In the past 15 years, mind-wandering has become a prominent topic in cognitive neuroscience and psychology. Whereas mind-wandering has come to be predominantly defined as task-unrelated and/or stimulus-unrelated thought, we argue that this content-based definition fails to capture the defining quality of mind-wandering: the relatively free and spontaneous arising of mental states as the mind wanders.
We define spontaneous thought as a mental state, or a sequence of mental states, that arises relatively freely due to an absence of strong constraints on the contents of each state and on the transitions from one mental state to another. We propose that there are two general ways in which the content of mental states, and the transitions between them, can be constrained.
Deliberate and automatic constraints serve to limit the contents of thought and how these contents change over time. Deliberate constraints are implemented through cognitive control, whereas automatic constraints can be considered as a family of mechanisms that operate outside of cognitive control, including sensory or affective salience.
Within our framework, mind-wandering can be defined as a special case of spontaneous thought that tends to be more deliberately constrained than dreaming, but less deliberately constrained than creative thinking and goal-directed thought. In addition, mind-wandering can be clearly distinguished from rumination and other types of thought that are marked by a high degree of automatic constraints, such as obsessive thought.
In general, deliberate constraints are minimal during dreaming, tend to increase somewhat during mind-wandering, increase further during creative thinking and are strongest during goal-directed thought. There is a range of low-to-medium level of automatic constraints that can occur during dreaming, mind-wandering and creative thinking, but thought ceases to be spontaneous at the strongest levels of automatic constraint, such as during rumination or obsessive thought.
We propose a neural model of the interactions among sources of variability, automatic constraints and deliberate constraints on thought: the default network (DN) subsystem centred around the medial temporal lobe (MTL) (DNMTL) and sensorimotor areas can act as sources of variability; the salience networks, the dorsal attention network (DAN) and the core DN subsystem (DNCORE) can exert automatic constraints on the output of the DNMTL and sensorimotor areas, thus limiting the variability of thought; and the frontoparietal control network can exert deliberate constraints on thought by flexibly coupling with the DNCORE, the DAN or the salience networks, thus reinforcing or reducing the automatic constraints being exerted by the DNCORE, the DAN or the salience networks.
Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering — how mental states change over time — have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.
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James, W. The Principles of Psychology (Henry Holt and Company, 1890).
Callard, F., Smallwood, J., Golchert, J. & Margulies, D. S. The era of the wandering mind? Twenty-first century research on self-generated mental activity. Front. Psychol. 4, 891 (2013).
Andreasen, N. C. et al. Remembering the past: two facets of episodic memory explored with positron emission tomography. Am. J. Psychiatry 152, 1576–1585 (1995).
Binder, J. R., Frost, J. A. & Hammeke, T. A. Conceptual processing during the conscious resting state: a functional MRI study. J. Cogn. Neurosci. 11, 80–93 (1999).
Stark, C. E. & Squire, L. R. When zero is not zero: the problem of ambiguous baseline conditions in fMRI. Proc. Natl Acad. Sci. USA 98, 12760–12766 (2001).
Christoff, K. & Gabrieli, J. D. E. The frontopolar cortex and human cognition: evidence for a rostrocaudal hierarchical organization within the human prefrontal cortex. Psychobiology 28, 168–186 (2000).
Shulman, G. L. et al. Common blood flow changes across visual tasks: II. Decreases cerebral cortex. J. Cogn. Neurosci. 9, 648–663 (1997). This meta-analysis provides convincing evidence that a set of specific brain regions, which later became known as the default mode network, becomes consistently activated during rest.
Raichle, M. E. et al. A default mode of brain function. Proc. Natl Acad. Sci. USA 98, 676–682 (2001). This highly influential theoretical paper coined the term 'default mode' to refer to cognitive and neural processes that occur in the absence of external task demands.
Singer, J. L. Daydreaming: An Introduction to the Experimental Study of Inner Experience (Random House, 1966).
Antrobus, J. S. Information theory and stimulus-independent thought. Br. J. Psychol. 59, 423–430 (1968).
Antrobus, J. S., Singer, J. L., Goldstein, S. & Fortgang, M. Mind wandering and cognitive structure. Trans. NY Acad. Sci. 32, 242–252 (1970).
