A closer look at the relationship between the default network, mind wandering, negative mood, and depression

Cogn Affect Behav Neurosci (2017) 17:697–711 DOI 10.3758/s13415-017-0506-z A closer look at the relationship between the default network, mind wandering, negative mood, and depression Shaghayegh Konjedi 1 & Reza Maleeh 2 Published online: 7 April 2017 # Psychonomic Society, Inc. 2017 Abstract By a systematic analysis of the current literature on the neural correlates of mind wandering, that is, the default network (DN), and by shedding light on some determinative factors and conditions which affect the relationship between mind wandering and negative mood, we show that (1) mind wandering per se does not necessarily have a positive correlation with negative mood and, on the higher levels, depression. We propose that negative mood as a consequence of mind wandering generally depends on two determinative conditions, that is, whether mind wandering is with or without metaawareness and whether mind wandering occurs during high or low vigilance states; (2) increased activity of the DN is not necessarily followed by an increase in unhappiness and depression. We argue that while in some kinds of meditation practices we witness an increase in the structure and in the activity of the DN, no increase in unhappiness and depression is observed. Keywords Attention . Depression . Cognitive control . Mood . Regulation . Default network . Mind wandering . Meditation Introduction The discovery of the default network (DN hereafter) as the neural correlate of mind wandering has been marked as an important finding in neuroscience. Such a finding is a result * Reza Maleeh 1 Institute for Cognitive Science Studies, Tehran, Iran 2 School of Historical and Philosophical Inquiry, The University of Queensland, Brisbane, Australia of examining rest control conditions during functional imaging studies (Raichle et al., 2001). Now we know that during resting state that the brain performs no demanding task, the activity of the DN increases (Raichle et al., 2001; Raichle & Snyder, 2007). To date, many studies have been conducted regarding mind wandering and its functions. These studies demonstrate that mind wandering is related to both adaptive and maladaptive functions. There have also been informative review articles investigating the relationships between mind wandering and adaptive and maladaptive functions; review articles such as Andrews-Hanna (2012), Smallwood and Andrews-Hanna (2013), Mooneyham and Schooler (2013), and Schooler et al. (2014), to cite but a few. In this article, we particularly focus on one of the important maladaptive functions of mind wandering, that is, negative mood, and conditions under which such a maladaptive function occurs. Apart from adaptive functions attributed to the activity of the DN and mind wandering, which will be addressed briefly in Section 2, evidence shows that under certain conditions the activity of the DN and the occurrence of mind wandering may have an emotional cost, such as creating negative mood. Although the relationship between mind wandering and negative mood is often unclear and complex, there have been several studies which shed light on such a relationship. For example, in a well-received paper by Killingsworth and Gilbert (2010), they claim that mind wandering causally increases negative mood. In this regard, as we will see, generally two different claims have been proposed: (1) there may be a positive correlation between the occurrence of mind wandering and unhappiness or negative mood, and (2) increased activity of the DN can be positively correlated with depression. In this article, by a systematic analysis of the current literature on the structure and functionality of the DN, we examine 698 the relationship between the DN, mind wandering, and negative mood at greater depth. We also argue that none of the above claims can be valid unconditionally. We will try to distinguish conditions under which mind wandering is or is not followed by negative mood. In each case, we investigate the corresponding neural correlates. In doing so, we introduce different and somewhat new factors and conditions which can affect the relationship between mind wandering and negative mood. This may distinguish the present work from previous studies that address the same topic. In Section 3, based on the studies on the neural correlates of mind wandering in opposite states, that is, mind wandering with meta-awareness versus without meta-awareness, on the one hand, and mind wandering during high vigilance versus during low vigilance state (EEG based) on the other, we show that for mind wandering to be accompanied by subsequent negative mood, some other factors and conditions must be taken into play. In Section 4, we argue that some kinds of meditation practices can prevent negative mood despite the presence of mind wandering. More importantly, we show that although some sorts of meditative practices, such as mindfulness-based stress reduction (MBSR), make structural and functional increases in the DN, they are not accompanied by negative mood and depression. Figures 1 and 2 summarize the arguments of this article. Figure 1 illustrates that the occurrence of mind wandering during periods of high vigilance and/or mind wandering without metaawareness leads to more attention and monitoring processes, especially conflict monitoring. These monitoring processes, in turn, increase the likelihood of negative mood. By meta-awareness we mean a re-representation of conscious contents (Braboszcz, Hahusseau, & Miles, 2010; Smallwood & Schooler, 2006), that is, the ability to consider the content of mental state carefully (Smallwood, McSpadden, & Schooler, 2007). Despite the presence of mind wandering during meditation, the absence of conflict monitoring makes it less likely for negative mood to emerge. In other words, meditation can be considered a third state of mind wandering which does not give rise to negative mood. Figure 2 illustrates that frontoparietal control network (FPCN) activity and metacognition can affect the consequence of increased DN activity in terms of negative mood. By metacognition we refer to Bthe ability to reflect upon, comment about, and report a variety of mental states…[or in general] cognition about cognition^ (Fleming, Dolan & Frith, 2012, p. 1280). Metacognition includes a variety of executive functions (Christoff, Gordon, Smallwood, Smith, & Schooler, 2009; Fleming et al., 2012; Fox & Christoff, 2014). It can occur in the absence of meta-awareness (Schooler, 2002). During increased DN activity, metacognitive processes can lead to different consequences. If these processes occur during high vigilance states of mind wandering and/or in the state of mind wandering without meta-awareness, they give rise to negative mood. However, if they occur in the state of meditation, no negative mood or depression arises. Cogn Affect Behav Neurosci (2017) 17:697–711 Default network, mind wandering, their functions and relations Studies on the anatomy (...truncated)