Sunday, December 30, 2007

And it's about brain parts: like Hippocampus

In reference to It's all about movement:

From our PT perspective it's might be about movement, Matthias, freedom from pain, but I would propose that from a functional perspective there are other considerations, such as having good working brain parts, understanding their contributions to movement, to pain processing, or purpose having us move from A to B in the first place.

The hippocampus has been a riveting study focus for me this fall and winter. Buzsáki has worked for decades to understand brain waves, and noticed that theta waves, his favorite, seem to come from there. My impression from reading his book is that theta waves are like a drum beat setting a rhythm for all the other kinds of waves.

If I may, further to the discussion about types of memory, Learning to Memory, I want to post a link to a fascinating lecture video, a 2005 talk by Sue Becker from McMaster called The Role of the Hippocampus in Memory, Contextual Gating, Stress and Depression. It touches on Hebbian learning, neurogenesis, topics we took a look at in History of Neuroplasticity. Becker is building on this to examine what the learning rules might be, and build models for them. She describes the hippocampus as a large convergence zone, where information from lots of other parts is "coded". Neurogenesis takes place here. A constant supply of new neurons seem to be necessary for coding memories over time, over temporal gaps. If neurogenesis is slowed by stress, new connections have trouble being made. (Sapolosky has mentioned this as well.) New neurons remain plastic (able to make new connections) for longer than old ones.

Single cell recordings of spatial coding cells in the hippocampus have been made with human subjects, as they move about in a virtual world (prior to this only rats had been examined). She touches on spatial hemi-neglect, neglect of the left half of a person's environment following a type of stroke; she is working on building a model that can account for both "egocentric" (sensory/self) and "allocentric" (other/outside) spatial coding.

Her third area of investigation is the role the hippocampus as a comparer and coder of personal behavior. This brings in the role of context. The hippocampus is crucial for determining context of a situation, and allow you to react appropriately in a stressful condition. Here we come back to producing movement again. If the hippocampus isn't working, how will you know what movement to choose? The hippocampus may exert a modulatory effect on other parts of the brain.

Also, here is a link to one of Ginger Campbell's brain science podcasts (Episode #3) which discusses Eric Kandel's book, In Search of Memory. In episode #12 she discussed another book, Memory: From Mind to Molecules, by Larry Squire and Eric Kandel.

The internet is absolutely full of great information.

1 comment:

Adeline said...

Wonderful message. I like his post. I have read the article you mentioned it looks very interesting. Now i came to about brain parts.
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