Theses and Dissertations

Permanent URI for this collection

https://hdl.handle.net/10315/42925

This collection consists of theses and dissertations produced by graduate students affiliated with the York Centre for Vision Research. These works represent significant contributions to the interdisciplinary field of vision science and have been approved in accordance with the academic standards of their respective graduate programs (including Biology, Digital Media, Electrical Engineering and Computer Science, Interdisciplinary Studies, Kinesiology & Health Science, Philosophy, Physics & Astronomy, Psychology, and others). This collection is managed and deposits authorized by the Coordinator for the Centre.

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Open Access
A 360-degree Omnidirectional Photometer Using a Ricoh Theta Z1
(2023-12-08) MacPherson, Ian Michael; Brown, Michael S.
Spot photometers measure the luminance emitted or reflected from a small surface area in a physical environment. Because the measurement is limited to a "spot," capturing dense luminance readings for an entire environment is impractical. This thesis demonstrates the potential of using an off-the-shelf commercial camera to operate as a 360-degree luminance meter. The method uses the Ricoh Theta Z1 camera, which provides a full 360-degree omnidirectional field of view and an API to access the camera's minimally processed RAW images. Working from the RAW images, this thesis describes a calibration method to map the RAW images under different exposures and ISO settings to luminance values. By combining the calibrated sensor with multi-exposure high-dynamic-range imaging, a cost-effective mechanism for capturing dense luminance maps of environments is provided. The results show that the Ricoh Theta calibrated as a luminance meter performs well when validated against a significantly more expensive spot photometer.
Open Access
A Solution for Scale Ambiguity in Generative Novel View Synthesis
(2025-04-10) Forghani, Fereshteh; Brubaker, Marcus
Generative Novel View Synthesis (GNVS) involves generating plausible unseen views of a scene given an initial view and the relative camera motion between the input and target views using generative models. A key limitation of current generative methods lies in their susceptibility to scale ambiguity, an inherent challenge in multi-view datasets caused by the use of monocular techniques to estimate camera positions from uncalibrated video frames. In this work, we present a novel approach to tackle this scale ambiguity in multi-view GNVS by optimizing the scales as parameters in an end-to-end fashion. We also introduce Sample Flow Consistency (SFC), a novel metric designed to assess scale consistency across samples with the same camera motion. Through various experiments, we demonstrate our approach yields improvements in terms of SFC, providing more consistent and reliable novel view synthesis.
Open Access
Abnormal Brain Connectivity in the Primary Visual Pathway in Human Albinism
(2016-09-20) Grigorian, Anahit; Schneider, Keith A.
In albinism, the ipsilateral projection of retinal axons is significantly reduced, and most fibres project contralaterally. The retina and optic chiasm have been proposed as sites for misrouting. The number of lateral geniculate nucleus (LGN) relay neurons has been linked to LGN volume, suggesting a correlation between LGN size and the number of tracts traveling through the optic radiation (OR) to the primary visual cortex (V1). Using diffusion data and both deterministic and probabilistic tractography, we studied differences in OR between albinism and controls. Statistical analyses measured white matter integrity in areas corresponding to the OR, as well as LGN to V1 connectivity. Results revealed reduced white matter integrity and connectivity in the OR region in albinism compared to controls, suggesting altered structural development. Previous reports of smaller LGN and the altered thalamo-cortical connectivity reported here demonstrate the effect of misrouting on structural organization of the visual pathway in albinism.
Open Access
Active Observers in a 3D World: Human Visual Behaviours for Active Vision
(2022-12-14) Solbach, Markus Dieter; Tsotsos, John K.
Human-like performance in computational vision systems is yet to be achieved. In fact, human-like visuospatial behaviours are not well understood – a crucial capability for any robotic system whose role is to be a real assistant. This dissertation examines human visual behaviours involved in solving a well-known visual task; The Same-Different Task. It is used as a probe to explore the space of active human observation during visual problem-solving. It asks a simple question: “are two objects the same?”. To study this question, we created a set of novel objects with known complexity to push the boundaries of the human visual system. We wanted to examine these behaviours as opposed to the static, 2D, display-driven experiments done to date. We thus needed to develop a complete infrastructure for an experimental investigation using 3D objects and active, free, human observers. We have built a novel, psychophysical experimental setup that allows for precise and synchronized gaze and head-pose tracking to analyze subjects performing the task. To the best of our knowledge, no other system provides the same characteristics. We have collected detailed, first-of-its-kind data of humans performing a visuospatial task in hundreds of experiments. We present an in-depth analysis of different metrics of humans solving this task, who demonstrated up to 100% accuracy for specific settings and that no trial used less than six fixations. We provide a complexity analysis that reveals human performance in solving this task is about O(n), where n is the size of the object. Furthermore, we discovered that our subjects used many different visuospatial strategies and showed that they are deployed dynamically. Strikingly, no learning effect was observed that affected the accuracy. With this extensive and unique data set, we addressed its computational counterpart. We used reinforcement learning to learn the three-dimensional same-different task and discovered crucial limitations which only were overcome if the task was simplified to the point of trivialization. Lastly, we formalized a set of suggestions to inform the enhancement of existing machine learning methods based on our findings from the human experiments and multiple tests we performed with modern machine learning methods.
