optokinetic reflex test

Mice were handled and housed in accordance with the Johns Hopkins University Animal Care and Use Protocols and IACUC guidelines. Covering the entire right (contra) field had dramatically different consequences depending on stimulus direction (mask 7). ALiEM is not endorsed by, sponsored by, or affiliated with the University of California San Francisco or any institution. 7, C and D). 1972; Sun et al. 2009). Decreasing the contrast of the light and dark stripes progressively reduces the strength of the OKR with a threshold of detection (arbitrarily defined as greater than one ETM per 30 second interval) for C57BL/6J mice at 2% contrast and for 129/SvEv at 6% contrast (Figure 5A and Figure S2). Yes Elstrott J, Anishchenko A, Greschner M, Sher A, Litke AM, Chichilnisky EJ, Feller MB. Stimulation of the ipsi eye in its preferred direction (mask 7, T-N, magenta) resulted in around 22 OKR events (median), whereas N-T stimulation (mask 7, green) yielded only 2 (median; P = 0.0013). The set of masks (19) are represented as symbols at the bottom of Fig. If both reflexes are driven by the same detectors, what could be the conditions that result in the gain difference? The Optokinetic Reflex as a Tool for Quantitative Analyses of - PLOS In the present study we have chosen to induce the OKR with a continuously rotating stimulus, thereby inducing both slow (tracking) and fast (resetting) components. 3C, bottom). During OMR the mouse might observe the visual stimulus under a variety of angles, and with distinct relative contributions of the monocular and binocular fields of view, depending on the head angle under the yaw, pitch, and roll axes. Looking at these moving visual patterns normally induces nystagmus with the slow phase in the direction of the pattern movement. We previously demonstrated that a 14-day visuo-vestibular . A simple algorithm eliminates many of these artifacts by discounting all supra-threshold first derivative excursions in the correct direction that occur within 470 msecs of a supra-threshold excursion in the wrong direction. Genotypes are shown beneath panel (B). A radially symmetric image on the computer screen (e.g. In addition, preclinical CNS drug research could greatly . Eye Position indicates the horizontal difference between the center of the pupil and the center of the corneal reflection which shows a slow and uniform temporal-to-nasal motion interrupted approximately every two seconds by a rapid nasal-to-temporal saccade. The histograms in the lower panels of Figure 8A show the distribution of eye positions for the same intervals. OPK Tape | Optokinetic (OPK) Flags The optokinetic response (OKR) describes the preference of the fish to move its eyes in the direction of perceived motion and is the first visual behavior in the larva that requires form vision. Wallace DJ, Greenberg DS, Sawinski J, Rulla S, Notaro G, Kerr JN. At present, the nature of these genetic differences remains to be determined. 129/SvEv and C57BL/6J lines (rows 1 and 2) show characteristically different numbers of ETMs/second; lines with targeted gene mutations (rows 36 and 8) are maintained on mixed C57BL/6J129/SvEv backgrounds. Pupil constriction improves the accuracy of the calculation that identifies the center of the pupil. Most eye and head tracking phases cover 1 to 10 angular amplitude (Fig. OKN eye movements involve two phases: the first is smooth pursuit eye movements in the direction of the moving target and the second is nystagmus in the contralateral direction. 35). Given the various measurement constraints, this falls very close to unitary gain. The four templates were manually selected for each recording. This more complex response permits an assessment of changes in the frequency, amplitude, shape, and regularity of the alternating fast and slow components. (B) As for panel (A) but averaged data from eight Gnat1/;M pigment/L pigment heterozygous female mice. The optokinetic reflex | The Oxford Handbook of Eye Movements | Oxford During combined vestibular and optokinetic stimulation, which occurs during natural situations of self rotation, the optokinetic input takes over as the vestibular drive declines.1 When a continuously moving stimulus is viewed, a characteristic . Head and eye velocity ranges we recorded in unrestrained mice are consistent with the isolated head OMR and head-restrained eye OKR recordings (compare Fig. x + e. We used a degrees of freedom-adjusted R2 value to determine the goodness of fit. Figure 7A depicts the unfolded virtual sphere as projected onto our four screens in the recording setup and highlights the boundaries between presumed monocular and binocular fields of view (Bleckert et al. ALiEM Founder, Bridge to EM: Senior Medical Student Curriculum, GroundED in EM: A Third-Year Student Curriculum, EM Match Advice 40: Program Directors Reflect on the 2023 Match, EM Match Advice 39: Mailbag Q&A as a Mid-Interview Season Check-In, EM Match Advice Podcast: Mid-Interview Season Check-In | We want to hear from you. 2015). Other behaviors, such as those involved in learning and memory, can only be reliably assessed after a period of training. 