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Schwannomas of the trochlear nerve are relatively rare, and most patients present with preoperative diplopia because of trochlear nerve palsy. We describe the case of a 61-year-old male patient with a trochlear nerve schwannoma and no pre- and postoperative diplopia, despite his trochlear nerve being cut during the operation. We aimed to investigate the frequency of postoperative diplopia associated with intraoperative trochlear nerve disturbance by reviewing previous case reports, wherein postoperative diplopia did not occur after the trochlear nerve was cut intraoperatively. We recorded the frequency of diplopia because of intraoperative trochlear nerve disturbance, such as the trochlear nerve being cut, in cases without pre- and postoperative diplopia. We searched the PubMed, Medline, and Google Scholar databases for works published from 1976 to 2020 and followed the preferred reporting items for systematic reviews and meta-analyses guidelines. We reviewed 36 publications and found 92 cases of trochlear nerve schwannoma. Surgical resection was performed for 43 patients, of whom 40 were kept under observation and 9 were treated with radiation therapy. Of the 43 cases, 9 without preoperative diplopia underwent gross total resection. We analyzed ten cases (including ours) without preoperative diplopia to check for postoperative diplopia. In total, four cases, including ours, did not display postoperative diplopia despite the trochlear nerve being cut. This may be attributed to the preoperatively acquired motor and sensory fusion in the patient's vision because of tumor progression. Our findings may benefit neurosurgeons who treat patients with schwannomas and help them predict patients' outcomes.

Purpose. This study aims to analyze sensory fusion recovery using method of LCD glasses with alternating occlusion of visual fields and compare its efficacy with orthoptic treatment using synoptophore. Material and methods. Eighty-six patients with prior esotropia, post-operative absence of bifoveal fusion and residual angle of deviation

To evaluate whether the results of the health-related quality of life (HRQOL) is associated with the various clinical aspects of intermittent exotropia in children. The HRQOL of children and their parents was evaluated prospectively using the Intermittent Exotropia Questionnaire (IXTQ). The deviation angle, stereo function, sensory fusion, and strabismus control were measured. Two hundred and sixty six children with intermittent exotropia (aged 5–17 years) were included in the study. Child HRQOL was significantly correlated with clinical severity; lower IXTQ scores were associated with a larger deviation (p

We describe a new unified model to explain both binocular fusion and depth perception, over a broad range of depths. At each location, the model consists of an array of paired spatial frequency filters, with different relative horizontal shifts (position disparity) and interocular phase disparities of 0, 90, ±180, or −90 degrees. The paired filters with different spatial profiles (non-zero phase disparity) compute interocular misalignment and provide phase-disparity energy (binocular fusion energy) to drive selection of the appropriate filters along the position disparity space until the misalignment is eliminated; sensory fusion is achieved locally. The paired filters with identical spatial profiles (0 phase disparity) compute the position-disparity energy. After sensory fusion, the combination of position and possible residual phase disparity energies is calculated for binocular depth perception. Binocular fusion occurs at multiple scales following a coarse-to-fine process. At a given location, the apparent depth is the weighted sum of fusion shifts combined with residual phase disparity in all spatial-frequency channels, and the weights depend on stimulus spatial frequency and stimulus contrast. To test the theory, we measured disparity minimum and maximum thresholds (Dmin and Dmax) at three spatial frequencies and with different intraocular contrast levels. The stimuli were Random-Gabor-Patch (RGP) stereograms consisting of Gabor patches with random positions and phases, but with a fixed spatial frequency. The two eyes viewed identical arrays of patches except that one eye’s array could be shifted horizontally and could differ in contrast. Our experiments and modeling reveal two contrast normalization mechanisms: (1) Energy Normalization (EN): Binocular energy is normalized with monocular energy after the site of binocular combination. This predicts constant Dmin thresholds when varying stimulus contrast in the two eyes; (2) DSKL model Interocular interactions: Monocular contrasts are normalized before the binocular combination site through interocular contrast gain-control and gain-enhancement mechanisms. This predicts contrast dependent Dmax thresholds. We tested a range of models and found that a model consisting of a second-order pathway with DSKL interocular interactions and a first-order pathway with EN at each spatial-frequency band can account for both the Dmin and Dmax data very well. Simulations show that the model makes reasonable predictions of suprathreshold depth perception.

