One of the strongest predictors of becoming an alcoholic is family history: the offspring of people with the disorder are four times more likely than others to develop it, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA). But new research shows a family history of alcoholism (FHA) affects more than your desire to drink. It also changes how your brain transitions from one task to the next—going, say, from cooking breakfast to thinking about a work deadline.
A whole line of research has found that having an alcoholic in the family can affect one’s mental processes. But these studies have not fully explored what is called executive function—planning, restraint and other behaviors that are impaired with FHA.
To delve further, Enrico Amico, now at the Swiss Federal Institute of Technology in Lausanne, and his colleagues decided to focus on how the brain processes competing cognitive demands—the switching of neural activity from one brain network to another, which is critical to executive functioning. Prior studies acquired “snapshots” of network activity when subjects were either performing a task or resting quietly. But this approach does not provide a continuous record of what is happening in the brain to capture the dynamic transitions from active to resting states that occur constantly throughout the day. So Amico, then at Purdue University, and a team of researchers at Purdue and Indiana University set out to answer how the brain makes these transitions.
The researchers used a functional magnetic resonance imaging (fMRI) scanner to examine the changes in the brains of 54 participants as they performed a task that required them to indicate the direction of an on-screen arrow by pushing a button or to refrain from doing so in response to a stop signal. Afterward, the subjects were instructed to rest while fixing their gaze on a crosshair on the screen.
The scans showed that individuals without FHA went through a transient period between the game task and the resting state in which some brain regions—frontal, parietal and visual areas, in particular—reconfigured the way in which they communicated with one another. People with FHA experienced fewer changes—even after the researchers controlled for factors such as age, gender, motion in the fMRI scanner, drinking and depression. “It looks like FHA impacts the mental preparation to switch from performing one task to another,” Amico says. “This could be analogous to the process of clearing the cache of your smartphone when you want it to switch faster between apps. The problem is that this ‘cache-clearing process’ might be impaired in brains with family history of alcoholism.”
While a group of 54 participants is a small sample for most studies, Amico maintains it is ample for an fMRI study. “We were very thorough in assessing statistical power and the effect sizes of our claims, so these fMRI results are definitely sufficiently powered,” he says. The study was published last month in NeuroImage.
FHA did not seem to have an impact on participants’ ability to complete the mentally demanding tasks, but deficiencies still may be found in future studies. “What if you are not impaired in doing the task, but then, afterward, you are more stressed or less reactive or even more forgetful or less attentive than a person without FHA?” Amico asks. “This is my hypothesis. And hopefully future studies will tell us more about this fascinating process.” Additional investigations are also needed to answer why people with FHA switch between activity and rest in a different way—and whether there may be a genetic basis for its occurrence.
The ability to switch seamlessly from a relatively demanding task (balancing a checkbook) to a less demanding one (binge-watching a TV show that you have already seen) is critical to going about our everyday activities, explains Reza Momenan, director of the Clinical NeuroImaging Research Core at NIAAA, who was not involved with the research. Carrying out this transition smoothly, Momenan says, helps the nervous system remain in a stable equilibrium state needed for survival. This type of research could provide the basis for better diagnoses for psychiatric disorders than simply interviewing patients to determine the risk, severity or prognosis for alcohol use disorder.
Anita Cservenka, a neuroscientist at Oregon State University, who was also not involved in the research that went into the new paper, found its results to be compelling. “The study’s findings point to important new approaches in understanding neural differences between those with and without a family history risk for alcohol use disorder.”
Cservenka suggests further research might examine whether these task-to-rest neural measures predict the beginning of heavy alcohol consumption or a capacity to avoid drinking. Another possibility, Momenan says, would be to look at the brain activity of people diagnosed with alcohol use disorder, perhaps providing still deeper insight into the mental-processing impact of having an alcoholic in the family.