Alcohol Damages White Matter In Brain, Affects Critical Thinking

Chronic misuse of alcohol results in measurable damage to the brain. A new study uses high-resolution structural magnetic resonance (MR) scans to compare the brains of individuals with a history of alcoholism versus those of healthy light drinkers.The abstinent alcoholics showed pronounced reductions in frontal and superior white matter tracts.

Chronic misuse of alcohol results in measurable damage to the brain. Chronic drinking may be particularly damaging to the integrity of frontal white matter tracts, which can interfere with cognitive and inhibitory control that, in turn, is important to achieve and maintain abstinence. A new study has used high-resolution structural magnetic resonance (MR) scans to determine the brain's regional vulnerability to chronic alcohol abuse, finding that abstinent alcoholics have reductions in white matter pathways across the entire brain.

"The brain is usually divided into two broad kinds of tissues: gray matter or cortex consisting of neurons, the critical cells that support brain function; and white matter, the connections among large groups of those cells," explained Fortier. "We now know that alcohol impacts both gray and white matter, with the greatest impact affecting parts of the brain called the frontal lobes. These brain areas are critical to learning new information and, even more importantly, in self-regulation, impulse control, and the modification of all complicated human behaviors. In other words, the very parts of the brain that may be most important for controlling problem drinking are damaged by alcohol, and the more alcohol consumed, the greater the damage."

Frontal white matter tracts are the pathways that connect the frontal lobes to the rest of the brain, added Fortier. "The frontal cortex is the integration center for all other parts of the brain that are important to behavior and cognitive function," she said. "These pathways support self-monitoring, planning, judgment, and reasoning. Frontal pathways also allow flexibility in learning and memory, and allow us to change and learn new patterns of behavior. Most importantly, frontal pathways underlie impulse control, which is essential to achieve and maintain abstinence."

Fortier and her colleagues assessed global and regional white matter (WM) microstructure in two groups (n=51) using diffusion MR measures of fractional anisotropy (FA) to create a three-dimensional measurement of white matter tissue: 31 abstinent alcoholics (20 men, 11 women) with an average of 25 years of abuse and approximately five years of sobriety, and 20 nonalcoholic control participants (13 men, 7 women). Study participants were recruited by way of flyers and newspaper advertisements; the mean age of the alcoholic group was 51, and the control group was matched to the alcoholic group with regard to gender, age, education, and estimated intelligence.

"There were two key findings to our study," said Fortier. "First, recovered alcoholics showed reductions in white matter pathways across the entire brain as compared to healthy light drinkers. This means that the pathways that allow the different parts of their brains to communicate efficiently and effectively are disrupted by alcoholism. Second, the effect of alcohol on the brain appears to be dose specific. Pathology is often thought of as occurring as an all-or-none phenomenon--you either have brain damage or you don't, similar to a stroke. Alcohol, however, is more like sunburn. Our study shows that the damage occurs as a function of quantity and exposure; the more you drink, the greater the damage to key structures of the brain, such as the inferior frontal gyrus, in particular. This part of the brain mediates inhibitory control and decision-making, so tragically, it appears that some of the areas of the brain that are most effected by alcohol are important for self-control and judgment, the very things needed to recover from misuse of alcohol."

Heavy alcohol consumption has been associated with brain atrophy, neuronal loss, and poorer white matter fiber integrity. However, there is conflicting evidence on whether light-to-moderate alcohol consumption shows similar negative associations with brain structure. To address this, we examine the associations between alcohol intake and brain structure using multimodal imaging data from 36,678 generally healthy middle-aged and older adults from the UK Biobank, controlling for numerous potential confounds. Consistent with prior literature, we find negative associations between alcohol intake and brain macrostructure and microstructure. Specifically, alcohol intake is negatively associated with global brain volume measures, regional gray matter volumes, and white matter microstructure. Here, we show that the negative associations between alcohol intake and brain macrostructure and microstructure are already apparent in individuals consuming an average of only one to two daily alcohol units, and become stronger as alcohol intake increases.