Open Access
Active Visual Search: Investigating human strategies and how they compare to computational models
(2024-03-16) Wu, Tiffany; Tsotsos, John K.
Real world visual search by fully active observers has not been sufficiently investigated. Whilst the visual search paradigm has been widely used, most studies use a 2D, passive observation task, where immobile subjects search through stimuli on a screen. Computational models have similarly been compared to human performance only to the degree of 2D image search. I conduct an active search experiment in a 3D environment, measuring eye and head movements of untethered subjects during search. Results show patterns forming strategies for search, such as repeated search paths within and across subjects. Learning trends were found, but only in target present trials. Foraging models encapsulate subject location-leaving actions, whilst robotics models captured viewpoint selection behaviours. Eye movement models were less applicable to 3D search. The richness of data collected from this experiment opens many avenues of exploration, and the possibility of modelling active visual search in a more human-informed manner.
Open Access
Analyizing Color Imaging Failure on Consumer Cameras
(2022-12-14) Tedla, SaiKiran Kumar; Brown, Michael S.
There are currently many efforts to use consumer-grade cameras for home-based health and wellness monitoring. Such applications rely on users to use their personal cameras to capture images for analysis in a home environment. When color is a primary feature for diagnostic algorithms, the camera requires color calibration to ensure accurate color measurements. Given the importance of such diagnostic tests for the users' health and well-being, it is important to understand the conditions in which color calibration may fail. To this end, we analyzed a wide range of camera sensors and environmental lighting to determine (1): how often color calibration failure is likely to occur; and (2) the underlying reasons for failure. Our analysis shows that in well-lit environments, it is rare to encounter a camera sensor and lighting condition combination that results in color imaging failure. Moreover, when color imaging does fail, the cause is almost always attributed to spectral poor environmental lighting and not the camera sensor. We believe this finding is useful for scientists and engineers developing color-based applications with consumer-grade cameras.
Open Access
Anterior Cingulate Cortex Cells Identify Errors of Attentional Control Prior to Prefrontal Disengagement
(2014-07-09) Shen, Chen; Womelsdorf, Thilo
The anterior cingulate cortex (ACC) is implicated in the detection of errors and the allocation of correctional adjustments. However, error detection alone is not sufficient to resolve and prevent future mistakes since errors can occur in various ways, subsequently requiring different adjustments. I therefore investigated whether the ACC tracks specific processing states that give rise to errors in order to identify which specific processing aspects need readjustment. To do this, my lab recorded from cells in the prefrontal cortex (PFC) of macaques while they were performing a selective-attention task that elicited three types of error. My study provides support for the functional role of the ACC in performance monitoring and specifying correctional adjustments through the tracking of specific sources of erroneous task outcomes.
Open Access
Augmented Reality Water-Level Task
(2023-08-04) Abadi, Romina; Allison, Robert
The``Water Level Task'' asks participants to draw the water level in a tilted container. Studies showed that many adults have difficulty with the task. Our study aimed to determine if the misconception about water orientation happens in a more natural environment. We implemented an AR water-in-container effect to create an augmented reality (AR) version of the Water-Level task (AR-WLT). In the AR-WLT, participants interacted with two containers half full of water in a Hololens2 AR display and were asked to determine which looked more natural. In at least one of the two simulations, the water surface did not remain horizontal. A traditional online WLT was created to recruit low and high-scoring participants. Our results showed that low-scoring individuals were likelier to make errors in the AR version. However, participants did not choose simulations close to their 2D drawings, suggesting different cognitive and perceptual factors were involved in different environments.
Open Access
Characterization of the Zebrafish Panx1a Phosphorylation Profile and Interactome in the Regulation of the Channel Function and Trafficking
(2023-03-28) Timonina, Ksenia; Zoidl, Georg R.
