Functional magnetic resonance imaging evaluation of visual cortex activation in patients with anterior visual pathway lesions

The aim of this study was to examine the secondary visual cortex functional disorder in patients with glaucoma and large pituitary adenoma by functional magnetic resonance imaging, and to determine the correlation between visual field defect and primary visual cortex activation. Results showed that single eye stimulation resulted in bilateral visual cortex activation in patients with glaucoma or large pituitary adenoma. Compared with the normal control group, the extent and intensity of visual cortex activation was decreased after left and right eye stimulation, and functional magnetic resonance imaging revealed a correlation between visual field defects and visual cortex activation in patients with glaucoma and large pituitary adenoma. These functional magnetic resonance imaging data suggest that anterior optic pathway lesions can cause secondary functional disorder of the visual cortex, and that visual defects are correlated with visual cortex activation.

Inflammation in the anterior visual pathway in multiple sclerosis:what do the animal models teach us?

A provocative and overly reductive mantra is that"the back of the eye is the front of the brain".Retinal imaging techniques that take advantage of this"window"to the central nervous system can provide valuable information regarding injury to the nervous system with relative ease and with a limited burden to patients.The retina develops embryonically as part of the neuroectoderm,is made up principally of neurons and their supporting cells,and is synaptically tied to the central nervous system(CNS).This has led to significant interest in using retinal health as a biomarker for brain health-given the relatively limited accessibility of brain tissue in chronic neurodegenerative diseases that progress over decades.The retina is not truly part of the CNS,and as with much of brain imaging-the grounds for asserting the pathological specificity of retinal imaging is limited.Biophotonics-based methods such as optical coherence tomography indirectly provide an opportunity to evaluate retinal neurodegeneration,while autopsy studies,histology and immunohistochemistry predominate as the methods that collect direct pathological data.Our understanding of pathological retinal lesions characteristic of demyelinating diseases,specifically diseases showing anterior visual pathway involvement,has grown significantly in recent years.However,much of the underlying pathobiology of injury remain unexplored.This review aims to highlight the major pathological features of the retina in multiple sclerosis,and its most used animal models(experimental autoimmune encephalomyelitis and cuprizone),with a particular focus on n the role of inflammation.