Good day everyone and welcome back. In our last sections we have been talking about how the brain works and how the neurons work. In this section we are going to talk about how drugs specifically target specific brain structures.

So let's begin by going to slide two. As you can see here, there are a variety of different structures that we talked about in the first major group of material related to the brain. You will see the frontal lobe where it is involved with movement. You will also see in the frontal lobe structures involved with judgment.  Further, you have the reward system with the hypothalamus, the memory system with the hippocampus, the orange one associated with coordination is the cerebellum. The occipital lobe involved with vision, and of course the sensation system which is associated with the parietal lobe.

Slide three shows us a picture of the different types of structures related to a neuron. As we can see here, there is the soma, dendrites, the axon , and the terminal button which is more correctly called the presynaptic element.

Slide four actually shows a synapse.  Specifically the connection between one neuron with its axon connecting to another neuron's dendrite and that information going on the axon of the second neuron.

Slide five shows a variety of different brain structures that are important in relation to substance abuse. These have been discussed a little earlier.   As you can see, the hypothalamus is in a green color, the neocortex in a yellowish color, basal ganglia in purple, the amygdala in red, and of course the hippocampus is associated with the dark blue.

On slide six there is a set of structures, the ventral tegmental area (VTA) which is located within the thalamus, the nucleus accumbens, and the prefrontal cortex. These sets of structures and a couple of others make up what is called the medial forebrain bundle.  You will hear me talk about that over and over again throughout the rest of this course. The medial forebrain bundle is your primary reward system that you have in the brain, and this structure is highly loaded with dopamine neurons. As you can probably tell, dopamine is extremely important in reward pathways.

There are some other important structures as well (shown in slide seven). These are receiving circuits that will be sending information into the medial forebrain bundle and into the structures we have discussed previously.

Picture eight shows a variety of different structures that are impacted by many different drugs. It can impact the movement system in the frontal lobe, it can impact judgment systems, and on, and on, and on.

Picture number nine shows a variety of different structures associated with the major function of what they do. As you can see, the prefrontal cortex is highly important with judgment and assorted other things as well as movement. The VTA and the nucleus accumbens associated with reward and the hippocampal formation with memory and on, and on, and on.

Finally, structure ten is extremely important in understanding pain. The finger represents something that you touch. That information is then going to go up into the brain, after it goes through the thalamus, it is going to go into the parietal lobe, then to the frontal lobe, come back down, and then move some structure (usually a muscle). All these different things, again, are tied into each other. So when you impact one by drugs it basically impacts the others as well. For example, if you take a drug that basically shuts down your sensory system it is going to impact your motor system as well.

Well, that concludes this section regarding the overview of different types of brain structures. In our next section we are going to talk about how drugs enter and travel through and are metabolized by the system. So until then we hope you have yourself a great day.

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