2007-09-13

The behaving brain and the responding brain. In the behaving brain, they talk about brain surgery, brain structures, and in the Responding Brain, it talks about responses of the brain and how the brain adapts to its environment. The video shows some stuff that is in your book, as well as experiments with baboon and rats and so on. This is just a flip flop on our schedule. Tomorrow you will have the "Teenage Brain" video with a substitute.

The brain looks like couliflower, and it may look like couliflower, but it's a very complex structure. Perhaps the most complex structure in the universe. There are as many cells in our brain as stars in our galaxy - about 10 trillion. Although they come in more than 200 different types, these neurons are all designed to just do three things: receive information, process information, and transmit it to the rest of the body. All behavior begins with neuronal action. First, it gathers information from receptors on dendrites, and next the information is sent to the neuronal cell body (soma) where it is combined with other incoming information. Then, the entire input is cast along via electrical neural impulse over the axon. The impulse ends up at the axon's terminal button. These buttons contain neurotransmitters that are chemical messages to adjacent neurons (across the synapse). Although kept tightly together, no two neurons actually touch, and they must send messages over the synapse / synaptic gap, since they do not touch. These chemical messages are called neurotransmitter. When these are released, it attaches to specific receptor sites on neighboring dendrites, like a key on a lock. Some synapses are excitatory - the neurotransmitters cause the neuron to generate a nerve impulse. While other synapses are inhibitory- they produce or prohibit nerve impulses.

The receptor channels in the dendirtes determine the effect of the neurotransmitters as the sum of all of the excitatory and inhibitory inputs, the next neuron is fired at a certain rate. This constant flow of messages, gives human behavior its incredible complexity. It regulates our metabolism, temperature, and respiration. It enables us to learn, remember, and decide. What's so difficult to comprehend is that, somehow, within these nerve cells and synapses, is the basis of communicating all that we can possibly know and experience, and how this happens, is a profound study for our neuroscientists.

Neuroscientists are guided by the assumption that everything that the brain does is explainable by the biological/chemical events within it, even in particular regions. These researchers, understanding behavior means knowing its biological foundation. The brain is an integral part of the nervous system, and it works in a holisitc way with all of its parts interacting. There are some regions that are specialized. Let's take a quick tour.

The brain stem connects the brain to the nerves in the spinal cord, and is the center for breathing, beating of the heart, waking, sleeping, etc., and connected to the brain stem at the back of the skull is the cerebellum which maintains posture, equilibrium, etc. Deep within the brain is the limbic system- it makes up the old mammalian brain, it maintains temperature, sugar levels, blood pressure, and it regulates emotion, the powerful drives of sexual desire and self-motivation. The hippocampus, the hypothalamus, and the thalamus are the most important parts of the limbic system. The hippocampus matches new information to information already stored in the brain, and some kinds of memories. The hypothalamus acts as a leiason to the body and the rest of the brain, releasing hormones to the pituitary gland, which releases hormones into the blood stream, regulating growth and sex. The thalamus is a relay station, sending signals from the body to the rest of the brain.

Then there's the cerebrum- the largest part of the human brain. It is here that nerve impulses get translated into symbols, pictures, words, ideas, and concepts. The cerebrum is divided into two cerebral hemispheres, which are connected by millions of neurons via the Corpus collosum, a conduit for communication between the two sides. The outer layer of the cerebrum is the cortex- the conscious thinker, the top management, and brain hierarchy.

To probe the secrets of the brain requires many methods. The earliest information came from patients with brain damage. Then there was lesioning, the precise destruction of brain tissue to see if it correlated with loss of behavior, or stimulating the brain with chemicals or electricity. Today, the latest approach is brain imaging, which can image structure and functure. It provides people with actual pictures of the brain's inner workings. The most wide-spread technique is to record the brain's electrical activity. Because neurons are biochemical electrical generators, neuroscientists have figured out how to record a signal from a single neuron. The electrical activity of the entire brain can be recorded via electroencephalogram which represents total activity.

Neurometrics- precise neuropsychological measurement of neural functionality. "We have looked at the electrical activity of the human brain, ... and described the electrical captivity quantitatively via computer analysis. What we found is that this electrical activity changes in an orderly way, which can be described by equations. The basics of neurometrics is that every individual's neural activity can be compared to normative data collected across the lifespan, and this comparison is statistical, and the data is presented in a way that is supposed to attract your attention to abnormal features, and because of an enormous amount of information collected. The information is color-coded, so a normal activity might be an earth-color, and to some excess region, that region is red- the more abnormal, the brighter the color of red, all the way up to orange. If there is something lacking in an anatomical region, if it is deficient in an activity, that region is blue, and abnormalities appear as blotches of colors in certain regions, and so we have patterns identifying major psychiatric disorders, such as alcoholism, schizophrenia, etc. It's a functional analysis. It reveals abnormal transactions between brain regions. Those brain regions may interact abnormally for several reasons, maybe abnormal structures, two is in spite of normal structure, their neurochemical reactions are abnormal, which we also see. Even with normal neurochemical capability, and normal anatomical structure, the brain can enter certain states which are abnormal, for example, we had a patient come in for examination who was a staff member here at the university, who was known to the technician performing the examination. The results were perfectly normal. After completion of the examination, the technician who knew the volunteer, asked her a personal question about her boyfriend, and in fact this person had a very disruption of the relationship with the boyfriend, and while she reacted to the question, accidentally, the recording continued, and that recording was analyzed and showed pathological depression. Here we had in a couple of minutes a brain moving from nondepression to depression to nondepression. That was not abnormal chemical ability, that was just a state, and what we can see is the change of states as people think of different things as they have different moods, and those two reflect abnoramlities and transience ... some therapists work with people that have pathophysiological resistance to psychotherapeutic treatment. With neurometric evaluation, it is possible to intervene more effectively. Psychology has dealt with the organism as a black box for a long time, with these inferences people can learn a lot about what's inbetween, and we're now opening the box."

