Publications by authors named "Edmond Fitzgibbon"

Manipulations of the strength of visual motion coherence have been widely used to study behavioral and neural mechanisms of visual motion processing. Here, we used a novel broadband visual stimulus to test how the strength of motion coherence in different spatial frequency (SF) bands impacts human ocular-following responses (OFRs). Synthesized broadband stimuli were used: a sum of one-dimensional vertical sine-wave gratings (SWs) whose SFs ranged from 0.

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Objective: To investigate the effects of oral baricitinib on ocular surface disease (OSD) in patients with chronic graft-versus-host disease (cGVHD).

Design: Prospective phase 1 to 2 single institution trial.

Subjects: Eighteen patients with ocular graft-versus-host-disease (oGVHD) and systemic steroid-refractory cGVHD.

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In this paper, we show that the model we proposed earlier to account for the disparity vergence eye movements (disparity vergence responses, or DVRs) in response to horizontal and vertical disparity steps of white noise visual stimuli also provides an excellent description of the short-latency ocular following responses (OFRs) to broadband stimuli in the visual motion domain. In addition, we reanalyzed the data and applied the model to several earlier studies that used sine-wave gratings (single or a combination of two or three gratings) and white noise stimuli. The model provides a very good account of all of these data.

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Importance: Since 2015, US government and related personnel have reported dizziness, pain, visual problems, and cognitive dysfunction after experiencing intrusive sounds and head pressure. The US government has labeled these anomalous health incidents (AHIs).

Objective: To assess whether participants with AHIs differ significantly from US government control participants with respect to clinical, research, and biomarker assessments.

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Two-frame kinematograms have been extensively used to study motion perception in human vision. Measurements of the direction-discrimination performance limits (Dmax) have been the primary subject of such studies, whereas surprisingly little research has asked how the variability in the spatial frequency content of individual frames affects motion processing. Here, we used two-frame one-dimensional vertical pink noise kinematograms, in which images in both frames were bandpass filtered, with the central spatial frequency of the filter manipulated independently for each image.

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Natural images are typically broadband, whereas detectors in early visual processing are selective for narrow ranges of spatial frequency. White noise patterns are widely used in laboratory settings to investigate how responses are derived from Fourier components in the image. Here, we report disparity vergence responses (DVRs) to white noise stimuli in human subjects and compare these with responses to white noise patterns filtered with bandpass filters and notch filters and to sinusoidal gratings.

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Background: Patients with cryptococcal meningitis (CM) often have ocular manifestations; although data are describing these findings in nonimmunosuppressed, previously healthy individuals are scarce.

Methods: A retrospective chart review was performed for previously healthy patients with CM who underwent a complete ophthalmological examination within a 5-year period at the National Institutes of Health. Demographics, CSF parameters, findings on initial ophthalmological examination, and MRI abnormalities were analyzed.

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Adult-onset histiocytoses (AOH), primarily Rosai-Dorfman disease (RDD), Erdheim-Chester Disease (ECD), and adult Langerhans cell histiocytosis (ALCH), are a group of related histiocytic neoplastic disorders featuring multisystemic manifestations. The disorders are largely incurable, and are essentially chronic neoplastic diseases with a variable prognosis. Prompt diagnosis and treatment is important to prevent debilitating and even life-threatening complications.

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This article reports quantitative measurements of intracranial volume, optic canal area, and peripapillary retinal nerve fiber layer (RNFL) for a cohort of 124 patients with craniofacial fibrous dysplasia/McCune-Albright Syndrome (FD/MAS), previously used to determine risks for developing optic disc edema [1]. Of these, 7 subjects were diagnosed with optic disc edema. OSIRIX imaging analysis software was used to collect intracranial volume and optic canal diameter for 107 patients, via 3D multiplanar reconstruction (MPR) of ≤5 mm axial CT slices.

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Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations.

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Neuronal and psychophysical responses to a visual stimulus are known to depend on the preceding history of visual stimulation, but the effect of stimulation history on reflexive eye movements has received less attention. Here, we quantify these effects using short-latency ocular following responses (OFRs), a valuable tool for studying early motion processing. We recorded, in human subjects, the horizontal OFRs induced by drifting vertical 1D pink noise.

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Background: Cryptococcal meningoencephalitis (CM) is a major cause of mortality in immunosuppressed patients and previously healthy individuals. In the latter, a post-infectious inflammatory response syndrome (PIIRS) is associated with poor clinical response despite antifungal therapy and negative cerebrospinal fluid (CSF) cultures. Data on effective treatment are limited.