Filler, M. S. & Giambra, L. M. Daydreaming as a function of cueing and task difficulty. Percept. Mot. Skills 37, 503–509 (1973).
Giambra, L. M. Adult male daydreaming across the life span: a replication, further analyses, and tentative norms based upon retrospective reports. Int. J. Aging Hum. Dev. 8, 197–228 (1977).
Giambra, L. M. Sex differences in daydreaming and related mental activity from the late teens to the early nineties. Int. J. Aging Hum. Dev. 10, 1–34 (1979).
Klinger, E. & Cox, W. M. Dimensions of thought flow in everyday life. Imagin. Cogn. Pers. 7, 105–128 (1987). This is probably the earliest experience sampling study of mind-wandering in daily life, revealing that adults spend approximately one-third of their waking life engaged in undirected thinking.
Giambra, L. M. Task-unrelated-thought frequency as a function of age: a laboratory study. Psychol. Aging 4, 136–143 (1989).
Teasdale, J. D., Proctor, L., Lloyd, C. A. & Baddeley, A. D. Working memory and stimulus-independent thought: effects of memory load and presentation rate. Eur. J. Cogn. Psychol. 5, 417–433 (1993).
Giambra, L. M. A laboratory method for investigating influences on switching attention to task-unrelated imagery and thought. Conscious. Cogn. 4, 1–21 (1995).
Klinger, E. Structure and Functions of Fantasy (John Wiley & Sons, 1971). This pioneering book summarizes the early empirical research on daydreaming and introduces important theoretical hypotheses, including the idea that task-unrelated thoughts are often about 'current concerns'.
Smallwood, J. & Schooler, J. W. The restless mind. Psychol. Bull. 132, 946–958 (2006). This paper put mind-wandering in the forefront of psychological research, advancing the influential hypothesis that executive resources support mind-wandering.
Killingsworth, M. A. & Gilbert, D. T. A wandering mind is an unhappy mind. Science 330, 932 (2010).
Mason, M. F. et al. Wandering minds: the default network and stimulus-independent thought. Science 315, 393–395 (2007). This influential paper brought mind-wandering to the forefront of neuroscientific research, arguing for a link between DN recruitment and stimulus-independent thought.
Christoff, K., Gordon, A. M., Smallwood, J., Smith, R. & Schooler, J. W. Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proc. Natl Acad. Sci. USA 106, 8719–8724 (2009). This paper is the first to use online experience sampling to examine the neural correlates of mind-wandering and the first to find joint activation of the DN and executive network during this phenomenon.
Callard, F., Smallwood, J. & Margulies, D. S. Default positions: how neuroscience's historical legacy has hampered investigation of the resting mind. Front. Psychol. 3, 321 (2012).
Smallwood, J. & Schooler, J. W. The science of mind wandering: empirically navigating the stream of consciousness. Annu. Rev. Psychol. 66, 487–518 (2015). This comprehensive review synthesizes the recent research characterizing mind-wandering as task-unrelated and/or stimulus-independent thought.
Christoff, K. Undirected thought: neural determinants and correlates. Brain Res. 1428, 51–59 (2012). This review disambiguates between different definitions of spontaneous thought and mind-wandering, and it argues that current definitions do not capture the dynamics of thought.
Irving, Z. C. Mind-wandering is unguided attention: accounting for the 'purposeful' wanderer. Philos. Stud. 173, 547–571 (2016). This is one of the first philosophical theories of mind-wandering; this paper defines mind-wandering as unguided attention to explain why its dynamics contrast with automatically and deliberately guided forms of attention such as rumination and goal-directed thinking.
Carruthers, P. The Centered Mind: What the Science of Working Memory Shows Us About the Nature of Human Thought (Oxford Univ. Press, 2015).
Simpson, J. A. The Oxford English Dictionary (Clarendon Press, 1989).
Kane, M. J. et al. For whom the mind wanders, and when: an experience-sampling study of working memory and executive control in daily life. Psychol. Sci. 18, 614–621 (2007). This study of mind-wandering in everyday life is one of the most important investigations into the complex relationship between mind-wandering and executive control.
Baird, B., Smallwood, J. & Schooler, J. W. Back to the future: autobiographical planning and the functionality of mind-wandering. Conscious. Cogn. 20, 1604–1611 (2011).
