memory

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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Memory is the ability to remember things, people and events. Memory is the prerequisite for any behavior that controls present and future behavior based on experience of previous impressions and experiences. Read everything you need to know about different types of memory (short and long-term memory, declarative memory, etc.) and memory disorders!

What is the memory?

Memory can be understood either as a process or as a structure with the help of which people can store information and retrieve it later. The memory is divided into several different categories, which relate to the time span in which the memory contents can be retrieved.

Ultra-short term memory

Immediate memory ("immediately" = immediately) is often referred to as ultra-short-term memory or sensory memory. Its contents are only retained for a few milliseconds to a maximum of two seconds. This is the shortest period of time in which facts and sensory impressions remain present. It is just sufficient to enable initial information processing. For example, a new telephone number ends up in ultra-short-term memory (or sensory memory), which you can hear and then enter into the telephone.

Newly arriving information quickly displaces the current content in the immediate memory. Only a small part of the information is transferred from sensory memory to short-term memory.

Short term memory

The short-term memory enables data to be saved over a period of a few seconds to a few minutes. For example, you can briefly remember a number you have looked up until you have written it down.

In the first phase after memory content has been recorded in the short-term memory, it is not yet stored in a stable manner. For example, a concussion in an accident can cause a memory gap that goes back seconds and up to several hours before the event.

Long-term memory

The long-term memory contains all the important information that is worth keeping and that would otherwise cause the short-term memory to "overflow". This type of memory is what is generally meant when we speak of memory.

The extent of long-term memory varies greatly from person to person - it not only includes the active and passive vocabulary of our mother tongue, but also all memories, data, facts, learned knowledge and the vocabulary acquired in foreign languages. Long-term memory stores everything that should be kept in the long term due to multiple repetitions or with a strong emotional content.

Long-term memory is divided into declarative and non-declarative memory:

As declarative memory (explicit memory), medical professionals refer to the part that stores explicit, i.e. conscious, linguistically retrievable content. It is further divided into:

• episodic memory (autobiographical knowledge, i.e. knowledge about oneself and one's own experiences)
• semantic memory (school or factual knowledge about the world, regardless of one's own experience)

Non-declarative memory (also called implicit memory) stores implicit content. These are not directly accessible to consciousness and therefore cannot be called up in language. These include, for example, highly automated skills such as driving a car, cycling, skiing or tying your shoelaces (procedural memory).

How does memory work?

Around 10 million signals from the sensory organs reach our brain every second, but not all of them are worth storing and remembering later. For this reason, only a selection of the signals helps, which divides the impressions into different categories. A first distinction is made into the categories: "known" and "unknown". Then our brain decides whether the impressions are worth remembering and remembering so that we can call them up again at a later point in time.

There is no clearly definable structure in the brain for memory. Rather, a network of nerve cells is responsible for the ability to remember and remember, which extend over different areas of the brain. During memory processes, different areas of the brain are therefore active at the same time.

For example, the basal ganglia, (pre-) motor and cerebellar (cerebellar) structures are responsible for procedural memory. The amygdala and the hippocampus are important for semantic memory and episodic content. The amygdala stores memories with emotional content.

The frontal and temporal regions of the right hemisphere are responsible for processing episodic memory, while the same regions of the left hemisphere are responsible for processing content in semantic memory. The cerebellum is also involved to an increasing or decreasing degree.

The hippocampus in the anterior medial temporal lobe is essential as a buffer for data that is to be transferred to long-term memory, in order to be able to store new information.

In order to be able to call up memory content, the functionality of the corpora mammillaria (belonging to the diencephalon) is important.

What problems can memory cause?

In the case of memory disorders, the ability to remember or remember is impaired. The trigger can for example be trauma, for example an accident.

A retrograde amnesia describes the memory loss for the time before a certain event (such as an accident), an anterograde amnesia the memory loss for the time after this event.

If the short-term memory fails, those affected cannot remember directly preceding conversations or events, while older events, some of which were years ago, are precisely remembered. Short-term memory increasingly decreases with age. Those affected then prefer to concentrate on events that occurred long ago.

Memory disorders are not only possible through injuries that have an external effect (traumatic brain injury), but also through internal injuries such as vascular bleeding during a stroke. Degenerative changes such as Alzheimer's disease or dementia are also common causes of impaired memory. And last but not least, drugs (neuroleptics) and alcohol ("film tears" after a night of drinking, Korsakoff syndrome) lead to memory disorders.

In the case of damage to the amygdala, memory contents associated with emotions are disturbed. Those affected can only remember pure facts without any emotional content.

Tags:  stress alcohol drugs Diseases