Radical New Discoveries Are Turning Neuroscience Upside Down

New brain research puts underestimated subcortical influences in the spotlight.

Posted Jan 12, 2017

Viking Press
As illustrated by the cover of his book "The Fabric of Mind," my father (Richard Bergland, M.D.) always preferred sagittal cross sections of the brain because this vantage point best illustrates the divide between cortical and subcortical structures. 
Source: Viking Press

Advances in neurotechnologies are shattering long-held belief systems and turning well-established views of how the brain works upside down. These are exciting times of radical neuroscientific discovery that help us better understand how our minds and brains work.

In recent months, a groundswell of new research on subcortical brain regions—including the cerebellum, brainstem, and basal ganglia—are changing the way neuroscientists view the function of cortical brain regions that include the prefrontal cortex. (Cortical means “relating to the outer layer of the cerebrum” which is known as the cerebral cortex. Subcortical refers to any brain regions below the cerebral cortex.)

Cortical brain regions of the brain are typically considered the “thinking cap” that encompasses all of the cerebral regions in the brain. On the flip side, subcortical regions are considered “non-thinking” regions of the brain that are driven by automatic or subconscious forces. 

Later in this Psychology Today blog post, I'm going to sum up the highlights of three different state-of-the-art studies on subcortical brain structures that were published in the past year. But first, I want to give you some personal background that explains why I've had my antennae up for this type of research since the beginning of the 21st century. And why I wake up every morning hoping for new cutting-edge research on subcortical brain regions.

"Whatever the Cerebellum Is Doing, It's Doing a Lot of It"

Courtesy of Larry Vandervert
Source: Courtesy of Larry Vandervert

My father, Richard Bergland, was a neurosurgeon, neuroscientist, and author of The Fabric of Mind. As a visionary thinker, my dad was a trailblazer and pioneer who was ahead of his time. As a neuroscientist, my father often grew frustrated by the technological limitations of the 20th century.

All too often, it was scientifically impossible for my father to empirically prove one of his hypotheses about the role of a particular brain region—that he gained by observing his human patients before and after performing brain surgery in the operating room—using animals such as mice or sheep in his laboratory.

For example, a stroke or tumor that ultimately affects someone’s cognitive, emotional, and psychological function could occur in cortical regions of the cerebrum that include the frontal, parietal, temporal and occipital lobes or subcortical structures that include the basal ganglia, brainstem, and cerebellum.

As a neurosurgeon, my father witnessed first hand very specific neurological consequences that a traumatic brain event in one of his patients would cause. My dad knew anecdotally from decades of performing brain surgery that both cortical and subcortical damage had dramatic impacts on various aspects of cognitive and psychological function. But, again, he couldn't prove these findings empirically in his laboratory.

Because of his anatomical knowledge that the cerebellum was only 10 percent of brain volume but held well over 50 percent of the brain’s total neurons my father would regularly raise the question of subcortical influences by saying, “We don’t know exactly what the cerebellum is doing. But whatever it’s doing, it’s doing a lot of it.”

In the late-twentieth-century, my father had a tough time convincing any of his scientific peers that ‘non-thinking’ subcortical regions in the brain (such as the cerebellum) could influence cognitive processes. But as I mentioned above, it was impossible for him to prove what he observed anecdotally with patients in an empirically-based animal study.

Sadly, most of my father's colleagues in the medical establishment eventually labeled him a heretic for relentlessly attempting to put the cognitive and emotional influences of the cerebellum and other subcortical brain regions in the spotlight.

My dad’s colossal disappointment about being unable to get his most radical ideas about how the brain works published in peer-reviewed journals made me feel bad for him. I wanted to help my dad find a stealth away around what he called 'gatekeepers of the Ivory Tower' by coming up with a way to bypass the medical establishment and get his revolutionary ideas about the brain published. 

