Ophthalmology and Bioengineering

METHODS: Animal Preparation: Adult male Syrian hamsters (130-175 g, N= 17) were divided into 3 groups. In the first 2 groups, the optic tract was deafferented at the brachium of the left superior colliculus (BSC)(1) as in Figure 1. 30µL of saline (Group 1, n= 6) or 1% SAPNS solution (Group 2, n= 5) was applied to the site of transection respectively right after BSC cut, and 1H MRS was performed on each side of the SC at 3, 14, and 28 days after treatment. Six age-matched normal hamsters were scanned as controls in Group 3.

MATERIALS AND METHODS: Animal Preparation: Sprague-Dawley rats (12-16 g, N= 7) underwent unilateral ligation of the left common carotid artery at postnatal day 7 under isoflurane anaesthesia, followed by hypoxia in 8% oxygen and 92% nitrogen at 36-37oC for 2 hours. Two and a half months after HI insults, T1WI, T2WI and DTI were performed to all animals.

Animal models of neonatal monocular enucleation has been used to study developmental mechanisms underlying visual perception, due to its extensive changes and reorganization in various parts of the visual system1. It has also been used to investigate the cross-modal changes in the central nervous system caused by early loss of the visual input2, 3. As a consequence of visual deprivation, experimental evidence suggests that there are neurophysiological changes in the visual cortex4.

Abstract This paper demonstrated our recent use of contrast-enhanced MRI, diffusion tensor/kurtosis imaging, proton magnetic resonance spectroscopy, and functional MRI techniques, for in vivo and global assessments of the structure, metabolism and function of the visual system in rodent studies of ocular diseases, optic neuropathies, developmental plasticity and neonatal hypoxic-ischemic brain injury at 7T.

Abstract This study aims to employ in vivo dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to evaluate the ocular transport following an induction of ocular hypertension in a rat model of chronic glaucoma. Upon systemic administration of Gd-DTPA solution, T1-weighted signal increase was observed in the vitreous body of the glaucomatous eye but not the control eye. This increase occurred earlier in the anterior vitreous body than the preretinal vitreous.

The superior colliculus (SC) is a dome-shaped subcortical laminar structure in the mammalian midbrain, whose superficial layers receive visual information from the retina in a topological order. Despite the increasing number of studies investigating retinotopic projection in visual brain development and disorders, in vivo, high-resolution 3D mapping of topographic organization in the subcortical visual nuclei has not yet been available.

It is generally accepted that cognitive processes, such as learning and memory, are affected in depression. The present study used a rat model of depression, chronic unpredictable mild stress (CUMS), to determine whether hippocampal volume and neurochemical changes were involved in learning and memory alterations.