Page 42 - The Memory Program How to Prevent Memory Loss and Enhance Memory Power

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Hippocampus: Grand Central Station of Memory

The hippocampus is a wing-shaped, inch-long structure that makes up the inner part of the temporal
lobe. The temporal lobe is a bigger structure, the size of a large kiwi fruit or oblong plum, that
projects from the lower front part of the brain and lies just beneath the side, or temple, of the
forehead. The brain is divided into two big halves, so the right hippocampus is part of the right
temporal lobe, and the left hippocampus is part of the left temporal lobe.

Nerve impulses from our senses first pass through a filter that screens the information and ignores
what is unimportant. If the information survives this first gauntlet, it is sent via nerve cells to the
hippocampus and surrounding regions. Each specialized neuron in the hippocampus records an
element of the fact or event, and these nerve cells link all the components together to form a
composite memory trace. This memory trace is housed in thousands of nerve cells, probably in
proteins and ribonucleic acids (RNA).

How Short-Term Converts to Long-Term Memory

If the memory is important enough, or if the same event repeats many times over a long period, the
short-term memory trace residing within these hippocampal nerve cells is eventually moved into
permanent, long-term storage. The hippocampus has broad-band connections— fiber optic rather than
regular copper wire— to the frontal lobes, where many long-term memories are stored (some long-
term memories remain in the hippocampus).

The Web of Memory

Each memory is a complex web of material that mixes facts, sensations, and emotions. When a
strong emotion accompanies an event, you release more of the chemical transmitters that
communicate among nerve cells to help form memories. Emotional states represent an important
“internal’’ environmental cue for memory. Think of the emotion-laden memories that flooded
through your mind at your graduation, your wedding, when you had major conflicts with family
members, or when you lost someone close to you. These memories stay hardwired forever in your
brain, ready to be recalled whenever the occasion arises. On the other hand, you remember only
fragments of less important and less emotional events, such as the details of a boring business trip or
meeting; the