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Purpose. Recently devised tests have implemented forms of interocular suppression (e.g., binocular rivalry) to assess eyedominance. In an effort to combine the strengths of these tests, the authors introduce a new technique for quantifying the magnitude of interocular suppression by using an easily administered psychophysical test. Methods. Eighty-eight observers participated in the interocular suppression test, which involved dichoptic presentation of dynamic noise to one eye and a target stimulus to the other. Observers made a form-discrimination judgment once the target emerged from suppression. The authors reasoned that the dominanteye is less susceptible to interocular suppression and as a result, perception and thus, form discrimination would be faster when the target is presented to the dominanteye as opposed to the nondominant eye. Observers' sighting dominance, acuity, contrast sensitivity, and test–retest reliability were also assessed. Results. There were significant interocular differences in mean reaction times within and across observers. Of the observers, 68% and 32% observers were categorized as right eyedominant and left eyedominant, respectively, according to the test. Moreover, 38% of observers showed strong eyedominance. Observers' discrimination accuracy (98%) and test–retest reliability (r = 0.52–0.67) were high. Consistent with results in previous studies, statistical correlations were weak between the sighting dominance test, acuity scores, contrast sensitivity measures, and the interocular suppression test. Conclusions. This interocular suppression technique offers an efficient, reliable, quantitative method of evaluating eyedominance and may be useful in making decisions about differential refractive correction of the two eyes.
A push–pull training protocol is applied to reduce sensoryeyedominance in the foveal region. The training protocol consists of cueing the weak eye to force it to become dominant while the strong eye is suppressed when a pair of dichoptic orthogonal grating stimulus is subsequently presented to it (Ooi & He, 1999). We trained with four pairs of dichoptic
Sensoryeyedominance (SED) reflects an imbalance of interocular inhibition in the binocular network. Extending an earlier work (Ooi & He, 2001) that measured global SED within the central 6°, the current study measured SED locally at 17 locations within the central 8° of the binocular visual field. The eccentricities (radius) chosen for this, “binocular perimetry”, study were 0° (fovea),
A push-pull training protocol is applied to reduce sensoryeyedominance in the foveal region. The training protocol consists of cueing the weak eye to force it to become dominant while the strong eye is suppressed when a pair of dichoptic orthogonal grating stimulus is subsequently presented to it (Ooi & He, 1999). We trained with four pairs of dichoptic orthogonal gratings (0°/90°, 90°/0°, 45°/135° and 135°/45° at 3cpd) to affect the interocular inhibitory interaction tuned to the four trained orientations (0°, 45°, 90° and 135°). After a 10-day training session, we found a significant learning effect (reduced sensoryeyedominance) at the trained orientations as well as at two other untrained orientations (22.5° and 67.5°). This suggests that the four pairs of oriented training stimuli are sufficient to produce a learning effect at any other orientation. The nearly complete transfer of the learning effect across orientation is attributed to the fact that the trained and untrained orientations are close enough to fall in the same orientation tuning function of the early visual cortical neurons (?37.5°). Applying the same notion of transfer of learning within the same feature channel, we also found a large transfer effect to an untrained spatial frequency (6cpd), which is 1 octave higher than the trained spatial frequency (3cpd). Furthermore, we found that stereopsis is improved, as is the competitive ability between the two eyes, after the push-pull training. Our data analysis suggests that these improvements are correlated with the reduced sensoryeyedominance after the training, i.e., due to a more balanced interocular inhibition. We also found that the learning effect (reduced SED and stereo threshold) can be retained for more than a year after the termination of the push-pull training. PMID:21689673
Perceptual learning is an important means for the brain to maintain its agility in a dynamic environment. Top-down focal attention, which selects task-relevant stimuli against competing ones in the background, is known to control and select what is learned in adults. Still unknown, is whether the adult brain is able to learn highly visible information beyond the focus of top-down attention. If it is, we should be able to reveal a purely stimulus-driven perceptual learning occurring in functions that are largely determined by the early cortical level, where top-down attention modulation is weak. Such an automatic, stimulus-driven learning mechanism is commonly assumed to operate only in the juvenile brain. We performed perceptual training to reduce sensoryeyedominance (SED), a function that taps on the eye-of-origin information represented in the early visual cortex. Two retinal locations were simultaneously stimulated with suprathreshold, dichoptic orthogonal gratings. At each location, monocular cueing triggered perception of the grating images of the weak eye and suppression of the strong eye. Observers attended only to one location and performed orientation discrimination of the gratings seen by the weak eye, while ignoring the highly visible gratings at the second, unattended, location. We found SED was not only reduced at the attended location, but also at the unattended location. Furthermore, other untrained visual functions mediated by higher cortical levels improved. An automatic, stimulus-driven learning mechanism causes synaptic alterations in the early cortical level, with a far-reaching impact on the later cortical levels. PMID:21658403
IT is a well-known fact that while our vision is binocular, one eye (more often the right than the left) is in fact preferred or dominant in fixation and sighting. Much has been published on this subject, especially in its relation to handedness. We conjectured that if one eye is dominant in sighting, the other, that is, the non-dominanteye,
A recent paper examined eyedominance with the eyes in forward and eccentric gaze [Vision Res. 41 (2001) 1743]. When observers were looking to the left, the left eye tended to dominate and when they were looking to the right, the right eye tended to dominate. The authors attributed the switch in eyedominance to extra-retinal signals associated with horizontal
People perceive the material world around them with their five senses. Information from different sensory modalities is integrated in the brain to create a stable and meaningful experience of objects, including industrial products that accompany us in our everyday life. Some of the sensory systems play a more important role in product experience than others. Designing pleasurable products can enrich
We studied the role of eyedominance in non-rivalry conditions, testing dichoptic visual search and comparing performance with target presented to the dominant or non-dominanteye. Using red–green glasses, subjects viewed an array of green and red lines of uniform orientation, with a differently oriented target line present on half the trials. Performance was significantly better when the dominanteye
In a sample of 807 normal preschool children aged from 3 to 6, examined eyedominance was not associated with the declared eyedominance of their parents. Forty percent of the children showed left-eyedness. Eyedness was associated with handedness and not significantly related to age group or sex. A strong relationship between the answers of the two parents concerning eye
Georges Dellatolas; Florence Curt; Catherine Dargent-Paré; Maria De Agostini
While it is clear that one eye is visually dominant, the function of dominance, if any, is not fully understood. We looked for effects of eyedominance on visual feature search, the easy task of detecting an element that differs significantly in a single dimension from surrounding distractors. Thirteen subjects were tested, each with similar visual acuities in their two
Most people prefer to use their right eye for viewing. New evidence reveals that this dominance is much more plastic than that for one hand or foot: it changes from one eye to the other depending on angle of gaze. Remarkably, sighting dominance depends on the hand being directed towards the visual target.
We previously found a dominanteye perceptional advantage in feature search (Vision Research, 2006). We now ask if this advantage extends to difficult conjunction search, which requires focused attention and depends on different cortical hierarchy levels. We determined eyedominance by the Hole-in-the-Card test. Using red–green glasses, subjects viewed a briefly presented, backward-masked, array of red\\/green dotted squares and filled
The projection from the contralateral eyedominates the cat's visual cortex. Binocular neurones in any small region have their receptive fields more widely scattered over the ipsilateral retina than over the contralateral. Stereoscopic vision may depend on this difference in the two projections.
CT measurements of right and left occipital length and width were correlated with eyedominance for 14 men and 27 women. Female subjects demonstrated little relationship between eyedominance and occipital measurements. For male subjects, however, right eyedominance was significantly correlated with increased lengths and widths for both right and left hemispheres on CT slices W, SM, and SM
|Investigated Neuro-Linguistic Programming eye movement model's claim that specific eye movements are indicative of specific sensory components in thought. Agreement between students' (N=48) self-reports and trained observers' records support visual and auditory portions of model; do not support kinesthetic portion. Interrater agreement supports…
Fifty?four children with congenital hemiplegia (25 left and 29 right hemiplegics) were administered a battery of sensory and perceptual tests, the results of which were related to measures of motor asymmetry obtained from the same children. Asymmetries of visual acuity and eyedominance were largely independent of motor asymmetry. Asymmetries of stereognosis and finger identification, but not graphesthesia, were associated
Cheryl K. Hiscock; Merrill Hiscock; David Benjamins; Stephen Hillman
This study was designed to throw additional light on the problem of mixed eye-hand dominance in relation to reading disability. A group of elementary school children, 101 boys and 90 girls ranging in age from 6 to 11 years who rated above average in general ability, were administered tests of eye and hand dominance. Stanford achievement reading scores were available
|This study was based on the following assumptions: (1) functioning of the brain's left hemisphere, because of its logical, verbal mode, facilitates conservation reasoning; (2) functioning of the brain's right hemisphere, because of its nonverbal, spatial mode, inhibits conservation reasoning; (3) visual input from the left eye will reach the left…
Previous data suggested that vertical imbalances between the eyes produced by lateral head tilt are linked to ocular dominance, but no studies have heretofore objectively measured head tilt in addressing this relationship. Photographic measurements of the...
The paper reports on the development of the equipment for studies of the eyedominance and ocular stereoprevalence by using black-and-white and color stereostimuli. The stereostimuli are separated either by color-filter goggles or phase separating liquid-crystal-shutter goggles. The stability of the stereoprevalence is studied by artificial step-by-step deterioration of the retinal image quality, particularly in the dominanteye. The stimuli
Maris Ozolinsh; Karina Anisko; Gatis Ikaunieks; Gunta Krumina
Summary The purpose of the present study was to evaluate the relation between photographically assessed changes in eye redness and sensoryeye irritation in 17 patients suffering from hayfever, provoked by increasing doses of birch pollen in the eye. Pre- and post-exposure diapositives were compared in a randomized and double blind design by a panel of five members. By evaluating
Søren K. Kjærgaard; Ole F. Pedersen; Ebbe Taudorf; Lars Molhavel
We studied eyedominance in visual cortex and lateral geniculate nucleus (LGN) using functional magnetic resonance imaging (fMRI) at a very high magnetic field (4 tesla). Eight normal volunteers were studied with fMRI at 4 tesla during alternating monocular visual stimulation. The acquisition was repeated twice in 4 subjects to confirm reproducibility. In addition, magnetic resonance signal intensities during three
Atsushi Miki; Grant T. Liu; Sarah A. Englander; Theo G. M. van Erp; Gabrielle R. Bonhomme; David O. Aleman; Chia-Shang J. Liu; John C. Haselgrove
|This longitudinal study was a replication of two disparate studies, one of dominance and one of control, which had as subjects 277 seventh- and eighth-grade pupils remaining from an original dominance study of over 500. Eyedominance was determined through hole-in-paper and V-scope; eye control at near and far point, through the telebinocular;…
There have been many attempts to define eyedominance in normal subjects, but limited consensus exists, and relevant physiological data is scarce. In this study, we consider two different behavioral methods for assignment of eyedominance, and how well they predict fMRI signals evoked by monocular stimulation. Sighting eyedominance was assessed with two standard tests, the Porta Test, and
The three existing dominant gain-of-function Drop alleles, Dr1, DrMioand DrWe, previously assumed to define a single locus, severely disrupt eye development. Genetic analysis of ethylmethanesulphonate (EMS) and irradiation-induced revertants revealed that the Drop mutations define two loci: the Drop locus, which is defined by the Dr1 and DrMio mutants, and a separate locus defined by the DrWe mutation, which has
Purpose: To develop a functional MRI method for producing eyedominance histograms in humans at 1.5 Tesla (T). Methods: In the first set of experiments, 8 normal persons were tested. The eyedominance of each voxel within the person's visually activated primary visual cortex was determined with Student t statistics during a left eye versus right eye contrast. Eyedominance
Grant T. Liu; Atsushi Miki; Zachariah Goldsmith; Theo G. M. van Erp; Ellie Francis; Graham E. Quinn; Edward J. Modestino; Gabrielle R. Bonhomme; John C. Haselgrove
Although monocular recognition scores for targets presented immediately after an eye movement do not differ, the two eyes\\u000a show marked recognition asymmetries when both eyes are receiving inputs but a specific target is only presented to one. In\\u000a general, the right eye performs better than the left, although there are interactions with sighting dominance and the direction\\u000a of eye movement.
Summary Observations in primates and patients with unilateral spatial neglect have suggested that patching of the eye ipsilateral to the injury and contralateral to the neg- lected space can sometimes improve attention to the neglected space. Investigators have generally attributed the effects of monocular eye patching to activation of subcortical centers that interact with cortical attentional systems. Eye patching is
Two experiments were performed to re-evaluate the sensory irritating properties of 2-ethylhexanol in relation to dose and time and to examine the usability of electromyographic eye blink recordings as indicator of sensory irritation. Mean exposure levels of 1.5, 10 and 20ppm were realized in experimental models simulating either constant or variable 4h exposure. Each study was carried out with two
Ernst Kiesswetter; Christoph van Thriel; Michael Schäper; Meinolf Blaszkewicz; Andreas Seeber
Objective: To examine the relative effect of hand dominance on the median and ulnar sensory evoked responses and grip strength in active workers.Design: A cross-sectional or survey design.Setting: Workers from 4 different sites underwent on-site testing of the median and ulnar sensory nerves in both hands (antidromic stimulation, 14cm), and testing of bilateral grip strength.Patients: 224 workers, asymptomatic of hand,
We have isolated a dominant mutation, pugilist Dominant (pug D ), that causes variegated reductions in pteridine and ommochrome pigmentation of the Drosophila eye. The effect of pug D on pteridine pigmentation is most dramatic: the only remaining pigment consists of a thin ring of pigment around the periphery of the eye with a few scattered spots in the center.
Background How and why animals lose eyesight during adaptation to the dark and food-limited cave environment has puzzled biologists since the time of Darwin. More recently, several different adaptive hypotheses have been proposed to explain eye degeneration based on studies in the teleost Astyanax mexicanus, which consists of blind cave-dwelling (cavefish) and sighted surface-dwelling (surface fish) forms. One of these hypotheses is that eye regression is the result of indirect selection for constructive characters that are negatively linked to eye development through the pleiotropic effects of Sonic Hedgehog (SHH) signaling. However, subsequent genetic analyses suggested that other mechanisms also contribute to eye regression in Astyanax cavefish. Here, we introduce a new approach to this problem by investigating the phenotypic and genetic relationships between a suite of non-visual constructive traits and eye regression. Results Using quantitative genetic analysis of crosses between surface fish, the Pachón cavefish population and their hybrid progeny, we show that the adaptive vibration attraction behavior (VAB) and its sensory receptors, superficial neuromasts (SN) specifically found within the cavefish eye orbit (EO), are genetically correlated with reduced eye size. The quantitative trait loci (QTL) for these three traits form two clusters of congruent or overlapping QTL on Astyanax linkage groups (LG) 2 and 17, but not at the shh locus on LG 13. Ablation of EO SN in cavefish demonstrated a major role for these sensory receptors in VAB expression. Furthermore, experimental induction of eye regression in surface fish via shh overexpression showed that the absence of eyes was insufficient to promote the appearance of VAB or EO SN. Conclusions We conclude that natural selection for the enhancement of VAB and EO SN indirectly promotes eye regression in the Pachón cavefish population through an antagonistic relationship involving genetic linkage or pleiotropy among the genetic factors underlying these traits. This study demonstrates a trade-off between the evolution of a non-visual sensory system and eye regression during the adaptive evolution of Astyanax to the cave environment.
Evidence suggests that there are systematic phenomenal differences between the views displayed in consciousness from the dominant and the nondomi- nant eyes. We suggest that these differences provide a basis for utrocular discrimination.
In this paper, we focus on facial displays, eye gaze and head tilts to express social dominance. In particular, we are interested in the interaction of different non-verbal cues. We present a study which systematically varies eye gaze and head tilts for five basic emotions and a neutral state using our own graphics and animation engine. The resulting images are
Plastic changes in intrahemisphere neuronal connections of the eye-dominance columns of cortical fields 17 and 18 were studied\\u000a in monocularly deprived cats. The methodology consisted of microintophoretic administration of horseradish peroxidase into\\u000a cortical columns and three-dimensional reconstruction of the areas of retrograde labeled cells. The eyedominance of columns\\u000a was established, as were their coordinates in the projection of the
S. V. Alekseenko; S. N. Toporova; P. Yu. Shkorbatova
L'A. approche le phénomèna de la latéralisation à travers un modèle théorique combinant dominance cérébrale et conformité culturelle. Le taux D'incidence de gaucherie dans une société paiticulière résulterait de l'interaction du potentiel génétique de latéralisation (dominance hémisphérique) et des pressions culturelles vers la conformité. Une étude interculturelle de ces variables, effectuée sur des sujets Temne (Sierra Leone) et Arunta (Australie),
There have been many attempts to define eyedominance in normal subjects, but limited consensus exists, and relevant physiological data is scarce. In this study, we consider two different behavioral methods for assignment of eyedominance, and how well they predict fMRI signals evoked by monocular stimulation. Sighting eyedominance was assessed with two standard tests, the Porta Test, and a ‘hole in hand’ variation of the Miles Test. Acuity dominance was tested with a standard eye chart and with a computerized test of grating acuity. We found limited agreement between the sighting and acuity methods for assigning dominance in our individual subjects. We then compared the fMRI response generated by dominanteye stimulation to that generated by non-dominanteye, according to both methods, in 7 normal subjects. The stimulus consisted of a high contrast hemifield stimulus alternating with no stimulus in a blocked paradigm. In separate scans, we used standard techniques to label the borders of visual areas V1, V2, V3, VP, V4, V3A, and MT. These regions of interest (ROIs) were used to analyze each visual area separately. We found that percent change in fMRI BOLD signal was stronger for the dominanteye as defined by the acuity method, and this effect was significant for areas located in the ventral occipital territory (V1v, V2v, VP, V4). In contrast, assigning dominance based on sighting produced no significant interocular BOLD differences. We conclude that interocular BOLD differences in normal subjects exist, and may be predicted by acuity measures.
|This study attempted to gather baseline data on a randomly selected population of 353 kindergarten and first-grade children for consistency of response in hand dominance measures and eyedominance measures and for comparison by sex, race, maturity and socioeconomic status. (Author/SB)|
We have investigated expression of the homeobox gene Prox 1 during eye degeneration and sensory organ compensation in cavefish embryos. The teleost Astyanax mexicanus consists of sighted surface-dwelling forms (surface fish) and several populations of blind cave-dwelling forms (cavefish),\\u000a which have evolved independently. Eye formation is initiated during cavefish development, but the lens vesicle undergoes apoptosis,\\u000a and the eye subsequently
William R. Jeffery; Allen G. Strickler; Stephanie Guiney; Deidre G. Heyser; Stanislav I. Tomarev
Sighting dominance (the behavioural preference for one eye over the other under monocular viewing conditions) has traditionally been thought of as a robust individual trait. However, Khan and Crawford (2001) have shown that, under certain viewing conditions, eye preference reverses as a function of horizontal gaze angle. Remarkably, the reversal of sighting from one eye to the other depends on which hand is used to reach out and grasp the target. Their procedure provides an ideal way to measure the strength of monocular preference for sighting, which may be related to other indicators of hemispheric specialisation for speech, language and motor function. Therefore, we hypothesised that individuals with consistent side preferences (e.g., right hand, right eye) should have more robust sighting dominance than those with crossed lateral preferences. To test this idea, we compared strength of eyedominance in individuals who are consistently right or left sided for hand and foot preference with those who are not. We also modified their procedure in order to minimise a potential image size confound, suggested by Banks et al. (2004) as an explanation of Khan and Crawford's results. We found that the sighting dominance switch occurred at similar eccentricities when we controlled for effects of hand occlusion and target size differences. We also found that sighting dominance thresholds change predictably with the hand used. However, we found no evidence for relationships between strength of hand preference as assessed by questionnaire or by pegboard performance and strength of sighting dominance. Similarly, participants with consistent hand and foot preferences did not show stronger eye preference as assessed using the Khan and Crawford procedure. These data are discussed in terms of indirect relationships between sighting dominance, hand preference and cerebral specialisation for language and motor control. PMID:23357202
I quantified the costs of switching from a familiar to an unfamiliar flock for captive dark-eyed juncos (Junco h. hyemalis) by measuring several physiological and behavioral variables before and after flock switching. Birds that were initially dominant dropped in status in unfamiliar flocks, and experienced increased metabolic rates, while subordinate birds appeared to undergo less physiological change when switching flocks.
Objectives: Our study determined whether depth perception defects and hand-eyedominance affect an individual's ability to perform laparoscopic skills. Methods: The study cohort comprised 104 third-year medical students from LSU School of Medicine who completed a questionnaire including information on handedness and were tested for eyedominance and depth perception by using standardized methods. Training sessions involved an initial recorded performance, a 20-minute practice session, followed by a final recorded performance. Recorded sessions were randomized and rated by using a visual analog scale (maximal possible score = 16) based on overall performance (OPS) and depth perception (DPS). A general linear model was used to correlate depth perception defects and hand-eyedominance with assessment scores for OPS and DPS. Results: Students with depth perception defects scored significantly lower on their initial performance than did those with normal depth perception (OPS, 4.80 vs. 7.16, P=0.0008; DPS, 5.25 vs. 6.93, P=0.0195). After training, the depth perception defect group continued to have lower scores compared with the normal depth perception group. However, the 2 groups showed similar increases in pre- to posttraining performance scores (OPS, 3.84 vs. 3.18, P=0.0732). Hand-eyedominance did not significantly affect scores. Conclusions: Depth perception defects appear to compromise an individual's ability to perform basic laparoscopic skills. Individuals with defects can improve their skills by a proportion comparable to that of people with uncompromised depth perception. Differences in hand-eyedominance do not correlate with performance differences in basic laparoscopic skills. Although further research is necessary, the findings indicate that training can be tailored for individuals with depth perception defects to improve laparoscopic performance.
Suleman, Rabiya; Yang, Tong; Paige, John; Chauvin, Sheila; Alleyn, Jaime; Brewer, Martha; Johnson, Stephen I.
Neural responses are variable, yet motor performance can be quite precise. To ask how neural signal and noise are processed in the brain during sensory–motor behavior, we have evaluated the trial-by-trial variation of Purkinje cell (PC) activity in the floccular complex of the cerebellum, an intermediate stage in the neural circuit for smooth-pursuit eye movements. We find strong correlations between small trial-by-trial variations in the simple spike activity of individual PCs and the eye movements at the initiation of pursuit. The correlation is lower but still present during steady-state pursuit. Recordings from a few pairs of PCs verified the predictions of a model of the PC population, that there is a transition from highly covariant PC activity during movement initiation to more independent activity later on. Application to the data of a theoretical and computational analysis suggests that variation in pursuit initiation arises mostly from variation in visual motion signals that provide common inputs to the PC population. Variation in eye movement during steady-state pursuit can be attributed primarily to signal-dependent motor noise that arises downstream from PCs.
We investigated the effects of refractive correction and refractive defocus on the assessment of sensory ocular dominance. In 25 healthy subjects (4 males and 21 females) aged between 20 and 31 years, a quantitative measurement of sensory ocular dominance was performed with refractive correction and the addition of a positive lens on the dominanteye. Sensory ocular dominance was measured with a chart using binocular rivalry targets. The reversal point changed after the addition of a +1.00 D lens on the dominanteye in all subjects. However, sighting ocular dominance and stereopsis did not change after the addition of a positive lens on the dominanteye ( P > 0:05, Wilcoxon test). These results suggest that refractive correction affects sensory ocular dominance, indicating the possible development of a new type of occlusion for amblyopia in the future.
Schizophrenia is referred to as cerebral lateralisation abnormality. In this study the possible relationships among handedness, eyedominance, and crossed and non-congruent hand–eyedominance in patients with schizophrenia are investigated. A total of 88 patients with schizophrenia and 118 controls were included in the study. The patient group included 60 men and 28 women who ranged in age from 17
Characteristics of saccades and presaccadic slow potentials were studied in 36 right-handed men with right (the RE group)\\u000a and left (the LE group) eyedominance. Three light-emitting diodes located in the center of the visual field (the central\\u000a fixation stimulus, CFS) and 10 deg to the left and to the right of the center (peripheral stimuli, PSs) were used for
Introduction: Cerebral palsy (CP) is a term used to describe a spectrum of deficits of muscle tone and posture resulting from damage to the developing nervous system. Though considered a motor disorder, CP can be associated with disorders of the sensory visual pathway. This paper, the final in a series of three articles, will present frequency, diagnosis, and management of the visual and binocular vision deficits associated with CP. Topics for discussion will include the prevalence and etiology of decreased acuity, the effect of CP on sensory and motor fusion, and the response to treatment for these sensory deficits. Methods: A retrospective chart review of all cases of cerebral palsy referred to the St. Louis Children's Hospital Eye Center was done. Detailed data on the sensory and motor deficits documented in these children was collected. Also recorded was the management strategy and response to treatment. Results: Of the 131 cases reviewed (mean age 5.2 years at presentation), 46% had decreased vision in at least one eye due to amblyopia (24%), optic nerve abnormality (16%), cortical visual impairment (14%), or a combination. Forty-nine (37%) had significant refractive error. Sixty-four percent of those with significant refractive error responded to spectacle correction. Forty-three percent of those with amblyopia responded to conventional therapies. Of the nonstrabismic patients, 89% demonstrated sensory fusion, 90% had stereopsis, and 91% had motor fusion. No patient lacking fusion or stereopsis prior to strabismus surgery gained these abilities with realignment of the eyes. Conclusion: While children with CP are capable of age-appropriate acuity and binocular vision, they are at increased risk for sensory visual deficits. These deficits are not the direct result of CP itself, but either share a common underlying cause, or occur as sequelae to the strabismus that is prevalent in CP. Most importantly, some sensory deficits may respond to standard treatment methods. PMID:21149136
This study compared the performance of two sensory description methods, Temporal Dominance of Sensations (TDS) and key-attribute sensory profiling, in order to assess the sensory attributes of fish sticks (two different commercial brands) cooked by three different procedures (deep frying, conventional oven and microwaving).The TDS method has scarcely ever been applied to solid food and battered fish sticks are a
We have isolated a dominant mutation, pugilistDominant (pugD), that causes variegated reductions in pteridine and ommochrome pigmentation of the Drosophila eye. The effect of pugD on pteridine pigmentation is most dramatic: the only remaining pigment consists of a thin ring of pigment around the periphery of the eye with a few scattered spots in the center. The pugD mutation disrupts a gene that encodes a Drosophila homolog of the trifunctional enzyme methylenetetrahydrofolate dehydrogenase (MTHFD; E.C.126.96.36.199, E.C.3.5. 4.9, E.C.188.8.131.52). This enzyme produces a cofactor that is utilized in purine biosynthesis. Because pteridines are derived from GTP, the pigment defect may result from an impairment in the production of purines. The mutant allele consists of a portion of the MTHFD coding region fused to approximately 1 kb of highly repetitive DNA. Transcription and translation of both parts are required for the phenotype. The repetitive DNA consists of approximately 140 nearly perfect repeats of the sequence AGAGAGA, a significant component of centric heterochromatin. The unusual nature of the protein produced by this gene may be responsible for its dominance. The repetitive DNA may also account for the variegated aspect of the phenotype. It may promote occasional association of the pugD locus with centric heterochromatin, accompanied by inactivation of pugD, in a manner similar to the proposed mode of action for brownDominant.
The sensory weighting model is a general model of sensory integration that consists of three processing layers. First, each sensor provides the central nervous system (CNS) with information regarding a specific physical variable. Due to sensor dynamics, this measure is only reliable for the frequency range over which the sensor is accurate. Therefore, we hypothesize that the CNS improves on the reliability of the individual sensor outside this frequency range by using information from other sensors, a process referred to as "frequency completion." Frequency completion uses internal models of sensory dynamics. This "improved" sensory signal is designated as the "sensory estimate" of the physical variable. Second, before being combined, information with different physical meanings is first transformed into a common representation; sensory estimates are converted to intermediate estimates. This conversion uses internal models of body dynamics and physical relationships. Third, several sensory systems may provide information about the same physical variable (e.g., semicircular canals and vision both measure self-rotation). Therefore, we hypothesize that the "central estimate" of a physical variable is computed as a weighted sum of all available intermediate estimates of this physical variable, a process referred to as "multicue weighted averaging." The resulting central estimate is fed back to the first two layers. The sensory weighting model is applied to three-dimensional (3D) visual-vestibular interactions and their associated eye movements and perceptual responses. The model inputs are 3D angular and translational stimuli. The sensory inputs are the 3D sensory signals coming from the semicircular canals, otolith organs, and the visual system. The angular and translational components of visual movement are assumed to be available as separate stimuli measured by the visual system using retinal slip and image deformation. In addition, both tonic ("regular") and phasic ("irregular") otolithic afferents are implemented. Whereas neither tonic nor phasic otolithic afferents distinguish gravity from linear acceleration, the model uses tonic afferents to estimate gravity and phasic afferents to estimate linear acceleration. The model outputs are the internal estimates of physical motion variables and 3D slow-phase eye movements. The model also includes a smooth pursuit module. The model matches eye responses and perceptual effects measured during various motion paradigms in darkness (e.g., centered and eccentric yaw rotation about an earth-vertical axis, yaw rotation about an earth-horizontal axis) and with visual cues (e.g., stabilized visual stimulation or optokinetic stimulation). PMID:12068787
Inter- and intra-sensory modality matching by 8-year-old children diagnosed as having hand-eye co-ordination problems (HECP)\\u000a and by a control group of children without such problems were tested using a target-location and pointing task. The task required\\u000a the children to locate target pins visually (seen target), with the hand (felt target) or in combination (felt and seen target),\\u000a while pointing to
H. Sigmundsson; R. P. Ingvaldsen; H. T. A. Whiting
Objective: To replicate the left minus right (L?R) hemisphere EEG power shifts coupled to rapid eye movement (REM) and non-rapid eye movement (NREM) sleep observed in 1972 by Goldstein (Physiol Behav (1972) 811), and to characterize the L?R EEG power spectra for total EEG, delta, theta, alpha and beta bands.Background: Ultradian alternating cerebral hemispheric dominance rhythms are observed using EEG
David S Shannahoff-Khalsa; J. Christian Gillin; F. Eugene Yates; Arlene Schlosser; Eugene M Zawadzki
|This study explored general relationships between figural creativity, as measured by the Torrance Tests of Creative Thinking, and cerebral dominance, as identified by the conjugate lateral eye movement (CLEM) interview procedure. Subjects were 175 adults. Results indicated no significant differences in figural creativity due to brain dominance…
Perceptual learning is an important means for the brain to maintain its agility in a dynamic environment. Top-down focal attention, which selects task-relevant stimuli against competing ones in the background, is known to control and select what is learned in adults. Still unknown, is whether the adult brain is able to learn highly visible information beyond the focus of top-down
Data from studies of interhemisphere connections in fields 17 and 18 of cats reared in conditions of impaired binocular vision\\u000a (monocular deprivation, uni- and bilateral strabismus) are presented. Monosynaptic connections between neurons were studied\\u000a by microiontophoretic application of horseradish peroxidase into cortical eyedominance columns and the distributions of retrograde\\u000a labeled callosal cells were analyzed. Spatial asymmetry and eye-specific interhemisphere
S. V. Alekseenko; S. N. Toporova; P. Yu. Shkorbatova
Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) is an autosomal-dominant neurodegenerative disorder characterized by widespread fasciculations, proximal-predominant muscle weakness, and atrophy followed by distal sensory involvement. To date, large families affected by HMSN-P have been reported from two different regions in Japan. Linkage and haplotype analyses of two previously reported families and two new families with the use of high-density SNP arrays further defined the minimum candidate region of 3.3 Mb in chromosomal region 3q12. Exome sequencing showed an identical c.854C>T (p.Pro285Leu) mutation in the TRK-fused gene (TFG) in the four families. Detailed haplotype analysis suggested two independent origins of the mutation. Pathological studies of an autopsied patient revealed TFG- and ubiquitin-immunopositive cytoplasmic inclusions in the spinal and cortical motor neurons. Fragmentation of the Golgi apparatus, a frequent finding in amyotrophic lateral sclerosis, was also observed in the motor neurons with inclusion bodies. Moreover, TAR DNA-binding protein 43 kDa (TDP-43)-positive cytoplasmic inclusions were also demonstrated. In cultured cells expressing mutant TFG, cytoplasmic aggregation of TDP-43 was demonstrated. These findings indicate that formation of TFG-containing cytoplasmic inclusions and concomitant mislocalization of TDP-43 underlie motor neuron degeneration in HMSN-P. Pathological overlap of proteinopathies involving TFG and TDP-43 highlights a new pathway leading to motor neuron degeneration.
Almost all individuals exhibit sensoryeyedominance, one neural basis of which is unequal interocular inhibition. Sensoryeyedominance can impair binocular functions that depend on both excitatory and inhibitory mechanisms. We developed a 'push-pull' perceptual learning protocol that simultaneously affects the excitatory and inhibitory networks to reduce sensoryeyedominance and improve stereopsis in adults with otherwise normal vision. The push-pull protocol provides a promising clinical paradigm for treating the extreme sensoryeyedominance in amblyopia ('lazy eye'). The prevailing standard of care does not directly treat sensoryeyedominance; instead, selected excitatory functions in the amblyopic eye are stimulated while the strong eye is patched, on the assumption that recovery of the weak eye's excitatory functions rebalances the eyes. Patching the strong eye does not directly address interocular inhibition; in contrast, the push-pull protocol by design excites the weak eye, while completely inhibiting the strong eye's perception to recalibrate the interocular balance of excitatory and inhibitory interactions. Here, we show that three adult amblyopes who trained on the push-pull protocol gained longstanding improvements in interocular balance and stereopsis. Our findings provide a proof-of-concept and evidence that push-pull learning leads to long-term plasticity. PMID:23618663
Ooi, Teng Leng; Su, Yong R; Natale, Danielle M; He, Zijiang J
The visual system is characterized by precise retinotopic mapping of each eye, together with exquisitely matched binocular projections. In many species, the inputs that represent the eyes are segregated into ocular dominance columns in primary visual cortex (V1), whereas in rodents, this does not occur. Ten-m3, a member of the Ten-m/Odz/Teneurin family, regulates axonal guidance in the retinogeniculate pathway. Significantly, ipsilateral projections are expanded in the dorsal lateral geniculate nucleus and are not aligned with contralateral projections in Ten-m3 knockout (KO) mice. Here, we demonstrate the impact of altered retinogeniculate mapping on the organization and function of V1. Transneuronal tracing and c-fos immunohistochemistry demonstrate that the subcortical expansion of ipsilateral input is conveyed to V1 in Ten-m3 KOs: Ipsilateral inputs are widely distributed across V1 and are interdigitated with contralateral inputs into eyedominance domains. Segregation is confirmed by optical imaging of intrinsic signals. Single-unit recording shows ipsilateral, and contralateral inputs are mismatched at the level of single V1 neurons, and binocular stimulation leads to functional suppression of these cells. These findings indicate that the medial expansion of the binocular zone together with an interocular mismatch is sufficient to induce novel structural features, such as eyedominance domains in rodent visual cortex. PMID:22499796
THE compound eye of the adult fruitfly, Drosophila melanogaster, comprises about 800 identical ommatidia, or unit eyes, each containing 20 distinct cells1,2. We have used histological and immunocytochemical methods to study the development of the compound eye in Ellipse (Elp) mutants. In Elp\\/Elp, most ommatidia do not initiate differentiation. We present genetic evidence that Elp alleles are mutations of the
Approaching or looming sounds (L-sounds) have been shown to selectively increase visual cortex excitability [Romei, V., Murray, M. M., Cappe, C., & Thut, G. Preperceptual and stimulus-selective enhancement of low-level human visual cortex excitability by sounds. Current Biology, 19, 1799-1805, 2009]. These cross-modal effects start at an early, preperceptual stage of sound processing and persist with increasing sound duration. Here, we identified individual factors contributing to cross-modal effects on visual cortex excitability and studied the persistence of effects after sound offset. To this end, we probed the impact of different L-sound velocities on phosphene perception postsound as a function of individual auditory versus visual preference/dominance using single-pulse TMS over the occipital pole. We found that the boosting of phosphene perception by L-sounds continued for several tens of milliseconds after the end of the L-sound and was temporally sensitive to different L-sound profiles (velocities). In addition, we found that this depended on an individual's preferred sensory modality (auditory vs. visual) as determined through a divided attention task (attentional preference), but not on their simple threshold detection level per sensory modality. Whereas individuals with "visual preference" showed enhanced phosphene perception irrespective of L-sound velocity, those with "auditory preference" showed differential peaks in phosphene perception whose delays after sound-offset followed the different L-sound velocity profiles. These novel findings suggest that looming signals modulate visual cortex excitability beyond sound duration possibly to support prompt identification and reaction to potentially dangerous approaching objects. The observed interindividual differences favor the idea that unlike early effects this late L-sound impact on visual cortex excitability is influenced by cross-modal attentional mechanisms rather than low-level sensory processes. PMID:23384192
Romei, Vincenzo; Murray, Micah M; Cappe, Céline; Thut, Gregor
In this paper we realistically model a two-eye visual environment and study its effect on single cell synaptic modification. In particular, we study the effect of image misalignment on receptive field formation after eye opening. We show that binocular mi...
