Reduced Feelings of Regret and Enhanced Fronto-striatal Connectivity in Elders With Long-term Tai Chi Experience

Zhiyuan Liu; Lin Li; Sijia Liu; Yubin Sun; Shuang Li; Meng Yi; Li Zheng; Xiuyan Guo

Disclosures

Soc Cogn Affect Neurosci. 2020;15(8):861-873. 

In This Article

Abstract and Introduction

Abstract

The current study investigates how long-term Tai Chi experience affects the neural and emotional response to regret in elders. Participants perform the sequential risk-taking task while undergoing functional magnetic resonance imaging (fMRI) scanning. In the task, participants opened a series of boxes consecutively and decided when to stop. Each box contained a reward, except for one which contained a devil. If the devil was revealed, then this served to zero the participant's gain in that trial. Once stopped, participant's gains and missed chances were revealed. Behaviorally, the Tai Chi group showed less regret, reduced risk taking, higher levels of nonjudgment of inner experience and less emotional sensitivity to outcome. fMRI results showed that the Tai Chi group demonstrated stronger fronto-striatal functional connectivity in trials with numerous missed chances. The nonjudgment of inner experience mediated the impact of fronto-striatal functional connectivity on Tai Chi practitioners' emotional sensitivity to outcome. These results highlight that long-term Tai Chi exercise may be effective in alleviating feelings of regret in elders by promoting reduced judgment of inner experience and enhanced emotion regulation through the strengthening of fronto-striatal functional connectivity.

Introduction

Successful aging is an increasing global concern. Depression is prevalent amongst the elders (Rajkumar et al., 2009), and can have a marked impact upon quality of life (Blazer et al., 1991). The cognitive model of depression causally associates it with rumination (Roelofs et al., 2008a, 2008b), which incorporates repetitive, negative, and self-focused thoughts about the past or future (Thomsen, 2006). For example, the relation between rumination and depression was demonstrated in a case-control study which found that elders with depression had increased rumination of negative stimuli relative to healthy controls (Devanand et al., 2002). A reduced capacity to disengage from ruminative thought might be related to a deficit in executive functions, such deficits are widely reported among elders with depression (Blazer et al., 1991; Hays et al., 1997). In addition, rumination is also associated with counterfactual thinking (Spellman and Mandel, 2010; Epstude and Roese, 2017), the comparison between 'what is' and 'what might have been' (Roese, 1994, 1997). Regret, a common negative emotion in daily life, results from the upward counterfactual thinking, i.e. the comparison between 'what is' and the better 'what might have been' (Coricelli et al., 2005; Sommer et al., 2009; Coricelli and Rustichini, 2010). Numerous studies have found that being immersed in regret was harmful to mental health and even could induce mental illness (Markman and Miller, 2006; Chase et al., 2010; Markman and Weary, 2011). For instance, Roese et al. (2009) revealed that regret was associated with late life depression and had a marked negative impact upon quality of life. Moreover, Brassen et al. (2012) found that unsuccessfully aged (i.e. late-life depressed) individuals reported more regret when presented with poor outcomes compared with successfully aged (healthy) individuals. So, intense regret resulting from uncontrollable counterfactual thinking or automatic rumination might therefore be an obstacle to mental health in later life. Accordingly, how to modulate and reduce elders' regret is widely concerned by researchers.

