Leonard Kelley holds a bachelor's in physics with a minor in mathematics. He loves the academic world and strives to constantly explore it.
The amygdala (our fear and stress center in brain) is a great way to measure the stress in a human being. This is because evidence shows this to be a primary reactive center, allowing us to be in flight-or-fight mode and so is a primary recipient of sensory data from the thalamus. Like many brain functions, it releases hormones when activated that cause us to respond to a given situation. This can be a spike of adrenaline, increased blood pressure, elevated heart rate, and muscular tension. Because of this connection to the senses, the amygdala has a strong correlation to the emotional and attention-based regions of the brain and so impacts our focus on life (Goleman 52-3, 87; Paulsen 54-5).
The amygdala therefore offers plenty of potential as a measuring stick for mindfulness impact as a treatment option. A part of the problem with stress is its original role for humans. In the past, it was a survival instinct to a physical situation and was usually just a temporary state. Evolutionarily, we have a need to make quick judgments if we are to survive some situations, and one of these is very automated – the flight-or-fight response. Over time, we develop pattern recognition from this and so anticipate future dangers. Anxiety is one of those triggers, and the fear it instilled was useful…in the past. Nowadays, the mental capacity for stress is much higher and so a transition from a predominantly physically based stress to a mental one occurred over the years. And it’s been shown to still impact us physically. This is a result of stress hormones being released as our perception of such events grows. We can literally imagine the stress into reality! This impacts our higher-executive powers and hinders our ability to reflect on the past and anticipate for the future (Goleman 81-2, Paulsen 52-3).
This has been demonstrated many times in scientific studies. In the mid-80s, Bruce McEwen (Rockefeller University) looked at how dominant and non-dominant tree shrews interacted for 28 days in an enclosed space with no distractions lying around. At the end of the duration, their hippocampus (which is tied to memory) was compared to their before state and signs of a decreased region were well as dendrite lengths decreasing. This was possible evidence that stress impacted their mental health. That is a nutty result because we would all agree that stress does impact us by not with such a change to our brain. Something mental caused a physical change to the subject. Marion Diamond (University of California at Berkley) did a similar study but used rodents instead and had a lot of recreational activities for them to do. Their dendrites ended up growing instead of shrinking. This demonstrates the basic idea of how mental activity is impacted by physical conditions. (Goleman 48-9)
The amygdala had to cause this at times if our flight-or-fight response was to kick in. After all, such quick reactions must happen almost automatically to ensure our survival. If we sat there to process it, then the situation could harm us. This demonstrates the amygdala’s ability to bypass the cortex if needed be. This isn’t to say that the cortex is completely helpless nor that the amygdala has the final say: it’s a matter of situational presence. But if the amygdala is inappropriately firing, the cortex stores that memory and builds pattern recognition for a response that really isn’t needed but instead floods your body with stress reactions (Paulsen 56).
Therefore, overriding that programming requires behavioral and exposure therapy, re-learning how we react to certain things. We can train the amygdala to unlearn the responses by repetition. Otherwise, medicative means such as benzodiazepine are also available to dampen the amygdala’s response. However, those are more of a band aid in that we are not addressing the source of the activity. To relearn, neurons need ability to act, and If drugged then how can they do that? It should be noted that selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that seem to allow neurons to relearn and form new connections while chemically addressing amygdala (Ibid).
Stress takes the focus of us and places it onto it. This diversion of attention takes many different forms, including selective bias (choosing our focus), vigilance bias (keeping our focus), allocating bias (changing our focus), goal orienting biases (know the desired result and focus to it), and meta-awareness biases (quality of our focus). All of this seems to be the structure that hold meditative disciplines all in common. We therefore must gain better control over what we pay attention to if any mindful practice focusing on stress reduction is to be successful. We can accumulate the ability to tune out via habitual actions, and our brains already do this well subconsciously. We must be selective in our information process to be efficient and implement action quickly, but the cost is the non-discriminatory nature of the habituation. We need is to consciously be selective to the point that it is a habit and therefore becomes a subconscious action by choice. What we are aiming for is voluntary attention. This involves out brain stem’s reticular activating system, or RAS. When we encounter an event that we have become habituated to, the stimuli engages the RAS and bypasses our normal cognitive functioning. We therefore expect to see some changes in the RAS for those who meditate compared to those who don’t (124-6).
But the RAS isn’t the only region at play when it comes to attention-related activity. Our midbrain’s limbic system is the heart of our emotive attention that leads to our actions. It’s a complex interplay of the amygdala with the prefrontal circuity, the “brain’s executive center.” That amygdala being so closely tied to negative emotions overrides our executive functioning at times, and meditation has been shown to reduce this mutiny of the mind and regain control of the vessel. This seems to be a unique feature of our species, and it may have to do with our prefrontal cortex taking up more of the brain’s top layer than any other species on earth (127).
