functional mri

[drgregory]

several of my optometrist colleagues have been working with a group of radiologists using functional MRI to correlate retinal ganglion cell loss/vision loss in patients with glaucoma. i was wondering if anyone has any experience with functional mri technology. in theory, is seems it has a future. however, my knowledge of the imaging aspect is limited. anyone have any thoughts on this?

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[Neuronix]

I don't work in BOLD fMRI per se, but I would be concerned that fMRI wouldn't be sensitive enough to pick up changes in the retina. The retinal cell layer is barely visible on MRI (see http://www.ncbi.nlm.nih.gov/entrez/..._uids=16523482&query_hl=2&itool=pubmed_docsum) and fMRI usually tries to capture signal changes in the few percent range. I also don't know how if the retina has dilatory blood vessels that allow for BOLD contrast. i.e. fMRI looks at blood flow changes to active areas, and not the metabolism in that area directly.

You would likely see changes in the visual cortex and other macroscopic vision processing areas. There is robust activation of V1 in people with vision who are shown things like flashing lights or other stimulations. However, I don't know if you could find someting new that hasn't been published, and I leave that for you to determine.

For understanding fMRI, I've found this book helpful. It goes into alot of nice detail about all the experiments showing how fMRI works.
http://www.amazon.com/gp/product/05...ref=sr_1_2/102-5685024-7028950?_encoding=UTF8

Good luck...

 

[drgregory]

I don't work in BOLD fMRI per se, but I would be concerned that fMRI wouldn't be sensitive enough to pick up changes in the retina. The retinal cell layer is barely visible on MRI (see http://www.ncbi.nlm.nih.gov/entrez/..._uids=16523482&query_hl=2&itool=pubmed_docsum) and fMRI usually tries to capture signal changes in the few percent range. I also don't know how if the retina has dilatory blood vessels that allow for BOLD contrast. i.e. fMRI looks at blood flow changes to active areas, and not the metabolism in that area directly.

You would likely see changes in the visual cortex and other macroscopic vision processing areas. There is robust activation of V1 in people with vision who are shown things like flashing lights or other stimulations. However, I don't know if you could find someting new that hasn't been published, and I leave that for you to determine.

For understanding fMRI, I've found this book helpful. It goes into alot of nice detail about all the experiments showing how fMRI works.
http://www.amazon.com/gp/product/05...ref=sr_1_2/102-5685024-7028950?_encoding=UTF8

Good luck...

thanks for the info and great links.