Explicit Memory: Description And Function

Theories of memory divide it into two categories: Implicit memory (or reflective), related to learning abilities, and explicit memory. Implicit memory is when you store procedures such as driving, cycling, or doing routine tasks on your computer.

Explicit memory (or declarative) in turn, stores memories that can be awakened consciously. Explicit memory is also divided into two categories: episodic memory and semantic memory.

Episodic memory

Episodic memory stores memories related to personal events. Thus, it helps you remember the wonderful trip or afternoons of childhood where you played with friends in the park. It also lets you talk about these memories.

This information is located in time and space, which is why the contextual environment of memory is so strong. Furthermore, the reference point for the memories is the person himself. Thus, the reason we remember certain things at certain times is usually due to the surroundings around us. For example, returning to a place where something happened in the past can trigger certain memories.

Due to this strong connection to context, episodic memories are easier to forget or distort. Therefore, people often have problems with autobiographical details, and often confuse time or place with events in their own lives.

This happens especially when someone asks you to provide details about an event or a memory, as in the case of witnesses. The expectations that the person has and your desire to be happy can actually change your memory.

Explicit memory: Brain structures involved in episodic memory

The temporal lobes, where the hippocampus is located, are responsible for the creation of new episodic memories. The front panel also seems very important for spatial and temporal coding of the memory. In other words, it helps you with where and when you had the experience. This allows you to organize your memories better.

Disorders of episodic memory

The biggest disorder that affects episodic memory is Alzheimer’s. Memory loss of these memories occurs in the first phase because the hippocampus is one of the first structures to be affected by this disease. Episodic memory loss is also common in food poisoning from seafood. Strange as it may sound, food poisoning from seafood can actually lead to irreparable damage. The same applies to Korsakoff’s psychosis.

Stress and the use of drugs such as ecstasy and MDMA can also damage the episodic memory.

Explicit memory: Semantic memories

These types of memories contain knowledge of language and the world around us. It’s like an encyclopedia or dictionary. This type of memory allows you to remember the meaning of words and, for example, the relationship between two ideas.

Although this type of knowledge can be linked to episodic memory, it is usually generic and decontextualized. This makes it easier to remember. An example of a semantic memory is whether you learned the meaning of Rue de Rivoli when you visited the Louvre last summer.

The brain structures involved in semantic memory

Some authors claim that episodic memory and semantic memory involve the same brain structures. But there are studies that find no relationship between the hippocampus and semantic memory.

Some authors relate it to the neocortex and others claim that the structures involved depend on the knowledge you are trying to remember. For example, knowledge related to the sound of a tin can falling to the ground will activate the auditory cortex. Remembering the color of a specific animal will activate the visual cerebral cortex. The temporal lobes are also involved in the integration of all semantic information.

Disorders of semantic memory

Semantic dementia is a neurodegenerative disease that affects the temporal lobe. This disease can affect the ability to name objects as well as access their meaning. Individuals suffering from semantic dementia gradually lose the ability to categorize concepts in a detailed way. For example, it interferes with their ability to use familiar words or visually recognize objects.

In general, Alzheimer’s can also cause disorders in specific categories, as Alzheimer’s patients also have difficulty naming or describing objects.