Optimizing Negative fMRI Response in the Rat Striatum Under Isoflurane Anesthesia

Yen-Yu Ian Shih¹, Shiliang Huang¹, Timothy Q Duong¹

Subcortical activation in anesthetized animal models is challenging. This study introduces a novel approach to evoke negative fMRI response in the rat striatum using forepaw stimulation under isoflurane anesthesia, allowing longitudinal investigation of striatal function. The fMRI responses to nine different stimulus pulse durations of forepaw were analyzed. Robust positive fMRI responses were observed in the contralateral primary somatosensory cortex, but bilateral negative fMRI responses were observed in the striatum. We also demonstrate this approach on a unilateral focal ischemia. Our findings make survival animal fMRI with robust subcortical responses become reality.