Primitive Brain Area Linked to Human Intelligence
Frontal lobes are not the sole seat of human intelligence.
Posted May 14, 2013
Researchers have discovered that the size of our frontal lobes alone does not account for the superior cognitive abilities of humans. In a study released on May 13, 2013 in the Proceedings of the National Academy of Sciences researchers suggest that more 'primitive' areas of the brain – such as the cerebellum – were equally important in the expansion of human intelligence.
The frontal lobes are located at the front of each cerebral hemisphere, and are thought to be critical for advanced intelligence. It has long been assumed that the growth of the frontal lobes in humans was disproportionate and what seemed like explosive evolutionary growth was correlated to increased intelligence in homo sapiens. New research is questioning this hypothesis.
Lead author Professor Robert Barton from the Department of Anthropology at Durham University states, "Probably the most widespread assumption about how the human brain evolved is that size increase was concentrated in the frontal lobes. It has been thought that frontal lobe expansion was particularly crucial to the development of modern human behavior, thought and language, and that it is our bulging frontal lobes that truly make us human. We show that this is untrue: human frontal lobes are exactly the size expected for a non-human brain scaled up to human size.”
The Underestimated Power of the Cerebellum
In 1504, Leonardo da Vinci made wax castings of the brain and coined the term ‘cerebellum’ which is Latin for “little brain.” My father was a neuroscientist who was fascinated by the powerful and mysterious cerebellum. He believed that the cerebellum worked in conjunction with all other parts of the brain to influence cognition and human intelligence. At the time there was little scientific evidence to support his educated guess that the cerebellum was involved in cognition.
The cerebellum is only 10% of brain volume but holds over 50% of your brain’s total neurons. My father always said: “Whatever the cerebellum is doing, it’s doing a lot of it.” The cerebellum is responsible for fine-tuned muscle movements, balance, proprioception, implicit memories and ‘street smarts.’ But it remains very mysterious to neuroscientists. HM, the famous brain patient who had his entire hippocampus removed in a botched attempt to treat epilepsy, suffered complete amnesia and could not form any declarative memories. However, with a cerebellum in tact he was able to learn puzzles and retain ‘cerebellar’ procedural memories he had absolutely no cerebral recognition of learning.
In the 1970s, my father, Richard Bergland, was the lead neuroscientist consulted for the international bestseller “Drawing on the Right Side of the Brain.” My father is quoted in the book saying, “You have two brains: a left and a right. Modern brain scientists now know that your left brain is your verbal and rational brain; it thinks serially and reduces its thoughts to numbers, letters and words… Your right brain is your nonverbal and intuitive brain; it thinks in patterns, or pictures, composed of ‘whole things,’ and does not comprehend reductions, either numbers, letters, or words.” This philosophy became the basis for Betty Edwards’ theory about creativity, specifically about succeeding in visual art.
Later in his life, my father became an advocate for a different split-brain model between the cerebrum and the cerebellum. Because the Latin phrases of “cerebrum” and “cerebellum” don’t connote a split-brain model, I coined the phrases “up brain” and “down brain” through conversations with my father and first published these terms in The Athlete’s Way to offer an easy visual and simple point of reference for readers. Although this terminology might sound grammatically incorrect, it is a direct and cogent response to the phrasing of “left brain” and “right brain.”
By the end of his lifetime my dad was convinced that the salient divide in the brain was north-south between the up brain and the down brain, not just east-west. The up brain-down brain divide was more intriguing to him than left brain-right-brain and he passed this curiosity on to me.
When you practice anything to create a non-thinking state of automatic muscle memory, these implicit memories are stored in the Purkinje cells of the cerebellum. As an athlete, I have always focused on rigorous cerebellar training to hard wire muscle memory. As a writer, I have had to flex more cerebral muscle and the use of language from the left hemisphere while connecting ideas using right hemisphere creativity. I have spent the past decade researching and analyzing the neuroscientific and empirical evidence of how our brain hemispheres interact. It is exciting to see cutting edge research in May of 2013 confirm that the cerebellum may be strongly linked to human cognition.
Neuroscientist Antonio Damasio has written extensively on his theory that the brainstem may be the seat of human consciousness. In my split brain model the ‘midbrain’ literally divides the up brain from the down brain. The brainstem is ultimately the spark plug and central axis that connects the body to all hemispheres of the brain. It channels information in both directions as the hub that is the midway between the Vermis (which divides the hemispheres of the cerebellum) and Corpus Callosum (which creates communication between the cerebral hemispheres) and connects to the spinal cord and the central nervous system.
In The Athlete’s Way (St. Martin’s Press) I hypothesize that the cerebellum may be the seat of the unconscious mind. Freud put the unconscious mind under the surface in an iceberg metaphor which resembles the split-brain divide between up brain and down brain. Scientists have known for years that the cerebellum holds implicit and procedural memories. Exactly how the implicit knowledge of the cerebellum interacts with the explicit and declarative memories of the cerebrum to create human intelligence is a fascinating area that needs more research.
Robert Barton concludes, "This means that areas traditionally considered to be more primitive were just as important during our evolution. These other areas should now get more attention. In fact there is already some evidence that damage to the cerebellum, for example, is a factor in disorders such as autism and dyslexia."
The scientists argue that many of our high-level cognitive functions are the result of extensive brain networks linking many different areas of the brain. They suggest it may be the structure of these extended networks working in concert more than the size of any isolated brain region that is critical for our superior intelligence.