Brain Decodes Skin Sensations

How the Brain Decodes the Skin Sensations

Bach-y-Rita determined that skin and its touch receptors could substitute for a retina, because both the skin and the retina are two-dimensional sheets, covered with sensory receptors, that allow a “picture” to form on them.

It's one thing to find a new data port, or way of getting sensations to the brain.  But it's another for the brain to decode these skin sensations and turn them into pictures. To do that, the brain has to learn something new, and the part of the brain devoted to processing touch has to adapt to the new signals. This adaptability implies that the brain is plastic in the sense that it can reorganize its sensory perceptual system.

If the brain can reorganize itself, simple localizationism cannot be a correct image of the brain. At first even Bach-y-Rita was a localizationist, moved by its brilliant accomplishments. Serious localizationism was first proposed in 1861, when Paul Broca, a surgeon, had a stroke patient who lost the ability to speak and could utter only one word. No matter what he was asked, the poor man responded, “Tan, tan,” When he died, Broca  dissected his brain and found damaged tissue in the left frontal lobe. Skeptics doubted that speech could be localized to a single part of the brain until Broca showed the the injured tissue, then reported on other patients who had lost the ability to speak and had damage in the same location. That place came to be called “Broca's area” and was presumed to coordinate the movements of the muscles of the lips and tongue. Soon afterward another physician, Carl Wernicke, connected damage in another brain area farther back to a different problem: the inability to understand language. Wernicke proposed that the damaged area was responsible for the mental representations of words and comprehension. It came to be known as “Wernicke's area.” Over the next hundred years localizationism became more specific as new research refined the brain map.

"We see with our brains, not with our eyes" (Bach-y-Rita, surgeon brain neuroplastician.) Illustration by Elena.

Unfortunately, though, the case for localizationism was soon exaggerated. It went from being a series of intriguing correlations (observations that damage to specific brain areas led to the loss of specific mental functions) to a general theory that declared that every brain function had only one hardwired location – an idea summarized by the phrase “one function, one location,” meaning that if a part was damaged, the brain could not reorganize itself or recover that lost function.

A dark age for plasticity began, and any exceptions to the idea of “one function, one location” were ignored. In 1868 Jules Cotard studied children who had early massive brain disease, in which the left hemisphere (including Broca's area) wasted away. Yet these children could still speak normally. This meant that even if speech tended to be processed in the hemisphere, as Broca claimed, the brain might be plastic enough to reorganize itself, if necessary. In 1876 Otto Soltmann removed the motor cortex from infant dogs and rabbits – the part of the brain thought to be responsible for movement – yet found they were still able to move. These findings were submerged in the wave of localizationist enthusiasm.

Bach-y-Rita came to doubt localizationism while in Germany in the early 1960s. He had joined a team that was studying how vision worked by measuring with electrodes electrical discharge from the visual processing area of a cat's brain. The team fully expected that when they showed the cat an image, the electrode in its visual processing area would send off an electric spike, showing it was processing that image. And it did. But when the cat's paw was accidentally stroked, the visual area also fired, indicating that it was processing touch as well. And they found that the visual area was also active when the cat heard sounds.

The Brain that Changes Itself by Norman Doidge, M.D. Stories of Personal Triumph from the Frontiers of Brain Science.

Nobody will torture cats. Photo by Elena.

Brain Development

Brain Development

Anatomy and physiology are not glamorous subjects – a complete knowledge of them requires careful and intensive study. But the provide the very bedrock of the subject matter. It is easy to overlook the fact that the brain is, after all, just an organ. It is an organ like the liver or the spleen or the stomach. Like these other organs of the body, it is made of cells. These cells are connected together to form a piece of tissue with a certain characteristic texture and shape, and so the brains of all of look roughly the same. And yet, there is something almost miraculously special about this organ: it is the organ of the mind – indeed, of our very selves.

Despite this unique property of the brain, its cells are not fundamentally different from the cells of other bodily organs. What is the prototypical nerve cell? It consists of three basic parts. The first, the cell body, contains essentially the same things found in cells in other organs – namely, the things that govern its basic metabolism. There are two types of appendages to this cell body, one of which is known as the dendrites, the other as the axon; in our prototypical nerve cell, there are many dendrites but only a single axon. Together, these three components form the typical structure of a brain cell – a neuron. Neurons (in conjunction with some supporting cells called glia) are all that the nervous system is made of – billions and billions of cells, connected up with one another.

