A Sustainable Point of View

Depression, Part I: A Brain For All Occasions

Depression, Part I: A Brain For All Occasions

What IS depression?

When framing depression as a “mental illness,” we tell a certain kind of story, one that primes us to think along familiar lines of family histories and chemical imbalances. This is a story where suffering starts from the inside out to become the central story of someone’s life; it is a story of depression as a force of nature without meaning or justification, something that must be baked in at the level of the genes or the brain to make sense. Because depression is a disorder; a disease. After all, this is the only explanation we have for why perfectly normal and intelligent people could succumb to a feeling that the world is bleak and that people are hopeless. Right?

If hopelessness is “abnormal,” we might expect “normal” brains to be free to navigate life without the effects of hopelessness and disillusionment. Such “strong” brains would deftly weave through societies full of ingroup tribalism, systemic injustice, hidden agendas, and economic pecking orders with ease, avoiding the imprinting of suffering, hopelessness, loneliness, grief, injustice, powerlessness, invisibility, disillusionment, rejection or alienation. And if these armor-plated organs are indeed the norm, most of us should be able to stare directly into the face of poverty and inequality, racism and tyranny, slavery and war as light fare. Depressed brains, though – they feel all these things. Because something is wrong with them.

Of course, you could argue that to an indifferent cosmos, none of the above litany of terrible things really matters – they are just things that happen. But to us human beings, who feel our way through our environment, these things matter very much. Our brain interacts with the world itself by design, a world that can be genuinely bleak and hopeless to many. How should a normal brain feel under those circumstances?

Could a normal brain process an unforgiving world, even at a distance, to become biochemically depressed?  

The Mind is the Brain

Scientific paper after paper subscribes to the assumption that depression has to start in the brain, because it is characterized by dysregulated neurotransmitter systems that affect dopamine and serotonin, raise inflammation, lower neurotrophic growth factor and can be influenced by genetics. And that’s all true. You don’t have to deny any of that data to argue that the psychiatric model of depression is limited, because the problem is not one of facts, but interpretation.

The decades old dogma that the brain is controlled by genes and genes alone is just bad biology.

A mind feeling its way through the world is a mind embodied in a brain. Mind is a property of brain. When our emotions fire, at a whole other level it is being expressed in the neurotransmitter action of our limbic system. The feelings aroused in us by society, culture, politics, economics, existence and more, are feelings expressed in the medium of our neurobiology, in ways few in the mental health field have done much digging into.

This is a brain different from the one we’ve pictured for decades—a static, unchanging organ that is somehow separate from who we are. But we now know the brain to be a deeply plastic organ, designed to change as surely as our mind and environment do: from the way new information becomes wired into the structure of the brain’s connections, to how the brain changes our feelings in response to our shifting circumstance. That mind is a property of brain means that changing one is to change the other, for better and worse.

Representation: The Changing, Imaginative Brain

To understand how the world depresses people, we have to understand how the world gets inside.

The brain is designed to be neuroplastic.1 It is adaptable, meaning that it rewires itself not under special conditions, but as a matter of course. It needs to be this flexible, as humans are one of the few creatures who can transcend a particular niche to live everywhere from the hottest equatorial deserts to the most frigid arctic climes; from the silent vacuum of space to silent pressures of the deepest oceans. To make this possible, we need a brain that can map very different environments, including different ways of relating to them.

Because our unique survivability is tied to our cognitive flexibility, primates (including humans) evolved an entirely new biological invention called the neocortex. We wrapped our reptile brain (fight-flight-freeze) and the mammalian brain (limbic system/emotion) with this third brain,2 whose name means “new shell.” The neocortex is a pattern-recognizer and organizer that is insanely flexible, drinking in patterns learned through experience. This happens automatically as the brain converts all sensory information into two kinds of patterns—spatial patterns and temporal patterns (patterns across space versus time).3 Probably with the invention of language and syntax,4 the brain became hierarchically-organized, allowing humans to arrange how the spatial and temporal patterns fit together in an evolving model of the world stored in memory.

The neuroplastic neocortex runs an adaptable simulation of our environment, an evolving re-presentation (or representation) of the world that updates in memory. This rough story of its evolution outlines how human beings came to internalize the world, and how we created mind as an intermediary through which the world can shape how we think and feel.

