A high-resolution binocular video-oculography system: assessment of pupillary light reflex and detection of an early incomplete blink and an upward eye movement

Background: The pupillary light reflex characterizes the direct and consensual response of the eye to the perceived brightness of a stimulus. It has been used as indicator of both neurological and optic nerve pathologies. As with other eye reflexes, this reflex constitutes an almost instantaneous movement and is linked to activation of the same midbrain area. The latency of the pupillary light reflex is around 200 ms, although the literature also indicates that the fastest eye reflexes last 20 ms. Therefore, a system with sufficiently high spatial and temporal resolutions is required for accurate assessment. In this study, we analyzed the pupillary light reflex to determine whether any small discrepancy exists between the direct and consensual responses, and to ascertain whether any other eye reflex occurs before the pupillary light reflex. Methods: We constructed a binocular video-oculography system two high-speed cameras that simultaneously focused on both eyes. This was then employed to assess the direct and consensual responses of each eye using our own algorithm based on Circular Hough Transform to detect and track the pupil. Time parameters describing the pupillary light reflex were obtained from the radius time-variation. Eight healthy subjects (4 women, 4 men, aged 24–45) participated in this experiment. Results: Our system, which has a resolution of 15 microns and 4 ms, obtained time parameters describing the pupillary light reflex that were similar to those reported in previous studies, with no significant differences between direct and consensual reflexes. Moreover, it revealed an incomplete reflex blink and an upward eye movement at around 100 ms that may correspond to Bell’s phenomenon. Conclusions: Direct and consensual pupillary responses do not any significant temporal differences. The system and method described here could prove useful for further assessment of pupillary and blink reflexes. The resolution obtained revealed the existence reported here of an early incomplete blink and an upward eye movement.

The laboratory assessment of thyroid function with special reference to the importance of thyroid abnormality in psychiatric disease

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A linear chromatic mechanism drives the pupillary response

Previous studies have shown that a chromatic mechanism can drive pupil responses. The aim of this research was to clarify whether a linear or nonlinear chromatic mechanism drives pupillary responses by using test stimuli of various colours that are defined in cone contrast space. The pupil and accommodation responses evoked by these test stimuli were continuously and simultaneously objectively measured by photorefraction. The results with isochromatic and isoluminant stimuli showed that (lie accommodative level remained approximately constant (<0.25 D change in mean level) even when the concurrent pupillary response was large (ca. 0.30mm). The pupillary response to an isoluminant grating was sustained, delayed by ca. 60 ms) and larger in amplitude than that for a isochromatic uniform stimulus, which supports previous work suggesting that the chromatic mechanism contributes to the pupillary response. In a second experiment, selected chromatic test gratings were used and isoresponse contours in cone contrast space were obtained. The results showed that the isoresponse contour in cone contrast space is well described (r2 = 0.99) by a straight line with a positive slope. The results indicate that a [L-M] linear chromatic mechanism, whereby a signal from the long wavelength cone is subtracted from that of the middle wavelength cone and vice versa, drives pupillary responses.

Abnormality of mismatch negativity in response to tone omission in dyslexic adults

Evidence of abnormalities in the perception of rapidly presented sounds in dyslexia has been interpreted as evidence of a prolonged time window within which sounds can influence the perception of temporally surrounding sounds. We recorded the magnetic mismatch negativity (MMNm) to infrequent tone omissions in a group of six dyslexic adults and six IQ and age-matched controls. An MMNm is only elicited in response to a complete stimulus omission when successive inputs fall within the temporal window of integration (stimulus onset asynchrony (SOA) ∼160 ms). No MMNm responses were recorded in either experimental group when stimuli were presented at SOAs falling just outside the temporal window of integration (SOA = 175 ms). However, while presentation rates of 100 ms resulted in MMNm responses for all control participants, the same stimulus omissions elicited an MMNm response in only one of the six dyslexic participants. These results cannot support the hypothesis of a prolonged time window of integration, but rather indicate auditory grouping deficits in the dyslexic population. © 2006 Elsevier B.V. All rights reserved.

