We can build cities and robots, we can land a probe on a meteor and mull the colonization of Mars - but can we understand the kilogram or so of grey matter that sits between our ears?

In 2016, the human brain is a paradox. Science has made great strides in the last decade: “optogenetics” could let us stimulate the brain with light, paralysed patients can control machines with their minds, and the next generation of computers will increasingly mimic the biological processes of the human brain.

But despite many breakthroughs, the most complex organ in our bodies is still the final frontier: “a black box” in the words of the neuro-technology pioneerRonen Gadot.

We are confronting the challenges of the 21st century with a primordial piece of kit that evolved over millennia to keep us safe from predators, and that we struggle to understand. One quarter of people around the world suffer from a mental illness, personal tragedies that take a toll on the global economy that is difficult to quantify but could amount to $2.5 trillion a year. Age-old instincts and biases still sap our potential and make us susceptible to the divisive politics of “us and them”.

The brain is a seething mass of billions of neurons, fizzing with connections, ideas and emotions, as ineffable as it is ingenious. How can we possibly get a grip on it? The World Economic Forum is launching a series of articles and videos that attempt to do just that, by tackling three key questions.

1. How can we rethink mental health?

“I have a serious mental illness. Specifically, I have bipolar disorder. I have been navigating how mental illness is treated for 18 years. And I strongly believe that how we treat mental illness is all wrong.”

These are strong words from Natasha Tracy, author of the book Lost Marbles: Insights into My Life with Depression and Bipolar. She pinpoints three main flaws in the US approach to mental health in her essay: the way mental illnesses are placed in a silo; paradoxically, a lack of specialist care; and a stigmatization that permeates everything from research dollars to social attitudes. We are long overdue an overhaul, she writes.

Mental illness is a scourge that afflicts rich and poor countries alike. As Thomas Insel, Director of the US National Institute of Mental Health, writes:

“Even in the developed world, it is estimated that only about half of all people with depression are diagnosed and treated. In the developing world, WHO estimates that 85% of people with a mental illness are untreated.”

The consequences of this dearth of care could not be more stark.

“Suicide causes more deaths than homicide. Around 7% of people with major depressive disorder will take their own lives. Globally, more than 800,000 people kill themselves every year.”

However, there is some hope that a new generation of therapies will provide a more nuanced understanding - and targeted treatments - for those suffering from a range of brain disorders, from depression and schizophrenia to diseases like Alzheimer’s.

I-han Chou, neuroscience editor at Nature magazine, explains how the emerging field of optogenetics - using light to stimulate genetically modified cells in the brain - could offer new treatments, as well open up new ethical questions.

Meanwhile, two entrepreneurs discuss their game-changing inventions: Tan Le, Founder and CEO of EMOTIV, has created wearable head-sets that work a bit like a fitbit for our minds to gauge the activity of our brains, while Ronen Gadot’s company ElMinda uses machine learning to decipher data on brain health.

Together, such technologies offer potential for a more personalized approach to health, for those who can afford it. As Gadot explains:

“Consider a neuro-degenerative disease such as Alzheimer’s. It actually starts some 20-30 years before it’s diagnosed. Because the brain is so sophisticated, it can compensate for deterioration in some neural pathways – the diagnosis happens only when it can’t compensate any more. But if we could tell what’s normal for each individual, we could see at a much earlier stage where patterns were changing in a way that indicate disease.”

For those of us lucky enough to be well, the pace of modern life can still put our brains under strain: hence the burgeoning field of “mindfulness”, or learning to focus calmly on the present. For the sceptics, Chade-Meng Tan, a Google engineer who went on to lead the company’s mindfulness programme, explains why his new vocation is not just “hippy BS”. He cites three recent pieces of research supporting its benefits, including:

“A 2012 study shows that eight weeks of mindfulness training can reduce social anxiety, depression and stress even more effectively than aerobic exercise.”

2. How can brain science help us to reach our potential, and avoid our pitfalls?

The year 2016 has been marked by populism, polarization and a frankly xenophobic debate on immigration. Do we blame politicians, inequality, a mismanaged refugee crisis - or a small, primitive part of our brain called the amygdala?

In an essay on how our brains developed to detect threats, Nayef al-Rodhan, a neuroscientist and philosopher, explains what fear looks like in the brain, and why we’re so susceptible to the politics of “us and them”.

