Cerebral Hemispheres 2
NEUROSCIENTIFICALLY CHALLENGED

NEUROSCIENCE MADE SIMPLER

Epigenetics and Alcoholism


Many of us, even those without alcohol problems, may feel more inclined to have a drink after a bad day, when stress is building up, or when we are trying to take our minds off of something that’s bothering us. This is one of the reasons alcohol is so popular: it has the ability to relieve anxiety and stress, at least while it’s being served (the next morning is another story). It’s also, however, one of the reasons alcoholism is so insidious. For an alcoholic, periods of alcohol withdrawal involve severe anxiety. When in the throes of this angst, it is extremely difficult for an alcoholic to avoid returning to what their brain has identified as the most efficient stress-reducer within their reach. A recent report in The Journal of Neuroscience indicates that this withdrawal anxiety may be due to changes in gene expression.

Previous research has pointed to the importance of a neuropeptide transmitter called neuropeptide Y (NPY) in managing anxiety, and in modulating alcohol consumption. Low levels of NPY, specifically in the amygdala, have been found in animals that have a preference for alcohol. Additionally, knockout mice who are engineered to lack NPY receptors exhibit an increased proclivity for alcohol.

The researchers involved in the current study wanted to determine how fluctuations in NPY occur. They found that NPY transmission in rats is influenced by transient changes in gene expression. These changes, known in biology as epigenetic processes (epi- meaning “in addition to”), involve chemical modifications of DNA that can alter gene expression, but don’t affect the actual DNA sequence of the organism. Thus, the gene expression is somewhat temporary (in that the DNA is not permanently altered), although how long it actually lasts depends on the specifics of the process.

DNA is wound around proteins called histones, and how tightly they are knitted together can affect gene expression epigenetically. There are enzymes that can loosen how tightly they are wrapped up, called histone acetyltransferases (HATs), and those that can tighten the packing, known as histone deacetylases (HDACs). HATs generally promote gene expression, while HDACs inhibit it.

The research team in this study found that exposure to alcohol decreased the activity of the gene inhibitors (HDACs) in rats’ amygdalas, leading to increased gene expression. This expression resulted in higher levels of NPY, and the corresponding low anxiety levels that alcohol is known for. Withdrawal, however, increased HDAC activity, reducing NPY levels, and causing a significant increase in anxiety behavior. When the group administered a drug that blocks HDAC activity, they were able to prevent observable anxiety from occurring during withdrawal.

This suggests that a possible future treatment for alcohol withdrawal could involve pharmaceuticals that inhibit HDACs. Removing the consuming anxiety caused by withdrawal would be a potent tool in the treatment of the disorder. And, studying epigenetic processes may be a fruitful method of finding treatments for addiction in general, as transient changes in brain function (which could be due to gene expression) seem to be involved in many cases.

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.

  • 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

  • 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

  • ...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

  • 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

  • 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