1, BiBiii). The optokinetic nystagmus test measures the patient's ability to follow objects in motion with the eyes while the head remains stationary. The optokinetic reflex allows us to maintain foveation on a moving object when the head is stationary (ex., observing individual telephone poles on the side of the road as one travels by them in a car). The Optokinetic Reflex can be tested by passing an optokinetic tape in front of the patient's eyes, first in one direction and then in the other, and observing the motion of the eyes as the tape is passed. A relatively crude test of visual system function involves manually scoring the reflexive head turning that is elicited when an animal is placed in the center of a slowly rotating drum, a response that helps to stabilize the image of the drum on the retina [10], [11]. 8E; R2 for the linear regression line = 0.76). In contrast, OKR velocity is only slightly below stimulus velocity. 2010; van Alphen et al. Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America, Affiliations https://doi.org/10.1371/journal.pone.0002055.s001. The stimulus is controlled by a laptop computer and a projector, both of which sit approximately two meters above the drum on a rotating table that is controlled by a variable speed motor (not shown). . Competing interests: The authors have declared that no competing interests exist. . In our hands, stimulation of the recorded eye results in a moderate but consistent increase in OKR tracking compared with stimulation of the contralateral eye, even when the stimulus direction is optimal for the respective stimulated eye (e.g., masks 5 and 7 in T-N vs. masks 6 and 8 in N-T; P = 0.0013). The histograms were calculated using eye position values sampled at 60 Hz and processed as described under Experimental Procedures. Under scotopic conditions, the maximal amplitude of the OMRind in Brn3bKO/KO mice was drastically affected at full contrast (Fig. Figure 4J shows the fit curves for OKR gain, number and duration of tracking phases, and number of reset phases, corresponding to data in Fig. Most OKR movements are performed at 10/s, last 800 ms (median), and are followed by a fast reset movement (Fig. 2, C, D, G, and H; Kolmogorov-Smirnov test, at spatial frequency = 0.2 and contrast = 1, P = 0.0023). The spatial frequency dependency of OMR events paralleled the results seen for OKR, in terms of both curve shapes and absolute values, with the exception of gain, which was significantly lower (maximum = 0.3 OMR vs. 0.7 OKR; Fig. The standard black and white striped stimulus (Figure 2; 100% contrast) was modified by producing a weighted average between the black and white stripes and a standard grey with a luminance midway between that of the black and white stripes. We used fourth-order polynomial functions as optimal fits for the Brn3bWT/WT data shown in Fig. Sun LO, Brady CM, Cahill H, Al-Khindi T, Sakuta H, Dhande OS, Noda M, Huberman AD, Nathans J, Kolodkin AL. However, the similar tuning of OKR and OMR parameters to spatial frequency suggests that they derive their input from similarly tuned visual inputs (possibly ON-DS RGCs). At optimal spatial frequencies (0.2 cycle/), tracking phases were more numerous, much faster (gain 0.7 in median), shorter (2 s), and typically followed by a fast phase (Fig. Oyster CW, Simpson JI, Takahashi ES, Soodak RE. The ISCAN software has assigned the IR sink as the pupil and the IR peak as the corneal reflection. C57BL/6J mice are somewhat more sensitive than 129/SvEv to high spatial frequencies, as seen in comparing the OKR to 1 stripes. 