AimsBagolini striated lenses are a useful test of binocular vision, but the variations in the striations (frequency and thickness) can impact on the perceived image. Also, responses can be difficult to interpret in young children. Therefore, the aims of this project were to evaluate the impact of striation frequency and the addition of coloured filters on subjective responses.MethodsThree sets of striated lenses were made (small, medium and large striations), each produced in two forms (both lenses clear, or with a red and blue lens). Also, Bagolini glasses (Optiker Ryser) were used, with and without the addition of red and blue filters. Subjects were asked to report what they perceived, with subsequent questions regarding the number and length of lines.ResultsForty-two adult subjects were tested, with uniocular VA ranging from -0.18 to 1.10 logMAR (mean 0.08 ± 0.25). The number of lines seen when varying the line thickness did not vary between coloured and clear lenses (post-hoc analysis following ANOVA, p > 0.1 in all comparisons). Adding red/blue filters to the original Bagolini glasses did not alter the rates of subjects perceiving a cross (Chi-square, p = 0.8). However, the laser-cut lenses produced a significantly shorter light streak than the original lenses (One-way ANOVA, p < 0.001), but the colour of the filters made no difference to the length of streak perceived (Tukey's Test, p = 0.20).ConclusionsThe addition of coloured filters did not impact on the responses given to the original or laser-cut lenses, suggesting this modification may aid responses in children. However, further evaluation is required with finer striations and thinner lenses to improve the visibility of the lines.

Objective: No method exists to measure aniseikonia tolerance in stereoacuity. The brain can compensate for 2%–3% aniseikonia (i.e. 2–3 dioptres of anisometropia) without impairing stereoacuity; however, a substantial proportion of anisometropic patients experience problems caused by disruptions of sensory fusion due to surgically induced aniseikonia. We hypothesized that individual differences in tolerance to aniseikonia exist and sought to develop a method to measure aniseikonia tolerance. Methods: A total of 21 eye-healthy phakic individuals older than 50 years of age and 11 patients awaiting clear lens extraction were included. Patients were tested with best corrected near and distance visual acuity, cover/uncover test, eye dominance test, stereoacuity threshold (TNO test), slit lamp examination and ocular coherence tomography. The stereoacuity threshold was determined with aniseikonia induced by different size lenses ranging from 1% to 9% magnification of both eyes in increments of 1%. The aniseikonia tolerance range (ATR) was defined as the percentage aniseikonia in which the stereoacuity threshold was maintained. Results: We examined 32 patients with a median age of 65 (95% CI: 62–66 years), CDVA better than 6/7.5 (0.1 logMAR), and median near visual acuity better than 6/6 (0.0 logMAR). The median stereoacuity threshold was 60 arcsec (maximum 30, minimum 120). We observed large inter-individual differences in ATR: 6/31 (19%) participants had an ATR of ≤1%, 1/31 (3%) had an ATR of 1-5%, 7/31 (22%) had an ATR of 5-10%, and 17/31 (54%) had an ATR of >10%. Conclusion: We present a reliable method for measuring the amount of aniseikonia that a person can tolerate without impairing stereopsis. We report large inter-individual differences in tolerance of aniseikonia.

Restoring locomotion functionality of transfemoral amputees is essential for early rehabilitation treatment and for preserving mobility and independence in daily life. Research in wearable robotics fostered the development of innovative active mechatronic lower-limb prostheses designed with the goal to reduce the cognitive and physical effort of lower-limb amputees in rehabilitation and daily life activities. To ensure benefits to the users, active mechatronic prostheses are expected to be aware of the user intention and properly interact in a closed human-in-the-loop paradigm. In the state of the art various cognitive interfaces have been proposed to online decode the user's intention. Electromyography in combination with mechanical sensing such as inertial or pressure sensors is a widely adopted solution for driving active mechatronic prostheses. In this framework, researchers also explored targeted muscles re-innervation for an objective-oriented surgical amputation promoting wider usability of active prostheses. However, information kept by the neural component of the cognitive interface deteriorates in a prolonged use scenario due to electrodes-related issues, thereby undermining the correct functionality of the active prosthesis. The objective of this work is to present a novel controller for an active transfemoral prosthesis based on whole body awareness relying on a wireless distributed non-invasive sensory apparatus acting as cognitive interface. A finite-state machine controller based on signals monitored from the wearable interface performs subject-independent intention detection of functional tasks such as ground level walking, stair ascent, and sit-to-stand maneuvres and their main sub-phases. Experimental activities carried out with four transfemoral amputees (among them one dysvascular) demonstrated high reliability of the controller capable of providing 100% accuracy rate in treadmill walking even for weak subjects and low walking speeds. The minimum success rate was of 94.8% in performing sit-to-stand tasks. All the participants showed high confidence in using the transfemoral active prosthesis even without training period thanks to intuitiveness of the whole body awareness controller.

