Superfluidity and the Synergy of Your Four Brain Hemispheres

Most people assume humans only have two brain hemispheres—but we actually have four brain hemispheres. There are two "big" hemispheres in the cerebrum that house the cerebral cortex and are commonly referred to as “left brain-right brain.” And there are two smaller hemispheres south of the midbrain called the cerebellum (Latin for “little brain”) which house the cerebellar cortex and fan-shaped Purkinje cells.

The “little brain” is only about 10% of brain volume but houses the majority of the brain’s total neurons. In most mammalian species, there tends to be a consistent ratio of 3.6 cerebellar neurons to every neuron in the cerebral cortex, according to research by Suzana Herculano-Houzel (2010).

This post is divided into three sections: The first section shares anecdotal examples of why the cerebellum and cerebellar Purkinje cells have been a part of my consciousness for as long as I can remember.

The second part of this post shares some hand-made brain maps that illustrate the relationship between both hemispheres of the cerebrum and cerebellum based on a split-brain model I created with my father for The Athlete's Way manuscript back in 2005. This section juxtaposes my "highlighter and Sharpie pen" homemade brain maps with breathtaking state-of-the-art cerebellar maps (Guell et al., 2018, Marek et al., 2018) from last year.

The third section of this post shares autobiographical examples of how I combine cerebro-cerebellar brain maps and my concept of “superfluidity” as a way to inspire my 11-year-old daughter to “Unclamp*” her prefrontal cortex and not overthink. One key to creating superfluidity is to avoid "clamping" up any part of your body or brain. Because of my simple, color-by-numbers brain maps, my daughter can easily visualize the functional connectivity of her four brain hemispheres when she’s practicing sports, writing a school paper, making art, learning a new language, playing a musical instrument, etc.

(*In his legendary lecture-based publication, On Vital Reserves: The Energies of Men. The Gospel of Relaxation (1911), William James gives readers timeless advice: "Unclamp, in a word, your intellectual and practical machinery, and let it run free; the service it will do you will be twice as good.")

Part One: “Think about hammering and forging the muscle memory in your Purkinje cells with every stroke.”

Yesterday, I wrote a post that reported on a new study (Bijanki et al., 2019) which found that electrical stimulation of a bundle of white matter fiber tracts that connect the gray matter of various brain regions in the cerebrum helped anxiety-ridden neurosurgery patients who had to stay awake for a craniotomy procedure feel happy—and even made patients laugh out loud.

The entire time I was writing about this new study yesterday, I wished that I could call my late father, Richard Bergland (1932-2007) on the phone and ask, “Dad, what’s the deal with this new discovery? Why do you think that probing this so-called ‘happy place’ in the brain makes patients burst out in laughter?”

My father was a prominent 20th-century neurosurgeon and neuroscientist who was brilliant at communicating the overlap between empirical evidence he gained by studying animal models in a laboratory with anecdotal observations he made by getting to know his patients before, during, and after brain surgery. In 1986, he published The Fabric of Mind (Viking Adult).

When I was a kid, I’d go to the hospital with my father most Sundays and wait in his office while he did rounds. Afterward, we’d play tennis or squash. This was our weekly ritual for much of my youth, and the only real quality father-son time we spent together back then.

Coincidentally, because I was born in 1966 and my father regularly crossed paths with David Marr—who was a cerebellum pioneer and wrote the milestone paper, “A Theory of Cerebellar Cortex” (Marr, 1969) which posited that cerebellar Purkinje cells were key to learning motor skills—my dad incorporated this knowledge whenever coaching my tennis game throughout the 1970s.

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In 1971, when I was just learning how to handle a tennis racket, the Marr-Albus model of motor learning became the foundation of my father’s approach to teaching me how to master my tennis strokes and serve like a pro.

As a coach, my father always brought his neuroscience background to the court and would say things to me like, “Chris, think about hammering and forging the muscle memory of your Purkinje cells with every stroke.”

