halfwerk, M. Koppen, B. D. Corneil, and W. P. Medendorp. "Decisions in motion: vestibular contributions to saccadic target selection." Journal of Neurophysiology 116, no. 3 (September 1, 2016): 977–85. http://dx.doi.org/10.1152/jn.01071.2015.

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The natural world continuously presents us with many opportunities for action, and thus a process of target selection must precede action execution. While there has been considerable progress in understanding target selection in stationary environments, little is known about target selection when we are in motion. Here we investigated the effect of self-motion signals on saccadic target selection in a dynamic environment. Human subjects were sinusoidally translated (f = 0.6 Hz, 30-cm peak-to-peak displacement) along an interaural axis with a vestibular sled. During the motion two visual targets were presented asynchronously but equidistantly on either side of fixation. Subjects had to look at one of these targets as quickly as possible. With an adaptive approach, the time delay between these targets was adjusted until the subject selected both targets equally often. We determined this balanced time delay for different phases of the motion in order to distinguish the effects of body acceleration and velocity on saccadic target selection. Results show that acceleration (or position, as these are indistinguishable during sinusoidal motion), but not velocity, affects target selection for saccades. Subjects preferred to look at targets in the direction of the acceleration—the leftward target was preferred when the sled accelerated to the left, and vice versa. Saccadic reaction times mimicked this selection bias by being reliably shorter to targets in the direction of acceleration. Our results provide evidence that saccade target selection mechanisms are modulated by self-motion signals, which could be derived directly from the otolith system.

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Corneil, B. D., M. Van Wanrooij, D. P. Munoz, and A. J. Van Opstal. "Auditory-Visual Interactions Subserving Goal-Directed Saccades in a Complex Scene." Journal of Neurophysiology 88, no. 1 (July 1, 2002): 438–54. http://dx.doi.org/10.1152/jn.2002.88.1.438.

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This study addresses the integration of auditory and visual stimuli subserving the generation of saccades in a complex scene. Previous studies have shown that saccadic reaction times (SRTs) to combined auditory-visual stimuli are reduced when compared with SRTs to either stimulus alone. However, these results have been typically obtained with high-intensity stimuli distributed over a limited number of positions in the horizontal plane. It is less clear how auditory-visual interactions influence saccades under more complex but arguably more natural conditions, when low-intensity stimuli are embedded in complex backgrounds and distributed throughout two-dimensional (2-D) space. To study this problem, human subjects made saccades to visual-only (V-saccades), auditory-only (A-saccades), or spatially coincident auditory-visual (AV-saccades) targets. In each trial, the low-intensity target was embedded within a complex auditory-visual background, and subjects were allowed over 3 s to search for and foveate the target at 1 of 24 possible locations within the 2-D oculomotor range. We varied systematically the onset times of the targets and the intensity of the auditory target relative to background [i.e., the signal-to-noise (S/N) ratio] to examine their effects on both SRT and saccadic accuracy. Subjects were often able to localize the target within one or two saccades, but in about 15% of the trials they generated scanning patterns that consisted of many saccades. The present study reports only the SRT and accuracy of the first saccade in each trial. In all subjects, A-saccades had shorter SRTs than V-saccades, but were more inaccurate than V-saccades when generated to auditory targets presented at low S/N ratios. AV-saccades were at least as accurate as V-saccades but were generated at SRTs typical of A-saccades. The properties of AV-saccades depended systematically on both stimulus timing and S/N ratio of the auditory target. Compared with unimodal A- and V-saccades, the improvements in SRT and accuracy of AV-saccades were greatest when the visual target was synchronous with or leading the auditory target, and when the S/N ratio of the auditory target was lowest. Further, the improvements in saccade accuracy were greater in elevation than in azimuth. A control experiment demonstrated that a portion of the improvements in SRT could be attributable to a warning-cue mechanism, but that the improvements in saccade accuracy depended on the spatial register of the stimuli. These results agree well with earlier electrophysiological results obtained from the midbrain superior colliculus (SC) of anesthetized preparations, and we argue that they demonstrate multisensory integration of auditory and visual signals in a complex, quasi-natural environment. A conceptual model incorporating the SC is presented to explain the observed data.

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Johns, Murray, Kate Crowley, Robert Chapman, Andrew Tucker, and Christopher Hocking. "The effect of blinks and saccadic eye movements on visual reaction times." Attention, Perception, & Psychophysics 71, no. 4 (May 2009): 783–88. http://dx.doi.org/10.3758/app.71.4.783.

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Kurata, Kiyoshi, and Hiroshi Aizawa. "Influences of motor instructions on the reaction times of saccadic eye movements." Neuroscience Research 48, no. 4 (April 2004): 447–55. http://dx.doi.org/10.1016/j.neures.2004.01.003.

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Vavassis, A., M. von Grunau, and A. Johnson. "Saccadic reaction times in response to rewards of varying magnitude and probability." Journal of Vision 10, no. 7 (August 3, 2010): 248. http://dx.doi.org/10.1167/10.7.248.

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Diederich, Adele, Annette Schomburg, and Hans Colonius. "Saccadic Reaction Times to Audiovisual Stimuli Show Effects of Oscillatory Phase Reset." PLoS ONE 7, no. 10 (October 3, 2012): e44910. http://dx.doi.org/10.1371/journal.pone.0044910.

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Ramon, Meike, Nayla Sokhn, Junpeng Lao, and Roberto Caldara. "Decisional space determines saccadic reaction times in healthy observers and acquired prosopagnosia." Cognitive Neuropsychology 35, no. 5-6 (May 11, 2018): 304–13. http://dx.doi.org/10.1080/02643294.2018.1469482.

