"We've done nothing so far. The tip of the iceberg is genomics. The bottom of the iceberg is epigenetics."
- Professor Randy Jurtle.
Most people know that muscle cells grow with the physical stress of exercise. The greater the stress, the more the muscle cells grow - to a point. There is an optimal zone of physical stress, heavier than what the muscle cells can comfortably lift, but not so heavy so as to result in significant injury. This optimal zone of muscle growth and remodelling exists in a narrow region between physical capability (weight a person routinely lifts) and impossibility (weight far past their capabilities).
Neurons also grow with stress, but not physical stress; neurons respond to the experiential stress of new, challenging experiences. Whenever a person has an experience outside their comfort zone, they learn something new, during which new neuron projections or even new hippocampal neurons are created. Just like in muscle cells, there is an optimal zone for learning; the learning experience should be unfamiliar and therefore somewhat discomfiting, but not so foreign so as to result in utter confusion, or mental trauma. Like muscles, this optimal zone of brain growth and remodelling also exists in a narrow region between experiential familiarity (situations a person understands well) and confusion (situations way past their understanding).
Neurogenesis occurs in the human hippocampus throughout a person's life.
Thus, both muscle cells and neurons optimally grow and remodel when a person finds the edge, the place where you push yourself, the region between the order of routine and the chaos of taking things too far; in muscle cells it is physical, in neurons it is experiential. Finding a muscle's edge enhances a person's strength, but finding the brain's edge enhances a person's mind.
Enhances the memories that form you.
The Ancestral Hypothesis
In addition to new neurons projections and new neurons, neurons can be altered a third way, one that is not so much a process of creation as it is a process of revealing what is already there.
We all contain a genetic code, the entirety of our sequence of genes, within each of our nucleated cells. These genes provide a template for the expression of proteins, molecules that build the cells and ultimately, build us. The genetic code is fixed and cannot be altered; thus, many scientists believe that a person cannot escape the destiny of their genetic code. Yet this is not so, for in truth we can actually alter which genes remain dormant, or “locked,” and which ones become expressed, or “unlocked.”
The ancestral hypothesis states that our genetic code represents the cumulative biological potential of all the ancestors that preceded us. However, most of that genetic code remains locked in life, the genes never expressed, most of our ancestral biological potential never actualized. If we could unlock those genes, we could each realize our full potential as the current manifestation of a long line of ancestors. Yet the only way to unlock these genes is to challenge ourselves by seeking new experiences that lie between familiarity and confusion, experiences that call for new genes to reveal themselves, turning more of the potential you “on” so as to reveal aspects of "you" that you never knew existed.
We each have the capacity to unlock the biological potential of a long line of ancestors, but only if we confront new, challenging experiences.
The ancestral hypothesis posits that by seeking new, challenging experiences - seeking the edge - you can rescue your ancestors from obscurity. You rescue them, by partially becoming them. You rescue yourself, by becoming you. But not the “you” that exists right now.
The “you” that you could be.
By seeking the edge, we can potentially turn on numerous genes that are currently silenced (and perhaps turn off some that are currently overactive). Repeatedly, scientists tell us we are the sum of our genes (hence the pursuit of gene therapy for diseases), yet this is not so - it is more accurate to state that we are the sum of those genes that are expressed; many are not. The concept of differential gene expression is described by the scientific field of epigenetics.
In the 1940s, British biologist Conrad Hal Waddington introduced the concept of epigenetics, which literally means "above genetics." Strictly speaking, epigenetics describes heritable changes in gene expression, through processes such as DNA methylation and histone modification, that do not alter the structure of the genes themselves. Plainly speaking, this means that the same genetic code can be “read” in different ways by the body, simply by physically blocking genes so they cannot be expressed into proteins, or unblocking them so they can. Blocked genes remain “locked,” unable to express themselves, whereas unblocked genes are “unlocked,” able to contribute to the growth and remodelling of the cell, and ultimately the person.
If epigenetics sounds confusing, consider the novel The Count of Monte Cristo by French author Alexandre Dumas. The original 1844 story is set in stone. However, various film adaptations are made every one or two decades, the story brought to life by a different director and set of actors every time; each adaptation varies tremendously (watch the 1975 and 2002 versions; I leave it to you to decide which is better). Thus, how the story is told impacts how it is brought to life as much as - or more than - the story itself. Epigenetics states that although each person’s genetic code is set in stone, through varying and different experiences, that code can be brought to life in vastly different ways. Thus, how the code is read impacts how it is brought to life as much as - or more than - the code itself.
The original story of The Count of Monte Cristo is set in stone, yet each film adaptation varies tremendously. Likewise, a person's genetic code is also fixed, but can be brought to life in vastly different ways.