Here are more highlights from the presentation:
Combining in vivo brain imaging and animal research allows for an unprecedented examination of underlying mechanisms of damage.
"Alcohol dependence follows a longitudinal course," explained Harper, "from initiation to development of dependence, maintenance, withdrawal, and more often than not, a return to drinking. Throughout this course, the brain undergoes significant biochemical and structural modifications, some for the better and some for the worse, depending on when an individual is studied. Because human alcoholics cannot be forced to drink or not, researchers have no control over when in their course an alcoholic can be studied in the laboratory. By contrast, animal models of alcohol dependence can be exquisitely controlled, in terms of alcohol-exposure amounts, time in development of exposure, withdrawal, nutrition, and the like. When we combine the two approaches, we then have a means of translating knowledge about the change in the condition of the brain from the clinic to the laboratory and back to the clinic."
Both gene and protein changes can occur in the brains of alcoholics.
"Even after death, tissues can reveal the secrets of diseases," said Harper. "For this research, brain tissues were obtained, with ethical consent, from autopsies on alcoholic subjects. Scientists used modern molecular techniques to study the control mechanisms (genes) and building blocks (proteins) of the main component of white matter – the myelin. They found that the expression of genes that control the manufacture of structural proteins of the myelin was reduced in the alcoholic cases. In addition, the content of these proteins in the white matter was reduced. These changes likely alter the structure and function of the myelin sheath and ultimately the conduction of nerve impulses."
It is important for people who abuse alcohol to realize that some of the damage can be reversed.
"Neuropsychological studies have shown that some brain functions improve with abstinence," said Harper. "Although working memory, postural stability, and visuospatial ability may continue to show impairment for weeks to months with sobriety, with prolonged sobriety these brain functions can show improvement."
Some alcoholics can achieve long-term abstinence in spite of persistent deficits in decision-making.
"There is accumulating evidence that the generalized inherited vulnerability to alcoholism and other addictions involves abnormalities of the brain systems that process rewards and punishments," said George Fein, president of and senior scientist at Neurobehavioral Research, Inc., and one of the symposium co-presenters. "People with an inherited vulnerability to addiction, including alcoholism, are much more affected by immediate than delayed rewards.
"A hallmark of addictive substances is that they provide an immediate reward in the intoxicating experience. When actively drinking, an individual's inhibition processes become impaired and can further contribute to poor decisions and excessive drinking. With prolonged bouts of drinking, dependence may ensue along with neural systems damage, commonly affecting frontal lobe based systems and their functions, which include decision making, inhibition, problem solving, and judgment. This is part of the dynamic course of alcoholism that likely contributes to its maintenance. In the symposium, [we presented] data showing that alcoholics can surmount these impairments in decision making and evaluation of rewards and punishments to achieve multi-year sobriety."
