Distribution of Quick-Phase Intervals in Optokinetic Nystagmus

Carpenter, R. H. S.

doi:10.1159/000267270

Cited by 11 publications

(9 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The start of a QP is determined by the saccadic trigger, which could be determined by SP duration (Anastasio, 1996;Carpenter, 1993Carpenter, , 1994, eye position (Chun & Robinson, 1978), or a combination of processes (Balaban & Ariel, 1992). Our results indicate that the threshold is dependent on both the SP start position and SP velocity and cannot be determined solely by position or duration.…”

Section: Discussionmentioning

confidence: 72%

“…SPs are slow movements made in the direction of stimulus motion with a gain (SP speed ‚ stimulus speed) less than unity, which decreases with stimulus speed (Fletcher, Hain, & Zee, 1990) so complete retinal stabilization is seldom achieved. SPs tend to bring the eye position to a more central location, but the timing and amplitude of both SPs and QPs are highly variable (Anastasio, 1996;Balaban & Ariel, 1992;Carpenter, 1993Carpenter, , 1994Cheng & Outerbridge, 1974;Trillenberg, Zee, & Shelhamer, 2002). This variability is intrinsic and implies either an embedded stochastic process or complicated deterministic behavior manifesting as chaos.…”

Section: Introductionmentioning

confidence: 99%

“…Although much is known about the neural circuitry involved in generating saccades, the mechanism that determines when a QP is triggered and its target position is not well understood. However, the timing of QPs is often modeled as a stochastic signal accumulating information (or integrating neural activity) to a threshold, at which time a QP is generated (Anastasio, 1996;Balaban & Ariel, 1992;Carpenter, 1993Carpenter, , 1994Trillenberg et al, 2002). Recently, we compared six of these accumulator models and found that the best fitting distribution to QP interval histograms was given by the ratio of two correlated random variables (Waddington & Harris, 2012).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Human optokinetic nystagmus: A stochastic analysis

Waddington

Harris

2012

Journal of Vision

View full text Add to dashboard Cite

Optokinetic nystagmus (OKN) is a fundamental gaze-stabilizing response found in almost all vertebrates, in which eye movements attempt to compensate for the optic flow caused by self-motion. It is an alternating sequence of slow compensatory eye movements made in the direction of stimulus motion and fast eye movements made predominantly in the opposite direction. The timing and amplitude of these slow phases (SPs) and quick phases (QPs) are remarkably variable, and the cause of this variability is poorly understood. In this study principal components analysis was performed on OKN data to illustrate that the variability in correlation matrices across individuals and recording sessions reflected changes in the noise in the system while the linear relationships between variables remained predominantly the same. Three components were found that could explain the variance in OKN data, and only variables from within a single cycle contributed highly to any given component. A linear stochastic model of OKN was developed based on these results that describes OKN as a triple first order Markov process, with three sources of noise affecting SP velocity, the QP trigger, and QP amplitude. This model was used to predict the degree of signal dependent noise in the system, the duration of the transient state of SP velocity, and an apparent undershoot bias to the QP target location.

show abstract

Section: Discussionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Human optokinetic nystagmus: A stochastic analysis

Waddington

Harris

2012

Journal of Vision

View full text Add to dashboard Cite

show abstract

“…Although our data did not allow us to determine when the programming of corrective saccades actually begins, we can still use the intersaccadic interval to compare the decision time of corrective saccades in the three different stimulus conditions assuming the programming begins at the same time. In addition, it has been demonstrated that the intersaccadic intervals of spontaneous saccades, such as in reading or optokinetic nystagmus (OKN), can be well described by the LATER model (Carpenter, 1993, Carpenter & McDonald, 2007). Interestingly, the latencies of corrective saccades in our experiments showed similar patterns of distribution to the intersaccadic intervals for those more “spontaneous”, reflexive saccades, with longer median latencies and more of the early latency saccades than those of visually-triggered saccade.…”

Section: Discussionmentioning

confidence: 99%

Revisiting corrective saccades: Role of visual feedback

2013

View full text Add to dashboard Cite

To clarify the role of visual feedback in the generation of corrective movements after inaccurate primary saccades, we used a visually-triggered saccade task in which we varied how long the target was visible. The target was on for only 100 ms (OFF100ms), on until the start of the primary saccade (OFFonset) or on for 2 s (ON). We found that the tolerance for the post-saccadic error was small (− 2%) with a visual signal (ON) but greater (−6%) without visual feedback (OFF100ms). Saccades with an error of −10%, however, were likely to be followed by corrective saccades regardless of whether or not visual feedback was present. Corrective saccades were generally generated earlier when visual error information was available; their latency was related to the size of the error. The LATER (Linear Approach to Threshold with Ergodic Rate) model analysis also showed a comparable small population of short latency corrective saccades irrespective of the target visibility. Finally, we found, in the absence of visual feedback, the accuracy of corrective saccades across subjects was related to the latency of the primary saccade. Our findings provide new insights into the mechanisms underlying the programming of corrective saccades: 1) the preparation of corrective saccades begins along with the preparation of the primary saccades, 2) the accuracy of corrective saccades depends on the reaction time of the primary saccades and 3) if visual feedback is available after the initiation of the primary saccade, the prepared correction can be updated.

show abstract

“…Our results showing a degree of integration between saccades and the slow phases of OKN are consistent with previous research showing integration and similarities between saccades and the fast phases of OKN. Saccades and fast phases have a very similar main sequence (Guitton & Mandl, 1980) and latency distributions (Carpenter, 1993;Carpenter, 1994;Roos, Calandrini, & Carpenter, 2008) and can be modeled by accumulator models that were originally designed for saccades (Carpenter & Williams, 1995;Roos et al, 2008). Saccades and fast phases both suffer the saccadic inhibition effect produced by irrelevant visual stimuli, and interact to produce targeting saccades that are curved (Harrison et al, 2014).…”

Section: Okn Fast Phases and Saccadesmentioning

confidence: 99%

Saccadic compensation for reflexive optokinetic nystagmus just as good as compensation for volitional pursuit

Harrison¹,

Freeman²,

Sumner³

2015

Journal of Vision

View full text Add to dashboard Cite

The natural viewing behavior of moving observers ideally requires target-selecting saccades to be coordinated with automatic gaze-stabilizing eye movements such as optokinetic nystagmus. However, it is unknown whether saccade plans can compensate for reflexive movement of the eye during the variable saccade latency period, and it is unclear whether reflexive nystagmus is even accompanied by extraretinal signals carrying the eye movement information that could potentially underpin such compensation. We show that saccades do partially compensate for optokinetic nystagmus that displaces the eye during the saccade latency period. Moreover, this compensation is as good as for displacements due to voluntary smooth pursuit. In other words, the saccade system appears to be as well coordinated with reflexive nystagmus as it is with volitional pursuit, which in turn implies that extraretinal signals accompany nystagmus and are just as informative as those accompanying pursuit.

show abstract

Distribution of Quick-Phase Intervals in Optokinetic Nystagmus

Cited by 11 publications

References 4 publications

Human optokinetic nystagmus: A stochastic analysis

Human optokinetic nystagmus: A stochastic analysis

Revisiting corrective saccades: Role of visual feedback

Saccadic compensation for reflexive optokinetic nystagmus just as good as compensation for volitional pursuit

Contact Info

Product

Resources

About