This work proposes a new methodology for the detection of discontinuities in the weld bead applied in Shielded Metal Arc Welding (SMAW) processes. The detection system is based on two sensors-a microphone and piezoelectric-that acquire acoustic emissions generated during the welding. The feature vectors extracted from the sensor dataset are used to construct classifier models. The approaches based on Artificial Neural Network (ANN) and Support Vector Machine (SVM) classifiers are able to identify with a high accuracy the three proposed weld bead classes: desirable weld bead, shrinkage cavity and burn through discontinuities. Experimental results illustrate the system's high accuracy, greater than 90% for each class. A novel Hierarchical Support Vector Machine (HSVM) structure is proposed to make feasible the use of this system in industrial environments. This approach presented 96.6% overall accuracy. Given the simplicity of the equipment involved, this system can be applied in the metal transformation industries.

Several diagnostic symptoms of the visual-processing deficit Meares-Irlen/Visual Stress Syndrome are remarkably similar to symptom manifestations reported by individuals with chronic fatigue syndrome (CFS). We surveyed the specific incidences of nine widely-recognised symptoms of visual stress (VS) in a group of subjects (n=20) previously diagnosed with CFS. The presence of each symptom of VS in the CFS group was compared to its respective presence in both an age and sex matched healthy comparison group (n=46), and an age and sex matched group comprised of individuals (n=14) diagnosed with VS. Results showed the frequencies of all nine VS symptoms in the CFS-diagnosed group to be significantly higher (p=.032 – p

PURPOSE: To evaluate fine motor ability in children treated for unilateral congenital or infantile cataract. METHODS: Twenty-three children 3–13 yearsof agewho were treated for unilateral congenital or infantile cataract and 38 age-similar control children were enrolled. Children completed five fine motor skills tasks (unimanual dexterity, bimanual dexterity, drawing trail, aiming, catching) from the Movement Assessment Battery for Children-2. Raw scores were converted into standardized scores, with higher scores indicating better performance. RESULTS: Compared with controls, children treated for unilateral cataract scored lower on drawing trail (P = 0.009), aiming (P = 0.009), and catching (P < 0.001) but not on unimanual (P = 0.77) or bimanual dexterity (P = 0.31). Poorer affected eye visual acuity was moderately related to poorer performance for unimanual dexterity (r = −0.47; P = 0.025), bimanual dexterity (r = −0.50; P = 0.014), and catching (r = −0.41; P = 0.051). Those with a poor visual outcome (>0.6 logMAR) had worse performance than those with a good visual outcome (≤0.6 logMAR) for all tasks (all P values, 0.008–0.09) except aiming. Cataract type (congenital, 9; infantile, 14) and sensory fusion by Worth 4-Dot testing at 33 cm (pass, 10; fail, 13) had no effect on fine motor performance (all P values, 0.12–0.98). CONCLUSIONS: In our study cohort, fine motor deficits were found in children treated for congenital or infantile unilateral cataract.

The most common functional benefits from strabismus surgery in the adult patient are restoration of binocular vision and elimination of diplopia and/or a compensatory head posture. Adult patients with chronic strabismus have been thought to have the potential to achieve only a cosmetic result from surgery. On the contrary, several studies have shown that unexpected sensory fusion is possible after excellent postoperative motor alignment in these patients. Other functional benefits of strabismus surgery in the adult patient include the expansion of binocular visual fields in patients with esotropia and the psychosocial and economic benefits from restoration of ocular alignment. This paper will explore the impact of untreated strabismus in the adult patient and what changes occur in the patient's quality of life once strabismus has been successfully treated.

