Florian Schmid1, Lydia Wachsmuth1, Franziska Albers1, Nathalie Just1, Miriam Schwalm2, Albrecht Stroh2, and Cornelius Faber1
1Department of Clinical Radiology, University of Münster, Münster, Germany, 2Research Group Molecular Imaging and Optogenetics, Johannes Gutenberg-University Mainz, Mainz, Germany
Optogenetic fMRI is a novel
tool in neurophysiology and neuroimaging. However, ofMRI is prone to
light-induced artifacts. Here, the unspecific activation of the visual pathways
in ofMRI in rats was investigated. It was caused by the stimulation light and was
also detected in naïve rats without the presence of opsins. Visual stimulation of the eyes resulted in
similar activation. Visual pathway activation by intrabrain illumination could
be suppressed by additional low-level constant light applied to the eyes. We
provide evidence that the activation of the visual pathways is at least partly
caused by light scattered diffusely inside the brain.