Pannexin-1 (Panx1) is an integral membrane protein that forms heptameric channels, involved in the communication between the intracellular and the extracellular environment. Its primary function is to passage small molecules, such as ATP, in and out of the cell, which can trigger vital cellular responses like cell death. Panx1s have been implicated in various diseases, including epilepsy, ischemia, and inflammation. They also play roles in the sensory processing systems, such as vision, hearing, olfaction, and taste. Although it is clear that Panx1s are vital to the function of biological processes, the exact mechanism of how these channels operate and what activates/inactivates them is still under investigation. Using the zebrafish orthologues of Panx1, we explore the structural properties responsible for the trafficking of the channel while maintaining a focus on the phospho-proteomics and the kinase-dependent signaling involving Panx1. We identified a critical residue highly conserved in the third transmembrane domain, Y205 of the zebrafish Panx1a protein, which plays a role in the stabilization of the protein, likely through aromatic-aromatic interactions. Our results show that this residue is not subject to phosphorylation but is vital for the localization of the channel at the cell surface. Using protein purification techniques combined with mass spectrometry analysis, we identified several phosphorylated residues in the cytoplasmic loop of Panx1a and explored the potential interacting kinases of the protein. We studied the interactions between Panx1a with two kinases: ERK2 and CaMKIIa. Our results indicated that a strong interaction exists with CaMKIIa, which plays a role in the trafficking dynamics of Panx1a to the cell membrane. The overexpression of CaMKIIa led to an accumulation of Panx1a in the intracellular compartments. We investigated the effects of various CaMKIIa functional and structural mutants on expression and interaction with Panx1a. We found that the constitutively active T286D CaMKIIa mutant leads to a partial rescue in Panx1a expression, suggesting that Panx1a requires phosphorylation by CaMKIIa for proper cell membrane localization. Together, the research in this thesis provides novel findings that contribute to the phospho-proteomic exploration of Panx1 channel activity and regulation.
Open Access
Color Opponency Modulates Feature Integration Through Bayesian Priors
(2021-11-15) Saini, Harpreet Kaur; Fallah, Mazyar
Stimulus color, even irrelevant to the task, has been shown to modulate high-level cognitive functions, producing different behavioral outcomes. However, the effect of color on lower-level perceptual processes remains unclear. To address this gap, we investigated whether color affects feature integration, an early-stage visual process, using the flash-jump illusion. Our results demonstrated that color modulates the integration of color and motion features, as red and blue flashes resulted in more veridical estimates of flash location, compared to green and yellow. We provide a novel interpretation of our current results in respect to a Bayesian perceptual framework, where the color of the flash is inherently assigned different Bayesian weights, resulting in different levels of perceptual shifts. Furthermore, in reviewing pertinent literature and empirical evidence, we have proposed a novel theory outlining three putative mechanisms, predictions and underlying neural circuitry using Bayesian frameworks to explain such color-dependent modulations in visual processing.
Open Access
Computational Study of Multisensory Gaze-Shift Planning
(2016-11-25) Daemi, Mehdi; Crawford, John Douglas
In response to appearance of multimodal events in the environment, we often make a gaze-shift in order to focus the attention and gather more information. Planning such a gaze-shift involves three stages: 1) to determine the spatial location for the gaze-shift, 2) to find out the time to initiate the gaze-shift, 3) to work out a coordinated eye-head motion to execute the gaze-shift. There have been a large number of experimental investigations to inquire the nature of multisensory and oculomotor information processing in any of these three levels separately. Here in this thesis, we approach this problem as a single executive program and propose computational models for them in a unified framework. The first spatial problem is viewed as inferring the cause of cross-modal stimuli, whether or not they originate from a common source (chapter 2). We propose an evidence-accumulation decision-making framework, and introduce a spatiotemporal similarity measure as the criterion to choose to integrate the multimodal information or not. The variability of report of sameness, observed in experiments, is replicated as functions of the spatial and temporal patterns of target presentations. To solve the second temporal problem, a model is built upon the first decision-making structure (chapter 3). We introduce an accumulative measure of confidence on the chosen causal structure, as the criterion for initiation of action. We propose that gaze-shift is implemented when this confidence measure reaches a threshold. The experimentally observed variability of reaction time is simulated as functions of spatiotemporal and reliability features of the cross-modal stimuli. The third motor problem is considered to be solved downstream of the two first networks (chapter 4). We propose a kinematic strategy that coordinates eye-in-head and head-on-shoulder movements, in both spatial and temporal dimensions, in order to shift the line of sight towards the inferred position of the goal. The variabilities in contributions of eyes and head movements to gaze-shift are modeled as functions of the retinal error and the initial orientations of eyes and head. The three models should be viewed as parts of a single executive program that integrates perceptual and motor processing across time and space.