Hereditary motor and sensory neuropathy with proximal dominancy (HMSN-P) is an adult-onset peripheral neurodegenerative disorder which has been reported only in the Okinawa Islands, Japan. The disease locus of "Okinawa-type" HMSN-P has been previously mapped to 3q13.1, with all affected individuals sharing an identical haplotype around the locus, suggesting that the undiscovered causative mutation in HMSN-P originated from a single founder. We have newly found two large families from the western part of Japan within which multiple members developed symptoms similar to those exhibited by HMSN-P patients from Okinawa, with no record of affinal connection between the islands. Using these pedigrees with "Kansai-type" HMSN-P, we carried out a linkage study utilizing eight microsatellite markers and identified a candidate region on 3q13.1 cosegregating with the disease (maximum two-point LOD score of 8.44 at theta=0.0) overlapping with the Okinawa-type HMSN-P locus. However, the disease haplotype shared among all affected members in these families was different from that in the Okinawa kindred, suggesting allelic heterogeneity. Such allelic variation should aid in the identification of the disease-causative gene. Moreover, the allelic heterogeneity of HMSN-P in the Japanese population suggests that HMSN-P may be more common across other ethnic groups, but classified into other disease categories. PMID:17906970
Pieces of hairy skin tissue of fetal rat were transplanted into the anterior eye chamber of adult rats. The ability of autonomic and sensory nerve fibers from the host iris to innervate the grafted skin tissue was immunohistochemically and enzyme-histochemically examined using antisera against tyrosine hydroxylase (TH), substance P (SP), calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP), and
We investigated the influence of eyedominance scaled by 6 tests on the parameters (N80, P100 latency and N80–P100 amplitude) of the white-black-, green-black-, red-black-and blue-black-pattern visual evoked potentials (PVEPs) of 40 healthy subjects (20 males and 20 females) with normal visual acuity. The P100 latency of the white-black PVEPs was, for both sexes, shorter (P = 0.001) in the
Many dyslexic children are unable accurately to control the movements of their eyes even when they are not trying to read. This immaturity helps to explain their visual confusions. It may result from failure to develop dependable associations between retinal and ocular motor signals these are essential to fix the true, as opposed to retinotopic, locations of objects in the
... increased pressure inside the eye. Untreated glaucoma can cause blindness. Pre-senile cataracts Clouding of the eye lens before age 60. Cataracts are common in older people who do not have Marfan ... do not usually cause vision problems, but they can help doctors decide ...
Binocularity is a fundamental property of primate vision. Ocular dominance describes the perceptual weight given to the inputs from the two eyes in their binocular combination. There is a distribution of sensorydominance within the normal binocular population with most subjects having balanced inputs while some are dominated by the left eye and some by the right eye. Using short-term monocular deprivation, the sensorydominance can be modulated as, under these conditions, the patched eye's contribution is strengthened. We address two questions: Is this strengthening a general effect such that it is seen for different types of sensory processing? And is the strengthening specific to pattern deprivation, or does it also occur for light deprivation? Our results show that the strengthening effect is a general finding involving a number of sensory functions, and it occurs as a result of both pattern and light deprivation. PMID:23599416
Inter- and intra-sensory modality matching by 8-year-old children diagnosed as having hand-eye co-ordination problems (HECP) and by a control group of children without such problems were tested using a target-location and pointing task. The task required the children to locate target pins visually (seen target), with the hand (felt target) or in combination (felt and seen target), while pointing to the located target was always carried out without vision. The most striking finding, for both the control and the HECP children, was the superiority of performance when the target had to be located visually. When combined scores for both hands were analysed, the HECP children showed inferior performance to the control children in both inter- and intra-modal matching. Analyses of the scores achieved with the preferred and non-preferred hand separately, however, demonstrated that the differences between the HECP and the control children could, in the main, be attributed to lowered performances when the non-preferred hand was used for pointing to the target. When pointing with the preferred hand, the only significant difference between the groups was when the target was visually located, the control children showing superior performance. Pointing with the non-preferred hand gave rise to significant differences, in favour of the control children, when the target was located visually, with the hand or in combination. These findings suggest that earlier studies, using only the preferred hand or a combination of the scores of both hands, might need to be qualified. Putative neurological disorders in the HECP children are invoked to account for the poor performance with the non-preferred hand. PMID:9187285
Like many modern and fossil arthropods, eurypterids had compound eyes and other sensory devices. Many eurypterids display small, bean-shaped eyes which are oriented for side viewing. The large bulbous eyes of Pterygotus are located on the edge of the head and were probably useful for looking both laterally and vertically.
The cells comprising the frontal eye of a 12.5 day amphioxus larva are described based on 3D reconstructions from serial electron micrographs, along with the fibre tracts and more caudal groupings of cells in the nerve cord to which the frontal eye appears to be linked. The frontal eye consists of a pigment cup, two transverse rows of receptor cells,
The hereditary ataxias represent a clinically and genetically heterogeneous group of neurodegenerative disorders. Various classification schemes based on clinical criteria are being replaced as molecular characterization of the ataxias proceeds; so far, seven distinct autosomal dominant hereditary ataxias have been genetically mapped in the human genome. We report linkage to chromosome 16q22.1 for one of these genes (SCA4) in a five-generation family with an autosomal dominant, late-onset spinocerebellar ataxia; the gene is tightly linked to the microsatellite marker D16S397 (LOD score = 5.93 at theta = .00). In addition, we present clinical and electrophysiological data regarding the distinct and previously unreported phenotype consisting of ataxia with the invariant presence of a prominent axonal sensory neuropathy.
Flanigan, K.; Gardner, K.; Alderson, K.; Galster, B.; Otterud, B.; Leppert, M. F.; Kaplan, C.; Ptacek, L. J.
Vibration attraction behavior (VAB) is the swimming of fish toward an oscillating object, a behavior that is likely adaptive because it increases foraging efficiency in darkness. VAB is seen in a small proportion of Astyanax surface-dwelling populations (surface fish) but is pronounced in cave-dwelling populations (cavefish). In a recent study, we identified two quantitative trait loci for VAB on Astyanax linkage groups 2 and 17. We also demonstrated that a small population of superficial neuromast sensors located within the eye orbit (EO SN) facilitate VAB, and two quantitative trait loci (QTL) were identified for EO SN that were congruent with those for VAB. Finally, we showed that both VAB and EO SN are negatively correlated with eye size, and that two (of several) QTL for eye size overlap VAB and EO SN QTLs. From these results, we concluded that the adaptive evolution of VAB and EO SN has contributed to the indirect loss of eyes in cavefish, either as a result of pleiotropy or tight physical linkage of the mutations underlying these traits. In a subsequent commentary, Borowsky argues that there is poor experimental support for our conclusions. Specifically, Borowsky states that: (1) linkage groups (LGs) 2 and 17 harbor QTL for many traits and, therefore, no evidence exists for an exclusive interaction among the overlapping VAB, EO SN and eye size QTL; (2) some of the QTL we identified are too broad (>20 cM) to support the hypothesis of correlated evolution due to pleiotropy or hitchhiking; and (3) VAB is unnecessary to explain the indirect evolution of eye-loss since the negative polarity of numerous eye QTL is consistent with direct selection against eyes. Borowsky further argues that (4) it is difficult to envision an evolutionary scenario whereby VAB and EO SN drive eye loss, since the eyes must first be reduced in order to increase the number of EO SN and, therefore, VAB. In this response, we explain why the evidence of one trait influencing eye reduction is stronger for VAB than other traits, and provide further support for a scenario whereby elaboration of VAB in surface fish may precede complete eye-loss. PMID:23844745
Yoshizawa, Masato; O'Quin, Kelly E; Jeffery, William R
|A study investigated the effectiveness with two individuals with severe mental retardation of Odyssey Now (ON), a multi-sensory program designed for use with people with mental retardation. Increases in interaction and engagement were observed during the ON sessions. Both individuals interacted more with their environment during ON sessions.…
Infusion of prostaglandin (PG) D2 into the lateral ventricle of the brain induced an increase in the amount of non-rapid eye move- ment sleep in wild-type (WT) mice but not in mice deficient in the PGD receptor (DP). Immunofluorescence staining of WT mouse brain revealed that DP immunoreactivity was dominantly localized in the leptomeninges (LM) of the basal forebrain but
Based on the available literature on activation of brain structures by fear- and anger-inducing stimuli, on the effects of electrical and chemical stimulation and lesions of candidate structures, and on connectional data, we propose that both the fear and power-dominance drives are represented in four distinct locations: the medial hypothalamus, lateral/dorsolateral periaqueductal gray, midline thalamic nuclei, and medial prefrontal cortex. The hypothalamic fear representation is located in the dorsomedial and posterior hypothalamic nuclei, the midbrain representation in the caudal part of the lateral/dorsolateral periaqueductal gray, the thalamic representation primarily in parts of the paraventricular and reuniens thalamic nuclei, and the cortical representation in prelimbic cortex. The hypothalamic power-dominance representation is located in the anterior hypothalamic nucleus, dorsomedial aspect of the ventromedial nucleus, and in adjacent parts of the medial preoptic area. The corresponding midbrain representation occurs in rostral part of the lateral/dorsolateral periaqueductal gray, and the thalamic representation in parts of the paraventricular, parataenial, and reuniens thalamic nuclei. We discuss sensory/mnemonic inputs to these representations, and outputs to premotor structures in the medulla, caudate-putamen, and cortex, and their differential contributions to involuntary, learned sequential, and voluntary motor acts. We examine potential contributions of neuronal activities in these representations to the subjective awareness of fear and anger. PMID:12367590
The mechanism of the sensory-to-motor transformation as well as motor-to-sensory transformation of human beings has attracted much attention in recent years. As no efficient device can record hand intrinsic behavior, it is difficult to get its neuro-physiological models of sensory-motor coordination. In this paper, we offer a system to acquire the kinematics and kinetics information of human hand movement through
Sensory experience profoundly shapes neural circuitry of juvenile brain. Although the visual cortex of adult rodents retains a capacity for plasticity in response to monocular visual deprivation, the nature of this plasticity and the neural circuit changes that accompany it remain enigmatic. Here, we investigate differences between adult and juvenile ocular dominance plasticity using Fourier optical imaging of intrinsic signals in mouse visual cortex. This comparison reveals that adult plasticity takes longer than in the juvenile mouse, is of smaller magnitude, has a greater contribution from the increase in response to the open eye, and has less effect on the hemisphere ipsilateral to the deprived eye. Binocular deprivation also causes different changes in the adult. Adult plasticity is similar to juvenile plasticity in its dependence on signaling through NMDA receptors. We propose that adult ocular dominance plasticity arises from compensatory mechanisms that counterbalance the loss of afferent activity caused by visual deprivation. PMID:18842887
Sensory experience profoundly shapes neural circuitry of juvenile brain. Although the visual cortex of adult rodents retains a capacity for plasticity in response to monocular visual deprivation, the nature of this plasticity and the neural circuit changes that accompany it remain enigmatic. Here we investigate differences between adult and juvenile ocular dominance plasticity using Fourier optical imaging of intrinsic signals in mouse visual cortex. This comparison reveals that adult plasticity takes longer than in the juvenile mouse, is of smaller magnitude, has a greater contribution from the increase in response to the open eye, and has less effect on the hemisphere ipsilateral to the deprived eye. Binocular deprivation also causes different changes in the adult. Adult plasticity is similar to juvenile plasticity in its dependence on signaling through NMDA receptors. We propose that adult ocular dominance plasticity arises from compensatory mechanisms that counterbalance the loss of afferent activity caused by visual deprivation.
Sensory systems detect small molecules, mechanical perturbations, or radiation via the activation of receptor proteins and downstream signaling cascades in specialized sensory cells. In vertebrates, the two principal categories of sensory receptors are ion channels, which mediate mechanosensation, thermosensation, and acid and salt taste; and G-protein-coupled receptors (GPCRs), which mediate vision, olfaction, and sweet, bitter, and umami tastes. GPCR-based signaling in rods and cones illustrates the fundamental principles of rapid activation and inactivation, signal amplification, and gain control. Channel-based sensory systems illustrate the integration of diverse modulatory signals at the receptor, as seen in the thermosensory/pain system, and the rapid response kinetics that are possible with direct mechanical gating of a channel. Comparisons of sensory receptor gene sequences reveal numerous examples in which gene duplication and sequence divergence have created novel sensory specificities. This is the evolutionary basis for the observed diversity in temperature- and ligand-dependent gating among thermosensory channels, spectral tuning among visual pigments, and odorant binding among olfactory receptors. The coding of complex external stimuli by a limited number of sensory receptor types has led to the evolution of modality-specific and species-specific patterns of retention or loss of sensory information, a filtering operation that selectively emphasizes features in the stimulus that enhance survival in a particular ecological niche. The many specialized anatomic structures, such as the eye and ear, that house primary sensory neurons further enhance the detection of relevant stimuli. PMID:22110046
TYPICALLY THE EXPERIMENTAL CONDITION FOR SENSORY DEPRIVATION RESEARCH CONSISTS OF AN ORDINARY SINGLE HOSPITAL ROOM, CONTAINING A NORMAL HOSPITAL BED. THE PATIENT REMAINS IN A ROOM DARKENED BY HEAVY CURTAINS, LYING OR SITTING IN BED, WEARING TRANSLUCENT EYE-GOGGLES, AND WITH HANDS AND ARMS ENCASED IN CARDBOARD CYLINDERS. PRACTICAL CLINICAL EXPERIENCE SUPPORTS THE USE OF RESTRAINT OR ISOLATION PROCEDURES WITH AGITATED
Infusion of prostaglandin (PG) D2 into the lateral ventricle of the brain induced an increase in the amount of non-rapid eye movement sleep in wild-type (WT) mice but not in mice deficient in the PGD receptor (DP). Immunofluorescence staining of WT mouse brain revealed that DP immunoreactivity was dominantly localized in the leptomeninges (LM) of the basal forebrain but that PGD synthase immunoreactivity was widely distributed in the LM of the entire brain. Electron microscopic observation indicated that DP-immunoreactive particles were predominantly located on the plasma membranes of arachnoid trabecular cells of the LM. The region with the highest DP immunoreactivity was clearly defined as bilateral wings in the LM of the basal forebrain located lateral to the optic chiasm in the proximity of the ventrolateral preoptic area, one of the putative sleep centers, and the tuberomammillary nucleus, one of the putative wake centers. The LM of this region contained DP mRNA 70-fold higher than that in the cortex as judged from the results of quantitative reverse transcription–PCR. PGD2 infusion into the subarachnoid space of this region increased the extracellular adenosine level more than 2-fold in WT mice but not in the DP-deficient mice. These results indicate that DPs in the arachnoid trabecular cells of the basal forebrain mediate an increase in the extracellular adenosine level and sleep induction by PGD2.
A significant concept in neuroscience is that sensory areas of the neocortex have evolved the remarkable ability to represent a number of stimulus features within the confines of a global map of the sensory periphery. Modularity, the term often used to describe the inhomogeneous nature of the neocortex, is without a doubt an important organizational principle of early sensory areas, such as the primary visual cortex (V1). Ocular dominance columns, one type of module in V1, are found in many primate species as well as in carnivores. Yet, their variable presence in some New World monkey species and complete absence in other species has been enigmatic. Here, we demonstrate that optical imaging reveals the presence of ocular dominance columns in the superficial layers of V1 of owl monkeys (Aotus trivirgatus), even though the geniculate inputs related to each eye are highly overlapping in layer 4. The ocular dominance columns in owl monkeys revealed by optical imaging are circular in appearance. The distance between left eye centers and right eye centers is approximately 650??m. We find no relationship between ocular dominance centers and other modular organizational features such as orientation pinwheels or the centers of the cytochrome oxidase blobs. These results are significant because they suggest that functional columns may exist in the absence of obvious differences in the distributions of activating inputs and ocular dominance columns may be more widely distributed across mammalian taxa than commonly suggested.
Kaskan, Peter M.; Lu, Haidong D.; Dillenburger, Barbara C.; Roe, Anna W.; Kaas, Jon H.
Introduction and Purpose: To investigate the effect of exodeviation in spatial visual attention using the illusory line motion paradigm. Methods: The perception of visual illusion (i.e., illusory line motion) in the dominant and nondominant eyes was examined in 12 control subjects (under 5(?)), 12 exophoria patients (over 10(?)), and 12 exotropia patients. This paradigm presents two cues followed by an instantaneously presented horizontal bar, which the subjects perceive as bars that emanate from the two priming cues. These bars appear to grow toward the center of the visual field and continue to move inward until they collide with each other. In these experiments, the priming cues were asynchronously and simultaneously presented. Results: In the dominanteye, there was no correlation between the collision point shift and the ocular deviation, regardless of the stimulus patterns. However, a correlation was noted between the collision point shift and the ocular deviation in the nondominant eye when the second cue was presented in the nasal hemi-retina (P < 0.01). The shift of the collision point in exophoria and exotropia was greater than that seen in the control subjects (P < 0.01). When there was simultaneous presentation of the two cues in the nasal and temporal hemi-retina, there was a difference in the shift of the collision point in the exotropia patients, as compared to both the control subjects and exophoria patients (P < 0.05). Conclusions: Current findings strongly suggest that sensory adaptation in the nondominant eye compensates for visual stress with ocular deviation. PMID:21149193
A novel ENU-induced mutation in the mouse leading to a nuclear and zonular opacity of the eye lens (Aey1) was mapped to chromosome 1 between the markers D1Mit303 and D1Mit332. On the basis of the chromosomal position, the g-crystallin encoding gene cluster (Cryg) and the bA2-crystallin encoding gene Cryba2 were tested as candidate genes. An A ! T mutation destroys
Jochen Graw; Norman Klopp; Jana Loster; Dian Soewarto; Helmut Fuchs; Johannes Becker-Follmann; Eckhard Wolf; Rudi Balling; Martin Hrabede Angelis
Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are Conjunctivitis - also known as pinkeye. Conjunctivitis is ...
Somatosensory deficit syndromes represent a common impairment following stroke and have a prevalence rate of around 80% in stroke survivors. These deficits restrict the ability of survivors to explore and manipulate their environment and are generally associated with a negative impact on quality of life and personal safety. Sensory impairments affect different sensory modalities in diverse locations at varying degrees, ranging from complete hemianesthesia of multiple modalities to dissociated impairment of somatosensory submodalities within a particular region of the body. Sensory impairments induce typical syndromal patterns which can be differentiated by means of a careful neurological examination, allowing the investigator to deduce location and size of the underlying stroke. In particular, a stroke located in the brainstem, thalamus, and the corticoparietal cortex result in well-differentiable sensory syndromes. Sensory function following stroke can be regained during rehabilitation even without specific sensory training. However, there is emerging evidence that specialized sensory interventions can result in improvement of somatosensory and motor function. Herein, we summarize the clinical presentations, examination, differential diagnoses, and therapy of sensory syndromes in stroke. PMID:22377851
Klingner, Carsten M; Witte, Otto W; Günther, Albrecht
Research on the senses spans the enormous range from analysis of individual molecules involved in sensory transduction to the attempted elucidation of conscious sensation. Because the variety of conceptual and experimental approaches varies so broadly across the field, it is impossible to delineate a single direction for future research. Two trends are nonetheless apparent. At the reductionistic end of the spectrum, in the analysis of sensory transduction, studies on all the senses will increasingly be driven by the techniques of molecular biology. The advent of techniques for producing cDNA libraries from small ensembles of receptor cells, or even from individual cells, will permit the recognition of new constituents of receptor cells and of factors involved in their specification, differentiation, and maintenance. In the integrative realm of sensory neurobiology, future studies will increasingly rely on optical techniques for the study of activity patterns on the surfaces of sensory areas of the cerebral cortex and on noninvasive functional imaging for the investigation of neural responses in human subjects. These techniques will continue to strengthen our understanding of the relation between neuronal activity and conscious sensory experience. PMID:9751666
The eyes are complex sensory organs and are designed to optimize vision under conditions of varying light. There are a number of eye disorders that can influence vision. Eye disorders among the elderly are a major health problem. With advancing age, the normal function of eye tissues decreases and there is an increased incidence of ocular pathology. The most common
The eyes are complex sensory organs and are designed to optimize vision under conditions of varying light. There are a number\\u000a of eye disorders that can influence vision. Eye disorders among the elderly are a major health problem. With advancing age,\\u000a the normal function of eye tissues decreases and there is an increased incidence of ocular pathology. The most common
U. Rajendra Acharya; Wong Li Yun; E. Y. K. Ng; Wenwei Yu; Jasjit S. Suri
Progressive external ophthalmoplegia (PEO) can be caused by a disorder characterized by multiple mitochondrial DNA (mtDNA) deletions due to mutations in the TWINKLE gene, encoding a mtDNA helicase. We describe a 71-year-old woman who had developed PEO at age 55 years. She had cataracts, diabetes, paresthesias, cognitive defects, memory problems, hearing loss, and sensory ataxia. She had muscle weakness with ragged red fibers on biopsy. MRI showed static white matter changes. A c.908G>A substitution (p.R303Q) in the TWINKLE gene was identified. Multiple mtDNA deletions were detected in muscle but not blood by a PCR-based method, but not by Southern blot analysis. MtDNA copy number was maintained in blood and muscle. A systematic literature search was used to identify the genotypic and phenotypic spectrum of dominant TWINKLE-related disease. Patients were adults with PEO and symptoms including myopathy, neuropathy, dysarthria or dysphagia, sensory ataxia, and parkinsonism. Diabetes, cataract, memory loss, hearing loss, and cardiac problems were infrequent. All reported mutations clustered between amino acids 303 and 508 with no mutations at the N-terminal half of the gene. The TWINKLE gene should be analyzed in adults with PEO even in the absence of mtDNA deletions in muscle on Southern blot analysis, and of a family history for PEO. The pathogenic mutations identified 5' beyond the linker region suggest a functional role for this part of the protein despite the absence of a primase function in humans. In our patient, the pathogenesis involved multiple mtDNA deletions without reduction in mtDNA copy number. PMID:19353676
Van Hove, Johan L K; Cunningham, Vicki; Rice, Cathlin; Ringel, Steven P; Zhang, Qing; Chou, Ping-Chieh; Truong, Cavatina K; Wong, Lee-Jun C
Foraging mode influences the dominantsensory modality used by a forager and likely the strategies of information gathering\\u000a used in foraging and anti-predator contexts. We assessed three components of visual information gathering in a sit-and-wait\\u000a avian predator, the black phoebe (Sayornis nigricans): configuration of the visual field, degree of eye movement, and scanning behavior through head-movement rates. We found\\u000a that
Familial burning feet syndrome inherited as an autosomal dominant trait has been described in only one family. Due to an associated sensory neuropathy the autosomal dominant burning feet syndrome was suggested to represent a variant form of hereditary sensory and autonomic neuropathy type I (HSAN I). Clinical, histopathological, and molecular genetic studies were performed in a large German kindred with autosomal dominant burning feet syndrome. The autosomal dominant burning feet syndrome was associated with a neuropathy predominantly affecting small unmyelinated nerve fibres. Linkage to the HSAN I locus on chromosome 9q22 and to the Charcot-Marie-Tooth disease type 2B (CMT 2B) locus on chromosome 3q13-q22 was excluded. The autosomal dominant burning feet syndrome is neither allelic to HSAN I nor to CMT 2B and thus represents a distinct genetic entity.??
The idea that the cutaneous surface may be employed as a substitute for the eyes and ears is by no means a modern notion. Although the sense of touch has long been considered as a surrogate for both the visual and auditory modalities, the focus of this chapter will be on the efforts to develop a tactile substitute for hearing, especially that of human speech. The visual system is our primary means of processing information about environmental space such as orientation, distance, direction and size. It is much less effective in making temporal discriminations. The auditory system is unparalleled in processing information that involves rapid sequences of temporal events, such as speech and music. The tactile sense is capable of processing both spatial and temporal information although not as effective in either domain as the eye or the ear.
The research carried out during the period of the grant continued several lines of investigation on the way in which sensory and high-level influences contribute to the control of smooth and saccadic eye movements and on the perceptual implications of eye...
Eye injuries frequently occur in the home, at work and at play. Many result in legally blind eyes, and most are preventable. Awareness of potential hazards is essential to preventing eye injuries, particularly in children. In addition, protective devices must be used appropriately. We have developed eye protectors that have proved effective in reducing both the overall incidence and the severity of sports eye injuries. ImagesFigures 2a, bFigure 3Figures 4a, b, c, dFigure 5
Purpose Unilateral peripheral prisms for homonymous hemianopia (HH) place different images on corresponding peripheral retinal points, a rivalrous situation in which local suppression of the prism image could occur and thus limit device functionality. Detection with peripheral prisms has primarily been evaluated using conventional perimetry where binocular rivalry is unlikely to occur. We quantified detection over more visually complex backgrounds and examined the effects of ocular dominance. Methods Detection rates of 8 participants with HH or quadranopia and normal binocularity wearing unilateral peripheral prism glasses were determined for static perimetry targets briefly presented in the prism expansion area (in the blind hemifield) and the seeing hemifield, under monocular and binocular viewing, over uniform gray and more complex patterned backgrounds. Results Participants with normal binocularity had mixed sensory ocular dominance, demonstrated no difference in detection rates when prisms were fitted on the side of the HH or the opposite side (p>0.2), and had detection rates in the expansion area that were not different for monocular and binocular viewing over both backgrounds (p>0.4). However, two participants with abnormal binocularity and strong ocular dominance demonstrated reduced detection in the expansion area when prisms were fitted in front of the non-dominanteye. Conclusions We found little evidence of local suppression of the peripheral prism image for HH patients with normal binocularity. However, in cases of strong ocular dominance, consideration should be given to fitting prisms before the dominanteye. Although these results are promising, further testing in more realistic conditions including image motion is needed.
Ross, Nicole C.; Bowers, Alex R.; Optom, M.C.; Peli, Eli
Suppose that the variability in our movements1–9 is caused not by noise in the motor system itself, nor by fluctuations in our intentions or plans, but rather by errors in our sensory estimates of the external parameters that define the appropriate action. For tasks in which precision is at a premium, performance would be optimal if no noise were added in movement planning and execution: motor output would be as accurate as possible given the quality of sensory inputs. Here we use visually guided smooth-pursuit eye movements in primates10 as a testing ground for this notion of optimality. In response to repeated presentations of identical target motions, nearly 92% of the variance in eye trajectory can be accounted for as a consequence of errors in sensory estimates of the speed, direction and timing of target motion, plus a small background noise that is observed both during eye movements and during fixations. The magnitudes of the inferred sensory errors agree with the observed thresholds for sensory discrimination by perceptual systems, suggesting that the very different neural processes of perception and action are limited by the same sources of noise.
Osborne, Leslie C.; Lisberger, Stephen G.; Bialek, William
Included in the collection are articles on sensory-motor sequencing experiences in learning by R.G. Heckelman, integrating form perception by Floria Coon-Teters, building patterns of retention by Harold Helms, hand-eye coordination by Shirley Linn, laterality and directionality by Sheila Benyon, body image and body awareness by Grace Petitclerc,…
|Included in the collection are articles on sensory-motor sequencing experiences in learning by R.G. Heckelman, integrating form perception by Floria Coon-Teters, building patterns of retention by Harold Helms, hand-eye coordination by Shirley Linn, laterality and directionality by Sheila Benyon, body image and body awareness by Grace Petitclerc,…
Sensory exploitation predicts that female mate preferences exist before the evolution of exaggerated male ornaments. We tested this prediction by estimating female preference functions, remating intervals, and copulation durations for three species of stalk-eyed flies. Two species, Cyrtodiopsis whitei and C dahnanni, exhibit extreme sexual dimorphism in eye span, with eye stalks exceeding body length in large males. In contrast,
Gerald S. Wilkinson; Heidi Kahler; Richard H. Baker
In the area of product design, sensorydominance can be defined as the relative importance of different sensory modalities for product experience. Since product experience is multisensory, it is interesting to know which sensory modality plays a leading role in a particular experience, so that designers could concentrate on the creation of the most relevant product properties. It is often
Anna Fenko; Hendrik N. J. Schifferstein; Paul Hekkert
Vision is the dominant sense, and the eyes are connected with almost every other part of the brain. If the vision system is poorly developed, children trying to learn suffer. Without good up close vision, students are handicapped even if no one knows or suspects it--they may not even know it themselves. Students do not know that the way they see…
The knowledge and understanding of the development of the sensory systems in the fetus, neonate, and infant have progressed and grown extensively in the past twenty to thirty years. This has been a result of the advances in technology for study of brain development and the sensory systems specifically. While the basic physcial structure of the sensory receptors (i.e. eyes,
Eye injuries come at a high cost to society and are avoidable. Ocular blast injuries can be primary, from the blast wave itself; secondary, from fragments carried by the blast wind; tertiary; due to structural collapse or being thrown against a fixed object; or quaternary, from burns and indirect injuries. Ballistic eye protection significantly reduces the incidence of eye injuries and should be encouraged from an early stage in Military training. Management of an injured eye requires meticulous history taking, evaluation of vision that measures the acuity and if there is a relative pupillary defect as well as careful inspection of the eyes, under anaesthetic if necessary. A lateral canthotomy with cantholysis should be performed immediately if there is a sight-threatening retrobulbar haemorrhage. Systemic antibiotics should be prescribed if there is a suspected penetrating or perforating injury. A ruptured globe should be protected by an eye shield. Primary repair of ruptured globes should be performed in a timely fashion. Secondary procedures will often be required at a later date to achieve sight preservation. A poor initial visual acuity is not a guarantee of a poor final result. The final result can be predicted after approximately 3–4 weeks. Future research in eye injuries attempts to reduce scarring and neuronal damage as well as to promote photoreceptor rescue, using post-transcriptional inhibition of cell death pathways and vaccination to promote neural recovery. Where the sight has been lost sensory substitution of a picture from a spectacle mounted video camera to the touch receptors of the tongue can be used to achieve appreciation of the outside world.
Objectives The National Social Life, Health, and Aging Project assessed functioning of all 5 senses using both self-report and objective measures. We evaluate the performance of the objective measures and model differences in sensory function by gender and age. In the process, we demonstrate how to use and interpret these measures. Methods Distance vision was assessed using a standard Sloan eye chart, and touch was measured using a stationary 2-point discrimination test applied to the index fingertip of the dominant hand. Olfactory function (both intensity detection and odor identification) was assessed using odorants administered via felt-tip pens. Gustatory function was measured via identification of four taste strips. Results The performance of the objective measures was similar to that reported for previous studies, as was the relationship between sensory function and both gender and age. Discussion Sensory function is important in studies of aging and health both because it is an important health outcome and also because a decline in functioning can be symptomatic of or predict other health conditions. Although the objective measures provide considerably more precision than the self-report items, the latter can be valuable for imputation of missing data and for understanding differences in how older adults perceive their own sensory ability.
A series of simple activities not only illustrates how our eyes work but also dramatically shows how the brain interprets the eyes' information. Uses these activities to introduce a study of the eye to elementary students and to motivate their interest. (Author/RK)
\\u000a Sensory integration dysfunction (SID) (also known as regulatory sensory processing disorder, sensory processing dysfunction,\\u000a or sensory processing dysfunction) is a neurological disorder that involves impairment in processing data from the different\\u000a senses (vision, auditory, touch, olfaction, and taste), the vestibular system (movement), and proprioception (body awareness).
Nociception results in peripheral and central changes in sensory processing. These changes are considered to significantly\\u000a contribute to postoperative pain and its outcome. Objective measures of changes in sensory processing are now being studied\\u000a in humans after surgery. Surgical nociception leads to both central excitation (eg, spinal sensitization) and central inhibition (eg, descending inhibition), with inhibition being the dominant response
... Yes These may be signs of a serious eye infection called PERIORBITAL CELLULITIS. URGENT SEE YOUR DOCTOR RIGHT AWAY. No 12. Is there a firm, painful lump in the ... 13. Is the white of the eye pink, red or irritated, and are there any ...
|A simple test of ocular dominance in infants is described. In the test, a small point of light is gradually brought closer to the observer along the medial plane. As the light draws closer, in typical cases, one eye will cease to converge, or frequently, it will break from convergence suddenly. The eye which ceases converging or breaks away from…
SUMMARY A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled in- dividuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes attached above and beside the dominanteye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift.
The purpose of the study was to investigate the occurrence of lateral dominance problems in a sample of children with learning disabilities. Ninety-one children (62 boys, 29 girls) who attended a school for children with learning disabilities were selected for the study. The Harris tests of lateral dominance were administered individually, and the children were rated as having right, left, or mixed dominance for hand, eye, and foot. When compared with normative data on dominance in children, the results showed that the occurrence of mixed hand dominance was no more frequent, the occurrence of mixed eyedominance was less frequent, and the occurrence of mixed foot dominance was more frequent in the children with learning disabilities. Results also showed that the occurrence of mixed and crossed eye-hand dominance was significantly different in children with learning disabilities when compared with children without learning disabilities. However, the occurrence of mixed eye-hand dominance was found to be significantly greater in children without learning disabilities than in learning disabled children. Age and sex were not found to affect the occurrence of lateral dominance problems in children with learning disabilities. PMID:6823468
A growing body of evidence is available about the functioning of fetal sensory systems during gestation. This article aims at reviewing data concerning (i) the presence of potential sensory stimulation in the fetal milieu, (ii) the sequential functional development of the sensory systems and (iii) physiological and behavioral responses of fetuses to various types of stimulation. Human data are compared
|This manual is intended to provide information leading to reliable assessment of vision and hearing capabilities of children considered to have dual sensory impairments. Ongoing sensory assessment is necessary to determine the extent of residual sensory abilities that should be considered in educational programming decisions and to determine any…
This paper explores how the military can establish 'cyber-dominance' in the battlespace of today and in the future. Cyberspace has its own challenges as an arena in which to conduct warfare just like land, sea, air and space do. This poses common problems...
