-
Orthodontics & Craniofacial Research Nov 2012To construct three-dimensional (3D) horizontal reference planes based on visual pathway and to determine their stability and reliability by analyzing the structural...
OBJECTIVES
To construct three-dimensional (3D) horizontal reference planes based on visual pathway and to determine their stability and reliability by analyzing the structural patterns of normal and dysmorphology for 3D craniofacial analysis.
SETTING AND SAMPLE POPULATION
Thirty-six subjects with maxillofacial dysmorphology and malocclusion, and eight normal controls. MATERIALS AND METHODS POPULATION: On the 3D computed tomographic images of the subjects, the visual pathway-based planes, including the orbital axis plane (OAP), visual axis plane (VAP), and the optical axis plane (OpAP), were constructed and evaluated.
RESULTS
The OAP, but not the VAP and OpAP, showed the ideal relationship between the midsagittal and posterior maxillary plane, and properly described the different patterns of maxillofacial dysmorphology with craniofacial plane 1 of Delaire's analysis and the occlusal plane.
CONCLUSIONS
The proposed visual pathway-related horizontal reference planes, and in particular the OAP, seem to correctly express the visual axis and the position of the head in natural head position and can be used as a horizontal reference plane for the 3D analysis of craniofacial dysmorphology and anthropology.
Topics: Case-Control Studies; Cephalometry; Craniofacial Abnormalities; Face; Head; Humans; Imaging, Three-Dimensional; Orbit; Posture; Reference Standards; Reproducibility of Results; Tomography, X-Ray Computed; Visual Pathways
PubMed: 23020695
DOI: 10.1111/j.1601-6343.2012.01551.x -
Journal of Neurophysiology Mar 2017The human ventral visual pathway is implicated in higher order form processing, but the organizational principles within this region are not yet well understood....
The human ventral visual pathway is implicated in higher order form processing, but the organizational principles within this region are not yet well understood. Recently, Lafer-Sousa, Conway, and Kanwisher ( 36: 1682-1697, 2016) used functional magnetic resonance imaging to demonstrate that functional responses in the human ventral visual pathway share a broad homology with the those in macaque inferior temporal cortex, providing new evidence supporting the validity of the macaque as a model of the human visual system in this region. In addition, these results give new clues for understanding the organizational principles within the ventral visual pathway and the processing of higher order color and form, suggesting new avenues for research into this cortical region.
Topics: Animals; Brain Mapping; Color Perception; Form Perception; Humans; Macaca; Magnetic Resonance Imaging; Species Specificity; Visual Cortex; Visual Fields; Visual Pathways; Visual Perception
PubMed: 27358320
DOI: 10.1152/jn.00358.2016 -
Indian Journal of Ophthalmology Jan 2019
Topics: Child; Humans; Magnetic Resonance Imaging; Male; Optic Nerve; Optic Nerve Diseases; Visual Acuity; Visual Pathways; Visual Perception
PubMed: 30574913
DOI: 10.4103/ijo.IJO_256_18 -
European Journal of Radiology Jan 2004This brief systemic overview presents the anatomic details of the orbit with respect to imaging modalities CT and MR. The structures of the four orbital compartments,... (Review)
Review
This brief systemic overview presents the anatomic details of the orbit with respect to imaging modalities CT and MR. The structures of the four orbital compartments, intrakonal and extrakonal space, globe and optic nerve are demonstrated in detail on different CT and MR views (axial, coronal, in soft tissue and bone window, T1-weighted, T2-weighted) with corresponding diagrams. The intracranial visual pathway is explained in detail with emphasis to the striate cortex and extrastriate visual association cortex, presented with diagrams and high-resolution MR.
Topics: Humans; Magnetic Resonance Imaging; Orbit; Tomography, X-Ray Computed; Visual Cortex; Visual Pathways
PubMed: 14982083
DOI: 10.1016/j.ejrad.2003.11.001 -
Journal of Molecular Neuroscience : MN Jun 2022A change in visual perception is a frequent early symptom of multiple sclerosis (MS), the pathoaetiology of which remains unclear. Following a slow demyelination process...
