The Neurochemistry of Strategic Thinking?

 

Study Appears to Overturn Prevailing View of How the Brain is Wired

 

Posted on June 27, 2013By Neuroscience NewsFeatured, Neuroscience, Neuroscience Videos

 

A series of studies conducted by Randy Bruno, PhD, and Christine Constantinople, PhD, of Columbia University’s Department of Neuroscience, topples convention by showing that sensory information travels to two places at once: not only to the brain’s mid-layer (where most axons lead), but also directly to its deeper layers. The study appears in the June 28, 2013, edition of the journal Science.

 

For decades, scientists have thought that sensory information is relayed from the skin, eyes, and ears to the thalamus and then processed in the six-layered cerebral cortex in serial fashion: first in the middle layer (layer 4), then in the upper layers (2 and 3), and finally in the deeper layers (5 and 6.) This model of signals moving through a layered “column” was largely based on anatomy, following the direction of axons—the wires of the nervous system.

 

“Our findings challenge dogma,” said Dr. Bruno, assistant professor of neuroscience and a faculty member at Columbia’s new Mortimer B. Zuckerman Mind Brain Behavior Institute and the Kavli Institute for Brain Science. “They open up a different way of thinking about how the cerebral cortex does what it does, which includes not only processing sight, sound, and touch but higher functions such as speech, decision-making, and abstract thought.”

 

 

 

The researchers used the well-understood sensory system of rat whiskers, which operate much like human fingers, providing tactile information about shape and texture. The system is ideal for studying the flow of sensory signals, said Dr. Bruno, because past research has mapped each whisker to a specific barrel-shaped cluster of neurons in the brain. “The wiring of these circuits is similar to those that process senses in other mammals, including humans,” said Dr. Bruno.

 

The study relied on a sensitive technique that allows researchers to monitor how signals move across synapses from one neuron to the next in a live animal. Using a glass micropipette with a tip only 1 micron wide (one-thousandth of a millimeter) filled with fluid that conducts nerve signals, the researchers recorded nerve impulses resulting from whisker stimulation in 176 neurons in the cortex and 76 neurons in the thalamus. The recordings showed that signals are relayed from the thalamus to layers 4 and 5 at the same time. Although 80 percent of the thalamic axons went to layer 4, there was surprisingly robust signaling to the deeper layer.

 

To confirm that the deeper layer receives sensory information directly, the researchers used the local anesthetic lidocaine to block all signals from layer 4. Activity in the deeper layer remained unchanged.

 

“This was very surprising,” said Dr. Constantinople, currently a postdoctoral researcher at Princeton University’s Neuroscience Institute. “We expected activity in the lower layers to be turned off or very much diminished when we blocked layer 4. This raises a whole new set of questions about what the layers actually do.”

 

The study suggests that upper and lower layers of the cerebral cortex form separate circuits and play separate roles in processing sensory information. Researchers think that the deeper layers are evolutionarily older—they are found in reptiles, for example, while the upper and middle layers, appear in more evolved species and are thickest in humans.

 

One possibility, suggests Dr. Bruno, is that basic sensory processing is done in the lower layers: for example, visually tracking a tennis ball to coordinate the movement needed to make contact. Processing that involves integrating context or experience or that involves learning might be done in the upper layers. For example, watching where an opp

onent is hitting the ball and planning where to place the return shot.

“At this point, we still don’t know what, behaviorally, the different layers do,” said Dr. Bruno, whose lab is now focused on finding those answers.

 

A nerve cell in the thalamus (blue) sends its axon (red) into cerebral cortex, where it makes synaptic connections with thousands of neurons. While most of these connections are in a middle layer of the cortex (gray rings), some sparse branches connect to deeper layers.

 

Nobel-prize-winning neurobiologist Bert Sakmann, MD, PhD, of the Max Planck Institute in Germany, describes the study as “very convincing” and a game-changer. “For decades, the field has assumed, based largely on anatomy, that the work of the cortex begins in layer 4. Dr. Bruno has produced a technical masterpiece that firmly establishes two separate input streams to the cortex,” said Dr. Sakmann. “The prevailing view that the cortex is a collection of monolithic columns, handing off information to progressively higher modules, is an idea that will have to go.”2006-06-16 TC axon – high contrast MS1 repeat3-1

 

“Bruno’s work goes a long way toward overturning the conventional wisdom and provides new insight into the functional segregation of sensory input to the mammalian cerebral cortex, the region of the brain that processes our thoughts, decisions, and actions,” said Thomas Jessell, PhD, Claire Tow Professor of Motor Neuron Disorders in Neuroscience and a co-director of the Mortimer B. Zuckerman Mind Brain Behavior Institute and the Kavli Institute for Brain Science. “Developing a more refined understanding of cortical processing will take the combined efforts of anatomists, cell and molecular biologists, and animal behaviorists. The Zuckerman Institute, with its multidisciplinary faculty and broad mission, is ideally suited to building on Bruno’s fascinating work.”

