Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance by Richard Restak Page B
Authors: Richard Restak
Tags: nonfiction
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patient (identified as H.M. in order to protect his privacy) lost his capacity to form new memories following a brain operation that removed the hippocampus and parts of his anterior temporal lobe on each side of his brain. As a result of his absent hippocampi (the plural form; there is one hippocampus on each side of the brain), H.M. permanently lost the ability to form new memories. Each time he encountered his doctor the experience was a new one for him. His memory was so bad that after learning of his mother’s death, he soon forgot this distressing information, and over the years he became upset and wept anew whenever anyone mentioned that she was no longer alive.
Despite its tiny size, the hippocampus is one of the most powerful structures of the human brain. Everything you ever learn wends its way through this portal prior to its distribution throughout the remainder of the brain. If your hippocampus is damaged as a result of a stroke or traumatic brain injury, you can no longer establish new memories, as happened with H.M. A similar but less severe failure occurs with depression. As part of the depressive experience, the hippocampus atrophies and memory failures become commonplace, often leading to an incorrect diagnosis of dementia. But whatever the cause, impairment of the hippocampus causes newly learned information to drift off a person’s mental horizon after only a few moments. What’s worse, this drift into mental oblivion can’t be prevented despite a person’s best efforts.
In my office I routinely test hippocampal function in those patients I suspect may be suffering from damage in that area. I ask them to learn and retain five simple words, such as apple, tie, pen, house, and car. Even severely affected patients can initially repeat the words back after a few attempts. The problem arises when I ask them to repeat the words again after a five-minute delay; those with hippocampal failure can’t remember more than one or, at best, two of the words. Persons with normally functioning hippocampi, in contrast, can usually manage to come up with all five of the words. People with damage to the hippocampus perform so poorly because their brain can’t encode the test words—a prerequisite for holding them in short-term storage.
According to recent research, both the recollection of past events and the imagining of future ones require a normally functioning hippocampus. For instance, one fMRI study of healthy volunteers revealed that recalling past experiences and imagining future experiences activates a similar network of brain regions, including the hippocampus. As further proof of a memory-imagination link, people with faulty memories secondary to dysfunctional hippocampi have difficulty imagining anything that hasn’t actually happened. For example, those with hippocampus-related memory problems do poorly when imagining a meeting with a friend on a specific street corner or dining with a friend in a familiar restaurant. It’s as if both the imagined and the recollected world are rendered in shades of gray instead of vivid color.
This new discovery of a link between memory and imagination was anticipated in Greek mythology where Mnemosyne, the goddess of memory, gives birth to the muses, a sisterhood of spirits who inspire the creative process through remembrances. It also suggests a strategy: the use of memory exercises as a means to foster imagination and vice versa. Creative-writing teachers have always had an intuitive feeling for this approach. They encourage their students to provide from memory highly specific details about the places and people they have known. This enables the writer to create in his or her imagination more memorable scenes and characters. Using this technique, the author can render his fictional creations with greater believability since they’re based on real people and places that he remembers from previous encounters. In order to provide remembered details about real
Despite its tiny size, the hippocampus is one of the most powerful structures of the human brain. Everything you ever learn wends its way through this portal prior to its distribution throughout the remainder of the brain. If your hippocampus is damaged as a result of a stroke or traumatic brain injury, you can no longer establish new memories, as happened with H.M. A similar but less severe failure occurs with depression. As part of the depressive experience, the hippocampus atrophies and memory failures become commonplace, often leading to an incorrect diagnosis of dementia. But whatever the cause, impairment of the hippocampus causes newly learned information to drift off a person’s mental horizon after only a few moments. What’s worse, this drift into mental oblivion can’t be prevented despite a person’s best efforts.
In my office I routinely test hippocampal function in those patients I suspect may be suffering from damage in that area. I ask them to learn and retain five simple words, such as apple, tie, pen, house, and car. Even severely affected patients can initially repeat the words back after a few attempts. The problem arises when I ask them to repeat the words again after a five-minute delay; those with hippocampal failure can’t remember more than one or, at best, two of the words. Persons with normally functioning hippocampi, in contrast, can usually manage to come up with all five of the words. People with damage to the hippocampus perform so poorly because their brain can’t encode the test words—a prerequisite for holding them in short-term storage.
According to recent research, both the recollection of past events and the imagining of future ones require a normally functioning hippocampus. For instance, one fMRI study of healthy volunteers revealed that recalling past experiences and imagining future experiences activates a similar network of brain regions, including the hippocampus. As further proof of a memory-imagination link, people with faulty memories secondary to dysfunctional hippocampi have difficulty imagining anything that hasn’t actually happened. For example, those with hippocampus-related memory problems do poorly when imagining a meeting with a friend on a specific street corner or dining with a friend in a familiar restaurant. It’s as if both the imagined and the recollected world are rendered in shades of gray instead of vivid color.
This new discovery of a link between memory and imagination was anticipated in Greek mythology where Mnemosyne, the goddess of memory, gives birth to the muses, a sisterhood of spirits who inspire the creative process through remembrances. It also suggests a strategy: the use of memory exercises as a means to foster imagination and vice versa. Creative-writing teachers have always had an intuitive feeling for this approach. They encourage their students to provide from memory highly specific details about the places and people they have known. This enables the writer to create in his or her imagination more memorable scenes and characters. Using this technique, the author can render his fictional creations with greater believability since they’re based on real people and places that he remembers from previous encounters. In order to provide remembered details about real
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