Frontal cortex at center of ability to control impulsive responses, study finds
WEDNESDAY, March 5 (HealthDay News) -- Teens at risk of developing a substance abuse disorder have deficits in frontal brain activation, a U.S. study concludes.
The researchers used functional MRI to study brain activity in 25 participants, ages 12 to 19, as they did an eye movement test. The scientists found a link between increased risk for a substance abuse disorder and shortfalls in executive cognitive function (ECF).
"ECF is basically the control center for governing other cognitive processes," corresponding author Rebecca Landes McNamee, assistant research professor of radiology and bioengineering at the University of Pittsburgh, said in a prepared statement.
"For example, in school, ECF would be engaged in the planning and control process required in answering a question, formulating your response, raising your hand, waiting until you are called upon, and starting your answer. A person with low levels of ECF might blurt out the answer," McNamee said.
"Another example could be interacting with someone on the playground who upsets you. A person with good ECF will think through the actions and consequences of their behavior rather than responding rashly. A person with low levels of ECF may respond with violence."
In this study, the teens did a task that required inhibition of an initial eye movement as well as a voluntary eye realignment to an alternate location. While they did this, fMRI was used to scan activation in different brain regions.
In addition, each adolescent's neurobehavioral disinhibition (ND) -- the ability to control an immediate impulsive response to a given situation -- was assessed, and their drug use/histories were recorded.
"We found that individuals who exhibit a high amount of ND -- that is, do not have a good ability to manage their impulsive responses -- have less brain activity in the frontal cortex, the region of the brain responsible for ECF, during the antisaccade task. In other words, the regions of the brain responsible for these inhibitory processes engaged less energy in individuals with higher ND scores than those with lower ND scores," McNamee said.
One of the key findings of this study, published in the March issue of the journal Alcoholism: Clinical & Experimental Research, is that behaviors and actions are directly related to brain functioning.
"Teachers, caregivers, and other individuals should understand that each adolescent matures at a different rate; they do not always respond like adults, because their brains are not at the same level of functioning as an adult," McNamee said. "Responses and behaviors related to a certain situation are less easy for some adolescents to manage than others."
The Nemours Foundation has more about teens and alcohol and drugs.
-- Robert Preidt
SOURCE: Alcoholism: Clinical & Experimental Research, news release, March 4, 2008
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