“Hamlet, Prince of Denmark,” considered one of Shakespeare’s best tragedies and perhaps one of the most famous English plays ever written, chronicles the quest of Prince Hamlet to avenge his father’s death through ruminating soliloquies and machinations.
Hamlet, Act III Scene 1: “To be or not to be: that is the question: Whether ‘tis nobler in the mind to suffer The slings and arrows of outrageous fortune, Or to take arms against a sea of troubles, And, by opposing, end them?. . .” (William Shakespeare, circa 1600).
The word ruminate originates from the Latin “ruminatus,” which means “to chew the cud; turn over in the mind.” Cattle, sheep, goats, giraffe, and camels are good examples of ruminant animals.
For this post, however, we are concentrating on the second definition – To turn over in the mind.
What’s in a mind?
Whether a playwright, an artist, a scientist, a parent, or simply being human, rumination is a fairly common mental activity that occurs for most people every once in a while, usually when particularly upsetting situations are being processed. In particular, ruminative thinking can lead to a person being more biased toward negative information, having trouble problem-solving, and sustaining negative mood states.
According to The Recovery Village website, rumination occurs more frequently in women than men and more often in younger people than those over 62. For some individuals though, rumination can occur frequently and is often linked to depression and anxiety. For individuals experiencing depression and/or anxiety in which ruminative thinking is a significant behavior, seeking assistance from professionals is very important.
Researchers are beginning to unravel the complexities of ruminations. For example, not all ruminative thinking is the same, and in fact may be associated with different outcomes. In a recent publication in the Psychonomic Society’s journal, Cognitive, Affective, & Behavioral Neuroscience, researchers Maureen Satyshur, Elliot Layden, Jennifer Gowins, Angel Buchanan, and Jacqueline Gollan, all of the Northwestern University Feinberg School of Medicine in Chicago, explored the neural underpinnings of two types of rumination. The researchers compared brooding and reflective rumination using structural and functional brain imaging techniques and standard scales of rumination and depression.
Rumination can be conceptualized based on the proposed motivation, content, and outcome of the ruminating thoughts. For example, previous work conducted by Treynor and colleagues (2003) indicated that three types of ruminative thinking can be identified based on results derived from a self-report Ruminative Response Scale: depression-related, brooding, and reflective.
As seen in the table below, brooding rumination is characterized as passive and involves people comparing their current situation to some unachieved standard. This type of rumination leads one to be self-critical, overly negative, and focused solely on the problem. Brooding rumination has been linked to current and future depressive symptoms and occurs more often in individuals diagnosed with major depressive disorder (MDD).
In contrast, reflective rumination is considered to be active and solution-centered, in which people turn inward to purposefully examine their current distress from a neutral perspective with the goal of figuring out how to cope with the distressful thoughts and feelings. Yet, even this seemingly healthier version of rumination can still interfere with memories when processing emotional stimuli and can be predictive of brooding rumination. For example, when reflective rumination and brooding rumination are both high, individuals report more severe depressive symptoms under high stress conditions, as reported by Junkins and Haeffel (2017).
Recent neurological investigations have shown that different areas of the brain may be more active during these two types of rumination, which suggests that these two cognitive states may be separate phenomena. Armed with this knowledge, Satyshar and her colleagues decided to investigate this questions more closely in women who did not have any history of depression and women who had a diagnosis of major depressive disorder but had not experienced therapeutic or psychotropic treatment in the two weeks prior to participating in the study. Women were the focus of this study due to the greater prevalence of ruminative thinking in women and their susceptibility to depression.
Ruminating on Brain Areas
Satyshar and colleagues targeted six different areas of the brain that had been implicated in previous neural imaging studies of rumination, or of cognitive tasks involved or implicated in ruminative thinking. The brain image below illustrates the selected areas or “seeds” measured in the current study.
The default mode network (DMN) is composed of two major components highlighted in the image above: the posterior cingulate cortex (PCC) and the medial prefrontal cortex (mPFC).
The PCC (blue area in the brain image above) activates during self-referential and negative autobiographical memory tasks. This area is also associated with episodic memory (memory for personal experiences like the first time you saw Hamlet on stage) and first-person perspective-taking processes (“How would I act in this situation?”) in healthy and depressed individuals. This area could thus be important for both types of ruminative thinking.
The mPFC (red area in the brain image above) activates during self-referential and negative autobiographical memory tasks too, but may be more involved in self-referential thinking (“I am not a revengeful person”) and making judgments about others (“Hamlet was wrong for thinking badly about his mother”). Individuals who are asked to make negative judgments about themselves (“I am a hard person to like”), show greater neural activity if diagnosed with MDD compared to those without MDD.