... therapy uses high-powered energy beams, such as protons or gamma rays, to kill cancer cells. Radiation ... from a machine that directs radiation, such as proton beams, to your eye (external beam radiation or ...
The vertebrate eye is composed of both surface ectodermal and neuroectodermal derivatives that evaginate laterally from an epithelial anlage of the forming diencephalon. The retina is composed of a limited number of neuronal and non-neuronal cell types and is seen as a model for the brain with reduced complexity. The eye develops in a stereotypic manner building on evolutionarily conserved molecular networks. Eye formation is initiated at the onset of gastrulation by the determination of the eye field in the anterior neuroectoderm. Homeobox transcription factors, in particular Six3 are crucially involved in the establishment and maintenance of retinal identity. The eye field expands by proliferation as gastrulation proceeds and is initially confined to a single retinal primordium by the differential activity of specifying transcription factors. This central field is subsequently split in response to secreted factors emanating from the ventral midline. Concomitant with medio-lateral patterning at the onset of neurulation, morphogenesis sets in and laterally evaginates the optic vesicle. Strikingly during this process the neuroectoderm in the eye field transiently loses epithelial features and cells migrate individually. In a second morphogenetic event, the vesicle is transformed into the optic cup, concomitant with onset and progression of retinal differentiation. Accompanying optic cup morphogenesis, neural differentiation is initiated from a retinal signalling centre in a stereotypic and species specific manner by secreted signalling factors. Here we will give an overview of key events during vertebrate eye formation and highlight key players in the respective processes. PMID:23684892
A contribution to a handbook on psychonomy relating to sensory functions is presented. The properties of the human eye are described, including optical image formation, image quality, the retina, photometry, light and dark adaptation, and color vision.
The human body has five basic sensory functions: touch, vision, hearing, taste, and smell. The effectiveness of one or more of these human sensory functions can be impaired as a result of trauma, congenital defects, or the normal ageing process. Converting one type of function into another, or translating a function to a different part of the body, could result in a better quality of life for a person with diminished sensorial capabilities.
Patients with homonymous visual field defects (HVFD) are often crucially disabled during self-guided visual exploration of their natural environment. Abnormal visual search may be related to the sensory deficit, deficient spatial orientation or compensatory eye movements. We tested the hypothesis that visual search in HVFD is purely determined by the visual–sensory deficit by comparing nine patients with HVFD due to
Björn Machner; Andreas Sprenger; Detlef Kömpf; Thurid Sander; Wolfgang Heide; Hubert Kimmig; Christoph Helmchen
Malignant melanoma - choroid; Malignant melanoma - eye; Eye tumor; Ocular melanoma ... affect several parts of the eye, including the: Choroid Ciliary body Conjunctiva Eyelid Iris Orbit The choroid ...
... helps you gather important information such as medical history, medical and personal contact information, legal documentation, allergies, etc., and keep it handy to take with you to the hospital. Click below to download: The Eyes in Marfan syndrome CALL OUR HELP CENTER: 800-8-MARFAN ...
|Beverage take-out trays are funky in their form and function. In this article, the author describes how to make googly eye masks out of discarded take-out trays and other common recycled or discarded materials. (Contains 1 online resource.)|
Background Arthritis of the hand can limit a person’s ability to perform daily activities. Whether or not sensory deficits contribute to the disability in this population remains unknown. The primary purpose of this study was to determine if women with osteoarthritis (OA) or rheumatoid arthritis (RA) of the hand have sensory impairments. Methods Sensory function in the dominant hand of women with hand OA or RA and healthy women was evaluated by measuring sensory nerve action potentials (SNAPs) from the median, ulnar and radial nerves, sensory mapping (SM), and vibratory and current perception thresholds (VPT and CPT, respectively) of the second and fifth digits. Results All SNAP amplitudes were significantly lower for the hand OA and hand RA groups compared with the healthy group (p?0.05). No group differences were found for SNAP conduction velocities, SM, VPT, and CPT. Discussion We propose, based on these findings, that women with hand OA or RA may have axonal loss of sensory fibers in the median, ulnar and radial nerves. Less apparent were losses in conduction speed or sensory perception.
|This study examined the relationship between auditory, visual, touch, and oral sensory dysfunction in autism and their relationship to multisensory dysfunction and severity of autism. The Sensory Profile was completed on 104 persons with a diagnosis of autism, 3 to 56 years of age. Analysis showed a significant correlation between the different…
Kern, Janet K.; Trivedi, Madhukar H.; Grannemann, Bruce D.; Garver, Carolyn R.; Johnson, Danny G.; Andrews, Alonzo A.; Savla, Jayshree S.; Mehta, Jyutika A.; Schroeder, Jennifer L.
This study examined the relationship between auditory, visual, touch, and oral sensory dysfunction in autism and their relationship to multisensory dysfunction and severity of autism. The Sensory Profile was completed on 104 persons with a diagnosis of autism, 3 to 56 years of age. Analysis showed a significant correlation between the different…
Kern, Janet K.; Trivedi, Madhukar H.; Grannemann, Bruce D.; Garver, Carolyn R.; Johnson, Danny G.; Andrews, Alonzo A.; Savla, Jayshree S.; Mehta, Jyutika A.; Schroeder, Jennifer L.
This study examined the relationship between auditory, visual, touch, and oral sensory dysfunction in autism and their relationship to multisensory dysfunction and severity of autism. The Sensory Profile was completed on 104 persons with a diagnosis of autism, 3 to 56 years of age. Analysis showed a significant correlation between the different processing modalities using total scores. Analysis also showed
Janet K. Kern; Madhukar H. Trivedi; Bruce D. Grannemann; Carolyn R. Garver; Danny G. Johnson; Alonzo A. Andrews; Jayshree S. Savla; Jyutika A. Mehta; Jennifer L. Schroeder
In one embodiment, the present invention provides a sensory testing system. In another embodiment, the present invention provides a method of using a sensory testing system to determine sensory pressure thresholds. In a further embodiment, the present inv...
Exposure to many neurotoxic compounds has been shown to produce a sensory system dysfunction. Neurophysiological assessment of sensory function in humans and animal models often uses techniques known as sensory evoked potentials. Because both humans and animals show analogous res...
|Provides an overview of presentations that were included in the Medical Symposium at the 1998 Learning Disabilities Association conference. The symposium addressed vestibular control and eye movement, postural sway and balance, cerebellar dysfunction, the role of the frontal lobe, developmental coordination disorder, and sensory integration…
... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye ... term for crossed eyes is strabismus. Children usually receive ...
... Foreign Body in Eye htmForeignBodyEye Eyelashes prevent most particles or objects from entering the eye, and tears usually are able to rinse out particles that do get in the eye. Occasionally, a ...
In the primary visual cortex of strabismic cats, the elimination of correlated activity between the two eyes enhances the segregation of the geniculocortical afferents into alternating ocular dominance domains. In addition, both tangential intracortical fibres and neuronal synchronization are severely reduced between neurons activated by different eyes. Consequently, ocular dominance columns belonging to different eyes are functionally rather independent. We
Siegrid Lowel; Kerstin E. Schmidt; Dae-Shik Kim; Fred Wolf; Frank Hoffsummer; Wolf Singer; Tobias Bonhoeffer
Pictorial images are icons as well as eye-cons: they provide distillations of objects or ideas into simpler shapes. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimensions of depth and motion are missing from icons, and these alone introduce all manner of potential ambiguities. The history of art can be considered as exploring the missing link between icon and object. Eye-cons can also be illusions—tricks of vision so that what is seen does not necessarily correspond to what is physically presented. Pictorial images can be spatialised or stylised; spatialised images generally share some of the projective characteristics of the object represented. Written words are also icons, but they do not resemble the objects they represent—they are stylised or conventional. Icons as stylised words and spatialised images were set in delightful opposition by René Magritte in a series of pipe paintings, and this theme is here alluded to. Most of visual science is now concerned with icons—two-dimensional displays on computer monitors. Is vision now the science of eye-cons?
Several sensory-motor integration regions have been identified in parietal cortex, which appear to be organized around motor-effectors (e.g., eyes, hands). We investigated whether a sensory-motor integration area might exist for the human vocal tract. Speech requires extensive sensory-motor integration, as does other abilities such as vocal…
|Several sensory-motor integration regions have been identified in parietal cortex, which appear to be organized around motor-effectors (e.g., eyes, hands). We investigated whether a sensory-motor integration area might exist for the human vocal tract. Speech requires extensive sensory-motor integration, as does other abilities such as vocal…
In this paper, we review evidence regarding differences in the types of sensory experiences of persons with ASD with respect to both unisensory and multisensory processing. We discuss selfreports, carer questionnaires as well as perceptual processing differences found in the laboratory. Incoming information is processed through one or more of our senses and fundamental differences in the processing of information from any sensory modality or combination of sensory modalities are likely to have cascading effects on the way individuals with ASD experience the world around them, effects that can have both positive and negative impact on a individual with ASD’s quality of life.
Stewart, Mary E.; Russo, Natalie; Banks, Jennifer; Miller, Louisa; Burack, Jacob A.
One goal of the experiment presented here was to check, in children, the relationship between eye preference when sighting at different angles and eyedominance in binocular rivalry. In addition, since it is sometimes argued that a crossed pattern of eye-hand preference might put children at risk of difficulties in learning to read, we evaluated the relationship between this pattern
Sensory conflict has been used to explain the way we perceive and control our self-motion, as well as the aetiology of motion sickness. However, recent research on simulated viewpoint jitter provides a strong challenge to one core prediction of these theories -- that increasing sensory conflict should always impair visually induced illusions of self-motion (known as vection). These studies show that jittering self-motion displays (thought to generate significant and sustained visual-vestibular conflict) actually induce superior vection to comparable non-jittering displays (thought to generate only minimal/transient sensory conflict). Here we review viewpoint jitter effects on vection, postural sway, eye-movements and motion sickness, and relate them to recent behavioural and neurophysiological findings. It is shown that jitter research provides important insights into the role that sensory interaction plays in self-motion perception. PMID:21864457
Palmisano, Stephen; Allison, Robert S; Kim, Juno; Bonato, Frederick
Biology provides examples of efficient machines which greatly outperform conventional technology. Designers in neuromorphic engineering aim to construct electronic systems with the same efficient style of computation. This task requires a melding of novel engineering principles with knowledge gleaned from neuroscience. We discuss recent progress in realizing neuromorphic sensory systems which mimic the biological retina and cochlea, and subsequent sensor processing. The main trends are the increasing number of sensors and sensory systems that communicate through asynchronous digital signals analogous to neural spikes; the improved performance and usability of these sensors; and novel sensory processing methods which capitalize on the timing of spikes from these sensors. Experiments using these sensors can impact how we think the brain processes sensory information. PMID:20493680
\\u000a This chapter reviews the expression and regulation of opioid receptors in sensory neurons and the interactions of these receptors\\u000a with endogenous and exogenous opioid ligands. Inflammation of peripheral tissues leads to increased synthesis and axonal transport\\u000a of opioid receptors in dorsal root ganglion neurons. This results in opioid receptor upregulation and enhanced G protein coupling\\u000a at peripheral sensory nerve terminals.
Different sensory organs, such the eye and ear, are widely thought to have separate origins, guided by distinct organ-specific factors that direct all aspects of their development. Previous studies of the D. melanogaster gene eyeless (ey) and its vertebrate homolog Pax6 suggested that this gene acts in such a manner and specifically drives eye development. But diverse sensory organs might instead arise by segment-specific modification of a developmental program that is involved more generally in sensory organ formation. In D. melanogaster, a common proneural gene called atonal (ato) functions in the initial process of development of a number of segment-specific organs, including the compound eye, the auditory organ and the stretch receptor, suggesting that these organs share an evolutionary origin. Here we show that D. melanogaster segment-specific sensory organs form through the integration of decapentaplegic (dpp), wingless (wg) and ecdysone signals into a single cis-regulatory element of ato. The induction of ectopic eyes by ey also depends on these signals for ato expression, and the ey mutant eye imaginal disc allows ato expression if cell death is blocked. These results imply that ey does not induce the entire eye morphogenetic program but rather modifies ato-dependent neuronal development. Our findings strongly suggest that various sensory organs evolved from an ato-dependent protosensory organ through segment specification by ey and Hox genes. PMID:14981517
Cortical circuits encode sensory stimuli through the firing of neuronal ensembles, and also produce spontaneous population patterns in the absence of sensory drive. This population activity is often characterized experimentally by the distribution of multineuron “words” (binary firing vectors), and a match between spontaneous and evoked word distributions has been suggested to reflect learning of a probabilistic model of the sensory world. We analyzed multineuron word distributions in sensory cortex of anesthetized rats and cats, and found that they are dominated by fluctuations in population firing rate rather than precise interactions between individual units. Furthermore, cortical word distributions change when brain state shifts, and similar behavior is seen in simulated networks with fixed, random connectivity. Our results suggest that similarity or dissimilarity in multineuron word distributions could primarily reflect similarity or dissimilarity in population firing rate dynamics, and not necessarily the precise interactions between neurons that would indicate learning of sensory features.
The purpose of this study was to examine sensory quadrants in autism based on Dunn's Theory of Sensory Processing. The data for this study was collected as part of a cross-sectional study that examined sensory processing (using the Sensory Profile) in 103 persons with autism, 3–43 years of age, compared to 103 age- and gender-matched community controls. Sensory quadrants (Low
Janet K. Kern; Carolyn R. Garver; Thomas Carmody; Alonzo A. Andrews; Madhukar H. Trivedi; Jyutika A. Mehta
A fundamental problem in the generation of goal-directed behaviour is caused by the inevitable latency of biological sensory\\u000a systems. Behaviour which is fully synchronised with the triggering sensory event can only be executed if the occurrence of\\u000a this event can be predicted based on prior information. Smooth-pursuit eye movements are a classical and well-established\\u000a example of goal-directed behaviour. The execution
The paper discusses the relation between local eye irritation testing and whole body irritation response using n-butanol as a model substance. (Note: A short-term eye exposure method using goggles has been developed to assess sensoryeye irritation of air...
Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... on the type of chromosome affected (autosomal or sex chromosome). It also depends on whether the trait ...
Both Web sites come from Science@NASA, an online source for news and information about NASA-funded research. The first article describes the work of researchers at the Center for Commercial Applications of Combustion in Space, who are developing artificial bones for long-lasting, pain-free hip and knee replacements. These ceramic bones are touted as "so much like the real thing that they could actually meld with living bone." Earlier this year, researchers at the Space Vacuum Epitaxy Center in Houston experimented with "photosensitive ceramic films that respond to light much as rods and cones do," the subject of the second Web site. Researchers hope these films will eventually be used to restore lost vision in human eyes. Each article is available as an audio file, and includes helpful diagrams and Web links for related articles and information.
The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate. The primate visual system is ideally suited for tasks within arm’s length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals.
The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm's length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals. PMID:23866932
|TWO DISPARATE STUDIES WERE REPLICATED WITH A PUBLIC SCHOOL POPULATION USED BY HILLERICH IN A 4-YEAR STUDY OF THE DEVELOPMENT OF HANDEDNESS AND EYEDNESS. SUBJECTS WERE 273 SEVENTH AND EIGHTH GRADERS WHO REMAINED FROM AN ORIGINAL POPULATION OF 400. TESTS WERE ADMINISTERED TO DETERMINE EYEDOMINANCE, HANDEDNESS, CONTROLLING EYE, READING ACHIEVEMENT,…
We examine the parameterized complexity of t\\u000a -Dominating Set, the problem of finding a set of at most k nodes that dominate at least t nodes of a graph G?=?(V,E). The classic NP-complete problem Dominating Set, which can be seen to be t\\u000a -Dominating Set with the restriction that t?=?n, has long been known to be W-complete when parameterized in k. Whereas this
Purpose – The purpose of this paper is to present the multi-sensory brand-experience concept in relation to the human mind and senses. It also seeks to propose a sensory marketing (SM) model of the multi-sensory brand-experience hypothesis. Design\\/methodology\\/approach – This paper applies exploratory and explanatory approaches to investigating the multi-sensory brand-experience concept within the context of discovery. The qualitative study
On Earth, gravity sensation plays a basic role for all of physiological phenomena in every creature. In microgravity, loss of gravity input causes many functional disorders in animals and humans. During adaptation to microgravity, otolith-mediated response such as eye movements would alter. Flatfish provide a natural model for the study of adaptive changes in the vestibuloocular reflex. During metamorphosis, vestibular and oculomotor coordinate of flatfish displaced 90 degrees about the longitudinal body axis. Therefore, it is expected that microgravity induce the sensory mismatch in adult flatfish. In this study, we analyzed the eye movements of normal and otolith removed flatfish for body tilting and the eye movements of normal flatfish during microgravity produced by parabolic aircraft flight. The fish was fixed on the tilting table controlled by computer. The eye movements for body tilting along the different body axis were video-recorded. The vertical and torsional eye rotations were analyzed frame by frame. In normal flatfish, torsional eye movements were larger for head up or head down tilting than leftward or rightward tilting. On the other hand, vertical eye movements were larger for leftward or rightward tilting than head up or head down tilting. After removal of left side utlicular otolith, the vertical eye movement for 180 degrees body tilting disappeared. For the changes of gravity, vertical eye movements were observed. These results suggested that eye movements of flatfish adapted to Earth's gravity condition and sacculus and lagena might play important role for otolith-ocular eye movements.
|This article features the National Institute of Trauma and Loss in Children (TLC), a program that has demonstrated via field testing, exploratory research, time series studies, and evidence-based research studies that its Structured Sensory Intervention for Traumatized Children, Adolescents, and Parents (SITCAP[R]) produces statistically…
|From children's viewpoints, what they experience in the world is what the world is like--for everyone. "What do others experience with their senses when they are in the same situation?" is a question that young children can explore by collecting data as they use a "feely box," or take a "sensory walk." There are many ways to focus the children's…
This lecture covers the sensory system. More specifically, it provides information about how the sensory system captures, transduces, amplifies, adapts, and passes information from one cell to the next.
A. James Hudspeth, Ph.D., M.D. (Howard Hughes Medical Institute;)
We present an analytical approach for studying the coupled development of ocular dominance and orientation preference columns. Using this approach we demonstrate that ocular dominance segregation can induce the stabilization and even the production of pinwheels by their crystallization in two types of periodic lattices. Pinwheel crystallization depends on the overall dominance of one eye over the other, a condition that is fulfilled during early cortical development. Increasing the strength of intermap coupling induces a transition from pinwheel-free stripe solutions to intermediate and high pinwheel density states. PMID:19519077
Motor dominance is well established, but sensorydominance is much less clear. We therefore studied the cortical evoked magnetic fields using magnetoencephalography (MEG) in a group of 20 healthy right handed subjects in order to examine whether standard electrical stimulation of the median and ulnar nerve demonstrated sensory lateralization. The global field power (GFP) curves, as an indication of cortical activation, did not depict sensory lateralization to the dominant left hemisphere. Comparison of the M20, M30, and M70 peak latencies and GFP values exhibited no statistical differences between the hemispheres, indicating no sensory hemispherical dominance at these latencies for each nerve. Field maps at these latencies presented a first and second polarity reversal for both median and ulnar stimulation. Spatial dipole position parameters did not reveal statistical left-right differences at the M20, M30 and M70 peaks for both nerves. Neither did the dipolar strengths at M20, M30 and M70 show a statistical left-right difference for both nerves. Finally, the Laterality Indices of the M20, M30 and M70 strengths did not indicate complete lateralization to one of the hemispheres. After electrical median and ulnar nerve stimulation no evidence was found for sensory hand dominance in brain responses of either hand, as measured by MEG. The results can provide a new assessment of patients with sensory dysfunctions or perceptual distortion when sensorydominance occurs way beyond the estimated norm. PMID:22080222
Chen, Andrew C N; Theuvenet, Peter J; de Munck, Jan C; Peters, Maria J; van Ree, Jan M; Lopes da Silva, Fernando L
Ninety-six samples of vinegars of different sources were subjected to sensory analysis. For white vinegars, Linear Discriminant Analysis showed that sensory analysis could be used to distinguish between the different sources of vinegar, and especially to discriminate between alcohol and apple vinegars from wine vinegars on the basis of only seven sensory parameters. Principal Component Regression showed that the quality
Vincenzo Gerbi; Giuseppe Zeppa; Andrea Antonelli; Alberta Carnacini
This brief paper summarizes what is known about sensory integration and sensory integration dysfunction (DSI). It outlines evaluation of DSI, treatment approaches, and implications for parents and teachers, including compensatory strategies for minimizing the impact of DSI on a child's life. Review of origins of sensory integration theory in the…
The simple anatomy, behavior, and genetics of the nematode Caenorhabditis elegans make it an attractive organism for studying sensory circuits and their functions in vivo. Recent advances in our understanding of C. elegans sensory signaling stem from work on topographic maps, chemosensory receptors, modality coding, and the integration of antagonistic sensory inputs.
The amplitude of electrically-evoked mass action potentials recorded in the spinal cord and brainstem has been reported to decrease only during eye movement events of active sleep. In contrast, we have reported that the response of trigeminal sensory neurons to peripheral stimuli is modulated throughout the behavioral state of active sleep. It is unclear whether eye movement events contribute to
Brian E. Cairns; Tony Kiang; Shelly A. McErlane; Miguel C. Fragoso; Peter J. Soja
... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ... The extraocular muscles of the eye (external to the eyeball) control the positioning of the eyes. They coordinate of the eye ...
Español Media Inquiries find an eye M.D. ask an eye M.D. Search GetEyeSmart.org Diseases & Conditions A ... Adults 40 to 60 Adults Over 60 Babies & Children Computer Usage Diabetes Diet & Nutrition Eye Screening Guidelines ...
The purpose of this study was to examine the postural control in children with strabismus before and after eye surgery. Control of posture is a complex multi-sensorial process relying on visual, vestibular and proprioceptive systems. Reduced influence of one of such systems leads to postural adaptation due to a compensation of one of the other systems . Nine children with
Agathe Legrand; Emmanuel Bui Quoc; Sylvette Wiener Vacher; Jérôme Ribot; Nicolas Lebas; Chantal Milleret; Maria Pia Bucci
In the lateral eye of the horseshoe crab, Limulus, the visual receptor units exert an inhibitory influence mutually upon one another. The discharge of impulses in any one optic nerve fiber, generated in the sensory structure of the particular ommatidium from which that fiber arises, is determined prin- cipally by the intensity of the light stimulus to the ommstidium and
|Hereditary sensory and autonomic neuropathies (HSAN) are clinically and genetically heterogeneous disorders characterized by axonal atrophy and degeneration, exclusively or predominantly affecting the sensory and autonomic neurons. So far, disease-associated mutations have been identified in seven genes: two genes for autosomal dominant ("SPTLC1"…
Rotthier, Annelies; Baets, Jonathan; De Vriendt, Els; Jacobs, An; Auer-Grumbach, Michaela; Levy, Nicolas; Bonello-Palot, Nathalie; Kilic, Sara Sebnem; Weis, Joachim; Nascimento, Andres; Swinkels, Marielle; Kruyt, Moyo C.; Jordanova, Albena; De Jonghe, Peter; Timmerman, Vincent
BackgroundDifferent strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families.Methodology\\/Principal FindingsWe used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of
Colleen T. ORourke; Margaret I. Hall; Todd Pitlik; Esteban Fernández-Juricic
Sensory chemical ecology is the branch of chemical ecology that focuses on chemical communications between organisms and chemical\\u000a sensing of the environment by organisms. Algae are well known to have numerous physiological responses to variations in their\\u000a chemical environment, particularly with respect to nutrients (Lobban and Harrison 1994). However, with respect to environmental\\u000a sensing it is typical for “chemical ecology”
In arthropods, the modified primary cilium is a structure common to all peripheral sensory neurons other than photoreceptors. Since its first description in 1958, it has been investigated in great detail in numerous sense organs (sensilla) of many insect species by means of electron microscopy and electrophysiology. The perfection of molecular biological methods has led to an enormous advance in our knowledge about development and function of sensory cilia in the fruitfly since the end of the last century. The cilia show a wealth of adaptations according to their different physiological roles: chemoreception, mechanoreception, hygroreception, and thermoreception. Divergent types of receptors and channels have evolved fulfilling these tasks. The number of olfactory receptor genes can be close to 300 in ants, whereas in crickets slightest mechanical stimuli are detected by the interaction of extremely sophisticated biomechanical devices with mechanosensory cilia. Despite their enormous morphological and physiological divergence, sensilla and sensory cilia develop according to a stereotyped pattern. Intraflagellar transport genes have been found to be decisive for proper development and function. PMID:22814269
Background Vestibular reflexes coordinate movements or sensory input with changes in body or head position. Vestibular-evoked responses that involve the extraocular muscles include the vestibulo-ocular reflex (VOR), a compensatory eye movement to stabilize retinal images. Although an angular VOR attributable to semicircular canal stimulation was reported to be absent in free-swimming zebrafish larvae, recent studies reveal that vestibular-induced eye movements can be evoked in zebrafish larvae by both static tilts and dynamic rotations that tilt the head with respect to gravity. Results We have determined herein the basis of sensitivity of the larval eye movements with respect to vestibular stimulus, developmental stage, and sensory receptors of the inner ear. For our experiments, video recordings of larvae rotated sinusoidally at 0.25 Hz were analyzed to quantitate eye movements under infrared illumination. We observed a robust response that appeared as early as 72 hours post fertilization (hpf), which increased in amplitude over time. Unlike rotation about an earth horizontal axis, rotation about an earth vertical axis at 0.25 Hz did not evoke eye movements. Moreover, vestibular-induced responses were absent in mutant cdh23 larvae and larvae lacking anterior otoliths. Conclusions Our results provide evidence for a functional vestibulo-oculomotor circuit in 72 hpf zebrafish larvae that relies upon sensory input from anterior/utricular otolith organs.
Smooth-pursuit eye movements transform 100 ms of visual motion into a rapid initiation of smooth eye movement followed by sustained accurate tracking. Both the mean and variation of the visually driven pursuit response can be accounted for by the combination of the mean tuning curves and the correlated noise within the sensory representation of visual motion in extrastriate visual area MT. Sensory-motor and motor circuits have both housekeeping and modulatory functions, implemented in the cerebellum and the smooth eye movement region of the frontal eye fields. The representation of pursuit is quite different in these two regions of the brain, but both regions seem to control pursuit directly with little or no noise added downstream. Finally, pursuit exhibits a number of voluntary characteristics that happen on short timescales. These features make pursuit an excellent exemplar for understanding the general properties of sensory-motor processing in the brain. PMID:20510853
Smooth pursuit eye movements transform 100 ms of visual motion into a rapid initiation of smooth eye movement followed by sustained accurate tracking. Both the mean and variation of the visually-driven pursuit response, can be accounted for by the combination of the mean tuning curves and the correlated noise within the sensory representation of visual motion in extrastriate visual area MT. Sensory-motor and motor circuits have both housekeeping and modulatory functions, implemented in the cerebellum and the smooth eye movement region of the frontal eye fields. The representation of pursuit is quite different in these two regions of the brain, but both regions seem to control pursuit directly with little or no noise added downstream. Finally, pursuit exhibits a number of voluntary characteristics that happen on short time scales. These features make pursuit an excellent exemplar for understanding the general properties of sensory-motor processing in the brain.
Measures of handedness have long been utilized as part of the neuropsychological assessment due to evidence that hand preference is related to cerebral dominance for language. Many lateral dominance examinations also include measurement of eye, ear, and\\/or foot preference, presumably for assessment of crossed laterality. Although a reliable relationship between crossed laterality and intelligence or achievement has not been demonstrated,
Stephen Sulzbacher; Jennifer Thomson; Jacqueline R. Farwell; Nancy R. Temkin; Ann Lu Holubkov
|This study investigates the hypothesis that it is mixed-dominance among left handers (i.e. left handedness and right eye and/or foot dominance), that is related to academic learning difficulties among such individuals, rather than the generally held notion that their difficulties stem from the fact that they are left handers in a "right handed…
Binocular non-dominant suppression (NDS) in the dorsal lateral geniculate nucleus (LGNd) of the cat was studied by recording from single neurons in the LGNd of anaesthetized, paralysed cats while stimulating the non-dominanteye with a moving light bar. The maintained discharge rate of LGNd neurons was varied by stimulating the dominanteye in various ways: by varying the size or
Gravity related behavior and the underlying neuronal networks are the most suitable model systems to study basic effects of altered gravitational input on the development of neuronal systems. A feature of sensory and motor systems is their susceptibility to modifications of their adequate physical and/or chemical stimuli during development. This discovery led to the formulation about critical periods, which defines the period of susceptibility during post-embryonal development. Critical periods can be determined by long-lasting modifications of the stimulus input for the gravity sensory system (GSS). Techniques include: (1) destruction of the gravity sense organ so that the gravity cannot be detected any longer and the central neuronal network of the GSS is deprived of gravity related information, (2) loading or deloading of parts of the body by weights or counterweights, respectively, which compensates for the gravitational pull, and (3) absence or augmentation of the gravitational environment per se by the exposure of organisms to microgravity during spaceflights or to hypergravity by centrifugation. Most data came from studies on compensatory eye or head movements in the clawed toad Xenopus laevis, the cichlid fish Oreochromis mossambicus, and crickets (Acheta domesticus, Gryllus bimaculatus). The responses are induced by a roll or pitch stimulation of the gravity sense organs, but are also affected by sensory inputs from proprioreceptors and eyes. The development of these compensatory eye and head responses reveals species-specific time courses. Based on experiments using spaceflights, centrifugation, lesion and loading or deloading, all species revealed a significant susceptibility to modifications of the gravity sensory input during development. Behavioral responses were depressed (Xenopus) or augmented (Xenopus, Oreochronis) by microgravity, and depressed by hypergravity except in crickets. In Acheta, however, the sensitivity of its position sensitive neuron PSI was reduced by microgravity. After termination of the period of modified gravity sensory input, all behavioral and physiological modifications disappeared, in some preparations such as the PSI of Acheta or the eye response in Xenopus, however, delayed after exposure to hypergravity. Irreversible modifications were rare; one example were malformations of the body of Xenopus tadpoles caused by lesion induced deprivation. Several periods of life such as the period of hatching or first appearance of gravity related reflexes revealed a specific sensitivity to altered gravity. Although all studies gave clear evidences for a basic sensitivity of developing GSSs to long-lasting modifications of the gravity sensory input, clear arguments for the existence of a critical period in the development of the sense of gravity are still missing. It has to take into consideration that during long-term exposures, adaptation processes take place which are guided by central physiological and genetically determined set points. The International Space Station (ISS) is the necessary platform of excellence if biological research is focussed on the analysis of long-term space effects on organisms. PMID:14631632
Under natural conditions, motor learning is instructed by sensory feedback. We have asked whether sensory signals that indicate motor errors are necessary to instruct learning or if the motor signals related to movements normally driven by sensory error signals would be sufficient. We measured eye movements in trained rhesus monkeys while employing electrical microstimulation of the floccular complex of the cerebellum and the smooth eye movement region of the frontal eye fields to alter ongoing pursuit eye movements. Repeated electrical stimulation at fixed times after the onset of target motion and pursuit failed to cause any learning that was retained beyond the time period used to instruct learning. Learning was not uncovered when the target was stabilized with respect to the moving eye to prevent competition between instructive signals created by electrical stimulation and visual image motion signals evoked when stimulation drove the eye away from the tracking target. We suggest that signals emanating from motor-related structures in the pursuit circuit do not instruct learning. Instead, instructive sensory error signals seem to be necessary. PMID:18579657
Heuer, Hilary W; Tokiyama, Stefanie; Lisberger, Stephen G
Under natural conditions, motor learning is instructed by sensory feedback. We have asked whether sensory signals that indicate motor errors are necessary to instruct learning or if the motor signals related to movements normally driven by sensory error signals would be sufficient. We measured eye movements in trained rhesus monkeys while employing electrical microstimulation of the floccular complex of the cerebellum and the smooth eye movement region of the frontal eye fields to alter ongoing pursuit eye movements. Repeated electrical stimulation at fixed times after the onset of target motion and pursuit failed to cause any learning that was retained beyond the time period used to instruct learning. Learning was not uncovered when the target was stabilized with respect to the moving eye to prevent competition between instructive signals created by electrical stimulation and visual image motion signals evoked when stimulation drove the eye away from the tracking target. We suggest that signals emanating from motor-related structures in the pursuit circuit do not instruct learning. Instead, instructive sensory error signals seem to be necessary.
Heuer, Hilary W.; Tokiyama, Stefanie; Lisberger, Stephen G.
Anticipatory movements are motor responses occurring before likely sensory events in contrast to reflexive actions. Anticipatory movements are necessary to compensate for delays present in sensory and motor systems. Smooth pursuit eye movements are often used as a paradigmatic example for the study of anticipation. However, the neural control of anticipatory pursuit is unknown. A previous study suggested that the supplementary eye fields (SEFs) could play a role in the guidance of smooth pursuit to predictable target motion. In this study, we favored anticipatory responses in monkeys by making the parameters of target motion highly predictable and electrically stimulated the SEF before and during this behavior. Stimulation sites were restricted to regions of the SEF where saccades could not be evoked at the same low currents. We found that electrical microstimulation in the SEF increased the velocity of anticipatory pursuit movements and decreased their latency. These effects will be referred to as anticipatory pursuit facilitation. The degree of facilitation was the largest if the stimulation train was delivered near the end of the fixation period, before the moment when anticipatory pursuit usually begins. No anticipatory smooth eye movements could be evoked during fixation without an expectation of target motion. These results suggest that the SEF pursuit area might be involved in the process of guiding anticipatory pursuit. PMID:15014104
Polysialic acid (PSA) is a unique carbohydrate composed of a linear homopolymer of ?-2,8 linked sialic acid, and is mainly attached to the fifth immunoglobulin-like domain of the neural cell adhesion molecule (NCAM) in vertebrate neural system. In the brain, PSA is exclusively synthesized by the two polysialyltransferases ST8SiaII (also known as STX) and ST8SiaIV (also known as PST). By modulating adhesive property of NCAM, PSA plays a critical role in several neural development processes such as cell migration, neurite outgrowth, axon pathfinding, synaptogenesis and activity-dependent plasticity. The expression of PSA is temporally and spatially regulated during neural development and a tight regulation of PSA expression is essential to its biological function. In mouse visual cortex, PSA is downregulated following eye opening and its decrease allows the maturation of GABAergic synapses and the opening of the critical period for ocular dominance plasticity. Relatively little is known about how PSA levels are regulated by sensory experience and neuronal activity. Here, we demonstrate that while both ST8SiaII and ST8SiaIV mRNA levels decrease around the time of eye opening in mouse visual cortex, only ST8SiaII mRNA level reduction is regulated by sensory experience. Using an organotypic culture system from mouse visual cortex, we further show that ST8SiaII gene expression is regulated by spiking activity and NMDA-mediated excitation. Further, we show that both ST8SiaII and ST8SiaIV mRNA levels are positively regulated by PKC-mediated signaling. Therefore, sensory experience-dependent ST8SiaII gene expression regulates PSA levels in postnatal visual cortex, thus acting as molecular link between visual activity and PSA expression. PMID:21957465
Use of arm and hand prostheses may be essential for many amputees to facilitate activities of daily life and interaction with society. A major drawback that reduces the use of prostheses, however, is the lack of sensibility. Current strategies for sensory feedback in commercially available prostheses are based on force and slip sensors in the mechanical hand for independent grasp control in an opening and closing function. Developing principles for providing conscious sensibility is discussed, including new techniques where hearing is used as substitution for sensation based on sense substitution. PMID:11599215
The biological effect of infrared radiation on the retina of the eye is discussed. Experimental data are presented on filter systems recommended for eye protective goggles which will reduce the level of high intensity thermal radiation. The filter systems...
