Once Iris learned how to forge cheques, there was no turning back. Her new skill set became part of her learned memory. She would never forget the sight of her first set from Tiffany’s. It was forever etched into her visual cortex.
Memory is the ability to use the past in service of the present. It is the sum total of what we remember; experiences, facts, skills and habits. It is the record of a life lived. Experiences that are emotional or prolonged are what our brains deem worthy of saving to long term memory, however our memories are not fixed entities, but rather they are transformed over time, changing as we revisit them and by our current point of view. Long-term memories are stored throughout the brain as groups of neurons that are primed to fire together in the same pattern that created the original experience, and each component of a memory is stored in the brain area that initiated it (e.g. groups of neurons in the visual cortex store a sight).
Remembering requires many parts of the brain to work together. The brains inner layer (hippocampus and parahippocampal regions) work with the brains outer layer (cerebral cortex) to organise, store and retrieve memories. The repeated firing of neural circuits back and forth between the inner brain and the outer brain allows an experience to be recalled and consolidated from short term to long term memories. The simultaneous firing of all these groups constructs the memory in its entirety.
The most commonly associated symptom of Alzheimer’s is memory loss. Alzheimer's does not affect all memory capacities equally.
The first to go is short term memory - the ability to hold information in an active, readily-available state for a short period of time. Next affected is episodic memory -memories of autobiographical events. Then semantic memory -memories of the meanings of words & facts about the world. Lastly, Procedural memory -how to perform tasks and skills.