This interconnection takes place as follows: The axon of one neuron links up with a dendrite of another neuron, whose axon in turn links with a dendrite of another neuron, and so on; multiple interconnections can occur, as each dendrite on a neuron can accept many axon terminals. At the place where two cells link up – between the axon of one cell and a dendrite of the other – there is a minute gap, called a synapse. Over the synaptic gap, small chemical molecules pass from one neuron to the next; these molecules are called neurotransmitters. This transmission of chemical is the principal means of communication between the cells of the brain. Different cells located in different brain regions use different types of neurotransmitters.

A living creature, and especially a human being, is first and last a subject, not an object. Photo by Elena.

These five concepts – cell body, dendrite, axon, synapse, neurotransmitter – are all that one really need to know about neurons as basic concepts.

What is it, then, that makes this organ so unique – how is it that these interconnected cells produce something as miraculous as our awareness of being in the world? How can it be that the physiological activity of these cells, comprising this lump of tissue, produces something so utterly unlike anything that any other organ produces – indeed, so utterly unlike anything else in the physical universe?

Although the elementary properties of neural tissue obviously do not explain how or why the brain produces subjective awareness, there are two features about it that are quite unusual. These features are not fundamental, but they do distinguish the cells of the brain from those of most other bodily organs. The first distinguishing feature of neurons is the nature of the links between them: the synopsis mediated by neurotransmitters. This linkage permits the passing of “information” from one cell to another. The principle of information transfer is not unique to nerve cells (other cells also interact with each other in various ways), but the dedicated function of communication between nerve cells is an important distinguishing feature.

The second outstanding feature of brain tissue is that, while the basic plan of the brain's organization is, as it were, predetermined by our genes, the overall plan is dramatically modified by environmental influences during life. The brain comes into the world with innumerable potential patterns of detailed organization, as reflected in the infinite combinations through which its cells could connect up with each other. The precise way that they do connect up, in each and every one of us, is largely determined by the idiosyncratic environment in which each brain find itself. In other words, the way our neurons connect up with each other depends on what happens to us. Modern neurons connect up with each other depends on what happens to us.

Modern neuroscience is becoming increasingly aware of the role played in brain development by experience, learning, and the quality of the facilitating environment – and not only during childhood. In short, the fine organization of the brain is literally sculpted by the environment in which it finds itself – far more so than any other organ in the body, and over much longer periods of time.

At the level of neural tissue, then, these two features – the capacity for information transfer and that for learning – are what most distinguishes the brain from other organs. These capacities are present far more potently in brain tissue than in any other tissue of the body.

Neuropsychology, like classical neurology, aims to be entirely objective, and its great power, its advances, come from just this. Illustration by Elena.

The Brain and the Inner World, Introduction to Basic Concepts. Mark Solms, Oliver Turnbull.

Mind and Brain

Mind and Brain – How Do They Relate?

One of the main points is that the brain is simply a bodily organ, like the stomach, the liver, or the lungs. It is tissue, made of cells. These cells do have some special properties, but they are of roughly the same type and employ roughly the same sort of metabolic and other processes as other cells in the body. And yet the brain has a special, mysterious property that distinguishes it from all other organs. It is the seat of the mind, somehow producing our feeling of being ourselves in the world right now. Trying to understand how this happens – how matter becomes mind – is the mind-body problem.

The mind-body problem is a philosophical conundrum that dates back to classical antiquity, and probably beyond. What has changed in recent years is the emergence of a comprehensive scientific effort to solve this ancient problem. This effort, which involves neuroscientists, psychologists, and even philosophers, takes the form of a multidisciplinary enterprise called cognitive science.

The advent of science to the problem has changed it slightly. In that the mind-body problem is now commonly described as the problem of “consciousness.” In other words, the problem, “how does the mind emerge from the brain”, had become, “how does consciousness emerge from the brain.” Although psychonalytically minded readers need to reminding that mental life is not synonymous with consciousness, we will not address this particular twist to the problem. Let us assume that the two ways of putting the problem are synonymous.