... conjunctivitis with redness of the eye and mucoid debris on the eyelashes. Overview Pink eye (conjunctivitis) is ... Inflammatory causes such as chemicals, fumes, dust, and debris Allergies Injuries Oral genital contact with someone who ...
... the eye, or palpebral slant. Slanting and a fold of skin ( epicanthal fold ) are normal in people of Asian descent. Abnormal ... with Down syndrome often also have an epicanthal fold in the inner corner of the eye.
Peripheral neural mechanisms underlying the sensations of irritation, discomfort, and itch accompanying the eye allergic response have not been hitherto analyzed. We explored this question recording the changes in the electrical activity of corneoconjunctival sensory nerve fibers of the guinea pig after an ocular allergic challenge. Sensitization was produced by i.p. ovalbumin followed by repeated application in the eye of 10% ovalbumin on days 14 to 18. Blinking and tearing rate were measured. Spontaneous and stimulus-evoked (mechanical, thermal, chemical) impulse activity was recorded from mechanonociceptor, polymodal nociceptor and cold corneoscleral sensory afferent fibers. After a single (day 14) or repeated daily exposures to the allergen during the following 3 to 4days, tearing and blinking rate increased significantly. Also, sensitization was observed in mechanonociceptors (transient reduction of mechanical threshold only on day 14) and in polymodal nociceptors (sustained enhancement of the impulse response to acidic stimulation). In contrast, cold thermoreceptors showed a significant decrease in basal ongoing activity and in the response to cooling. Treatment with the TRPV1 and TRPA1 blockers capsazepine and HC-030031 reversed the augmented blinking. Only capsazepine attenuated tearing rate increase and sensitization of the polymodal nociceptors response to CO2. Capsazepine also prevented the decrease in cold thermoreceptor activity caused by the allergic challenge. We conclude that changes in nerve impulse activity accompanying the ocular allergic response, primarily mediated by activation of nociceptor's TRPV1 and to a lesser degree by activation of TRPA1 channels, explain the eye discomfort sensations accompanying allergic episodes. PMID:23867735
When assessing the roughness of textures, no single sensory modality universally dominates perception. Instead, the task and stimuli critically determine to what extent a given sense is favoured. We report a visuotactile texture assessment experiment, consisting of the speeded discrimination of roughened textile samples, in the presence of a congruent or an incongruent textile distractor. When discriminating between samples, visual assessment of textile roughness was modulated by incongruous tactile distractors, but not vice versa, even when visual distractors were more discriminable than tactile targets. This asymmetry in interference suggests that 'modality appropriateness' is not purely a function of the discriminative ability of a sensory modality, but that ecological validity may play a role in determining the more 'appropriate' sense for a given task. Results are discussed in relation to the claim that the assessment of textiles is more ecologically suited to touch than to vision. PMID:12679862
This document describes a method to solve the stereo correspondence using controlled eye (or camera) movements. These eye-movements essentially supply additional image-frames which can be used to constrain the stereo matching. Because the eye-movements ar...
Several Greek and Byzantine sovereigns are known in history by nicknames that are of ophthalmologic origin; the sobriquets derive from characteristics of their eyes or their actions in relation to the eyes. The first was Antigonos I Monophthalmus (the One-eyed), who was the most eminent successor of Alexander the Great and Sovereign of Eastern Mediterranean Asia. He obtained his nickname
|Johns Hopkins researchers at the Wilmer Eye Institute have discovered what appears to be the first human gene mutation that causes extreme farsightedness. The researchers report that nanophthalmos, Greek for "dwarf eye," is a rare, potentially blinding disorder caused by an alteration in a gene called MFRP that helps control eye growth and…
Lateral dominance, as determined by tests of eye, hand, and foot preference, was investigated as a factor in motor skill acquisition. 3 groups of Ss, classified as right dominant, crossed dominant, or mixed dominant, practiced 3 motor skills for 18 practice sessions. All 3 groups showed significant learning of the 3 motor skills; however, there was no significant difference among the groups in performance or in rate of improvement on the skills. It was concluded that Ss displaying different dominance patterns, as defined in this study, appear equally capable of learning selected new motor skills. PMID:23947378
Decisions about what food to buy, eat and serve for one’s family and friends are complex and influenced by many factors other than sensory quality. It is widely agreed that while taste and other sensory qualities are very important, they only partially account for consumers’ food related behaviours. This paper considers the role of several other factors: convenience, price, production
This paper examines conditions that have variously been called sensory integration disorder, sensory processing disorder,\\u000a and sensory modulation disorder (SID\\/SPD\\/SMD). As these conditions lack readily and consistently agreed-upon operational definitions,\\u000a there has been confusion as to how these disorders are conceptualized. Rather than addressing various diagnostic controversies,\\u000a we will instead focus upon explaining the symptoms that are believed to characterize
Leonard F. Koziol; Deborah Ely Budding; Dana Chidekel
We perceive the three-dimensional (3D) environment that surrounds us with deceptive effortlessness. In fact, we are far from comprehending how the visual system provides us with this stable perception of the (3D) world around us. This thesis will focus on the interplay between visual perception of depth and its closely related action system, eye movements in depth. The human visual system is comprised of a sensory (input) and an output (motor) system. Processed information from the sensory system can result in two explicit measurable response types: conscious visual perception and ocular motor behavior. It is still a matter of debate whether conscious visual perception and action (including hand- and arm-movements) use the same information or whether the visual system has separate channels processing information for perception and action. In this thesis, we study (1) if separate channels, one for eye movements and one for conscious visual perception, indeed exist, and (2) if so, if there is a direct input from the perceptual pathway to the motor pathway. Assuming that either eye movements and conscious visual perception are based on information from a common source (a negative answer to issue 1) or perception can directly influence, or guide, eye movements (an affirmative answer to research question 2), (eye) movements reflect our conscious visual perception. If so, eye movements could provide us with an alternative method to probe our conscious visual perception, making explicit perceptual reports superfluous. In this thesis we focus on depth perception and the two types of eye movements that are closest related to depth perception, namely vergence (an eye movement that gets a certain depth plane into focus) and saccades (a rapid eye movement to change gaze direction). Over the last 20 years it has been shown that depth perception is based on a weighted combination of depth cues available such as linear perspective, occlusion and binocular disparity. How eye movements are planned, however, is still unclear. Several studies have reported that eye movements are, to varying degrees, correlated with perception and thus concluded that perception guides eye movements. However, in most of these studies depth perception was correlated to the depth cues and a clear distinction between cues and perception could not be made. A way to make a dissociation between cues and perception, is to make use of depth reversal illusions: stimuli that can induce multiple equally likely depth interpretations while the stimulus cues remain the same. That means that perception can alternate, while cues remain constant leading to a dissociation between perception and cues. In several different studies we show that in the case of vergence, eye movements are planned based on depth cues (mainly disparity) and are uncorrelated to perception. In the case of saccades, we show that the direction of saccades is highly correlated to perception, but seems to be subserved by a separate system combining cues using very similar weights as for perception.
Orienting visual attention is closely linked to the oculomotor system. For example, a shift of attention is usually followed by a saccadic eye movement and can be revealed by micro saccades. Recently we reported a novel role of another type of eye movement, namely eye vergence, in orienting visual attention. Shifts in visuospatial attention are characterized by the response modulation to a selected target. However, unlike (micro-) saccades, eye vergence movements do not carry spatial information (except for depth) and are thus not specific to a particular visual location. To further understand the role of eye vergence in visual attention, we tested subjects with different perceptual styles. Perceptual style refers to the characteristic way individuals perceive environmental stimuli, and is characterized by a spatial difference (local vs. global) in perceptual processing. We tested field independent (local; FI) and field dependent (global; FD) observers in a cue/no-cue task and a matching task. We found that FI observers responded faster and had stronger modulation in eye vergence in both tasks than FD subjects. The results may suggest that eye vergence modulation may relate to the trade-off between the size of spatial region covered by attention and the processing efficiency of sensory information. Alternatively, vergence modulation may have a role in the switch in cortical state to prepare the visual system for new incoming sensory information. In conclusion, vergence eye movements may be added to the growing list of functions of fixational eye movements in visual perception. However, further studies are needed to elucidate its role. PMID:24069140
Solé Puig, Maria; Puigcerver, Laura; Aznar-Casanova, J Antonio; Supèr, Hans
Orienting visual attention is closely linked to the oculomotor system. For example, a shift of attention is usually followed by a saccadic eye movement and can be revealed by micro saccades. Recently we reported a novel role of another type of eye movement, namely eye vergence, in orienting visual attention. Shifts in visuospatial attention are characterized by the response modulation to a selected target. However, unlike (micro-) saccades, eye vergence movements do not carry spatial information (except for depth) and are thus not specific to a particular visual location. To further understand the role of eye vergence in visual attention, we tested subjects with different perceptual styles. Perceptual style refers to the characteristic way individuals perceive environmental stimuli, and is characterized by a spatial difference (local vs. global) in perceptual processing. We tested field independent (local; FI) and field dependent (global; FD) observers in a cue/no-cue task and a matching task. We found that FI observers responded faster and had stronger modulation in eye vergence in both tasks than FD subjects. The results may suggest that eye vergence modulation may relate to the trade-off between the size of spatial region covered by attention and the processing efficiency of sensory information. Alternatively, vergence modulation may have a role in the switch in cortical state to prepare the visual system for new incoming sensory information. In conclusion, vergence eye movements may be added to the growing list of functions of fixational eye movements in visual perception. However, further studies are needed to elucidate its role.
Sole Puig, Maria; Puigcerver, Laura; Aznar-Casanova, J. Antonio; Super, Hans
Under many conditions, humans display a robust tendency to rely more on visual information than on other forms of sensory\\u000a information. Colavita (1974) illustrated this visual dominance effect by showing that naive observers typically fail to respond\\u000a to clearly suprathreshold tones if these are presented simultaneously with a visual target flash. In the present study, we\\u000a demonstrate that visual dominance
Scott Sinnett; Charles Spence; Salvador Soto-Faraco
Based on the premise that perception is a continual series of simple hypotheses about the external world which are built up and selected by sensory experiences, this book explores in detail some of the major findings in perception and speculates about interconnections between sensory experiences, brain function, perception, and language and…
Temporal dominance of sensations (TDS) and time intensity (TI) were used to characterize specific organoleptic properties of six beverage products. Results from these two sensory techniques were compared by using three different statistical approaches. Firstly, both TI and TDS results were analysed by parametric modelling, to determine key parameters of each individual curve. Average parameters over judges and repetitions were
Fanny M. Le Révérend; Claire Hidrio; Angela Fernandes; Victoire Aubry
Electromyographic examination and studies of motor and sensory conduction velocities were performed in 11 patients with a presumptive diagnosis of olivopontocerebellar atrophy with autosomal dominant transmission. Peripheral nervous system involvement was shown in eight. In two patients with early onset of disease, electrophysiological alterations clearly pointed to severe axonal degeneration, whereas in six they were compatible with slight demyelination.
L. Carenini; G. Finocchiaro; S. Di Donato; A. Visciani; S. Negri
Extracellular purines play multiple roles in a variety of sensory systems acting as neural signalling and humoral factors via purinoceptors. For example, ATP and adenosine have a neurosignalling role in autonomic sensory–motor reflexes, mechanoreception and chemoreception mediated via vagus nerve afferents, and in nociception. Purinergic neuromodulation of vision via adenosine in the retina is well established and there is mounting
Sensory modulation disorder (SMD) is a severe inability to regulate responses to everyday sensory stimulation to which most people easily adapt. It is estimated to affect 5% to 16% of the general population of children. Although heterogeneity is seen in the presentation clinically, previous research has not empirically investigated whether the clinical heterogeneity of SMD can be classified into subtypes.
Katherine James; Lucy Jane Miller; Roseann Schaaf; Darci M. Nielsen; Sarah A. Schoen
Halobacterium salinarum sensory rhodopsin I (HsSRI), a dual receptor regulating both negative and positive phototaxis in haloarchaea, transmits light signals through changes in protein-protein interactions with its transducer, halobacterial transducer protein I (HtrI). Haloarchaea also have another sensor pigment, sensory rhodopsin II (SRII), which functions as a receptor regulating negative phototaxis. Compared with HsSRI, the signal relay mechanism of SRII is well characterized because SRII from Natronomonus pharaonis (NpSRII) is much more stable than HsSRI and HsSRII, especially in dilute salt solutions and is much more resistant to detergents. Two genes encoding SRI homologs were identified from the genome sequence of the eubacterium Salinibacter ruber. Those sequences are distantly related to HsSRI (?40% identity) and contain most of the amino acid residues identified as necessary for its function. To determine whether those genes encode functional protein(s), we cloned and expressed them in Escherichia coli. One of them (SrSRI) was expressed well as a recombinant protein having all-trans retinal as a chromophore. UV-Vis, low-temperature UV-Vis, pH-titration, and flash photolysis experiments revealed that the photochemical properties of SrSRI are similar to those of HsSRI. In addition to the expression system, the high stability of SrSRI makes it possible to prepare large amounts of protein and enables studies of mutant proteins that will allow new approaches to investigate the photosignaling process of SRI-HtrI.
This booklet is designed to help persons who have elderly family members or who work with older adults understand and help compensate for the sensory changes that occur in later life. It contains sections on vision, hearing, taste and smell, and touch. Discussed in the section on vision are the following: common age-related changes, eye diseases…
This pilot study explored the relationship between sensory defen- siveness and anxiety, as well as the impact of a sensory integration treatment protocol on normal adults. Fifteen adult subjects identified as having sensory defensiveness completed the Adult Sensory Questionnaire (ASQ), Adult Sensory Interview (ADULT-SI), and Beck Anxiety Inventory (BAI) at pre-test and post-test intervals to measure sensory defensiveness and anxiety.
Photoreception is one of the most primitive sensory functions in metazoans. Despite the diversity of forms and components of metazoan eyes, many studies have demonstrated the existence of a common cellular and molecular basis for their development. Genes like pax6, sine oculis, eyes absent, dachshund, otx, Rx and atonal are known to be associated with the specification and development of the eyes. In planarians, sine oculis, eyes absent and otxA play an essential role during the formation of the eye after decapitation, whereas pax6, considered by many authors as a master control gene for eye formation, does not seem to be involved in adult eye regeneration. Whether this is a peculiarity of adult planarians or, on the contrary, is also found in embryogenesis remains unknown. Herein, we characterize embryonic eye development in the planarian species Schmidtea polychroa using histological sections and molecular markers. Additionally, we analyse the expression pattern of the pax6-sine oculis-eyes absent-dachshund network, and the genes Rx, otxA, otxB and atonal. We demonstrate that eye formation in planarian embryos shows great similarities to adult eye regeneration, both at the cellular and molecular level. We thus conclude that planarian eyes exhibit divergent molecular patterning mechanisms compared to the prototypic ancestral metazoan eye. PMID:22327190
Martín-Durán, José María; Monjo, Francisco; Romero, Rafael
Dyslexic children, besides difficulties in mastering literacy, also show poor postural control that might be related to how sensory cues coming from different sensory channels are integrated into proper motor activity. Therefore, the aim of this study was to examine the relationship between sensory information and body sway, with visual and somatosensory information manipulated independent and concurrently, in dyslexic children. Thirty dyslexic and 30 non-dyslexic children were asked to stand as still as possible inside of a moving room either with eyes closed or open and either lightly touching a moveable surface or not for 60 seconds under five experimental conditions: (1) no vision and no touch; (2) moving room; (3) moving bar; (4) moving room and stationary touch; and (5) stationary room and moving bar. Body sway magnitude and the relationship between room/bar movement and body sway were examined. Results showed that dyslexic children swayed more than non-dyslexic children in all sensory condition. Moreover, in those trials with conflicting vision and touch manipulation, dyslexic children swayed less coherent with the stimulus manipulation compared to non-dyslexic children. Finally, dyslexic children showed higher body sway variability and applied higher force while touching the bar compared to non-dyslexic children. Based upon these results, we can suggest that dyslexic children are able to use visual and somatosensory information to control their posture and use the same underlying neural control processes as non-dyslexic children. However, dyslexic children show poorer performance and more variability while relating visual and somatosensory information and motor action even during a task that does not require an active cognitive and motor involvement. Further, in sensory conflict conditions, dyslexic children showed less coherent and more variable body sway. These results suggest that dyslexic children have difficulties in multisensory integration because they may suffer from integrating sensory cues coming from multiple sources. PMID:23977346
Viana, André R; Razuk, Milena; de Freitas, Paulo B; Barela, José A
Visuomotor coordination requires both the accurate alignment of spatial information from different sensory streams and the ability to convert these sensory signals into accurate motor commands. Both of these processes are highly plastic, as illustrated by the rapid adaptation of goal-directed movements following exposure to shifted visual feedback. Although visual-shift adaptation is a widely used model of sensorimotor learning, the multi-faceted adaptive response is typically poorly quantified. We present an approach to quantitatively characterizing both sensory and task-dependent components of adaptation. Sensory after-effects are quantified with “alignment tests” that provide a localized, two-dimensional measure of sensory recalibration. These sensory effects obey a precise form of “additivity”, in which the shift in sensory alignment between vision and the right hand is equal to the vector sum of the shifts between vision and the left hand and between the right and left hands. This additivity holds at the exposure location and at a second generalization location. These results support a component transformation model of sensory coordination, in which eye-hand and hand-hand alignment relies on a sequence of shared sensory transformations. We also ask how these sensory effects compare to the after-effects measured in target reaching and tracking tasks. We find that the after-effect depends on both the task performed during feedback-shift exposure and on the testing task. The results suggest the presence of both a general sensory recalibration and task-dependent sensorimotor effect. The task-dependent effect is observed in highly stereotyped reaching movements, but not in the more variable tracking task.
The evolution of dominance has been subject to intensive debate since Fisher first argued that modifiers would be selected for if they made wild-type alleles more dominant over mutant alleles. An alternative explanation, put forward by Wright, is that the commonly observed dominance of wild-type alleles is simply a physiological consequence of metabolic pathways. Wright’s explanation has gained support over
In Canada 30,000 people are registered as blind; in one third of these, blindness might have been avoided. Prevention is the key to reducing the number of eye injuries and blind eyes. The role of the family physician in early identification of treatable conditions and in the education of patients is discussed, but responsibility for prevention belongs to all physicians. The success of prevention is seen in the great reduction in eye injuries in industry and sports since eye protectors have been commonly used. However, many dangers to the eyes are either not recognized or are not taken seriously enough. This paper discusses some of the common causes of serious eye injuries in the home, in sports and in industry. Imagesp464-aFig. 1Fig. 2Fig. 3Fig. 4
Attention mediates access of sensory events to higher cognitive systems and can be driven by either top-down voluntary mechanisms or in a bottom-up, reflexive fashion by the sensory properties of a stimulus. The exact mechanisms underlying these different modes of attention are controversial, but both types of attention appear to be tightly coupled to the systems used for the control of eye-movements. Indeed, recent data indicates that patients with opthalmoplegia (paralysis of the eyes) have difficulty voluntarily attending to locations to which saccades cannot be made (Craighero, Carta, & Fadiga, 2001) and experimentally induced opthalmoplegia disrupts voluntary attention in normal participants. However, the extent to which reflexive attention is mediated by the ability to make eye-movements in normal participants remains unclear. Here, we address this issue by investigating the effect of an experimentally induced opthalmoplegia on voluntary and reflexive attentional orienting during visual search. We observed that abducting the eye into the temporal hemifield elicited deficits of both voluntary and reflexive attention for targets that appeared beyond the oculomotor range. This result confirms the link between oculomotor control and voluntary attention observed in opthalmoplegic patients and demonstrates for the first time that reflexive attention is mediated by the ability to make eye-movements in normal participants. PMID:20036265
Smith, Daniel T; Ball, Keira; Ellison, Amanda; Schenk, Thomas
According to ancient Greek mythology, Argus, the hundred-eyed guardian of the goddess Hera, alone defeated a whole army of Cyclopes, one-eyed giants. The mythological power of many eyes becomes a reality in this book, after seeing the capabilities of current multi camera networks. The preceding chapters have communi- cated the excitement around this newly formed field. Multi-camera networks are new
Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the timing mechanisms and sensory physiology of mating related signals. PMID:23460896
Streinzer, Martin; Brockmann, Axel; Nagaraja, Narayanappa; Spaethe, Johannes
Dry eye is one of the most common complications after laser-assisted in situ keratomileusis (LASIK). The clinical signs of post-LASIK dry eye include positive vital staining of ocular surface, decreased tear film breakup time and Schirmer test, reduced corneal sensitivity, and decreased functional visual acuity. The symptoms and signs last at least 1 month after LASIK. Although the mechanisms for developing post-LASIK dry eye are not completely understood, loss of corneal innervation by flap-making may affect the reflex loops of the corneal-lacrimal gland, corneal-blinking, and blinking-meibomian gland, and blinking-meibomian gland, resulting in decreased aqueous and lipid tear secretion and mucin expression. As LASIK enhancement by flap-lifting induces less dry eye symptoms and signs than first surgery, it is suggested that other factors rather than loss of neurotrophic effect may be involved in the mechanisms of post-LASIK dry eye. The treatments of dry eye include artificial tears, topical cyclosporine, hot compress, punctal plugs, and autologous serum eye drops. For patients with severe preoperative dry eye, a combination of punctal plugs and serum eye drops is required to be used before surgery. PMID:17540125
Feeding is essential for survival, whereas withdrawal and escape reactions are fundamentally protective. These critical behaviors can compete for an animal's resources when an acutely painful stimulus affects the animal during feeding. One solution to the feeding-withdrawal conflict is to optimize feeding by suppressing pain. We examined whether rats continue to feed when challenged with a painful stimulus. During feeding, motor withdrawal responses to noxious paw heat either did not occur or were greatly delayed. To investigate the neural basis of sensory suppression accompanying feeding, we recorded from brainstem pain-modulatory neurons involved in the descending control of pain transmission. During feeding, pain-facilitatory ON cells were inhibited and pain-inhibitory OFF cells were excited. When a nonpainful somatosensory stimulus preactivated ON cells and preinhibited OFF cells, rats interrupted eating to react to painful stimuli. Inactivation of the brainstem region containing ON and OFF cells also blocked pain suppression during eating, demonstrating that brainstem pain-modulatory neurons suppress motor reactions to external stimulation during homeostatic behaviors.
Contents: Minimum necessary eye protection guidelines(Summary); Eye hazards for emergency response and disaster recovery; Four points to eye safety; Type of eye protection; Eye safety for prescription lens wearers; First aid for eye injuries and Informati...
The report summarizes research in the sensory structure and related selected organ system of ticks, mites and fly larva. Scanning and transmission electron microscopy are utilized. A list of publications is given with an abstract for each journal publicat...
The goal of this project was to explore the sensory mechanisms which control the expression of bioluminescence in the marine bacterium Vibrio harveyi. Genetic methods were used to discover the genes which encode functions for the production of extracellul...
In the diagnosis of functional weakness and sensory disturbance, positive physical signs are as important as absence of signs of disease. Motor signs, particularly Hoover's sign, are more reliable than sensory signs, but none should be used in isolation and must be interpreted in the overall context of the presentation. It should be borne in mind that a patient may have both a functional and an organic disorder.
Opinion statement No current disease-modifying treatments have been shown definitively in randomized clinical trials to reduce or reverse diabetic\\u000a sensory polyneuropathy (DSP). It is increasingly recognized that individuals with “prediabetes” or impaired glucose regulation\\u000a can already have a “small-fiber” neuropathy, or mild DSP, in which sensory axons of both small and larger diameter are damaged.\\u000a Small-fiber neuropathy is frequently associated with
Experiments are presented in support of the hypothesis that acetylcholine functions as a sensory transmitter in the lobster nervous system. 1. Several different peripheral sensory structures incorporate radioactive choline into acetylcholine. The preparation most enriched in sensory as opposed to other nervous elements (the antennular sense organs of the distal outer flagellum) does not incorporate significant amounts of glutamate, tyrosine or tryptophan into any of the other major transmitter candidates. 2. There is a parallel between the distribution of the enzyme choline acetyltransferase and the proportion of sensory fibres in nervous tissue from many parts of the lobster nervous system. 3. Isolated sensory axons contain at least 500 times as much choline acetyltransferase per cm of axon as do efferent excitatory and inhibitory fibres. 4. Abdominal ganglia and root stumps show a decline in the rate of incorporation of choline into acetylcholine 2 to 8 weeks after severing the first and second roots bilaterally (leaving the connectives and third roots intact). Extracts of the root stumps exhibit a significantly lower level of choline acetyltransferase 2 weeks after this operation. 5. Curare and atropine partially block an identified sensory synapse in the lobster abdominal ganglion. ImagesText-fig. 4Text-fig. 5Plate 1
Barker, David L.; Herbert, Edward; Hildebrand, John G.; Kravitz, Edward A.
A variety of sensory stimuli (e.g., visual, auditory, and thermal) are known to induce rapid eye movement (REM) sleep in mammals. Studies have examined the induction of REM sleep in albino rats by light-to-dark transitions, a phenomenon referred to as REM sleep triggering. Recent research has demonstrated that aspiration lesions of the superior colliculus (SC) and pretectal area attenuated REM
Ann M. Miller; Robert B. Miller; William H. Obermeyer; Mary Behan; Ruth M. Benca
A quantitative descriptive analysis was developed to characterize the sensory quality of a set of 12 organic and conventional tomato juices sold in Spanish and Italian markets. The volatile compounds of tomato juices were also studied. Twelve sensory descriptors, selected by a trained panel, evaluated the sensory profile of the samples. Some tomato juices were characterized by dominant positive notes typical of tomatoes (tomato paste, vegetable notes), whereas others by negative sensory attributes (off-flavors, high intensity of acidity, and sweetness). The volatile pattern of the samples, studied by SPME/GC-MS, was correlated with the sensory results: basically, organic tomato juices were characterized by vegetable notes and higher volatile compounds than conventional samples, regardless of their geographical origin. Conventional tomato juices were grouped in a closer cluster, whereas organic tomato juices were more diversified. Moreover, "defective" samples showed higher amounts of 3-methyl-1-butanol. PMID:23320944
The combination of the cornea of an eye and a camera viewing the eye form a catadioptric (mirror + lens) imaging system with a very wide field of view. We present a detailed analysis of the characteristics of this corneal imaging system. Anatomical studies have shown that the shape of a normal cornea (without major defects) can be approximated with
Students design and build prototypes for protective eyewear. They choose different activities or sports that require protective eyewear and design a device for that particular use. Students learn about the many ways in which the eyes can be damaged and how engineers incorporate different features and materials into eyewear designs to best protect the eyes.
During eye development, cell death interplays dynamically with events of differentiation to achieve the remarkably patterned structure of the fly compound eye. Mutations in genes that affect the normal developmental process can lead to excessive death of progenitor cells, or, alternatively, to the differentiation of supernumerary neurons, pigment and cone cells due to survival of cells that would normally be
The eye in a triangle that appears on the reverse of the Great Seal of the United States was called the Eye of Providence by the designers of the seal. The origins of this symbol which appeared in the last half of the seventeenth century are documented nowhere. However, consideration of analogous symbols and seventeenth century writers makes it clear
This paper addresses the accuracy problem of an eye gaze tracking system. We first analyze the technical barrier for a gaze tracking system to achieve desired accuracy, and then propose a subpixel tracking method to break the barrier. We present new algorithms for detecting the inner eye corner and the center of an iris in subpixel accuracy, and we apply
This study examines the validity of the Sensory Balance Test (SBT), which uses the technology of computerized dynamic posturography, to screen children for sensory processing impairments. Twenty typically developing children and 20 children with sensory processing impairments were administered the SBT under six different sensory conditions. The results show that children's sensory balance composite scores (SBT summary score) are associated
Shu-Yuan Hu; Jim Hinojosa; Ping-Yen Chiang; Cheng-Shiun Leu
These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Pro...
Summary The texture of steam-cooked potatoes from ten cultivars was sensory evaluated after two, four and nine months storage for\\u000a three consecutive years. The sensory data were analyzed using Principal Component Analysis (PCA) and regression analysis.\\u000a PCA revealed that the first two principal components explained 95% or more of the variance between the data. The first principal\\u000a component was dominated by
J. Trinette Van Marle; Ria van der Vuurst de Vries; E. Clare Wilkinson; Dogan Yuksel
The use of Helmet-Mounted Trackers and Displays (HMT\\/Ds) is becoming widespread for air-to-air, within visual range target acquisition; however these systems have physiological limitations. The Air Force Research Laboratory Helmet- Mounted Sensory Technologies (HMST) program is currently studying the use of eye trackers to cue High Off Boresight Angle missiles. The development and implementation of an eye tracker can eliminate
Single neurons in cortical area LIP are known to carry information relevant to both sensory and value-based decisions that are reported by eye movements. It is not known, however, how sensory and value information are combined in LIP when individual decisions must be based on a combination of these variables. To investigate this issue, we conducted behavioral and electrophysiological experiments in rhesus monkeys during performance of a two-alternative, forced-choice discrimination of motion direction (sensory component). Monkeys reported each decision by making an eye movement to one of two visual targets associated with the two possible directions of motion. We introduced choice biases to the monkeys' decision process (value component) by randomly interleaving balanced reward conditions (equal reward value for the two choices) with unbalanced conditions (one alternative worth twice as much as the other). The monkeys' behavior, as well as that of most LIP neurons, reflected the influence of all relevant variables: the strength of the sensory information, the value of the target in the neuron's response field, and the value of the target outside the response field. Overall, detailed analysis and computer simulation reveal that our data are consistent with a two-stage drift diffusion model proposed by Diederich and Bussmeyer  for the effect of payoffs in the context of sensory discrimination tasks. Initial processing of payoff information strongly influences the starting point for the accumulation of sensory evidence, while exerting little if any effect on the rate of accumulation of sensory evidence.
Rorie, Alan E.; Gao, Juan; McClelland, James L.; Newsome, William T.
Movement control requires continuous and reciprocal exchange of information between activities of motor areas involved in the task program execution and those elaborating proprioceptive sensory information. Our aim was to investigate the sensorimotor interactions in the region dedicated to hand control in healthy humans, focusing onto primary sensory and motor cortices, by selecting the time window at very early latencies. Through magnetoencephalographic recordings, we obtained a simultaneous assessment of sensory cortex activity modulation due to movement and of motor cortex activity modulation due to sensory stimulation, by eliciting a galvanic stimulation to the nerve (the median nerve) innervating a muscle (the opponens pollicis), at rest or during voluntary contraction. The primary sensory and motor cortices activities were investigated respectively through excitability in response to sensory stimulation and the cortico-muscular coherence. The task was performed bilaterally. A clear reduction of the cortico-muscular coherence was found in the short time window following stimuli (between around 150-450 ms). In the same time period, the motor control of isometric contraction was preserved. This could suggest that cortical component of voluntary movement control was transiently mediated by neuronal firing rate tuning more than by cortico-muscular synchronization. In addition to the known primary sensory cortex inhibition due to movement, a more evident reduction was found for the component known to include a contribution from primary motor areas. Gating effects were lower in the dominant left hemisphere, suggesting that sensorimotor areas dominant for hand control benefit of narrowing down gating effects. PMID:16713107
Tecchio, F; Zappasodi, F; Melgari, J M; Porcaro, C; Cassetta, E; Rossini, P M
The effectiveness of eye care service delivery is often dependant on how the different stakeholders are aligned. These stakeholders range from the ministries of health who have the capacity to grant government subsidies for eye care, down to the primary healthcare workers who can be enrolled to screen for basic eye diseases. Advocacy is a tool that can help service providers draw the attention of key stakeholders to a particular area of concern. By enlisting the support, endorsement and participation of a wider circle of players, advocacy can help to improve the penetration and effectiveness of the services provided. There are several factors in the external environmental that influence the eye care services - such as the availability of trained manpower, supply of eye care consumables, government rules and regulations. There are several instances where successful advocacy has helped to create an enabling environment for eye care service delivery. Providing eye care services in developing countries requires the support - either for direct patient care or for support services such as producing trained manpower or for research and dissemination. Such support, in the form of financial or other resources, can be garnered through advocacy. PMID:22944745
Eye movements help capture optic-flow information necessary to perceive visually our self motion. Visual and vestibular systems control compensatory eye movements that serve to stabilize the retinal images we capture. We examined the role that these eye movements may play in generating visual illusions of self motion (or vection). Observers viewed radially expanding optic-flow displays while performing lateral translational head oscillations at 1 Hz. Simulated viewpoint changes in these displays were synchronized with head movements, either in an ipsilateral (minimal sensory conflict) or a contralateral (high sensory conflict) direction. In control conditions, the observer viewed purely radial displays. Vection-onset latency and overall vection strength ratings were recorded, as well as horizontal eye movements. Vection onsets and strength ratings were significantly greater when the observer's head movements were incorporated into the visual displays. However, vection strength ratings were very similar for both ipsilateral and contralateral active display oscillation. Surprisingly, the non-ecological contralateral viewpoint oscillation actually induced vection earlier, despite the relatively small eye-in-head rotations coordinating gaze in these conditions. Our results support the view that compensatory eye movements are controlled through cooperative visual and vestibular interactions, and show that linear vection is highly robust against large sensory conflicts. PMID:20041234
This study measured test-retest reliabilities and interrelationships of four common measures of lateral dominance: dowel balancing, peg placement, grip strength, and conjugate lateral eye movement. Moderate reliabilities for all measures except grip strength were obtained. Subjects' sex may be an important reliability variable. Correlations among…
|This study measured test-retest reliabilities and interrelationships of four common measures of lateral dominance: dowel balancing, peg placement, grip strength, and conjugate lateral eye movement. Moderate reliabilities for all measures except grip strength were obtained. Subjects' sex may be an important reliability variable. Correlations among…
Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems using iris recognition are among the most secure biometric systems. PMID:22220469
A review of all penetrating eye injuries treated at the Manchester Royal Eye Hospital over four years (1 January 1982-31 December 1985) was undertaken. A total of 202 penetrating eye injuries were seen of which 68 (34%) were in children under the age of 15 years. Airgun, dart, and knife injuries accounted for 28 (41%) of the injuries. Thirty seven patients (54%) achieved a good visual result (6/12 or better) and eight (12%) had enucleations. The period of inpatient treatment ranged from two to 18 days. From the analysis of the activities at the time of the injury, many of the injuries can be considered to be preventable.
Our group has been involved in the design and synthesis of ultra-sensitive fluorescence sensory materials for the detection of 2,4,6 trinitrotoluene (TNT) and 2,4 dinitrotoluene (DNT). These schemes make use of a novel energy migration mechanisms to amplify the fluorescence response and have led to systems capable of rapid detection of these analytes at sub part-per-billion levels. In an effort to optimize the amplification and specificity, we have examined the nature of energy migration in our polymers systems because it is inherent in achieving amplification. polarization measurements and energy transfer studies between polymers were conducted in order to evaluate and maximize energy migration and hence TNT sensory response. The correlation of photo physical properties with molecular structure guided the synthesis of novel polymers with more discriminant optical responses. These synthetic efforts have yielded a library of sensory polymers with varying sensitivities to different analytes.
