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Study on the Spatial-temporal Properties of Striate Cortical Cells in Strabismic Amblyopia

Author: LiuHu
Tutor: ZhaoKanXing
School: Tianjin Medical University
Course: Ophthalmology
Keywords: Strabismus Amblyopia Visual cortex Visual development Receptive field Synaptic plasticity
CLC: R777.44
Type: PhD thesis
Year: 2004
Downloads: 232
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Abstract

Research purposes using extracellular recording techniques, blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) technology, immunohistochemistry techniques and stereological methods to explore the temporal characteristics of the strabismic amblyopia visual cortex neurons change their mechanisms, from In many ways, the deep-seated reveals possible mechanisms of strabismus amblyopia. Research methods (1) to scan the sinusoidal grating stimuli, extracellular recording technology to detect the 10 normal cats, 17 strabismic (6 mild, seven moderate, 4 severe) striate cortex cells discharge levels . Qualitative research a normal cat, strabismic eyes of the cortical cells that drive the cell and distribution of ocular dominance columns; The quantitative comparison strabismic two drive cortical cells optimal spatial frequency, time, frequency, and its integration time. (2) the use of different spatial frequencies Othello disk grid flip collected 15 cases of strabismus amblyopia stimulation, GE1.5T magnetic resonance imaging system, and 10 normal whole brain BOLD-fMRI data. Conduct of visual cortex functional position; quantitative comparison strabismic amblyopia the normal cortex eyes pixel indices and strabismic amblyopia two drive the average level of activity of cortical neurons; BOLD-fMRI signal strength and vision. (3) 5-HT _2C R monoclonal antibodies were used to detect the different developmental time frame eight normal development of the cat, 8 strabismus cat visual cortex Area 17 5-HT _2C R expression. Quantitative comparison of the normal development of the cat with strabismus cat visual cortex Area 17 5-HT _2C R in the first three weeks after birth, 6 weeks, 9 weeks and 6 months of age differential expression. (4) application of transmission electron microscopy, stereological analysis methods were used to detect the four normal development of the cat, four strabismic Cortical Area 17 in the number of synapses and synaptic structure parameter changes. The quantitative comparison of the normal development of the cat with strabismic Cortical Area 17 in the number of synaptic density, synaptic cleft width, the thickness of the postsynaptic density, synaptic active zone length and synaptic interface curvature differences. Tianjin Medical University Doctoral Dissertation Research Results (l) the strabismic visual cortex eyes reduce drive cells than normal cat. Distribution of ocular dominance columns associated with the degree of amblyopia: severe amblyopia ocular dominance columns shift to the contralateral eye, no significant transfer of mild to moderate amblyopia ocular dominance columns. Compared with the contralateral eye, strabismus amblyopia amblyopic eye to drive cortical cells optimal spatial frequency, integration time down, two optimal time frequency tuning differences not significant. (2) normal people with strabismus amblyopia occipital visual cortex, Ying gyrus, posterior parietal has a different level of excitement. The major excitatory located calcarine fissure around the occipital visual cortex, compared with normal, strabismic amblyopia not only excited area decreases, the eyes pixel Index decreased. Selection of high spatial frequency stimuli drive the average level of activity of cortical neurons than the contralateral eye reduce the amblyopic eye. More than vision and cortical BOLD to commit signal strength no correlation. (3) the normal development of the cat visual cortex yuan 5 H few cR expression to build a clear and structured. In the spatial distribution, the layers of the visual cortex are visible the 5 ^{H TZeR staining positive cells, its expression to n W layer signal is relatively strong, weak expression signals of V Vl layer. At the time of the distribution, of 5 a HTZcR the expression level increased with age and reached a peak in the first six weeks after birth, and then gradually decline to 6-month-old cat (adult cat) a few cR expression and 9-week-old cat close. Compared with the normal cat, the strabismic amblyopia 5 a H cR of expression level decreased, its after birth, the first six weeks, nine weeks, and 6 months of age differences in the levels of the cat 5.HTZeR expression without significant resistance. (4) the normal development of the cat visual cortex synapses to the shaft a tree synaptic dominant presynaptic composition containing clear round vesicles or granular vesicles. In addition, one synapse visible shaft dendritic spinous process touch, axis. Strabismic shaft dendritic touched significantly reduced the number of dendritic spines, dendritic short branch area decreases dendritic spines, spines stems shorter. The synaptic morphology parameters study found that the normal development of the cat visual cortex synaptic interface curvature increases, there is a growing trend, laugh and worry-type synaptic. Compared with the normal development of the cat, the the strabismic amblyopia synapses before and after the film interface is reduced, the decline in the length of the active region, the postsynaptic density significantly thinner, wider synaptic cleft. The conclusion (l) the strabismic amblyopia visual function damage with two abnormal interaction as well as spatial and temporal characteristics of the amblyopic eye driver visual cortical neurons and their integration of external information related to abnormal. The strabismic amblyopia cortex damage not only limited to the primary visual cortex, the extrastriate cortex there are also abnormal features. Gan Tianjin Medical University PhD thesis (2) strabismus amblyopia morphological changes manifested as the reduction in the number of synapses and synaptic changes in the structure of Cortical Area 17. (3) 5 H few cR important factor regulation visual development sensitive period plasticity strabismic amblyopia, as the structural basis of the functional changes not only at the cellular level, and also performed at the molecular level. (4) the possible mechanisms of strabismus amblyopia: the eyes receptive field of the development of early strabismus abnormal visual attention change trigger the two abnormal interaction between strabismus afferent reduce a visual cortical neurons in neural circuits within , the outer environment factors change (neurotransmitters and neuromodulators, receptors, etc.) ^{based long-term potentiation of synaptic plasticity changes ^{sudden Touch the number and structure of dysplasia, the final performance for the visually-impaired visual function changes. (5) amblyopia medication for synaptic plasticity intervention will provide new ideas and fertile Pa.}}}

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CLC: > Medicine, health > Ophthalmology > Ocular adnexal organ disease > Ocular disease and strabismus > Amblyopia
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