The pupillary light reflex in migraine

The literature suggests that there may be pupil size and response abnormalities in migraine headache sufferers. We used an infra-red pupillometer to measure dynamic pupil responses to light in 20 migraine sufferers (during non-headache periods) and 16 non-migraine age and gender matched controls. There was a significant increase in the absolute inter-ocular difference of the latency of the pupil light response in the migraine group compared with the controls (0.062 s vs 0.025 s, p = 0.014). There was also a significant correlation between anisocoria and lateralisation of headache such that migraine sufferers with a habitual head pain side have more anisocoria (r= 0.59, p < 0.01), but this was not related to headache laterally. The pupil changes were not correlated with the interval since the last migraine headache, the severity of migraine headache or the number of migraine headaches per annum. We conclude that subtle sympathetic and parasympathetic pupil abnormalities persist in the inter-ictal phase of migraine. © 2005 The College of Optometrists.

Pupillary behavior in relation to wavelength and age

Pupil light reflex can be used as a non-invasive ocular predictor of cephalic autonomic nervous system integrity. Spectral sensitivity of the pupil's response to light has, for some time, been an interesting issue. It has generally, however, only been investigated with the use of white light and studies with monochromatic wavelengths are scarce. This study investigates the effects of wavelength and age within three parameters of the pupil light reflex (amplitude of response, latency, and velocity of constriction) in a large sample of younger and older adults (N = 97), in mesopic conditions. Subjects were exposed to a single light stimulus at four different wavelengths: white (5600° K), blue (450 nm), green (510 nm), and red (600 nm). Data was analyzed appropriately, and, when applicable, using the General Linear Model (GLM), Randomized Complete Block Design (RCBD), Student's t-test and/or ANCOVA. Across all subjects, pupillary response to light had the greatest amplitude and shortest latency in white and green light conditions. In regards to age, older subjects (46-78 years) showed an increased latency in white light and decreased velocity of constriction in green light compared to younger subjects (18-45 years old). This study provides data patterns on parameters of wavelength-dependent pupil reflexes to light in adults and it contributes to the large body of pupillometric research. It is hoped that this study will add to the overall evaluation of cephalic autonomic nervous system integrity.

On point estimation of the abnormality of a Mahalanobis index

Open Access funded by Medical Research Council Acknowledgment The work reported here was funded by a grant from the Medical Research Council, UK, grant number: MR/J013838/1.

Pupillary shapes in response to electrical stimulation of the sclera of peripheral cornea in cats and porcines

Purpose: We have reported that the changes in the pupillary shape in response to electrical stimulation of the branches of the ciliary nerves in cats. (Miyagawa et al. PLoS One, 2014). This study investigates the changes in the pupillary shapes in response to electrical stimulations of the sclera of peripheral cornea in cats and porcines. Methods: Two enucleated eyes of two cats and three enucleated porcine eyes were studied. Trains of biphasic pulses (current, 3 mA; duration, 2 ms/phase; frequency, 40 Hz) were applied using a tungsten electrode (0.3mm diameter). The stimulation was performed at every 45 degree over the entire circular region on the sclera near the cornea. The pupillary images were recorded before and 4 s (cat) and 10 s (pig) after the stimulation and the change in the pupil diameter (Δr) was quantified. The pupillary images were obtained with a custom-built compact wavefront aberrometer (Uday et al. J Cataract Refract Surg, 2013). Results: In a cat eye, the pupil was dilated by the electrical stimulation at six out of eight orientations (before stimulation pupil diameter r=10.10±0.49 mm, Δr=0.33±0.12 mm). The pupil dilated only toward the electrode (relative eccentricity of the pupil center to the pupil diameter change amount rdec=1.15±0.28). In the porcine eyes, the pupils were constricted by the electrical stimulations at the temporal and nasal orientations (r=10.04±0.57 mm, Δr=1.52±0.70 mm). The pupils contracted symmetrically (rdec=0.30±0.12). Conclusions: With electrical stimulation in the sclera of the peripheral cornea, asymmetric mydriasis in cat eyes and symmetrical miosis in porcine eyes were observed. Under the assumption that the electrical stimulation stimulated both muscles that contribute to the pupil control, our hypothesis proposed here is that the pupil dilator is stronger than the pupil sphincter in cat, and pupil sphincter is stronger than pupil dilator in porcine.