A change in visual perception is a frequent early symptom of multiple sclerosis (MS), the pathoaetiology of which remains unclear. Following a slow demyelination process caused by 12 weeks of low-dose (0.1%) cuprizone (CPZ) consumption, histology and proteomics were used to investigate components of the visual pathway in young adult mice. Histological investigation did not identify demyelination or gliosis in the optic tracts, pretectal nuclei, superior colliculi, lateral geniculate nuclei or visual cortices. However, top-down proteomic assessment of the optic nerve/tract revealed a significant change in the abundance of 34 spots in high-resolution two-dimensional (2D) gels. Subsequent liquid chromatography-tandem mass spectrometry (LC-TMS) analysis identified alterations in 75 proteoforms. Literature mining revealed the relevance of these proteoforms in terms of proteins previously implicated in animal models, eye diseases and human MS. Importantly, 24 proteoforms were not previously described in any animal models of MS, eye diseases or MS itself. Bioinformatic analysis indicated involvement of these proteoforms in cytoskeleton organization, metabolic dysregulation, protein aggregation and axonal support. Collectively, these results indicate that continuous CPZ-feeding, which evokes a slow demyelination, results in proteomic changes that precede any clear histological changes in the visual pathway and that these proteoforms may be potential early markers of degenerative demyelinating conditions.
Topics: Animals; Cuprizone; Disease Models, Animal; Mice; Mice, Inbred C57BL; Multiple Sclerosis; Proteins; Proteomics; Visual Pathways
PubMed: 35644788
DOI: 10.1007/s12031-022-01997-w -
The Journal of Experimental Biology Oct 1990The development of the mammalian visual system begins prenatally at distributed sites, where cells generated at different embryonic ages are destined to interconnect and... (Review)
Review
The development of the mammalian visual system begins prenatally at distributed sites, where cells generated at different embryonic ages are destined to interconnect and form the visual pathways, and ends postnatally with the functional tuning of neuronal receptive-field properties. It is reasonable to assume that the earliest stages in this developmental sequence are completed prior to the onset of neural activity, and also that activity may play only a minor role or even none at all in primary axon outgrowth and pathway finding (Harris, 1981; Harris and Holt, 1990). However, recent evidence indicates that subsequent events in development, such as the sorting of axons at their targets, the cellular differentiation of target cells and the formation of synaptic contacts by developing axons, are all influenced by action potentials. Action potentials in the developing retino-geniculo-cortical pathway can be eliminated by blocking the voltage-gated sodium channel with tetrodotoxin. Prenatal blockade prevents the laminar segregation of retinogeniculate axons. Postnatal blockade interrupts the formation of retinogeniculate synaptogenesis, slows the cytoarchitectonic differentiation of the lateral geniculate nucleus and produces abnormalities in the responses of lateral geniculate neurons. In the visual cortex, the development of cells and synapses is retarded and the eye-specific separation of geniculocortical axons is halted, thereby blocking the formation of ocular dominance columns. While the cellular mechanisms underlying these effects are not understood, a partial restoration of normal development can be produced by stimulating blocked axonal pathways electrically.
Topics: Action Potentials; Aging; Animals; Axons; Geniculate Bodies; Mammals; Retina; Synapses; Visual Cortex; Visual Pathways
PubMed: 2280224
DOI: 10.1242/jeb.153.1.261 -
Neuron Apr 2012Visual area V4 is a midtier cortical area in the ventral visual pathway. It is crucial for visual object recognition and has been a focus of many studies on visual... (Review)
Review
Visual area V4 is a midtier cortical area in the ventral visual pathway. It is crucial for visual object recognition and has been a focus of many studies on visual attention. However, there is no unifying view of V4's role in visual processing. Neither is there an understanding of how its role in feature processing interfaces with its role in visual attention. This review captures our current knowledge of V4, largely derived from electrophysiological and imaging studies in the macaque monkey. Based on recent discovery of functionally specific domains in V4, we propose that the unifying function of V4 circuitry is to enable selective extraction of specific functional domain-based networks, whether it be by bottom-up specification of object features or by top-down attentionally driven selection.
Topics: Animals; Attention; Macaca; Mental Processes; Visual Cortex; Visual Pathways; Visual Perception
PubMed: 22500626
DOI: 10.1016/j.neuron.2012.03.011 -
European Journal of Paediatric... 2002Visual pathway gliomas occur predominantly in young children. Chemotherapy has been increasingly used as a first-line treatment because of the complications caused by...
