Memory Formation and Preservation

When we experience something, it's converted into a pulse of electrical energy that travels along a network of neurons.
Information initially goes to short-term memory:
- Available for only seconds to minutes.
Then, transferred to long-term memory:
- Via areas like the hippocampus.
- Then to several storage regions across the brain.

Neurons communicate at synapses using neurotransmitters.
Long-term potentiation:
- If two neurons communicate repeatedly, the efficiency of communication between them increases.
- Considered a mechanism for long-term memory storage.

As we age, synapses weaken, impacting memory retrieval.
Theories behind deterioration:
- Brain shrinkage: Hippocampus loses about $5\%$ of its neurons per decade, resulting in a $20\%$ loss by 80 years old.
- Drop in neurotransmitter production, such as acetylcholine, which is vital for learning and memory.
Age affects memory-making abilities
- Memories are encoded most strongly when we're paying attention, when we're deeply engaged, and when information is meaningful to us.
- Mental and physical health problems, which tend to increase as we age, interfere with our ability to pay attention and thus act as memory thieves.

Chronic stress = body on hyperalert
Evolutionary response: stress chemicals mobilize energy and increase alertness
Chronic stress: floods body with chemicals, resulting in loss of brain cells and an inability to form new ones, which affects our ability to retain new information.

People who are depressed are $40\%$ more likely to develop memory problems.
Low levels of serotonin may reduce attention to new information.
Dwelling on sad events makes it difficult to pay attention to the present impacting short-term memory storage.

Connected to depression
Harvard School of Public Health study: older people with high social integration had a slower rate of memory decline over six years.
Social interaction may give brain a mental workout.
Use brain or risk losing it.