I submitted this article as a response to CGS609A (Cognitive Neuroscience) assignment.

We shall attempt to summarize our understanding of a study that attempts to study ‘emotion.’ Humans display a myriad of emotions over the day and throughout their lives. This particular study 1 attempts to redefine the traditional view of neural circuitry and proposes to address a few issues that previous studies missed out.

Let us first try to define ‘fear’ and ‘anxiety’ to have a shared framework that we can base our arguments on later on. Fear is a subjective feeling when faced with imminent danger, such as a lion attacking or a car accident. On the other hand, we define anxiety as the uneasy feeling that one experiences thinking about future events such as the possibility of facing a lion, getting into a car accident, or getting an F grade. For this article, we shall use the two terms interchangeably.

Traditional studies proposed that we have a fear center centered around the amygdala. 2 This hypothesis relies on several key observations. First, when faced with threats, people lacking the amygdala fail to react appropriately. Second, various neuro-imaging techniques revealed that people’s amygdala region gets activated when faced with threats, suggesting activities in the region. People who reported having anxiety disorders showed higher levels of activities in the amygdala region. 3 4

With all this progress made in studying emotions from the neurological viewpoint, the research did not translate to substantial clinical success. Many companies deemed the probability of arriving at a new drug based on these findings meager. As such, investments toward obtaining a breakthrough drug is declining rapidly.

The study in question attempts to mitigate these challenges and proposes an alternative viewpoint, a new framework where a part of the neural circuitry controls how we feel when faced with danger but has no control over our reactions. Another circuit controls how we respond to threats. In short, we do not have a unified ‘center of fear,’ but two separate circuits for different tasks. 1

The proposal in the study relies on previous work done in this area. For all the evidence pointing toward the amygdala region being the center of everything 3, some observations suggest otherwise. First, measurements of physiological responses do not correspond with subjective feelings of fear and anxiety. 5 If there was a fear center which controls everything, then the two must correlate perfectly. However, in practice, this is not the case. Second, people can still get panic attacks, fear, and anxiety issues, even if their amygdala is damaged. 6 Third, people can still show physiological responses even if they report not feeling fear or anxiety, subjectively. 7

The study puts forth two paths that we can follow to improve therapeutics for treating fear and anxiety disorders. Each of these paths complements the other, and when armed with the knowledge of different neural circuits, these can help us deliver better drugs to treat these disorders.

The first approach is to bring in our knowledge from other domains to existing treatments, which can improve the performance of current treatment methods. For example, basic science about animal extinction could prove useful in Cognitive Behavioral Therapy (CBT). 8

The other somewhat obvious approach is to design different treatments for specific cases. The second way would have been immensely challenging a decade or two ago. With the advancement of technology and laboratory methods, it is possible to perform tests and measurements faster, with better accuracy. Advancements in technology can significantly aid our efforts in personalizing treatments for each patient.

With all its promises, the study lacks empirical evidence. It is not clear if this new framework will translate to better therapeutics. To see if the hypothesis proposed in the study work in real life, we can manufacture new drugs and test them. Doing so would help us evaluate the correlation between the center, which allows us to feel fear, and the other circuit that aids our physiological reactions. However, since the feeling of mental well-being is subjective, evaluating effectiveness would be a challenge.

As with other studies in the field, this study also suffers from testing on animals and applying findings to the betterment of humans. Treating mental health disorders and maintaining the overall emotional well-being of a person should be of utmost importance. However, because laboratory findings did not translate to clinical success, progress on this front has been stalled. The study suggests a new path forward.

References

  1. Joseph E. Ledoux and Daniel S. Pine. Using neuroscience to help understand fear and anxiety: A two-system framework. American Journal of Psychiatry, 173(11):1083–1093, 2016.  2

  2. M Davis. The role of the amygdala in fear and anxiety. Annual Review of Neuroscience, 15(1):353–375, 1992. 

  3. Michael J Kozak and Gregory A Miller. Hypothetical constructs versus intervening variables: A re-appraisal of the three-systems model of anxiety assessment. Behavioral assessment, 1982.  2

  4. Peter J Lang. Fear reduction and fear behavior: Problems in treating a construct. In Research in psychotherapy conference, 3rd, May-Jun, 1966, Chicago, IL, US. American Psychological Association, 1968. 

  5. Rachman and R Hodgson. I. synchrony and desynchrony in fear and avoidance. Behaviour research and therapy, 12(4):311–318, 1974. 

  6. Adam K Anderson and Elizabeth A Phelps. Is the human amygdala critical for the subjective experience of emotion? evidence of intact dispositional affect in patients with amygdala lesions. Journal of cognitive neuroscience, 14(5):709–720, 2002. 

  7. Raymond J Dolan and Patrick Vuilleumier. Amygdala automaticity in emotional processing. Annals of the New York Academy of Sciences, 985(1):348–355, 2003. 

  8. Joseph E LeDoux. Anxious: Using the brain to understand and treat fear and anxiety. Penguin, 2015.