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Abstract #3682

Optogenetically Induced BOLD of Excitatory Neurons in the Mouse Hippocampus at 9.4T: Identification of a Hippocampal Network

Wolfgang Weber-Fahr1, Alexander Sartorius2, Natlia Gass1, Zhijun Li3, Wolfgang Kelsch2,3

1Neuroimaging, Central Institute of Mental Health, Mannheim, Germany; 2Psychiatry, Central Institute of Mental Health, Mannheim, Germany; 3Clinical Neurobiology, Ruprecht-Karls-Universitt, Heidelberg, Germany

It was shown recently in rats that BOLD activation in a particular region can be caused by optogenetic stimulation. In this study we were interested in the hippocampal network in mice and induced expression of channelrhodopsin-2 in Ca2dependent protein kinase II-expressing neurons by viral injection. Laser stimulation was periodically applied through an optical fiber in the left hippocampus with a block design while fMRI data was aquired. We found activation in a large area of the targeted hippocampus. Interestingly, we also we found a corresponding significant activation in areas outside the stimulated region in the primary somatosensory and motor cortices.