Saccadic reaction times can be shortened by an additional sensory modality (e.g. auditory, tactile) presented in temporal proximity to the triggering cue. Whereas somatosensory cues given by sudden perturbations of the support surface can trigger appropriate postural adjustments to maintain upright stance, it is not known how gaze executions are affected by the dual task of maintaining upright balance while redirecting gaze. It was hypothesized that the onset latency of gaze movements toward visual targets will be shortened by sudden surface perturbations following visual target shifts to prompt a stable visual anchor for postural stabilization. Eight subjects stood on a movable platform with gaze fixated on a central target 2 m directly in front, and were instructed to shift their gaze to lateral targets located along a 63 degrees arc to the right and left. The trials began with the central target lit followed randomly by either the right, left or center target. Fifty or 250 ms following this target shift, balance was perturbed by a sudden yaw movement of the support surface (15.5 degrees over 210 ms at 130 degrees /s), with no stepping or large arm reactions observed. The latency of the gaze shifts was significantly shortened (by approximately 72 ms) when executed simultaneously with a surface perturbation. A decrease in excitation latency was also observed in the cervical paraspinals and sternocleidomastoid muscles. Postural responses in the ankle and knee muscles were not affected by gaze shifts. Pelvic horizontal angular motion closely followed surface motion whereas head motion was influenced by gaze shifts. During the combined gaze shift and surface motion conditions, thorax movement excursion was larger and not correlated with either the surface motion or visual target shift. In conclusion, postural adjustments in response to sudden surface yaws facilitate voluntary gaze shift execution and this enhancement may result from the sensory fusion of somatosensory and visual information.

Background: There is controversy regarding whether or not visually mature individuals can permanently lose stereoacuity and under what conditions stereoacuity can be regained. Some have proposed a critical duration of misalignment in adults beyond which recovery of fine stereoacuity is not possible, despite successful surgical alignment. Methods: Twenty-one adult patients (median age 59 years) with large-angle acquired strabismus and who were successfully surgically aligned after 7 to 501 months of misalignment were studied. Subjects had no evidence of motor or sensory fusion since the onset of strabismus, on preoperative exam, or by history. Stereoacuity was measured using 1 or more of the Frisby, Preschool Randot and Titmus tests, at 8 weeks and at 12 months. Data from tests with monocular clues were not used. Results: At total of 67% of patients with chronic acquired strabismus and no preoperative fusion regained measurable stereoacuity and 44% regained fine stereoacuity of at least 60 seconds of arc. Of 10 patients with no or subnormal stereoacuity 8 weeks postoperatively, 6 (60%) showed improvement at the 12-month visit. Misalignment for up to 4 years did not preclude the development of postoperative stereoacuity. Conclusions: Although a minority of adult strabismus patients may permanently lose stereoacuity despite successful alignment for acquired strabismus, the majority do show recovery. Such recovery of stereoacuity may take several months to occur. In our adult series, duration of misalignment did not predict failure to recover stereoacuity. (J AAPOS 2002;6:233-7)

Surface electrical potential and observational growth recordings were made of a protoplasmic tube of the slime mould Physarum polycephalum in response to a multitude of stimuli with regards to sensory fusion or multisensory integration. Each stimulus was tested alone and in combination in order to evaluate for the first time the effect that multiple stimuli have on the frequency of streaming oscillation. White light caused a decrease in frequency whilst increasing the temperature and applying a food source in the form of oat flakes both increased the frequency. Simultaneously stimulating P. polycephalum with light and oat flake produced no net change in frequency, while combined light and heat stimuli showed an increase in frequency smaller than that observed for heat alone. When the two positive stimuli, oat flakes and heat, were combined, there was a net increase in frequency similar to the cumulative increases caused by the individual stimuli. Boolean logic gates were derived from the measured frequency change., 18 pages, 2 figures, 4 tables

In this paper, we propose a near infrared images upsampling method using RGB camera information. In general, the resolution of near infrared images is lower than that of RGB images by factor of 4. Simulation results show the visual performance. It is obvious that the details of result image are clearer than that of low-resolution image.

In this paper, design of an autonomous microrobotic endoscopy system is presented. The proposed microrobotic endoscope is a vision-guided device, developed to facilitate navigation inside a human colon. The design of the entire system is divided into three areas viz. design of a microrobotic carrier, path planning and guidance, and an off-board control system. A microrobotic design based on pneumatic mechanisms to achieve locomotion and steering is explained. General mathematical analysis governing the differential steering of the robotic tip is also described. The path planning of the microrobot is carried out based on the sensory fusion utilising the quantitative parameters from the captured images and the tactile sensors. A real-time image segmentation scheme is described for extracting the lumen from endoscopic images. An off-board control system to control the directional movements of the microrobot is also explained. The proposed endoscopy system was tested with physical models and animal colons and the experimental observations are presented.

