Mindfulness Disposition and Neural Correlates of Emotional Perception

Mindfulness disposition, defined as the ability to focus on present moment experiences, has been associated with enhanced attentional and emotional control. In this study, we examined if higher levels of mindfulness disposition in older adults were associated with the corticosubcortico circuitry involved in emotional processing. Forty-four participants (25 older adults, 19 younger adults) performed an emotional perception task inside the scanner, and filled out questionnaires related to overall health and mindfulness disposition. Consistent with previous research, we found older adults to show increased recruitment of the prefrontal cortices, specifically the medial prefrontal cortices (mPFC) while processing negative, relative to neutral information. Mindfulness disposition was found to be associated with the neural regions supporting emotional perception. Higher levels of mindfulness disposition in older adults were associated with diminished reactivity of the orbitofrontal cortex and amygdala during the affect block, thus suggesting one pathway through which mindfulness training may enhance emotional regulation. Overall, our results indicate that mindfulness disposition may optimize the neural circuitry associated with emotion perception in older adults. MINDFULNESS DISPOSITION AND NEURAL CORRELATES 3 Mindfulness Disposition and Neural Correlates of Emotional Perception Old age is typically accompanied by bodily deterioration, increasingly frequent health problems, mobility losses, and memory failures (Carstensen, Fung, Gross 1998; Buckner, 2004; Dennis & Cabeza, 2008). One would imagine that with all these hardships older adults are more emotionally distraught than young adults. However, despite the health, social, and psychological difficulties that accompany old age, older adults are emotionally well-adjusted (Carstensen, Pasupathi, Mayr, & Nesselroade, 2000). Additionally, they have been shown to focus more on the emotional meaning of information and how an experience makes them feel (Mather & Carstensen, 2005) than do young adults. In fact, research has shown that high levels of affective well-being and emotional stability are typical in older adults (e.g., Carstensen et al., 2000; Charles, Reynolds. & Gatz, 2001; Kessler & Staudinger, 2009; Kunzmann, Little, & Smith, 2000; Mroczek & Kolarz, 1998; Teachman, 2006). Multiple theories have been proposed to explain why aging is accompanied with this surprising increase in emotional well-being. One such theory is the socioemotional selectivity theory (Carstensen, 1993), which suggests that older adults may be more focused on optimizing their emotional experience than young adults because older adults are closer to the perceived end of life than young adults. This change in time perspective is believed to lead to an increased emphasis on emotional goals and emotional content of information (Carstensen, Fung, & Charles, 2003). Alternatively, the life-span theory of control suggests that the capacity to control one’s environment declines with age (Heckhausen & Schulz, 1995). As a result, older adults are less likely to attempt to change their environment and situations and are more likely to instead adjust their self-views through emotion regulation in order to adapt to the situation (Heckhausen & Schulz, 1995; Heckhausen, Wrosch, & Schulz, 2010). Despite MINDFULNESS DISPOSITION AND NEURAL CORRELATES 4 variation in these proposed theories explicating older adults’ enhanced affective functioning, it is clear that emotion regulation plays a crucial role in aging. Emotion regulation is defined as “the process by which individuals influence which emotions they have, when they have them, and how they experience and express these emotions” (Gross, 1998a, p. 275). It also refers to the ability to exert control over emotional responses. Research suggests enhanced affective functioning and superior emotion regulation in the elderly (Ochsner & Gross, 2005). Blanchard-Fields (2007) posits that this global improvement in regulation in older adults may be related to an advanced ability to adapt regulation strategies according to the stressor. In order to better understand these age-related differences in emotion regulation capabilities, it becomes essential to examine the underlying neural mechanisms involved in emotional processing. While a multitude of brain regions are involved in the neural processing of emotionally salient events (Phan et al., 2002), the automatic processes of the amygdala and controlled processes of the prefrontal cortex (PFC) are among the most critical. The amygdala, a region of the limbic system is a main player in the processing of social-emotional stimuli (Adolphs, 2003; Baron-Cohen, 2003; Brothers, 1990). This subcortical structure is responsible for the automatic detection of emotions as well as the generation of corresponding physiological responses. Functional imaging studies (Irwin et al., 1996; Morris et al., 1996) demonstrate amygdala activation during the processing of threatening stimuli (LeDoux, 1995, 1996) specifically with the left lateralized amygdala putatively playing a special role in the detection of arousing stimuli (Glascher & Adolphs, 2003). Alternatively, the PFC is responsible for the controlled processes involved in processing emotionally salient events. The PFC is primarily involved in the exertion of modulation and control over emotions (Ochsner & MINDFULNESS DISPOSITION AND NEURAL CORRELATES 5 Gross, 2005), with medial and lateral sub-regions supporting different neural processes. The medial PFC (mPFC) coordinates the generation and regulation of affect (Phan, et al., 2002) and has been implicated in tasks involving ‘mentalising’ (Frith & Frith, 1999, 2003), which involves the perception of others’ emotions (Baron-Cohen, 2003; Castelli et al. 2002; Castelli, Happe, Frith, & Frith, 2000). The lateral PFC (lPFC) plays a role in the integration of cognitive and emotion information (Ekman & Davidson, 1994; Dalgleish, & Power, 1999; Martin & Clore, 2001) and is therefore thought to be related to the controlled processes that contribute to