6, A and B, example 1) and less common trials during which eye or head were able to better keep up with stimulus velocity (Fig. Outside the optimum, the number of movements declined, and they became longer and slower, and were rarely followed by fast phases (Fig. We have recently proposed an unbiased approach in which angular head velocities are recorded for all frames of the recording, and then a overall direction bias, which we call OMR index (OMR, see material and methods and Fig. The responses decreased toward both higher and lower spatial frequencies, and at 0.4 cycle/, both Brn3bWT/WT and Brn3bKO/KO mice moved the same amount of time in the correct and in the incorrect directions (ratio = 1). Vestibulo-ocular reflex - Wikipedia Optokinetic reflex Optokinetic nystagmus can be induced with an optokinetic drum, a banded cloth, a tablet application, or simply with the examiner moving the outstretched fingers in front of the patient. For OMR, the automated OMRind (Fig. approved final version of manuscript. The left-most data points in each curve correspond to the start of the slow phase. Phenobarbital as First-Line Medication for Alcohol Withdrawal: Have You Switched From Benzodiazepines Yet? Substantial variations have been reported in OKR response amplitudes in various inbred strains of mice [20], [21]. In mice, OMR are relatively easy to observe and find broad use in the rapid evaluation of visual function. conceived and designed research; F.K., M.T., and B.W. broad scope, and wide readership a perfect fit for your research every time. [34], neither of these conditions apply, but in practice the proportionality is still reasonably constant over different angles of deflection because the two principal deviations from the ideal casenamely, (1) the rotation of the eye around a point behind the center of the globe, and (2) the position of the pupil behind the corneal surfaceproduce largely compensating errors. 6, C, D, F, and G). The resulting distributions demonstrate that this characteristic is inherited as a polygenic trait, as judged by the relatively narrow distribution of ETMs in the F2 generation. 2, A, C, E, and G). For OMR curves: number of tracking phases (black; data from E), R2 = 0.80; OMRind (blue; data from G), R2 = 0.72; gain of OMR (purple; data from G), R2 = 0.46; duration of OMR phases (red; data from F), R2 = 0.79. It appears that for small stimulus angular amplitudes (20), mice prefer to follow the stimulus with uninterrupted slow (tracking) phases, akin to our type I movements. Many commonly used behavioural assays of visual function, such as pupil constriction 8, optokinetic and optomotor reflexes 9, 10, suffer from the same weakness; being sub-conscious, reflex. Rows 1 and 2 show responses to standard clockwise or counterclockwise rotation. 4E), and the duration of these phases (Fig. The head gain remains relatively constant (0.25) in the spatial frequency range of 0.1 to 0.3 cycle/ and only drops to 0.15 at the edges of the spatial frequency range with the goodness of fit being much worse than for the other parameters. Standard anatomical and visual space for the mouse retina: computational reconstruction and transformation of flattened retinae with the Retistruct package. Professor of Emerg Med at UCSF-Zuckerberg SF General. Although OKR signal-to-noise ratios are much better, we show that OMR can yield similar results without the need for invasive procedure, fixation of the animal, or calibration procedures. 4A), with individual tracking phases essentially covering the entire unidirectional stimulus epoch (Figs. Mean +/ standard deviation for >6 mice for each strain and 2539 30-second stimulus intervals per condition. However, our mutants preserve spatial frequency tuning for both OKR and OMR. For monocular stimulation, an opaque panel was placed over one-half of the test cylinder. Optokinetic Drum - an overview | ScienceDirect Topics Conceived and designed the experiments: JN HC. Trick of Trade: Dual Foley catheter to control massive epistaxis, Trick of Trade: Removal of Entrapped Metal Zipper, PECARN Pediatric Head Trauma: Official Visual Decision Aid, A Starters Roadmap to EM Resources: Books, Websites, and Apps, D50 vs D10 for Severe Hypoglycemia in the Emergency Department, The Dirty Epi Drip: IV Epinephrine When You Need It, Tips for Interpreting the CSF Opening Pressure, Trick of the Trade: Mix Ceftriaxone IM with Lidocaine for Less Pain, Trick of the Trade: Urine Pregnancy Test Without Urine, Wellness and Resiliency during Residency: EM is a career with unresolved stories, Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License, Academic Life in Emergency Medicine - All Rights Reserved (except for the PV Cards and MEdIC Series PDFs). We therefore reevaluated the stimulus speed dependency of OMR and OKR gain under maximal contrast and optimal spatial frequency (0.2 cycle/) conditions. Compensatory eye (optokinetic response, OKR) and/or head (optomotor response, OMR) reflexes integrate information from the global shift of the visual image over the retina. One barrier to the wider use of mouse oculomotor testing, as currently practiced, is its relatively low throughput; as a consequence, it has not been included among the neurologic tests used in conjunction with any of the large scale chemical mutagenesis screens [32], [33]. Supplementary Movies S3 and S4 show examples of the lateral camera recording of a mouse performing head and eye tracking simultaneously. 