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GERALD SCHNEIDER: We have a question from a student at the beginning here asking me to clarify what I meant by fixed action pattern. Do you remember what a fixed action pattern was? We were talking about behavior. We said it was an instinctive movement. Basically, it's an ecological term of-- from zoology. The ecologists in the field of zoology originated this study of inherited behavior patterns, OK? Humans have many of them, and all animals. Their behavior patterns there are pretty similar from one member of the species to the other because the basic pattern is inherited. Brain structures develop under genetic control and form the circuits necessary for these patterns. It would include, in humans, things like crying and smiling and frowning, and looking down when you're a little shy, and things like that. There have been cross-cultural studies of human. There's a very nice book on human ecology by [INAUDIBLE],, if any of you are interested. And there's a...

GERALD SCHNEIDER: We're still on this first topic, primitive cellular mechanisms. And we'll be on that for the entire session today, talking mainly about secretion in neurons. We started that before, when we talked about excitatory and inhibitory postsynaptic potentials and summation effects. Is action at a synapse always one way? Well, if it's a chemical synapse, the information flows always in one direction. It doesn't mean there's nothing that goes the other direction. There is some communication, but the electrical changes generally are going one direction. There are such things as electrical synapses. They're not very common in the mammalian nervous system, where the action can go in both ways. We talked about Otto Loewi. And remember, he discovered some pretty good evidence for chemical transmission at synapses. He was in the peripheral nervous system, the autonomic nervous system, working with the innervation of the frog heart. And what was ...

GERALD SCHNEIDER: OK. We're just finishing up the introductory lectures before we start discussing neurons in more detail. We've talked about now these three major types of goals of people trying to explain behavior, neurological terms. And I want to say more about the modern subsystems approach today. And as I mentioned last time, as we go through this, sometimes difficult to keep in mind that neurons are a lot more complex than our little diagrams of reflexes indicate. I want to introduce the use of the subsystems approach. I want to go back to Carl Wernicke and show you how we can put his theory into an information flow diagram. He was 1874, and this is the picture I showed you before. Let's-- can you see how this is really a reflexological model of speech? Note here that we're speaking a word that you see-- reading in other words, reading aloud-- how is this a reflex model? Every reflex model starts with a stimulus. What's the stimulus? It's vi...

GERALD SCHNEIDER: So we want to finish the auditory system today. And then we'll get into the topic of pain and the limbic system. I had gone through rather complicated connections of the subcortical auditory system, pointing out that there are two major streams of information flow, one concerning more with identity of the stimulus, and particularly concerned with temporal patterns. And we'll see more about that today when we talk about the cortical regions, which is represented in this diagram here. Here, we have the primary sensory neurons connected to the receptor cells-- the hair cells in the cochlea-- going to the two cochlear nuclei, the dorsal and ventral, where you have a number of different neuron types, some of which project, particularly for this ventral stream concerned with spatial localization, project to the cell groups in the trapezoid body. There's at least three cell groups there-- the nucleus of the trapezoid body, or medial nucleus the trap...

GERALD SCHNEIDER: OK, what is the Betz cell, and where is it? A few of you were asking questions about that at the end of the last lecture, so I thought I would start with it today. What kind of a cell is it? That kind of question in neuroscience has several different types of answers. First of all, it's a neuron, the main cell that communicates in the central nervous system or in the peripheral nervous system. But another answer would be it's a certain type of neuron. It's a pyramidal cell in the neocortex. Betz cells are in the major output layer that is output to non-cortical sources. So now, I don't know how much you know even what neocortex is and what subcortical sources means, but you will be learning, OK? Don't worry about it if you don't understand something when I first mention it. Anything, especially in anything neuroanatomical, that I expect you to know I will repeat and add to the information a number of times, OK? It won't be som...