By Richard Restak, M.D., The George Washington University School of Medicine and Health Sciences

Edited by Kate Findley, The Great Courses Daily

We sometimes refer to memory as “photographic,” and indeed, photos can capture potent memories. Digital cameras make it possible to date stamp each picture. Depending on privacy settings, GPS location settings can get an exact fix on where someone was when the picture was taken. As Dr. Restak explains, though, memory is too important to delegate to our technological tools.

Brain Memory and Computer Memory

Is the brain like a computer? Indeed, the two have many similar features, and a computer even has “memory.” However, the type of memory found in our brain is much different than computer memory.

“The art of remembering is the art of thinking,” said William James, one of the foremost psychologists of the 19^th and early 20^th centuries. Memory also involves chemical and structural changes. 

Consider the Nobel Prize winning psychiatrist and neuroscientist Eric Kandel’s work on Aplysia, or the so-called sea slug. When the gill is touched, or poked, the gill tends to retract. The more it is poked, the more this particular reflex occurs. 

Thus, repetition of occurrences favors memory consolidation. This is true for human beings, too. As the concentration of neurotransmitters in the human brain changes, neurons grow, then forming synaptic terminals. Human brains undergo both biochemical and anatomical changes. As new proteins produce these changes, new connections are made, called synapses. 

If the repetition of the experience decreases, the number of synapses also decreases. Therefore, there’s a relationship between the stimulation, the chemistry, and the anatomy.

The bottom line is that synapses are not fixed; they change with learning, thus, demonstrating our brain’s plasticity. Memory encoding also involves molecular changes within the neurons. 

Memory Formation

Short-term memories involve more than simply the transmission between one neuron and another. A particular neurotransmitter called glutamate is altered, and there are also interneurons that produce serotonin, which sort of tune the release of the neurotransmitter glutamate. 

This fine-tuning occurs through a series of cascading molecular signals that eventually lead to modification of the cell nucleus of the neuron. You’re changing the genetics of the neuron through these experiences—an example of epigenetics. If the changes delve right into the neuron, they will transform the whole structure of the neuron in terms of its biology and biological destiny.

Memories are thus the result of an elaborate process involving chemical and genetic signals that result in new synaptic terminals. Eric Kandel said, “Short-term memory produces changes in the function of the synapse, strengthening or weakening pre-existing conditions; long-term memory requires anatomical changes.” 

Memory and Emotion

Unlike computer memory, the brain is always in a state of renewal. Memory is also influenced by emotions, and different memories are infused with different emotions depending on the situation. 

If someone asked you to remember September 11, it’s not just a date; it’s a specific event which occurred on September 11, 2001. If you’re old enough, try to remember where you were and what you were doing when you heard about the death of JFK—President John Fitzgerald Kennedy. 

Recalling a memory restarts the process of consolidation; it involves emotions as well. It begins as a short-term memory, and then new proteins are produced for consolidation to long-term memory. 

Therefore, remembering is a creative act that can’t be duplicated by a computer. Joseph LeDoux, a neuroscientist who’s done a lot of research on memory, said, “The brain that does the remembering is not the brain that formed the initial memory. In order for the old memory to make sense in the current brain, the memory has to be updated.” 

Thus, as time goes on, changes to your personality occur in tandem with changes to your memories. This process has important implications for our understanding of memory. 

The Greek philosopher Heraclitus said you can’t enter the same river twice, meaning it’s always changing. You also can’t remember the same experience exactly alike on different occasions. The you of right now is different from the you who was present a short while ago, or who remembered and earlier consolidated a memory. 

This article was edited by Kate Findley, Writer for The Great Courses Daily.

Dr. Richard Restak is Clinical Professor of Neurology at The George Washington University School of Medicine and Health Sciences. He earned his M.D. from Georgetown University School of Medicine. Professor Restak also maintains an active private practice in neurology and neuropsychiatry in Washington, D.C.