In 2009, Piergiorgio Strata wrote a retrospective, “David Marr's Theory of Cerebellar Learning: 40 Years Later,” which made it clear to me why my father was so keen on putting the cerebellum and Purkinje cells in the spotlight when I was first learning about muscle memory as a young tennis player.

One reason the cerebellum intrigued my father was that, throughout history, most experts thought the cerebellum was only involved in motor functions—but my father had a hunch that the cerebellum might be involved in non-motor functions, too.

Unfortunately, this ‘educated guess’ was unsupported by any empirical evidence at the time. Therefore, my father would regularly muse: "We don’t know exactly what the cerebellum is doing. But whatever it’s doing, it’s doing a lot of it."

After I retired from professional athletic competitions, I decided to write a book about neuroscience and sports, The Athlete’s Way: Sweat and the Biology of Bliss (2007), with my father serving as the medical expert. Of course, the human cerebellum would take center stage throughout the manuscript because of its undeniable role in muscle memory and pivotal role in finely-tuning coordinated movements. I also wanted to use my platform as a science writer to get some of my dad’s more radical ideas about the cerebellum published.

Sadly, by the end of his professional career, my father had burned a lot of bridges with his Ivy League colleagues. Full disclosure: My father was a rageaholic who often lacked emotion regulation. Usually, if my father disagreed with someone and things got heated, he’d lose his cool and didn’t have much finesse when it came to workplace politics. By the time he retired in the late 1990s, most people in the medical establishment had said “good riddance" because he was such an irreverent ‘heretic’ who was hell-bent on challenging the status quo of academia's ivory towers.

By the time he'd retired from neurosurgery, my father had basically been blacklisted by most of his colleagues and didn't stand a chance of having his ideas about the brain published in peer-reviewed journals. It was heartbreaking to watch him fall into a state of hopelessness and despair in early retirement.

So, after I broke a Guinness World Record as an ultra-runner and had the cachet to get a book deal on peak performance, a big part of my mission as a science-based writer was to be a stealth messenger of visionary ideas about the cerebellum to a broad general audience.

That said, my determination and ambition to get a book deal with one of the Big Five publishers and write a book about neuroscience and sports was also to prove to my father that I wasn’t just a dumb jock. Since grade school, I’ve had a chip on my shoulder that my older sister had all the “book smarts” and that I got the sibling booby-prize of being a terrible student but having “cerebellar genius.” That said, I’ve always rooted for the cerebellum as an underappreciated underdog. If the cerebellum had a voice, I imagine it would say in a Rodney Dangerfield-inspired way, “I don't get no respect!” For as long as I can remember, I've wanted to give the cerebellum the recognition it deserves.

Part Two: Up Brain-Down Brain: An Ever-Changing Hypothesis

Throughout most of 2005 and 2006, I spoke and emailed with my dad constantly. During lengthy conversations, I picked his brain for detailed neuroscience-based information every day while writing The Athlete’s Way manuscript. Together we created a new split-brain model we called “up brain-down brain.” Our goal was to shift the focus away from “left brain-right brain” by putting the “little brain” in the spotlight. Below is a diagram of this father-son split-brain model.

This brain map illustrates the earliest incarnations of the "Bergland Split-Brain Model" and describes various hypothetical roles each brain region might play within an interconnected cerebellar-cerebral cortex system. (From p. 81 of "The Athlete's Way: Sweat and the Biology of Bliss.")

Source: Photo and layout by Christopher Bergland (Circa 2007)

Tragically, in 2007, my father died suddenly of a heart attack soon after the publication of what we both hoped would be a game-changing book. The only silver-lining of his premature death was that my father passed away thinking our book was going to be a bestseller. Unfortunately, the book never gained traction with a general audience and was a flop.

At my father’s funeral, I made a vow that I’d do my best as a science writer to report on all the latest research regarding the cerebellum in real-time and maintain a timeline of 21st-century advances in cerebellar research to honor my father's legacy. I also made a commitment that I’d continue to advance theoretical ideas about the cerebellum and my concept of “superfluidity" based on life experience and anecdotal evidence (like I'm doing in this post).

