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 longterm 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 threads of the spider’s web have broken because of lack of interest and disuse.
Over time, long-term memory tends to get pushed from consciousness into the subconscious. Then a simple cue, an odd association, a chance meeting, can activate the sleeping spider’s web and fire the neuronal circuits, resurrecting the long-term memory that had seemingly evaporated from your mind.
Taken From: The Memory Program How to Prevent Memory Loss
and Enhance Memory Power