Morsella, E., Ben-Zeev, A., Lanska, M. & Bargh, J. A. The spontaneous thoughts of the night: how future tasks breed intrusive cognitions. Social Cogn. 28, 641–650 (2010).
Miller, E. K. & Cohen, J. D. An integrative theory of prefrontal cortex function. Annu. Rev. Neurosci. 24, 167–202 (2001).
Miller, E. K. The prefrontal cortex and cognitive control. Nat. Rev. Neurosci. 1, 59–65 (2000).
Markovic, J., Anderson, A. K. & Todd, R. M. Tuning to the significant: neural and genetic processes underlying affective enhancement of visual perception and memory. Behav. Brain Res. 259, 229–241 (2014).
Todd, R. M., Cunningham, W. A., Anderson, A. K. & Thompson, E. Affect-biased attention as emotion regulation. Trends Cogn. Sci. 16, 365–372 (2012).
Pessoa, L. The Cognitive-Emotional Brain: From Interactions to Integration (MIT Press, 2013).
Jonides, J. & Yantis, S. Uniqueness of abrupt visual onset in capturing attention. Percept. Psychophys. 43, 346–354 (1988).
Christoff, K., Gordon, A. M. & Smith, R. in Neuroscience of Decision Making (eds Vartanian, O. & Mandel, D. R.) 259–284 (Psychology Press, 2011).
Stawarczyk, D., Majerus, S., Maj, M., Van der Linden, M. & D'Argembeau, A. Mind-wandering: phenomenology and function as assessed with a novel experience sampling method. Acta Psychol. (Amst.) 136, 370–381 (2011).
Spreng, R. N., Mar, R. A. & Kim, A. S. N. The common neural basis of autobiographical memory, prospection, navigation, theory of mind, and the default mode: a quantitative meta-analysis. J. Cogn. Neurosci. 21, 489–510 (2009). This paper provides some of the first quantitative evidence that the DN is associated with multiple cognitive functions.
Andrews-Hanna, J. R. The brain's default network and its adaptive role in internal mentation. Neuroscientist 18, 251–270 (2012). This recent review describes a large-scale functional meta-analysis on the cognitive functions, functional subdivisions and clinical dysfunction of the DN.
Buckner, R. L. & Carroll, D. C. Self-projection and the brain. Trends Cogn. Sci. 11, 49–57 (2007).
Buckner, R. L., Andrews-Hanna, J. R. & Schacter, D. L. The brain's default network: anatomy, function, and relevance to disease. Ann. NY Acad. Sci. 1124, 1–38 (2008). This comprehensive review bridges across neuroscience, psychology and clinical research, and introduces a prominent hypothesis — the 'internal mentation hypothesis' — that the DN has an important role in spontaneous and directed forms of internal mentation.
Andrews-Hanna, J. R., Reidler, J. S., Sepulcre, J., Poulin, R. & Buckner, R. L. Functional-anatomic fractionation of the brain's default network. Neuron 65, 550–562 (2010).
Schacter, D. L., Addis, D. R. & Buckner, R. L. Remembering the past to imagine the future: the prospective brain. Nat. Rev. Neurosci. 8, 657–661 (2007).
Andrews-Hanna, J. R., Smallwood, J. & Spreng, R. N. The default network and self-generated thought: component processes, dynamic control, and clinical relevance. Ann. NY Acad. Sci. 1316, 29–52 (2014).
Corbetta, M., Patel, G. & Shulman, G. L. The reorienting system of the human brain: from environment to theory of mind. Neuron 58, 306–324 (2008). This paper outlines an influential theoretical framework that extends an earlier model by Corbetta and Shulman that drew a crucial distinction between the DAN and VAN.
Vanhaudenhuyse, A. et al. Two distinct neuronal networks mediate the awareness of environment and of self. J. Cogn. Neurosci. 23, 570–578 (2011).
Smallwood, J. Distinguishing how from why the mind wanders: a process–occurrence framework for self-generated mental activity. Psychol. Bull. 139, 519–535 (2013). This theoretical paper presents an important distinction between the events that determine when an experience initially occurs from the processes that sustain an experience over time.
