What is a Human Brain? Part I

Brain-imageSo one of the most interesting things about the human brain is that unlike other organs of the human bodies of our earliest known ancestors, the human brain has significantly changed not once but three times. And that, believes neuroscientist Suzana Herculano-Houzel at the Federal University of Rio de  Janeiro, is because our species developed a unique technology: The cooking fire.

As David Fox, quoting her in an article entitled The Limits of Human Intelligence, in the 2015 Special Collector’s Edition of Scientific American, writes it all seems to come down to calories:

Animals can spend only so many hours eating per day. Primates thus faced a critical trade-off  as they evolved larger brains … they could expend their limited calories on a larger, more powerful body ~ or on a smarter brain. Gorillas, orangutans and chimpanzees maxed out their calories with various combinations of big strong bodies and brains containing 20 to 40 million billion neurons. Those brains consume around 9 percent of the total calories that they burn ~ which means that they must spend up to eight hours a day foraging.

Humans, in contrast, sport brains with 86 billion neurons ~ and we devote a whopping 20 percent of our calories to feeding our heads …. newborns use an astounding 65 percent.

Fox continues:

Around 1.5 million years ago our ancestors began to use fire to transform food…. Cooking makes it easier to digest plant foods and to extract calorie-dense fat from animal carcases ~ for example by stewing bones to extract marrow. It seems an unlikely co-incidence that around the  time our human ancestors conquered fire they also finally final broke through the  caloric barrier and jumped from brains of perhaps 40 billion brain neurons (Homo habilis) to 60 billion neurons (Homo erectus) and finally to 86 billion. Were it not for cooking, she says, ” we would not be here.”  And brain size does matter in terms of smartness/intelligence.

As he shows on a logarithmic map where brain mass is not a fixed percentage in all species but, instead,  is three quarters of the body mass, humans beat this “power law” by a factor of 7.5 which is the best of any species, dolphins are next. Elephants, dogs, and horses, for example, conform to this law, while the whales fall below as  do hippopotamuses and pigs. Said differently, that number reflects the amount of neural reserve available to intelligence after the brain takes care of everyday house keeping activities.

So that is one side of the story. The other relates to the “wiring” inside the brain  because as it got larger there developed areas of specialized functions to solve the connectivity problems between neurons depending on the distance their axons have to travel to form a synapsis with another cell. And that raises issues regarding the thickness of axons etc. But that road of detailed scientific anatomy is not the one I want to go down now because, for me, the far more important story relates to the fact that for centuries, the common wisdom, as Norman Doidge M.D. writes in the Preface to his book, The Brain That Changes Itself (Viking Penguin, New York, 2007) was that after childhood the brain changed only when it began the long process of decline; that when brain cells failed to develop properly, or were injured or died they could not be replaced. nor could the brain ever alter its structure and find a new way to function if part of it was damaged….

He continues:

The belief that the brain could not change had three major sources: the fact that brain damaged patients could so rarely make full recoveries; our inability to observe the living brain’s microscopic activities; and the idea ~ dating back to the beginnings of modern science ~ that the brain is like a glorious machine. And while machines do many extraordinary things they do not change and grow…. Often…[when patients did not progress psychologically as much as hoped] .. the conventional wisdom was that their problems were deeply “hardwired” into an unchangeable brain. “Hardwiring” was another machine metaphor coming from the idea of the brain as computer hardware, with permanently connected circuits, each designed to perform a specific, unchangeable function.

Now, thanks to the extensive research of an American man, of German stock, named Michael Merzenich who, after many experiments, and objections from some of his peers, finally had the courage to use the word plasticity, without inverted commas, in a scientific journal. And thus, it was , thanks to his work over a period of some thirty years that the concept of neuroplasticity ~ of the brain’s ability to change itself ~ has been accepted by mainstream science.

Fox ends his Preface this way:

The neuroplastic revolution has implications for, among other things , our understanding of how love, sex, grief, relationships, learning, addictions, culture, technology and psychotherapies change our brains. All of the humanities, social sciences and physical sciences, insofar as they deal with human nature are affected as are all forms of training….

While the human brain has apparently underestimated itself, neuroplasticity isn’t all good news; it renders our brains more vulnerable to outside influences. Neuroplasticity has the power to produce more flexible but also more rigid behaviours ~ a phenomenon I call the “plastic paradox”. Ironically, some of our most stubborn habits and disorders are products of our plasticity. Once a particular plastic change occurs in the brain and becomes well established, …[as a result of a process known as “neurons that fire together , wire together”. And thus thicken the size of the axon pathways in the same way that a too heavy needle playing an LP record would deepen the grove, thus leading to the term “ingrained” habits] … it can prevent other changes from occurring.

And that leads me to the work of a chiropractor named D. Joe Dispenza who had written extensively on that subject. His first book was entitled Evolve Your Brain: The Science of Changing Your Mind,  which he followed up with a later one, Breaking the Habit of Being Yourself: How to lose your mind and Create a New One ( Hay House, Carlsbad, Ca, 2013) from which the following quotes are taken:

The purpose … [of this book] … is to build a realistic working model of personal transformation that will help you understand how we can change … and how mind affects matter.

When you and I can connect the dots of what science is discovering about the nature of reality, and when we give ourselves permission to apply those principles in our day-to-day existence, then each of us becomes both a mystic and a scientist in our own life.

We should never wait for science to give us permission to do the uncommon; if we do then we are turning science into another religion. We should be brave enough to contemplate our lives, do what we thought was “outside the box” and do it repeatedly. When we do that, we are on our way to a greater level of personal power.

….What I mean is that if you make the effort to change your inner world of thoughts and feelings, your external environment should begin to give you feedback to show you that your mind has had an effect on your “outer” world. Why else would you do it?

for true change to occur it is essential to “unmemorize” an emotion that has become part of your personality   to move out of the past … and then to recondition the body to a new mind…. [So] … to change your personality, you need to change your state of being, which is intimately connected to feelings that you have memorized. Just as negative feelings can become embedded in the operating system of your subconscious, so can positive ones.

At one time or another, we’ve all consciously declared: I want to be happy. But until the body is instructed otherwise, it’s going to continue expressing those programmes of guilt or sadness or anxiety. The conscious, intellectual mind may reason that it wants joy, but the body has been programmed to feel otherwise for years. We stand on a soapbox proclaiming change to be in our best interests, but on a visceral level  we can’t seem to bring up the feeling of true happiness. That’s because mind and body aren’t working together. The conscious mind wants one thing, but the body wants another….. [Consequently]  …. When the mind and the body are in opposition, change will never happen.  ( All emphases in the original).