Change the green background to white in the upper-left area of the brain and remove most of the small leaves in that space, while keeping the long branches with leaves. In the upper-left area of the brain, remove the loose and individual leaves along the edge, but keep the leaves that are part of branches, leaving only a few within that space. Remove the roots in the lower-right area. Insert the Psi (Ψ) symbol into the design as a very thin 3D element, outlined in black, with colors that match the brain region it crosses. The symbol should be the size of the brain and appear as a single unified design, dividing the brain into four parts, with each part retaining its original colors and patterns.