langtímaminni

Langtímaminni, or long-term memory, refers to the storage of information over extended periods, from days to decades, with a capacity that far exceeds working memory. It contrasts with short-term memory, which holds data briefly for immediate use. Long-term memory depends on encoding quality and consolidation, processes that stabilize memories after initial acquisition. Deeper encoding, effective organization, and retrieval practice strengthen retention, and sleep supports consolidation.

Long-term memory is commonly divided into explicit (declarative) memory and implicit (nondeclarative) memory. Explicit memory includes episodic memory, which records personal events and experiences, and semantic memory, which stores facts and concepts. Implicit memory comprises procedural memory for skills, priming effects, and conditioned responses that can operate without conscious awareness.

Neuroanatomically, the hippocampus and surrounding medial temporal structures are critical for forming new explicit memories. Over time, memories become integrated into distributed cortical networks. Retrieval relies on interactions between the prefrontal cortex and hippocampus, aided by retrieval cues. Consolidation involves synaptic changes and system-level reorganization, processes that unfold over minutes to years and are facilitated by sleep.

Aging can modestly affect episodic memory while semantic memory often remains robust. Impairments can occur in neurological conditions such as Alzheimer's disease, which damages medial temporal regions, and in amnesia, which can involve anterograde or retrograde memory loss. Strategies such as repetition, elaboration, mnemonic devices, and external aids can support retrieval and durability of long-term memories.