Every day of our lives is filled with choices: Do I want coffee today? Which route to work should I take? What am I having for dinner? Will I study tonight, or will I watch a movie? All of these and many more questions come to mind, and we make decisions under the assumption that we will be rewarded of some sort. How do all these decisions come about? Our neural circuits within the brain are so intricately connected and they also connect to the rest of our body.
There are two central decision-making centers largely associated with inference-based decision making and the receiving of rewards: the Orbitofrontal Cortex (OFC) and the dorsal anterior cingulate cortex (dACC). They make cognitive maps, simulate the consequences of decisions, and allow us to evaluate options that we have not encountered before. However, what happens in different bodily states–more specifically when our body is aroused?
Body arousal may include increases in heart rate, respiratory rate, and changes in body temperature. In the research “Interaction between decision-making and interoceptive representations of bodily arousal in the frontal cortex,” scientists study how these different physiological processes affect our cognitive processes and alter our decision-making. Their primary results by observing rhesus monkeys suggest that in states of arousal–specifically heart beating faster–decisions were made faster and fostered better performance. More importantly, they found that a sixth of the neurons in either the OFC and dACC correlated with the fluctuations in heart rate–so if the heart rate increases then the activity of the cells would speed up. The rest of the cells contributed to the overall decision-making process. This suggests that the sole job of some of the neurons is to track the body’s different states. This should make sense since, at higher states of arousal where we may be in danger, we want our body to be able to make decisions faster¬–increasing chances of survival or generating defensive tactics.
The next question then became: how do conditions such as anxiety, addiction, and psychiatric disorders influence decision-making? Since they all portray heightened states of arousal, scientists thought it was relevant to conduct research on this. In relation to this, they included the study of the amygdala. Since the amygdala helps coordinate responses to stimuli that trigger emotional responses, such as fear and danger, researchers surgically turned off the amygdala in each of the animals. What they found was that in higher arousal rates (indicated by a faster heart rate) the animals were slower to choose a reward. Looking at the neural activity, both brain centers had a reduced number of neurons involved in the decision-making process. This suggests that, when analyzing these two brain centers solely, a heightened state of arousal delays the decision-making process. It also corroborates the amygdala’s function of responding to different emotionally stimulating situations.
Overall, the study was able to show that the two main decision-making centers of the brain–OFC and dAAC–have neurons responsible for making decisions specifically when the body is in a state of arousal. It also indicated that a higher state of arousal led to faster decisions made and improved performance. When the body is aroused due to anxiety, addiction, or psychiatric disorders, the decision-making ability is hindered, and neurons respond slower. Moving forward, scientists would like to further study how arousal affects higher brain functions and what its connection is to psychiatric disorders.
References
Atsushi Fujimoto, Elisabeth A. Murray, Peter H. Rudebeck. (2021). Interaction between decision-making and interoceptive representations of bodily arousal in frontal cortex. Proceedings of the National Academy of Sciences, 118 (35): e2014781118 DOI: 10.1073/pnas.2014781118
The Mount Sinai Hospital / Mount Sinai School of Medicine. (2021, August 30). How a racing heart may alter decision-making brain circuits: Body-state monitoring neurons can hijack the decision-making process. ScienceDaily. Retrieved October 21, 2021. www.sciencedaily.com/releases/2021/08/210830140224.htm
Wang, F., & Kahnt, T. (2021). Neural circuits for inference-based decision-making. Current Opinion in Behavioral Sciences, 41, 10–14. https://doi.org/10.1016/j.cobeha.2021.02.004
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