Luckily, in 2004, after I broke a Guinness World Record by running 6 back-to-back marathons (153.76 miles) in 24 hours on a treadmill, a literary agent in New York named Giles Anderson approached me to see if I was interested in writing a book. A few weeks later, we had signed a deal with Diane Reverand at St. Martin’s Press. I knew this was a golden opportunity and my once-in-a-lifetime chance to bring my father’s ideas about subcortical brain structures to a large general audience.

Throughout 2005, my father and I spoke a few times a day and exchanged hundreds and hundreds of emails about neuroscience. During this period, my dad and I created the "Bergland Split-Brain Model" that seated cortical structures in what we called the "up brain" and subcortical structures in what we referred to as "down brain."

The Bergland split-brain model of “up brain-down brain” was a direct and cogent response to the ubiquitous but deeply flawed “left brain-right brain” model.

In early 2007—just a few weeks before my father died suddenly of a heart attack—I published our revolutionary split-brain framework in The Athlete's Way: Sweat and the Biology of Bliss. (I am eternally grateful that my father died knowing that his radical ideas about subcortical brain regions had been published by St. Martin's Press). 

The illustration of the “Bergland Split-Brain Model” below is from p. 81 of The Athlete’s Way. This diagram highlights the salient divide between cortical and subcortical brain regions in a streamlined hypothetical framework that relies on the yin-yang of robust functional connectivity between these regions to maintain psychological homeostasis.

Screenshot by Christopher Bergland
This illustration of the "Bergland Split-Brain Model" was created in 2005 by Christopher Bergland in conjunction with his father, Richard Bergland, M.D., and published on p. 81 of The Athlete's Way (St. Martin's Press).
Source: Screenshot by Christopher Bergland

"Up Brain-Down Brain" | Version 2.0

My original version of "up brain-down brain" as seen above focused solely on the cerebrum (Latin for "brain") and the cerebellum (Latin for "little brain"). However, based on all of the new groundbreaking research about the powerful influence of other subcortical brain regions in recent years; I would now include the basal ganglia and brainstem as part of the "down brain" in the updated 2.0 version of the Bergland split-brain model.

A decade ago, when I published my father’s radical ideas about subcortical brain structures in The Athlete’s Way, most of these ideas were still just an educated guess based on my dad's anecdotal evidence. Since then, advances in neuroscience-based technologies have made it possible for researchers to dig deeper and unearth exciting new clues about the mysterious interplay between cortical and subcortical brain regions in laboratories around the globe. 

The latest empirical findings are turning conventional wisdom about how ‘non-thinking’ subcortical regions of our brain actually affect cerebral ‘thinking’ upside down.

Because there is way too much new scientific research on subcortical brain structures to present in a single blog post, I’ve decided to cherry pick three groundbreaking studies that were published in the last year. Each of these studies helps to advance our understanding of how the cerebellum, brainstem, and basal ganglia work in conjunction with cortical regions of the brain.

In the section below, I’ve included one example for each of these three brain regions along with an artistic representation of the brain region, a synopsis of the study, and a link to a more in-depth Psychology Today blog post about the research.

1. The Cerebellum

CLIPAREA l Custom media/Shutterstock
The cerebellum. 
Source: CLIPAREA l Custom media/Shutterstock

In 1504, Leonardo da Vinci made wax castings of the human brain and coined the term "cerebellum" to describe two small brain hemispheres that are neatly tucked under the relatively humungous hemispheres of the cerebrum. Cerebellar is the sister word to cerebral and means ‘relating to or located in the cerebellum.'

Historically, neuroscientists considered the cerebellum to be the seat of non-thinking activities such as coordinating and fine-tuning muscle movements. However, in recent years, a wide range of studies have shown (for the first time) that the cerebellum plays an important role in many of our cognitive, emotional, and creative processes.

For example, neuroscientists and psychologists at Stanford University are conducting groundbreaking research on the neural basis of optimizing creative capacitiy. Their findings suggest that the cerebellum may be the prime driving force in many of our creative processes. The research suggests that in order for creative thinking to run free, it's helpful to 'unclamp' the rigid executive functions of the prefrontal cortex. 

