In this lecture, we're going to speak about the basal ganglia or basal nuclei. It depends on the textbook which phrase you're going to hear. I'm going to talk about them as the basal nuclei because they're a group of neurons within the central nervous system that function together with common targets, common inputs, and common neurotransmitters. In the Haynes textbook, is when you might run across, he calls them basal nuclei, and so I'm too. Basal nuclei really are the neural basis of habits. We define habits as sequential, repetitive motor behaviors elicited by external, internal triggers. Once activated, these behaviors are completed without constant conscious oversight. For example, once you start walking, you don't have to think about walking, you can check your cell phone, you can listen to music, you can chew gum, you can do all kinds of things while you're walking because it's a habitual sequential motor behavior. These are the different components of the basal nuclei that we'll be discussing in the next part of this lecture. The caudate and putamen are both part of the brain called the striatum. The globus pallidus is part of the pallidum. The substantia nigra or brown spot is found within the brain stem, and the subthalamic nucleus is part of the diencephalon. We haven't talked about the diencephalon very much, we will in a subsequent lecture. But just a foreshadow, the diencephalon is all things thalamus. So the subthalamic nucleus is part of the diencephalon. In the next set of slides, I'm going to show you what these nuclei look like within coronal and horizontal sections of the brain.