Mice, humans, and memories

Lane Simonian

There may be many reasons why treatments for Alzheimer's-like disease work in mice but not in human beings, but one of them is that mice are given only one of the many factors that contribute to Alzheimer's disease (most often amyloid).  You remove that one factor in mice (whatever it is) and you cure the mouse of Alzheimer's disease.  But in humans often times several factors are causing the disease.

The following study while in mice is nevertheless instructive:

Memories retrieved in mutant ‘Alzheimer’s’ mice

Study suggests that patients with Alzheimer's disease can still form memories, raising hopes of new treatments.

People with Alzheimer's disease may forget faces or where they left familiar objects because their brains cannot find where they put those memories, a study in mice suggests.

https://www.nature.com/articles/nature.2016.19574

The less than perfect analogy that is often given is a libary without call numbers: all the books are still there but without the call numbers a person cannot find them.

The key compound in memory retrieval is acetylcholine.  Many Alzheimer's drugs have an early positive effect because they inhibit the breakdown of acetylcholine but as the disease progresses the problem is the lack of production of acetycholine due to oxidation and nitration.  These processes are partially reversible.  Certain types of memory such as recognition of objects, places, people's faces, repetitive memory (such as numbers and the alphabet), sense of time, etc. can improve whereas other types of memories (perhaps because of their location in the brain) such as short-term memory and logically processing and putting in order information are more stubbornly resistant to change.

I am not sure which produces a greater burden for an individual: thinking that there is nothing that can be done to change Alzheimer's disease or believing that something can be done to change the course of Alzheimer's disease.  The former may produce a fatalistic acceptance of the disease; the latter brings a seemingly endless pursuit of something that works.