Cerebral Hemispheres 2
NEUROSCIENTIFICALLY CHALLENGED

NEUROSCIENCE MADE SIMPLER

Unseen Drug Cues Can Still Induce Cravings


People generally look at addiction in one of two ways. Some understand the extreme difficulty inherent in battling a craving, whether it be for drugs, food, cigarettes, etc. This is especially the case with those who have experienced addiction, and to a lesser extent with those who have helped someone else through it or studied it extensively. Others may attribute addiction to a personal choice, as if a drug user is able to simply sit down and decide whether or not he or she wants to do drugs today, and then acts on that decision.

The science doesn’t support the latter view. A number of neuroimaging studies demonstrate abnormal activity in the brains of drug addicts. This aberrant activity can involve decision-making areas (pre-frontal lobes), areas correlated with compulsive behavior (anterior cingulate and orbitofrontal cortices), and reward processing centers (mesolimbic dopamine pathway and limbic system). Now consider the genetic influences on tendencies toward addictive behavior and it begins to seem that, if a personal decision is involved, the deck is stacked pretty heavily against an addict making the right one. Drawing an analogy of addiction to personal choice is like telling someone who is clinically depressed they just need to “snap out of it”.

Recent research by a group at University of Pennsylvania has shown addiction to be even more difficult to overcome than previously thought. The group used functional MRI (fMRI) to study brain activity in cocaine-addicted patients as they viewed images with different themes. Some pictures were drug stimuli (e.g. a crack pipe), others were sexual in nature, and the rest were either aversive (i.e. involving pain) or neutral. The images were flashed on a screen for 33 milliseconds, and then immediately followed by another image used to distract the participant and ensure the first picture could not be registered—a technique known as backward masking. Previous studies have shown that this procedure results in participants not consciously recognizing the content of the more briefly displayed image.

The patients exhibited brain activity consistent with drug craving when the drug images were shown, even though the images didn't seem to be consciously processed. This activity occurred throughout limbic structures previously implicated in reward and drug addiction, such as the striatum, amygdala, orbitofrontal cortex, insula, and prefrontal cortex. The activity was similar to that which occurred when the sexual images were viewed.

The Penn research group has hypothesized that the recognition of the drug cues is the result of pure Pavlovian conditioning. According to this view, drug craving becomes a learned reflexive response. With exposure to relevant stimuli, its onset is automatic. The group also suggests that the similarity between how the drug stimuli and sexual stimuli were processed indicates these patients’ brains are viewing drugs in the same way they are viewing biologically rewarding stimuli. Many scientists believe our brains have evolved to view life-promoting goals like procreation and food as rewarding because they are essential to our survival as a species (thus the desire to achieve them was naturally selected for). It seems drugs can hijack the brain’s reward circuitry and convince it drugs are as important as the rewards we have been genetically programmed to pursue. This presents a grim picture of addiction. In my opinion, however, studies such as this one are important in coaxing our society to view addiction as a disorder that requires treatment, instead of a social stigma or a behavior that in and of itself necessitates incarceration.

YOUR BRAIN, EXPLAINED

Sleep. Memory. Pleasure. Fear. Language. We experience these things every day, but how do our brains create them? Your Brain, Explained is a personal tour around your gray matter. Building on neuroscientist Marc Dingman’s popular YouTube series, 2-Minute Neuroscience, this is a friendly, engaging introduction to the human brain and its quirks using real-life examples and Dingman’s own, hand-drawn illustrations.

  • An informative, accessible and engaging book for anyone who has even the slightest interest in how the brain works, but doesn’t know where to begin. - Dean Burnett, PhD, author, Happy Brain and Idiot Brain

  • Dingman weaves classic studies with modern research into easily digestible sections, to provide an excellent primer on the rapidly advancing field of neuroscience. - Moheb Costandi, author, Neuroplasticity and 50 Human Brain Ideas You Really Need to Know

  • Reading like a collection of detective stories, Your Brain, Explained combines classic cases in the history of neurology with findings stemming from the latest techniques used to probe the brain’s secrets. - Stanley Finger, PhD, Professor Emeritus of Psychological & Brain Sciences, Washington University (St. Louis), author, Origins of Neuroscience

  • ...a highly readable and accessible introduction to the operation of the brain and current issues in neuroscience... a wonderful introduction to the field. - Frank Amthor, PhD, Professor of Psychology, The University of Alabama at Birmingham, author, Neuroscience for Dummies

BIZARRE

This book shows a whole other side of how brains work by examining the most unusual behavior to emerge from the human brain. In it, you'll meet a woman who is afraid to take a shower because she fears her body will slip down the drain, a man who is convinced he is a cat, a woman who compulsively snacks on cigarette ashes, and many other unusual cases. As uncommon as they are, each of these cases has something important to teach us about everyday brain function.

  • Through case studies of both exceptional people as well as those with disorders, Bizarre takes us on a fascinating journey in which we learn more about what is going on in our skull. - William J. Ray, PhD, Emeritus Professor of Psychology, The Pennsylvania State University, author, Abnormal Psychology

  • A unique combination of storytelling and scientific explanation that appeals to the brain novice, the trained neuroscientist, and everyone in between. Dingman explores some of the most fascinating and mysterious expressions of human behavior in a style that is case study, dramatic novel, and introductory textbook all rolled into one. - Alison Kreisler, PhD, Neuroscience Instructor, California State University, San Marcos

  • Dingman brings the history of neuroscience back to life and weaves in contemporary ideas seamlessly. Readers will come along for the ride of a really interesting read and accidentally learn some neuroscience along the way. - Erin Kirschmann, PhD, Associate Professor of Psychology & Counseling, Immaculata University

  • Bizarre is a collection of stories of how the brain can create zombies, cult members, extra limbs, instant musicians, and overnight accents, to name a few of the mind-scratching cases. After reading this book, you will walk away with a greater appreciation for this bizarre organ. If you are a fan of Oliver Sacks' books, you're certain to be a fan of Dingman's Bizarre. - Allison M. Wilck, PhD, Researcher and Assistant Professor of Psychology, Eastern Mennonite University