Layer-Specific fMRI of Visual Stimulation in the Rat Retina: Responses to Different Stimulation Luminance, Frequency & Color

Yen-Yu Ian Shih¹, Bryan H. De La Garza¹, Eric R. Muir¹, Li Guang¹, Timothy Q. Duong¹

This study reports a novel application of very high resolution (60 m) fMRI using MION at an 11.7 T scanner to image the rat retina associated with various visual stimulations. The retinal layer responses to flickering light of different luminance, frequency and wavelength were greater than in the choroidal layer. The retinal layer responses were dependent on luminance, frequency and wavelength revealing characteristic tuning curves, whereas the outer layer responses were not, suggesting differential neurovascular coupling between the two vascular layers. This is the first report of vascular layer-specific fMRI during visual stimulation in the retina in vivo.