Open Access
Computer Vision for Hockey Video Curation
(2022-12-14) Pidaparthy, Hemanth; Elder, James
Computer vision-based models are being actively investigated for tasks such as ball and player tracking. These insights are useful for both coaches and players to improve performance. Applying computer vision-based solutions for hockey video analysis is challenging because of the small size of the puck, fast and non-smooth movement of the players, and frequent occlusions. In this thesis, I present my research work on computer vision for hockey video curation. I discuss three problems: 1) automatic sports videography, 2) play segmentation of hockey videos and 3) automatic homography estimation. When recording broadcast hockey videos, professional cameramen move a PTZ camera to follow the play. Professional videography is expensive for amateur games and this motivates the development of a low-cost solution for automatic hockey videography. We used a novel method for accurate ground truth of the puck location from wide-field video. We trained a novel deep network regressor to estimate the puck location on each frame. Centered around the predicted puck location, we dynamically cropped the wide-field video to generate a zoomed-in video following the play. The automatic videography system delivers continuous video over the entire game. Typical hockey games that feature 40-60 minutes of active play are played over 60-110 minutes with breaks in play due to warm-ups and fouls. We propose a novel solution for automatically identifying periods of play and no-play, and generate a temporally compressed video that is easier to watch. We combine visual cues from the output of a deep network classifier with auditory cues from the referee's whistle using a hidden Markov model (HMM). Since the PTZ parameters of the camera are constantly varying when recording broadcast hockey videos, the homography changes every frame. Knowing this homography allows for the projection of graphics onto the ice surface. We estimate the homography by exploiting the consistency of colours used for markings in ice hockey. We model the colours as a multi-variate Gaussian and then use a two-step approach to search for the homography that aligns the colours of the template image to that of a test image.
Open Access
Cortical Mechanisms for Transsaccadic Perception of Visual Object Features
(2021-07-06) Baltaretu, Bianca-Ruxandra; Crawford, John Douglas
The cortical correlates for transsaccadic perception (i.e., the ability to perceive, maintain, and update information across rapid eye movements, or saccades; Irwin, 1991) have been little investigated. Previously, Dunkley et al. (2016) found evidence of transsaccadic updating of object orientation in specific intraparietal (i.e., supramarginal gyrus, SMG) and extrastriate occipital (putative V4) regions. Based on these findings, I hypothesized that transsaccadic perception may rely on a single cortical mechanism. In this dissertation, I first investigated whether activation in the previous regions would generalize to another modality (i.e., motor/grasping) for the same feature (orientation) change, using a functional magnetic resonance imaging (fMRI) event-related paradigm that involved participants grasping a three-dimensional rotatable object for either fixations or saccades. The findings from this experiment further support the role of SMG in transsaccadic updating of object orientation, and provide a novel view of traditional reach/grasp-related regions in their ability to update grasp-related signals across saccades. In the second experiment, I investigated whether parietal cortex (e.g., SMG) plays a general role in the transsaccadic perception of other low-level object features, such as spatial frequency. The results point to the engagement of a different, posteromedial extrastriate (i.e., cuneus) region for transsaccadic perception of spatial frequency changes. This indirect assessment of transsaccadic interactions for different object features suggests that feature sensitive mechanisms may exist. In the third experiment, I tested the cortical correlates directly for two object features: orientation and shape. In this experiment, only posteromedial extrastriate cortex was associated with transsaccadic feature updating in the feature discrimination task, as it showed both saccade and feature modulations. Overall, the results of these three neuroimaging studies suggest that transsaccadic perception may be brought about by more than a single, general mechanism and, instead, through multiple, feature-dependent cortical mechanisms. Specifically, the saccade system communicates with inferior parietal cortex for transsaccadic judgements of orientation in an identified object, whereas as a medial occipital system is engaged for feature judgements related to object identity.
Open Access
Decoding Gating Properties of the Pannexin1 Channel: ATP Release and pH Sensitivity and the Potential Role in Health and Disease
(2015-12-16) Whyte-Fagundes, Paige Alexandra; Zoidl, Georg R.