8C and Fig. Consistent with this observation, ablating cones with diphtheria toxin, while leaving the ipRGC system intact, does not eliminate the photopic OKR (Figure 3A, line 7) unless rod function is eliminated (Figure 3A, line 8) or the pupils are dilated pharmacologically (data not shown). Contrast and spatial frequency thresholds have been measured by visual inspection of head and body turning in freely moving mice (the optomotor response)[11]. An argument for alternative RGCs being involved is that the type I movements are also present in wild-type mice, at suboptimal but also optimal stimulation conditions. An interesting observation to us is that slow (tracking) phases for head movements during OMR and to a lesser degree for eye movements during head-fixed OKR can exhibit heterogeneity with regard to velocity, duration, and presence or absence of the reset (fast) phase (examples in Fig. N, nasal; T, temporal. You suspect a psychiatric or malingering etiology, but arent sure. 4). In Brn3bWT/WT OKR, slow tracking phases of very low gain (0.1 in median) occurred continuously at low spatial frequencies up to 0.05 cycle/ (Fig. The optokinetic reflex (OKR), which serves to stabilize a moving image on the retina, is a behavioral response that has many favorable attributes as a test of CNS function. Time derivatives and thresholding operations were performed in Excel. To collect OKR data, the eye was imaged through a small hole cut in the poster paper using infrared illumination and an ISCAN (Burlington, MA) infrared video camera. (Kretschmer et al. The variation of head and eye movement participation and gain could be explained by alternation between different viewing modes (Dawkins 2002) and could be affected by the level of attention and the behavioral context (see Maurice and Gioanni 2004 for examples in pigeons). We have used this system to (1) define the basic OKR stimulus-response characteristics of C57BL/6J and 129/SvEv and of genetically engineered variants that lack one or more photoreceptor systems or that have an altered spectral sensitivity, (2) show that the characteristic difference in OKR frequency between C57BL/6J and 129/SvEv is inherited as a polygenic trait, and (3) demonstrate that the mouse OKR can be used as a sensitive and quantitative assay for drug action in the CNS. As an initial test of this idea, we have examined the time course of ketamine action on the mouse OKR following intraperitoneal (IP) delivery (Figure 8). Under photopic conditions, the OMRind dependency on spatial frequency in Brn3bWT/WT mice is similar to previously published observations (Prusky et al. No, Is the Subject Area "Mice" applicable to this article? Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is an autosomal recessive adult-onset, slowly progressive neurologic disorder characterized by imbalance due to cerebellar gait and limb ataxia, impaired vestibular function bilaterally, and non-length-dependent sensory neuropathy (summary by Szmulewicz et al., 2011 ). Prusky GT, Alam NM, Beekman S, Douglas RM. We note that type I tracking (slow) phases can also be seen for head-fixed OKR, predominantly under suboptimal stimulus conditions. Mice alternate between type I responses, consisting of low-gain, continuous head tracking phases in stimulus direction, amounting to small angular excursions and uninterrupted by reset phases, and type II responses, consisting of shorter, faster head tracking phases that are followed by reset phases, essentially resembling classic OKR eye movements (equivalent to a head nystagmus). However, it has an unexpectedly large contribution to the OKR compared with its size relative to the monocular fields. Note that whereas eyes are almost continuously engaged in OKR events, clear head OMR episodes are noticeable between seconds 25 and 1113 of the movie. Given the pendular movement of our stimulus, which reverses direction every 5 s, the maximum duration of a tracking phase is 5 s. The plateau of the duration from 0.3 to 0.425 cycle/ (Fig. Simultaneous eye and head measurements were recorded from unrestrained animals placed on the platform in the OMR configuration, with an additional lateral camera (Pro 9000; Logitech, Lausanne, Switzerland) placed on one of the arena walls elevated ~12 cm above the mouse platform (Fig. The coordinates with the highest correlations were then calculated for the pupil positions and reference locations. https://doi.org/10.1371/journal.pone.0002055.g002. 