While some neuroscientists explore the electrical activity of the brain, others are studying chemical activity. Drug+brain research. The brain is a biochemical drug factory that manufactures opiate-like molecules. These molecules are called opiopeptides, that are part of neurotransmitters that send messages from cell to cell. There are many types of endorphins- which also come in corresponding opiod receptors. There is a finely tuned division of behavior between these. The action of each of these molecules is mediated by different types of receptors. Endorphins, like narcotics, can reduce pain, create euphoria in runners, etc. In fact, they play a major role in most experiences involving pleasure or pain. Research has shown them in a host of emotional actions, like laughing, crying, arousal, etc.

University of California, Berkley, Joseph Martinez, has been investigating how brain chemicals affect learning. "We find neurotransmitters, and we think some are important for learning, and by knowing what these chemicals are, we are able to mimic how the brain talks to itself, and we can coax the brain into forgetting an experience, or make it actually remembering better by stimulating some of these chemical systems. In our experiments, we use very simple learning situations. ... Even though we have trained them in this maze-task, the paths are not fixed in long-term memory. And since it takes a period of time, we can interfere with the animals and inject them with a drug called Psothaolomine (sotholomine?) which blocks the transmission of information, and the others receive saline. They do not receive drugs while learning. After training, we inject them with the drug, and we found that this is a form of experimental amnesia. This is a synapse that contains the neurotransmitter acetylcholine. Scuopotomaine, blocks acetylcholine, and this leads to experimental amnesia, and we can do the opposite by stimulating the synapse, which is physostuggunne, which braeaks down acetylcholine ... acetylcholine is a neurotransmitter that is tremendously reduced in Alzhtimer's disease."

If brain imaging, experimental drugs, and EEG recordings can help us improve our understanding of the brain, can damaged brains be rejuvenated? Fred Gauge, is a psychologist-neurologist, has had research that goes towards ways to overcome brain damage. "In a situation where the cells die and disappear, we use neuronal transplantation- we take prenatal cells and put them into the area of the brain where the cell death has occured. This is substitution. There are several examples where this methodology has shown that graphted cells can become functional. One example has been done with aged rats. There is a subpopulation of aged rats with severe memory deficiet, which is exmpleified with a clever test - when animals have to find a platform hidden in a large pool, so they use clues mounted all outside around the pool, and the animals will be able to locate these platforms, but a subpopulation of the rats never learn to use the clues to find the hidden platform. What we did, then, is use cells from the basal forebrain, into the neocortical areas of the brain, and after three months of observation, we found that the animals were able to learn the task in the ways that they were not able to do. One disease that we do know something about is Parkin's Disease. This is a disease where specific neurons, called dopamine neurons, die and disappear. An animal model for Parkin's has been developed, where one side of the brain has been depleted of its dopamine. Transplating prenatal cells to the depleted side has been shown to be successful. These cells actively secrete dopamine from their synapses. This model has been the foundation for the recent clinical trials that have been undertaken in severeal countries. At present, we don't know the results in humans, but it's an area of great excitement, which will have implications for the utility of neural graphing."

Some might argue, as we understand the biochemical basis, we will lose the mystery and wonder of the brain. The more we know, the more we marvel. It takes only 3 pounds of matter to make a human mind, and yet it is designed to do more than supercomputers hundreds of time their size. Some combination of molecules flowing between cells, is somehow the foundation of our abilities, memories, feelings, dreams.

In our next program, we will explore something equally remarkable: how the brain is changed by the world around it, how it responds to new challenges, by continually modifying itself. The responsive brain.

The Responsive Brain

The brain is an organ of passion, of pain, of creativity. The relationship between brain and behavior is reciprocal, because the brain controls behavior, but the behavior feeds back information to influence the brain. In this sense, we can talk about the responsive brain, as well as the behaving brain. The brain is constantly open to change, it can alter its own functionality and structure, as it learns more and becomes more knowledgable and sophisticated about the world around it. This capacity for internal modification makes it a dynamic system.

