PITTSBURGH, Nov. 6 – A new study suggests that genetic factors influence size variations in a certain region of the brain, which could in turn be partly responsible for increased susceptibility to alcohol dependence.
It appears that the size of the right orbitofrontal cortex (OFC), an area of the brain that is involved in regulating emotional processing and impulsive behavior, is smaller in teenagers and young adults who have several relatives that are alcohol dependent, according to a study led by Dr. Shirley Hill, Ph.D., professor of psychiatry, University of Pittsburgh School of Medicine.
In the research, which was published this week in the early online version of Biological Psychiatry, Dr. Hill and her team imaged the brains of 107 teens and young adults using magnetic resonance imaging. They also examined variation in certain genes of the participants and administered a well-validated questionnaire to measure the youngsters' tendency to be impulsive.
The participants included 63 individuals who were selected for the study because they had multiple alcohol-dependent family members, suggesting a genetic predisposition, and 44 who had no close relatives dependent on drugs or alcohol. Those with several alcohol-dependent relatives were more likely to have reduced volume of the OFC.
When the investigators looked at two genes, 5-HTT and BDNF, they found certain variants that led to a reduction in white matter volume in the OFC, and that in turn was associated with greater impulsivity.
The 5-HTT is a transporter gene for the neurotransmitter serotonin. The gene has been linked to depression, hyperactivity, and disruptive behavior in boys. Low levels of BDNF, or Brain-derived neurotrophic factor, have been linked to assorted problematic cognitive phenomena as well. So a role for these genes in influencing the degree of impulsivity is plausible.
If you pride yourself in your self-control don't feel too smug about the wisdom of your free will in choosing to be so controlled. You probably just have a large right orbitofrontal cortex due to getting genes that code for a large right OFC.
|Share |||Randall Parker, 2008 November 10 10:07 PM Brain Addiction|