What Is Memory: Improving Memory Understanding Age Related Memory Loss

Content provided by the Faculty of the Harvard Medical School

What is memory?

Memory is all that you remember as well as your capacity for remembering. Not all memories are created equal. Some memories are meant to be retained for a short period and then discarded. For example, you remember the telephone number of the local pizza place only long enough to dial it. But memories that are more important are stored in the brain and can be retrieved at will: the names of close friends and relatives, the multiplication tables, your phone number, and other information you use regularly. Certain kinds of information can be memorized only if you concentrate, whereas other kinds of memories, such as the faces of people you see regularly and the steps of simple everyday routines like brushing your teeth, are absorbed without conscious effort. The process of learning new information, storing it, and recalling it involves a complex interplay of brain functions (see Figure 1).

Figure 1: Anatomy of a memory Deep within the brain, a primitive structure, known as the hippocampus, plays a crucial role in acquiring and consolidating new memories. The nearby amygdala is the part of the brain that reacts to emotionally powerful information, helping the brain retain information that has emotional impact. Once a memory is established (consolidated), it is stored mainly in areas of the cerebral cortex, the large, domed outer layer of the brain.

But what are memories themselves? Let's start by looking at the nature of memories, their surprising intricacy, and the reason some memories endure while others fade away.

Researchers and neuroscientists have devised several classification systems to capture the various forms of memory. One major system relies on time, making a distinction between short-term memories, which are fleeting, and long-term memories, which can persist for a lifetime. Another scheme breaks memories down according to the type of information they contain, such as whether they are straight facts or the procedures for doing something.

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Last updated:	January 23, 2007