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Smith, Daniel T., and Soazig Casteau. "The effect of offset cues on saccade programming and covert attention." Quarterly Journal of Experimental Psychology 72, no. 3 (March 1, 2018): 481–90. http://dx.doi.org/10.1177/1747021818759468.

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Salient peripheral events trigger fast, “exogenous” covert orienting. The influential premotor theory of attention argues that covert orienting of attention depends upon planned but unexecuted eye-movements. One problem with this theory is that salient peripheral events, such as offsets, appear to summon attention when used to measure covert attention (e.g., the Posner cueing task) but appear not to elicit oculomotor preparation in tasks that require overt orienting (e.g., the remote distractor paradigm). Here, we examined the effects of peripheral offsets on covert attention and saccade preparation. Experiment 1 suggested that transient offsets summoned attention in a manual detection task without triggering motor preparation planning in a saccadic localisation task, although there were a high proportion of saccadic capture errors on “no-target” trials, where a cue was presented but no target appeared. In Experiment 2, “no-target” trials were removed. Here, transient offsets produced both attentional facilitation and faster saccadic responses on valid cue trials. A third experiment showed that the permanent disappearance of an object also elicited attentional facilitation and faster saccadic reaction times. These experiments demonstrate that offsets trigger both saccade programming and covert attentional orienting, consistent with the idea that exogenous, covert orienting is tightly coupled with oculomotor activation. The finding that no-go trials attenuates oculomotor priming effects offers a way to reconcile the current findings with previous claims of a dissociation between covert attention and oculomotor control in paradigms that utilise a high proportion of catch trials.

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Mullen, Sarah J., Yeni H. Yücel, Michael Cusimano, Tom A. Schweizer, Anton Oentoro, and Neeru Gupta. "Saccadic Eye Movements in Mild Traumatic Brain Injury: A Pilot Study OPEN ACCESS." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 41, no. 1 (January 2014): 58–65. http://dx.doi.org/10.1017/s0317167100016279.

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Objective:To investigate whether repeat saccadic reaction time (SRT) measurements using a portable saccadometer is useful to monitor patients with mild traumatic brain injury (mTBI).Methods:Seven patients with newly-diagnosed mTBI and five agematched controls were prospectively recruited from an emergency Department. Saccadic eye movements, symptom self-reporting and neuropsychological tests were performed within one week of injury and again at follow-up three weeks post-injury. Control patients underwent saccade recordings at similar intervals.Results:Median saccade reaction times were significantly prolonged within one week post-injury in mTBI compared to controls. At follow-up assessment there was no significant between-groups difference. Changes in median SRT between the two assessments were not statistically significant. Four of the seven mTBI patients showed significantly increased SRT at follow-up; three of the mTBI patients and all controls showed no significant change. Among the three mTBI patients with persistent decreased SRT, two experienced loss of consciousness and reported the greatest symptoms, while the third was the only subject with significant decrease in neuropsychological testing scores at both assessments.Conclusion:In three of seven mTBI patients, saccadic eye movements remained delayed within three weeks post-injury. These three patients also showed persistent symptoms or no improvement on neuropsychological testing. This pilot study using a portable saccadometer suggests that comparing SRT from three weeks post-injury to that within one week of injury may be useful for early detection of a subpopulation at risk of persistent disability from mTBI. This finding suggests that further investigation in a large study population is warranted.

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Bell, Andrew H., M. Alex Meredith, A. John Van Opstal, and Douglas P. Munoz. "Crossmodal Integration in the Primate Superior Colliculus Underlying the Preparation and Initiation of Saccadic Eye Movements." Journal of Neurophysiology 93, no. 6 (June 2005): 3659–73. http://dx.doi.org/10.1152/jn.01214.2004.

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Saccades to combined audiovisual stimuli often have reduced saccadic reaction times (SRTs) compared with those to unimodal stimuli. Neurons in the intermediate/deep layers of the superior colliculus (dSC) are capable of integrating converging sensory inputs to influence the time to saccade initiation. To identify how neural processing in the dSC contributes to reducing SRTs to audiovisual stimuli, we recorded activity from dSC neurons while monkeys generated saccades to visual or audiovisual stimuli. To evoke crossmodal interactions of varying strength, we used auditory and visual stimuli of different intensities, presented either in spatial alignment or to opposite hemifields. Spatially aligned audiovisual stimuli evoked the shortest SRTs. In the case of low-intensity stimuli, the response to the auditory component of the aligned audiovisual target increased the activity preceding the response to the visual component, accelerating the onset of the visual response and facilitating the generation of shorter-latency saccades. In the case of high-intensity stimuli, the auditory and visual responses occurred much closer together in time and so there was little opportunity for the auditory stimulus to influence previsual activity. Instead, the reduction in SRT for high-intensity, aligned audiovisual stimuli was correlated with increased premotor activity (activity after visual burst but preceding saccade-aligned burst). These data provide a link between changes in neural activity related to stimulus modality with changes in behavior. They further demonstrate how crossmodal interactions are not limited to the initial sensory activity but can also influence premotor activity in the SC.

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Iwasaki, Syoichi. "Facilitation of reaction times with GAP paradigm: comparison of manual and saccadic responses." Ergonomics 33, no. 6 (June 1990): 833–50. http://dx.doi.org/10.1080/00140139008927188.

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Taylor, M. J., R. H. S. Carpenter, and A. J. Anderson. "A noisy transform predicts saccadic and manual reaction times to changes in contrast." Journal of Physiology 573, no. 3 (June 7, 2006): 741–51. http://dx.doi.org/10.1113/jphysiol.2006.105387.

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Journal articles on the topic 'Saccadic Reaction Times'

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