Alcohol use is typically initiated during adolescence, a period known to be critical in neurodevelopment. The adolescent brain may be particularly susceptible to the harmful effects of alcohol. While the cognitive deficits associated with alcohol use during adolescence have been well-documented, the neural substrates underlying these effects remain inadequately understood. Cerebral white matter has been suggested as a primary site of alcohol-related damage and diffusion tensor imaging (DTI) allows for the quantification of white matter integrity in vivo. This review summarizes results from both cross-sectional and longitudinal studies employing DTI that indicate that white matter tracts, particularly those thought to be involved in executive functioning, continue to develop throughout adolescence and into adulthood. Numerous DTI studies reveal a positive correlation between white matter integrity and neurocognitive performance and, in adults, the detrimental effects of prolonged alcohol-dependence on white matter integrity. We provide a comprehensive review of the DTI studies exploring the relationship between alcohol use and white matter integrity in adolescents. Results from most of these studies suggest that alcohol use is associated with reduced white matter integrity, particularly in the superior longitudinal fasciculus (SLF), and some evidence suggests that this relationship may be influenced by sex. We conclude by highlighting confounds and limitations of the available research and suggesting directions for future research.

The regions of the brain important for judgment, critical thinking and memory do not fully mature until a person is in his or her mid-20s. Tapert found that alcohol can damage the normal growth and development of a teenager's brain cells in these regions.

Psychological studies have students who exhibit signs of binge drinking (consuming four to five drinks per social event) had a harder time remembering events and did more poorly on memory tests than students who have never consumed alcohol. Another observation showed that gender played a part in the effects of alcohol on the teenage body. For example, girls who had abused alcohol seemed to struggle more with critical thinking involving mathematical functions, whereas boys who drank struggled up to 10% more with focusing and paying attention.

More than 30 years ago, my colleagues and I described this syndrome as white matter dementia. In this condition, the dysfunctional white matter is no longer adequately performing as a connector, meaning that the gray matter cannot act together in a seamless and synchronous manner. The brain, in essence, has been disconnected from itself.

Brain damage from drug or alcohol abuse can range from minor to severe physical damage. Some of these injuries, such as traumatic brain injury, strokes, and Wernicke-Korsakoff syndrome, can be more persistent. Other common brain injuries include brain atrophy (brain shrinkage) and permanent changes to white matter.

Prenatal exposure to alcohol (ethanol) results in a continuum of physical, neurological, behavioral, and learning defects collectively grouped under the heading Fetal Alcohol Spectrum Disorder (FASD). Fetal Alcohol Syndrome (FAS) is part of this group and was first defined in 1973 as a condition characterized by pre- and postnatal growth deficiencies, facial abnormalities and defects of the . The CNS is particularly vulnerable to the effects of ethanol during prenatal development. Severe exposure correlates with gross morphological abnormalities and an overall decrease in white matter. Mechanisms for how ethanol affects the development of the CNS are complicated, but damage to neural stem cell progenitor pools that give rise to neurons and glia is strongly suspected to be a major factor. Damage to this population of cells at any point during CNS development can result in abnormalities in the formation and maturation of these cells, from the initial differentiation through the maturation of neuronal networks. This damage can lead to a wide variety of cognitive deficiencies, functional impairments, and behavioral problems depending on the area of the brain impacted by prenatal ethanol exposure.

Long-term heavy drinking affects the frontal lobe functions of the brain, particularly inhibition, decision-making, problem-solving, and judgment. This sort of brain damage makes it difficult for alcoholics to remain sober in the long run.

Alcohol and drug use are particularly damaging to the white matter of the brain, meaning that the efficiency of information flow is compromised. In particular, substance use results in lower white matter volume and disorganization of white matter structure.

The precise mechanisms of alcohol-induced alterations in brain development remain unclear, but studies have identified a number of short-term consequences of alcohol use. Among the most impactful of these consequences are reductions in white matter and grey matter in areas of the brain that regulate the reward system and executive functions. In addition, the integrity of white matter and synaptic connectivity is reduced in adolescents who use alcohol regularly. 2b1af7f3a8