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With greater accuracy, for example, marketers can comb large databases of consumer behavior to get more precise information on buying habits. And improvements in facial recognition are likely to make surveillance technology cheaper and more commonplace.

Modern artificial neural networks are composed of an array of software components, divided into inputs, hidden layers and outputs. The arrays can be “trained” by repeated exposures to recognize patterns like images or sounds.

“The point about this approach is that it scales beautifully. Basically you just need to keep making it bigger and faster, and it will get better. There’s no looking back now.”

Rabies moves at a predictable rate, replicating every eight to 10 hours, moving rapidly through chains of neurons and revealing a network. The researchers could allow the virus to move up the nervous system and reach the brain but could sacrifice the monkey before it showed any symptoms of infection.

When the virus has had enough time to travel a predictable distance, the researchers anesthetize the animal, wash out its blood, perfuse the central nervous system with fixatives, and use antibodies to detect where the virus has spread. The kills were timed to various stages to create a map. By the time you’ve gone through several sets of synapses that mapping is an enormous task. There’s an exponential increase in the number of neurons.

the researchers were astounded at what they saw. The motor areas in the brain connect to the adrenal glands. In the primary motor cortex of the brain, there’s a map of the human body—areas that correspond to the face, arm, and leg area, as well as a region that controls the axial body muscles (known to many people now as “the core”).

“Something about axial control has an impact on stress responses,” Strick reasons. “There’s all this evidence that core strengthening has an impact on stress. And when you see somebody that's depressed or stressed out, you notice changes in their posture. When you stand up straight, it has an effect on how you project yourself and how you feel.  Well, lo and behold, core muscles have an impact on stress. And I suspect that if you activate core muscles inappropriately with poor posture, that’s going to have an impact on stress.”

“These neural pathways might explain our intuitive sense for why there are many different strategies for coping with stress,” said Bruno. “I like the examples they give in the paper—that maybe this is why yoga and pilates are so successful. But there are lots of other things where people talk about mental imagery and all sorts of other ways that people deal with stress. I think having so many neural pathways having direct lines to the stress control system, that’s really interesting.”

Bruno specializes more in sensory neuroscience, so he read a more into the findings in the primary somatosensory cortex. Some of these tactile areas in the brain seem to be providing as much input to the adrenal medulla as the cortical areas. “To me that's really new and interesting,” said Bruno. “It might explain why certain sensations we find very relaxing or stressful.”

“It's not clear to me—from our work, and from their work—that what we call motor cortex is really motor cortex,” he said. “Maybe the primary sensory cortex is doing something more than we thought. When I see results like these, I go, hm, maybe these areas aren’t so simple.”

With this come implications for what’s currently known as “psychosomatic illness”—how the mind has an impact over organ functions. The name tends to have a bad connotation. The notion that this mind-body connection isn’t really real; that psychosomatic illnesses are “all in your head.” Elaborate connections like this would explain that, yes, it is all in your head. The fact that cortical areas in the brain that have multi-synaptic connections that control organ function could strip the negative connotations

As he put it, “How we move, think, and feel have an impact on the stress response through real neural connections.”

with the development of non-invasive brain imaging techniques, we have gathered evidence that suggests our brains are hard-wired to be unrealistically optimistic. When we learn what the future may hold, our neurons efficiently encode unexpectedly good information, but fail to incorporate information that is unexpectedly bad.

Underestimating risk makes us less likely to practice safe sex, save for retirement, buy insurance or undergo medical screenings.

Take the financial crisis of 2008. Each investor, homeowner, banker or economic regulator expected slightly better profits than were realistically warranted. On its own, each bias would not have created huge losses. Yet when combined in one market they produced a giant financial bubble that did just that.

The optimal solution then? Believe you will live a long healthy life, but go for frequent medical screenings. Aspire to write the next “Harry Potter” series, but have a safety net in place too.

In coming years, the approach will make possible a new generation of artificial intelligence systems that will perform some functions that humans do with ease: see, speak, listen, navigate, manipulate and control.

“We’re moving from engineering computing systems to something that has many of the characteristics of biological computing,” said Larry Smarr

The new approach, used in both hardware and software, is being driven by the explosion of scientific knowledge about the brain. Kwabena Boahen, a computer scientist who leads Stanford’s Brains in Silicon research program, said that is also its limitation, as scientists are far from fully understanding how brains function.

They are not “programmed.” Rather the connections between the circuits are “weighted” according to correlations in data that the processor has already “learned.” Those weights are then altered as data flows in to the chip, causing them to change their values and to “spike.” That generates a signal that travels to other components and, in reaction, changes the neural network, in essence programming the next actions much the same way that information alters human thoughts and actions.

Traditional computers are also remarkably energy inefficient, especially when compared to actual brains, which the new neurons are built to mimic. I.B.M. announced last year that it had built a supercomputer simulation of the brain that encompassed roughly 10 billion neurons — more than 10 percent of a human brain. It ran about 1,500 times more slowly than an actual brain. Further, it required several megawatts of power, compared with just 20 watts of power used by the biological brain.

Running the program, known as Compass, which attempts to simulate a brain, at the speed of a human brain would require a flow of electricity in a conventional computer that is equivalent to what is needed to power both San Francisco and New York, Dr. Modha said.

Perhaps some aspects of consciousness arise from these meta-networks -- and to investigate the proposition, the researchers analysed fMRI scans of 15 people after being injected with psilocybin, the active ingredient in magic mushrooms, and compared them to scans of their brain activity after receiving a placebo.

"One possible by-product of this greater communication across the whole brain is the phenomenon of synaesthesia" -- the experience, common during psychedelic experiences, of sensory mix-up: tasting colours, feeling sounds, seeing smells, and so on.

A truer way of visualising it, he said, would be in three dimensions, with connections between networks forming a sponge-like topography.

"The big question in neuroscience is where consciousness comes from," Petri said. For now, he said, "We don't know."