Toro, R., Fox, P. T. & Paus, T. Functional coactivation map of the human brain. Cereb. Cortex 18, 2553–2559 (2008).
Fox, M. D. et al. The human brain is intrinsically organized into dynamic, anticorrelated functional networks. Proc. Natl Acad. Sci. USA 102, 9673–9678 (2005). This paper provides a unique insight into the functional antagonism between the default and dorsal attention systems.
Keller, C. J. et al. Neurophysiological investigation of spontaneous correlated and anticorrelated fluctuations of the BOLD signal. J. Neurosci. 33, 6333–6342 (2013).
Seeley, W. W. et al. Dissociable intrinsic connectivity networks for salience processing and executive control. J. Neurosci. 27, 2349–2356 (2007). This paper is the first to name the salience network and characterize its functional neuroanatomy.
Kucyi, A., Hodaie, M. & Davis, K. D. Lateralization in intrinsic functional connectivity of the temporoparietal junction with salience- and attention-related brain networks. J. Neurophysiol. 108, 3382–3392 (2012).
Power, J. D. et al. Functional network organization of the human brain. Neuron 72, 665–678 (2011).
Cole, M. W. et al. Multi-task connectivity reveals flexible hubs for adaptive task control. Nat. Neurosci. 16, 1348–1355 (2013).
Vincent, J. L., Kahn, I., Snyder, A. Z., Raichle, M. E. & Buckner, R. L. Evidence for a frontoparietal control system revealed by intrinsic functional connectivity. J. Neurophysiol. 100, 3328–3342 (2008).
Niendam, T. A. et al. Meta-analytic evidence for a superordinate cognitive control network subserving diverse executive functions. Cogn. Affect. Behav. Neurosci. 12, 241–268 (2012).
Spreng, R. N., Stevens, W. D., Chamberlain, J. P., Gilmore, A. W. & Schacter, D. L. Default network activity, coupled with the frontoparietal control network, supports goal-directed cognition. Neuroimage 53, 303–317 (2010). This paper demonstrates how the DN couples with the FPCN for personally salient, goal-directed information processing.
Dixon, M. L., Fox, K. C. R. & Christoff, K. A framework for understanding the relationship between externally and internally directed cognition. Neuropsychologia 62, 321–330 (2014).
Dosenbach, N. U. F. et al. A core system for the implementation of task sets. Neuron 50, 799–812 (2006).
Dosenbach, N. U. F. et al. Distinct brain networks for adaptive and stable task control in humans. Proc. Natl Acad. Sci. USA 104, 11073–11078 (2007).
Dosenbach, N. U. F., Fair, D. A., Cohen, A. L., Schlaggar, B. L. & Petersen, S. E. A dual-networks architecture of top-down control. Trends Cogn. Sci. 12, 99–105 (2008).
Yeo, B. T. T. et al. The organization of the human cerebral cortex estimated by intrinsic functional connectivity. J. Neurophysiol. 106, 1125–1165 (2011). This seminal paper uses resting-state functional connectivity and clustering approaches in 1,000 individuals to parcellate the brain into seven canonical large-scale networks.
Najafi, M., McMenamin, B. W., Simon, J. Z. & Pessoa, L. Overlapping communities reveal rich structure in large-scale brain networks during rest and task conditions. Neuroimage 135, 92–106 (2016).
McGuire, P. K., Paulesu, E., Frackowiak, R. S. & Frith, C. D. Brain activity during stimulus independent thought. Neuroreport 7, 2095–2099 (1996).
McKiernan, K. A., D'Angelo, B. R., Kaufman, J. N. & Binder, J. R. Interrupting the 'stream of consciousness': an fMRI investigation. Neuroimage 29, 1185–1191 (2006).
Gilbert, S. J., Dumontheil, I., Simons, J. S., Frith, C. D. & Burgess, P. W. Comment on 'wandering minds: the default network and stimulus-independent thought'. Science 317, 43b (2007).
Stawarczyk, D., Majerus, S., Maquet, P. & D'Argembeau, A. Neural correlates of ongoing conscious experience: both task-unrelatedness and stimulus-independence are related to default network activity. PLoS ONE 6, e16997 (2011).