 

Notes about this neuroanatomy and brain mapping research

 

Funding for the study was provided by the National Institute of Neurological Disorders and Stroke (Grant # NS069679), the Rita Allen Foundation, and the Klingenstein Fund.

 

The authors declare no financial or other conflicts of interests.

Contact: Karin Eskenazi – Columbia University Medical Center
Source: Columbia University Medical Center press release
Image Source: The anatomical diagram of the cerebral cortex is credited to Gray’s Anatomy and is in the public domain.
Video Source: The video, “A nerve cell in the thalamus (blue) sends its axon (red) into cerebral cortex”, is available on the Columbia University Medical Center YouTube page.
Original Research: Abstract for “Deep Cortical Layers Are Activated Directly by Thalamus” by Christine M. Constantinople and Randy M. Bruno in Science. Published online June 28 2013 DOI:10.1126/science.1236425

Programming Your Brain

The private sector knows how your brain works - and uses that to their advantage.  Political Parties are increasingly getting in on the game, too. 

If you knew you were being manipulated, wouldn't you want to know how to do something about it?  Wouldn't you want to protect your kids from being manipulated by teaching them how to defend against such violations of the self?

 

Child Brain Development – Hardware, Software, and Data

 

These days, a hot topic for parents: teen brain development. Books have been written about it. Nearly every magazine that a parent might read, including National Geographic, has had an article about it. I have written extensively about it.

 

But in all this writing – even in my own – something basic has remained vague. I’m referring to the phrase, “brain development,” and what is meant by it. If parents are to take all the advice and warnings seriously, they need be clear about what’s going on.

 

Because there are three types of brain development, and they happen in three different stages of human life. Only one of these stages relates to the teen brain. To make these distinctions, I’ll use the digital computer as an analogy – hardware, software and data.

 

STAGE #1 – BABY – Building the HARDWARE. The first stage happens while the baby is still in the mother’s womb. For nine months, the growing embryo slowly matures into a human child. Starting with a single cell, after nine months the baby’s brain has segmented itself into the many brain areas and has over 100 billion brain cells. Neither the baby nor the mother gets involved in this construction, except to maintain a healthy, undisturbed environment in the womb – and to be patient.

 At birth, none of these brain cells are wired together yet. The baby has the basic hardware, but neither the software nor the data.

 

STAGE #2 - CHILD – Programming basic SOFTWARE. In phases throughout early life, the child programs the many areas of his brain. Unlike computer software, which is an off-the-shelf package purchased and downloaded to the computer’s hardware, the child has to build the program himself. He has to wire his own brain. This happens when the child interacts with his world and exercises the basic functions. This activity causes the brain cells to connect into circuits. Not every child gets involved in the same activities, so not every child ends up with the same basic wiring and foundation capacity. The more an area is exercised, the more extensively it is wired. The last area to be wired is the prefrontal cortex, which is in charge of judgment and decision-making, i.e., intellect.

 

STAGE #3 - ADULT – Downloading add-ons and DATA. Once a brain area has its basic programming, a young person is then able to build on these networks by learning skills, knowledge and information. For example, once a child programs his brain for throwing, he can learn to throw a baseball or a football. Once he learns to swing a stick, he can learn to swing a baseball bat, a tennis racquet, or a golf club. He can learn facts and concepts about the sport, which would aid in performance. This capacity for learning – acquiring add-ons and data and using the basic software – continues throughout adult life.

 

In my writing I frequently refer to the prefrontal cortex (PFC), the area that is wired for basic functioning during adolescence. I sometimes call this the “smart” part of the brain because it’s involved in executive functions such as analysis, evaluation, decision-making, attention control, and foreseeing consequences. Because no other species has anything close to these capabilities, the PFC is the area that makes us uniquely human. We couldn’t be wise without an extensively developed PFC.

 

A baby has PFC hardware, but not the the software or the data. So throughout early childhood use of the PFC is minimal until adolescence, when a second massive wave of wiring happens in the PFC.

Then the child has a chance to construct the wiring for using these executive functions – for being “smart.” After adolescence is over, it’s about learning – inputting add-ons and data to be processed by the basic software.

 

This is why I emphasize the development of “adolescent brain” (the software of the PFC) as a critical turning point in a person’s life. It’s the time when a young person can do the thinking that will cause the PFC to wire itself. The PFC hardware has a chance to get some “smart” software.

 

But remember, not everyone ends up with the same software. Some young people work hard and end up with extensive wiring. Adults can provide learning opportunities and encouragement, but no one can do the thinking for him. An extensive network of wiring in the PFC is like having the most robust kind of intellectual software, a massive foundation that will accept an endlessly rich array of add-ons and data. In other words, a superior mind.

 

And of course, a minimally wired PFC will not.