As a science writer, walking the tightrope between straight-forward reporting and "storytelling" can be tricky to navigate. Most of the time when I report on science, I avoid using any first-person pronouns and purposely keep the writing strictly evidence-based.

For example, yesterday when I wrote a post, “Have Neuroscientists Found a ‘Happy Place’ in the Brain?” there are purposely no first-person pronouns in the text. Conversely, when I was constructing the format and layout for this post on the treadmill while jogging at the gym this morning, I could see a flowchart of multiple research studies, visual images, and anecdotal examples in my mind's eye that I wanted to bring together under the umbrella of “Superfluidity and the Synergy of Your Brain’s Four Hemispheres."

The reason I decided to compose this post today is that yesterday while I was studying the sagittal view illustration by Bijanki et al. (above) of an electrode probing the cingulum bundle of a neurosurgery patient receiving a craniotomy, I kept visualizing my dad in the O.R. performing “awake” brain procedures.

I also had visualizations of the brain map (below) that I drew back in 2009 which emphasizes the importance of “bridging the gaps between all four brain hemispheres” via white matter fiber tracts. In my mind, it seemed like a funny coincidence that the point where the overlap of the bidirectional feedback loops of green and yellow arrows criss-cross in the cerebrum (“up brain’) is in the same vicinity as the part of the cingulum bundle that Bijanki et al. (2019) targeted with their low-amplitude probe.

This topographical brain map of "cerebro-cerebellar" circuitry illustrates the importance of optimizing the contralateral functional connectivity between both cerebral hemispheres and both cerebellar hemispheres.

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

The rudimentary brain map above offers a bird’s eye view of all four brain hemispheres “squished down” onto one plane so the viewer can visualize how white matter fiber tracts connect the gray matter of brain regions. Each gray-matter encased "egg-shaped orb" represents one of the four brain hemispheres. Like a Russian Doll, you could do a deeper dive within each of these hemispheres to explore the various lobes within each cerebral hemisphere and microzones within each cerebellar hemisphere. From there, you could do another deeper exploration and map neural circuitry.

On January 25, Chloe Williams wrote a Spectrum news report, “New Brain Maps Hint at Cerebellum’s Role in Cognition, Language,” which does an excellent job of summing up why recent advances in cerebellar brain mapping are so exciting. Williams writes:

“The cerebellum has long been known to be responsible for coordinating movements. But scientists are finding it may also coordinate language, cognition, and social behaviors. Yet the structure and function of the region is poorly understood, as is the degree to which it varies among people. A new analysis (Marek et al., 2018) of brain scans highlights variations in the cerebellum at the level of networks of neurons. It also shows how the brain region may cooperate with other regions to govern complex thought.

The resulting images show the extent to which activity in parts of the cerebellum tracks with that in other brain regions in each person. Based on these correlations, the researchers assigned regions of the cerebellum to various neural networks, including the dorsal attention network, the default mode (daydreaming) network and those that control the hands, face and feet. The team also analyzed the scans for the relative timing of brain activity. They found that signals in cerebellar networks lag behind those in the cerebral cortex by 125 to 380 milliseconds. This finding suggests that the cerebellum processes signals originating in the cerebral cortex, such as those involved in learning. ‘Precision mapping’ could be used to understand how individual differences in cerebellar organization contribute to differences in behavior.”

I reported on this study by Scott Marek et al. (2018) and the exquisite cerebellar brain maps (below) created by Xavier Guell et al. (2018) in multiple posts last year. (See "Mapping the Human Cerebellum Reframes Whole-Brain Functions," Cerebellum Studies Challenge Ancient Notions of How We Think," "3 Reasons the "Little Brain" Might Become the Next Big Thing.")

Cerebellum gradients and relationship with discrete task activity maps (from Guell et al., 2018a) and resting-state maps (from Buckner et al., 2011)

Source: Xavier Guell et al./eLife 2018 (Creative Commons)

Part Three: What Is Superfluidity and How Does It Relate to Visualizing Cerebro-Cerebellar Brain Maps?

