The Neuroscience of Superfluid Thinking

Cerebellum (Latin: “little brain”) in yellow. Cerebellar means “related to the cerebellum”. Cerebro-cerebellar circuits connect both hemispheres of the brain to the left and right cerebellar hemispheres.

Source: decade3d – anatomy online/Shutterstock

Until recently, the human cerebellum was viewed primarily as a brain region whose sole purpose was to coordinate motor movements; Most neuroscientists did not believe that the cerebellum supports non-motor cognitive functions. But around 1998, at the beginning of the 21st century, this purely motor view of the cerebellum began to change. Today, most neuroscientists agree that our so-called “little brain” plays a major role in cognition.

In this post, I will single out two articles from January 2022 that put the functional connectivity of the cerebellum and cerebellum in the spotlight through the lens of an “Up Brain Down Brain” model that my neuroscientist father and I created in the early 2000s.

The first paper (McAfee, Liu, Sillitoe & Heck, 2022) presents a new theory on how the cerebellum coordinates neuronal communication in the cerebral cortex. The second work (Li et al., 2022) examines how the cerebro-cerebellar connectivity between microzones of the cerebellum and specific regions of the cerebrum affects fluency in language tasks.

Cerebro-cerebellar circuits coordinate fluid movement

In the 1970s, when I was just starting out in tennis, Arthur Ashe and Bjorn Borg were my role models.

Borg was notorious for his cool (almost “icy”) Swedish temper and grace under pressure. Ashe was a trailblazer who famously said, “There’s a thing in sport called ‘paralysis by analysis.'” My neurosurgeon father who wrote The Weave of the Mind, filtered their playstyles through brain research.

When teaching me how to play Borg, Dad focused on hacking the vagus nerve, taking deep diaphragmatic inhales before each serve, followed by a long, slow exhale. This breathing technique activated my parasympathetic nervous system and suppressed fight-or-flight stress. When coaching me to play like Ashe, Dad focused on not “overthinking” by relaxing my cerebral cortex and relying on the memory of the cerebellar muscles.

    Photo and illustration by Chris Bergland (circa 2005)

This sagittal cerebro-cerebellar diagram illustrates Bergland’s split-brain model and was published in The Athlete’s Way.

Source: Photo and illustration by Chris Bergland (circa 2005)

I wrote in the mid 2000s The Athlete’s Way; and my father was the book’s medical advisor. From a neuroscientific perspective, our goal was to provide readers with a new split-brain model that will help them optimize flow states, experience superfluidity, and achieve peak performance.

Because the cerebellum has long been known to play a central role in the coordination of muscle movement, we hypothesized that athletes might improve the fluidity of their motor coordination by emphasizing the importance of bottom-up processing.

On the other hand, too much top-down cerebral processing would disrupt the flow and likely result in an overthinking athlete choking from “analysis paralysis.”

Notably, the cerebrum (“big brain”) has two cerebral hemispheres and the cerebellum (“little brain”) has two cerebral hemispheres. In coordinating fluid movement, the right cerebellum and left brain work together to coordinate motor skills on the right side of the body and vice versa.

The criss-cross functional connectivity of “up brain-down brain” is key to creating super fluidity in sports. Interestingly, left-brain thinking also benefits from robust connectivity with the right cerebellar hemisphere, and whole-brain thinking benefits from having all four cerebral hemispheres working in sync.

For example, in right-handed individuals, who tend to have most of their language functions in the left hemisphere, microzones in the right hemisphere of the cerebellum coordinate language tasks (Li et al., 2022). For language tasks involving the left brain, regions in the right cerebellum (eg, lobule VI, crus I, and crus II) are activated as part of a cerebro-cerebellar loop.

Cerebro-cerebellar circuits can coordinate superfluid cognitive processes

As an athlete, my interest in optimizing the functional connectivity of all four hemispheres of the brain was directly related to improving my athletic performance by enabling perfectly coordinated smooth flow (i.e., superfluidity).

