The present invention makes a grid array, for use in the transplantation of materials into the brain, in the shape of a predetermined structure, such as the putamen, based on anatomic analysis the structure. Alternatively, a smaller grid array is used which only includes the putamen target and not the caudate target, and also has two windows within the grid array. Because of the smaller size of this grid array as well as the two cutouts in the middle, it is possible for the first time to observe the brain as the needle enters the brain through the grid array. The previous solid and larger grid array made the passage of the needle into the brain a blind maneuver. Therefore if there was cortical bleeding at the time of needle insertion, it would not be known until after the transplant was done.