For the final section of this post, I’m going to shift gears completely and share some autobiographical examples of how I explain my concept of “superfluidity” and “bridging the gaps between all four brain hemispheres” to my 11-year-old daughter on a regular basis. Hopefully, these real-world examples of how concepts of “flow” and neuroscience come together will make this information relatable to people of all ages and walks of life. (For some audio-visual examples of superfluidity see, "Seven Awe-Inspiring Exhibits of Superfluidity in Action.")

Early in my career as an ultra-endurance athlete, I read Mihaly Csikszentmihalyi's seminal bestseller, Flow: The Psychology of Optimal Experience (1990). This book was a godsend for me as a rookie triathlete.

That said, after spending countless hours in the “zone” and creating flow every day of the week, it became clear to me that there were episodic bursts of “transcendent ecstasy” that happened within the flow channel. These orgasmic bursts of connectedness to something much bigger than me in the universe reminded me of experiences I’d had on psilocybin that 'opened my doors of perception' during adolescence.

A big part of my fanatical drive to become an ultra-endurance athlete was rooted in the pursuit of having these ego-dissolving moments of feeling absolutely zero friction, viscosity, or entropy between my thoughts, actions, and emotions combined with a feeling of “oneness” to everything around me while I was running, biking, or swimming. The more time I spent in the “zone” creating a state of flow, the higher the odds were that I’d have moments of superfluidity. The final chapter of The Athlete’s Way is titled “Superfluidity: Chase Your Bliss."

When I retired from professional sports competitions and dedicated myself to becoming a so-called “writer,” I realized that the same moments of superfluidity that happened to me while training or competing in a triathlon also happened at my typewriter. Once in a blue moon, when I was touch typing, it felt as if there was a burst of synergy between all four brain hemispheres that allowed me to convey original thoughts, empirical evidence, visual images, and new ideas in a way that felt “superfluid.” Just like “flow” can occur anytime you dial into the sweet spot between your level of skill and the challenge, episodic moments of superfluidity can occur anytime you're in the zone.

Through the lens of a continuum from clinical neurological disorders to peak performance: Superfluidity of thought, emotion, and coordinated movement is on the opposite end of the spectrum from debilitating cerebellar cognitive affective syndrome (Schmahmann & Sherman, 1998), severe ataxia, and dysmetria of thought (Schmahmann, 1998).

As a parent, one of my primary goals is to structure weekly activities for my daughter that facilitate both flow and superfluidity in multiple arenas while also encouraging her to unwittingly bulk up the gray matter volume in each brain hemisphere and optimize the functional connectivity between her four hemispheres. I have a hunch that these brain changes occur via neuroplasticity and neurogenesis by exposing my daughter to an equal blend of cerebral, cerebellar, and cerebro-cerebellar activities on a weekly basis along with daily moderate-to-vigorous physical activity (MVPA).

I’m well aware that to many onlookers my daughter’s weekly list of “extracurricular” activities—which includes learning to speak French and Swedish fluently, tennis, swimming, ballet, horseback riding, guitar lessons, drama club, and pottery classes—seems over-the-top and like too much. If my daughter was experiencing any type of burnout, I'd immediately cut back on her weekly activities. But she genuinely loves doing all of these activities.

Importantly, my 11-year-old daughter doesn’t feel any pressure from me to be an overachiever or that her “worthiness of love and belonging” has anything to do with being a rock star on the playing field or getting straight A’s at school. (See "Flourishing in Life Does Not Require Getting Straight A's")

Because my dad put so much pressure on me and my sisters to be varsity athletes and get perfect grades, I make it very clear to my daughter that I don't share the same value system as her late grandfather. That said, she also knows that optimizing the functional connectivity between all four brain hemispheres and “unclamping” her prefrontal cortex is the best way to let her creative juices run wild, get in the flow zone, and achieve periodic states of superfluidity.

Hopefully, learning more about these concepts will inspire readers of all ages to structure daily routines that optimize the gray matter volume and interconnectivity of your four brain hemispheres along with the daily pursuit of experiencing moments of "absolutely zero friction, viscosity, or entropy between your thoughts, actions, and emotions."