In general, it is difficult to present haptic information because arbitrary curvatures of the curved surface and many degrees of freedom need to be realized. On the other hand, psychophysical studies have suggested that human visual and tactile sensations have an illusory fusion characteristic. This means that we can recognize curved surfaces of objects through visual and tactile sensations, even if exact tactile information is not presented. Hence, by utilizing the human characteristic of sensory fusion, realization of a haptic device of curved surface can be simplified. From such motivation, the human fusion characteristics of visual and tactile sensation are measured, and are quantitatively analyzed. Based on the analyzed results, a haptic device of two-dimensional curved surface for three fingers is developed. In the haptic device, only four curved patterns are utilized instead of presenting many curved patterns. Performance of the developed haptic device is proved through evaluated experiments.

In this paper presents a novel design of a microrobotic colonoscopy (MRC) system. The proposed microrobotic colonoscope is an autonomous vision-guided device, which is designed to navigate inside a human colon for the purpose of observation, analysis and diagnosis. It is developed to alleviate the shortcomings in the existing manual colonoscopy procedure, which is generally cumbersome and tedious for the colonoscopist and painful to the patients. The MRC system is divided into three areas, i.e. design of the microrobotic device, path planning and guidance, and offboard control system. A novel design of the microrobot is presented which utilizes a pneumatic mechanism to achieve locomotion and steering. A new concept of clamping the colon wall based on passive vacuum devices is suggested. General mathematical analysis governing the differential steering of the robotic tip is also described. The path planning of the microrobot is carried out based on the sensory fusion utilizing the quantitative parameters d...

In general, it is difficult to present tactile information because arbitrary curvatures of the curved surface and many degrees of freedom need to be realised. On the other hand, psychophysical studies have suggested that human visual and tactile sensations have an illusory fusion characteristic. This means that we can recognise curved surfaces of objects through visual and tactile sensations, even if exact tactile information is not presented. Hence, by utilising the human characteristic of sensory fusion, realisation of a curved surface display can be simplified. From such motivation, the human fusion characteristics of visual and tactile sensation are measured, and are quantitatively analysed. Based on the analysed results, a curved surface display for three fingers is developed. In the curved surface display, only four curved patterns are utilised instead of presenting many curved patterns. Performance of the developed tactile display is proved through evaluated experiments.

Deep Belief Networks (DBNs) have recently shown impressive performance on a broad range of classification problems. Their generative properties allow better understanding of the performance, and provide a simpler solution for sensor fusion tasks. However, because of their inherent need for feedback and parallel update of large numbers of units, DBNs are expensive to implement on serial computers. This paper proposes a method based on the Siegert approximation for Integrate-and-Fire neurons to map an offline-trained DBN onto an efficient event-driven spiking neural network suitable for hardware implementation. The method is demonstrated in simulation and by a real-time implementation of a 3-layer network with 2694 neurons used for visual classification of MNIST handwritten digits with input from a 128 × 128 Dynamic Vision Sensor (DVS) silicon retina, and sensory-fusion using additional input from a 64-channel AER-EAR silicon cochlea. The system is implemented through the open-source software in the jAER project and runs in real-time on a laptop computer. It is demonstrated that the system can recognize digits in the presence of distractions, noise, scaling, translation and rotation, and that the degradation of recognition performance by using an event-based approach is less than 1%. Recognition is achieved in an average of 5.8 ms after the onset of the presentation of a digit. By cue integration from both silicon retina and cochlea outputs we show that the system can be biased to select the correct digit from otherwise ambiguous input., Frontiers in Neuroscience, 7, ISSN:1662-453X, ISSN:1662-4548

O'Shea and Crassini (1982, Perception & Psychophysics32 195–196) demonstrated that fusion persists for vertical lines with an orientation disparity of 8°, but diplopia is experienced in simultaneously presented horizontal lines with the same disparity. They concluded that the neural fusion process fuses larger horizontal disparities than vertical disparities. Kertesz criticised their demonstration because it did not quantify the possible motor component associated with fusing their counter-rotated images. Krekling and Blika argued that the demonstrated anisotropy is due to a disparity bias in the visual system, owing to the temporalward tilt of corresponding vertical meridians. We addressed these criticisms with a novel stimulus and presentation protocol, that rendered compensatory cyclovergence eye movements unlikely and explored a wide range of orientation disparities. We confirmed O'Shea and Crassini's vertical/horizontal anisotropy in orientation fusion limits. In addition, our measurements of vertical lines showed that the distributions of fused responses as a function of orientation disparity in the upper and lower visual fields were shifted relative to each other. Therefore, the distributions of fusible orientation disparities are wider for vertical lines than horizontal lines and are relatively shifted as predicted if the fusional range is centred around the vertical horopter.

