Category Archives: Brain

Drugs and the Brain

The human brain is the most complex organ in the body. This three-pound mass of gray and white matter sits at the center of all human activity—you need it to drive a car, to enjoy a meal, to breathe, to create an artistic masterpiece, and to enjoy everyday activities. In brief, the brain regulates your body’s basic functions; enables you to interpret and respond to everything you experience; and shapes your thoughts, emotions, and behavior.

The brain is made up of many parts that all work together as a team. Different parts of the brain are responsible for coordinating and performing specific functions. Drugs can alter important brain areas that are necessary for life-sustaining functions and can drive the compulsive drug abuse that marks addiction. Brain areas affected by drug abuse include:

  • The brain stemwhich controls basic functions critical to life, such as heart rate, breathing, and sleeping.
  • The cerebral cortex, which is divided into areas that control specific functions. Different areas process information from our senses, enabling us to see, feel, hear, and taste. The front part of the cortex, the frontal cortex or forebrain, is the thinking center of the brain; it powers our ability to think, plan, solve problems, and make decisions.
  • The limbic system, which contains the brain’s reward circuit. It links together a number of brain structures that control and regulate our ability to feel pleasure. Feeling pleasure motivates us to repeat behaviors that are critical to our existence. The limbic system is activated by healthy, life-sustaining activities such as eating and socializing—but it is also activated by drugs of abuse. In addition, the limbic system is responsible for our perception of other emotions, both positive and negative, which explains the mood-altering properties of many drugs.

How do the parts of the brain communicate?

The brain is a communications center consisting of billions of neurons, or nerve cells. Networks of neurons pass messages back and forth among different structures within the brain, the spinal cord, and nerves in the rest of the body (the peripheral nervous system). These nerve networks coordinate and regulate everything we feel, think, and do.

  • Neuron to Neuron
    Each nerve cell in the brain sends and receives messages in the form of electrical and chemical signals. Once a cell receives and processes a message, it sends it on to other neurons.
  • Neurotransmitters – The Brain’s Chemical Messengers
    The messages are typically carried between neurons by chemicals called neurotransmitters.
  • Receptors – The Brain’s Chemical Receivers
    The neurotransmitter attaches to a specialized site on the receiving neuron called a receptor. A neurotransmitter and its receptor operate like a “key and lock,” an exquisitely specific mechanism that ensures that each receptor will forward the appropriate message only after interacting with the right kind of neurotransmitter.
  • Transporters – The Brain’s Chemical Recyclers
    Located on the neuron that releases the neurotransmitter, transporters recycle these neurotransmitters (that is, bring them back into the neuron that released them), thereby shutting off the signal between neurons.

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To send a message, a brain cell (neuron) releases a chemical (neurotransmitter) into the space (synapse) between it and the next cell. The neurotransmitter crosses the synapse and attaches to proteins (receptors) on the receiving brain cell. This causes changes in the receiving cell—the message is delivered.

How do drugs work in the brain?

Drugs are chemicals that affect the brain by tapping into its communication system and interfering with the way neurons normally send, receive, and process information. Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter. This similarity in structure “fools” receptors and allows the drugs to attach onto and activate the neurons. Although these drugs mimic the brain’s own chemicals, they don’t activate neurons in the same way as a natural neurotransmitter, and they lead to abnormal messages being transmitted through the network.

Other drugs, such as amphetamine or cocaine, can cause the neurons to release abnormally large amounts of natural neurotransmitters or prevent the normal recycling of these brain chemicals. This disruption produces a greatly amplified message, ultimately disrupting communication channels.

How do drugs work in the brain to produce pleasure?

Most drugs of abuse directly or indirectly target the brain’s reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, motivation, and feelings of pleasure. When activated at normal levels, this system rewards our natural behaviors. Overstimulating the system with drugs, however, produces euphoric effects, which strongly reinforce the behavior of drug use—teaching the user to repeat it.

Most drugs of abuse target the brain’s reward system by flooding it with dopamine.

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How does stimulation of the brain’s pleasure circuit teach us to keep taking drugs?