Rose, Aimee; Lugmair, Claus G.; Miao, Yi-Jun; Kim, Jinsang; Levitsky, Igor A.; Williams, Vance E.; Swager, Timothy M.
As apex predators, chondrichthyans, or cartilaginous fishes, hold an important position within a range of aquatic ecosystems and influence the balance between species' abundance and biodiversity. Having been in existence for over 400 million years and representing the earliest stages of the evolution of jawed vertebrates, this group also covers a diverse range of eco-morphotypes, occupying both marine and freshwater habitats. The class Chondrichthyes is divided into two subclasses: the Elasmobranchii (sharks, skates, and rays) and the Holocephali (elephant sharks and chimaeras). However, many of their life history traits, such as low fecundity, the production of small numbers of highly precocious young, slow growth rates, and late maturity, make them highly susceptible to human exploitation. To mitigate the negative effects of human impacts, it is important that we understand the sensory strategies that elasmobranchs use for navigating within their environment, forming reproductive aggregations, feeding, and even communicating. One approach to investigate the sensory bases of their behavior is to examine the peripheral sense organs mediating vision, olfaction, gustation, lateral line, electroreception, and audition in a large range of species in order to identify specific adaptations, the range of sensitivity thresholds, and the compromise between sensory spatial resolution and sensitivity. In addition, we can quantitatively assess the convergence of sensory input to the central nervous system and the relative importance of different sensory modalities. Using a comparative approach and often a combination of anatomical, electrophysiological, and molecular techniques, significant variation has been identified in the spatial and chromatic sampling of the photoreceptors in the eye, the surface area and the number of olfactory lamellae within the nasal cavity, the level of gustatory sampling within the oral cavity, the type and innervation of neuromasts of the lateral line system, the distribution of electroreceptive pores over the head, and the morphology of the inner ear. These results are presented in the context of predictions of sensory capabilities for species living in a range of ecological niches, what further research is needed, and how this sensory input may be a predictor of behavior. PMID:22986825
Why is allergic eye disease, and vernal keratoconjunctivitis (VKC) in particular, a problem for eye workers and patients in hot climates? A large number of children are affected Over a quarter of 2,250 children seen at a tertiary referral paediatric eye clinic in East Africa had vernal keratoconjunctivitis. Even more came flocking to screening clinics complaining of itchy eyes. This
Multimodal biometrics use more than one means of biometric identification to achieve higher recognition accuracy, since sometimes a unimodal biometric is not good enough used to do identification and classification. In this paper, we proposed a multimodal eye recognition system, which can obtain both iris and sclera patterns from one color eye image. Gabor filter and 1-D Log-Gabor filter algorithms have been applied as the iris recognition algorithms. In sclera recognition, we introduced automatic sclera segmentation, sclera pattern enhancement, sclera pattern template generation, and sclera pattern matching. We applied kernelbased matching score fusion to improve the performance of the eye recognition system. The experimental results show that the proposed eye recognition method can achieve better performance compared to unimodal biometric identification, and the accuracy of our proposed kernel-based matching score fusion method is higher than two classic linear matching score fusion methods: Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA).
Zhou, Zhi; Du, Yingzi; Thomas, N. L.; Delp, Edward J., III
Home » Photos, Images, and Videos » Search Results Photos, Images, and Videos Search Results Instructions for Downloading Photographs and Images Description: A color illustration of the eye highlighting the cornea, pupil and ...
... older could improve their vision through proper refractive correction. More than 3.3 million Americans aged 40 ... the National Eye Institute showed that proper refractive correction could improve vision among 11 million Americans aged ...
Purpose. To evaluate quantitatively the pattern of retinal nerve fiber layer (RNFL) damage in eyes with normal-tension glaucoma (NTG) with hemifield dominant visual field defects using scanning laser polarimetry. Methods. Prospectively, 40 consecutive eyes from 40 patients with NTG and hemifield defect based on the findings of examination using the Humphrey Field Analyzer underwent RNFL thickness measurements. Twenty normal eyes
Michael S. Kook; Sang-un Lee; Kyung-rim Sung; Hungwon Tchah; Soon-tae Kim; Kyung-rhee Kim; Weechang Kang
Visual experience during a critical period early in postnatal development can change connections within mammalian visual cortex. In a kitten at the peak of the critical period (?P28–42), brief monocular deprivation can lead to complete dominance by the open eye, an ocular dominance shift. This process is driven by activity from the eyes, and depends on N-methyl-D-aspartate (NMDA) receptor activation.
Qinghua Ji; Quentin S. Fischer; Nigel W. Daw; Christopher J. Beaver
Sensory neuronopathies (SNs) are a specific subgroup of peripheral nervous system diseases characterized by primary degeneration of dorsal root ganglia and their projections. Multifocal sensory symptoms often associated to ataxia are the classical features of SN. Several different etiologies have been described for SNs, but immune-mediated damage plays a key role in most cases. SN may herald the onset of some systemic autoimmune diseases, which further emphasizes how important the recognition of SN is in clinical practice. We have thus reviewed available clinical, neurophysiological, and therapeutic data on autoimmune disease-related SN, namely, in patients with Sjögren's syndrome, autoimmune hepatitis, and celiac disease.
Martinez, Alberto R. M.; Nunes, Marcelo B.; Nucci, Anamarli; Franca, Marcondes C.
Development and maintenance of unsupervised intelligent activity relies on an active interaction with the environment. Such active exploratory behavior plays an essential role in both the development and adult phases of higher biological systems including humans. Exploration initiates a self-organization process whereby a coherent fusion of different sensory and motor modalities can be achieved (sensory-motor development) and maintained (adult rearrangement). In addition, the development of intelligence depends critically on an active manipulation of the environment. These observations are in sharp contrast with current attempts of artificial intelligence and various neural network models. In this paper, we present a neural network model that combines internal drives and environmental cues to reach behavioral decisions for the exploratory activity. The vision system consists of an ambient and a focal system. The ambient vision system guides eye movements by using nonassociative learning. This sensory based attentional focusing is augmented by a `cognitive' system using models developed for various aspects of frontal lobe function. The combined system has nonassociative learning, reinforcement learning, selective attention, habit formation, and flexible criterion categorization properties.
The distance ?-domination number ??(G) of a strongly connected digraph G is the minimum number ? for which there is a set DV (G) with cardinality ? such that any vertex v \\/ 2 D can be reached within distance ? from some vertex in D. In this paper, we establish a lower bound and an upper bound for ??
|Describes a tentative hypothesis for the control of plant branching (apical dominance). Explores the mechanism by which apical buds inhibit the growth of axillary buds on the same shoot. Presents an up-to-date picture of the problem and gives economic implications of the study. (BR)|
These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided.
To probe how the brain integrates visual motion signals to guide behavior, we analyzed the smooth pursuit eye movements evoked by target motion with a stochastic component. When each dot of a texture executed an independent random walk such that speed or direction varied across the spatial extent of the target, pursuit variance increased as a function of the variance of visual pattern motion. Noise in either target direction or speed increased the variance of both eye speed and direction, implying a common neural noise source for estimating target speed and direction. Spatial averaging was inefficient for targets with >20 dots. Together these data suggest that pursuit performance is limited by the properties of spatial averaging across a noisy population of sensory neurons rather than across the physical stimulus. When targets executed a spatially uniform random walk in time around a central direction of motion, an optimized linear filter that describes the transformation of target motion into eye motion accounted for approximately 50% of the variance in pursuit. Filters had widths of approximately 25 ms, much longer than the impulse response of the eye, and filter shape depended on both the range and correlation time of motion signals, suggesting that filters were products of sensory processing. By quantifying the effects of different levels of stimulus noise on pursuit, we have provided rigorous constraints for understanding sensory population decoding. We have shown how temporal and spatial integration of sensory signals converts noisy population responses into precise motor responses. PMID:19657083
The ability to appropriately interact with the environment is crucial to an organism’s survival. The establishment of functional sensory systems, such as the bristles and eyes in Drosophila, is a critical event during the development of the organism. The transcription factor D Pax2 is involved in the differentiation of the shaft and glial cells in the developing bristle (Kavaler et
Some individuals have reported burning or painful sensations in the eyes or upper respiratory tract when they enter certain indoor environments. Recently, carpets have been suggested as a potential source of organic chemicals that could contribute to this irritation. The sensations are generally termed ‘sensory irritation’ or ‘pungency’, and result from stimulation of trigeminal nerve endings. Indoor air quality is
Irregular facets (If) is a dominant gain-of-function allele of the Drosophila segmentation gene Krüppel (Kr) that interferes with eye development. In a search for genes that interact with Kr activity, we recently performed a systematic genetic screen to identify dominant enhancers and suppressors of the If eye phenotype that are located on the third chromosome. Here we describe locations and
|This month-by-month calendar of suggested sensory activities is intended to be part of the science curriculum in kindergarten and the primary grades. It takes advantage of the child's natural interest in examining the world around him. Lists of natural and man-made objects appropriate to each school month are divided according to the sense to…
The role of caregivers requires that they continuously assess the needs and performance of children and provide the support necessary for them to achieve their potential. A thorough understanding of child development, including the role and impact of sensory development, is critical for caregivers to properly evaluate and assist these children.…
We have developed a genetic approach to visualize axons from olfactory sensory neurons expressing a given odorant receptor, as they project to the olfactory bulb. Neurons expressing a specific receptor project to only two topographically fixed loci among the 1800 glomeruli in the mouse olfactory bulb. Our data provide direct support for a model in which a topographic map of
Peter Mombaerts; Fan Wang; Catherine Dulac; Steve K. Chao; Adriana Nemes; Monica Mendelsohn; James Edmondson; Richard Axel
This program determined the feasibility of using sensory force feedback on a remote controlled continuous miner to improve operator performance, identified parameters to be sensed and relayed to the operator, and developed a prototype control system for field evaluation. However, due to some unforeseen problems involving machine access by participating mine operators the final phase of the program was changed
The purpose of this study was to judge the viability of an operational approach aimed at assessing response styles in reading using the hypothesis of sensory hierarchical organization. A sample of 103 middle-class children from a New York City public school, between the ages of five and seven, took part in a three phase experiment. Phase one…
Sensory systems constantly adapt their responses to match the current environment. These adjustments occur at many levels of the system and increasingly appear to calibrate even for highly abstract perceptual representations of the stimulus. The similar effects of adaptation across very different stimulus domains point to common design principles but also continue to raise questions about the purpose of adaptation.
Designed for instruction of emotionally handicapped children and youth, these seven articles present concepts and activities relative to sensory awareness and outdoor education. The first article presents definitions, concepts, detailed methodology, and over 50 activities designed to create awareness of man's five senses. Utilizing the art of…
|The role of caregivers requires that they continuously assess the needs and performance of children and provide the support necessary for them to achieve their potential. A thorough understanding of child development, including the role and impact of sensory development, is critical for caregivers to properly evaluate and assist these children.…
Electron microscopic studies revealed the presence of true cilia in nerve processes connected with sensory organs of a nematode. These structures are important in evaluating the relation between nematodes and the other aschelminths, from which they were separated partially on the basis of the supposed total absence of cilia.
It has long been recognized that there are striking anatomical similarities between those cilia classically thought of as serving 'sensory' and those serving 'motile' functions. It has also been suggested that sensory cilia evolved from motile cilia, and ...
Objective To determine whether the Sensory Organization Test (SOT) of the computerized dynamic posturography battery or the Clinical Test of Sensory Integration and Balance (CTSIB) is more likely to indicate balance disorders in people with benign paroxysmal positional vertigo. Study design Normal controls were compared to patients with unilateral benign paroxysmal positional vertigo of the posterior semicircular canal (BPPV). Methods Subjects performed tests with eyes open or closed on stable and unstable surfaces, with head still or with head moving at 0.33 Hz in pitch or yaw. Dependent variables were the percent time of the standard duration each subject could perform the task, the number of head motions made, and kinematic variables measured with head- and torso-mounted inertial motion units. Results Because equilibrium scores of normals improved significantly over repeated trials on SOT patients were given only 1 trial per condition. For percent time between-group differences were found on CTSIB with eyes closed, on foam, head moving in yaw showing significantly reduced performance by BPPV subjects compared to controls. Compared to controls patients made significantly fewer head movements on CTSIB, eyes closed, on foam, head still, pitch and yaw. Kinematic data also differed between the groups on tests with eyes closed, unstable surfaces with different head movement combinations, indicating increased instability in BPPV patients. Conclusion For screening, CTSIB with head movements is more likely than SOT to indicate balance deficits, especially when dependent measures include percent time as well as head movement counts and kinematic measures.
Mulavara, Ajitkumar P.; Cohen, Helen S.; Peters, Brian T.; Sangi-Haghpeykar, Haleh; Bloomberg, Jacob J.
Utilizing a multielectrode array to record spontaneous and visually evoked activity of cortical neurons in area 17, we investigate the relationship between long-range correlated spontaneous activity and functional ocular dominance columns during early ferret postnatal development (P24-P29). In regions of visual cortex containing alternating ocular dominance patches, periodic fluctuations in correlated activity are observed in which spontaneous activity is most highly correlated between cortical patches exhibiting the same eye preference. However, these fluctuations are present even within large contralateral eye-dominated bands which lack any periodic alternations in ocular dominance. Thus, the organization of ocular dominance columns cannot fully account for the patterns of correlated activity we observe. Our results suggest that patterns of long-range correlated activity reflect an intrinsic periodicity of cortical connectivity that is constrained by segregated eye-specific LGN afferents. PMID:12354401
To date, several eye input methods have been developed, which, however, are usually designed for specific purposes (e.g. typing) and require dedicated graphical interfaces. In this paper we present Eye-S, a system that allows general input to be provided to the computer through a pure eye-based approach. Thanks to the \\
Recent interest in sensory gating in children with and without neuropsychological disorders has resulted in a number of studies and the results regarding the developmental trajectory of sensory gating are inconsistent. We investigated the maturational course of sensory gating in samples of typically developing children and children with sensory processing deficits (SPD) and compared their performance to adults. Besides gating
Patricia L. Davies; Wen-Pin Chang; William J. Gavin
The sensory aspects of bladder function are not clearly defined, are poorly understood and imperfectly managed. Sensory urgency or bladder hypersensitivity often present with symptoms without an obvious cause (idiopathic sensory urgency). This article reviews the evidence that some of these symptomatic patients are actually suffering from early interstitial cystitis. The implications of such a possibility are discussed and the
The rationale for studying sensory systems as an integral part of neurotoxicological examinations is presented. The role of evoked potentials in assessing brain dysfunction in general and sensory systems in particular is also presented. Four types of sensory evoked potentials (br...
In China temple festivals are replete with noises, sights, smells, tastes, and ambient sensory productions. When worshipers converge on a particular temple festival, they produce and experience honghuo (social heat or red-hot sociality). This native concept of honghuo highlights the importance of the social production of a heightened sensory ambience as well as the sensorial production of sociality. In co-producing
Perception involves motor control of sensory organs. However, the dynamics underlying emergence of perception from motor-sensory interactions are not yet known. Two extreme possibilities are as follows: (1) motor and sensory signals interact within an open-loop scheme in which motor signals determine sensory sampling but are not affected by sensory processing and (2) motor and sensory signals are affected by each other within a closed-loop scheme. We studied the scheme of motor-sensory interactions in humans using a novel object localization task that enabled monitoring the relevant overt motor and sensory variables. We found that motor variables were dynamically controlled within each perceptual trial, such that they gradually converged to steady values. Training on this task resulted in improvement in perceptual acuity, which was achieved solely by changes in motor variables, without any change in the acuity of sensory readout. The within-trial dynamics is captured by a hierarchical closed-loop model in which lower loops actively maintain constant sensory coding, and higher loops maintain constant sensory update flow. These findings demonstrate interchangeability of motor and sensory variables in perception, motor convergence during perception, and a consistent hierarchical closed-loop perceptual model. PMID:23035109
Electroencephalographic measures consistently show that adults with sensory processing deficits (e.g., schizophrenia) have reduced abilities to gate out repetitive information. However, studies contrasting children with and without disabilities are inconclusive due to large within-group variances. Characterizing individual differences may lead to better understanding of sensory gating in children. We examined sensory gating in 22 children ages 5 to 10 years
Wen-Pin Chang; William J. Gavin; Patricia L. Davies
With the recent explosion in the characterization of different sensory systems, a general rule is emerging: only one type of sensory receptor molecule is expressed per receptor neuron. The visual system is no exception and, in most cases, photoreceptors express only one visual pigment per cell. However, the mechanisms underlying the exclusion of sensory receptors are poorly understood. As expression
An observational research study based on sensory integration theory was conducted to examine the observed impact of student selected multi-sensory experiences within a multi-sensory intervention center relative to the sustained focus levels of students with special needs. A stratified random sample of 50 students with severe developmental…
In this activity, learners use a fictitious map of "Tourist Town" and counters to problem solve how to place ice-cream vans on street intersections so that every other intersection is connected to one that has a van on it. Use this activity to introduce learners to computer science themes including nodes, dominating sets, exponential-time algorithms, polynomial-time algorithms, and NP-complete problems. Variations, extensions, background information, and solutions are included in the PDF.
Dominant traits are rare in mitochondrial disorders but include important nosological entities such as alterations of organellar biogenesis and abnormalities in the structural integrity of the mitochondrial genome, determined by mutations in genes involved in its maintenance and propagation. Both haplo-insufficiency and ‘gain-of-function’ mechanisms underlie the pathogenesis of these disorders. Impairment in energy supply, abnormal mitochondrial trafficking, increased toxic damage
Although the mechanisms underlying the spatial pattern formation of sensory maps have been extensively investigated, those triggering sensory map formation during development are largely unknown. Here we show that the birth of pups instructively and selectively regulates the initiation of barrel formation in the somatosensory cortex by reducing serotonin concentration. We found that preterm birth accelerated barrel formation, whereas it did not affect either barreloid formation or barrel structural plasticity. We also found that serotonin was selectively reduced soon after birth and that the reduction of serotonin was triggered by birth. The reduction of serotonin was necessary and sufficient for the effect of birth on barrel formation. Interestingly, the regulatory mechanisms described here were also found to regulate eye-specific segregation in the visual system, suggesting that they are utilized in various brain regions. Our results shed light on roles of birth and serotonin in sensory map formation. PMID:24135230
The influence of the state of "animal hypnosis" in rabbits on the course and preservation of the motor polarizational dominant created by the action of a direct current anode on the region of the sensorimotor cortex was investigated. The mechanogram of both forelimbs was recorded. It was demonstrated that the state of "animal hypnosis" induced against the background of the optimum of the dominant inhibits the motor reaction of the "dominant" limb to sensory test stimuli. This inhibition is maintained for a long time, up to two to four days. The motor polarizational dominant does not extinguish under the influence of "animal hypnosis," but is inhibited; after the extinction of the traces of the "hypnosis," the motor dominant reaction recovers under the influence of sensory test stimuli alone, without the repeated use of the direct current. PMID:8782215
Multicellular sensory hairs were excised from the leaf of Venus's flytrap, and the sensory cells were identified by a destructive dissection tech- nique. The sensory layer includes a radially symmetrical rosette of 20-30 ap- parently identical cells, and the sensory cells are organized in a plane normal to the long axis of the sensory hair. The sensory cells were probed
Due to its vascularisation and system of lymphatic drainage, the eye is privileged territory for development of immunological phenomena. The tears, because of lactoferrin, lysozymes, mucins, different immunoglobulins: IgA (CALT), IgG and IgM, are the first line of defence against physical, chemical, infectious and extra-ocular antigenic attack. ACAID, "Anterior Chamber Associated Immune Deviation", by its type of defence against intra-ocular aggressors, assures some protection of the eye and explains the development of some intra-ocular tumours and tolerance to corneal grafts. PMID:8318143
We examined whether dynamic stimulation that surrounds a rival target influences perceptual alternations during binocular rivalry. We presented a rival target surrounded by dynamic random-dot patterns to both eyes, and measured dominance durations for each eye's rival target. We found that rival target dominance durations were longer when surrounds were dynamic than when they were static or absent. Additionally, prolonged dominance durations were more apparent when the dynamic surround was alternately presented between the two eyes than when it was presented simultaneously to both eyes. These results indicate that dynamic stimulation that surrounds a rival target plays a role in maintaining the current perceptual state, and causes less perceptual alternations during binocular rivalry. Our findings suggest that dynamic signals on the retina may suppress rivalry, and thus provide useful information for stabilizing perceptions in daily life. PMID:24041849
Background Application of virtual environment (VE) technology to motor rehabilitation increases the number of possible rehabilitation tasks and/or exercises. However, enhancing a specific sensory stimulus sometimes causes unpleasant sensations or fatigue, which would in turn decrease motivation for continuous rehabilitation. To select appropriate tasks and/or exercises for individuals, evaluation of physical activity during recovery is necessary, particularly the changes in the relationship between autonomic nervous activity (ANA) and sensory stimuli. Methods We estimated the ANA from the R-R interval time series of electrocardiogram and incoming sensory stimuli that would activate the ANA. For experiments in real exercise, we measured vehicle data and electromyogram signals during cycling exercise. For experiments in virtual exercise, we measured eye movement in relation to image motion vectors while the subject was viewing a mountain-bike video image from a first-person viewpoint. Results For the real cycling exercise, the results were categorized into four groups by evaluating muscle fatigue in relation to the ANA. They suggested that fatigue should be evaluated on the basis of not only muscle activity but also autonomic nervous regulation after exercise. For the virtual exercise, the ANA-related conditions revealed a remarkable time distribution of trigger points that would change eye movement and evoke unpleasant sensations. Conclusion For expanding the options of motor rehabilitation using VE technology, approaches need to be developed for simultaneously monitoring and separately evaluating the activation of autonomic nervous regulation in relation to neuromuscular and sensory systems with different time scales.
Quantitative sensory testing (QST) consists of several non-invasive, standardised tests aimed at examining different aspects of the entire somatosensory nervous system. Important advantages of QST over existing supplementary tests such as electromyography are the ability to test the function of thin and unmyelinated nerve fibres as well as the subjective sensation of a somatosensory stimulus. QST is validated in diagnosing small fibre neuropathy, diabetic neuropathy chemotherapy-induced peripheral neuropathy and neuropathic pain. In scientific research, QST is useful in the study into pathophysiological mechanisms of diseases and syndromes with sensory symptoms and in the evaluation of the effect of analgesic treatment on the function of the somatosensory nervous system. In the future, QST could be a useful diagnostic and prognostic test in more forms of neuropathy and in other clinical conditions such as chronic unexplained pain syndromes (e.g. fibromyalgia and whiplash-associated disorder. PMID:23369816
Verberne, Wouter R; Snijders, Tom J; Liem, K Seng; Baakman, Anne Catrien; Veldhuijzen, Dieuwke S
The discussion of overdentures has been confined to their capacity to use abutment teeth to improve neuromuscular control of mandibular movement. Use of overdentures has been favored often because of their mechanical advantages, but seldom because of the sensory role of the retained abutment teeth. Even though the retained teeth may be periodontally diseased, they still may provide sufficient support for the transmission of masticatory pressures and sufficient periodontal ligament receptors to initiate a jaw opening reflex. Whereas conflicting evidence shows that the periodontal nerve receptors play a role in mandibular positional sensibility (proprioception), pressure perception by the periodontal ligament remains a primary stimulus for the jaw opening reflex. Additional investigations will be essential to a complete understanding of the role of the periodontal ligament receptors. However, recognition of the importance of the periodontal ligament receptors to the overdenture patient as a source of sensory input is vital. PMID:1066472
Previous research showed a cut-off along homologous volatile organic compounds (VOCs) in their ability to produce acute human mucosal irritation. The present study sought to specify the particular cut-off homolog for sensoryeye irritation in an acetate and n-alcohol series. A 1900-ml glass vessel system and a three-alternative forced-choice procedure served to test nonyl, decyl, and dodecyl acetate, and 1-nonanol, 1-decanol, and 1-undecanol. Flowrate to the eye ranged from 2 to 8 L/min and time of exposure from 3 to 24 s. Decyl acetate and 1-undecanol were the shortest homologs that failed to produce eye irritation under all conditions, producing a cut-off effect. Increasing the vapor concentration of decyl acetate and 1-undecanol by 3 and 8 times, respectively, via heating them to 37 deg C made either or both VOCs detectable to only half of the 12 subjects tested, even though the higher vapor concentration was well above a predicted eye irritation threshold. When eye irritation thresholds for homologous acetates and n-alcohols were plotted as a function of the longest unfolded length of the molecule, the values for decyl acetate and 1-undecanol fell within a restricted range of 18 to 19 A. The outcome suggests that the basis for the cut-off is biological, that is, the molecule lacks a key size or structure to trigger transduction, rather than physical, that is, the vapor concentration is too low to precipitate detection.
Cometto-Muniz, J. Enrique [Chemosensory Perception Laboratory, Department of Surgery (Otolaryngology), 9500 Gilman Dr.-Mail Code 0957, University of California, San Diego, La Jolla, CA 92093-0957 (United States)]. E-mail: firstname.lastname@example.org; Cain, William S. [Chemosensory Perception Laboratory, Department of Surgery (Otolaryngology), 9500 Gilman Dr.-Mail Code 0957, University of California, San Diego, La Jolla, CA 92093-0957 (United States); Abraham, Michael H. [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)
Previous findings imply that synaesthetic experience may have consequences for sensory processing of stimuli that do not themselves\\u000a trigger synaesthesia. For example, synaesthetes who experience colour show enhanced perceptual processing of colour compared\\u000a to non-synaesthetes. This study aimed to investigate whether enhanced perceptual processing was a core property of synaesthesia\\u000a by contrasting tactile and colour sensitivity in synaesthetes who experience
In tasks requiring a comparison of the duration of a reference and a test visual cue, the spatial position of test cue is likely to be implicitly coded, providing a form of a congruency effect or introducing a response bias according to the environmental scale or its vectorial reference. The precise mechanism generating these perceptual shifts in subjective duration is not understood, although several studies suggest that spatial attentional factors may play a critical role. Here we use a duration comparison task within and across sensory modalities to examine if temporal performance is also modulated when people are exposed to spatial distractors involving different sensory modalities. Different groups of healthy participants performed duration comparison tasks in separate sessions: a time comparison task of visual stimuli during exposure to spatially presented auditory distractors; and a time comparison task of auditory stimuli during exposure to spatially presented visual distractors. We found the duration of visual stimuli biased depending on the spatial position of auditory distractors. Observers underestimated the duration of stimuli presented in the left spatial field, while there was an overestimation trend in estimating the duration of stimuli presented in the right spatial field. In contrast, timing of auditory stimuli was unaffected by exposure to visual distractors. These results support the existence of multisensory interactions between space and time showing that, in cross-modal paradigms, the presence of auditory distractors can modify visuo-temporal perception but not vice versa. This asymmetry is discussed in terms of sensory perceptual differences between the two systems. PMID:19817148
Vicario, Carmelo Mario; Rappo, Gaetano; Pepi, Anna Maria; Oliveri, Massimiliano
Videobased corneal-reflection-to-pupil-center systems are widely used in eye movement research. In this paper, an artificial\\u000a eye drawn on a computer screen is presented. The artificial eye provides a way to simulate measurements of eye position in\\u000a human subjects. The method allows testing videobased systems on the level of the signal and on the level of the calibration\\u000a algorithm used to
Daniel Cavegn; Johan Van Rensbergen; Géry d’Ydewalle
In the natural world, the brain must handle inherent delays in visual processing. This is a problem particularly during dynamic tasks. A possible solution to visuo-motor delays is prediction of a future state of the environment based on the current state and properties of the environment learned from experience. Prediction is well known to occur in both saccades and pursuit movements and is likely to depend on some kind of internal visual model as the basis for this prediction. However, most evidence comes from controlled laboratory studies using simple paradigms. In this study, we examine eye movements made in the context of demanding natural behavior, while playing squash. We show that prediction is a pervasive component of gaze behavior in this context. We show in addition that these predictive movements are extraordinarily precise and operate continuously in time across multiple trajectories and multiple movements. This suggests that prediction is based on complex dynamic visual models of the way that balls move, accumulated over extensive experience. Since eye, head, arm, and body movements all co-occur, it seems likely that a common internal model of predicted visual state is shared by different effectors to allow flexible coordination patterns. It is generally agreed that internal models are responsible for predicting future sensory state for control of body movements. The present work suggests that model-based prediction is likely to be a pervasive component in natural gaze control as well.
Over the past century, compound eyes in nature have been one of the most studied and intriguing topics in physiological optics due to their unique optical scheme for imaging. Hundreds to ten thousands of integrated optical units called ommatidia are spherically arranged along a curvilinear surface and point in different directions. Each ommatidium collects light within a small angular acceptance
|Art, like beauty, as the adage goes, is in the eye of the beholder. Art also is a living, breathing thing that evolves over time, so what is considered "art" is ever changing--how many of the great artists whose works today sell for fortunes were failures during their lifetime? The 20th century unknowingly gave birth to new variations of art that…
Pregnancy is associated with changes in many organs and systems including the eyes. Sometimes in pregnancy may appear physiological and pathological ocular changes that may be associated with pre-existing problems. In such cases it is very important interdisciplinary collaboration gynecologist, ophthalmologist. PMID:22888682
For years, restoring sight to the blind has been counted as nothing less than miraculous. Today, computer engineering, ophthalmology and biology are uniting in an effort to achieve just that. This article on bio-electronic vision or popularly, “the artificial eye” explains briefly how far the field has come and how far it has yet to go. The following topics are
Although airbags measurably reduce the overall risk of injury to adults (including eye injury), and death from motor vehicle accidents, injuries attributed to airbag deployment have been reported. To identify reported cases of ocular trauma related to airbag deployment, a MEDLINE search from 1991 to 2000 was performed. A total of 263 injuries in 101 patients were identified. Patient demographics,
Joel A Pearlman; K. G. Au Eong; Ferenc Kuhn; Dante J Pieramici
... related macular degeneration (AMD) . And the more a person smokes, the higher the risks. The good news is ... increases the risk of serious vision loss in people with other eye diseases. And when women smoke during pregnancy they are more likely to give ...
We describe and discuss astronomical LOBSTER EYE X-ray telescopes based on Multi Foil Optics including recent results of the development and tests of advanced laboratory samples. An alternative proposal for a space experiment based on this optics - Lobster All Sky Monitor - is also briefly presented and discussed.
Hudec, Rene; Sveda, Libor; Inneman, Adolf; Pina, Ladislav
This paper compares two different methods for combining PCA and ANOVA for sensory profiling data. One of the methods is based on first using PCA on raw data and then relating dominating principal components to the design variables. The other method is based on first estimating ANOVA effects and then using PCA to analyse the different effect matrices. The properties
Modern psychophysics has traveled considerably beyond the threshold measures that dominatedsensory studies in the first half of this century. Current methods capture the range of perceived intensity from threshold to maximum and promise to provide increasingly accurate comparisons of perceived intensities across individuals. The application of new psychophysical tools to genetic variation in taste allowed us to discover supertasters,
Background: Saccades are fast eye movements that conjugately shift the point of fixation between distant features of interest in the visual environment. Several disorders, affecting sites from brainstem to extraocular muscle, may cause horizontal saccades to become disconjugate. Prior techniques for detection of saccadic disconjugacy, especially in internuclear ophthalmoparesis (INO), have compared only one point in abducting vs adducting saccades, such as peak velocity. Methods: We applied a phase-plane technique that compared each eye’s velocity as a function of change in position (normalized displacement) in 22 patients with disease variously affecting the brainstem reticular formation, the abducens nucleus, the medial longitudinal fasciculus, the oculomotor nerve, the abducens nerve, the neuromuscular junction, or the extraocular muscles; 10 age-matched subjects served as controls. Results: We found three different patterns of disconjugacy throughout the course of horizontal saccades: early abnormal velocity disconjugacy during the first 10% of the displacement in patients with INO, oculomotor or abducens nerve palsy, and advanced extraocular muscle disease; late disconjugacy in patients with disease affecting the neuromuscular junction; and variable middle-course disconjugacy in patients with pontine lesions. When normal subjects made disconjugate saccades between two targets aligned on one eye, the initial part of the movement remained conjugate. Conclusions: Along with conventional measures of saccades, such as peak velocity, phase planes provide a useful tool to determine the site, extent, and pathogenesis of disconjugacy. We hypothesize that the pale global extraocular muscle fibers, which drive the high-acceleration component of saccades, receive a neural command that ensures initial ocular conjugacy. GLOSSARY Abd. = abducens; CN = cranial nerve; CPEO = chronic progressive external ophthalmoplegia; EM = eye movement; H = horizontal; INO = internuclear ophthalmoparesis; MG = myasthenia gravis; MLF = medial longitudinal fasciculus; MS = multiple sclerosis; P = patient; PI = prediction interval; PPRF = paramedian pontine reticular formation; RIP = raphe interpositus; V = vertical.
Serra, Alessandro; Liao, Ke; Matta, Manuela; Leigh, R John
... eye that did not develop normal sight during early childhood. It is sometimes called "lazy eye." Amblyopia: What ... time to correct amblyopia is during infancy or early childhood. Amblyopia in children and adults Newborn infants are ...
Background Short monocular deprivation (4 days) induces a shift in the ocular dominance of binocular neurons in the juvenile mouse visual cortex but is ineffective in adults. Recently, it has been shown that an ocular dominance shift can still be elicited in young adults (around 90 days of age) by longer periods of deprivation (7 days). Whether the same is true also for fully mature animals is not yet known. Methodology/Principal Findings We therefore studied the effects of different periods of monocular deprivation (4, 7, 14 days) on ocular dominance in C57Bl/6 mice of different ages (25 days, 90–100 days, 109–158 days, 208–230 days) using optical imaging of intrinsic signals. In addition, we used a virtual optomotor system to monitor visual acuity of the open eye in the same animals during deprivation. We observed that ocular dominance plasticity after 7 days of monocular deprivation was pronounced in young adult mice (90–100 days) but significantly weaker already in the next age group (109–158 days). In animals older than 208 days, ocular dominance plasticity was absent even after 14 days of monocular deprivation. Visual acuity of the open eye increased in all age groups, but this interocular plasticity also declined with age, although to a much lesser degree than the optically detected ocular dominance shift. Conclusions/Significance These data indicate that there is an age-dependence of both ocular dominance plasticity and the enhancement of vision after monocular deprivation in mice: ocular dominance plasticity in binocular visual cortex is most pronounced in young animals, reduced but present in adolescence and absent in fully mature animals older than 110 days of age. Mice are thus not basically different in ocular dominance plasticity from cats and monkeys which is an absolutely essential prerequisite for their use as valid model systems of human visual disorders.