So what does science have to say about attention and mindful practices? One study done by Amishi Jha (University of Miami) found that meditators practicing mindfulness-based stress reduction (MBSR) had a better ability to select where their attention went to, much like a cocktail party effect one could control. Davidson followed up on this with his dissertation research. In it, he asked people to focus on a visual cue while ignoring a tactile moment, or vice versa. EEG readings on the visual and tactile cortex showed that meditators had better “cortical specificity,” implying that the focusing ability didn’t increase so much as the ability to filter noise increased. In an MIT study led by Catherine E. Kerr, a MEEG was implemented on people who participated in an 8-week MBSR course vs a group who had to wait for the program. Sure enough, mediators had an increase in selecting their focus vs those who had no training (and this could be because of the breathing exercises or the body scanning). It would seem as though meditation takes the difficult process of maintaining attention and finds ways to make it more sustainable (129-132).
One study by David Creswell (Carnegie Mellon University) had participants with no background experience engage in a 3-day course on mindfulness. The stated goal was to get rid of their drama and in the attempt to do this, the dorsolateral prefrontal area had an increase in activity, trying its best to engage the default network. After the three-day trial, connections between the dorsolateral prefrontal area and the post cingulate area. In a 2009 study by Emory University, a control group was compared to a 3+ year group of mediators and their default area was measured. People with more experience had a decrease in activity for that region of the brain and so were more focused on solving their goals (155-7).
A study by Phillippe Goldin and James Gross (Stanford University) examined MBSR and its effects on stress reduction. They looked at people with a history of social anxiety disorder and gave them an 8-week MBSR training course. MRI scans of their brains were taken prior and after the training, specifically when the individuals were asked about stressful situations. One was given the option to either to distract themselves with mental math or use the MBSR techniques they acquired. The only one which decreased activity in the amygdala was the MBSR (85)
MBSR is not the only tool at our disposal. Alan Wallace developed Mindful Attention Training, or MAT. It focusses on breaking up your mind processes to see how your thoughts flow, allowing you to achieve “subtle awareness of awareness itself.” To see the effectiveness of the program, a study at Emory looked at people with no meditation experience and split them into three groups. One received MAT, another compassion meditation, and a third was a control. Each went along their paths for 8 weeks, and scans were taken of their brains being subjected to emotional imagery prior and post treatment. The MAT group saw the greatest reduction in amygdala activity out of the three (86-7).
Another useful metric for mindful studies is the Trier Social Stress Test or TSST. It simulates socially stressful events and gauges a person based on their response. In one study conducted by Alan Wallace and Paul Ekman, a renewal program for teachers was examined which incorporated psychological training as well as mediation. The TSST was given to the teachers, then a math test. Hypothetically, the stress would impact their performance and could be measured as a time component of blood pressure changes. Comparisons were made with teachers compared to the amount of meditation they received, and as the hours of meditation one had had increased, the time for blood pressure recovery decreased (95-6).
In another study, Davidson looked at Vipassana meditators with over 9,000 hours of meditation. He had them meditate for 8 hours, then apply the TSST the next day. As a part of the stress-inducing events, violent imagery was used. Overall, the amygdala showed lower activity, implying they were “immune to emotional hijacking” as compared to non-meditators. Also interesting was their stronger connections between the amygdala and prefrontal cortex. In fact, the researchers found that an inverse relation held with the strength of the connection and the reactive rates. It was so strong a correlation that it was possible to predict the reaction based off the connection itself. People with more than 30 hours of MBSR training were given the same experiment and no such increased connection was spotted for them. The short term vs. long term benefits of medicating and mindfulness are clear. The results also indicated the individual’s perception of stress was lower than non-mediators, which is really the main goal here. Put things into their proper perspective and results follow (96-7).
And then there is rebreathing techniques and mindfulness. Research has shown this simple action causes the amygdala to lower its activity, probably because of the slow approach to the technique. Adrienne Taren in 2012 looked at people who are mindful but have stress in their lives. People were split into different groups, with the first group was people who didn’t meditate but has “mindfulness as a personality trait” and a second group who had high stress levels. People in the first group had smaller amygdala than those in the second, pointing to an active monitoring leading to a smaller stress center. But Adrienne wasn’t done, wondering if “people who aren’t mindful by disposition rewire their brains to become less reactive to stress.” (Paulsen 56-9)
So a group of high stress people with no employment were sent on a three-day retreat. Half were given relaxation techniques with the other half received MBSR program. After the three days, the amygdala of the MBSR crowd were smaller than the others. Mindfulness seemed to “make their brains more resistant to stress.” In fact, further research has shown how mindfulness leads to a decreased connection between the amygdala and the anterior cingulate cortex, a frontal region in charge of decision making as well as attention. What does this mean? Simply, it’s a breakdown between the “stress center from the logic center,” with emotional influenced being reduced (59).
We can control what our brain does to us, people. We need to implement many different techniques across several disciplines to give ourselves a broad toolset for combating stress and attentional dilemmas. Once we can start such a practice make sure you keep it up so that your neural circuity can be revamped. You will be able to choose how you react to situations. Then, you will no longer be a slave to the distresses of anxiety.
Goleman, Daniel and Richard J. Davidson. Altered Traits. Penguin Random House, New York. 2017. Print. 52-3, 81-7, 95-7, 124-128, 155-7.
Paulsen, Barbara. “Make Peace with Your Anxious Brain.” Mindful. Apr. 2019: 52-59. Print.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2020 Leonard Kelley