Our brains are wired to ensure that we will repeat life-sustaining activities by associating those activities with pleasure or reward. Whenever this reward circuit is activated, the brain notes that something important is happening that needs to be remembered, and teaches us to do it again and again without thinking about it. Because drugs of abuse stimulate the same circuit, we learn to abuse drugs in the same way.

Why are drugs more addictive than natural rewards?

When some drugs of abuse are taken, they can release 2 to 10 times the amount of dopamine that natural rewards such as eating and sex do.15 In some cases, this occurs almost immediately (as when drugs are smoked or injected), and the effects can last much longer than those produced by natural rewards. The resulting effects on the brain’s pleasure circuit dwarf those produced by naturally rewarding behaviors.16,17The effect of such a powerful reward strongly motivates people to take drugs again and again. This is why scientists sometimes say that drug abuse is something we learn to do very, very well.

Long-term drug abuse impairs brain functioning.

What happens to your brain if you keep taking drugs?

For the brain, the difference between normal rewards and drug rewards can be described as the difference between someone whispering into your ear and someone shouting into a microphone. Just as we turn down the volume on a radio that is too loud, the brain adjusts to the overwhelming surges in dopamine (and other neurotransmitters) by producing less dopamine or by reducing the number of receptors that can receive signals. As a result, dopamine’s impact on the reward circuit of the brain of someone who abuses drugs can become abnormally low, and that person’s ability to experience anypleasure is reduced.

This is why a person who abuses drugs eventually feels flat, lifeless, and depressed, and is unable to enjoy things that were previously pleasurable. Now, the person needs to keep taking drugs again and again just to try and bring his or her dopamine function back up to normal—which only makes the problem worse, like a vicious cycle. Also, the person will often need to take larger amounts of the drug to produce the familiar dopamine high—an effect known as tolerance.

Decreased Dopamine Transporters in a Methamphetamine Abuser18

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How does long-term drug taking affect brain circuits?

We know that the same sort of mechanisms involved in the development of tolerance can eventually lead to profound changes in neurons and brain circuits, with the potential to severely compromise the long-term health of the brain. For example, glutamate is another neurotransmitter that influences the reward circuit and the ability to learn. When the optimal concentration of glutamate is altered by drug abuse, the brain attempts to compensate for this change, which can cause impairment in cognitive function. Similarly, long-term drug abuse can trigger adaptations in habit or non-conscious memory systems. Conditioning is one example of this type of learning, in which cues in a person’s daily routine or environment become associated with the drug experience and can trigger uncontrollable cravings whenever the person is exposed to these cues, even if the drug itself is not available. This learned “reflex” is extremely durable and can affect a person who once used drugs even after many years of abstinence.

What other brain changes occur with abuse?

Chronic exposure to drugs of abuse disrupts the way critical brain structures interact to control and inhibit behaviors related to drug use. Just as continued abuse may lead to tolerance or the need for higher drug dosages to produce an effect, it may also lead to addiction, which can drive a user to seek out and take drugs compulsively. Drug addiction erodes a person’s self-control and ability to make sound decisions, while producing intense impulses to take drugs.

Speaking of Psychology: The neuroscience of creativity

Do you have to be intelligent to be creative? Can you learn to be more creative? In this episode, we speak with neuropsychologist Rex E. Jung, PhD, who studies intelligence, creativity and brain function. He discusses why – even if it sounds counterintuitive – intelligence and creativity may not have all that much in common.

Transcript of interview with Audrey and Rex Jung from the APA website.

Audrey Hamilton: Do you have to be intelligent to be creative? Can you really learn to be more creative? In this episode, we speak with one neuropsychologist who studies intelligence, creativity and brain function. He talks about why – even if it sounds counterintuitive – intelligence and creativity may not have all that much in common. I’m Audrey Hamilton and this is “Speaking of Psychology.”Behavior Influences Attitudes

Rex Jung is an assistant professor of neurosurgery at the University of New Mexico and a practicing clinical neuropsychologist in Albuquerque. He studies both brain disease and what the brain does well – a field of research known as positive neuroscience. His research is designed to relate behavioral measures, including intelligence, personality and creativity to brain function and structure. He has published research articles across a wide-range of topics including traumatic brain injury, lupus, schizophrenia, intelligence and creativity. Welcome, Dr. Jung.