How does this two-way process work? Let's use touch as an example. Touch is a silent language that people communicate in. Personal contact is governed by unspoken cultural rules and regulations. In our culture, men and women touch for different reasons. In one study, nurses touching women had reduced blood pressure during the operation. Researchers find that, regardless of gender, those that are more comfortable with people touching them, they are less suspicous of other people's motives. Those uncomfortable are usually more socially withdrawn. Touch-depravation has significant outcomes.

The brain apparently creates a need for touch?? When premature babies are put into care systems, they lack one thing: human touch. What difference would it make if some of the infants are given daily touch sessions within incubators? Tiffany Field asked this question. 20 premature infants were randomly selected to get massages, while others got the usual hospital treatment without the treatment. The care they received was otherwise identical. Premature babies who are massaged for 45 minutes, for 10 days, before they were discharged, gain 47% more weight than the babies who did not get massaged, and they were more active, more alert. At 8 months, they are still showing good cognitive development, and better motive development. The babies fair better, and so does society. Sending premature infants home early could save millions of dollars per year.

At the same time, Saul Shamberg of Duke University, lead another research team. He showed how mother's touch has real biological value to its offspring. "A mother's touch, we know now, .. to maintain normal growth and development .. and what we found was that when rat babies were removed from the mother for even a short period of time, this enzyme (ODC) went way down which is bad for growth/development, so we were faced with a situation where we were trying to understand how it was that a short term separation could have such dramatic effects throughout the body on the actual process of growth. We have found that the depravation effects that we see, to be reversed by only returning it to the mother, who goes through the process, or by the technician and stroking the pups with a certain frequency and strength that is a pattern of touch that we have discovered." Cindy Coon- deemonstrates how the infant rats are treated. Normal active maternal behavior, she has been dsiturbed of her nest, so she is ..." <--- funny. Anyway.

"What we have here are pups who have been away from the mother for about 2 hours and have had a temporary depravation of touch, and with this brush, we think this stimulates how she behaves when she licks them and retrieves them and so on. We have found that the longer they are way, we have found greater depravation symptoms. Tjos retirms tjeor ynyxts yd moys;. It is required for growth." Is lack of affection what stunts the growth of children? "Yes." Institutionalized youngesters who are emotionally deprived, their rate of growth was significantly below their normal range for their age groups. Psychosocial dwarfism- emotional depravation stunts physical growth due to the hypothalamus which normally stimulates the pituitary gland. The lack of touching may have the same effect with the rats, reducing the production of biochemicals essential for growth. But whenever children are with loving families, they begin to return to their normal signs. In one study, when children were returned, they shot up their rates and so on.

What about permenent alterations of brain structure? University of California at Berkley, Mark Rossinbaum- rich, stimulating environment for rats. Not only were the enriched rats better performers, their brains grew larger, and their opcitical cortex (vision) was bigger. There was a greater number of certain neurotransmitters, and more dendrites that were branching out, and these sorts of physical changes in the brain can have a life-long effect. Studies have shown, for instance, that touching newborn rats, not only stimulates growth, but helps them cope better with stress throughout their life, and this reduces learning disabilities and diseases of senility. Michael Mead is investigating how early experiences can change brain, and how stress causes glucocortoids releases.

"When you expose an organism to stressful situations, digestion is decreased, and the organism is better able to deal with the challenge. The problem with the extensive exposure to stress, is that glucocortoids can build up and damage the hippocampus, essential for memory and learning, the problem with this is that neurons die and the brain is less able to process information. When you handle the young animals, it makes the animals more capable of turning off the stress response. The animals that are not handled, are less capable of handling the stress response, and when you examine the animals later in life, the nonhandeled animals have learning impairments. We are trying to examine the ability of animals to learn and remember (spatial) events. Rats will use the first opportunity to get out of water when put into a tub. The animals are able to quickly learn where the platform is located, but when you look at the older nonhandeled animals, they take a long time and poor memory to get it all working. This machine measures position and distances of the swimming rat. Beep beep beep."

"So, in the individuals showing intellectual impairments, these people might be like less handeled rats, and so this means they may have increased glutocorticoid levels, and hippocampal damage." (See "You shall not fold your wings.")

Perhaps the clearest example of brain altered structure, in response to social situations, is perhaps in evolutionary scenarios. Charles Darwin made us aware of "survival of the fit." Elk. Individual survivability does not matter as much as special survivability. (WTF). For example, birds that sound an alarm when predators are near, this is an essential survival skill for the rest of the group. This requires a major reorganization of brain structure and physiology. Russel Frnoald, from the INstitute of Neuroscience at Oregon (maybe), is a neuroethologist.

"I have been interested for a long time about how behavior modifies the brain. What about the African Sickly Fish? It is one of many species that relies on visual signals to communicate with one another. The social system is based upon territories." Terrotorial dominance of males, and when bullied he can turn this all off, and as a consequence his testes will regress, and in some instances, the brain area will reduce in size, and the territoriality is reversible. In the brain is a specialized nucleus which reflects the social success (what?).