Electrical Activity, Chemical Activity, Connectivity, and Epigenetic Activity

All of these are involved in making our memories. Our short term or working memories are held in fleeting changes in the brain‘s electrical and chemical activity. They quickly fade as our attention wanders, but they provide the basis of our conscious awareness.

Our long term memories are woven into webs of connections among the brain cells. The brain alters the communication between networks of cells by the creation of new receptors at the end of a neuron, by a surge in the production of a neurotransmitter, or by the forging of new ion channels that allows a brain cell to boost the voltage of its signals. The same pattern of neurons will fire when we recall the memory bringing the thought back into our consciousness. Long term memories include our autobiographical memories, our episodic memories of specific events in our lives, our sensory memories, as well as our semantic memories that comprise our knowledge of the world. One of the most important brain regions involved in this process are the hippocampi. The are located near the base of the brain and are especially important in the consolidation of new memories. When they are surgically removed or damaged, no new memories can be stored. Thus, no new learning can take place.

The preceding has been known for some time, what is new is an understanding of the epigenetic changes that are involved in memory. These involve small alterations in the structure of a gene and determine its activity within the cell. For instance, certain genes linked to the formation of memories have been shown to have fewer methyl groups attached to their DNA after learning. This is a clear example of an epigenetic change.1 Every time we recall a memory, new proteins are made. The epigenetic markers are altered changing the memory in subtle ways. So the brain is not like a video camera. It is dynamic and changes itself.

1Young, E. (2012). The Making of a Memory, New Scientist, 6 October, p.34.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

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