This paper proposes a precise eye detection and eye blink detection algorithm. Eye detection combines and separates scanning results based on an MCT-based AdaBoost detector. The algorithm detects eyes by applying the eye detector to eye candidate regions of a face. To eliminate outliers, we select an eye candidate group by grouping eye candidates. A refinement process using the average
Here we report exceptionally preserved non-biomineralized compound eyes of a non-trilobite arthropod Cindarella eucalla from the lower Cambrian Chengjiang Lagerstätte, China. The specimen represents the oldest microanatomical evidence confirming the occurrence of highly developed vision in the early Cambrian, over 2,000 ommatidia in each eye. Moreover, a quantitative analysis of the distribution of eyes related to life habit, feeding types, and phyla respectively, from the Chengjiang biota indicates that specimens with eyes mostly belong to the arthropods, and they usually were actively mobile epifaunal and nektonic forms as hunters or scavengers. Arthropods took the lead in evolution of 'good vision' and domination in Cambrian communities, which supports the hypothesis that the origin and evolution of 'good vision' was a key trait that promoted preferential diversification and formed the foundation of modern benthic ecosystems in the early Cambrian ocean. PMID:24067397
This chapter starts with a description of the optics of camera-type eyes, in which an image is projected upon a retina with\\u000a cornea and lens as refracting elements. Ray tracing is explained with the human eye as an example of a terrestrial vertebrate’s\\u000a eye. Then the comparison is made to camera eyes of aquatic and amphibious animals, with an explanation
Dystonia is a term used to describe a specific set of abnormal movements that can occur as a symptom of a variety of neurologic disorders, but also as a disease entity in its own right. This review focuses on the primary dystonias and delineates the genetic contribution to these disorders. Included is a description of the well recognized forms of primary dystonias which manifest autosomal dominant inheritance, especially the "classic" type of early onset, generalized torsion dystonia, but also other clinically distinct forms such as myoclonic dystonia, paroxysmal dystonia, and DOPA-responsive dystonia. Also, a summary of the molecular genetic studies pertinent to these disorders and a discussion of the implications of recent genetic research for delineating the wide spectrum of this phenotypically and genetically heterogeneous group of diseases are forthcoming. PMID:1341964
Explains a laboratory experiment dealing with the optical features of the human eye. Shows how to measure the magnification of the retina and the refractive anomaly of the eye could be used to measure the refractive power of the observer's eye. (GA)
|Explains a laboratory experiment dealing with the optical features of the human eye. Shows how to measure the magnification of the retina and the refractive anomaly of the eye could be used to measure the refractive power of the observer's eye. (GA)|
In Thoreau's Walden, a lake is described as the landscape's most expressive feature and the earth's eye. Collectively, scientists are charged by society to assess, monitor, and remedy maladies of earth's eye in the same way optometrists maintain the health of the human eye. This ...
The shared roles of Pax6 and Six homologues in the eye development of various bilaterians suggest that Urbilateria, the common ancestors of all Bilateria, already possessed some simple form of eyes. Here, we re-address the homology of bilaterian cerebral eyes at the level of eye anatomy, of eye-constituting cell types and of phototransductory molecules. The most widespread eye type found in Bilateria are the larval pigment-cup eyes located to the left and right of the apical organ in primary, ciliary larvae of Protostomia and Deuterostomia. They can be as simple as comprising a single pigment cell and a single photoreceptor cell in inverse orientation. Another more elaborate type of cerebral pigment-cup eyes with an everse arrangement of photoreceptor cells is found in adult Protostomia. Both inverse larval and everse adult eyes employ rhabdomeric photoreceptor cells and thus differ from the chordate cerebral eyes with ciliary photoreceptors. This is highly significant because on the molecular level we find that for phototransduction rhabdomeric versus ciliary photoreceptor cells employ divergent rhodopsins and non-orthologous G-proteins, rhodopsin kinases and arrestins. Our comparison supports homology of cerebral eyes in Protostomia; it challenges, however, homology of chordate and non-chordate cerebral eyes that employ photoreceptor cells with non-orthologous phototransductory cascades.
The eyes are important facial landmarks, both for image normalization due to their relatively constant interocular distance, and for post processing due to their anchoring model-based schemes. In this paper a hierarchical classifier for precise eye location algorithm is introduced. The new algorithm involves three main steps. First, a classifier based on AdaBoost algorithm is introduced to locate eye pair
Gao-Feng Xu; Lei Huang; Chang-Ping Liu; Shi-Qi Ding
Students examine the structure and function of the human eye, learning some amazing features about our eyes, which provide us with sight and an understanding of our surroundings. Students also learn about some common eye problems and the biomedical devices and medical procedures that resolve or help to lessen the effects of these vision deficiencies, including vision correction surgery.
We propose experimental adaptive eye model based on flexible 18-electrode bimorph mirror reproducing human eye aberrations up to 4th radial order of Zernike polynomials at frequency of 10Hz. The accuracy of aberrations reproduction in most cases is better than ?/10 RMS. The model is introduced to aberrometer for human eye aberrations compensation to improve visual acuity test.
The incidence of eye injuries in the coal mining industry in one British Coal Area in 1 year is presented and discussed. The discussion reviews the literature on eye injuries generally. The problems of ensuring adequate eye protection in mining operations are described: plans for a future survey to pinpoint critical areas are outlined. PMID:2599638
... having eye cancer What happens after treatment for eye cancer? For many people with eye cancer, treatment ... manage them. Follow-up after treatment of uveal (eye) melanoma Following treatment, your doctor will most likely ...
Wide availability of highly palatable foods is often blamed for the rising incidence of obesity. As palatability is largely determined by the sensory properties of food, this study investigated how sensitivity to these properties affects how much we eat. Forty females were classified as either high or low in sensory sensitivity based on their scores on a self-report measure of sensory processing (the Adult Sensory Profile), and their intake of chocolate during the experiment was measured. Food intake was significantly higher for high-sensitivity compared to low-sensitivity individuals. Furthermore, individual scores of sensory sensitivity were positively correlated with self-reported emotional eating. These data could indicate that individuals who are more sensitive to the sensory properties of food have a heightened perception of palatability, which, in turn, leads to a greater food intake.
In the course of evolution, the strong and unremitting selective pressure on sensory performance has driven the acuity of sensory organs to its physical limits. As a consequence, the study of primary sensory processes illustrates impressively how far a physiological function can be improved, if the survival of a species depends on it. Sensory cells that detect single-photons, single molecules, mechanical motions on a nanometer scale, or incredibly small fluctuations of electromagnetic fields have fascinated physiologists for a long time. It is a great challenge to understand the primary sensory processes on a molecular level. This chapter points out some important recent developments in the search for primary processes in sensory cells that mediate touch perception, hearing, vision, taste, olfaction, as well as the analysis of light polarization and the orientation in the Earth's magnetic field. The data are screened for common transduction strategies and common transduction molecules, an aspect that may be helpful for researchers in the field. PMID:22399394
Wide availability of highly palatable foods is often blamed for the rising incidence of obesity. As palatability is largely determined by the sensory properties of food, this study investigated how sensitivity to these properties affects how much we eat. Forty females were classified as either high or low in sensory sensitivity based on their scores on a self-report measure of sensory processing (the Adult Sensory Profile), and their intake of chocolate during the experiment was measured. Food intake was significantly higher for high-sensitivity compared to low-sensitivity individuals. Furthermore, individual scores of sensory sensitivity were positively correlated with self-reported emotional eating. These data could indicate that individuals who are more sensitive to the sensory properties of food have a heightened perception of palatability, which, in turn, leads to a greater food intake. PMID:22916284
The Department of Pathology at the University of Pittsburgh Medical Center has compiled a wide range of pathology case studies to aid students and instructors in the medical/health science field. This particular case focuses on a 30-year-old man with a history of focal numbness, bladder and bowel dysfunction, and progressive sensory abnormalities. The patientÃ¢ÂÂs history, images from an MRI, microscopic images of a specimen collected during his laminectomy, and final diagnosis are provided in this case for your review. Students will find this resource especially helpful, as it provides experience with patient history, lab results, and diagnostics.
Smith, Sharyn; Lownie, Steven P.; Duggal, Neil; Hammond, Robert R.
We report sensory changes after tongue reduction by the Harada-Enomoto method for macroglossia in a 20-year-old woman with Beckwith-Wiedemann syndrome. Sensory tests were performed before surgery and 1 week and 2 months after surgery. We assessed the static tactile threshold, vibration sense, static 2-point discrimination, pain threshold, and taste. No sensory loss of any category tested was observed after tongue reduction. PMID:22901656
Matsumoto, Kanako; Morita, Kei-Ichi; Jinno, Shigeharu; Omura, Ken
Aims: To report a case series of enophthalmic patients with lagophthalmos. Methods: A retrospective review of the electronic medical records at a tertiary health care centre of all patients with the diagnoses of “enophthalmos” and “lagophthalmos”. Patients who had a history of diseases (such as Graves’ orbitopathy), trauma or surgery of the orbit and eyelid were excluded. Enophthalmos was defined as exophthalmometric reading of 14 mm or less in both eyes. Results: Seven patients (14 eyes) with bilateral enophthalmos were found to have concomitant lagophthalmos. All patients had deep superior sulci bilaterally. The upper eyelids were seen to be severely retro-placed behind the superior orbital rim. The extraocular motilities were full with no focal neurological deficit. The orbicularis oculi function was normal with no facial paralysis. The orbits were soft on retropulsion and no facial asymmetry was noted. The mean exophthalmolmetry reading measured 12.6 (SD 1.1) mm. The lagophthalmos varied from 1–5 mm. One patient (one eye) with 3 mm lagophthalmos developed a corneal ulcer and was treated with topical antibiotics and gold weight placement in the upper eyelid. Conclusion: Enophthalmic patients with deep superior sulci and retro-placed upper eyelids may present with lagophthalmos and exposure keratopathy.
Yip, C-C; Gonzalez-Candial, M; Jain, A; Goldberg, R A; McCann, J D
Six families are described with hereditary motor and sensory neuropathy (HMSN) of probable autosomal recessive inheritance. Four of these were classified as HMSN type I and two as type II. The consanguinity rate in this series was high, suggesting that these recessive genes are rare. In comparison with the dominantly inherited forms of these disorders, the mean age of onset was significantly earlier for the type II cases but did not differ for the type I patients. Motor nerve conduction velocity was significantly less for the type I cases but did not differ for the type II form. The recessive type I cases tended to show a greater incidence of weakness, ataxia, tendon areflexia and scoliosis than in the dominant form. The importance of differentiating such cases from Friedreich's ataxia is emphasised. Images
Background Scoliosis is the most common type of spinal deformity. In North American children, adolescent idiopathic scoliosis (AIS) makes up about 90% of all cases of scoliosis. While its prevalence is about 2% to 3% in children aged between 10 to 16 years, girls are more at risk than boys for severe progression with a ratio of 3.6 to 1. The aim of the present study was to test the hypothesis that idiopathic scoliosis interferes with the mechanisms responsible for sensory-reweighting during balance control. Methods Eight scoliosis patients (seven female and one male; mean age: 16.4 years) and nine healthy adolescents (average age 16.5 years) participated in the experiment. Visual and ankle proprioceptive information was perturbed (eyes closed and/or tendon vibration) suddenly and then returned to normal (eyes open and/or no tendon vibration). An AMTI force platform was used to compute centre of pressure root mean squared velocity and sway density curve. Results For the control condition (eyes open and no tendon vibration), adolescent idiopathic scoliosis patients had a greater centre of pressure root mean squared velocity (variability) than control participants. Reintegration of ankle proprioception, when vision was either available or removed, led to an increased centre of pressure velocity variability for the adolescent idiopathic scoliosis patients whereas the control participants reduced their centre of pressure velocity variability. Moreover, in the absence of vision, adolescent idiopathic scoliosis exhibited an increased centre of pressure velocity variability when ankle proprioception was returned to normal (i.e. tendon vibration stopped). The analysis of the sway density plot suggests that adolescent idiopathic scoliosis patients, during sensory reintegration, do not scale appropriately their balance control commands. Conclusion Altogether, the present results demonstrate that idiopathic scoliosis adolescents have difficulty in reweighting sensory inputs following a brief period of sensory deprivation.
Polycystins belong to the superfamily of transient receptor potential (TRP) channels and comprise five PKD1-like and three PKD2-like (TRPP) subunits. In this chapter, we review the general properties of polycystins and discuss their specific role in both mechanotransduction and chemoreception. The heteromer PKD1/PKD2 expressed at the membrane of the primary cilium of kidney epithelial cells is proposed to form a mechano-sensitive calcium channel that is opened by physiological fluid flow. Dysfunction or loss of PKD1 or PKD2 polycystin genes may be responsible for the inability of epithelial cells to sense mechanical cues, thus provoking autosomal dominant polycystic kidney disease (ADPKD), one of the most prevalent genetic kidney disorders. pkd1 and pkd2 knock-out mice recapitulate the human disease. Similarly, PKD2 may function as a mechanosensory calcium channel in the immotile monocilia of the developing node transducing leftward flow into an increase in calcium and specifying the left-right axis. pkd2, unlike pkd1 knock-out embryos are characterized by right lung isomerism (situs inversus). Mechanical stimuli also induce cleavage and nuclear translocation of the PKD1 C-terminal tail, which enters the nucleus and initiates signaling processes involving the AP-1, STAT6 and P100 pathways. This intraproteolytic mechanism is implicated in the transduction of a change in renal fluid flow to a transcriptional long-term response. The heteromer PKD1L3/PKD2L1 is the basis for acid sensing in specialised sensory cells including the taste bud cells responsible for sour taste. Moreover, PKD1L3/PKD2L1 may be implicated in the chemosensitivity of neurons surrounding the spinal cord canal, sensing protons in the cerebrospinal fluid. These recent results demonstrate that polycystins fulfill a major sensory role in a variety of cells including kidney epithelial cells, taste buds cells and spinal cord neurons. Such mechanisms are involved in short- and long-term physiological regulation. Alteration of these pathways culminates in severe human pathologies, including ADPKD.
Let G = (V,E) be a graph. A set S V is a restrained dominating set if every vertex in V S is adjacent to a vertex in S and to a vertex in V S. The restrained domination number of G, denoted by r(G), is the minimum cardinality of a restrained dominating set of G. A unicyclic graph is
Johannes H. Hattingh; Ernst J. Joubert; Marc Loizeaux; Andrew R. Plummer; Lucas van der Merwe
Most reports of sensory symptoms in autism are second hand or observational, and there is little evidence of a neurological\\u000a basis. Sixty individuals with high-functioning autism and 61 matched typical participants were administered a sensory questionnaire\\u000a and neuropsychological tests of elementary and higher cortical sensory perception. Thirty-two percent of autism participants\\u000a endorsed more sensory sensitivity items than any control participants.
Signals related to eye position are essential for visual perception and eye movements, and are powerful modulators of sensory responses in many regions of the visual and oculomotor systems. We show that visual and pre-saccadic responses of frontal eye field (FEF) neurons are modulated by initial eye position in a way suggestive of a multiplicative mechanism (gain field). Furthermore the slope of the eye position sensitivity tends to be negatively correlated with preferred retinal position across the population. A model with Gaussian visual receptive fields and linear-rectified eye position gain fields accounts for a large portion of the variance in the recorded data. Using physiologically derived parameters, this model is able to subtract the gaze shift from the vector representing the retinal location of the target. This computation might be used to maintain a memory of target location in space during ongoing eye movements. This updated spatial memory can be read directly from the locus of the peak of activity across the retinotopic map of FEF and it is the result of a vector subtraction between retinal target location when flashed and subsequent eye displacement in the dark.
We examine the anatomical basis for the representation of stimulus parameters within a neural map and examine the extraction of these parameters by sensory interneurons (INs) in the cricket cercal sensory system. The extraction of air current direction by these sensory interneurons can be understood largely in terms of the anatomy of the system. There are two critical anatomical constraints.
The major question posed in the current study was how temperament and sensory processing variables predict maternal behavior in interactions with toddlers identified as having sensory processing disorders. Partici- pants were 49 mothers and infants with sensory processing disorders. They were videotaped in a free-play interaction. Observations were coded using general interaction criteria and criteria of teaching behavior (mediation). A
Pnina S. Klein; Renat Laish-Mishali; Nurit Jaegermann
In the compound lateral eye of Limulus each ommatidium functions as a single receptor unit in the discharge of impulses in the optic nerve. Impulses originate in the eccentric cell of each ommatidium and are conducted in its axon, which runs without interruption through an extensive plexus of nerve fibers to become a fiber of the optic nerve. The plexus makes interconnections among the ommatidia, but its exact organization is not understood. The ability of an ommatidium to discharge impulses in the axon of its eccentric cell is reduced by illumination of other ommatidia in its neighborhood: the threshold to light is raised, the number of impulses discharged in response to a suprathreshold flash of light is diminished, and the frequency with which impulses are discharged during steady illumination is decreased. Also, the activity that can be elicited under certain conditions when an ommatidium is in darkness can be inhibited similarly. There is no evidence for the spread of excitatory influences in the eye of Limulus. The inhibitory influence exerted upon an ommatidium that is discharging impulses at a steady rate begins, shortly after the onset of the illumination on neighboring ommatidia, with a sudden deep minimum in the frequency of discharge. After partial recovery, the frequency is maintained at a depressed level until the illumination on the neighboring receptors is turned off, following which there is prompt, though not instantaneous recovery to the original frequency. The inhibition is exerted directly upon the sensitive structure within the ommatidium: it has been observed when the impulses were recorded by a microelectrode thrust into an ommatidium, as well as when they were recorded more proximally in single fibers dissected from the optic nerve. Receptor units of the eye often inhibit one another mutually. This has been observed by recording the activity of two optic nerve fibers simultaneously. The mediation of the inhibitory influence appears to depend upon the integrity of nervous interconnections in the plexus: cutting the lateral connections to an ommatidium abolishes the inhibition exerted upon it. The nature of the influence that is mediated by the plexus and the mechanism whereby it exerts its inhibitory action on the receptor units are not known. The depression of the frequency of the discharge of nerve impulses from an ommatidium increases approximately linearly with the logarithm of the intensity of illumination on receptors in its vicinity. Inhibition of the discharge from an ommatidium is greater the larger the area of the eye illuminated in its vicinity. However, equal increments of area become less effective as the total area is increased. The response of an ommatidium is most effectively inhibited by the illumination of ommatidia that are close to it; the effectiveness diminishes with increasing distance, but may extend for several millimeters. Illumination of a fixed region of the eye at constant intensity produces a depression of the frequency of discharge of impulses from a nearby ommatidium that is approximately constant, irrespective of the level of excitation of the ommatidium. The inhibitory interaction in the eye of Limulus is an integrative process that is important in determining the patterns of nervous activity in the visual system. It is analogous to the inhibitory component of the interaction that takes place in the vertebrate retina. Inhibitory interaction results in the exaggeration of differences in sensory activity from different regions of the eye illuminated at different intensities, thus enhancing visual contrast.
Active motor processes are present in many sensory systems to enhance perception. In the human visual system, miniature eye movements are produced involuntarily and unconsciously when we fixate a stationary target. These fixational eye movements represent self-generated noise which serves important perceptual functions. Here we investigate fixational eye movements under the influence of external noise. In a two-choice discrimination task, the target stimulus performed a random walk with varying noise intensity. We observe noise-enhanced discrimination of the target stimulus characterized by a U-shaped curve of manual response times as a function of the diffusion constant of the stimulus. Based on the experiments, we develop a stochastic information-accumulator model for stimulus discrimination in a noisy environment. Our results provide a new explanation for the constructive role of fixational eye movements in visual perception.
Active motor processes are present in many sensory systems to enhance perception. In the human visual system, miniature eye movements are produced involuntarily and unconsciously when we fixate a stationary target. These fixational eye movements represent self-generated noise which serves important perceptual functions. Here we investigate fixational eye movements under the influence of external noise. In a two-choice discrimination task, the target stimulus performed a random walk with varying noise intensity. We observe noise-enhanced discrimination of the target stimulus characterized by a U-shaped curve of manual response times as a function of the diffusion constant of the stimulus. Based on the experiments, we develop a stochastic information-accumulator model for stimulus discrimination in a noisy environment. Our results provide a new explanation for the constructive role of fixational eye movements in visual perception. PMID:19335016
Eye Closure, Eye Movements (ECEM) is a hypnotically-based approach to treatment that incorporates eye movements adapted from the Eye Movement Desensitization and Reprocessing (EMDR) protocol in conjunction with hypnosis for the treatment of depersonalization disorder. Depersonalization Disorder has been differentiated from post-traumatic stress disorders and has recently been conceptualized as a subtype of panic disorder (Baker et al., 2003; David, Phillips, Medford, & Sierra, 2004; Segui et. al., 2000). During ECEM, while remaining in a hypnotic state, clients self-generated six to seven trials of eye movements to reduce anticipatory anxiety associated with depersonalization disorder. Eye movements were also used to process triggers that elicited breath holding, often followed by episodes of depersonalization. Hypnotic suggestions were used to reverse core symptoms of depersonalization, subjectively described as "feeling unreal" (Simeon et al., 1997). PMID:19862896
Monocular visual deprivation (MD) produces profound changes in the ocular dominance (OD) of neurons in the visual cortex. MD shifts visually evoked responses away from the deprived eye and toward domination by the open-eye. Over 30 years ago, two different theories were proposed to account for these changes: either through effects on excitatory visual drive, thereby shifting the balance of excitation in favor of the open-eye, or through effects on intracortical inhibition, thereby suppressing responses from the deprived eye. In the intervening years, a scientific consensus emerged that the major functional effects of MD result from plasticity at excitatory connections in the visual cortex. A recent study by Yazaki-Sugiyama et al. (2009) in mouse visual cortex appears to re-open the debate. Here we take a critical look at these intriguing new data in the context of other recent findings in rodent visual cortex.
This paper presents an efficient approach to achieve fast and accurate eye states detection in still gray level images with unconstrained background. The structure of eye region is used as a robust cue to find eye pair candidates. Eyes are located by eye verification using SVMs. The eye contour information is used to detect whether eyes are open or closed
Abstract The emergence of power retailers, such as Wal-mart, Best Buy, and Home Depot, has signif- icantly changed the competitive landscape in the retailing industry over the past two decades. These power retailers frequently dominate other small retailers by charging lower prices (market dominance). Some also pursue the strategy of dominating the distribution channel by partic- ipating in setting the
Prenatal exposure to alcohol can result in a spectrum of adverse developmental outcomes, collectively termed fetal alcohol spectrum disorders (FASDs). This study evaluated deficits in sensory, motor and cognitive processing in children with FASD that can be identified using eye movement testing. Our study group was composed of 89 children aged 8-15 years with a diagnosis within the FASD spectrum
C. R. Green; A. M. Mihic; D. C. Brien; I. T. Armstrong; S. M. Nikkel; B. C. Stade; C. Rasmussen; D. P. Munoz; J. N. Reynolds
Little scientific investigation has been conducted to examine the sensory and physical alterations experienced by women after mastectomy. No researchers have systematically examined the changes over time. In this study women were interviewed at five time periods during the first year after mastectomy (at 1, 4, 7, 10, and 12 months). Sensory alterations such as “numbness”; and “tightness”; were categorized
Sensory engineering is defined to be the science and technology of synthetic environments. This emerging discipline incorporates such technologies as virtual environments and virtual reality, data visualization, human sensory system modeling, human-machine interface, and perception, cognition and performance characterization. An educational curriculum requires basic science in the fields of computer science, electrical engineering, psychology, physiology, the biomedical sciences, and mathematics.
The increasing requirement for sensory laboratories to show that the results they provide are repeatable by other laboratories has meant that ways of measuring this are required. One way to achieve this is to undertake ring trials on the same product, using different panels. If the sensory method is used correctly, and the panels are trained, the same conclusions should
Sensory quality is the ultimate measure of product quality and success. Sensory analysis comprises a vari- ety of powerful and sensitive tools to measure human responses to foods and other products. Selection of the appropriate test, test conditions, and data analysis re- sult in reproducible, powerful, and relevant results. Ap- propriate application of these tests enables specific product and consumer
Electric fish of the Amazon Basin and Nile River are equipped with electric-generator-receiver organs for both sensory perception and communication. These fish are superbly adapted for life in turbulent, muddy streams and, therefore, provide and excellent illustration of the input of environmental information into central nervous systems via specialized sensory windows.
Patricia J. DeCoursey (University of South Carolina;)
Intracellular recordings were made from neurons of the trigeminal sensory ganglia of young adult sea lampreys. Receptive fields were mapped, and four classes of sensory cells were identified. Touch cells gave rapidly adapting responses to indentation of the skin. Pressure cells gave slowly adapting responses to indentation of the skin. Pit organ cells gave slowly adapting responses to mechanical stimulation
This study investigates the influence of allergic inflammation in airway sensory innervation. We conclude that allergic inflammation in the guinea pig leads to both an increase in excitability, as manifested by an increase in the mechanical sensitivity of the airway nerve endings, and an induction of substance P production in airway sensory neurons. The data are consistent with the hypothesis
Bradley J. Undem; Dawn D. Hunter; Mark Liu; Angela Oakragly; Axel Fischer
Ubiquitous computing is making it possible to increase the sensory feedback from everyday spaces to attract attention to often-neglected tasks, make them safer and easier and potentially motivate new behavior. Hyper- Reality describes distributed computing interfaces that weave existing envi- ronments with immersive sound and images to expand sensory feedback from everyday activities. This paper discusses the design and background
ŠEDIVÁ A., PANOVSK Á Z., POKORN Ý J. (2006): Sensory profiles of sweeteners in aqueous solutions. Czech J. Food Sci., 24: 283-287. Sensory profiles of saccharin, acesulfame K, aspartame, and neotame were compared with that of sucrose in three different types of water (tap water, commerical Crystalis water, and distilled water) under the conditions of the respec- tive ISO standards.
Lack of a knowledge-base for predicting how genetic, pre-harvest, and post-harvest factors affect the sensory characteristics of rice results in producers and processors not having control over the sensory quality of their products. In this study, differences in the texture and flavor of seventeen ...
A peripheral sensory neuropathy was diagnosed in two Border collie puppies. Neurological, electrophysiological and histopathological examinations suggested a purely sensory neuropathy with mainly distal involvement. Urinary incontinence was observed in one of the puppies and histological examination of the vagus nerve revealed degenerative changes. An inherited disorder was suspected. PMID:15971901
Vermeersch, K; Van Ham, L; Braund, K G; Bhatti, S; Tshamala, M; Chiers, K; Schrauwen, E
BACKGROUND: Avoidance of noxious stimuli is essential for the survival of an animal in its natural habitat. Some avoidance responses require polymodal sensory neurons, which sense a range of diverse stimuli, whereas other stimuli require a unimodal sensory neuron, which senses a single stimulus. Polymodality might have evolved to help animals quickly detect and respond to diverse noxious stimuli. Nematodes
An evolutionary design synthesis methodology was introduced with special concern for the design and optimization of distributed embodied systems. Its efficacy was validated in a case study on the design of collective sensory configurations for intelligent vehicles. Candidate sensory configurations were tested in sample traffic scenarios simulated in an embodied and sensor-based simulator, and in more abstracted and computationally efficient
Yizhen Zhang; Alcherio Martinoli; Erik K. Antonsson; Ross D. Olney
The filarial parasite Loa loa is transmitted by Chrysops fly bites. Loiasis is endemic in rainforest areas of West and Central Africa, and sporadic cases have also been diagnosed in travellers and migrants. Whilst many infected persons are asymptomatic, microfilariae may be detected in the blood or adult worms may be seen under the skin or the sclera of the eye. Mass treatment programmes for onchocerciasis have raised concern about the risk of severe adverse effects when ivermectin is distributed in areas co-endemic for onchocerciasis and loiasis. PMID:18466939
EyeGaze is a British company that has developed video technology that can be used by profoundly and partially deaf people. One example of their services and technology is a remote video interpreting centre. The project is managed by a team of Deaf and hearing individuals with diverse skills and experiences, "which affords us a holistic view of issues surrounding communication, information delivery and the Deaf community." The website provides an overview of their research and services, as well as some information on issues in the deaf community.
Gallaudet University of Washington DC is presenting a travelling exhibition entitled History Through Deaf Eyes. At this Website, readers can learn about the plan, curator, and travel specifics of the exhibition that seeks to place the social history of deaf Americans within the context of better-known aspects of American history and to trace the development of a Deaf identity and language. Contents of the Website are Introduction and Orientation, Formation of Community, An Oral Approach to Education, The War and Post-War Years, Civil Rights Recognition and Access, Information Age, and Choices. Interesting historical photographs accompany the engaging text.
Definition of the disease Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC) and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain. Epidemiology The prevalence of the disease varies from 1/10000 in Denmark due to a founder effect, to 1/30000 in the rest of the world. Clinical description DOA patients usually suffer of moderate visual loss, associated with central or paracentral visual field deficits and color vision defects. The severity of the disease is highly variable, the visual acuity ranging from normal to legal blindness. The ophthalmic examination discloses on fundoscopy isolated optic disc pallor or atrophy, related to the RGC death. About 20% of DOA patients harbour extraocular multi-systemic features, including neurosensory hearing loss, or less commonly chronic progressive external ophthalmoplegia, myopathy, peripheral neuropathy, multiple sclerosis-like illness, spastic paraplegia or cataracts. Aetiology Two genes (OPA1, OPA3) encoding inner mitochondrial membrane proteins and three loci (OPA4, OPA5, OPA8) are currently known for DOA. Additional loci and genes (OPA2, OPA6 and OPA7) are responsible for X-linked or recessive optic atrophy. All OPA genes yet identified encode mitochondrial proteins embedded in the inner membrane and ubiquitously expressed, as are the proteins mutated in the Leber Hereditary Optic Neuropathy. OPA1 mutations affect mitochondrial fusion, energy metabolism, control of apoptosis, calcium clearance and maintenance of mitochondrial genome integrity. OPA3 mutations only affect the energy metabolism and the control of apoptosis. Diagnosis Patients are usually diagnosed during their early childhood, because of bilateral, mild, otherwise unexplained visual loss related to optic discs pallor or atrophy, and typically occurring in the context of a family history of DOA. Optical Coherence Tomography further discloses non-specific thinning of retinal nerve fiber layer, but a normal morphology of the photoreceptors layers. Abnormal visual evoked potentials and pattern ERG may also reflect the dysfunction of the RGCs and their axons. Molecular diagnosis is provided by the identification of a mutation in the OPA1 gene (75% of DOA patients) or in the OPA3 gene (1% of patients). Prognosis Visual loss in DOA may progress during puberty until adulthood, with very slow subsequent chronic progression in most of the cases. On the opposite, in DOA patients with associated extra-ocular features, the visual loss may be more severe over time. Management To date, there is no preventative or curative treatment in DOA; severely visually impaired patients may benefit from low vision aids. Genetic counseling is commonly offered and patients are advised to avoid alcohol and tobacco consumption, as well as the use of medications that may interfere with mitochondrial metabolism. Gene and pharmacological therapies for DOA are currently under investigation.
One of the challenges facing prosthetic designers and engineers is to restore the missing sensory function inherit to hand amputation. Several different techniques can be employed to provide amputees with sensory feedback: sensory substitution methods where the recorded stimulus is not only transferred to the amputee, but also translated to a different modality (modality-matched feedback), which transfers the stimulus without translation and direct neural stimulation, which interacts directly with peripheral afferent nerves. This paper presents an overview of the principal works and devices employed to provide upper limb amputees with sensory feedback. The focus is on sensory substitution and modality matched feedback; the principal features, advantages and disadvantages of the different methods are presented. PMID:23278223
Ocular dominance (OD) columns, alternating regions of left and right eye input in the visual cortex of higher mammals, have long been thought to develop from an initially intermingled state by an activity-dependent process. While indirect evidence points to potential alternative mechanisms based on molecular cues, direct proof for a molecular difference between left- and right eye columns is missing. Here, we show that heat shock protein 90 alpha (Hsp90?) is expressed in a clustered fashion in the developing cat visual cortex. Clusters of Hsp90?-positive cells are in register with OD columns of the ipsilateral eye as early as postnatal day 16, when OD columns have just appeared. Importantly, a periodic, clustered expression of Hsp90? is already present weeks before OD columns have started to form, suggesting that molecular differences between future left and right eye OD columns may contribute to the segregated termination of eye specific afferents in the developing visual cortex. PMID:22892426
Sharks and rays possess electrosensors that provide environmental data assisting such tasks as prey detection and mate location. These organs are also incredibly sensitive to minute changes in temperature, and their reaction to temperature is unlike any other thermoreceptor known in nature. We have collected samples of the extracellular gel that fills the electrosensitive organs, and, while characterizing its material properties, we have found an average thermopower of roughly 300 microvolts/Kelvin. We will discuss the implications of these data in terms of a novel, noncellular mode of sensory transduction, in which a thermal fluctuation is translated into an electrical stimulus by the gel. We will also contrast the gel to more established thermoelectric materials.
This paper provides a summary of routine evoked potential tests used with rats, with elaboration on the cochlear microphonic portion of the auditory brainstem response, the effects of chemicals on high frequency (above 40 Hz) components of the somatosensory evoked potential, on cerebellar recording of sensory evoked potentials, and on central conduction time. An alternative to peak-valley amplitude and latency measurements is discussed, wherein a computer analyzes evoked potentials for differences from control in waveform shape, latency, and power. Since multiple use of statistics is common, resulting in an inflated false positive rate, an alpha criterion of less than 0.05 is recommended. Instead of dividing alpha by the number of statistical tests (Bonferroni), a less severe correction of dividing alpha by the square root of the number of tests is proposed. PMID:3073306
Sensory organs of the inner ear of laboratory animals have been examined using scanning electron microscopy. Cochlea sensory cells possess sensory cilia (stereocilia), and bending of the cilia towards Hensen's cell causes excitation of the cell. The tall ...
... that primarily affects the sensory nerve cells (sensory neurons), which transmit information about sensations such as pain, ... the sensations of pain, temperature, and touch (sensory neurons). The mutations involved in HSAN2A result in an ...
What if eye trackers could be downloaded and used immediately with standard cameras connected to a computer, without the need for an expert to setup the system? This has already the case for head trackers, so why not for eye trackers?Using components off-the-shelf (COTS) for camera-based eye tracking tasks has many advantages, but it certainly introduces several new problems as
Dan Witzner Hansen; David J. C. MacKay; John Paulin Hansen; Mads Nielsen
this prediction by comparing the SO-evoked blinks of individuals with dry eye with those of age-matched con- trols. Given the frequent occurrence of dry eye at the onset of benign essential blepharospasm (BEB),7 blink modifications associated with dry eye may play a role in the origin of BEB. We present a hypothesis that links the adaptive processes initiated by dry
Craig Evinger; Jian-Bin Bao; Alice S. Powers; Iris S. Kassem; Edward J. Schicatano; Victor M. Henriquez; Kavita R. Peshori
Impairments of sensory perception that occur during a period of critical care can seriously impact on health and nutritional status, activities of daily living, independence, quality of life and the possibility of recovery. It is emphasized from the outset that sensory losses in critically-ill patients may or may not be related to their current medical condition. The present paper provides an overview of all five senses (vision, hearing, taste, smell and touch) and describes the factors that contribute to sensory losses in critically-ill patients, including medications, medical conditions and treatments and the process of aging itself. Cancer and stroke are two critical illnesses in which profound sensory decrements often occur. Many sensory complaints in patients with cancer are related to alteration in sensory signals caused by damage to the sensory receptors. However, some complaints, such as taste aversions in patients with cancer, are not related to altered sensory physiology per se but to learned aversions that arise during the noxious effects of radiotherapy and chemotherapy. The paper also reviews a study in which the sensory performance (of all five senses) was compared in three groups of elderly subjects: (1) patients who had undergone coronary artery bypass surgery; (2) patients with cardiovascular conditions but with no history of surgery; (3) healthy non-medicated age-matched controls. Performance of patients who had undergone coronary artery bypass surgery was worse than that for the other two groups, with taste and smell losses greater than for the other senses. The study demonstrates that critical illness (e.g. coronary artery bypass surgery) can exacerbate sensory losses in an older cohort. PMID:17637085
A 67-year-old man complained of impaired vision at night for several months. He was known to have arcus senilis (arcus lipoides corneae) since aged 21 years. For the last 20 years both corneas had become progressively more cloudy. His mother was said to have had similar eye changes. Ophthalmological examination discovered no abnormality other than marked corneal dystrophy with hardly separable arcus senilis. General physical examination was normal. Total cholesterol and triglyceride levels in serum were within normal limits, but serum concentration of high density lipoprotein (HDL) cholesterol (8 mg/dl) was reduced as were, within the high density lipoprotein fraction, the concentrations of triglyceride (4 mg/dl), phospholipids (38 mg/dl), the proportion of cholesterol esters (31%), and the cholesterol-esterification rate (51 nmol/ml . h). The HDL-associated activity of lecithin-cholesterol-acetyltransferase activity was scarcely measurable (0.9 nmol/ml . h). The signs in this case (cloudy cornea, marked decrease in serum HDL cholesterol concentration without premature arteriosclerosis) are typical of fish eye disease. PMID:7924949
Schmidt, H H; Diekstall, F F; Bojanovski, D; Manns, M P
The prevalence of obesity has reached epidemic proportions in many countries. While its impact on overall health is well documented, less is known about the ocular manifestations of obesity. Amongst different eye diseases, obesity has been linked with age-related cataract, glaucoma, age-related maculopathy, and diabetic retinopathy. Numerous population-based and prospective studies support an association between obesity and risk of age-related cataract. However, the nature and strength of these associations, particularly with the different cataract subtypes, remains to be determined. There is strong evidence that obesity is associated with elevated intraocular pressure, but there is no convincing data to support a more direct association between obesity and glaucomatous optic neuropathy. Studies to date have not found a consistent pattern of association between obesity and risk of age-related maculopathy or diabetic retinopathy. Thus, while obesity may be a risk factor for many ocular conditions, the present literature is inadequate to establish any convincing associations. Furthermore, whether weight loss reduces the risk of eye diseases remains unresolved. Because of the potential public health impact of obesity, there is a greater need to understand its ocular effects.
Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD. PMID:22569356
This paper studies algorithmic aspects of majority domina- tion, which is a variation of domination in graph theory. A majority dominating function of a graph G = (V;E) is a function g from V to f¡1;1g such that P u2N(v) g(u) ‚ 1 for at least half of the vertices v 2 V. The majority domination problem is to find
Propriospinal pathways are thought to be critical for quadrupedal coordination by coupling cervical and lumbar central pattern generators (CPGs). However, the mechanisms involved in relaying information between girdles remain largely unexplored. Using an in vitro spinal cord preparation in neonatal rats, Juvin and colleagues (Juvin et al. 2012) have recently shown sensory inputs from the hindlimbs have greater influence on forelimb CPGs than forelimb sensory inputs on hindlimb CPGs, in other words, a bottom-up control system. However, results from decerebrate cats suggest a top-down control system. It may be that both bottom-up and top-down control systems exist and that the dominance of one over the other is task or context dependent. As such, the role of sensory inputs in controlling quadrupedal coordination before and after injury requires further investigation. PMID:22514293
Purpose We developed a near ocular dominance test modeled after the distance hole-in-the card test, and assessed both test-retest reliability of four tests of ocular dominance and agreement between tests. Methods 46 subjects ages 18 to 78 years with visual acuity 20/40 or better in each eye were enrolled from a primary care practice. All subjects had normal eye examinations, with the exception of refractive error, and were examined in their habitual correction. Subjects were tested twice each with the distance hole-in-the-card test, new near hole- in-the-card test, near convergence test, and the Pediatric Eye Disease Investigator Group (PEDIG) fixation preference test. Test-retest reliability and agreement between tests were evaluated with the Kappa statistic. Results There was substantial to almost perfect test-retest reliability for the distance hole-in-the-card test, new near hole-in-the-card test, convergence test, and PEDIG fixation preference test (Kappa, k=0.77, 0.62, 0.84, 0.77, respectively). In contrast, the agreement between the new near hole in the card test and the other three tests – distance hole in the card, near convergence, and PEDIG fixation preference– was moderate to slight (k=0.41, 0.19, 0.11, respectively). Agreement was moderate to fair (k=0.47, 0.32) between the distance hole in the card test and the near convergence test, and between the distance-hole-in-the-card test and the PEDIG fixation preference test. Agreement was fair (k=0.27) between the near convergence test and the PEDIG fixation preference test. Conclusions Although there was excellent test-retest reliability of each ocular dominance test, there was only moderate to slight agreement between tests. Results of ocular dominance tests seem to vary depending on both the testing distance and the specific activity performed as part of the testing procedure.
Rice, Melissa L.; Leske, David A.; Smestad, Christina E.; Holmes, Jonathan M.
Farmworkers face a variety of risk factors for eye injuries. Measures of eye protection use and of eye safety knowledge and beliefs are based on a survey of 300 Latino farmworkers in North Carolina. Few farmworkers report using eye protection (8.3%); most (92.3%) report that employers do not provide eye protection. Approximately 70% report that they are not trained in
Amit Verma; Mark R. Schulz; Sara A. Quandt; Erin N. Robinson; Joseph G. Grzywacz; Haiying Chen; Thomas A. Arcury
The purpose of this review is to consider new sensory rehabilitation avenues in the context of the brain's remarkable ability to reorganize itself following sensory deprivation. Here, deafness and blindness are taken as two illustrative models. Mainly, two promising rehabilitative strategies based on opposing theoretical principles will be considered: sensory substitution and neuroprostheses. Sensory substitution makes use of the remaining intact senses to provide blind or deaf individuals with coded information of the lost sensory system. This technique thus benefits from added neural resources in the processing of the remaining senses resulting from crossmodal plasticity, which is thought to be coupled with behavioral enhancements in the intact senses. On the other hand, neuroprostheses represent an invasive approach aimed at stimulating the deprived sensory system directly in order to restore, at least partially, its functioning. This technique therefore relies on the neuronal integrity of the brain areas normally dedicated to the deprived sense and is rather hindered by the compensatory reorganization observed in the deprived cortex. Here, we stress that our understanding of the neuroplastic changes that occur in sensory-deprived individuals may help guide the design and the implementation of such rehabilitative methods. PMID:21741554
Grechetto is a traditional white-grape vine, widespread in Umbria and Lazio regions in central Italy. Despite the wine commercial diffusion, little literature on its sensory characteristics is available. The present study is an exploratory research conducted with the aim of identifying the sensory markers of Grechetto wine and of evaluating the effect of clone, geographical area, vintage and producer on sensory attributes. A qualitative sensory study was conducted on 16 wines, differing for vintage, Typical Geographic Indication, and clone, collected from 7 wineries, using a trained panel in isolation who referred to a glossary of 133 white wine descriptors. Sixty-five attributes identified by a minimum of 50% of the respondents were submitted to a correspondence analysis to link wine samples to the sensory attributes. Seventeen terms identified as common to all samples are considered as characteristics of Grechetto wine, 10 of which olfactory: fruity, apple, acacia flower, pineapple, banana, floral, herbaceous, honey, apricot and peach. In order to interpret the relationship between design variables and sensory attributes data on 2005 and 2006 wines, the 28 most discriminating descriptors were projected in a principal component analysis. The first principal component was best described by olfactory terms and the second by gustative attributes. Good reproducibility of results was obtained for the two vintages. For one winery, vintage effect (2002-2006) was described in a new principal component analysis model applied on 39 most discriminating descriptors, which globally explained about 84% of the variance. In the young wines the notes of sulphur, yeast, dried fruit, butter, combined with herbaceous fresh and tropical fruity notes (melon, grapefruit) were dominant. During wine aging, sweeter notes, like honey, caramel, jam, become more dominant as well as some mineral notes, such as tuff and flint. PMID:20103144
An experiment was conducted on the effect of a prototype see-thru head-mounted display (HMD) on visuo-motor adaptation. When wearing video see-thru HMDs in augmented reality systems, subjects see the world around them through a pair of head-mounted video cameras. The study looked at the effects of sensory rearrangement caused by a HMD design that displaces the user's “virtual” eye position
J. P. Rolland; F. A. Biocca; T. Barlow; Anantha Kancherla
To make fast and accurate behavioral choices, we need to integrate noisy sensory input, take prior knowledge into account, and adjust our decision criteria. It was shown previously that in two-alternative-forced-choice tasks, optimal decision making can be formalized in the framework of a sequential probability ratio test and is then equivalent to a diffusion model. However, this analogy hides a “chicken and egg” problem: to know how quickly we should integrate the sensory input and set the optimal decision threshold, the reliability of the sensory observations must be known in advance. Most of the time, we cannot know this reliability without first observing the decision outcome. We consider here a Bayesian decision model that simultaneously infers the probability of two different choices and at the same time estimates the reliability of the sensory information on which this choice is based. We show that this can be achieved within a single trial, based on the noisy responses of sensory spiking neurons. The resulting model is a non-linear diffusion to bound where the weight of the sensory inputs and the decision threshold are both dynamically changing over time. In difficult decision trials, early sensory inputs have a stronger impact on the decision, and the threshold collapses such that choices are made faster but with low accuracy. The reverse is true in easy trials: the sensory weight and the threshold increase over time, leading to slower decisions but at much higher accuracy. In contrast to standard diffusion models, adaptive sensory weights construct an accurate representation for the probability of each choice. This information can then be combined appropriately with other unreliable cues, such as priors. We show that this model can account for recent findings in a motion discrimination task, and can be implemented in a neural architecture using fast Hebbian learning.
Active inference provides a simple and neurobiologically plausible account of how action and perception are coupled in producing (Bayes) optimal behaviour. This can be seen most easily as minimising prediction error: we can either change our predictions to explain sensory input through perception. Alternatively, we can actively change sensory input to fulfil our predictions. In active inference, this action is mediated by classical reflex arcs that minimise proprioceptive prediction error created by descending proprioceptive predictions. However, this creates a conflict between action and perception; in that, self-generated movements require predictions to override the sensory evidence that one is not actually moving. However, ignoring sensory evidence means that externally generated sensations will not be perceived. Conversely, attending to (proprioceptive and somatosensory) sensations enables the detection of externally generated events but precludes generation of actions. This conflict can be resolved by attenuating the precision of sensory evidence during movement or, equivalently, attending away from the consequences of self-made acts. We propose that this Bayes optimal withdrawal of precise sensory evidence during movement is the cause of psychophysical sensory attenuation. Furthermore, it explains the force-matching illusion and reproduces empirical results almost exactly. Finally, if attenuation is removed, the force-matching illusion disappears and false (delusional) inferences about agency emerge. This is important, given the negative correlation between sensory attenuation and delusional beliefs in normal subjects-and the reduction in the magnitude of the illusion in schizophrenia. Active inference therefore links the neuromodulatory optimisation of precision to sensory attenuation and illusory phenomena during the attribution of agency in normal subjects. It also provides a functional account of deficits in syndromes characterised by false inference and impaired movement-like schizophrenia and Parkinsonism-syndromes that implicate abnormal modulatory neurotransmission. PMID:23744445
Brown, Harriet; Adams, Rick A; Parees, Isabel; Edwards, Mark; Friston, Karl
This study shows that, in a population of microstrabic patients (N = 76), a regain of a normal stereoscopy was possible in 19.6 of the cases (14 cases). Of these patients, 14 were hyperopic. With the full hyperopic correction, the angle of deviation on the alternate cover test was 0.45 PD (range: 0 to 3 PD). Without correction the deviation increased to between 3 PD and 10 PD (mean: 6.3 PD). Ten patients presented an anisometropia between 0.75 D to 2.50 D. (mean: 1.4 D). All anisometropic patients were hyperopic and hyperopia was higher in the dominatedeye in all these cases. These results demonstrate the interest of the definition of microtropia as a specific strabismological entity, which can be congenital or acquired and be influenced by accommodative factors. The incidence of anisometropia, as a consequence rather than a cause of the pathological dominance is discussed. PMID:10546381
In this paper we investigate the epochs in which the Universe started accelerating and when it began to become dark energy dominated (i.e., the dynamics of the expansion of the Universe dominated by the dark energy). We provide analytic expressions to calculate the redshifts of these epochs as a function of density parameters. Moreover, we review and discuss cosmological models
When two or more cultural groups make contact and interact over a period of time, language dominance often occurs. In this situation, one dominates the others both culturally and linguistically. This in turn, causes the weaker to start using the language of the more powerful until eventually it shifts its language and then its culture over to that of the
|Numerous areas associated with brain dominance have been researched since Bogen and Sperry's work with split-brain patients in the 1960s, but only slight attention has been given to the connection between brain dominance and personality. No study appears in the literature seeking to understand optimal mental health as defined by Maslow's…
Dealing with the NP-complete Dominating Set problem on graphs, we demonstrate the power of data reduction by preprocessing from a theoretical as well as a practical side. In particular, we prove that Dominating Set restricted to planar graphs has a so-called problem kernel of linear size, achieved by two simple and easy to implement reduction rules. Moreover, having implemented our
Jochen Alber; Michael R. Fellows; Rolf Niedermeier
Honey bee dance language is a unique and complex form of animal communication used to inform nest mates in the colony about the specific location of food sources or new nest sites. Five different sensory systems have been implicated in acquiring and communicating the information necessary for dance language communication. We present results from neuronal tracer studies identifying the central projections from four of the five. Sensory neurons of the dorsal rim area of the compound eyes, involved in acquiring sun-compass based information, project to the dorsal-most part of the medulla. Sensory neurons of the neck hair plates, required to transpose sun-compass based information to gravity-based information in the dark hive, project to the dorsal labial neuromere of the subesophageal ganglion. Sensory neurons from the antennal joint hair sensilla and the Johnston's organ, which perceive information on dance direction and distance from mechanostimuli generated by abdomen waggling and wing vibration, project to the deutocerebral dorsal lobe and the subesophageal ganglion, and the posterior protocerebrum, respectively. We found no 'dance-specific' projections relative to those previously described for drone and queen honey bees and other insect species that do not exhibit dance communication. We suggest that the evolution of dance language communication was likely based on the modification of central neural pathways associated with path integration, the capability to calculate distance, and directional information during flight. PMID:17519525
Hormonal, metabolic, hemodynamic, vascular and immunological changes that occur during pregnancy can affect the function of the eye. These changes are commonly transient, but in some cases they may be permanent and have consequences even after childbirth. The ocular effects of pregnancy may be physiological or pathological and can be associated with the development of new ocular pathology or may be modifications of pre-existing conditions. The most common physiological changes are alterations of corneal sensitivity and thickness, decreased tolerance to contact lenses, decreased intraocular pressure, hemeralopia and refractive errors. Possible posterior segment changes include worsening of diabetic retinopathy, central serous chorioretinopathy, increased risk of peripheral vitreochorioretinal dystrophies and retinal detachment. Thus, it should be kept in mind that the presence of any ocular symptoms in a pregnant woman requires ophthalmologic examination and further management. PMID:23837242
Gotovac, Marta; Kastelan, Snjezana; Lukenda, Adrian
How does an institution help tell the story of the community it is located in? This type of endeavor can take many approaches, and the University of Arizona seems to have found a fantastic way to do so. Working with a variety of organizations and individuals throughout the greater Tucson and Southern Arizona community. Through Our Parents' Eyes: History & Culture of Southern Arizona was started in the mid-1990s. The project was designed to bring together the diverse human experiences of the region by drawing on a wide range of documents, oral histories, historic images, and video clips. The project and this website feature a number of teaching resources, regional histories, and primary documents for use by anyone interested in the region. Some of these resources have been collected into thematic presentations, including "Words & Place: Native Literature of the American Southwest" and "War Relocation Authority Camps in Arizona, 1942-1946".
Over the past century, compound eyes in nature have been one of the most studied and intriguing topics in physiological optics due to their unique optical scheme for imaging. Hundreds to ten thousands of integrated optical units called ommatidia are spherically arranged along a curvilinear surface and point in different directions. Each ommatidium collects light within a small angular acceptance and collectively they construct a full image with a wide field-of-view. In this work, artificial compound eye lenses with three-dimensional configuration, which are anatomically and functionally similar to those in nature, have been synthesized using a photosensitive polymer resin by utilizing microlens technology, self-written waveguide process, and soft lithography. Replicated honeycomb packed polymer microlenses as substitute for facet lenses in a natural compound eye was microfabricated with a photoresist melting process for microlens templates and a soft lithographic process for polymer replication. The microtemplate of photoresist microlens arrays (F/1 ˜ F/3, DL = 20 ˜ 50 mum) with low Fresnel number (NF < 10) and high packing density was replicated with different polymers such as UV curable epoxy resin, polydimethylsiloxane elastomer, and a negative tone photoresist. Related to ommatidial optics, the diffraction of a low Fresnel number microlens, the light guiding of a waveguide, and the angular acceptance function of a microlens-waveguide system were theoretically studied with numerical analysis. First, as a prototype microfabricated microlens-waveguide system ( DL = 300 mum), a small angular acceptance (rho A = 1.5°) comparable to that of natural ommatidia was experimentally achieved and compared with the numerical analysis. The system is based on self-written waveguides in a photosensitive polymer resin and replicated elastomer microlens arrays. However, due to the technical difficulties in handling the elastomer membrane with microlenses, it is limited in scaling down to the physical dimensions of natural ommatidium. Second, as an advanced development, self-aligned microlens-waveguide systems comparable to the physical dimensions of natural ommatidia have been developed and integrated in a photosensitive resin. The individual microlens-waveguide systems of about 8,370 were spherically arranged along the circumference of a polymer dome of 2.5 mm in diameter and each points in different directions. The spherical configuration was realized using a replication process of reconfigurable microtemplates, i.e. the polymer replication using the deformed elastomer membrane with microlens patterns under small pressure (5 kPa ˜ 20 kPa). The characterizations of the small scale microlenses (F/1.8 ˜ F/2.9, DL = 25 mum) and waveguides were also carried out with a modified reflection/transmission confocal microscope. The comparative discussion between natural and artificial compound eyes is described and several future directions based on this work are also proposed.
The wonderful Eye of Science project began in 1994, and is currently under the direction of Oliver Meckes and Nicole Ottawa. As their philosophic statement on this website states, "Our aim is to combine scientific exactness with aesthetic appearances, and thereby help to bridge the gap between the world of science and the world of art." In order to help serve this mission, they have placed numerous examples of their work online in a series of galleries on this site. Using electron microscopy and a host of other equipment and techniques, the pair has created these fine images of such things as parasites, cross-sections of a lavender leaf, and a rather harrowing photograph of an itch mite. Along with viewing these images, visitors can also learn about the awards they have received and learn about the equipment they use in their work.
Opinion statement No current disease-modifying treatments have been shown definitively in randomized clinical trials to reduce or reverse diabetic sensory polyneuropathy (DSP). It is increasingly recognized that individuals with “prediabetes” or impaired glucose regulation can already have a “small-fiber” neuropathy, or mild DSP, in which sensory axons of both small and larger diameter are damaged. Small-fiber neuropathy is frequently associated with pain, and these patients may present to a neurologist for evaluation before the underlying glucose dysregulation has been diagnosed. It is important to identify these individuals, because aggressive diabetic control and lifestyle interventions can delay the onset of diabetes and may reverse small-fiber neuropathy associated with early diabetes mellitus. Although treatment currently focuses on pain associated with DSP, attention should be paid to potential risk factors for neuropathy. For example, glycemic control and hyperlipidemia should be improved with diet, exercise, and medications. Hypertension that is a risk marker for more severe neuropathy should be treated. Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers not only treat hypertension but also may directly reduce the progression of neuropathy. Class I or II clinical studies support the use of sodium valproate, pregabalin, duloxetine, amitriptyline, gabapentin, venlafaxine, opioids, and topical capsaicin in treating diabetic neuropathic pain. Pregabalin and gabapentin are relatively well tolerated and have few medication interactions. Sodium valproate has been shown to be effective but is not recommended for use in women of childbearing potential, and patients must be monitored for hepatotoxicity and thrombocytopenia. Tricyclic antidepressants such as amitriptyline are often used for nocturnal pain but require caution in the elderly or anyone with cardiac disease. Venlafaxine and duloxetine successfully treat neuropathic pain independently of their effect on depression. Opioid medications are associated with a high rate of adverse effects but with careful monitoring, they can be effective in treating resistant neuropathic pain. Capsaicin is an effective topical treatment that lacks systemic side effects. The lidocaine patch is effective in relieving pain associated with postherpetic neuralgia, but only class III evidence supports its use for diabetic neuropathic pain. No current Class I or II studies support other treatment modalities.
The selective advantages of using light as a source of information are reflected in the diverse types of extant eyes. The physical properties of light restrict how it can be collected and processed, resulting in only eight known optical systems found in animals. Eyes develop through tissue rearrangement and differentiation. Our understanding of the source of genetic information used in
Human hair and eye color is unusually diverse in northern and eastern Europe. The many alleles involved (at least seven for hair color) and their independent origin over a short span of evolutionary time indicate some kind of selection. Sexual selection is particularly indicated because it is known to favor color traits and color polymorphisms. In addition, hair and eye
This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field
Eleven thousand eye injuries are suffered annually by 5- to-14-year-old youngsters during sports and recreational activities. Baseball-related accidents result in more eye injuries to youth than any other sport. Protective face gear is discussed and recommended. (MT)
A baseline visual acuity should be on record for medical and legal purposes. Identifying an eye injury and referring the person for appropriate treatment can save vision. Immediate eye irrigation in the case of chemical burns can substantially decrease the possibility of permanent vision damage.
An amblyopia, or lazy eye, is an eye that is healthy in all respects but which has defective vision, even after the fitting of correcting lenses for a refractive error. Amblyopia can be a strongly hereditary condition. The author describes the predisposing conditions and discusses methods of assessment and the effectiveness of its present treatment. PMID:7625935
Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.
Eighty-five million years ago on small planet Earth, dinosaurs ruled, ignorant of their soon-to-come demise in the great Jurassic extinction, while mammals were still small and shy creatures. The southern Andes of Bolivia, Chile, and Argentina were not yet formed and South America was still an island continent. Eighty-five million years ago, our Sun and its solar system was 60,000 light years away from where it now stands . Eighty-five million years ago, in another corner of the Universe, light left the beautiful spiral galaxy NGC 1350, for a journey across the universe. Part of this light was recorded at the beginning of the year 2000 AD by ESO's Very Large Telescope, located on the 2,600m high Cerro Paranal in the Chilean Andes on planet Earth. Astronomers classify NGC 1350 as an Sa(r) type galaxy, meaning it is a spiral with large central regions. In fact, NGC 1350 lies at the border between the broken-ring spiral type and a grand design spiral with two major outer arms. It is about 130,000 light-years across and, hence, is slightly larger than our Milky Way. The rather faint and graceful outer arms originate at the inner main ring and can be traced for almost half a circle when they each meet the opposite arm, giving the impression of completing a second outer ring, the "eye". The arms are given a blue tint as a result of the presence of very young and massive stars. The amount of dust, seen as small fragmented dust spirals in the central part of the galaxy and producing a fine tapestry that bear resemblance with blood vessels in the eye, is also a signature of the formation of stars.
Monocular deprivation (MD) during the critical period (CP) shifts ocular dominance (OD) of cortical responsiveness toward the nondeprived eye. The synaptic mechanisms underlying MD-induced OD plasticity, in particular the contribution of cortical inhibition to the plasticity, have remained unsolved. In this study, using in vivo whole-cell voltage-clamp recordings, we revealed eye-specific excitatory and inhibitory synaptic inputs to layer 4 excitatory neurons in mouse primary visual cortex (V1) at a developmental stage close to the end of CP. We found in normally reared mice that ocular preference is primarily determined by the contralateral bias of excitatory input and that inhibition does not play an active role in shaping OD. MD results in a parallel reduction of excitation and inhibition driven by the deprived eye, while reducing the inhibition but preserving the excitation driven by the nondeprived eye. MD of longer periods causes larger changes in synaptic amplitude than MD of shorter periods. Furthermore, MD resulted in a shortening of onset latencies of synaptic inputs activated by both contralateral and ipsilateral eye stimulation, while the relative temporal relationship between excitation and inhibition driven by the same eye was not significantly affected. Our results suggest that OD plasticity is largely attributed to a reduction of feedforward input representing the deprived eye, and that an unexpected weakening of cortical inhibitory connections accounts for the increased responsiveness to the nondeprived eye. PMID:23825430
A death-related sensory experience (DRSE) is a spiritually transforming experience occurring with the appearance of a messenger beyond the visible observable universe to guide a dying person through the dying process. DRSEs have been reported to occur among those who are dying, most commonly individuals with terminal illness. Known dead family members are most commonly seen, followed by religious beings. Communication takes place between the dying individual and the apparition. Feelings of peace and comfort are reported by the majority of individuals experiencing DRSEs. DRSEs can occur over a period of hours to months before death. They have been referred to as veridical hallucinations, visions of the dying, deathbed visions, and predeath visions. Reported throughout time, among people of all cultures, religions, races, ages, genders, socioeconomic status, and educational levels, DRSEs are intense spiritual experiences. Validating a child's DRSE provides a way to start a dialogue regarding death. Research is needed to more fully understand DRSEs from the perspective of the dying child. PMID:15695352
... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Fish-eye disease On this page: Description Genetic changes ... names Glossary definitions Reviewed August 2013 What is fish-eye disease? Fish-eye disease, also called partial ...
The arms play an important role in balance regulation during walking. In general, perturbations delivered during walking trigger whole-body corrective responses. For instance, holding to stable handles can largely attenuate and even suppress responses in the leg muscles to perturbations during walking. Particular attention has been given to the influence of light touch on postural control. During standing, lightly touching a stable contact greatly reduces body sway and enhances corrective responses to postural perturbations, whereas light touch during walking allows subjects to continue to walk on a treadmill with the eyes closed. We hypothesized that in the absence of mechanical support from the arms, sensory cues from the hands would modulate responses in the legs to balance disturbing perturbations delivered at the torso during walking. To test this, subjects walked on a treadmill while periodically being pulled backwards at the waist while walking. The amplitude of the responses evoked in tibialis anterior to these perturbations was compared across 4 test conditions, in a 2 × 2 design. Subjects either (a) lightly touched or (b) did not touch a stable contact, while the eyes were (c) open or (d) closed. Allowing the subjects to touch a stable contact resulted in a reduction in the amount of fore-aft oscillation of the body on the treadmill, which was accompanied by a reduction in the ongoing electromyographic activity in both tibialis anterior and soleus during undisturbed walking. In contrast, the provision of touch resulted in an increase in the amplitude of the evoked responses in tibialis anterior to the backward perturbations that was more evident when subjects walked with the eyes closed. These results indicate that light touch provides a sensory cue that can be used to assist in stabilizing the body while walking. In addition, the sensory information provided by light touch contributes to the regulation of corrective reactions initiated by balance disturbances encountered during walking. PMID:23483209
Sensory illusions in hang-gliding and para-gliding. Hang-gliding and para-gliding are at the moment booming sports. Sensory illusions are physiological phenomena sharing the wrong perception of the pilote's real position in space. These phenomena are very familiar to aeroplane pilotes, they can also be noticed on certain conditions with hang-gliding pilotes. There are many and various sensory illusions, but only illusions of vestibular origin will be dealt with in this article. Vestibular physiology is reminded with the working principle of a semicircular canal. Physiology and laws of physics explain several sensory illusions, especially when the pilote loses his visual landmarks: flying through a cloud, coriolis effect. Also some specific stages of hang-gliding foster those phenomena: spiraling downwards, self-rotation, following an asymetric closing of the parachute, spin on oneself. Therefore a previous briefing for the pilotes seems necessary. PMID:9687650
The overall goals of this research project are to longitudinally quantify deficits in the maintenance of dynamic stability during locomotion and in sensory motor functions of individuals following a concussion and to establish recovery curves of these mea...
This report reviews presentations at the symposium on Drugs and Sensory Functions, held 23-24 Mar 1966 at the Royal College of Physicians, London, which was supported by six British and two international scientific organizations. Approximately 250 attende...
Polymodal sensory neurons inform organisms about the nature of the physical world around them. The activity of these cells guide behaviors including the withdrawal from nocifensive stimuli such as intense heat or harsh force to feeling the comforting weight of a warm blanket. Molecular and genetic analysis of the channel proteins required for these divers behavioral responses have revealed an elaborate and disparate collection of channel proteins within the polymodal sensory neuron. Recent data supports that the biophysical traits of the channel proteins combined with the collection of channels activated during stimulation is sufficient to describe the nature of the stimulus. It is currently unclear what the functional arrangement of channel proteins are during perception. Specifically, are channel proteins arranged in parallel and function independently during perception, or are these channel proteins arranged in functional sensory networks. We propose a hierarchal functional arrangement of channels within polymodal sensory neurons that incorporates aspects of both parallel and serial arrangements of channel proteins.
Explicit (often verbal) reports are typically used to investigate memory (e.g. "Tell me what you remember about the person you saw at the bank yesterday."), however such reports can often be unreliable or sensitive to response bias 1, and may be unobtainable in some participant populations. Furthermore, explicit reports only reveal when information has reached consciousness and cannot comment on when memories were accessed during processing, regardless of whether the information is subsequently accessed in a conscious manner. Eye movement monitoring (eye tracking) provides a tool by which memory can be probed without asking participants to comment on the contents of their memories, and access of such memories can be revealed on-line 2,3. Video-based eye trackers (either head-mounted or remote) use a system of cameras and infrared markers to examine the pupil and corneal reflection in each eye as the participant views a display monitor. For head-mounted eye trackers, infrared markers are also used to determine head position to allow for head movement and more precise localization of eye position. Here, we demonstrate the use of a head-mounted eye tracking system to investigate memory performance in neurologically-intact and neurologically-impaired adults. Eye movement monitoring procedures begin with the placement of the eye tracker on the participant, and setup of the head and eye cameras. Calibration and validation procedures are conducted to ensure accuracy of eye position recording. Real-time recordings of X,Y-coordinate positions on the display monitor are then converted and used to describe periods of time in which the eye is static (i.e. fixations) versus in motion (i.e., saccades). Fixations and saccades are time-locked with respect to the onset/offset of a visual display or another external event (e.g. button press). Experimental manipulations are constructed to examine how and when patterns of fixations and saccades are altered through different types of prior experience. The influence of memory is revealed in the extent to which scanning patterns to new images differ from scanning patterns to images that have been previously studied 2, 4-5. Memory can also be interrogated for its specificity; for instance, eye movement patterns that differ between an identical and an altered version of a previously studied image reveal the storage of the altered detail in memory 2-3, 6-8. These indices of memory can be compared across participant populations, thereby providing a powerful tool by which to examine the organization of memory in healthy individuals, and the specific changes that occur to memory with neurological insult or decline 2-3, 8-10.
Ryan, Jennifer D.; Riggs, Lily; McQuiggan, Douglas A.
Two experiments were performed to investigate the effect of noradrenaline (NA) depletion following systemic administration of the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine ( DSP4; 50 mg\\/kg, ip) on sensory preconditioning in the rat. For sensory preconditioning, a taste (saccharin, CS 2) and a special type of drinking bottle (noisy bottle) were paired during Phase 1. During Phase 2, the noisy bottle (CS 1)
An integrated computational approach to modeling sensory systems which couples realistic layered neural models of sensory cortex and midbrain nuclei to detailed models of the sense organs (e.g., retina or cochlea) is described. The approach is applied to the auditory system. Through an exercise of the model, it is shown that spatial location of sounds may be a natural consequence of the way cochlear response is mapped onto the cortex. 31 refs., 23 figs., 3 tabs.
When formulating an estimate of event time, the human sensory system has been shown to possess a degree of perceptual flexibility.\\u000a Specifically, the perceived relative timing of auditory and visual stimuli is, to some extent, a product of recent experience.\\u000a It has been suggested that this form of sensory recalibration may be peculiar to the audiovisual domain. Here we investigate
The synthesis and sensory evaluation of enantiomeric sets of sedanenolide (1) and 3-butylphthalide (3) are described. The asymmetric synthesis was achieved via the intramolecular Diels-Alder reaction of chiral propargylester (5) which was prepared from optically active propargyl alcohol (4) and 2,4-pentadienoic acid. The sensory evaluation of these enantiomers revealed that there were distinct differences between their aroma character and odor threshold. PMID:21821949
Farmworkers face a variety of risk factors for eye injuries. Measures of eye protection use and of eye safety knowledge and beliefs are based on a survey of 300 Latino farmworkers in North Carolina. Few farmworkers report using eye protection (8.3%); most (92.3%) report that employers do not provide eye protection. Approximately 70% report that they are not trained in preventing eye injuries; 81% believe that their chances of getting an eye injury are low. Many farmworkers choose to take risks in order to save time. Interventions are needed that target farmworker knowledge and beliefs about eye safety.
Verma, Amit; Schulz, Mark R.; Quandt, Sara A.; Robinson, Erin N.; Grzywacz, Joseph G.; Chen, Haiying; Arcury, Thomas A.
Sensory plasticity, whereby individuals compensate for sensory deprivation in one sense by an improvement in the performance of an alternative sense, is a well-documented phenomenon in nature. Despite this, the behavioural and ecological consequences of sensory plasticity have not been addressed. Here we show experimentally that some components (vision and chemoreception) of the sensory system of guppies are developmentally plastic, and that this plasticity has important consequences for foraging behaviour. Guppies reared under low light conditions had a significantly stronger response to chemical food cues encountered in isolation than fish reared at higher light levels. Conversely, they exhibited a weaker response to visual-only cues. When visual and olfactory/gustatory cues were presented together, no difference between the strength of response for fish reared at different light intensities was evident. Our data suggest that guppies can compensate for experience of a visually poor, low light environment via a sensory switch from vision to olfaction/gustation. This switch from sight to chemoreception may allow individuals to carry out the foraging behaviour that is essential to their survival in a visually poor environment. These considerations are especially important given the increasing frequency of anthropogenic changes to ecosystems. Compensatory phenotypic plasticity as demonstrated by our study may provide a hitherto unconsidered buffer that could allow animals to perform fundamental behaviours in the face of considerable change to the sensory environment.
Chapman, Ben B.; Morrell, Lesley J.; Tosh, Colin R.; Krause, Jens
AIM To report various ocular lesions caused by accidental instillation of superglue. METHODS Three cases of ocular injuries are described in children aged 6 years, 3 years and 8 months, following accidental instillation of superglue in the eye. RESULTS In the first case there was sticking of eyelashes in the medial 1/3 of eyelids in both eyes. In the second case sticking of eye lashes was present in the lateral 1/3 of eyelids in the left eye. In the third case, superglue was present on the right cheek, above the right ear and sticking of eyelids in medial 1/3 in right eye. The eyelids were separated by pulling the lid margins with fingers in the first case and later on superglue was removed by trimming the eyelashes; and by direct trimming the eyelashes in second and third cases. There was no injury to other structures of anterior segment in the first two cases. However, removal of the superglue on the cornea resulted in corneal abrasion in the third case which healed with medical treatment and patching of the right eye. CONCLUSION Accidental instillation of superglue is possible because of the appearance of the tube like eye ointment tube. Immediate medical aid will prevent ocular morbidity.