Panx1 is implicated in disorders including epilepsy and ischemia, with roles in important physiological processes including learning, memory and sensory function. In sensory systems, ATP release and purinergic signaling is considered the most important function of Panx1. Here, the function in the olfactory epithelium was investigated using Panx1 knock out mice. Functional analysis in vivo confirmed a role in olfaction suggesting that Panx1 is one of several alternative ATP release pathways. Since epileptic and ischemic events cause extracellular pH changes, the role of Panx1 in pH sensing was explored next. In a cell model Panx1 showed pH dependent channel gating properties. Site directed mutagenesis and high throughput dye uptake tests revealed a conserved domain of the protein as a pH sensor. Further, the critical role of a single histidine residue in this domain was determined. In summary, these studies demonstrate the role of Panx1 in ATP release and pH sensing.
Open Access
Developing A Non-Human Primate Model To Dissect The Neural Mechanism Of Facial Emotion Processing
(2025-04-10) Taghian Alamooti, Shirin; Kar, Kohitij
Facial emotion recognition is a cornerstone of social cognition, vital for interpreting social cues and fostering communication. Despite extensive research in human subjects, the neural mechanisms underlying this process remain incompletely understood. This thesis investigates these mechanisms using a non-human primate model to provide deeper insights into the neural circuitry involved in facial emotion processing. We embarked on a comparative analysis of facial emotion recognition between humans and rhesus macaques. Using a carefully curated set of facial expression images from the Montreal Set of Facial Displays of Emotion (MSFDE), we designed a series of binary emotion discrimination tasks. Our innovative approach involved detailed behavioral metrics that revealed significant parallels in emotion recognition patterns between the two species. These findings highlight the macaques’ potential as a robust model for studying human-like facial emotion recognition. Building on these behavioral insights, the second phase of our research delved into the neural underpinnings of this cognitive process. We conducted large-scale, chronic multi-electrode recordings in the inferior temporal (IT) cortex of rhesus macaques. By mapping the neural activity associated with the classification of different facial emotions, we uncovered specific neural markers that correlate strongly with behavioral performance. These neural signatures provide compelling evidence for the role of the IT cortex in processing complex emotional cues. Our findings bridge the gap between behavioral and neural perspectives on facial emotion recognition, offering a comprehensive understanding of the underlying mechanisms. This research not only underscores the evolutionary continuity of social cognition across primate species but also sets the stage for future explorations into the neural basis of emotion processing. The integration of behavioral analysis with advanced neural recording techniques presents a powerful framework for advancing our knowledge of social cognition and its disorders.
Open Access
Estradiol extraction and quantification in macaques: development and evalution of sampling methods
Lubinsky, Michael; Hoffman, Kari L.; Tarmakova, Zlatina
Ovarian hormones exert a strong influence on the brain; for example, estradiol (E2) has been found to modulate neuronal plasticity measured in vitro. To develop an understanding of how in vivo neuronal changes relate to the human brain, the non-human primate represents the closest animal model; however, no methodology is currently available for the continual, daily monitoring of E2 using non-human primates. The purpose of this thesis is to develop such a method. Daily sampling from 2 consecutive cycles in each of 3 rhesus macaques indicate that saliva can be used to detect the mid-cycle peaks in E2. Saliva-serum correlations were low, suggesting that further refinement will be needed to increase this method's applicability to measures that require off-peak daily E2 fluctuations. An example includes the measurement of E2 concentration in conjunction with electrophysiology, to monitor the influence of estradiol levels on neural activity.
Open Access
Examining Autoexposure for Challenging Scenes
(2024-03-16) Yang, Beixuan; Brown, Michael S.
Autoexposure (AE) is a critical step cameras apply to ensure properly exposed images. While current AE algorithms are effective in well-lit environments with unchanging illumination, these algorithms still struggle in environments with bright light sources or scenes with abrupt changes in lighting. A significant hurdle in developing new AE algorithms for challenging environments, especially those with time-varying lighting, is the lack of platforms to evaluate AE algorithms and suitable image datasets. To address this issue, we have designed a software platform allowing AE algorithms to be used in a plug-and-play manner with the dataset. In addition, we have captured a new 4D exposure dataset that provides a complete solution space (i.e., all possible exposures) over a temporal sequence with moving objects, bright lights, and varying lighting. Our dataset and associate platform enable repeatable evaluation of different AE algorithms and provide a much-needed starting point to develop better AE methods.
Open Access
Exploring the Cellular and Molecular Mechanisms Driving Connexin-36 Electrical Plasticity and the Functional Consequences of its Loss on the Sensorimotor Behaviors of Zebrafish (Danio Rerio)
(2022-12-14) Brown, Cherie Alicia; Zoidl, Georg R.