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Background: Fibrous dysplasia (FD) is a rare disorder of expansile fibro-osseous lesions that may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Optic disc edema is a potentially serious ophthalmologic finding that has been rarely reported in patients with FD/MAS. The purpose of this study was to investigate the prevalence and potential clinical associations of optic disc edema in a large cohort.

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Article Synopsis
  • The study aims to detail the eye-related symptoms in patients with sialidosis type I caused by a deficiency in the enzyme neuraminidase 1, while also introducing a new method for analyzing the 'macular cherry-red spot' using advanced imaging techniques.
  • Seven patients with sialidosis type I and one with galactosialidosis underwent comprehensive eye exams, revealing that all had a distinct macular cherry-red spot, good corneal clarity, and varied visual acuity.
  • Results showed that most patients maintained decent vision into adulthood, although those with optic atrophy had poorer outcomes; increased reflectivity in macular imaging was observed across the board, providing new insights for monitoring disease progression.
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Optic neuropathy (ON) is a highly disabling complication of fibrous dysplasia (FD). The optimal test for identifying and monitoring ON in FD is unknown. Optical coherence tomography (OCT) is an imaging modality that detects retinal nerve fiber layer (RNFL) thinning, a sign of optic nerve atrophy.

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Fibrous dysplasia (FD) is a benign bone disease characterized by expansile lesions that typically stabilize with age. Rarely, FD can undergo malignant transformation, presenting with atypical, rapid growth and destruction of adjacent bone. Other potential causes of rapid FD expansion include secondary lesions, such as aneurysmal bone cysts.

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In this study, we used a novel imaging technique, DTI (diffusion tensor imaging)-driven tensor-based morphometry, to investigate brain anatomy in subjects diagnosed with Moebius syndrome ( = 21), other congenital facial weakness disorders ( = 9) and healthy controls ( = 15). First, we selected a subgroup of subjects who satisfied the minimum diagnostic criteria for Moebius syndrome with only mild additional neurological findings. Compared to controls, in this cohort, we found a small region of highly significant volumetric reduction in the paramedian pontine reticular formation and the medial longitudinal fasciculus, important structures for the initiation and coordination of conjugate horizontal gaze.

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We recorded horizontal ocular-following responses to pairs of superimposed vertical sine wave gratings moving in opposite directions in human subjects. This configuration elicits a nonlinear interaction: when the relative contrast of the gratings is changed, the response transitions abruptly between the responses elicited by either grating alone. We explore this interaction in pairs of gratings that differ in spatial and temporal frequency and show that all cases can be described as a weighted sum of the responses to each grating presented alone, where the weights are a nonlinear function of stimulus contrast: a nonlinear weighed summation model.

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Fundal abnormalities, including preretinal and retinal changes, are a rare finding in patients with the autosomal recessive lysosomal storage disorder Gaucher disease, most often described in patients with the chronic neuronopathic form (type 3). We evaluated whether these ophthalmological findings correlated with other manifestations of type 3 Gaucher disease. Reviewing the records of 40 patients with type 3 Gaucher disease, we identified five with white vitreous opacities and reviewed their clinical course in depth.

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Background: Action and perception should be coordinated for good visual-motor performance. The mechanism coupling action and perception may be a prominence map in the intermediate layer of the superior colliculus that modulates motor and attentional/perceptual processes. This coordination comes with a cost: the misperception that briefly overlapping stimuli are separated in time.

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From a mathematical point of view, extracting motion and disparity signals from a binocular visual stream requires very similar operations, applied over time for motion and across eyes for disparity. This similarity is reflected in the theories that have been proposed to describe the neural mechanisms used by the brain to extract these signals. At the behavioral level there are, however, several differences in how humans react to these stimuli, which presumably reflect differences in how these signals are processed by the brain.

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Gaucher disease is an autosomal recessive lysosomal storage disorder caused by mutations in the gene GBA1, which encodes the lysosomal protein glucocerebrosidase. Patients with Gaucher disease generally have a variety of clinical manifestations ranging from visceral to neurological involvement and some develop ocular involvement. The most commonly affected organs include the spleen, liver, and bone.

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Purpose: Stereoscopic vision, by detecting interocular correlations, enhances depth perception. Stereodeficiencies often emerge during the first months of life, and left untreated can lead to severe loss of visual acuity in one eye and/or strabismus. Early treatment results in much better outcomes, yet diagnostic tests for infants are cumbersome and not widely available.

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