The Stanford researchers have found that suppressing the executive-control centers of the cerebrum—and allowing the cerebellum to be the “controller"—increases spontaneous creative capacity. This is a revolutionary concept that challenges the dubious construct of the “right brain” being our creative epicenter. 

The June 2016 study, “Changes in Brain Activation Associated with Spontaneous Improvization and Figural Creativity After Design-Thinking-Based Training: A Longitudinal fMRI Study,” was published in the journal Cerebral Cortex. I wrote about this research in a Psychology Today blog post, "Enhanced Cerebellum Capacity Boosts Creative Capacity."

2. The Basal Ganglia 

CLIPAREA l Custom media/Shutterstock
The basal ganglia. 
Source: CLIPAREA l Custom media/Shutterstock

The basal ganglia is a subcortical brain region with neural projections and functional connectivity that extend to the cerebral cortex, brainstem, cerebellum, and several other brain areas.

The striatum is a specific subsection of the basal ganglia that contains a cluster of various brain regions and neurons that are associated with habit formation, control of voluntary movements, emotions, and addiction.

According to Massachusetts Institute of Technology (MIT) neuroscientists, malfunctions of the basal ganglia have been associated with Parkinson’s and Huntington’s diseases, as well as autism spectrum disorders (ASD), obsessive-compulsive disorder (OCD), and Tourette’s syndrome.

Using a mouse model, MIT neuroscientists led by Ann Graybiel were recently able to identify that a specific cluster of neurons in the basal ganglia is involved in making emotional decisions that require any type of anxiety-provoking "cost-benefit analysis" that entails being pragmatic while listening to your primal gut instincts simultaneously. 

The MIT researchers have identified that the neural communication pathway to the striatum is directly linked to another complex subsystem that is fueled by dopamine. The researchers call this subsystem a “striosome-dendron bouquet.”

Please take a few minutes to watch Graybiel clearly sum up how subcortical regions like the basal ganglia interact with the "thinking cap" of the cerebral cortex. I had an Aha! moment after watching this YouTube clip. The video is really well done and has terrific visuals.The latest MIT research on the striatum shows that the brain mechanics of emotional decision making involve a loop–circuit that relies on the function of dopamine that is rooted in the basal ganglia. 

This September 2016 study, "Striosome–Dendron Bouquets Highlight a Unique Striatonigral Circuit Targeting Dopamine-Containing Neurons,” was published in Proceedings of the National Academy of Sciences. I wrote a Psychology Today blog post based on these findings, "Study Pinpoints Brain Circuitry of Emotional Decision Making." 

3. The Brainstem

CLIPAREA l Custom media/Shutterstock
The brainstem. 
Source: CLIPAREA l Custom media/Shutterstock

The brainstem is a subcortical brain region that is pivotal for maintaining consciousness, regulating automatic cardiac and respiratory function of the central nervous system, and much, much more.

Until recently, neuroscientists didn't think the brainstem played a role in mammalian social behaviors. But new research shows that neural projections from the prefrontal cortex to a specific region of the brainstem are directly linked to controlling impulsive behavior as well as the "fight-or-flight" response. 

In 2007, Dean Mobbs, professor of cognitive neuroscience at Caltech and his team, identified for the first time that the interplay between the prefrontal cortex (PFC) and the periaqueductal gray (PAG) area of the brainstem was associated with specific aspects of social behavior—such as the urge to take flight in response to a threatening stimuli, such as a predator or bully. 

For this study, Mobbs et al. used fMRI to monitor brain activity while study participants played a Pac-Man-like game inside the neuroimaging scanner. The researchers found that in the moments just before someone's Pac-Man avatar was gobbled up, the players' prefrontal cortex would shut down just as a region of the brainstem called the PAG would become very active and light up in the fMRI.