To control regret by reducing rumination might be an effective way to maintain good mental health for older adults. A practical method to lessen rumination is to promote nonjudging, a nonevaluative stance toward inner experiences, which has been identified as a key component of meditation (Teasdale et al., 1995; Coffey et al., 2010). Meditation is associated with increased levels of nonjudging and associated drops in rumination (Jain et al., 2007; Deyo et al., 2009). Long-term meditation training can help individuals to break their habitual ruminative cycle by making them aware of their feelings and thoughts without judging them or getting trapped in them (Roelofs et al., 2008b). Neuroimaging studies show differential brain activation patterns after long-term or short-term meditation training. Novice meditators (short-term meditation training) showed increased activity in prefrontal areas involved in executive processing (Allen et al., 2012; Lutz et al., 2014). For example, Allen et al. (2012) revealed greater prefrontal activation during executive processing within an emotional Stroop task in healthy individuals after 6 weeks of meditation training. Meanwhile, experienced meditators (long-term meditation training) displayed diminished activation in prefrontal regions (Grant et al., 2011; Taylor et al., 2011; Gard et al., 2012). In regard to the different brain activation patterns between novice meditators and experienced meditators, previous studies interpreted this as novice meditators needing to overcome habitual ways of internally reacting to one's own emotions and might therefore show greater prefrontal activation. But for experienced meditators, they might have automated an accepting stance toward their experience (Tang et al., 2015). Thus long-term meditation training may help to suppress regret automatically by improving the ability to not-judge one's own inner experience.

Meditation encompasses a family of complex practices that include mindfulness meditation, yoga, Tai Chi and chi gong. Of these practices, Tai Chi is a popular exercise for older adults in China which combines Chinese martial arts and meditative movements with a kind of yogic relaxation through deep breathing (Sandlund and Norlander, 2000; Wang et al., 2014; Wayne et al., 2014). Compared with other exercises that contain meditation element, Tai Chi is generally recognized as a safe and low-cost complementary therapy and has been proven to improve balance and reduce fall risk in healthy and neurologically impaired older adults (Li et al., 2012; Manor et al., 2013). It has been claimed that Tai Chi connects the mind and the body by incorporating physical, cognitive, social and meditative components in the same activity (Wayne et al., 2017). Previous studies revealed that Tai Chi, as a physical exercise, was an effective method to not only improve health fitness, such as neuromuscular functions, cardiorespiratory system and balance control (Ray et al., 2005), but also to enhance psychological well-being for older adults (Wang et al., 2010).

However, to the best of our knowledge, there is no research in the literature explores the relationship between Tai Chi practice and regret. To fill this gap, the current study (containing a Tai Chi group and a control group) aimed to investigate whether long-term Tai Chi practice is associated with enhanced nonjudgment of inner experience and reduced automatic feelings of regret. We used the sequential risk-taking task which has been shown to be effective in inducing regret (Brassen et al., 2012; Liu et al., 2016 2017; Li et al., 2018). During the task, participants were asked to open a series of boxes consecutively until they decided to stop. Each box contained a reward (gold), except for one that contained an adverse stimulus (devil), which caused the participant to lose all the gold collected in that trial. By using this sequential risk-taking task, researchers found that striatum participated in the processing of regret (Liu et al., 2016, 2017; Li et al., 2018). Specially, Brassen et al. (2012) found that compared with older adults with depression, successful aging showed reduced responsiveness to regret paralleled by autonomic and fronto-striatal characteristics indicating adaptive shifts in emotion regulation. There exists strong anatomical connectivity between striatum and frontal region (Alexander et al., 1986), and the functional connectivity between these brain regions are thought to play a key role in emotion regulation (Ochsner and Gross, 2005; Wager et al., 2008; Lozoff, 2011). For instance, poor emotion regulation observed in depression has been associated with reduced frontal-striatal connectivity (Heller et al., 2009). In the present study, we were interested in whether long-term Tai Chi practice could enhance emotion regulation by improving frontal-striatal connectivity, with a specific focus on regret.

The main focus of current study was to examine the nonjudgment of inner experience and regret in older adults with long-term Tai Chi practice by using the sequential risk-taking task. Behaviorally, we predicted that the Tai Chi group would show greater nonjudgment of inner experience and less regret than the control group. Furthermore, we hypothesized that nonjudgment of inner experience would be associated with reduced emotional sensitivity to outcome in Tai Chi group. At the neural level, in line with previous findings, we predicted striatum would participate in the processing of regret and that the Tai Chi group would show diminished activation in frontal areas when the outcome of a given trial was revealed. Finally, we predicted that the Tai Chi group would show stronger fronto-striatal connectivity relative to the control group and that in the Tai Chi group, increased fronto-striatal connectivity would explain variation in nonjudgment of inner experience.

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