Early visual deafferentation of the cortex results in an asymmetry of somatostatin labelled cells

1987 ◽  
Vol 67 (3) ◽  
Author(s):  
G. Jeffery ◽  
J.G. Parnavelas
Keyword(s):  
Visual Deafferentation

FDG-PET Scanning Shows Distributed Changes in Cortical Activity Associated with Visual Hallucinations in Eye Disease

2019 ◽  
Vol 19 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Lütfü Hanoglu ◽  
Sultan Yildiz ◽  
Tansel Cakir ◽  
Taha Hanoglu ◽  
Burak Yulug
Keyword(s):  
Visual Cortex ◽  
Fdg Pet ◽  
Underlying Mechanism ◽  
Posterior Cingulate Cortex ◽  
Eye Disease ◽  
Visual Hallucinations ◽  
Charles Bonnet Syndrome ◽  
Pet Scanning ◽  
Inferior Parietal Cortex ◽  
Visual Deafferentation

Background and Objective: Charles Bonnet Syndrome (CBS) has been defined as complex visual hallucinations (CVH) due to visual loss. The underlying mechanism of CBS is not clear and the underlying pathophysiology of the visual hallucinations in CBS patients and pure visually impaired patients is still not clear. </P><P> Methods: In our study, we have scanned three patients with eye disease and CBS (VH+) and three patients with eye disease without CBS (VH-) using FDG-PET. Results: Our results showed underactivity in the pons and overactivity in primary right left visual cortex and inferior parietal cortex in VH- patients and underactivity in left Broca, left inf frontal primary visual cortex and anterior and posterior cingulate cortex in VH+ patients relative to the normative 18FFDG PET data that was taken from the database consisting of 50 age-matched healthy adults without neuropsychiatric disorders. Conclusion: From this distributed pattern of activity changes, we conclude that the generation of visual hallucination in CBS is associated with bottom-up and top-down mechanism rather than the generally accepted visual deafferentation-related hyperexcitability theory.

Effect of visual deafferentation on the direct cortical response

1969 ◽  
Vol 3 (3) ◽  
pp. 91-98
Author(s):  
N. N. Zislina ◽  
N. A. Arkhipova
Keyword(s):  
Cortical Response ◽  
Direct Cortical Response ◽  
Visual Deafferentation

scholarly journals Neurochemical changes in the pericalcarine cortex in congenital blindness attributable to bilateral anophthalmia

2015 ◽  
Vol 114 (3) ◽  
pp. 1725-1733 ◽  
Author(s):  
Gaelle S. L. Coullon ◽  
Uzay E. Emir ◽  
Ione Fine ◽  
Kate E. Watkins ◽  
Holly Bridge
Keyword(s):  
Gray Matter ◽  
Large Scale ◽  
Occipital Cortex ◽  
Resonance Spectroscopy ◽  
Cortical Region ◽  
Structural Reorganization ◽  
Congenital Blindness ◽  
Visual Deafferentation ◽  
Biochemical Profiles ◽  
Neurochemical Changes

Congenital blindness leads to large-scale functional and structural reorganization in the occipital cortex, but relatively little is known about the neurochemical changes underlying this cross-modal plasticity. To investigate the effect of complete and early visual deafferentation on the concentration of metabolites in the pericalcarine cortex, 1H magnetic resonance spectroscopy was performed in 14 sighted subjects and 5 subjects with bilateral anophthalmia, a condition in which both eyes fail to develop. In the pericalcarine cortex, where primary visual cortex is normally located, the proportion of gray matter was significantly greater, and levels of choline, glutamate, glutamine, myo-inositol, and total creatine were elevated in anophthalmic relative to sighted subjects. Anophthalmia had no effect on the structure or neurochemistry of a sensorimotor cortex control region. More gray matter, combined with high levels of choline and myo-inositol, resembles the profile of the cortex at birth and suggests that the lack of visual input from the eyes might have delayed or arrested the maturation of this cortical region. High levels of choline and glutamate/glutamine are consistent with enhanced excitatory circuits in the anophthalmic occipital cortex, which could reflect a shift toward enhanced plasticity or sensitivity that could in turn mediate or unmask cross-modal responses. Finally, it is possible that the change in function of the occipital cortex results in biochemical profiles that resemble those of auditory, language, or somatosensory cortex.

C 25: Thalamo-Cortical Rhythmicity During Reversible Visual Deafferentation

1970 ◽  
Vol 80 ◽  
pp. 44A-44A ◽  
Author(s):  
S. Andersson ◽  
E. Holmgren ◽  
T. Ivarsson
Keyword(s):  
Visual Deafferentation
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