The ‘division of labour’ model of eye evolution is elaborated here. We propose that the evolution of complex, multicellular animal eyes started from a single, multi-functional cell type that existed in metazoan ancestors. This ancient cell type had at least three functions: light detection via a photoreceptive organelle, light shading by means of pigment granules and steering through locomotor cilia. Located around the circumference of swimming ciliated zooplankton larvae, these ancient cells were able to mediate phototaxis in the absence of a nervous system. This precursor then diversified, by cell-type functional segregation, into sister cell types that specialized in different subfunctions, evolving into separate photoreceptor cells, shading pigment cells (SPCs) or ciliated locomotor cells. Photoreceptor sensory cells and ciliated locomotor cells remained interconnected by newly evolving axons, giving rise to an early axonal circuit. In some evolutionary lines, residual functions prevailed in the specialized cell types that mirror the ancient multi-functionality, for instance, SPCs expressing an opsin as well as possessing rhabdomer-like microvilli, vestigial cilia and an axon. Functional segregation of cell types in eye evolution also explains the emergence of more elaborate photosensory–motor axonal circuits, with interneurons relaying the visual information.
Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity Hp(0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity Hp(3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of Hp(0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of Hp(3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of Hp(0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.
|Theory and research on the relation of lateral dominance to the causation of reading disability are reviewed. Both direct and indirect measures of cerebral hemisphere functioning are considered. (SBH)|
A myriad of mechanisms are suggested to account for the full richness of visual cortical plasticity. We report that visual cortex lacking Arc is impervious to the effects of deprivation or experience. Using intrinsic signal imaging and chronic visually evoked potential recordings, we find that Arc?/? mice do not exhibit depression of deprived eye responses or a shift in ocular dominance after brief monocular deprivation. Extended deprivation also fails to elicit a shift in ocular dominance or open eye potentiation. Moreover, Arc?/? mice lack stimulus–selective response potentiation. Although Arc?/? mice exhibit normal visual acuity, baseline ocular dominance is abnormal and resembles that observed after dark–rearing. These data suggest that Arc is required for the experience–dependent processes that normally establish and modify synaptic connections in visual cortex.
McCurry, Cortina L.; Shepherd, Jason D.; Tropea, Daniela; Wang, Kuan H.; Bear, Mark F.; Sur, Mriganka
In this paper, we propose a hybrid level set model with application to the segmentation of eye socket. Compared with other level set methods, the hybrid model is more robust and accurate due to the combination of region and boundary information. It solves the leaking problem of boundary based level set method. The segment results of hybrid level set model can be used in 3-D eye socket reconstruction and calculation of hydroxyapatite implant, which are useful in computer-aided surgery. Experiments have shown that hybrid level set model has very good performance in the segmentation of eye socket. PMID:16294712
This Website showcases materials from the recently published Simon & Schuster book, Eye of the Storm, which details in vivid watercolors, maps, and journal entries, events from the Civil War as witnessed by Union soldier Private Knox Sneden. The site offers 20 selections from Knox's diaries covering from 1861 to December of 1864, each accompanied by a watercolor or map viewable in two sizes, as well as four Flash presentations of these watercolors based around particular incidents Knox witnessed. The watercolors, while not masterpieces, are fine renderings of characteristic events of the war -- a surprise artillery attack by Rebels against an overconfident and underobservant Union fortification, a surrendering of 10,000 troops, views of battles, sabotage operations, and the like. More than anything, they give a sense of the harsh imprint of war upon an otherwise typically bucolic countryside. Knox's dark lines of soldiers, scarred earth, and flames reflected in slow running rivers show that America's bloodiest war touched not only its people, but its landscape as well.
Patterns of sensory abnormalities in children and adults with autism were examined using the Diagnostic Interview for Social\\u000a and Communication Disorders (DISCO). This interview elicits detailed information about responsiveness to a wide range of sensory\\u000a stimuli. Study 1 showed that over 90% of children with autism had sensory abnormalities and had sensory symptoms in multiple\\u000a sensory domains. Group differences between
Susan R. Leekam; Carmen Nieto; Sarah J. Libby; Lorna Wing; Judith Gould
Children with autism are frequently observed to experience difficulties in sensory processing. This study examined specific\\u000a patterns of sensory processing in 54 children with autistic disorder and their association with adaptive behavior. Model-based\\u000a cluster analysis revealed three distinct sensory processing subtypes in autism. These subtypes were differentiated by taste\\u000a and smell sensitivity and movement-related sensory behavior. Further, sensory processing subtypes
Unusual sensory processing has been widely reported in autism spectrum disorders (ASDs); however, the majority of research in this area has focused on children. The present study assessed sensory processing in adults with ASD using the Adult\\/Adolescent Sensory Profile (AASP), a 60-item self-report questionnaire assessing levels of sensory processing in everyday life. Results demonstrated that sensory abnormalities were prevalent in
ABSTRA C T Unusual sensory processing has been widely reported in autism spectrum disorders (ASDs); however, the majority of research in this area has focused on children. The present study assessed sensory processing in adults with ASD using the Adult\\/Adolescent Sensory Profile (AASP), a 60-item self-report questionnaire assessing levels of sensory processing in everyday life. Results demonstrated that sensory abnormalities
Existing research investigating interactions between visual and oral sensory cues has tended to use model food systems. In contrast, this study compared product quality assessments of corn-fed and wheat-fed chicken products among persons recruited in Northern Ireland. Three approaches have been adopted to investigate the effect of colour upon consumer choice of chicken: sensory assessment under normal lighting; focus group
Orla B. Kennedy; Barbara J. Stewart-Knox; Peter C. Mitchell; David I. Thurnham
Genes involved in eye development are highly conserved between vertebrates and Drosophila. Given the complex genetic network controlling early eye development, identification of regulatory sequences controlling gene expression will provide valuable insights toward understanding central events of early eye specification. We have focused on defining regulatory elements critical for Drosophila eyes absent (eya) expression. Although eya has a complex expression
Quang T. Bui; John E. Zimmerman; Haixi Liu; Gladys L. Gray-Board; Nancy M. Bonini
... clearly and for common daily tasks such as reading and driving. Nearly two million people have the advanced form of the disease, called wet AMD, which can cause rapid vision loss in both eyes. An early symptom ...
... Medical Director, Health Initiatives View full profile Pollen Allergy: Prevent Eye Irritation For many seasonal allergy sufferers, ... View Daily Pollen Count Receive Health-e-News Allergy Programs At National Jewish Health, some of the ...
BackgroundTourette syndrome is a stress-sensitive neurologic disorder characterized by involuntary vocal and motor tics. Both Tourette syndrome and the medical treatment for this condition can affect the eye.
... uvea, which includes the iris, ciliary body, and choroid (see “ What is eye cancer? ”). The T categories ... Tumor has grown into the ciliary body or choroid (or both). T2a: Tumor has grown into the ...
Both, the sensory organs themselves and the central nervous system with its decoding functions for perception of sensory stimuli influence drastically the human ability for social communication especially with respect to the exchange of speech information. Severe hearing loss, e. g., may inhibit the motivation for the continuation of existing social contacts considerably in aging human beings. Additionally the drop of elasticity within the eye's lense influences negatively the visual human interaction with increasing age. Similarly the performance of the somesthetic, the olfactory and the gustatory sensory may drop simultaneously. Since also the physiological conditions for information storage and retrieval are altered in the senium the wellknown social problems of aged people seem to be due rather to the central parts of the sensory channels than to the sensory organs per se. In this context it is of great importance for the avoidance of problems of the human interrelations between older subjects to keep the human brain intellectually trained as long as intensive as possible (E. Jalavisto). The neurophysiological changes within the CNS, therefore, are discussed in this paper as a function of age and in context with the more somato-physiological changes of the circulatory and metabolic processes including humoral, hormonal and biocybernetical transitions between the second and "Third" section of the human life. During senium, as a conclusion, emphasis should be given to the behavioral selection both of contact persons and of intellectual and emotionally loaded topics of interest to improve the quality of this last part of the life under the aspect that "multum" can be more than "multa", "universalistic" filtering of the life's events more than "encyclopedistic" knowledge (Th. Heuss). PMID:7467668
|In the public eye, three major investigations by the Federal Communications Commission (FCC) into the dominance of the broadcast networks have appeared as battles between opposing forces with lively conflicts as the FCC combats monopolistic power in the name of public interest. In spite of the past investigations and the resulting regulations,…
During development of the mammalian visual system, axon terminals of lateral geniculate nucleus (LGN) neurons, initially intermixed within layer 4 of the visual cortex, gradually segregate according to eye preference to form ocular dominance columns. In addition to LGN axons and layer 4 neurons, subplate neurons may also participate in interactions leading to column formation. Deletion of subplate neurons before
Volitional swallowing in humans involves the coordination of both brainstem and cerebral swallowing control regions. Peripheral sensory inputs are necessary for safe and efficient swallowing, and their importance to the patterned components of swallowing has been demonstrated. However, the role of sensory inputs to the cerebral system during volitional swallowing is less clear. We used four conditions applied during functional magnetic resonance imaging to differentiate between sensory, motor planning, and motor execution components for cerebral control of swallowing. Oral air pulse stimulation was used to examine the effect of sensory input, covert swallowing was used to engage motor planning for swallowing, and overt swallowing was used to activate the volitional swallowing system. Breath-holding was also included to determine whether its effects could account for the activation seen during overt swallowing. Oral air pulse stimulation, covert swallowing and overt swallowing all produced activation in the primary motor cortex, cingulate cortex, putamen and insula. Additional regions of the swallowing cerebral system that were activated by the oral air pulse stimulation condition included the primary and secondary somatosensory cortex and thalamus. Although air pulse stimulation was on the right side only, bilateral cerebral activation occurred. On the other hand, covert swallowing minimally activated sensory regions, but did activate the supplementary motor area and other motor regions. Breath-holding did not account for the activation during overt swallowing. The effectiveness of oral-sensory stimulation for engaging both sensory and motor components of the cerebral swallowing system demonstrates the importance of sensory input in cerebral swallowing control.
Lowell, Soren Y.; Poletto, Christopher J.; Knorr-Chung, Bethany R.; Reynolds, Richard C.; Simonyan, Kristina; Ludlow, Christy L.
|Practitioners and parents are seeking ways to help children who are not able to integrate sensory information; this has generated recent media attention. A child's inability to integrate sensory information can have implications for the whole family and their everyday routines. Research conducted by occupational therapists has provided a rich…
The aim of this study was to develop a sensory profile for cooked gilthead sea bream (Sparus aurata). A total of 21 sessions (8 preliminary, 7 training and 6 for panel performance evaluation) were carried out on cooked samples from both fresh and frozen fish. During preliminary sessions, sample preparation and experimental conditions were established and 13 sensory attributes selected
The objective of this study was to examine the applicability of the short sensory profile (SSP) for screening sensory processing disorders (SPDs) among typical children in Israel, and to evaluate the relationship between SPDs and socio-demographic parameters. Participants were 395 Israeli children, aged 3 years to 10 years 11 months, with typical…
The vasculature of the eye and the heart share several common characteristics. The easily accessible vessels of the eye are therefore—to some extent—a window to the heart. There is interplay between cardiovascular functions and risk factors and the occurrence and progression of many eye diseases. In particular, arteriovenous nipping, narrowing of retinal arteries, and the dilatation of retinal veins are important signs of increased cardiovascular risk. The pressure in the dilated veins is often markedly increased due to a dysregulation of venous outflow from the eye. Besides such morphological criteria, functional alterations might be even more relevant and may play an important role in future diagnostics. Via neurovascular coupling, flickering light dilates capillaries and small arterioles, thus inducing endothelium-dependent, flow-mediated dilation of larger retinal vessels. Risk factors for arteriosclerosis, such as dyslipidaemia, diabetes, or systemic hypertension, are also risk factors for eye diseases such as retinal arterial or retinal vein occlusions, cataracts, age-related macular degeneration, and increases in intraocular pressure (IOP). Functional alterations of blood flow are particularly relevant to the eye. The primary vascular dysregulation syndrome (PVD), which often includes systemic hypotension, is associated with disturbed autoregulation of ocular blood flow (OBF). Fluctuation of IOP on a high level or blood pressure on a low level leads to instable OBF and oxygen supply and therefore to oxidative stress, which is particularly involved in the pathogenesis of glaucomatous neuropathy. Vascular dysregulation also leads to a barrier dysfunction and thereby to small retinal haemorrhages.
Flammer, Josef; Konieczka, Katarzyna; Bruno, Rosa M.; Virdis, Agostino; Flammer, Andreas J.; Taddei, Stefano
The computational simulation of the performance of human eyes is complex because the optical parameters of the eye depend on many factors, including age, gender, race, refractive status (accommodation and near- or far-sightedness). This task is made more difficult by the inadequacy of the population statistical characteristics of these parameters. Previously we simulated ametropic (near- or far-sighted) eyes using three independent variables: the axial length of the eye, the corneal surface curvature, and the intraocular refractive index gradient. The prescription for the correction of an ametropic eye is determined by its second-order coefficients of the wavefront aberrations. These corrections are typically achieved using contact lens, spectacle lens, or laser surgery (LASIK). However, the higher order aberrations, which are not corrected and are likely complicated or enhanced by the lower-order correction, could be important for visual performance in a darkened environment. In this paper, we investigate the higher order wavefront aberrations of synthetic ametropic eyes and compare results with measured data published in the past decade. The behavior of three types of ametropes is discussed.
ing a believable human face is a challenging subject for computer graphics. Of all parts of the face, the eyes are particularly scrutinized because eye gaze is one of the strongest cues to the mental state of another person. When peo-ple are talking, they look to each others'eyes to judge interest and attentiveness, and in turn look into the eyes
Automatic Red Eye Reduction (RER) technique is one of the essential components for imaging device with flash. We present an efficient RER technique that performs red eye detection followed by a verification procedure and an artifact free red eye correction method. The integral projection based method of red eye detection is fast and efficient in handling wide range of variations
Basavaraja S Vandrotti; Muninder Veldandi; Krishna A Govindarao; Mithun Uliyar; Pranav Mishra
Cognitive activities influence the rate and direction of eye movements, but the effect of various levels of eye activity on cognition has not been tested. Jacobson (1938) claimed to have reduced cognitive activity with some eye exercises by decreasing ocular motility. The current study assessed the effects of ocular relaxation eye exercises, adapted from Jacobson, on two subjects with a
Sixty four patients with eye injuries resulting from assault with chemicals were reviewed. In 17 eyes of 16 patients there was total corneal epithelial loss with varying degrees of limbal ischaemia. Nine eyes were effectively blinded and two eyes suffered less severe but permanent impairment of vision.
Based on the widely used Gullstrand-Le Grand eye model, the individual human eye model has been established here, which has individual corneal data, anterior chamber depth and the eyeball depth. Furthermore, the foremost thing is that the wavefront aberration calculated from the individual eye model is equal to the eye's wavefront aberration measured with the Hartmann-shack wavefront sensor. There are
Huanqing Guo; Zhaoqi Wang; Qiuling Zhao; Wei Quan; Yan Wang
Analytical construction of the eye floating was carried out. Buoyancy equations were deduced including the equation for dynamic equilibrium at various eye (head) orientations in space. Design formulae were derived for evaluating buoyancy force on the eye, negative pressure, stability and compensational (heeling) forces of the eye muscles. PMID:2346754
In patients who experience unilateral chronic pain, abnormal sensory perception at the non-painful side has been reported. Contralateral sensory changes in these patients have been given little attention, possibly because they are regarded as clinically irrelevant. Still, bilateral sensory changes in these patients could become clinically relevant if they challenge the correct identification of their sensory dysfunction in terms of hyperalgesia and allodynia. Therefore, we have used the standardized quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain (DFNS) to investigate somatosensory function at the painful side and the corresponding non-painful side in unilateral neuropathic pain patients using gender- and age-matched healthy volunteers as a reference cohort. Sensory abnormalities were observed across all QST parameters at the painful side, but also, to a lesser extent, at the contralateral, non-painful side. Similar relative distributions regarding sensory loss/gain for non-nociceptive and nociceptive stimuli were found for both sides. Once a sensory abnormality for a QST parameter at the affected side was observed, the prevalence of an abnormality for the same parameter at the non-affected side was as high as 57% (for Pressure Pain Threshold). Our results show that bilateral sensory dysfunction in patients with unilateral neuropathic pain is more rule than exception. Therefore, this phenomenon should be taken into account for appropriate diagnostic evaluation in clinical practice. This is particularly true for mechanical stimuli where the 95% Confidence Interval for the prevalence of sensory abnormalities at the non-painful side ranges between 33% and 50%.
Konopka, Karl-Heinz; Harbers, Marten; Houghton, Andrea; Kortekaas, Rudie; van Vliet, Andre; Timmerman, Wia; den Boer, Johan A.; Struys, Michel M.R.F.; van Wijhe, Marten
It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications.
Lima, William C. C.; Vanzella, Daniel A. T. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, CEP 15980-900, Sao Carlos, SP (Brazil)
While there is general agreement that vision and audition decline with aging, observations for the somatosensory senses and taste are less clear. The purpose of this study was to assess age differences in multimodal sensory perception in healthy, community-dwelling participants. Participants (100 females and 78 males aged 20-89 years) judged the magnitudes of sensations associated with graded levels of thermal, tactile, and taste stimuli in separate testing sessions using a cross-modality matching (CMM) procedure. During each testing session, participants also rated words that describe magnitudes of percepts associated with differing-level sensory stimuli. The words provided contextual anchors for the sensory ratings, and the word-rating task served as a control for the CMM. The mean sensory ratings were used as dependent variables in a MANOVA for each sensory domain, with age and sex as between-subject variables. These analyses were repeated with the grand means for the word ratings as a covariate to control for the rating task. The results of this study suggest that there are modest age differences for somatosensory and taste domains. While the magnitudes of these differences are mediated somewhat by age differences in the rating task, differences in warm temperature, tactile, and salty taste persist. PMID:23625154
IMPORTANCE Dry eye disease (DED) is common, but little is known about factors contributing to symptoms of dry eye, given the poor correlation between these symptoms and objective signs at the ocular surface. OBJECTIVE To explore whether pain sensitivity plays a role in patients' experience of DED symptoms. DESIGN, SETTING, AND PARTICIPANTS A population-based cross-sectional study of 1635 female twin volunteers, aged 20 to 83 years, from the TwinsUK adult registry. MAIN OUTCOMES AND MEASURES Dry eye disease was diagnosed if participants had at least 1 of the following: (1) a diagnosis of DED by a clinician, (2) the prescription of artificial tears, and/or (3) symptoms of dry eyes for at least 3 months. A subset of 689 women completed the Ocular Surface Disease Index (OSDI) questionnaire. Quantitative sensory testing using heat stimulus on the forearm was used to assess pain sensitivity (heat pain threshold [HPT]) and pain tolerance (heat pain suprathreshold [HPST]). RESULTS Of the 1622 participants included, 438 (27.0%) were categorized as having DED. Women with DED showed a significantly lower HPT (P?=?.03) and HPST (P?=?.003)-and hence had higher pain sensitivity-than those without DED. A strong significant association between the presence of pain symptoms on the OSDI and the HPT and HPST was found (P?=?.008 for the HPT and P?=?.003 for the HPST). In addition, participants with an HPT below the median had DED pain symptoms almost twice as often as those with an HPT above the median (31.2% vs 20.5%; odds ratio, 1.76; 95% CI, 1.15-2.71; P = .01). CONCLUSIONS AND RELEVANCE High pain sensitivity and low pain tolerance are associated with symptoms of DED, adding to previous associations of the severity of tear insufficiency, cell damage, and psychological factors. Management of DED symptoms is complex, and physicians need to consider the holistic picture, rather than simply treating ocular signs. PMID:23907167
Vehof, Jelle; Kozareva, Diana; Hysi, Pirro G; Harris, Juliette; Nessa, Ayrun; Williams, Frances K; Bennett, David L H; McMahon, Steve B; Fahy, Samantha J; Direk, Kenan; Spector, Tim D; Hammond, Christopher J
OBJECTIVES:: Early tissue injury and recurrent pain in sickle cell disease (SCD) may alter pain and sensory processing. In this study, we evaluate thermal pain and sensory processing for 27 children aged 10.3 to 18.3 years with SCD and 28 African-American control patients. MATERIALS AND METHODS:: Outcome measures included heat and cold detection thresholds, heat and cold pain thresholds, and thermal perceptual sensitization at the volar surface of the dominant forearm and thenar eminence of the nondominant hand. RESULTS:: Children with SCD were less sensitive to heat detection (P=0.006) and cold detection (P=0.015) stimuli at the thenar eminence compared with controls. At the forearm, no difference was found between groups for cold (P=0.58) or heat (P=0.07) detection thresholds. Children with SCD had increased sensitivity to cold pain at the forearm (P=0.03) compared with controls, but not when measured at the thenar eminence (P=0.084). There was no evidence that children with SCD had altered heat pain thresholds compared with controls. There was no difference between groups for perceptual sensitization at the thenar eminence (41% vs. 39%) (?=0.15, P>0.1) or at the forearm (30% vs. 36%) (?=0.23, P>0.5). DISCUSSION:: Three of ten quantitative sensory tests were found to differ between groups. These results suggest that SCD may influence pain and sensory processing in children, but our interpretation is necessarily cautious. Due to the small differences in measures found between groups, further investigation is required to confirm our findings. If confirmed, the development of population-specific reference standards for quantitative sensory testing may emerge as a useful clinical tool for pain physicians in identifying and quantifying pain and sensory processing in children with SCD. PMID:23629596
O'Leary, James D; Crawford, Mark W; Odame, Isaac; Shorten, George D; McGrath, Patricia A
Evidence suggests that sensory loss may occur in a proportion of patients affected by poliomyelitis. We hypothesize that sensory problems may be a lasting sequela in some polio survivors. Sensory pathways in polio survivors were evaluated clinically and electrophysiologically using sensory evoked potentials (SEPs). Patients with sensory deficits or abnormal SEPs were further evaluated by magnetic resonance imaging (MRI). Twenty-two patients were studied. The mean age was 64.7 years (age range: 56-81 years). Clinically, sensory impairments were found in 4 patients. Upper limb SEPs were normal. Lower limb SEPs were abnormal in 10 patients. In 1 patient, clinical and electrographic findings correlated with a patch of atrophy in the spinal cord, as shown by MRI. Sensory derangements may be found in a proportion of aging polio survivors. SEP studies may add sensitivity when evaluating sensory function in this cohort. It remains unclear whether these sensory abnormalities are related to remote poliomyelitis. Further studies are necessary. PMID:18816600
Prokhorenko, Olga A; Vasconcelos, Olavo M; Lupu, Vitalie D; Campbell, William W; Jabbari, Bahman
In caves one repeatedly finds strikingly convergent patterns of evolution in diverse sets of organisms involving 'regressive' traits such as the loss of eyes and pigmentation. Ongoing debate centers around whether these regressive traits arise as the result of neutral evolutionary processes, or rather by natural selection of 'constructive' traits that arise at the expense of eyes and pigmentation. Recent research on cavefish points to the latter, suggesting that the 'constructive' trait vibrational attractive behavior and the reduction of eye size may share a common genetic basis.See research article http://www.biomedcentral.com/1741-7007/10/108. PMID:23347449
Measurements of oxygen saturation and flow in the retina can yield information about the eye health and the onset of eye pathologies such as Diabetic Retinopathy. Recently we have realized an instrument capable of measuring oxygenation in the retina using six different wavelengths and capable of measuring blood flow using speckle-based techniques. The calibration of such instrument is particularly difficult due to the layered structure of the eye and the lack of alternative measurement techniques. For this purpose we have realized an in vitro model of the human eye. The artificial eye is composed of four layers: the retina vessels, the choroids, the retinal pigmented epithelium (RPE), and the sclera. The retina vessels are modeled with 150 ?m tube connected to a micro-pump delivering 34 ?l/min. The micro-tube, the pump, and a blood reservoir were connected in a closed circulatory system; blood oxygenation in the vessel could be modified using an external oxygen reservoir. The optical properties of all other layers were mimicked using titanium dioxide as a scatterer and ink as an absorber. The absorption coefficient ?a and the scattering coefficient µs of these layers were independently measured using an integrating sphere. Absorption and scattering coefficient of all layers were modified before experimental measurements and a Monte Carlo program was finally used to model the experimental results.
Nabili, A.; Bardakci, D.; Helling, K.; Matyas, C.; Muro, S.; Ramella-Roman, J. C.
This discussion reviews drugs that affect the eye, including antihyperglycemic agents; corticosteroids; antirheumatic drugs (quinolines, indomethacin, and allopurinol); psychiatric drugs (phenothiazine, thioridazine, and chlorpromazine); drugs used in cardiology (practolol, amiodarone, and digitalis gylcosides); drugs implicated in optic neuritis and atrophy, drugs with an anticholinergic action; oral contraceptives (OCs); and topical drugs and systemic effects. Refractive changes, either myopic or hypermetropic, can occur as a result of hyperglycemia, and variation in vision is sometimes a presenting symptom in diabetes mellitus. If it causes a change in the refraction, treatment of hyperglycemia almost always produces a temporary hypermetropia. A return to the original refractive state often takes weeks, sometimes months. There is some evidence that patients adequately treated with insulin improve more rapidly than those taking oral medication. Such patients always should be referred for opthalmological evaluation as other factors might be responsible, but it might not be possible to order the appropriate spectacle correction for some time. The most important ocular side effect of the systemic adiministration of corticosteroids is the formation of a posterior subcapsular cataract. Glaucoma also can result from corticosteroids, most often when they are applied topically. Corticosteroids have been implicated in the production of benign intracranial hypertension, which is paradoxical because they also are used in its treatment. The most important side effect of drugs such as chloroquine and hydroxychloroquine is an almost always irreversible maculopathy with resultant loss of central vision. Corneal and retinal changes similar to those caused by the quinolines have been reported with indomethacin, but there is some question about a cause and effect relationship. The National Registry of Drug Induced Ocular Side Effects in the US published 30 case histories of cataract suspected to be induced by allopurinol; numerous additional cases have been reported to the registry since. Phenothiazine, with an estimated 3% incidence of side effects, appears to be safer than other antipsychotic drugs, but the rate of ocular effects increases with the duration of therapy. Thioridazine and chlorpromazine are known to cause lens deposits and pigmentary retinopathy. There is a significantly high prevalence of thrombophlebitis and pseudotumor cerebri among women who use OCs and thrombotic retinal vascular disease, such as retinal vein occulsion, might be linked with them. It also is probable that, because of altered hydration of the cornea, there is a decreased tolerance to contact lenses. PMID:2864912
In 1980 Young and Harper described a family with an unusual form of distal spinal muscular atrophy associated with vocal cord paralysis. We report a family with three similarly affected subjects. Progressive sensorineural hearing loss was an additional feature in our patients. Electrophysiological and histological investigations did not exclude an involvement of sensory neurones. Whether the classification of this dominant
To evaluate the nature and possible sources of variation in sensory–motor behavior, we measured the signal-to-noise ratio for the initiation of smooth-pursuit eye movements as a function of time and computed thresholds that indicate how well the pursuit system discriminates small differences in the direction, speed, or time of onset of target motion. Thresholds improved rapidly as a function of time and came close to their minima during the interval when smooth eye movement is driven only by visual motion inputs. Many features of the data argued that motor output and sensory discrimination are limited by the same noise source. Pursuit thresholds reached magnitudes similar to those for perception: <2?3° of direction, ?11?15% of target speed, and 8 ms of change in the time of onset of target motion. Pursuit and perceptual thresholds had similar dependencies on the duration of the motion stimulus and showed similar effects of target speed. The evolution of information about direction of target motion followed the same time course in pursuit behavior and in a previously reported sample of neuronal responses from extrastriate area MT. Changing the form of the sensory input while keeping the motor response fixed had significant effects on the signal-to-noise ratio in pursuit for direction discrimination, whereas holding the sensory input constant while changing the combination of muscles used for the motor output did not. We conclude that noise in sensory processing of visual motion provides the major source of variation in the initiation of pursuit.
Osborne, Leslie C.; Hohl, Sonja S.; Bialek, William; Lisberger, Stephen G.
Synopsis The natural environment provides a flux of concurrent stimulation to all our senses, and the integration of information from different sensory systems is a fundamental feature of perception and cognition. How information from the different senses is integrated has long been of concern to several scientific disciplines, including psychology, cognitive science, and the neurosciences, each with different questions and methodologies. In recent years, a growing body of evidence drawn from these various disciplines suggests that the development of early sensory organization is much more plastic and experience-dependent than was previously realized. In this article, I briefly explore some of these recent advances in our understanding of the development of sensory integration and organization and discuss implications of these advances for the care and management of the preterm infant.
Chronic cannabis use has been associated with neurocognitive deficits, alterations in brain structure and function, and with psychosis. This study investigated the effects of chronic cannabis use on P50 sensory-gating in regular users, and explored the association between sensory gating, cannabis use history and the development of psychotic-like symptoms. Twenty controls and 21 regular cannabis users completed a P50 paired-click (S1 and S2) paradigm with an inter-pair interval of 9s. The groups were compared on P50 amplitude to S1 and S2, P50 ratio (S2/S1) and P50 difference score (S1-S2). While cannabis users overall did not differ from controls on P50 measures, prolonged duration of regular use was associated with greater impairment in sensory gating as indexed by both P50 ratio and difference scores (including after controlling for tobacco use). Long-term cannabis users were found to have worse sensory gating ratios and difference scores compared to short-term users and controls. P50 metrics did not correlate significantly with any measure of psychotic-like symptoms in cannabis users. These results suggest that prolonged exposure to cannabis results in impaired P50 sensory-gating in long-term cannabis users. While it is possible that these deficits may have pre-dated cannabis use and reflect a vulnerability to cannabis use, their association with increasing years of cannabis use suggests that this is not the case. Impaired P50 sensory-gating ratios have also been reported in patients with schizophrenia and may indicate a similar underlying pathology. PMID:23628289
A new algorithm is developed to implement automatic eye tracking without prior reference model and prior knowledge of size, orientation, shape, color and other data for the human eyes. The algorithm is based on the analysis of the eye features in eye contrast, eye blinking, and other properties. It consists of two stages. In the initialization stage the algorithm locates the approximate head location from two consecutive video frames. The size of three same size blocks is determined. They are used to detect the left and right eyes. Two eyes are symmetric and blink simultaneously at all the time. The algorithm extracts the similarity features of two eyes and dissimilarity of eyes from the region between eyes which is represented by middle block. The measures are implemented by the analysis of correlation and horizontal contrast property. The algorithm is able to detect the eye status of blinking eyes and closed eye for a period of time in a video frame sequence. This algorithm is a dynamic automatic eye tracking system that can adapt the environment change and reinitialize if the tracking is lost. The experiments of this method show satisfactory results in term of accuracy and reasonable time complexity. It shows that the method can be applied to eye tracking regardless of skin color, orientation of head, size of head, background changing, or other constraints. The experiments are conducted in targeting to a moving head by 20 frames/second video sequence.
Intersensory (Visual/auditory) facilitation of reaction times (RTs) was examined using three different response systems: saccadic eye movements, directed manual responses (deflections of a joystick towards the target location) and simple manual responses....
A group design study was carried out using regulated feedback to enhance functional recovery in stroke patients. Patients trained on three computerized tasks aimed at improving guided limb motion in the hemiplegic arm. The therapeutic group was able to make use of the sensory feedback to outperform the control group in each of the three tasks. The therapeutic group also showed an adaptation of the improved performance on the three tasks. Further investigation is required to demonstrate that such sensory feedback training results in a corresponding improvement in activities of daily living skills. PMID:2266334
A multi-sensory teaching kit includes one or more edible items in symbolic shapes, a handbook including a glossary of meanings for the shapes, and a spiritual lesson. In some embodiments, a souvenir such as a jewelry bead is provided, with an optional text explaining the significance of the souvenir. A method of production of a multi-sensory teaching kit is provided, comprising, forming a cookie into a symbolic shape, writing a handbook including a glossary of meanings of the symbolic shapes, printing a lesson on a spiritual principle, optionally providing a souvenir, and optionally enclosing the cookie, handbook, lesson, and optional souvenir in a container.
Sensory inputs control motor behavior with a strength, or gain, that can be modulated according to the movement conditions. In smooth pursuit eye movements, the response to a brief perturbation of target motion is larger during pursuit of a moving target than during fixation of a stationary target. As a step toward identifying the locus and mechanism of gain modulation, we test whether it acts on signals that are in visual or motor coordinates. Monkeys tracked targets that moved at 15°/s in one of eight directions, including left, right, up, down, and the four oblique directions. In eight-ninths of the trials, the target underwent a brief perturbation that consisted of a single cycle of a 10 Hz sine wave of amplitude ±5°/s in one of the same eight directions. Even for oblique directions of baseline target motion, the magnitude of the eye velocity response to the perturbation was largest for a perturbation near the axis of target motion and smallest for a perturbation along the orthogonal axis. Computational modeling reveals that our data are reproduced when the strength of visual-motor transmission is modulated in sensory coordinates, and there is a static motor bias that favors horizontal eye movements. A network model shows how the output from the smooth eye movement region of the frontal eye fields (FEF(SEM)) could implement gain control by shifting the peak of a visual population response along the axes of preferred image speed and direction. PMID:23719810
A new concept of surveillance system called Wide Area Coverage Infrared Surveillance System (WACISS), based on the human vision, was developed and a first laboratory prototype was demonstrated recently. A second prototype, more operational, is named the Infrared Eye is being built and will be tested in cooperation with the NRCC Flight Research Laboratory. The Infrared Eye will use the new pixel-less quantum well infrared photodetector sensors, coupled to light emitting diodes (QWIP/LED), currently being developed at NRCC Institute for Microstructural Science under DREV sponsorship. The multiple advantages of the pixel-less QWIP/LED over conventional sensors will considerably simplify the design of the system. As the WACISS, the IR Eye will integrate two cameras: the first, with a wide field-of- view, will be used for detection while the second camera, with a narrower field with higher resolution for identification, will be mobile within the WFOV and slaved to the operator's line-of-sight by means of an eye-tracking system. The images from both cameras will be fused and shown simultaneously on a standard high resolution CRT display unit, interfaced with the eye-tracking unit. The basic concepts pertaining to the project and the design constraints of this second prototype are presented.
Chevrette, Paul C.; Fortin, Jean; St-Germain, Daniel; Delisle, Jean
Since the launching of Global Initiative, VISION 2020 “the Right to Sight” many innovative, practical and unique comprehensive eye care services provision models have evolved targeting the underserved populations in different parts of the World. At places the rapid assessment of the burden of eye diseases in confined areas or utilizing the key informants for identification of eye diseases in the communities are promoted for better planning and evidence based advocacy for getting / allocation of resources for eye care. Similarly for detection and management of diabetes related blindness, retinopathy of prematurity and avoidable blindness at primary level, the major obstacles are confronted in reaching to them in a cost effective manner and then management of the identified patients accordingly. In this regard, the concept of tele-ophthalmology model sounds to be the best solution. Whereas other models on comprehensive eye care services provision have been emphasizing on surgical output through innovative scales of economy that generate income for the program and ensure its sustainability, while guaranteeing treatment of the poorest of the poor.
Here we report early cross-sensory activations and audiovisual interactions at the visual and auditory cortices using magnetoencephalography (MEG) to obtain accurate timing information. Data from an identical fMRI experiment were employed to support MEG source localization results. Simple auditory and visual stimuli (300-ms noise bursts and checkerboards) were presented to seven healthy humans. MEG source analysis suggested generators in the auditory and visual sensory cortices for both within-modality and cross-sensory activations. fMRI cross-sensory activations were strong in the visual but almost absent in the auditory cortex; this discrepancy wi