1Cii) were detected using a template-matching algorithm based on a normalized cross-correlation (see expanded/corrected version of Lewis 2007; http://scribblethink.org/Work/nvisionInterface/nip.pdf), which was applied to a manually defined region of interest. On the basis of the annotated onsets and offsets, we then calculated the number of occurring tracking phases and their duration, velocity, and gain (Fig. Dizziness and vertigo are some of the more frequently encountered symptoms in neurology clinics. interpreted results of experiments; F.K., M.T., and T.C.B. The first derivative of eye position is shown above a pair of traces that indicate the times at which the first derivative exhibits an excursion below or above negative or positive thresholds, respectively. Five intervals from a single experiment are shown in the upper panels of Figure 8A. However, it should be noted that most curve fits for OMRind in Brn3bKO/KO mice under scotopic conditions were relatively poor (R2 0.2; Supplementary Table S1 and Fig. Copyright: 2008 Cahill, Nathans. 3, green and magenta lines, respectively). The OKR requires no training, assesses the function of diverse CNS circuits, can be induced repeatedly with minimal fatigue or adaptation, and produces an electronic record that is readily and objectively quantifiable. The vestibulo-ocular reflex adjusts our eye position to offset head movements. We have found that mouse OMR and OKR tuning for stimulus speed and spatial frequency are in good agreement for most parameters investigated, but that OMR gain is significantly lower than OKR gain under all stimulation conditions. Both reflexes are crucial to survival. Before recording began, each mouse eye was calibrated using a variant of the procedure previously described by Stahl et al. After manually annotating the traces, we calculated the duration and velocity of all occurring tracking phases. No, Is the Subject Area "Pigments" applicable to this article? Contactin-4 mediates axon-target specificity and functional development of the accessory optic system. For example, the OKR could be used to quantify drug-induced sedation or arousal, or to monitor the progression or the therapeutic response of neurodegenerative disease. Comparison of optomotor and optokinetic reflexes in mice Wild type mice express two types of cone pigment: an S pigment, with maximal absorption at 360 nm, and an M pigment, with maximal absorption at 510 nm [43]. Eye movements of the murine P/Q calcium channel mutant tottering, and the impact of aging, A comparison of video and magnetic search coil recordings of mouse eye movements. Optokinetic Stimulation As a Treatment for Imbalance With Ve - Lww (N=2224 ETMs/averaged curve, obtained from 3 mice. The interpolated grey intensity that yields the fewest ETMs per 30 seconds provides the best estimate of the psychophysical null point. VisualEyes | Optokinetic Nystagmus Test | Interacoustics (2015). The two eyes perform synchronized tracking phases, followed by fast reset phases, whereas the head moves in stimulus direction at a very low gain. 2014). For larger mammals, including humans, it has long been appreciated that these criteria are met by the OKR and the VOR [16], [18], [19]. https://doi.org/10.1371/journal.pone.0002055.g003. As both of these variations are barely noticeable to a human observer, we have not attempted to correct them. I asked her if she wanted to see a psychiatrist. Funding: H.C. and J.N. Optokinetic response - Wikipedia https://doi.org/10.1371/journal.pone.0002055, Editor: Daphne Soares, University of Maryland, United States of America, Received: January 7, 2008; Accepted: February 27, 2008; Published: April 30, 2008. These examples suggest that the murine OKR could be usefully applied to a wide variety of investigations. 8C), whereas the correlation between angles covered by the two eyes during coincident OKR movements is reasonably high (Fig. HHS Vulnerability Disclosure, Help The effects of the left or right monocular hemifield occlusions were even more pronounced, reducing the number of OKR phases to almost half compared with the unmasked condition, under either T-N or N-T stimulation. Larger excursions arise from errors in the automated assignment of pupil location.
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