Two schematic drawings of coronal sections of human brain labelling the basal ganglia. Blue=striatum, green=globus pallidus (external and internal segments), yellow=subthalamic nucleus, red=substantia nigra (pars reticulata and pars compacta). The right section is the deeper one, closer to the back of the head.
Images taken from wikipedia from the out of copyright Gray's anatomy. Basal ganglia location
Original file: http://commons.wikimedia.org/wiki/File:Telencephalon-Horiconatal.jpgBasal ganglia (coronal)
Permission: GFDL
Original file: http://commons.wikimedia.org/wiki/File:Basal-ganglia-coronal-sections-large.pngDopamine in PDThe image shows dopaminergic pathways of the human brain in normal condition (left) and Parkinsons Disease (right). Red Arrows indicate suppression of the target, blue arrows indicate stimulation of target structure.
Permission: GNU free
Original file: http://commons.wikimedia.org/wiki/File:DA-loops_in_PD.jpg