The school of pop psychology pretends that the right brain-left brain divide is clear-cut, but we are much more complex than that. The "simple" task of looking at a picture of a cat and saying its name out loud involves large areas of the brain. The image of the cat must strike the back of both eyes and travels over the optic nerves where they then cross and enter the brain. The signal travels to the very back of the brain, and then the information on the right side of the brain must cross to the left side where both sets of information are combined and compared to a "database" of previously stored images.

Our brains store everything we have seen and remembered for just such a moment. Is there anything there that looks like the cat? Fur, claws, a meow, fond memories, a nasty scratch. Once identified, the information travels forward to the part of the left side of the brain that controls speech production. The muscles that control our breathing, tongue and lips all have to be coordinated to say the simple one syllable word, "cat." This all happens in less than a second.

Our brain is packed with pathways that carry very specific information. A stroke may be highly selective and attack just one specific part of the brain. However, aging and dementia are processes that slowly cause the deterioration of nerve cells throughout the brain.

But dementia and aging do not affect all parts of the brain equally. Alzheimer's disease, especially, does not affect the entire brain at once but starts in the part of the brain that creates new memories. Most people know that as we age we can remember with vivid clarity things from the past, while the events of a few hours earlier may be a total blur. Depending on which part of the brain is affected, different skills will be preserved or impaired in different types of dementia. This gradual reformation is what may allow the emergence of artistic abilities.

Our ability to communicate relies primarily on the use of verbal and writing skills, which are then lost when cognitive skills decline. But, creative arts like music or painting can bypass the "verbal pathways" and access other pathways that become available for communication. Dr. Bruce Miller, Clinical Director of the Memory and Aging Center at the UCSF has studied how the brain functions in patients with newly acquired abilities. Dementia preferentially attacks the frontal and temporal parts of the brain at first, only involving the "artistic" parietal and occipital lobes later in the disease.

What a person sees and where they have seen it over their entire lifetime - the same process as remembering "cat" -- is stored in these "artistic parts of the brain. Painting is predominantly a visual process that involves the parts of the brain that are spared for most of the course of dementia. As a result, the people with dementia will often express these visual memories through painting.