The Neurobiology of Habits
In this issue, I pull together quotes from books and articles to explore the neuroscience behind habit formation.
Books on the Neurbiology of Habits
Charles Duhigg writes in The Power of Habit:
Deeper inside the brain and closer to the brain stem--where the brain meets the spinal column--are older, more primitive structures [than the neocortex]. They control our automatic behaviors, such as breathing and swallowing, or the startle response we feel when someone leaps out from behind a bush. Toward the center of the skull is a golf ball-sized lump of tissue that is similar to what you might find inside the head of a fish, reptile, or mammal. This is the basal ganglia, an oval of cells that, for years, scientists didn’t understand very well, except for suspicions that it played a role in diseases such as Parkinson’s. In the early 1990s, the MIT researchers began wondering if the basal ganglia might be integral to habits as well.
The internalization of a routine “relied upon the basal ganglia, the brain probes indicated. … The basal ganglia … stored habits even while the rest of the brain went to sleep.”
“Habits never really disappear. They’re encoded into the structures of our brain”
“That craving is what powers the habit loop”
“But countless studies have shown that a cue and a reward, on their own, aren’t enough for a new habit to last. Only when your brain starts expecting the reward--craving the endorphins or sense of accomplishment--will it become automatic to lace up your jogging shoes each morning. The cue, in addition to triggering a routine, must also trigger a craving for the reward to come.
James Clear in Atomic Habits:
... dopamine is released not only when you experience pleasure, but also when you anticipate it. Gambling addicts have a dopamine spike right before they place a bet, not after they win. Coaine addicts get a surge of dopamine when they see the powder, not after they take it. Whenever you predict that an opportunity will be rewarding, your levels of dopamine spike in anticipation. And whenever dopamine rises, so does your motivation to act. It is the anticipation of a reward--not the fulfillment of it--that gets us to take action.
Articles on the Neurobiology of Habits:
The role of dopamine in reward and pleasure behaviour--review of data from preclinical research:
The role of dopamine in the reward process was classically associated with the ability to experience pleasure; recent data suggest a more motivational role. Dysfunction of the dopamine transmission in the reward circuit is associated with symptoms such as anhedonia, apathy and dysphoria found in several neuropsychiatric disorders, including Parkinson's disease, depression, drug addiction, and neuroleptic-induced dysphoria.
Endocannabinoid Modulation of Orbitostriatal Circuits Gates Habit Formation
It’s well known that habit formation coincides with reduced prefrontal cortex activity and increased basal ganglia activity. This study shows the role of endocannabinoids in the movement from goal directed, prefrontal cortex activity to habitual, basal ganglia activity. In particular, they were able to show that the deletion of CB1 (cannabinoid type 1) receptors prohibited the ability to form habits. In sum, the paper reinforces the idea that the prefrontal or orbital frontal cortex is involved in goal directed behavior and the basal ganglia is involved in habitual behavior. Further, the deletion of the CB1 receptors in the orbital frontal cortex projecting to the dorsal striatum inhibits habit formation.
Creatures of Habit: The Neuroscience of Habit and Purposeful Behavior
Activity in the orbitofrontal cortex is necessary for switching from habitual to goal-directed strategies. This shifting is dependent on the plasticity of corticostriatal connections, a process mediated by multiple neurotransmitter systems, including dopaminergic, glutamatergic, and endocannabinoid signaling
The role of dopamine in reward and pleasure behaviour – review of data from preclinical research
“Di Chiara and North (46) proposed that the reward pathways can be divided into two parts with the opioid system being associated with consummatory, satiated aspects of reward including sedation, rest and bliss, while the dopaminergic system is associated with incentive, preparatory of acquisition aspect of reward typically experienced as a sense of thrill, urgency, or craving.
In doing so, dopamine plays a role in initiating and establishing neuroplastic changes associated with developing behavioural strategies necessary to adapt to novel stimuli.”
The Neuroscience of Habits: Using neuroscience to understand habit loops.
As Dr. Jud described in our interview, “the prefrontal cortex of our brain goes offline” when we’re hungry, angry, lonely, or tired (HALT).
Putting Habit Theory into Practice
I’ve become more and more interested lately in the neuroscience behind habit formation. I started noticing little things long ago about the kinds of stimulants that I put into my body (sugar, caffeine) and the role that they would play with my mood throughout the day. Sugar was a great way to temporarily relieve lethargy, but that lethargy would only return 20-30 minutes later with vengeance. What I noticed, and what I was reading, confirmed that sugar incited the desire for more sugar. Then I started noticing this in other places: streaming shows incited the desire for more shows. There was never a sense of fulfillment or satiety. This desire for more without ever being satisfied can be explained by the role of dopamine as a neuromodulator: whenever we’re craving something based on a cue (the streaming show’s “up next” or the chocolate in our cupboard), that craving is dopamine kicking in to encourage us to engage in the behavior. There are other neuromodulators that are involved with satisfaction such as the neuropeptide endorphin that is released with exercise, thus arriving after the performance of the activity, but it’s dopamine that creates the affective state of craving.
Self regulation, then, involves becoming conscious of the cue that has incited the release of dopamine and pausing for a moment, and describing the activity in order to move that activity out of the habit center of the basal ganglia and into the prefrontal cortex for evaluation by the goal directed center of the brain. This can be accomplished by asking ourselves “what am I doing right now? What goal am I trying to achieve” By asking ourselves this question, we become consciously aware of the activity that we’re performing and we disrupt the dopaminergic cycle.
Quick Tip
If you ever find yourself doing something that you might not otherwise want to do (that third consecutive episode of Yellowstone or that third beer), ask yourself “What am I doing? What goal am I trying to achieve?”. You might find, as I’ve found on many occasions, that it’s the dopamine that’s in control and not me.