In mammals, connexin-36 (Cx36) is the major component of electrical synapses, also found alongside chemical synapses throughout the brain. An equivalent form of long-term potentiation (LTP) exclusively at Cx36 electrical synapses, termed the run-up, has been previously identified; however, the mechanism and molecular machinery involved remains elusive. We hypothesized an LTP-like mechanism was involved at Cx36 electrical synapses, potentiating the run-up. To address this, we investigated the tubulin-dependent delivery of Cx36 connexons to the plasma membrane in Neuro2a cells. A putative Cx36-tubulin binding motif was elucidated via sequence alignment, and the direct binding of tubulin with the C-terminal tail of Cx36 was confirmed via BioID. TIRF and FRAP microscopy techniques established that Cx36 is transported from the trans-Golgi network to the plasma membrane via interactions with the tubulin-cytoskeleton. Manipulating the Cx36-tubulin interaction via mutations and pharmacological inhibition reduced Cx36 trafficking to the gap junction plaque and inhibited run-up. While we identified tubulin as a driving force in achieving Cx36 run-up, we found that its transport occurred independently of CaM-CaMKII activity. Despite the similarities in machinery used between chemical and electrical synapses, the functional consequence of Cx36 asymmetry at homotypic aggregates had yet to be addressed. Next, we investigated the role of Cx36 in sensorimotor circuitry in zebrafish (Danio rerio), where the teleost orthologs are expressed distinctly. Here, we targeted the gjd2b gene since its corresponding ortholog, Cx35b, is expressed presynaptically. Based on current literature, we hypothesized that complex alterations to neuronal circuitry via Cx35b knock-out (KO) would affect vision, sensorimotor gating, and plasticity-dependent cognitive processing. We found that Cx35b expression coincides with photoreceptor cell specificity and expression in the inner plexiform layer. Cx35b KO resulted in developmental deviances, cranial defects, visual ambiguities (discrimination of light stimulus brightness, arrangement, and temporal properties), and increased levels of anxiety; however, KO did not impair non-associative learning and memory. Genetically, loss of the gjd2b gene resulted in changes primarily in connexin, dopaminergic, and immediate early gene regulation. Taken together, we concluded that Cx36 shares molecular machinery with chemical synapses to rectify neuronal communication, and this molecular asymmetry is critical in driving behavioral outcomes.
Open Access
Exploring the Impact of Immersion on Situational Awareness and Trust in Remotely Monitored Maritime Autonomous Surface Ships
(2023-03-28) Gregor, Alexander William Heinz; Allison, Robert
This thesis examines how Situational Awareness (SA) and Trust, along with some exploratory variables, were affected by different immersion levels in maritime remote monitoring. To examine this a simulated Shore Control Centre (SCC) interface for Maritime Autonomous Surface Ships (MASS) was constructed, which had an autonomous container ship traversing the arctic with robotic aids. Three query sets were asked per simulation run, which facilitated tracking how SA, Trust, and Motion Sickness (MS) evolved over time. Three different virtual reality (VR) interfaces were used; Non-Immersive VR (NVR), Semi-immersive VR (SVR), and Immersive VR (IVR). The simulation and query sets were performed on a counterbalanced within-subjects user study with 39 participants. The results illustrated various trade-offs - with NVR showing higher user preference, SVR showing signs of higher SA, and IVR showing moderate Trust but increased MS. Understanding these trade-offs between immersion levels is a requisite step for designing future SCCs.
Open Access
Eye-Head-Hand Coordination During Visually Guided Reaches in Head-Unrestrained Macaques
(2020-05-11) Arora, Harbandhan Kaur; Crawford, John Douglas
Our goal was to determine if reaching influences eye-head coordination (and vice versa) in Rhesus macaques. Eye, head, and hand motion were recorded in two animals using search coil and touch screen technology, respectively. Animals were seated in a customized chair which allowed unencumbered head motion and reaching in depth. In the reach condition, animals were trained to touch a central LED at waist level while maintaining central gaze and were then rewarded if they touched a target appearing at one of 15 locations. In other variants, initial hand or gaze position were varied in the horizontal plane. In similar control tasks, animals were rewarded for gaze accuracy. In the reach task, animals made eye-head gaze shifts toward the target followed by reaches that were accompanied by prolonged head motion toward the target. This resulted in significantly larger velocities and final ranges of head position compared with the gaze control.

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