Indoor localization and monitoring system of robots and people are essential issues in robotics research. Several monitoring systems are currently under development by different investigators but they do encounter significant difficulties. For instance, a Pyroelectric Infrared (PIR) system provides less accurate information of human location and is restricted when there are multiple targets. Furthermore, a Radio Frequency (RF) localization system is constrained by its limited accuracy.

Study of the vision process biomechanics is an important part of the vision care. We acquire more than 90% of information by vision system, thus the system is the most important for our quality of life. Physicians focus their attention on care about the eyesight especially on infants. In this period the vision system develops and any disturbance can affect the development process and cause a pathological progress. The focus of our research is in measuring biomechanics of the vision process, sensory fusion and image observation features especially in infants with strabismus to support the diagnose and treatment. But in this text we will talk about methods and present results in normal (health) children.

Anisometropia is reported to increase with age; however, the relationship between the development of anisometropia and binocular vision has not been determined. The purpose of this study was to determine the relationship between anisometropia and binocular vision after esotropia (ET) surgery. The medical records of 51 consecutive patients with ET who had undergone ET surgery were studied. Patients with amblyopia or anisometropia ≥2 diopters (D) before surgery were excluded. The average age of the patients at the time of surgery was 4.5 ± 3.7 years, and the average postoperative period was 5.0 ± 2.2 years. The refractive errors (spherical equivalent) in both eyes were measured preoperatively and postoperatively. Binocular visual function was evaluated with a modified Worth-4 dot test. At the final visit, average anisometropia was 0.98 ± 1.30 D, which was significantly greater than the preoperative value of 0.36 ± 0.46 D (P < 0.001). Anisometropia ≥2 D was observed in ten patients (23%) postoperatively. One patient was able to fuse a target of ≥2° (10%) in the anisometropia ≥2 D group, significantly fewer than the 13 patients (32%) in the anisometropia

In this work authors describe a high-efficiency architecture for parallel sensory fusion and real-time management of heterogeneous multi-transducers data processing. The interfaces with the external sensors and actuators, the specific control and processing methods and the data flowing through inner communication channels can be defined. For such entities the framework offers extendable structures, whose base implementation allows the realisation of high-efficiency data processing.Systems equipped with multiple transducers, tasks execution that are running as cooperative processes, off-line and real-time data aquisition and analysis tools, general stand alone applications represent some of the potential application areas. A library-oriented interface was preferred to a user-oriented interface. Real-time analysis and actuation is gained for all the transducers and for all the running processes. Multiprocess cooperation is possible thanks to a homogeneous communication language. The user can create extensions of new models of entities and processes. The data acquisition from sensor devices is granted by a protocol interface that is able to dispatch data coming from input systems. The data processing may be specified by the user inside the framework core. The actuator driving is granted by a protocol interface that is able to dispatch data from the framework core. Filters for sensory and actuating systems can be redefined according to the particular device technology; the efficiency of the filtering and buffering processes over the data coming from sensors and over the data directed to actuating devices is delegated to appropriate interfaces. The portability is allowed by a layered structure, an abstraction, and by the specification of the I/O drivers. A modular, reusable and object

• The sensorimotor examination clarifies the patient’s symptoms and expectations, precisely quantifies the ocular deviation, and determines the potential for binocular single vision in a focused, efficient manner.

We present here a bilateral model for the horizontal rotational vestibulo-ocular reflex (VOR) that integrates sigmoidal nonlinearities in the response of VOR interneurons. This model realistically links the systems level approach to the underlying neural mechanisms. It is capable of producing VOR modulations with viewing context using only the efference copies of eye position signals to make novel predictions.

This paper presents the research segment of development of methodology for determining odor level of various applications using two different concepts; Fuzzy logic based algorithm and Artificial Neural Network (ANN) based algorithm. Three different gas sensors are used which respond to ammonia (NH3), hydrogen sulfide (H2S) and methane (CH4). Sensory fusion is achieved through processing the analog to digital converted values of sensor outputs using the algorithm to determine the odor level of various types of predetermined odors. Olfactometry was used to determine the desired outputs (odor levels) of the algorithms. Fuzzy logic algorithm uses Zadeh-Mamdani type Fuzzy inference system and the neural network approach uses feedforward backpropogation algorithm. Further this paper presents some results based on gathered data from various odor-emitting sources.

In normal vision, both eyes are precisely aligned on an object of regard, so the images from that object fall on the fovea of each eye. Precise image orientation on corresponding retinal areas of each eye permits cortical processing, which results in the merging or fusion of the two images. This process is termed binocular fusion. There are two important aspects of binocular fusion: sensory fusion and motor fusion. This chapter discusses the process of binocular vision and provides an introduction to strabismus.

