Effect of induced high myopia on functional MRI signal changes

Mahmoud-Pashazadeh, Ali and Mirzajani, Ali and Rasuli, Behrouz and Ghorbani, Mohammad (2017) Effect of induced high myopia on functional MRI signal changes. Physica Medica, 37. pp. 32-36.

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Official URL: https://www.ncbi.nlm.nih.gov/pubmed/28535912


Purpose The current study evaluated the effect of lens-induced high myopia (IHM) on the activity of the occipital visual cortex during two visual stimuli presentations to the subjects. This was done by measuring the Blood Oxygenation Level Dependent (BOLD) signal using functional MRI (fMRI). Methods BOLD contrast fMRI was performed with a 1.5T MRI scanner on 12 emmetropic subjects (refractive error <±0.25Diopter) with no history of neurologic disorder. IHM conditions were applied to subjects by three convex lenses of +5D, +7D and +10D. Visual stimuli with 0.34 cpd and 1.84 cpd spatial frequencies (SF) were presented as a block paradigm to the participants in three IHM states and normal vision state during fMRI data acquisition. Resultant fMRI data were compared among different refractive states. Results Data analysis showed that IHM did not cause a significant change in the visual cortex activity throughout the presentation of 0.34 cpd SF visual stimulus and BOLD signal intensity remained approximately constant (p = 0.17). Although, fMRI responses to visual stimuli with spatial frequency of 1.84 cpd demonstrated that visual cortex activity was significantly reduced in IHM states compared to normal vision (p = 0.01), the results showed no significant differences between three different values of IHM. Conclusions This study shows severe blurring caused by lens induced high myopia can decrease BOLD signal intensity depending on the visual stimulus pattern details. However in the low and moderate range of spatial frequencies, blur increment from +5D up to +10D is not associated with further reduction in the BOLD signal of the occipital visual cortex.

Item Type: Article
Subjects: WN Radiology . Diagnostic Imaging
Divisions: Research Center > Persian Gulf Nuclear Medicine Research Center
Depositing User: زهرا صفایی
Date Deposited: 31 Dec 2018 08:37
Last Modified: 31 Dec 2018 08:37
URI: http://eprints.bpums.ac.ir/id/eprint/7434

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