Source: Wikimedia/Life Sciences Database

A new study from the University of California, Los Angeles (UCLA) reports that improves functional connectivity between the cerebellum and other brain regions in ways that may compensate for underlying dysfunctions associated with . This study, “Mechanisms of Cognitive Behavioral Therapy for Obsessive-Compulsive Disorder Involve Robust and Extensive Increases in Brain Network Connectivity,” was published online Sept. 5 in the journal Translational Psychiatry.

therapy (CBT) is typically a short-term, goal-oriented type of treatment that aims to help patients address specific maladaptive patterns of thinking and behavior using a variety of techniques. disorder (OCD) is a common disorder marked by difficult-to-control obsessive thoughts and that someone with OCD is compelled to repeat over and over again.

The cerebellum (Latin for "little brain") was first identified by Leonardo da Vinci in 1504 after he made wax casting of the human brain and observed two small brain hemispheres neatly tucked under the relatively colossal left and right hemispheres of the cerebrum (Latin for "brain"). Cerebellar is the sister word to cerebral and means, "relating to or located in the cerebellum."

Historically, neuroscientists believed that the cerebellum was a "non-thinking" part of the brain primarily responsible for fine-tuning muscular coordination that was not involved in . However, this outdated view of the cerebellum is rapidly changing. For example, Jeremy Schmahmann of Harvard Medical School is an expert in ataxia who first defined Cerebellar Cognitive Affective Syndrome (CCAS) and "Dysmetria of Thought." Schmahmann believes that specific microzones within the left and right cerebellar hemispheres may play a role in fine-tuning our thoughts much the same way they fine-tune bilateral motor coordination.

During the recent UCLA study on CBT and brain connectivity, 43 patients with OCD underwent four weeks of daily cognitive behavioral therapy to learn personalized techniques each person could use to break his or her unique cycles of obsessive thinking and compulsive behaviors. There was also a control group of people with OCD who were put on a waiting list to receive CBT at a later date and another control group without OCD who never received CBT.

Source: Wikimedia/Life Sciences Database

At the outset of this experiment, all study participants underwent functional magnetic resonance imaging (fMRI) brain scans. After one month of CBT, the researchers rescanned all of the participants with OCD in the fMRI. As mentioned earlier, the UCLA team observed robust increases in the functional connectivity between the cerebellum and other brain regions—along with a reduction of OCD symptoms in the group who had received intensive CBT—but not in the group that had been put on the waiting list.

More specifically, when the UCLA neuroscientists compared the fMRI brain scans of the participants with OCD who had received CBT before and after treatment, they observed the strongest increase in functional connectivity between the cerebellum and the prefrontal cortex, as well as the cerebellum and the striatum. The authors sum up their findings in the discussion section of their latest paper:

“In summary, mounting evidence points to cerebellar activity and connectivity playing a role in OCD pathophysiology and/or treatment. In our study, several connectivity changes involving cerebellum resemble specific effects of CBT seen in other disorders. The cerebellum has a role in motor functions, from movement coordination to response-inhibition and is instrumental in acquisition of goal-directed behavior and optimization of motor responses. In addition, the dysmetria of thought theory posits cerebellar modulatory involvement in cognition and emotion. Moreover, CBT-relevant effects may be mediated by the vermis through formation of new unconditioned–conditioned associations in to enable appropriate responses to new stimuli and situations. Although much remains to be elucidated, current views on functional anatomy in conjunction with previous OCD neuroimaging are consistent with the cerebellum having a key role in CBT-response.”

In a statement, Jamie Feusner, director of the Adult Obsessive-Compulsive Disorder Program at the Semel Institute for Neuroscience and Human Behavior at UCLA and the study’s senior author concluded, “The changes appeared to compensate for, rather than correct, underlying brain dysfunction. The findings open the door for future research, new treatment targets and new approaches.” Teena Moody, a UCLA research associate and the study’s first author, added, “The results could give hope and encouragement to OCD patients, showing them that CBT results in measurable changes in the brain that correlate with reduced symptoms.”

"We don't know exactly what the cerebellum is doing. But whatever it's doing, it's doing a lot of it." —Richard Bergland, M.D. (1932-2007)

On a personal note about this groundbreaking UCLA study: I’ve been researching and writing about the cerebellum for over a decade. My late father, Richard Bergland, was a 20th-century neurosurgeon, , and author of The Fabric of Mind (Viking). Because the cerebellum is only 10 percent of brain volume but houses well over 50 percent of the brain's total neurons, my dad would often say “We don’t know exactly what the cerebellum is doing. But whatever it’s doing, it’s doing a lot of it.”

In 2005, my father and I created a split-brain model we called “up brain-down brain” which I published in The Athlete’s Way (St. Martin's Press) as part of a dual-pronged prescriptive that specifically targeted cerebral (up brain) and cerebellar (down brain) functions in ways similar to CBT with the goal of optimizing mindset and behavior.

Source: Photo and illustration by Christopher Bergland (Circa 2009)

Unfortunately, when the "Bergland split-brain model" was published over a decade ago, our radical ideas about cerebellum-cerebrum interplay were widely rejected and the book flopped. It was disappointing. That said, when my father died in 2007, I made a vow to continue his life's work and to keep my antennae up for any -edge cerebellar research with the hope of someday having more empirical evidence to answer the age-old riddle of what all those neurons in the cerebellum are actually doing. Needless to say, I was thrilled to read about the latest study from UCLA, which identifies novel ways that the cerebellum is, in fact, involved in much more than simply fine-tuning muscle coordination and maintaining balance.

After years of incessantly thinking about cerebellar structure and connectivity with the cerebrum...one day in 2009, I had an epiphany as I was walking home from the gym. That “Aha!” moment resulted in a very basic "Super 8" brain map (above), which I drew to illustrate the importance of functional connectivity of the cerebellum to other brain regions. In particular, the yellow and green 'infinity eights' with Asteroids-inspired rocketship arrows are drawn to represent a multi-directional feedback loop that flows top-down and bottom-up between the posterior cerebellum and prefrontal cortices.

To read more on the ongoing evolution of the "up brain-down brain" model check out my Psychology Today blog post “The Split-Brain: An Ever-Changing Hypothesis.”