“The neurocircuitry for tribal behaviour has been studied … we normally distinguish someone as being an “outsider” or part of “our group” within170 thousandths of a second from the moment we see them.”

And we judge them differently. A depressing picture of inevitable, in-built bias would emerge - were it not for a hopeful conclusion:

“While the human brain presents primordial predispositions, carried through millennia of evolution, it is also incredibly malleable and plastic. Rather than painting a grim picture, we should think of neuroscience as a discipline that can help us overcome roadblocks in our societies.”

What does “malleable and plastic” mean in this context? As this simple guide explains, plasticity means that our brains are literally shaped by our experiences. It’s a recent and quietly revolutionary concept. For one, it helps to debunk the lingering myth that men and women are born with very different brains that are predestined to develop along a certain path, as the neuroscientists Tara Swartand Murali Doraiswamy explain. Despite some biological differences, it turns out boys and girls are both competitive, and we’re all pretty bad at multi-tasking.

Moreover, our brains are never more malleable than in the first years of our lives. That is why it’s so important to understand how factors like poverty impact the way very young children’s brains develop, something that Casey Lew Williams, an Assistant Professor of Psychology, has been studying at the Princeton Baby Lab.

In a follow-up interview, he explained that impoverished children in the United States hear one-third of the words wealthier children do, which can contribute to developmental lags.

It’s a nuanced, complex topic, with one deceptively simple solution: more play time. Messing about with sticks is actually better for a child’s cognitive development than poring over flashcards, according to Lew Williams, but there are still obstacles to overcome.

“It's exhausting to be a parent in any circumstance, but it's much more exhausting to be a parent when you don't have the resources that other families have. Often, they (poor families) are juggling multiple jobs, they may not have access to reliable transportation, banking, healthcare; and there is greater incidence of problems such as stress or depression.”

While the seeds of inequality are sown in childhood, unequal societies also skew the way adults behave. The psychologists Paul Piff and Angela Robinsonreport on a series of studies that show that the wealthy are guilty of a slew of offences, from failing to stop at pedestrian crossings to breaching the ultimate ethical final frontier: stealing from a children’s candy jar. The findings should not be over-simplified: it’s not that wealth in itself corrupts, but that wealth tends to be isolating, eroding our ability to empathize.

But before you write off your own brain as a selfish, jittery, judgmental confectionery thief, take heart. Tinna C. Nielsen, an anthropologist and World Economic Forum YGL, and Lisa Kepinski, founder of the Inclusion Institute, offer a range of exercises to outsmart your mind in the workplace, so you can be aware, for example, of the fact that women get interrupted 2.8 times more often than men, and plan your meetings accordingly.

3. What are the promises and perils of new brain technologies?

Few would object to a brain-monitoring smartcap that picked up the early signs of Alzheimer’s. A world where employers use such technology to invade the last bastion of privacy and track whether their workers are alert and productive, or liable to gaze out of the window, is a different prospect. We need to do a better job of grappling with the ethics of the Fourth Industrial Revolution, argues Nita Farahany, a professor of law and philosophy at Duke University.

In some areas, of course, the benefits are clear-cut. Thanks to a pioneering programme, eight paralysed patients regained movement through a combination of virtual reality, a robotic walker and a brain-machine interface. This again reflects the brain’s adaptability: what’s exciting is not just that patients were able to control a computer using their minds, but that they experienced a partial neural recovery. As their brains believed they were causing their limbs to move, some fibres within the spinal cord were “woken up”, allowing patients to regain some voluntary movement. Richard Jones of Sheffield University explains how implants that transmit signals to the brain are already helping blind, deaf and severely disabled people to reconnect with the world.

The barrier between people and machines is getting thinner in more ways than one. Angeliki Pantazi explains her work within a team of scientists from IMB Research on “neuromorphic computing”, which draws inspiration from the inner workings of the biological brain to create a machine capable of more human-like leaps of creativity and insight.

While computers are excellent at some tasks, like complex calculations, they are notoriously bad at others; including football.

New discoveries in how “neural circuits” function will ultimately pave the way to more nimble computers, as Professor Michael Hausser of University College London explains. “We’re only just at the very beginning of our understanding of the human brain.”

The final frontier is less a fortress, more a fuzzy barrier that can be permeated by new ideas, offering us the hope to better understand ourselves and our societies.