Ken Kosik is co-Director of the Neuroscience Research Institute at the University of California Santa Barbara. His research focuses on “both the mechanisms of neuronal plasticity and its impairment in neurodegeneration.” At April’s Brain conference Kosik talked about The Adult Brain and Memory: How Learning Protects Against Alzheimer’s.
Did you know that 10 to 15 percent of people over 65 years of age suffer from some form of neurodegenerative disease, and the ratio becomes one in two for people over 85 years of age. Many of us tend to think of dementia as one of those diseases, yet Kosik says that dementia “is a symptom, like a fever” and it simply “means that cognition is not normal.” It is necessary and important to ask “What kind of dementia?” He went on to note that “forgetting is part of what the brain does”, though there is a “gray zone between a normal and abnormal range of forgetting, and this gray zone is what worries people.”
In Alzheimer’s the brain shrinks, and in the shrinking process certain areas are impacted more than others. The limbic system, which handles emotions, is targeted, specifically the hippocampus (memories) and especially the amygdala (emotions). The cerebral cortex is also impacted, though the cerebellum and primary motor and sensory strip tend to be left alone. As the brain shrinks, the sulci (grooves between the folds) widen, and neurons become “swollen, twisted and distorted”. The American Health Assistance Foundation provides a clear explanation and graphic of what happens to the brain with Alzheimer’s. For a hands-on experience, take the Alzheimer’s Association’s Inside the Brain: An Interactive Tour.
Kosik also mentioned mild cognitive impairment (MCI). People with MCI function fine in daily life but have memory issues that go beyond what is considered normal for their particular age. Usually this is obvious to those around the individual, though the individual may not be aware that there is anything out of kilter. Kosik likened a line from John Updike’s Free in the January 8, 2000 issue of The New Yorker to MCI: “…one’s own ability to improvise could no longer be trusted.”
In the progression to Alzheimer’s, Kosik noted that
- the ability to think on the spot diminishes
- there is a move to regression
- the mind is “emptying out”
While none of this is pleasant to ponder, studies have provided some conclusive data about Alzheimer’s that can be put to use in attempting to combat the onset of the disease.
- Education is a plus
- Sustained long-term stress is a negative
- Challenging your brain with something you do not normally do is a plus
The most fascinating study Kosik mentioned is that of transgenic mice, i.e. genetically engineered mice. These particular mice were genetically engineered to get Alzheimer’s. Alzheimer’s consists of neurofibrillary tangles inside the neurons and amyloid plaques between the neurons. It turns out that if the mice are placed in enriched environments, the growth of the amyloid plaques is slowed. (Slides 10 through 13 in the Interactive Brain Tour provide an excellent description of plaques and tangles.)
Kosik left us wondering just where do memories go? Do they disappear or do they just become inaccessible. He says that if it’s just an access problem, we might be able to work on retrieval strategies.