Prediction: The Anticipatory Brain

Representational brains allow human beings a mild superpower few are familiar with: a limited ability to predict the future.5 The environment triggers constructs in our mind, and any relevant temporal patterns along with. For instance, seeing a dog might make us anticipate friendly hand-licking, while seeing a tiger might make us anticipate a less-friendly mauling, both inspiring an almost instant decision on how to act. This happens constantly, the brain matching incoming experience against a backlog of memory and stories, not just to understand what’s happening in the moment, but to try to predict what will happen next.6

These predictions aren’t byproducts of the brain’s functions, they are central to them. These predictions control very important biochemistry and behavior.7

Predictions occur in the subconscious, where a huge amount of processing happens way in advance of conscious thought. People execute a steady stream of thousands of automatic predictions each day, allowing them to do everything from predict the next notes of a song from the first, to finishing someone’s sentence for them, to driving on autopilot along routes we’ve driven a thousand times before.

When we predict something good in our future, something with value, it triggers the activity of dopamine neurons, motivating us to pursue that reward. This makes us goal-directed: we chase the proverbial carrot even when it is suspended only in the mind’s eye. Alternatively, when something defies our expectations, it becomes a prediction error, although this too is met with an increase in the firing of dopamine neurons. Why would the brain reward errors? Because A) this brings the process to consciousness to learn from it, improving future predictions; and B) making novel information rewarding incentivizes the search for new learning opportunities, a drive we call curiosity.

That our brain is always oriented to the future is both a blessing and a curse. A predictive brain that controls our biochemistry means that our subconscious speculation about our future will shape how we feel in the present, ongoing. How we feel then shapes our behavior, which affects our circumstances, which shapes subsequent predictions and feelings, and so on. A brain that is open to the environment creates feedback loops that affect itself over time; loops that can “spiral up,” or “spiral down.”

The relationship between our goal-directedness, predictions, and biochemistry is a little explored route to understanding the riddles of depression.

A Brain of Possibility Is A Brain of Risk

When nature created a representational brain in humans, it gave humans a new superpower no other animals had had before: imagination. Throughout evolutionary history, animals had long been limited to the world in front of them, trapped in a world of their immediate senses. Language would allow human beings to change all that, pairing words with mental constructs to enable a flexibility of thought. This would unlock an even cooler superpower: the altering of humanity’s relationship to all environments.

Some 50-70 thousand years ago, humans left Africa and began dominating every niche around the world. A key element of that stemmed from the newfound ability to imagine beyond a moment in time and space. Picturing new possibilities would mean exploring further and changing the environment to better suit us. For the first time, an animal found itself adapting the world to themselves.

No longer stuck in a cycle of reactive adaptation, people could now decide what the purpose of their goals would be. On the one hand, they would come to satisfy some sense of individual wellness and meaning. On the other, our social nature would push us toward being apart of a team, channeling ourselves in a new social direction of the human story, called cultural evolution.8 In fact, the relationship between wellness and social contribution may be a byproduct of social evolution, a way to reward us internally while driving humans toward new plateaus of complexity. But if so, it this positive development would have a dark side too: it would mean that people could experiment and make mistakes with their direction or well-being. Voles may not have much behind their eyes, but at least they don’t have to worry about never finding their calling, or about living in an existential hell as a result.

Imagination lets human beings play with their mental and emotional hardware to make new things possible; it allows people to create entirely new ways of being, and to shape their own destiny.

The problem is, with cognitive flexibility comes a trade-off: the potential to create buggy software that can negatively affect our emotional hardware. We call this domain mental health.

  1. The Brain That Changes Itself, by Norman Doidge
  2. From Primitive Parts, A Highly Evolved Human Brain, by John Hamilton
  3. On Intelligence, by Jeff Hawkins and Sandra Blakeslee (*key reading)
  4. Language and Species, by Derek Bickerton
  5. We CAN predict the future (a bit): Why the brain knows what’s going to happen before it does, by Graham Smith
  6. On Intelligence, by Jeff Hawkins and Sandra Blakeslee
  7. Hijacking the Brain Circuits with a Nickel Slot Machine, by Sandra Blakeslee
  8. Evolution’s Arrow, by John Stewart

 

Next—Depression, Pt II: A Brain For Faith And Hope