The effect of Physiological NaCl Dilution levels and Storage Duration to Sperm Motility and Abnormality in Muscovy Duck

The aim of this research are to know the effects of physiological NaCl dilution levels and storage duration on sperm motility and abnormality of  Muscovy duck. Materials which used in this research were semen that collected of 1  - 1,5 years of four Muscovy duck. Semen were treated by physiological NaCl dilution levels nol , three, six and nine and storage duration ( t0 = 0 minute t1 =45minutes and t2=90 minute). Replication was three tapping periode . The method of this research was laboratory experimental with Randomized Complete Blok Design (RBD) in Split Plot Design (SPD)  pattern ,as main plot is Physiological NaCl dilation levels and as sub plot is storage duration. Result of the experiment showed that physiological NaCl dilution levels was very significantly influences on sperm motility (p<0,01) and significantly influences and sperm abnormality (p<0,05) . The storage duration was very significantly influences and sperm motility and abnormality (p<0,01) .Orthogonal duration polynomial assayed showed that the effect of physiological NaCl dilution levels to sperm motility  had a linier regression line with the a equation as Y =69.94 - 2.65 X,  r=0,49 R2=0.24 with Y presented to sperm motility and X represented to physiological NaCl dilution levels  sperm and effect of storage duration to sperm motility had a linier regression line with the equation as Y =74.24-0.35 X, r =0.73 R2=0.53 with Y represented to sperm motility and X represented to storage duration . The effect of physiological NaCl dilution levels to sperm abnormality had a linier regression line with the equation as Y =5.61+0.34X, r=0.52 R2=0.27 with Y represented to sperm to abnormality and X represented to regression line with the equation as Y =6.74+0.01X, r=0.24R2=0.060 with Y represented to sperm abnormality and X represented to storage duration. It is can be concluded that a higher physiological NaCl dilation levels and storage duration caused sperm to motility decreased and sperm abnormality increased. (Animal Production 3(2): 45-52 (2001)Key Word: sperm Muscovy duck.

The Effect of Level Testosteron e Addition in Diluents and Level Dilution on Speed Movement and Abnormality of Kedu Chicken Sperm

The research entitled “The Effect of Level Testosterone Addition in Diluents and Level Dilution on Speed Movement and Abnormality of Kedu Chicken Sperm” was conducted in Laboratory of Physiology and Reproduction, Faculty of Animal Science, UNSOED, started at August 15th to September 15th , 2001. The aims of  this research were to obtain influences of level testosterone and dilution on speed movement and secondary abnormality kedu chicken sperm and obtain interaction between the treatments. The tapped sperm from nine kedu chickens were used in this research. This Experiment was performed 4 x 3 Factorials with Randomized  Completely Block Design (RCBD) as the basic design. The treatment combinations were level testosterone 0, 300, 600 and 900 μg (t0, t1, t2 and t3) and level of dilution 4, 6 and 8 time (in a row p1, p2 and p3). The tapping period was replicated four times as a group (replicated) with two days interval. The result of this research showed that the interaction between level of testosterone addition and level of dilution gave a non-significant effect to speed movement sperm but significant to abnormality of kedu chicken sperm. The group gave a significant influence (P<0.05) to speed movement sperm and non significant to sperm abnormality. The interaction of level testosterone addition and level dilution of kedu chicken semen (T x P) has a quadratic regression to sperm abnormality with regression comparison is Y = 24.418 – 0.014 X +1.187E – 05 X², with peak point is (543.76: 20.23) of correlation coefficient (r) 0.55 and determination coefficient (R²) as 30.34%. The addition of 600 μg testosterone level with 6 level dilutions was the best to defend sperm abnormality. (Animal Production 4(2): 60-70 (2002) Key Words : Spermatozoa, Kedu Chicken, Testosterone, Dilution, Speed Movement and Abnormality

Aberrations and pupil location under corneal topography and Hartmann-Shack illumination conditions

PURPOSE. This study was conducted to determine the magnitude of pupil center shift between the illumination conditions provided by corneal topography measurement (photopic illuminance) and by Hartmann-Shack aberrometry (mesopic illuminance) and to investigate the importance of this shift when calculating corneal aberrations and for the success of wavefront-guided surgical procedures. METHODS. Sixty-two subjects with emmetropia underwent corneal topography and Hartmann-Shack aberrometry. Corneal limbus and pupil edges were detected, and the differences between their respective centers were determined for both procedures. Corneal aberrations were calculated using the pupil centers for corneal topography and for Hartmann-Shack aberrometry. Bland-Altmann plots and paired t-tests were used to analyze the differences between corneal aberrations referenced to the two pupil centers. RESULTS. The mean magnitude (modulus) of the displacement of the pupil with the change of the illumination conditions was 0.21 ± 0.11 mm. The effect of this pupillary shift was manifest for coma corneal aberrations for 5-mm pupils, but the two sets of aberrations calculated with the two pupil positions were not significantly different. Sixty-eight percent of the population had differences in coma smaller than 0.05 µm, and only 4% had differences larger than 0.1 µm. Pupil displacement was not large enough to significantly affect other higher-order Zernike modes. CONCLUSIONS. Estimated corneal aberrations changed slightly between photopic and mesopic illumination conditions given by corneal topography and Hartmann-Shack aberrometry. However, this systematic pupil shift, according to the published tolerances ranges, is enough to deteriorate the optical quality below the theoretically predicted diffraction limit of wavefront-guided corneal surgery.