Rex Jung: Thank you, Audrey.

Audrey Hamilton: Could you first of all explain neuroimaging and tell our listeners how it helps researchers understand how people think and act?

Rex Jung: Sure. So, neuroimaging is the tool that we use to measure the brain and there’s lots of different neuroimaging techniques. I use three main neuroimaging techniques – the first that I learned in graduate school was magnetic resonance microscopy, which sounds kind of complicated. But, it is a technique that basically looks at the chemicals in your brain. It’s in a standard MRI machine like you would go to get your knee scanned. But, using some sophisticated techniques you can look at certain chemicals in the brain. Some of those chemicals are very involved in important neuronal processes. And we’ve correlated those with behavior.

A different technique is called diffusion tensor imaging, which allows us to look at water movement in the brain. And this is important because there’s lots of tubes going through your brain like the wires that connect up your computer to the Internet. And these tubes, called axons, are connecting up different processing modules of your brain and those have to be healthy. So, we can look at the health of those axons, those myelinated axons, the fatty sheath like the insulation that surrounds those tubes.

The third technique that we use is just structural magnetic resonance imaging and that allows us to look at the processing modules of the brain – the cortical thickness – the computers that are on the surface of the brain and how much or little of that you have on the surface of the brain. Those are the three main techniques that I use. There’s functional imaging, fMRI, that most people have heard of where you’re looking a blood flow, as well. Those are ways that we measure brain structure and function and this gives us the ability to do scientific measures that then we can correlate to behavioral measures in psychology.

Audrey Hamilton: Does being highly creative mean you’re also more intelligent?

Rex Jung: Not necessarily. There’s a controversy about this in the psychological literature and some people have found correlations between creativity and intelligence. They’re usually pretty low, this association. And some people make a lot of that, this low association. But usually, because this association between creativity and intelligence is low, it means that you don’t necessarily have to be intelligent to be creative. So, I spent over a decade studying intelligence. It’s one of the reasons I started studying creativity because it seemed like something distinctly different and interesting than intelligence, which I have studied. I work with very highly intelligent people in academia and scientists and not all of them are creative. Why is that? If they do go together I would be working with all of the creative people in my city in Albuquerque, but that wasn’t the case so creativity seemed to be something different.

Audrey Hamilton: Can a person learn to become more creative or simply gain intelligence?

mousebored.jpgRex Jung: There are some tools and techniques that can help people to be more creative. We’re starting to learn more about creativity and it’s one of the things that I’m excited about in terms of creativity is that there might be ways to increase your creative capacity.

Intelligence unfortunately seems to be much more under tight genetic control. The genetic correlates of intelligence are high, like .75. So, if you have twins – they’re going to be identical twins – their correlation of their intelligence with one another is going to be very, very high. So that implies that the genetic involvement of that capacity is under much more tight control than the environment would be.

With creativity, we don’t have that information and I’m hopeful that you can modulate or modify creative cognition much more than intelligence. There are studies out there that have shown increases in intelligence scores of two, maybe three points on a particular measure, which are not particularly high. But those are also controversial. Some have been replicated. Some haven’t been replicated. And we really don’t see that in terms of intelligence. With creativity, there’s a pitched effort to try to increase creativity scores on some of these measures and we’re seeing some good initial results and I’m very hopeful about that.

Audrey Hamilton: How does the way a person’s brain works and is structured influence how creative or intelligent he or she is?

Rex Jung: The research that we’ve done shows that the brain organization of intelligence and creativity are quite different. So, when you think about those measures that I talked about, those neuroimaging measures, the brain of someone who is intelligent – think of bigger, better, stronger, faster – all the measures are pointing to higher integrity of the brain of someone who has high intelligence. So, the cortical mantle is thicker, the white matter, the wires are more myelinated, the water can travel faster and in a coherent direction, you have more of these certain chemicals that I was talking about.

Audrey Hamilton: It’s beefed up.

Rex Jung: It’s beefed up, yes. So you can have a better organized brain.

