Saturday, November 8, 2008

Physics and the brain

**Meandering-Entry Alert**
This entry talks about replacing depressed thoughts and associations with pleasant ones, creating new associations and memories in the brain that can be the basis for a more pleasant life. It builds off of brain theory (neural networks from a lecture from U. of Mich.) and psychotherapy.

Self Sabotage
My husband, Peter, a psychotherapist, has written a book on self-sabotaging behavior. He says that we subconsciously try to repeat negative experiences - usually left over from earlier times or childhood. It is hard to change our ways. For example, if we are depressed, we will seek out behaviors to reinforce our depression. He says that we have to catch ourselves in the act, and then purposefully change what we do.

The Novelty of Pleasant Associations
I would like to propose that when we feel depression stir, we step back from it, see it for an emotion (that is, don't identify with it, just look at it) for about 10 seconds. It will fade. When it comes back (even in a few seconds), repeat the process. At this point, we should be in a less-depressed state. Now try to find gladness, and look for things to associate it with: a potted plant, art, a person we enjoy. This new memory is novel. It will be taken into the brain, and if it sits there for a few minutes without depression, may stick. Thus we will have associated something in our environment (the plant) with gladness, and with repeated sessions over several days, can take hold in our being.

This method creates a novel experience, a novel association between pleasantness and situations that might have been associated with depression. For example, Michigan is gray in the winter. Without sun, people here tend to get seasonal affective disorder (and the poor economy is no help!). So, what happens, for example, if you go away from Michigan for 5 years? A psychiatrist friend of mine once explained that without the associations of winter events with no sun, seasonal depression will fade. In place of gray skies, different memories will exist and they will override the gloomy ones.

Can one get the sad memories to fade without leaving the gloomy weather? I think so. Read on.

Lecure on Memory
The beauty of living in a (great) college town is the availability of stimulating lectures. Today, Professor Michal Zochowski of the University of Michigan Biophysics department lectured on "Physics and Brain Function". Professor Zochowski creates neural networks in petri dishes. A neural network is a very complex structure that can be "taught" to learn things. That is, information can be input to the network and then retrieved later. The format of the neural network's information is so complex, that you can't figure out what it is doing. For example, if I look on my computer for information I have stored, I can find it. I can see the folders and find the folder it is stored in, open a file in the folder and then find the informaiton. However, this is not possible for information stored in a neural network.

If you try compare the brain's memory and function to a (PC or Mac) computer, the comparison breaks down very quickly. Computers are far to simplistic. However, it is possible (at this point), to use a neural network to model brain function and gain some insight.

Professor Zochowski uses his neural networks to simulate the brain's hippocampus and cortex. The hippocampus is thought of as a "device" that 1) finds interesting (and novel) associated bits of information and 2) keeps alive a memory of the bits and their association so that the cortex can (very slowly) put this into long term memory as a newly learned fact. The cortex acts as a mechanism for creating and storing long-term memories. Together, they take novel information, keep an impression of it alive and then after a while (if the information is interesting enough to be still alive), store it in long term memory and create rich connections so that it is easily found. To test these assumptions of how the brain's memory works, Professor Zochowski programmed his neural networks to mimmick the hippocampus and cortex as stated above. The model duplicated know brain wave formation and function, and so the neural network is a good model for now.

Back to Michigan gloom, memories and making new associations. What does the neural network experiment tell us? Does it support our thesis of replacing sad memories with happier ones? I think so.

The model suggests that by creating a new set of associations and holding them steady for a few minutes, a new memory is made. We need to pay keen attention to the stimulus (the pleasant association) so that it appears to be a novel event. If it is done repeatedly, it will strenghthen and override the old one. With disuse, one hopes that the old memory will fade.

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