Investigating consciousness has become the second career of Francis Crick, the Nobel Prize-winning biologist famous for being the codiscoverer (in the 1950s) of the double-helix structure of DNA. In his book, entitled The Astonishing Hypothesis, he writes:

“The astonishing hypothesis is that you, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells and their associated molecules (Crick, 1994, p.3).

The hypothesis seems self-evidently true, and yet it is something that many people do not find easy to accept. How can all this – all that comprises you – be reduced to the activity of a group of cells? The subtitle of Crick's book is The Scientific Search for the Soul. This (perhaps overstated) phrase captures something of the magnitude of the problem. The individual cells of the brain are not uniquely “mental”, yet when they are connected up together, each one contributes something to something else that somehow becomes the mind.

Cognitive science is an unfortunate term in that it implies an exclusion of noncognitive mental functions such as emotion and motivation. Illustration by Elena.

Space Tourism

A Reality of Space Tourism

Space is truly the final frontier for mankind. As future space tourists, we should keep our eyes on the fast-developing space industry, as it will shape our civilization for decades to come.

Imagine yourself heading out with your family on your annual vacation. Except, this time you aren’t going to a harbour for a Caribbean cruise or to an airport for a Chilean skiing tour. Instead you thrill to the idea that in a couple of hours you’ll be in a spaceport, waiting in line to take your places in a spaceship for this much-anticipated trip to the Moon. This scenario is a likely picture of what might be encountered in the next few decades.

This isn’t to say that space tourism isn’t available now; in fact, Russia has previously allowed some space tourists to travel alongside their cosmonauts to the International Space Station (ISS) for anywhere between 20 and 40 million US dollars (an insignificant sum for some of us, the Earthlings).

The goal, however, for the burgeoning space tourism sector is to make these trips more affordable for the average citizen and to provide infrastructure needed to make spaceflights possible. Today, most of the spacecraft can no longer be used after completing their mission and are discarded, which can prove to be extremely costly. Thus, companies wishing to invest in space tourism are currently researching methods of reusable space transportation.

SpaceX, for instance, has a prototype spaceship called Dragon that can transport up to 7 crew members. It is currently working with NASA to find a way to transport people headed to the orbit to work there, but it also hopes to provide commercial spaceflights to ordinary citizens.

Reaction Engines Ltd has proposed a “space-plane” named SKYLON that produces thrust by burning liquid hydrogen fuel with the oxygen from the air, significantly reducing the amount of liquid oxygen needed on board the ship to burn the fuel. Its SABRE engines will accelerate the ship to Mach 5 – that’s 6125 km/hour up until 25 kilometers above sea level, at which point the engines will switch to rocket mode and carry it the rest of the way to space.

The design received endorsement from the European Space Agency (ESA) in November 2012, and they were looking for funding to build there SABRE engines.

Another well-known company, Virgin Galactics, already had more than 500 ticket holders in 2014 waiting to catch a ride on board SpaceShipTwo, a spaceship that can hold two crew members and six passengers. The Virgin Galactics plans for this spacecraft to be the first ship that sends  tourists to space on a regular basis. The ticket price is currently reported to be $200,000 with a $20,000 down payment, a price much more lower that what the Russians charge. One of the first few planned trips are supposed to take passengers 110 kilometers above sea level marking the beginning of open space, for a total weightlessness duration of 6 minutes.

It is important to keep in mind that these ships will need dedicated ports to house them and to accommodate them for takeoff and landing. Several of these have already been open, like Spaceport America in New Mexico, open for business since 2011 and a few others are being built.

In addition to transportation, future space travelers will need tourist destinations to visit and accommodations to live in for the duration of their journey. A couple of companies are looking into providing housing for these individuals during their stay before the takeoff.

Bigelow Aerospace Company plans to send housing modules into space alongside spacecraft. These modules are compact rooms that can inflate upon command to form livable areas that are shielded from the radiation of the Sun. Theoretically Bigelow Aerospace could build an entire hotel room by room just by interconnecting these modules, effectively creating new destinations in space for tourists. One of these modules is destined to connect to the International Space Station in 2015 or later, providing Bigelow Aerospace with a chance to demonstrate their concept.

