Dreaming and Habit Formation
May 7, 2013
The caudate nucleus of the brain, part of the basal ganglia buried beneath the cerebral cortex, is known to be involved in habit formation. An example of habit formation comes from the field of navigation. When we travel to a place (say a new supermarket) for the first time, we make use of our hippocampus, our brain’s major memory center, which contains a route map similar to the ones we use on Mapquest or Google Map. As we become accustomed to going to that particular supermarket, we learn specific landmarks and directions (turn right at the Mobil station; turn left at the 7/11). Accompanying our behavioral shift from “wayfinding” to “route-following”, activity in our brain shifts from the hippocampus to the caudate nucleus. In the process we establish a habit: going to a new supermarket.
How do we form new habits? Evidence suggests we may do this while sleeping. Brain imaging studies show activation of the caudate nucleus during REM sleep, also known as dream sleep. REM sleep is involved in the processing of emotional memories (as discussed in an earlier blog). Formation of new habits in the caudate nucleus involves the processing of emotions, as we attempt to master the details of a new behavior.
In his best-selling book, The Power of Habit, Charles Duhigg, an investigative reporter for The New York Times, describes “habit loops”, which begin with a cue (hunger, in the case of the supermarket), involve a behavioral routine (getting to the supermarket), and end with a reward (food, in this case).
The golden rule of habit change, as presented by Duhigg, is to use the same cue (e.g., hunger), to provide the same reward (e.g., food), but with a different behavioral routine. In the supermarket example, we learn to follow specific landmarks rather than going by a diagrammatic map.
People with PTSD sometimes engage in either risk-taking or avoidant behaviors (habits) which are not helpful toward their recovery. Our goal in successfully treating PTSD, according to the golden rule of habit change, may be to use the same cue and the same reward, but with different behaviors in between. PTSD sufferers have a hard time eliminating their dysfunctional habits, for reasons that are not yet fully understood.
Dream revision may be helpful in this regard. A recurrent nightmare is a kind of dysfunctional habit carried out by our brains while we sleep. We need to break this habit in order to allow the dreaming mechanism to do its work of forming new (functional) habits. The process of establishing new habits requires effort and persistence during waking life by the PTSD sufferer. Blocking nightmares serves as a kind of reset button to allow the habit formation system to function normally again.
Furthermore, success at changing (and eliminating) a recurrent nightmare gives the PTSD sufferer confidence that their daytime habits can also be changed. If you can manage to take charge of your dreams, you may be able to take charge of your waking life as well.
