Long-term Memory - Types of Memory

Types of Memory

The brain does not store memories in one unified structure, as might be seen in a computer's hard disk drive. Instead, different types of memory are stored in different regions of the brain. LTM is typically divided up into two major headings: declarative memory and implicit memory (or procedural memory). Computer programs store information similarly, with a separate data section and code section.

1. Explicit memory/Declarative memory refers to all memories that are consciously available. These are encoded by the hippocampus, entorhinal cortex, and perirhinal cortex, but consolidated and stored elsewhere. The precise location of storage is unknown, but the temporal cortex has been proposed as a likely candidate. Declarative memory also has two major subdivisions:
   • Episodic memory refers to memory for specific events in time, as well as supporting their formation and retrieval. Some examples of episodic memory would be remembering a name and what happened at your last interaction with each other.. Experiments conducted by Spaniol and colleagues has indicated that older adults have worse episodic memories than younger adults because episodic memory requires context memory.
   • Semantic memory refers to knowledge about factual information, such as the meaning of words. Semantic memory is independent information.. In contrast with episodic memory older adults and younger adults do not show much of a difference with semantic memory, presumably because semantic memory does not depend on context memory.
2. Implicit memory/Procedural memory refers to the use of objects or movements of the body, such as how exactly to use a pencil, drive a car, or ride a bicycle. This type of memory is encoded and it is presumed stored by the cerebellum and the striatum. The basal ganglia is believed to mediate procedural memory and other brain structures and is largely independent of the hippocampus.Procedural memory is considered non-declarative memory or unconcious memory which includes priming and non-associative learning..

There are various other categorizations of memory and types of memory that have captured research interest. Prospective memory (its complement: retrospective memory) is an example.

Emotional memory, the memory for events that evoke a particularly strong emotion, is another. Emotion and memory is a domain that can involve both declarative and procedural memory processes. Emotional memories are consciously available, but elicit a powerful, unconscious physiological reaction. They also have a unique physiological pathway that involves strong connections from the amygdala into the prefrontal cortex, but much weaker connections running back from the prefrontal cortex to the amygdala.

Working memory is not part of long term memory, but is important for long term memory to work. Working memory holds and manipulates information for a short period of time, before it is either forgotten or encoded into long term memory. Then in order to remember something from long term memory it must be brought back into working memory. If working memory is overloaded it can affect the encoding of long term memory. If one has a good working memory they may have a better long term memory encoding.