Daniel Nation, PhD
Daniel Nation, PhD, is an expert in neuroscience and brain aging and professor of gerontology and medicine at University of Southern California in Los Angeles. USC.edu
Anytime you get dressed, sing along to a favorite song, drive a car or walk along a crowded street, you’re tapping into your implicit memory. That’s the term psychologists use to describe the way information stored in the brain can be recalled and put to use without any conscious effort. Implicit memory—also called procedural or nondeclarative memory—makes it possible to engage in daily tasks and activities more or less automatically.
Implicit memory differs from another type of long-term memory known as explicit, or declarative, memory, in which conscious effort is required to recall facts, dates, events and the like. Bottom Line Personal asked neuroscience and brain-aging specialist Daniel Nation, PhD, to explain how these two types of memory work.
Implicit and explicit memories are stored and processed in different regions of the brain.
Explicit memories reside in the cerebral cortex—the brain’s wrinkly outer layer that contains a network of tightly folded brain cells, or neurons. That’s where most higher brain functions take place, including consciousness, reasoning and decision-making.
Implicit memories lie mostly within the brain’s subcortical regions, below the cerebral cortex, and span several neural structures, including the striatum, thalamus, cerebellum and basal ganglia. In evolutionary terms, the subcortical structures are much older than the cerebral cortex.
Subcortical structures often remain relatively intact even in people with advanced Alzheimer’s disease. These people sometimes retain the ability to perform basic tasks and participate in daily activities despite their cognitive deficits. Some famous entertainers stricken with dementia, including musician Glenn Campbell, continued to sing and play musical instruments even in advanced stages of the disease.
Both implicit and explicit memories are distinct from short-term memory, in which small bits of information are stored for only a matter of seconds or minutes.
Eating healthfully, exercising regularly and getting plenty of sleep can help ensure that you are able to create, preserve and recall memories. Repetition is another key ingredient for forming strong memories, whether it’s reciting a speech several times to learn the words by heart or driving repeatedly to a particular destination so you can navigate without the help of a map or a set of directions.
