Magnetic Resonance Imaging of Mouse Brain Networks Plasticity Following Motor Learning

In vivo MRI was performed twice (time interval ~25 days) on a 9.4 Tesla vertical bore NMR spectrometer (Bruker Biospin, Billerica, MA) using a 20 mm diameter volume coil as the radiofrequency transmitter and receiver. Images were acquired using a three-dimensional (3D) T2-weighted fast spin echo sequence (FSE) with: echo time (TE)/repetition time (TR) = 40/700 ms, 16 mm x 16 mm x 16 mm field of view, and 128 x 128 x 80 matrix (resolution = 0.125 mm × 0.125 mm × 0.2 mm, echo train length = 4, number of average = 2, flip angle = 40°, bandwidth (BW)=100 kHz).

Ex vivo MRI-DTI of brain specimens was performed on the same 9.4 T NMR spectrometer and a 15 mm diameter volume coil. Images were acquired using a diffusion weighted 3D gradient and spin echo sequence with: TE = 33 ms, TR = 900 ms, BW= 100 kHz, and 4 averages. The FOV and matrix size were 13.0 mm x 10.0 mm x 18.4 mm and 128 x 96 x 180, resulting in a native resolution of 0.1 mm x 0.1 mm x 0.1 mm. 6 diffusion-weighted images (b value =1700 s/mm2) and 2 non-diffusion-weighted images were acquired.