Mn-Enhanced MRI of Neural Activity in the mouse Midbrain

Manganese (Mn)-Enhanced MRI (MEMRI) has been proposed as a method to visualize neuronal activity in animals, taking advantage of the permeability of voltage-gated calcium channels to Mn2+. We tested the sensitivity of MEMRI to detect activation of the mouse auditory system, imaging mice with 3D T1-weighted spin echo MRI at defined time points after intra-peritoneal (IP) injection of MnCl2 and exposure to repetitive auditory stimulation. This easily-implemented protocol resulted in significant (10-15%) MEMRI enhancement in the auditory midbrain, compared to deafened control mice, showing the efficacy of MEMRI for detecting auditory-evoked neural activity in the mouse brai