Space Island Group, another contender in the space tourism business, intends to build ring-like structures that can spin at variable speeds to create an artificial gravity that is equal to a third of the gravity of Earth. This could be highly beneficial, as it may potentially eliminate many of the negative effects that come from prolonged exposure to low-gravity environments, such as muscle atrophy or loss of bone density.

Naturally, all these accommodations will need to regularly stock oxygen, food, water and other supplies for the guests. While some of these necessities could be grown or recycled on the stations themselves, most supplies would still need to be sent directly from Earth. One candidate for these missions is SpaceX’s Falcon 9, which is capable of carrying a total of 10T of cargo, more than enough to resupply future space hotels. As a matter of fact, in 2008 already NASA employed Falcon 9 to send supplies to the International Space Station, thus illustrating its potential as a reliable cargo carrier.

Safety will be one of the main factors that will make or break the future of space tourism. Before governments can allow their citizens to leave the planet, companies must prove that their shuttles and living quarters will protect their customers throughout their journey.

The US government has already begun to draft some guidelines to ensure safety of their citizens who wish to travel to space. In 2004, the Commercial Space Launch Amendments Act, H.R. 5382, was signed into law. It provides rules and regulations that space companies must follow to legally send people to space, such as getting a license from the Federal Aviation Administration’s Office of Commercial Space Transportation (FAA/AST).

… After all, we might soon find ourselves staring at a tiny blue dot outside our windows and reminiscing of a time when this was all but an impossible dream…

Sources:

• Roupen Djinbachian, Space Tourism close to becoming a reality Technophilic, Winter 2013, page 22).
• Space Tourist Back From “Paradise”, Lands on Steppes”, by Patrick E. Tyler.
• Elysium, movie 2013.
• Clark, Stephen (September 2010), “Boeing allies with Space Adventures for tourist flights”.
• “Anywhere on Earth in four hours? Top-secret Skylon space plane could replace jets and rockets, company claims”. National Post, 29 November 2012.
• “Branson Dedicates Space Terminal”, Wall Street Journal, 18 October 2011.
• “International space station to receive inflatable module”, Washington Post, 16 January 2013.
• “Private-spaceflight bill signed into law”, NBC News, 23 December 2004.

What will we discover in Outer Space, is nothing compared with our beloved planet (Quotations from Megan Jorgensen). Image : © Megan Jorgensen.

Dreams in Psychology

Dreams in Psychology

Why are dreams so important in analysis. Patients are often haunted by recurring dreams of their traumas and awaken in terror. As long as they remain ill, these dreams don't change their basic structure. The neural network that represents the trauma – such as Mr. L's dream that he was missing something – is persistently reactivated, without being retranscribed. Should these traumatized patients get better, these nightmares gradually become less frightening, until ultimately the patient dreams something like At first I think the trauma is recurring, but it isn't; it's over now, I've survived . This kind of progressive dream series shows the mind and brain slowly changing, as the patient learns that he is safe now. For this to happen, neural networks must unlearn certain associations – as Mr. L. unlearned his association between separation and death – and change existing synaptic connections to make way for new learning.

What physical evidence exists that dreams show our brains in the process of plastic change, altering hitherto buried, emotionally meaningful memories, as in Mr. L.'s case?

The newest brain scans show that when we dream, that part of the brain that processes emotion, and our sexual, survival, and aggressive instincts, is quite active. At the same time the prefrontal cortex system, which is responsible for inhibiting our emotions and instincts, shows lower activity. With instincts turned up and inhibitions turned down, the dreaming brain can reveal impulses that are normally blocked from awareness.

Scores of studies show that sleep affects plastic change by allowing us to consolidate learning and memory. When we learn a skill during the day, we will be better at it the next day if we have a good night's sleep. “Sleeping on a problem” often does make sense.

A team led by Marcos Frank has also shown that sleep enhances neuroplasticity during the critical period when most plastic change takes place. Huben and Wiesel blocked one eye of a kitten in the critical period and showed that the brain map for the blocked eye was taken over by the good eye – a case of use it or lose it. Frank's team did the same experiment with two groups of kittens, one group that it deprived of sleep, and another group that got a full amount of it. They found that the more sleep the kittens got, the greater the plastic change in their brain map.

