Attention and memory
Encoding, consolidation and retrieval
How memories are formed and kept
Key takeaway for patientsMemory depends on attention first and sleep second. Many causes of poor memory are treatable, which is why a persistent change is worth assessing.
Memory begins with attention. What is attended to is held briefly in working memory, which depends on the prefrontal cortex and on the neurotransmitters acetylcholine, dopamine and noradrenaline.
The hippocampus encodes new information and, during sleep, replays it so that it is consolidated into long-term stores in the cortex. Retrieval then depends on cues and on the state of the brain at the time.
Key steps in forming a memory
- Attention
- Selects what enters working memory.
- Encoding
- The hippocampus binds the elements of an experience together.
- Consolidation
- Sleep, slow-wave sleep in particular, stabilizes the memory.
- Retrieval
- Cues reactivate the stored pattern.
Factors that impair attention and memory
Many of the common causes are reversible:
- Sleep deprivation
- Impairs both attention and consolidation.
- Stress and low mood
- Divert attention and alter the function of the hippocampus.
- Medical causes
- Thyroid disease, vitamin B12 deficiency, anemia and some medicines.
- Aging and vascular risk
- High blood pressure and diabetes affect the brain’s small vessels.
Clinical management and physician guidance
Assessment looks for reversible causes before anything else.
- Cognitive and laboratory assessment
- History and screening tests, with thyroid function, B12, blood count and metabolic markers.
- Physician-guided care
- Sleep, vascular risk, mood and any deficiency are addressed as your physician decides.
- Monitoring and follow-up
- With referral for specialist assessment where indicated.
Research focus in memory
| Core focus area | Biological target | Clinical relevance |
|---|---|---|
| Working memory | The prefrontal cortex | Holding information in mind |
| Encoding | The hippocampus | Formation of new memories |
| Consolidation | Slow-wave sleep | Transfer to long-term storage |
| Neuromodulators | Acetylcholine and dopamine | Attention and clarity of signal |
Frequently asked questions
- Is forgetfulness always a sign of something serious?
- No. Lapses of attention are common, especially with poor sleep or stress.
- Why does sleep matter for memory?
- Memories are consolidated during sleep, deep sleep in particular.
- When should I be assessed?
- If changes in memory are persistent, progressive or noticed by others.
Academic references and literature
- Squire LR (2004). Memory systems of the brain: a brief history and current perspective. Neurobiol Learn Mem, 82(3), 171-7. PMID 15464402.
- Diekelmann S, Born J (2010). The memory function of sleep. Nat Rev Neurosci, 11(2), 114-26. PMID 20046194.
- Baddeley A (2003). Working memory: looking back and looking forward. Nat Rev Neurosci, 4(10), 829-39. PMID 14523382.
This guide belongs to the Cognitive program