International audience; For any sighted mobile creature, whether it be natural or artificial, stabilizing the visual system is a much more crucial issue than that of preventing a snapshot from being blurred by the unsteadiness of a human photographer. The more immune the eye of an animal or a robot is to various kind of disturbances such as body or head movements of all kinds, the less troublesome it will be for the visual system to carry out its many information processing tasks when walking or flying in unknown environments. The gaze control system that we describe in this paper takes a lesson from the Vestibulo Ocular Reflex (VOR) that is known to contribute to the stabilization of the human eyes. The originality and performances of the control system arise from the merging of two sensory modalities: a retinal position signal is yielded by a novel piezo-based visual sensor called OSCAR (Optical Sensor for the Control of Autonomous Robots) a VOR reflex is merged with a visual smooth pursuit reflex. Our gaze controller involves a feedforward eye control based on measurements of the angular head speed by a rate gyro. The performances of the gaze controller were tested on-board a miniature (5 grams) oculomotor system, which makes use of the OSCAR visual sensor. The combined visual/inertial sensory-motor controller enables the gaze to be stabilized within a 12-times smaller range than the perturbing head movements, which were applied here at frequencies of up to 3 Hz with an amplitude of 6° peak-topeak. This is a relatively high standard of performance in terms of rejecting head movement disturbances; in any case, these performances are comparable to those which the human visual system is capable of.

In general, it is difficult to present tactile information due to arbitrary curvatures of the curved surface and many degrees of freedom needed to be realized. On the other hand, psychophysical studies suggested that human visual and tactile sensations have an illusory fusion characteristic. It means that we can recognize curved surfaces of objects through visual and tactile sensations, even if exact tactile information is not presented. Hence, by utilizing the human characteristic of sensory fusion, realization of a tactile display can be simplified. From such motivation, the human fusion characteristics of visual and tactile sensation are measured, and are quantitatively analyzed. Based on the analyzed results, a tactile display is developed. In the tactile display, only four curved patterns are utilized instead of presenting many curved patterns. Performance of the developed tactile display is proved through evaluated experiments.

The size of sensory fusional and refusional areas of seven observers were measured for three fixation distances and eight retinal eccentricities. Results show that sensory fusion is affected by fixation distance and retinal eccentricity.

To analyze the effectiveness of the checkerboard pattern stimulator (CPS) in facilitating stereopsis in patients with acquired esotropia. Fourteen patients were treated with checkerboard pattern stimulation following surgical correction of the ocular alignment. In order to determine the cause of the difference in the effectiveness of CPS on exotropes and esotropes, a separate study was carried out on 15 subjects: 5 orthophores, 5 exophores, and 5 esophores. Eight of the 14 patients achieved stereopsis; the remaining 6 cases did not show marked improvement in stereoacuity. The CPS was more effective on exotropes, as reported previously, than on esotropes (P = 0.047, χ2 test). By recording the ocular positions of the 15 subjects in the separate study, we found a tendency toward exodeviation in the orthophoric and exophoric subjects but not in esophoric subjects. Our results suggest that CPS develops sensory fusion by providing an identical pattern simultaneously to the foveas of both eyes and has no effect on convergence training and motor fusion.

Aim: To determine whether the level of sensory fusion in normal participants is affected significantly by fixation light intensity. Methods: Seventeen normal adult participants had sensory fusion measurements taken using the Sbisa bar, combined with Bagolini glasses, as a control for binocular single vision, whilst fixating lights of three different intensities: 150 lux, 250 lux and 350 lux. Data were analysed using Friedman’s test and the Wilcoxon matched pairs signed ranks test. Results: Seventeen participants were tested (mean 35.3 years, range 23–60 years). Friedman’s test showed at least two of the light intensities had a statistically significant effect upon sensory fusion results ( p = 0.011). Wilcoxon matched pairs signed rank testing found no statistically significant difference in levels of sensory fusion when fixating the 150 lux and 250 lux fixation lights ( p = 0.194). There was a statistically significant difference in the level of sensory fusion when fixating the 150 lux and 350 lux lights ( p = 0.011) and the 250 lux and 350 lux lights ( p = 0.017). Conclusion: Changing the intensity of the fixation light from 150 lux to 350 lux and from 250 lux to 350 lux significantly affected the level of sensory fusion measured. The higher the intensity of the light, the greater the filter needed to break fusion. The clinical significance of these results is considered.

