The ex vivo SN imaging protocol was optimized for high resolution histological comparisons and enhanced SN-associated MRI contrasts. For the T2*WI, an echo time of TE = 15.4 ms yielded the best MRI visual contrast among the 10 different TEs, ranging from 3.1 to 40 ms (Supplementary Figure S4). All MRI scans displayed visible contrasts between the SN and surrounding structures. The T1WI images presented more distinct boundaries than the T2* weighted sequences, which appeared as arch shapes between the SN and the crus cerebri. However, the magnetization transfer T1WI could not visually depict NM-related contrasts in the SNc as previously reported with 3T MRI23789.