With creativity, the story was different. In different regions of the brain, we were seeing weaker connections, thinner cortex and different levels of these same biochemicals. So, it was really clear from these studies that intelligence and creativity were different because we were seeing different pictures in the measures we were taking of the brain. But I tend to look at creativity and intelligence as two different kinds of reasoning. That creativity is kind of reasoning without all of the information present. So, call it abductive reasoning. But, you have hypothesis testing about how the world could work without all of the information present. So, you have to use abstraction and metaphor and stuff like that about this might look like this or this might be this way.

With intelligence, you’re using deductive reasoning, where it’s rule-based reasoning where a equals b and that’s the way it goes. You have a rule for how this relationship works. So, creativity and intelligence are probably different types of reasoning. Both are very adaptive, but they’re just different for different types of problems that you have to solve out in the world.

Audrey Hamilton: Is real creativity rare? How about genius?

Rex Jung: So, creativity is common and genius is a lot more rare than we would believe. The term genius gets thrown around a lot. But, I think genius is rare because that combination of brain organization where you have high fidelity, beefed up brain in certain regions and then kind of down regulated brain in other regions is really going to be kind of rare where that is present in the same brain. So, to have that back and forth between intelligence and creativity, the ability to do both of those reasoning processes well, where you can do first approximations, hypothesis testing, abstraction and then create a rule, a novel and useful rule out of nothing before is rare and that is true genius.

Audrey Hamilton: Well great. Thank you so much for joining us, Dr. Jung. It’s been very, very interesting.

Rex Jung: Great. Thank you, Audrey.

Intelligence, creativity and brain function

Do you have to be intelligent to be creative? Can you learn to be more creative? In this episode, we speak with neuropsychologist Rex E. Jung, PhD, who studies intelligence, creativity and brain function. He discusses why – even if it sounds counterintuitive – intelligence and creativity may not have all that much in common.

Transcript of interview with Audrey and Rex Jung from the APA website.

Audrey Hamilton: Do you have to be intelligent to be creative? Can you really learn to be more creative? In this episode, we speak with one neuropsychologist who studies intelligence, creativity and brain function. He talks about why – even if it sounds counterintuitive – intelligence and creativity may not have all that much in common. I’m Audrey Hamilton and this is “Speaking of Psychology.”

Rex Jung is an assistant professor of neurosurgery at the University of New Mexico and a practicing clinical neuropsychologist in Albuquerque. He studies both brain disease and what the brain does well – a field of research known as positive neuroscience. His research is designed to relate behavioral measures, including intelligence, personality and creativity to brain function and structure. He has published research articles across a wide-range of topics including traumatic brain injury, lupus, schizophrenia, intelligence and creativity. Welcome, Dr. Jung.creative-art-brain-300x300

Rex Jung: Thank you, Audrey.

Audrey Hamilton: Could you first of all explain neuroimaging and tell our listeners how it helps researchers understand how people think and act?

Rex Jung: Sure. So, neuroimaging is the tool that we use to measure the brain and there’s lots of different neuroimaging techniques. I use three main neuroimaging techniques – the first that I learned in graduate school was magnetic resonance microscopy, which sounds kind of complicated. But, it is a technique that basically looks at the chemicals in your brain. It’s in a standard MRI machine like you would go to get your knee scanned. But, using some sophisticated techniques you can look at certain chemicals in the brain. Some of those chemicals are very involved in important neuronal processes. And we’ve correlated those with behavior.

A different technique is called diffusion tensor imaging, which allows us to look at water movement in the brain. And this is important because there’s lots of tubes going through your brain like the wires that connect up your computer to the Internet. And these tubes, called axons, are connecting up different processing modules of your brain and those have to be healthy. So, we can look at the health of those axons, those myelinated axons, the fatty sheath like the insulation that surrounds those tubes.

The third technique that we use is just structural magnetic resonance imaging and that allows us to look at the processing modules of the brain – the cortical thickness – the computers that are on the surface of the brain and how much or little of that you have on the surface of the brain. Those are the three main techniques that I use. There’s functional imaging, fMRI, that most people have heard of where you’re looking a blood flow, as well. Those are ways that we measure brain structure and function and this gives us the ability to do scientific measures that then we can correlate to behavioral measures in psychology.