The nature of sensory interactions during human fusional response was investigated using band-limited, 10th-derivative-of-Gaussian patterns. Experiments were performed to investigate the effects of spatial separation, disparity magnitude, and stimulus spatial frequency on horizontal sensory fusional amplitudes (SFA). When the disparities in the inducing and probe regions were in the same direction the SFA for the probe increased; when the disparities were in opposite directions the SFA was reduced. Increases and decreases in the SFA for the probe caused by the inducing stimulus were designated enhancement and inhibition respectively. Both enhancement and inhibition increased with increasing inducing disparity. They were evident over a range of spatial frequencies from 0.75 to 3.0 c/deg and among retinal regions separated by as much as 1.5 deg arc. The SFA for the probe was not inhibited when the peak spatial frequency of the inducing stimulus was 2 octaves higher than that of the probe. The observed changes in SFA were found to be due to shifts in location rather than changes in the extent of the fusional range for the probe.

Besides loss of convergence and accommodation, head injuries can cause fusion deficiency. Part function of sensory fusion is tolerance to sphaerical and meridional aniseikonia. We will present a patient, whose aniseikonia tolerance decreased after a brain concussion.

Simultaneous objective (based on binocular eye movement recording) and subjective (nonius line displacement) measurements of horizontal and vertical fusional response were carried out in order to examine the nature of sensory fusional compensation. It was found that the presence of sensory compensation in one retinal region affects the sensory representations of neighboring regions. Unlike motor compensation, however, sensory compensation affects fusible and nonfusible contours differently. The implication of these results is examined for the reliability of subjective determinants of binocular status.

Prism Adaptation is a successful means by which to facilitate the effective planning of strabismus surgery. When applied in certain types of ocular misalignment, it is thought to significantly impr...

Detection and diplopia thresholds for vertical disparities are found to decrease when the presentation time of the stimulus with disparity is increased between 20 msec and 2 sec. This result supports the following notions previously put forward in literature: (a) the human visual system embodies detection processes which reveal vertical disparities; there is no sensory fusion mechanism in this system that gradually conceals vertical disparities: (b) the detection of vertical disparity in tachistoscopically presented stimuli is not based upon the initial appearance of the stimulus with disparity.

Horizontal binocular disparity is the fundamental stimulus for both fusional vergence and stereopsis, but whether common disparity-sensitive mechanisms are involved in both responses is unknown. To determine whether the sensitivities of motor and sensory fusion are interdependent, we studied vergence eye movements and depth discrimination, using stimuli with haplopic binocular disparities, in subjects with normal stereopsis and in subjects with mild to severe stereoanomalies. Our results showed that the subjects' disparity discrimination functions varied from nearly perfect discrimination to chance performance for all of the experimental stimuli. Their sensory functions did not necessarily predict the shape of their motor fusion functions, but in most cases were correlated with the subject's fixation disparities. The results support the conclusion that the stereoanomalies and vergence anomalies that previously have been described for coarse binocular disparities also extend to the small, haplopic binocular disparities. The independence of the response properties of sensory and motor fusion suggests that neural pathways for sensory and motor fusion separate after the initial disparity-selective mechanisms in primary visual cortex.

Fusional cyclovergence was demonstrated for the first time, using ab objective photographic method. It was discovered that the results of subjective and objective measurements of cyclovergence agreed exactly. The largest fusional cyclovergence observed was 8 degrees. The cyclovergence partly cancels out the cyclodisparity presented. The greater part of the cyclodisparity usually remains. The maximum aplitude of the sensory cyclofusion is of the order of 8 degrees. The cyclovergence response is greatest when large fusion images with numerous horizontal contours are presented. The motor mechanism of cyclofusion presupposes the existence of recently demonstrated cyclodisparity detectors. The amplitude of sensory fusion is determined by the vertical diameter of the peripheral Panum areas.

The objective misalignment of haploscopic vernier lines induced by some oculomotor imbalance (e.g. prism strain, heterophoria) is called fixation disparity (Fig. 1; Ogle et al. 1967). As a matter of fact fixation disparity is to correspond to some mismatch of the fusion pattern in the test person’s subjective space. How can this mismatch be processed in the test person’s visual system? Can this be done by straightforward sensory fusion or is it achieved by partial suppression of bifoveal vision? The interactions between fixation disparity and foveal suppression have been discussed in the literature (Ogle et al. 1967) but — to our best knowledge — nobody really tried to show them.