MedicalResearch.com Interview with:
Ksenija Marinkovic and Lauren Beaton
Psychology Department – College of Sciences Spatio-Temporal Brain Imaging Lab Center for Clinical and Cognitive Neuroscience
San Diego State University
San Diego CA
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: In general, we subjectively perceive our actions to be under our deliberate and voluntary control. However, our results are consistent with other accruing evidence suggesting that a large portion of our behavior is automatic and not accessible to conscious experience. The automatic processing primarily underlies predictable daily routines when we seem to be on an “auto-pilot”. In contrast, situations that are ambiguous or that evoke incompatible response tendencies engage cognitive control which allows conscious override of the preplanned actions and results in flexible behavior. Our study used a multimodal imaging approach that combines perfect time sensitivity of magnetoencephalography (MEG) with structural magnetic resonance imaging (MRI) to investigate spatio-temporal stages of the seamless interplay between automatic and controlled processing. MEG is a highly sensitive method that records magnetic fields generated by the brain’s neural activity in real time.
Young, healthy, participants performed a version of the Eriksen Flanker task, which presents two colored squares on either side of a centrally presented target square that appears after a short delay. Participants are instructed to press a button corresponding to the color of the target square in the middle and to pay no attention to the flankers. Although participants know that the flankers are irrelevant, they are unable to disregard them deliberately. Instead, flankers trigger an automatic preparation to respond. This is particularly apparent on mismatch trials on which the flanker color is misleading and it activates the wrong hand. Target appearance overrides the initial automatic response as the response plan is switched to the other hand to make a correct response. This process reflects recruitment of cognitive control or the decision-making capacity which includes a range of functions such monitoring contextual demands, selecting the correct response, and suppressing an automatic but irrelevant action.
Our multimodal MEG imaging method has allowed us to track the neural response as the brain prepares an incorrect response to flankers and then “switches” motor preparation between hemispheres. This approach makes it possible to investigate the interplay between automatic and controlled processing and dissect decision making as it unfolds.
The addition of a moderate dose of alcohol dysregulates this frontal network involved in motor decision making, which decreases accuracy when response conflict is present and lowers neural activity reflecting cognitive control. Related to this overall decrease, and of clinical importance, is the reduced ability to employ cognitive control to refrain from drinking excessively. However, the underlying patterns of response-switching were preserved under alcohol, suggesting that alcohol primarily induces deficits upstream during decision making and not during executing motor commands.
MedicalResearch.com: What should readers take away from your report?
Response: Our study highlights the interplay between automatic and controlled processing, and how it is affected by alcohol. We tend to believe that our actions are both fully voluntary and deliberate and under our control at all times. However, we find that automatic processing of stimuli happens even when we know it is irrelevant. Cognitive control processes can then be employed to override the automatic response; however, by disrupting strategic processing, alcohol may interfere with goal-directed behavior, resulting in poor self-control.
One relevant application of our data is to the real-world situation of driving. When driving, we usually operate on “auto-pilot”, going through the motions automatically and without much conscious thought. However, occasionally it is necessary to quickly react to changing stimuli. For example, if another car suddenly cuts you off, you need to be able to quickly press on the brakes or change lanes. In other words, you must be able to override automaticity and use cognitive control to safely navigate the situation.
To apply this example to our study, flankers activate an automatic response. Occasionally, the target requires a sudden change in motor response and increased cognitive control. When our participants were intoxicated, they were less successful at making these quick changes between two simple tapping motions – much simpler than the complex series of motions required to drive a car. The cognitive control deficit resulting from alcohol intoxication will impair one’s ability to make quick motor decisions, especially in novel or unexpected situations.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: This type of research can have potential applications in further refinement of brain-machine interfacing in individuals with motor disabilities such as limb paralysis. These indices could be used for fluid decoding of automatic motor planning and moment-to-moment changes in cognitive control of intended motion.
Our lab also has ongoing studies of binge drinkers to investigate lasting effects of heavy drinking on brain function. Overall, in the absence of deficits on behavioral tests, we have found a variety of impairments in neural functions in sober young binge drinkers under high-conflict or emotional conditions. These results correlate with a range of measures of alcohol intake confirming that hazardous drinking is associated with harmful consequences. Further studies could implement this task in binge drinking individuals to examine the degree to which deficits in decision making predict future drinking levels or the likelihood of remission.
MedicalResearch.com: Is there anything else you would like to add?
Response: Direct measures of neural activity are much more sensitive to alcohol than the behavioral measures. Additionally, they allow high temporal sensitivity, allowing us to investigate neural events as they unfold in real time.
When the brain changes its mind: Oscillatory dynamics of conflict processing and response switching in a flanker task during alcohol challenge
Lauren E. Beaton, Sheeva Azma Ksenija Marinkovic
Published: January 12, 2018
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