LTM

In psychology, LTM refers to long-term memory, a component of the human memory system responsible for storing information over extended periods, from days to decades. It contrasts with short-term or working memory, which holds information temporarily for processing.

The formation of long-term memories involves encoding, consolidation, storage, and retrieval. Encoding transforms experiences into stable representations; consolidation strengthens traces, often during sleep; storage preserves them; retrieval allows access, sometimes aided by cues. The capacity and duration are variable and influenced by attention, repetition, and emotional significance.

LTM is subdivided into declarative (explicit) and non-declarative (implicit) memory. Declarative memory includes episodic memory for personal events and semantic memory for facts. Non-declarative memory includes procedural memory for skills, priming, simple classical conditioning, and other implicit learning.

Neural bases: the hippocampus and surrounding medial temporal structures are crucial for forming new declarative memories, especially episodic ones, while semantic memory relies more on cortex networks. The basal ganglia and cerebellum support procedural memories; the amygdala modulates emotional memories. Sleep, especially slow-wave and REM stages, promotes consolidation.

Development and aging: LTM matures through childhood, with improvements in episodic recall during adolescence. Aging often reduces episodic retrieval and slows encoding, while semantic memory can remain relatively preserved. Disorders such as Alzheimer’s disease and other dementias disproportionately affect long-term memory.

The concept of LTM forms part of broader theories of memory; memories are not perfect records but reconstructive. External cues facilitate retrieval, and memories can be altered upon recall through reconsolidation.