Fox, K. C. R., Spreng, R. N., Ellamil, M., Andrews-Hanna, J. R. & Christoff, K. The wandering brain: meta-analysis of functional neuroimaging studies of mind-wandering and related spontaneous thought processes. Neuroimage 111, 611–621 (2015). This paper presents the first quantitative meta-analysis of neuroimaging studies on task-unrelated and/or stimulus-independent thought, revealing the involvement of the DN and other large-scale networks that were not traditionally thought to play a part in mind-wandering.
Ingvar, D. H. 'Hyperfrontal' distribution of the cerebral grey matter flow in resting wakefulness; on the functional anatomy of the conscious state. Acta Neurol. Scand. 60, 12–25 (1979). This paper by David Ingvar, a pioneer of human neuroimaging, provides the original observations that a resting brain is an active one and highlights the finding that prefrontal executive regions are active even at rest.
Christoff, K., Ream, J. M. & Gabrieli, J. D. E. Neural basis of spontaneous thought processes. Cortex 40, 623–630 (2004).
D'Argembeau, A. et al. Self-referential reflective activity and its relationship with rest: a PET study. Neuroimage 25, 616–624 (2005).
Spiers, H. J. & Maguire, E. A. Spontaneous mentalizing during an interactive real world task: an fMRI study. Neuropsychologia 44, 1674–1682 (2006).
Wang, K. et al. Offline memory reprocessing: involvement of the brain's default network in spontaneous thought processes. PLoS ONE 4, e4867 (2009).
Dumontheil, I., Gilbert, S. J., Frith, C. D. & Burgess, P. W. Recruitment of lateral rostral prefrontal cortex in spontaneous and task-related thoughts. Q. J. Exp. Psychol. 63, 1740–1756 (2010).
Posner, M. I. & Rothbart, M. K. Attention, self-regulation and consciousness. Phil. Trans. R. Soc. Lond. B 353, 1915–1927 (1998).
Duncan, J. & Owen, A. M. Common regions of the human frontal lobe recruited by diverse cognitive demands. Trends Neurosci. 23, 475–483 (2000).
Botvinick, M. M., Braver, T. S., Barch, D. M., Carter, C. S. & Cohen, J. D. Conflict monitoring and cognitive control. Psychol. Rev. 108, 624–652 (2001).
Banich, M. T. Executive function: the search for an integrated account. Curr. Direct. Psychol. Sci. 18, 89–94 (2009).
Prado, J., Chadha, A. & Booth, J. R. The brain network for deductive reasoning: a quantitative meta-analysis of 28 neuroimaging studies. J. Cogn. Neurosci. 23, 3483–3497 (2011).
McVay, J. C. & Kane, M. J. Does mind wandering reflect executive function or executive failure? Comment on Smallwood and Schooler (2006) and Watkins (2008). Psychol. Bull. 136, 188–197 (2010). This paper presents the theoretically influential control failure hypothesis, which is opposed to the thesis that executive function supports mind-wandering.
Kane, M. J. & McVay, J. C. What mind wandering reveals about executive-control abilities and failures. Curr. Direct. Psychol. Sci. 21, 348–354 (2012).
Levinson, D. B., Smallwood, J. & Davidson, R. J. The persistence of thought: evidence for a role of working memory in the maintenance of task-unrelated thinking. Psychol. Sci. 23, 375–380 (2012).
Salthouse, T. A., Fristoe, N., McGuthry, K. E. & Hambrick, D. Z. Relation of task switching to speed, age, and fluid intelligence. Psychol. Aging 13, 445–461 (1998).
Maillet, D. & Schacter, D. L. From mind wandering to involuntary retrieval: age-related differences in spontaneous cognitive processes. Neuropsychologia 80, 142–156 (2016).
Axelrod, V., Rees, G., Lavidor, M. & Bar, M. Increasing propensity to mind-wander with transcranial direct current stimulation. Proc. Natl Acad. Sci. USA 112, 3314–3319 (2015).
Schooler, J. W. et al. Meta-awareness, perceptual decoupling and the wandering mind. Trends Cogn. Sci. 15, 319–326 (2011).
Smallwood, J., Beach, E. & Schooler, J. W. Going AWOL in the brain: mind wandering reduces cortical analysis of external events. J. Cogn. Neurosci. 20, 458–469 (2008).
