Representing Representation: Integration between the Temporal Lobe and the Posterior Cingulate Influences the Content and Form of Spontaneous Thought

Abstract

When not engaged in the moment, we often spontaneously represent people, places and events that are not present in the environment. Although this capacity has been linked to the default mode network (DMN), it remains unclear how interactions between the nodes of this network give rise to particular mental experiences during spontaneous thought. One hypothesis is that the core of the DMN integrates information from medial and lateral temporal lobe memory systems, which represent different aspects of knowledge. Individual differences in the connectivity between temporal lobe regions and the default mode network core would then predict differences in the content and form of people’s spontaneous thoughts. This study tested this hypothesis by examining the relationship between seed-based functional connectivity and the contents of spontaneous thought recorded in a laboratory study several days later. Variations in connectivity from both medial and lateral temporal lobe regions was associated with different patterns of spontaneous thought and these effects converged on an overlapping region in the posterior cingulate cortex. We propose that the posterior core of the DMN acts as a representational hub that integrates information represented in medial and lateral temporal lobe and this process is important in determining the content and form of spontaneous thought.

What does (and should) "mind wandering" mean?

“…Understanding the differences between different aspects of experiences can be achieved through the use of multivariate statistical techniques that reduce one's data into various dimensions that can be compared to other measures (such as neural function) to determine whether they share common features or mechanisms. This approach appears to indicate that there are stable features of experience in different samples of participants and, consistent with a family-resemblance account of the mindwandering state, that these features vary in their relation to neurocognitive measures (e.g., Smallwood et al, 2016).…”

“…That said, we argue that assessing these additional dimensions of mind wandering can be exceptionally valuable (e.g., Gorgolewski et al, 2014;Ruby, Smallwood, Sackur, & Singer, 2013;Stawarczyk et al, 2011;Smallwood et al, 2016). For instance, research has suggested that one's level of awareness of mind wandering affects performance on certain tasks, with lower levels of awareness associated with poorer performance than higher levels (Smallwood, McSpadden, & Schooler, 2007).…”

“…Klinger and his colleagues (e.g., Klinger, 1978-79;Klinger & Cox, 1987-88) assessed and defined "fantasy," or "daydreaming," along three orthogonal dimensions of thought: (a) involuntary-undirected-respondent thought versus voluntary-directed-operant thought, (b) fanciful-bizarre versus realistic thought, and (c) stimulus-independent versus stimulus-dependent thought (for a more recent multidimensional approach in the context of neuroimaging, see Smallwood et al, 2016; for a multidimensional approach to the study of daydreaming-related habits or traits, see Singer & Antrobus, 1963). As detailed below, we believe it is now time to reinstate the practice of embracing the rich complexity of the phenomena that we are investigating.…”

“…First, because family resemblances are determined by both common and distinct features, it will be increasingly important to assess multiple features of experience at the same time. This approach, which is common to daily-life investigations of mind wandering (e.g., Kane et al, 2007;Klinger, 1978-79;Klinger & Cox, 1987-88;Song & Wang, 2012), but not used frequently in laboratory studies (but see Smallwood et al, 2016), asks participants to answer multiple experience-sampling probe questions about the contents of their experience, which thereby allows the researcher to identify common and distinct elements of experience. Understanding the differences between different aspects of experiences can be achieved through the use of multivariate statistical techniques that reduce one's data into various dimensions that can be compared to other measures (such as neural function) to determine whether they share common features or mechanisms.…”

A Neural Model of Mind Wandering

“…We argue, however, that it is always necessary to proceed through the proposed off-focus state. Recent research has shown that mind wandering consists of a complex, multi-faceted pattern involving episodic thought, emotion, executive control and meta-awareness in a component process account [36] featuring intricate combinations of corresponding neural responses [37]. Furthermore, intention during mind wandering has recently been identified as a key dimension with great explanatory power [38][39][40].…”