Visual pathway gliomas occur predominantly in young children. Chemotherapy has been increasingly used as a first-line treatment because of the complications caused by radiotherapy and surgery. Nine children between 6 months and 9 years (median age of 4.8 years) were treated with vincristine and carboplatin according to the SIOP (Société Internationale d'Oncologie Pédiatrique) low-grade glioma 1996 protocol. Five patients had evidence of neurofibromatosis type 1. Magnetic resonance imaging (MRI) and ophthalmological assessment were performed during and after treatment. There was a positive response in all children (100%). Three patients developed progressive disease between 8 and 12 months after ceasing treatment. One of them, being only 2.5 years old, was again treated by chemotherapy with partial response on MRI. Patients with neurofibromatosis type 1 never developed progressive disease. Our data suggest that chemotherapy is an effective treatment option in young children with visual pathway gliomas. MRI is an important means of monitoring the tumour response provided that a rigid imaging protocol is used to detect the early tumoral changes.
Topics: Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Carboplatin; Child; Child, Preschool; Female; Follow-Up Studies; Glioma; Humans; Infant; Magnetic Resonance Imaging; Male; Vincristine; Visual Acuity; Visual Fields; Visual Pathways
PubMed: 12374587
DOI: 10.1053/ejpn.2002.0595 -
Investigative Ophthalmology & Visual... Sep 2019White matter (WM) degeneration of the visual pathways in primary open-angle glaucoma (POAG) is well documented, but its exact pathophysiology remains unclear. To date,...
PURPOSE
White matter (WM) degeneration of the visual pathways in primary open-angle glaucoma (POAG) is well documented, but its exact pathophysiology remains unclear. To date, glaucomatous WM degeneration has been exclusively studied using diffusion tensor imaging (DTI) only. However, DTI measures lack direct biological interpretation, and the approach itself suffers from multiple technical limitations. Fixel-based analysis (FBA) is a novel framework for studying WM degeneration, overcoming DTI's technical limitations and providing biologically meaningful metrics. FBA measures fiber density (FD), representing early microstructural changes, and fiber-bundle cross section (FC), representing late macrostructural changes. In this study, we use FBA to study glaucomatous degeneration of the pregeniculate optic tracts (OTs) and postgeniculate optic radiation (ORs) in POAG.
METHODS
This was a cross-sectional case-control study with 12 POAG patients and 16 controls. Multi-shell diffusion-weighted images were acquired. FBA was used to produce a population template, and probabilistic tractography was used to track the OTs and ORs in template space. Finally, FD and FC of the tracts of interest were compared between the two groups.
RESULTS
Compared with the controls, the OTs of the patients exhibited a significant (familywise error corrected P < 0.05) decrease in FD and FC, whereas their ORs exhibited a significant decrease in FD but not in FC.
CONCLUSIONS
FBA provides sensitive measures to assess WM changes in glaucoma. Our findings suggest that the OTs of glaucoma patients exhibit signs of more advanced WM degeneration compared with the ORs. This potentially implicates anterograde trans-synaptic propagation as the primary cause of glaucomatous spread along the visual pathways.
Topics: Aged; Case-Control Studies; Cross-Sectional Studies; Diffusion Magnetic Resonance Imaging; Female; Glaucoma, Open-Angle; Humans; Leukoencephalopathies; Male; Middle Aged; Nerve Fibers; Retinal Ganglion Cells; Visual Pathways; White Matter
PubMed: 31504081
DOI: 10.1167/iovs.19-27447 -
Brain Research Bulletin Jan 2017The primary visual pathway exhibits a symmetrical anatomical structure, initially arising from the left and right retinas, passing through the lateral geniculate...
The primary visual pathway exhibits a symmetrical anatomical structure, initially arising from the left and right retinas, passing through the lateral geniculate nucleus, and finally projecting to the left and right primary visual cortices. However, to our knowledge, studies based on scalp EEG have not provided adequate evidence of the functional symmetry of the primary visual pathway, as the usual visual ERP is often related to other higher-level brain areas. Steady-state visual evoked potentials (SSVEPs) can be considered as the direct response of the primary visual pathway to a repetitive stimulus, with a very limited correlation with responses of higher-level brain areas. Therefore, SSVEPs can be used to evaluate the functional symmetry of the primary visual pathway. In this study, we draw a comparison among the powers and distributions of SSVEPs of different frequencies when the left or right eye alone is stimulated, and when both the eyes are stimulated together. Our results indicate that the primary visual pathway is almost symmetrical in generating SSVEPs from either eye and that there is some functional interaction between the left and right primary visual pathways.
Topics: Cerebrum; Electroencephalography; Evoked Potentials, Visual; Functional Laterality; Humans; Vision, Binocular; Vision, Monocular; Visual Pathways; Visual Perception
PubMed: 27845170
DOI: 10.1016/j.brainresbull.2016.11.005