A5101866391- Visual perception and processing mechanisms
- Orthopaedic implants and arthroplasty
- Hip disorders and treatments
- Olfactory and Sensory Function Studies
- Visual Attention and Saliency Detection
- Neural dynamics and brain function
- Neural and Behavioral Psychology Studies
- Gaze Tracking and Assistive Technology
- Vestibular and auditory disorders
- Cardiac Valve Diseases and Treatments
- EEG and Brain-Computer Interfaces
- Musculoskeletal synovial abnormalities and treatments
- Total Knee Arthroplasty Outcomes
- Advanced Battery Technologies Research
- Color perception and design
- Multisensory perception and integration
- Advanced DC-DC Converters
- Shoulder and Clavicle Injuries
- Shoulder Injury and Treatment
- Glaucoma and retinal disorders
- CCD and CMOS Imaging Sensors
- Knee injuries and reconstruction techniques
- Lower Extremity Biomechanics and Pathologies
- Sensor Technology and Measurement Systems
- Tactile and Sensory Interactions
Western Orthopedics Foundation
2015-2025
Queen's University
2011-2024
Swedish Medical Center
2024
Porter Adventist Hospital
2020-2022
Denver School of Nursing
2020
New York University Langone Orthopedic Hospital
2005-2016
Justus-Liebig-Universität Gießen
2005-2010
St. James's Hospital
2008
University of British Columbia
1970-2007
Models of visual attention postulate the existence a saliency map whose function is to guide and gaze most conspicuous regions in scene. Although cortical representations have been reported, there mounting evidence for subcortical mechanism, which pre-dates evolution neocortex. Here, we conduct strong test hypothesis by comparing output well-established computational model with activation neurons primate superior colliculus (SC), midbrain structure associated gaze, while monkeys watched...
The orienting reflex is initiated by a salient stimulus and facilitates quick, appropriate action. It involves rapid shift of the eyes, head, attention other physiological responses such as changes in heart rate transient pupil dilation. SC critical structure midbrain that selects incoming stimuli based on saliency relevance to coordinate behaviors, particularly gaze shifts, but its causal role dilation remains poorly understood mammals. Here, we examined primate control dynamics. While...
Models of visual attention postulate the existence a bottom-up saliency map that is formed early in processing stream. Although studies have reported evidence various cortical brain areas, determining contribution phylogenetically older pathways crucial to understanding its origin. Here, we compared coding from neurons two gateways into system: primary cortex (V1) and evolutionarily superior colliculus (SC). We found that, while response latency stimulus onset was earlier for V1 than...
The tremendous increase in the use of video-based eye tracking has made it possible to collect data from thousands participants. traditional procedures for manual detection and classification saccades trial categorization (e.g., correct vs. incorrect) are not viable large datasets being collected. Additionally, trackers allow analysis pupil responses blink behaviors. Here, we present a detailed description our pipeline collecting, storing, cleaning data, as well organizing participant codes,...
Color is important for segmenting objects from backgrounds, which can in turn facilitate visual search complex scenes. However, brain areas involved orienting the eyes toward colored stimuli our environment are not believed to have access color information. Here, we show that neurons intermediate layers of monkey superior colliculus (SC), a critical structure production saccadic eye movements, respond isoluminant with same magnitude as maximum contrast luminance stimulus. In contrast,...
Abstract Here we examined the influence of visual response in superior colliculus (SC) (an oculomotor control structure integrating sensory, motor and cognitive signals) on development command that drives saccadic eye movements monkeys. We varied stimulus luminance to alter timing magnitude responses SC how these changes correlated with resulting saccade behavior. Increasing target resulted multiple modulations response, including increased decreased onset latency. These signal strongly...
Spontaneous eye blinking is gaining popularity as a proxy for higher cognitive functions, it readily modulated by both environmental demands and internal processes. Prior studies were impoverished in sample size, sex representation, age distribution, making difficult to establish complete picture of the behavior. Here we present eye-tracking data from large cohort normative participants ( n = 604; 393 F; aged 5–93 years) performing two tasks: one with structured, discrete trials (interleaved...
Labral repair has been shown to be an effective treatment option with excellent early outcomes; however, in cases of severe labral damage or when the tissue is too large diminutive, may less effective. The purpose this article present a modified technique for hip reconstruction using iliotibial band allograft and front-to-back fixation technique. described from original report arthroscopic reconstruction. allows surgeon make graft that longer than necessary cut excess after fixation,...
PurposeTo assess the outcomes of complete, primary, arthroscopic hip labral reconstruction among patients aged 40 years and older compared with those who underwent primary repair 30 to 39 reconstruction.MethodsWe recruited all between March 2010 June 2015 were 65 or 2009 years. The modified Harris Hip Score (mHHS), Lower Extremity Function Score, visual analog scale score for average pain collected preoperatively at minimum 2-year follow-up. Failure was defined as need revision ipsilateral...
Abstract During natural viewing, the trajectories of saccadic eye movements often deviate dramatically from a straight-line path between objects. In human studies, saccades have been shown to toward or away salient visual distractors depending on visual- and goal-related parameters, but neurophysiological basis for this is not well understood. Some studies suggest that deviation associated with competition simultaneously active sites within intermediate layers superior colliculus (SC),...
Abstract Objectives This study (1) describes and compares saccade pupil abnormalities in patients with manifest alpha-synucleinopathies (αSYN: Parkinson’s disease (PD), Multiple System Atrophy (MSA)) a tauopathy (progressive supranuclear palsy (PSP)); (2) determines whether rapid-eye-movement sleep behaviour disorder (RBD), prodromal stage of αSYN, already have abnormal responses that may indicate risk for developing PD or MSA. Methods Ninety (46 RBD, 27 PD, 17 MSA) an 10 PSP patients, 132...
The primary function of the superior colliculus (SC) is to orient visual system toward behaviorally relevant stimuli defined by features such as color. However, a longstanding view has held that activity in SC arises exclusively from achromatic pathways. Recently, we reported evidence primate highly sensitive signals originating chromatic pathways, but these are delayed relative luminance (White et al., 2009). Here, describe functional consequence this difference arrival time on processes...
This review describes the normal patellofemoral joint and detail mechanism anatomic elements that predispose patients to patellar instability. The treatment options for both acute chronic injuries are described rationale behind their approach this problem is explained. In general, most dislocations should be treated nonoperatively unless instability associated with an osteochondral injury. Chronic dislocators based on understanding of patient's individual reason recurrent achieved a thorough...
Abstract Purpose: Patients who have experienced failure of arthroscopic labral reconstruction the hip traditionally been left with limited options, such as living pain and dysfunction, or undergoing arthroplasty. The purpose our study was to evaluate outcomes revision circumferential allograft (CLR) in nonarthritic hips which had previously undergone by same surgeon. Method: Data from 24 (∼ 1% lead author’s surgical panel during a 4-year collection period) were evaluated determine efficacy...
Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain significant LED current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit effect on light. designs novel control techniques aim loads dc voltage ensure limited low-frequency ripple. This paper proposes an average modulation method that is designed operate in conjunction PF correction (PFC) circuits ripple, while maintaining zero allows capacitance...
The purpose of this study is to investigate the outcomes from anchor-induced chondral damage hip, both with and without frank penetration. A multicenter retrospective case series was performed patients deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, outcome scores descriptions treatment in cases requiring revision surgery anchor removal are reported. Five (three females) mean age 32 years (range, 16–41 years) had...