 EMBL/Livia Marrone
The prefrontal cortex (PFC) connects directly to a region of the brainstem—the Periaqueductal Gray (PAG)—through specific prefrontal cortical neurons. These neurons (in purple) project directly from the prefrontal cortex to the PAG and appear to control instinctive behaviors.
Source: EMBL/Livia Marrone

Earlier this week, neuroscientists from the European Molecular Biology Laboratory (EMBL) in Italy pinpointed specific neuronal projections from the prefrontal cortex to the PAG region of the brainstem that appear to prevent sociable creatures—such as humans and mice—from acting out on impulsive instincts driven by feelings of social defeat.

The January 2017 study, ”Prefrontal Cortical Control of a Brainstem Social Behavior Circuit,“ was published online ahead of print in Nature Neuroscience. I wrote about these findings in a Psychology Today blog post, "Social Defeat Wreaks Havoc on Brain Circuitry, Study Finds."

This EMBL study illuminates the importance of robust functional connectivity between the prefrontal cortex and the brainstem for controlling fear-based impulsivity triggered by social defeat or bullying. These findings could have broad implications for treating schizophrenia along with a wide range of mood disorders such as depression, anxiety, and avoidance behaviors associated with post-traumatic stress disorder (PTSD).

Donald Trump is a perfect real-world example and case study of the new EMBL findings that impulse control requires robust functional connectivity between the PFC and PAG. For example, as I was watching Donald Trump lose his cool in a press conference yesterday and lash out at a CNN reporter because he was feeling socially defeated and bullied by “fake news” allegations from anonymous sources... I wondered if our President-elect and his transition team might benefit from understanding the neural correlates of certain social behaviors? 

Staying even-keeled during emotional times of social defeat—when impulsivity or fear often leads to impulsive knee-jerk reactions of choosing fight-or-flight appears to require robust connectivity with the prefrontal cortex to maintain self-control and equanimity.

The good news is that these neural circuits are never fixed. Neuroplasticity makes it possible for each of us to improve the functional connectivity of our brains and learn to be more compassionate, empathetic, and avoid outbursts of aggression or rage. (To learn more about how to do this, check out my Psychology Today blog post, "5 Science-Based Ways to Break the Cycle of Rage Attacks")

Hopefully, the latest EMBL findings along with other breakthroughs presented herein that advance our understanding of the powerful influence subcortical brain regions have on our behavior will lead to fresh neuroscience-based interventions that improve individual lives and social dynamics between people from all walks of life. 

References

Manish Saggar, Eve-Marie Quintin, Nicholas T. Bott, Eliza Kienitz, Yin-hsuan Chien, Daniel W-C. Hong, Ning Liu, Adam Royalty, Grace Hawthorne, and Allan L. Reiss. Changes in Brain Activation Associated with Spontaneous Improvization and Figural Creativity After Design-Thinking-Based Training: A Longitudinal fMRI Study Cereb Cortex 2016. DOI: 10.1093/cercor/bhw171

Jill R. Crittenden, Paul W. Tillberg, Michael H. Riad, Yasuyuki Shima, Charles R. Gerfen, Jeffrey Curry, David E. Housman, Sacha B. Nelson, Edward S. Boyden,  and Ann M. Graybiel. Striosome–dendron bouquets highlight a unique striatonigral circuit targeting dopamine-containing neurons. PNAS 2016 113 (40) 11318-11323; published ahead of print September 19, 2016, DOI: 10.1073/pnas.1613337113

When Fear Is Near: Threat Imminence Elicits Prefrontal-Periaqueductal Gray Shifts in Humans. Dean Mobbs, et al. Science 317, 1079 (2007); DOI: 10.1126/science.1144298 

Tamara B Franklin, Bianca A Silva, Zina Perova, Livia Marrone, Maria E Masferrer, Yang Zhan, Angie Kaplan, Louise Greetham, Violaine Verrechia, Andreas Halman, Sara Pagella, Alexei L Vyssotski, Anna Illarionova, Valery Grinevich, Tiago Branco, Cornelius T Gross. Prefrontal cortical control of a brainstem social behavior circuit. Nature Neuroscience, 2017; DOI: 10.1038/nn.4470