Audrey Hamilton: Does being highly creative mean you’re also more intelligent?

Rex Jung: Not necessarily. There’s a controversy about this in the psychological literature and some people have found correlations between creativity and intelligence. They’re usually pretty low, this association. And some people make a lot of that, this low association. But usually, because this association between creativity and intelligence is low, it means that you don’t necessarily have to be intelligent to be creative. So, I spent over a decade studying intelligence. It’s one of the reasons I started studying creativity because it seemed like something distinctly different and interesting than intelligence, which I have studied. I work with very highly intelligent people in academia and scientists and not all of them are creative. Why is that? If they do go together I would be working with all of the creative people in my city in Albuquerque, but that wasn’t the case so creativity seemed to be something different.

Audrey Hamilton: Can a person learn to become more creative or simply gain intelligence?

Rex Jung: There are some tools and techniques that can help people to be more creative. We’re starting to learn more about creativity and it’s one of the things that I’m excited about in terms of creativity is that there might be ways to increase your creative capacity.

Intelligence unfortunately seems to be much more under tight genetic control. The genetic correlates of intelligence are high, like .75. So, if you have twins – they’re going to be identical twins – their correlation of their intelligence with one another is going to be very, very high. So that implies that the genetic involvement of that capacity is under much more tight control than the environment would be.

With creativity, we don’t have that information and I’m hopeful that you can modulate or modify creative cognition much more than intelligence. There are studies out there that have shown increases in intelligence scores of two, maybe three points on a particular measure, which are not particularly high. But those are also controversial. Some have been replicated. Some haven’t been replicated. And we really don’t see that in terms of intelligence. With creativity, there’s a pitched effort to try to increase creativity scores on some of these measures and we’re seeing some good initial results and I’m very hopeful about that.

Audrey Hamilton: How does the way a person’s brain works and is structured influence how creative or intelligent he or she is?

Rex Jung: The research that we’ve done shows that the brain organization of intelligence and creativity are quite different. So, when you think about those measures that I talked about, those neuroimaging measures, the brain of someone who is intelligent – think of bigger, better, stronger, faster – all the measures are pointing to higher integrity of the brain of someone who has high intelligence. So, the cortical mantle is thicker, the white matter, the wires are more myelinated, the water can travel faster and in a coherent direction, you have more of these certain chemicals that I was talking about.

crAudrey Hamilton: It’s beefed up.

Rex Jung: It’s beefed up, yes. So you can have a better organized brain.

With creativity, the story was different. In different regions of the brain, we were seeing weaker connections, thinner cortex and different levels of these same biochemicals. So, it was really clear from these studies that intelligence and creativity were different because we were seeing different pictures in the measures we were taking of the brain. But I tend to look at creativity and intelligence as two different kinds of reasoning. That creativity is kind of reasoning without all of the information present. So, call it abductive reasoning. But, you have hypothesis testing about how the world could work without all of the information present. So, you have to use abstraction and metaphor and stuff like that about this might look like this or this might be this way.

With intelligence, you’re using deductive reasoning, where it’s rule-based reasoning where a equals b and that’s the way it goes. You have a rule for how this relationship works. So, creativity and intelligence are probably different types of reasoning. Both are very adaptive, but they’re just different for different types of problems that you have to solve out in the world.

Audrey Hamilton: Is real creativity rare? How about genius?

Rex Jung: So, creativity is common and genius is a lot more rare than we would believe. The term genius gets thrown around a lot. But, I think genius is rare because that combination of brain organization where you have high fidelity, beefed up brain in certain regions and then kind of down regulated brain in other regions is really going to be kind of rare where that is present in the same brain. So, to have that back and forth between intelligence and creativity, the ability to do both of those reasoning processes well, where you can do first approximations, hypothesis testing, abstraction and then create a rule, a novel and useful rule out of nothing before is rare and that is true genius.

Audrey Hamilton: Well great. Thank you so much for joining us, Dr. Jung. It’s been very, very interesting.

Rex Jung: Great. Thank you, Audrey.