A novel technique to demonstrate disturbed appetite profiles in haemodialysis patients

Background Malnutrition is common among dialysis patients and is associated with an adverse outcome. One cause of this is a persistent reduction in nutrient intake, suggesting an abnormality of appetite regulation. Methods We used a novel technique to describe the appetite profile in 46 haemodialysis (HD) patients and 40 healthy controls. The Electronic Appetite Rating System (EARS) employs a palmtop computer to collect hourly ratings of motivation to eat and mood. We collected data on hunger, desire to eat, fullness, and tiredness. HD subjects were monitored on the dialysis day and the interdialytic day. Controls were monitored for 1 or 2 days. Results Temporal profiles of motivation to eat for the controls were similar on both days. Temporal profiles of motivation to eat for the HD group were lower on the dialysis day. Mean HD scores were not significantly different from controls. Dietary records indicated that dialysis patients consumed less food than controls. Conclusions Our data indicate that the EARS can be used to monitor subjective appetite states continuously in a group of HD patients. A HD session reduces hunger and desire to eat. Patients feel more tired after dialysis. This does not correlate with their hunger score, but does correlate with their fullness rating. Nutrient intake is reduced, suggesting a resetting of appetite control for the HD group. The EARS may be useful for intervention studies.

Textures of optical flow for real-time anomaly detection in crowds

Automated visual surveillance of crowds is a rapidly growing area of research. In this paper we focus on motion representation for the purpose of abnormality detection in crowded scenes. We propose a novel visual representation called textures of optical flow. The proposed representation measures the uniformity of a flow field in order to detect anomalous objects such as bicycles, vehicles and skateboarders; and can be combined with spatial information to detect other forms of abnormality. We demonstrate that the proposed approach outperforms state-of-the-art anomaly detection algorithms on a large, publicly-available dataset.

Auditory spatial acuity approximates the resolving power of space-specific neurons

The relationship between neuronal acuity and behavioral performance was assessed in the barn owl (Tyto alba), a nocturnal raptor renowned for its ability to localize sounds and for the topographic representation of auditory space found in the midbrain. We measured discrimination of sound-source separation using a newly developed procedure involving the habituation and recovery of the pupillary dilation response. The smallest discriminable change of source location was found to be about two times finer in azimuth than in elevation. Recordings from neurons in its midbrain space map revealed that their spatial tuning, like the spatial discrimination behavior, was also better in azimuth than in elevation by a factor of about two. Because the PDR behavioral assay is mediated by the same circuitry whether discrimination is assessed in azimuth or in elevation, this difference in vertical and horizontal acuity is likely to reflect a true difference in sensory resolution, without additional confounding effects of differences in motor performance in the two dimensions. Our results, therefore, are consistent with the hypothesis that the acuity of the midbrain space map determines auditory spatial discrimination.

Dynamic texture reconstruction from sparse codes for unusual event detection in crowded scenes

Unusual event detection in crowded scenes remains challenging because of the diversity of events and noise. In this paper, we present a novel approach for unusual event detection via sparse reconstruction of dynamic textures over an overcomplete basis set, with the dynamic texture described by local binary patterns from three orthogonal planes (LBPTOP). The overcomplete basis set is learnt from the training data where only the normal items observed. In the detection process, given a new observation, we compute the sparse coefficients using the Dantzig Selector algorithm which was proposed in the literature of compressed sensing. Then the reconstruction errors are computed, based on which we detect the abnormal items. Our application can be used to detect both local and global abnormal events. We evaluate our algorithm on UCSD Abnormality Datasets for local anomaly detection, which is shown to outperform current state-of-the-art approaches, and we also get promising results for rapid escape detection using the PETS2009 dataset.