As a writer, I realized that whenever I experienced a state of flow while typing more than 100 words per minute using the cerebellar muscle memory I learned in a high school writing class, my thinking felt also super fluid.

Anecdotally, as a retired ultramarathoner who still enjoys jogging, I’ve found cardio to benefit my creative thinking and writing process. Fresh ideas seem to spring from my subconscious when I’m jogging, and it’s much easier to connect the dots between seemingly unrelated ideas while engaging in moderate to vigorous physical activity.

One day in 2009, walking home from the gym, I met an old friend named Maria who is a poet and also just finished a workout. We began discussing how cardio seemed to improve our ability to develop language. She said, “Whenever I’m on the elliptical trainer, poetry oozes out of me,” while flexing her arms and legs on two legs.

As Maria mimicked the back-and-forth movements on an elliptical trainer, I instantly imagined a bi-directional feedback loop between all four brain hemispheres, creating a cerebro-cerebellar loop that looks like an 8. And I imagined what this circuit could look like to ease speech flow. I rushed home and drew a rudimentary “Super Eight” brain map (below).

    Photo and illustration by Chris Bergland (circa 2009)

This brain map illustrates how robust cerebro-cerebellar connectivity could facilitate superfluidity during exercise and during the writing process.

Source: Photo and illustration by Chris Bergland (circa 2009)

Without explicitly referring to neuroscience, Joyce Carol Oates has vividly described how some prose captures the “fluidity of movement” and how throughout her writing career, daily jogging has helped her “maintain a consistent, fluid voice.” when she writes a novel.

In a 1999 play for the new york times’ Art department, “To Invigorate Literary Minds, Start Moving Literary Feet,” Oates explains how running expands her awareness and allows her to “imagine what I’m writing as a movie or a dream.” She goes on to say:

When running, the mind flies with the body; the mysterious blossoming of language seems to pulse in the brain, in rhythm with our feet and the swinging of our arms. For example, the structural issues I set myself writing on a long, crushing, frustrating, and sometimes desperate morning at work I can usually unravel by running in the afternoon.

Cerebellar dysfunction can cause uncoordinated thinking

Jeremy Schmahmanns dysmetry of thought The hypothesis states that a well-functioning cerebellum can coordinate thoughts in a similar way to movements.

Conversely, a dysfunctional cerebellum can cause uncoordinated movements or, in some cases, confused thinking. Schmahmann is a neurologist and specialist in cerebellar ataxia am mass. Harvard Medical School General Hospital. ataxia means “lack of coordination” in Greek.

In the late 20th century, Schmahmann noticed that some patients with damage to specific microzones of the cerebellum did not show physical ataxia but appeared to have trouble coordinating their thoughts.

In 1998, Schmahmann coined the term “dysmetry of thinking”. In the same year he published a seminal paper in which he described cerebellar cognitive affective syndrome (CCAS). At the time, it was a radical notion to speculate that the cerebellum was involved in non-motor functions such as cognition.

Fast forward to 2022. We now have mounting evidence that the cerebellum plays an important role in coordinating cognitive processes.

McAfee, Liu, Sillitoe and Heck/Creative Commons Attribution License (CC BY)

Figure 1. (A) Cerebro-cerebellar interaction via reciprocal connections between specific cerebral and cerebellar areas. (B) Cerebellar modulation of communication between cerebral cortical areas. Here the cerebellum coordinates communication by increasing the coherence of neuronal oscillations in a task-specific manner.

Credit: McAfee, Liu, Sillitoe, and Heck/Creative Commons Attribution License (CC BY)

In their January 2022 open access article “Cerebellar Coordination of Neuronal Communication in Cerebral Cortex,” first author Samuel McAfee et al. explain how the cerebellum coordinates and optimizes cerebral cortical communication during cognitive processes, similar to how it optimizes motor coordination. Their representation in Figure 1 (above) shows these cerebro-cerebellar functions in action.

Going forward, we need more research to better understand how cerebro-cerebellar connectivity coordinates fluid thinking.

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