Mind Wandering and Brain Fitness
A recent study has been mentioned on several blogs – it shows that when people let their mind wander, their mood gets worse.
What does that have to do with brain fitness?
Mind wandering of the kind we’re talking about is associated with increased activity in a group of structures in the brain called the default network. It’s called that because it was discovered when researchers left the scanners on when people were being evaluated for brain activity in other experiments. When people weren’t actively doing a task, investigators found that a set of structures in the brain tended be more active. Conversely, when people are focusing on a specific task or actively directing their attention, activity in this network decreases. If their minds wander to upsetting or worrying things, their mood may worsen.
When I give talks to groups of seniors about brain fitness, I often ask them what their number one complaint is. It mirrors what I see in patients who come to the clinic for evaluation of memory problems. “I went into the other room for something, but forgot what it was.” “I opened the refrigerator but forgot what I wanted to get out.”
The diagnosis is something I would call loss of the ability to maintain an intention. From talking to people with the complaint, it seems likely to me that what happens is that their minds drift to an introspective or planning state (perhaps reflecting a shift to default network activity) and thus the object of the intention (what they were going to get in the other room or out of the refrigerator) is lost.
Why does this happen more as we get older? Declines in the central dopaminergic system have documented with increasing age, and that system is known to be intimately involved in both attention and motivation. A decline in the activity of that system might explain the shift – maintaining the object of the intention in memory isn’t as automatic. Most older persons can remember what they are going to get, they just need to consciously maintain the object in their thoughts by rehearsing it.
What is the answer? Some researchers have studied the use of dopaminergic drugs (often the same medicines used to treat attention deficit disorder) to improve apathy in older persons. Many stimulant medications act on dopamine, and improve focus and sustained attention. It’s an open question whether these medications should be prescribed for this purpose.
Perhaps a better and unexplored alternative is to work on ways to explicitly train older persons with memory strategies for just this kind of problem. If you rehearse (say over to yourself multiple times) what you want to remember, you can improve your ability to remember almost anything. Another possibility is meditation – some kinds of meditation are associated with changes in the default network’s activity. It may be possible to improve a person’s ability to deactivate it and activate alternative sensory networks, with a resulting improvement in memory.