Another area that has been implicated in self-related thinking is the intrinsic functional connectivity (FC) during a resting state of the DMN. FC is not visually represented in the brain image above as it represents a pattern of neural activation between specific “seeds” that is quantified using a complex equation. Depressed individuals tend to have greater activation of the FC network even at rest, suggesting that the neural activity of depressed individuals is heightened and differs from that of healthy control participants.
Within the FC, two specific areas have been implicated in this increased activation: the rostral (r) and subgenual (sg) anterior cingular cortex (ACC, green area above). These two areas, more broadly viewed as the ACC in the figure above, are involved in integrating emotional information from limbic areas with self-referential information of the DMN. These areas are therefore thought to be associated with increased ruminative thinking, feelings of sadness, and heightened awareness of the negative aspects of incoming information.
The amygdala (center for fear learning and memory; blue and pink areas) was also targeted as a possible area implicated in ruminative thinking. Increased activity in the amygdala is associated with overactive emotional responses and rumination. As part of the limbic system, a more “primitive” or older part of the brain, the amygdala may be involved in the “bottom-up” processing of negative, recurring thoughts.
Finally, the dorsolateral prefrontal cortex (dlPFC, orange area) was targeted due to a possible disruption of functioning in this area. Satyshar and colleagues hypothesized that decreased inhibition from this emotional regulatory region may make it difficult for ruminating individuals to disengage from processing the negative feelings associated with a situation, leading to a continuation of the rumination especially with regard to negative emotional responses. This “top-down” process may be interacting with the “bottom-up” process and mediate the functional connectivity between areas.
So what is inside Pandora’s box?
After co-registering the anatomical and functional scans and processing the 83 individual responses to ruminating thoughts with some neuroimaging processing magic, Satyshar and colleagues found that individuals with MDD and healthy controls showed different types of activation based on the types of rumination they reported.
Specifically, increased brooding rumination was associated with decreased functional connectivity between the left amygdala and the right temporal pole. Satyshar and colleagues argued that this decreased activation may be associated with self-critical and threatening interpretations of emotional stimuli. That is, perhaps the lack of connectivity disrupts the emotional regulation process that is used to regulate negative emotional processing or activity within the amygdala. This reduced connectivity then leads to a tendency for the amygdala and the right temporal pole to be more active thus resulting in brooding rumination.
Reflective rumination, on the other hand, was accompanied by activation in a number of areas, including the PCC, dACC, FC, mPFC, PCC, and occipital pole FC. These findings suggest that the interaction between higher-order cognitive and lower-level affective processes may be part of the neural mechanism behind reflective rumination. If this is the case, then the mechanism may operate so that individuals are able to distance themselves from the negative affect of a situation, which allows them to reflect upon the situation more neutrally and logically. This interpretation is supported by the finding that increased reflective ruminations were associated with a stronger FC between the ACC and the right supramarginal gyrus (rSMG), an area associated with self/other distinctions particularly when it comes to making empathic judgments of others.
“How do you solve a problem, like Maria?”
Whether you are a fan of the musical, Sound of Music, or Shakespeare’s plays, all humans must figure out how to cope with ruminating thoughts. Understanding the neural basis of the different types of ruminations can help us find appropriate coping methods.
The Recovery Village website had several suggestions regarding how to cope with ruminative thinking. For example, if one tends toward brooding ruminations, it might be helpful to work on controlling negative thought processes through cognitive-behavioral therapy or going for a walk in nature where the peacefulness of the wind in the trees, the seasonal flowers, sunlight, and fresh air help to reset the mind. Or, if one tends toward reflective rumination, a walk in nature might be helpful but journaling or talking to someone may be even more helpful in processing the situation fully. Ultimately, we must remember that ruminative thinking occurs in everyday life, but sometimes it needs to be controlled to live a life to the fullest.
Ultimately, as Prince Hamlet reminds his audience:
“There is nothing either good or bad, but thinking makes it so” (Act II, Scene 2).
Psychonomics article focused on in this post:
Satyshur, M. D., Layden, E. A., Gowins, J. R., Buchanan, A., & Gollan, J. K. (2018). Functional connectivity of reflective and brooding rumination in depressed and healthy women. Cognitive, Affective, & Behavioral Neuroscience, 18, 884-901. DOI: 10.3758/s13415-018-0611-7.
