Short answers, pulled from the story.
George Sperling discovered that sensory memory holds approximately twelve items but degrades within a few hundred milliseconds. His partial report paradigm demonstrated that participants could see more than they could verbally describe after viewing a grid of letters for only a fraction of a second.
The hippocampus is essential for consolidating short-term information into permanent storage as shown by patient Henry Molaison who underwent surgery removing most of his hippocampus. Modern research indicates the hippocampus may be involved in changing neural connections for periods lasting three months or longer after initial learning and requires gene transcription activation by 2015.
DNA topoisomerase 2-beta activity triggers double-strand breaks in immediate early genes within about fifteen minutes to two hours during associative fear memory tasks in mice. Approximately six hundred regulatory sequences in promoters depend on these breaks initiated by TOP2B for activation while about eight hundred regulatory sequences in enhancers also rely on them.
Fourteen-month-olds' memories for action sequences last up to four months according to studies using deferred imitation techniques. Nine-month-olds can recall actions of a two-step sequence in correct temporal order while six-month-olds struggle with this task but can recall information after a twenty-four-hour delay.
Alzheimer's disease remains a primary concern regarding memory loss especially as it is a hallmark symptom of aging and involves qualitative differences from normal aging memory loss. Research distinguishes normal aging memory loss qualitatively different from that associated with clinical diagnosis where older adults tend to exhibit deficits on tasks involving knowing temporal order or source memory circumstances.