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Memory

life science Maturity 11-13 Vital Level 3 Next article →

Memory is the mental faculty used to encode, store, and retrieve information. This process allows us to retain data over time to influence our future actions. Without memory, humans could not develop language, maintain relationships, or form a personal identity. Scientists often view memory as an information processing system. This system relies on different stages: a sensory processor, working memory, and long-term memory.

Memory
Memory

The process begins with the sensory processor. This stage receives chemical and physical stimuli from the outside world. It allows us to attend to information with varying levels of focus. Following this, working memory acts as an encoding and retrieval processor. It takes stimuli and encodes them into either explicit or implicit functions. Working memory also pulls information from previously stored material to help us process the present. Finally, long-term memory functions to store this information through various categorical systems.

multistore model
multistore model

Memory is divided into two main types: declarative and non-declarative. Declarative memory, also called explicit memory, involves the conscious storage and recollection of data. This includes semantic memory, which encodes specific meanings, and episodic memory, which records information on a spatial and temporal plane. In contrast, non-declarative or implicit memory involves unconscious storage and recollection. Examples include procedural memory, which is the slow, gradual learning of skills without conscious attention. Another example is priming, where specific responses are subliminally aroused from memory.

Working memory model
Working memory model

Sensory memory is the very first stage of this system. It holds information from the senses for less than one second after perception. This process is an automatic response and is outside of cognitive control. There are three specific types of sensory memory. Iconic memory is a fast-decaying store of visual information. Echoic memory is a fast-decaying store of auditory information. Haptic memory serves as a database for touch stimuli.

Brain regions in memory formation updated
Brain regions in memory formation updated

Researchers have used experiments to define the limits of these stages. In 1963, George Sperling used a "partial report paradigm" to study sensory memory. He presented subjects with a grid of 12 letters in three rows. He found that while sensory memory capacity was approximately 12 items, it degraded within a few hundred milliseconds. Regarding short-term memory, George A. Miller conducted research at Bell Laboratories in 1956. He famously identified the capacity of short-term memory as 7±2 items. Modern perspectives suggest the limit may actually be lower, around 4 to 5 items.

Memory-Warner-Highsmith
Memory-Warner-Highsmith

We can influence how well we remember things through specific methods. One method is chunking, which increases short-term memory capacity. This involves grouping items into meaningful sets, such as breaking a ten-digit phone number into three smaller groups. Another method involves the level of processing. "Deep" encoding, which focuses on meaning, creates richer and more connected memories than "shallow" encoding. Context dependence also plays a role. This principle suggests that remembering is easier when the environment during testing matches the environment during study.

DNA methylation and demethylation molecular mechanisms
DNA methylation and demethylation molecular mechanisms

Memory is not a perfect system and can be corrupted by several factors. Physical pain has been identified as a condition that impairs memory in both humans and animals. Additionally, the amount of attention given to new stimuli can reduce how much information is encoded. Physical damage to brain regions like the hippocampus can also corrupt the storage process. Finally, the retrieval of information can be disrupted by decay within long-term memory. Accuracy and capacity are constantly affected by normal functioning, decay, and brain damage.

At a molecular level, long-term memory is a complex biological process. It requires gene transcription activation and the synthesis of new proteins. Research shows that long-term memory depends on activating memory-promoting genes while inhibiting memory-suppressor genes. This dual regulation is achieved through a major mechanism called DNA methylation. In rats, strong long-term memory was linked to the modified expression of 9.17% of the hippocampal genome. This shows that memory is deeply tied to the very instructions within our cells.

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🖼️ Images & Media (10)
File:Memory.gif
Memory.gif
File:Memory-Warner-Highsmith.jpeg
Memory-Warner-Highsmith.jpeg
File:multistore model.png
multistore model.png
File:Working memory model.svg
Working memory model.svg
File:Garten des Vergessens.jpg
Garten des Vergessens.jpg
File:Early LTP mechanism.png
Early LTP mechanism.png
File:DNA methylation and demethylation molecular mechanisms.png
DNA methylation and demethylation...
File:Regulatory sequence in a promoter at a transcription start site with a paused RNA polymerase (no caption).jpg
Regulatory sequence in a promoter at a...
File:Brain regions in memory formation updated.jpg
Brain regions in memory formation updated.jpg
How does your memory work.webm
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