Scientists blocked one eye of a kitten and showed that the brain map for the blocked eye was taken over by the good eye. Photo by Elena.

The dream state also facilitates plastic change. Sleep is divided into two stages, and most of our dreaming occurs during one of them, called rapid-eye-movement sleep, or REM sleep. Infants spend many more hours in REM sleep than adults, and it is during infancy that neuroplastic change occurs most rapidly. In fact, REM sleep is required for the plastic development of the brain infancy. A team led by Dr. Gerald Marks did a study similar to Frank's that looked at the effects of REM sleep on kittens and on their brain structure. Marks found that in kittens deprived of REM sleep, the neurons in their visual cortex were actually smaller, so REM sleep seems necessary for neurons to grow normally. REM sleep has also been shown to be particularly important for enhancing our ability to retain emotional memories and for allowing the hippocampus to turn short-term memories of the day before into long-term ones (i.e., it helps make memories more permanent, leading to structural change in the brain).

Each day, in analysis, Mr. L, worked on his core conflicts, memories, and traumas, and at night there was dream evidence not only of his buried emotions but of his brain reinforcing the learning and unlearning he had done.

We understand why Mr. L. at the outset of his analysis, had no conscious memories of the first four years of his life: most of his memories of the period were unconscious procedural memories – automatic sequences of emotional interactions – and the few explicit memories he had were so painful, they were repressed. In treatment he gained access to both procedural and explicit memories from his first four years. But why was he unable to recall his adolescent memories? One possibility is that he repressed some of his adolescence; often when we repress one thing, such as a catastrophic early loss, we repress other events loosely associated with it, to block access to the original.

But there is another possible cause. It has recently been discovered that early childhood trauma causes massive plastic change in the hippocampus, shrinking it so that new, long-term explicit memories cannot form. Animals removed from their mothers let out desperate cries, then enter a turned-off state – as Spitz's infants did – and release a stress hormone called “glucocorticoid.” Glucocorticoids kill cells in the hippocampus so that it cannot make the synaptic connections in neural networks that make learning and explicit long-term memory possible. These early stresses predispose these motherless animals to stress-related illness for the rest of their lives. When they undergo long separations, the gene to initiate production of glucocorticoids gets turned on and stays on for extended periods. Trauma in infancy appears to lead to a supersensitization – a plastic alteration – of the brain neurons that regulate glucocorticoids. Recent research in humans shows that adult survivors or childhood abuse also show signs of glucocorticoid supersensitivity lasting into adulthood.

That the hippocampus shrinks is an important discovery. Depression, high stress, childhood trauma all release glucocorticoids and kill cells in the hippocampus, leading to memory loss. The longer people are depressed, the smaller their hippocampus gets. The hippocampus of depressed adults who suffered prepubertal childhood trauma is 18 percent smaller than that of depressed adults withous childhood trauma – a downside of the plastic brain : we literally lose essential cortical real estate in response to illness.

If the stress is brief, this decrease in size is temporary. If it is too prolonged, the damage is permanent. As people recover from depression, their memories return, and research suggests their hippocampi can grow back. In fact, the hippocampus is one of two areas where new neurons are created from our own stem cells as part of normal functioning.

Antidepressant medications increase the number of stem cells that become new neurons in the hippocampus. Rats given Prozac for three weeks had a 70 percent increase in the number of cells in their hippocampi. It usually takes three to six weeks for antidepressants to work in humans – perhaps coincidentally, the same amount of time it takes for newly born neurons in the hippocampus to mature, extend their projections, and connect with other neurons. So we may, without knowing it, have been helping people get out of depression by using medications that foester brain plasticity. Since people who improve in psychotherapy also find that their memories improve, it may be that it also stimulates neural growth in their hippocampi.

(Turning Our Ghosts into Ancestors. The Brain That Changes Itself by Norman Doidge, M.D., excerpt).

We are often haunted by important relationships from the past that influence us unconsciously in the present. Photo by Elena.