Kam, J. W. Y. et al. Slow fluctuations in attentional control of sensory cortex. J. Cogn. Neurosci. 23, 460–470 (2011).
Gelbard-Sagiv, H., Mukamel, R., Harel, M., Malach, R. & Fried, I. Internally generated reactivation of single neurons in human hippocampus during free recall. Science 322, 96–101 (2008). This pioneering study aimed to identify the neural origins of spontaneously recalled memories, finding strong evidence for the initial generation in the MTL.
Ellamil, M. et al. Dynamics of neural recruitment surrounding the spontaneous arising of thoughts in experienced mindfulness practitioners. Neuroimage 136, 186–196 (2016). This study is the first to reveal a sequential recruitment of the DN MTL , DN CORE , and FPCN immediately before, during and subsequent to the onset of spontaneous thoughts.
Andrews-Hanna, J. R., Reidler, J. S., Huang, C. & Buckner, R. L. Evidence for the default network's role in spontaneous cognition. J. Neurophysiol. 104, 322–335 (2010).
Kucyi, A. & Davis, K. D. Dynamic functional connectivity of the default mode network tracks daydreaming. Neuroimage 100, 471–480 (2014).
Foster, D. J. & Wilson, M. A. Reverse replay of behavioural sequences in hippocampal place cells during the awake state. Nature 440, 680–683 (2006).
Karlsson, M. P. & Frank, L. M. Awake replay of remote experiences in the hippocampus. Nat. Neurosci. 12, 913–918 (2009).
Carr, M. F., Jadhav, S. P. & Frank, L. M. Hippocampal replay in the awake state: a potential substrate for memory consolidation and retrieval. Nat. Neurosci. 14, 147–153 (2011).
Dragoi, G. & Tonegawa, S. Distinct preplay of multiple novel spatial experiences in the rat. Proc. Natl Acad. Sci. USA 110, 9100–9105 (2013).
Dragoi, G. & Tonegawa, S. Preplay of future place cell sequences by hippocampal cellular assemblies. Nature 469, 397–401 (2011).
Ólafsdóttir, H. F., Barry, C., Saleem, A. B. & Hassabis, D. Hippocampal place cells construct reward related sequences through unexplored space. eLife 4, e06063 (2015).
Stark, C. E. L. & Clark, R. E. The medial temporal lobe. Annu. Rev. Neurosci. 27, 279–306 (2004).
Moscovitch, M., Cabeza, R., Winocur, G. & Nadel, L. Episodic memory and beyond: the hippocampus and neocortex in transformation. Annu. Rev. Psychol. 67, 105–134 (2016).
Romero, K. & Moscovitch, M. Episodic memory and event construction in aging and amnesia. J. Mem. Lang. 67, 270–284 (2012).
Hassabis, D., Kumaran, D. & Maguire, E. A. Using imagination to understand the neural basis of episodic memory. J. Neurosci. 27, 14365–14374 (2007).
Buckner, R. L. The role of the hippocampus in prediction and imagination. Annu. Rev. Psychol. 61, 27–48 (2010).
Hassabis, D. & Maguire, E. A. The construction system of the brain. Phil. Trans. R. Soc. B 364, 1263–1271 (2009).
Schacter, D. L. et al. The future of memory: remembering, imagining, and the brain. Neuron 76, 677–694 (2012).
Schacter, D. L., Addis, D. R. & Buckner, R. L. Episodic simulation of future events: concepts, data, and applications. Ann. NY Acad. Sci. 1124, 39–60 (2008).
Moscovitch, M. Memory and working-with-memory: a component process model based on modules and central systems. J. Cogn. Neurosci. 4, 257–267 (1992). This paper introduces the influential component process model of memory.
Teyler, T. J. & DiScenna, P. The hippocampal memory indexing theory. Behav. Neurosci. 100, 147–154 (1986).
Moscovitch, M. The hippocampus as a “stupid,” domain-specific module: implications for theories of recent and remote memory, and of imagination. Can. J. Exp. Psychol. 62, 62–79 (2008).
Bar, M., Aminoff, E., Mason, M. & Fenske, M. The units of thought. Hippocampus 17, 420–428 (2007). This paper introduces a novel hypothesis on the associative processes underlying a train of thoughts, originating in the MTL.
Aminoff, E. M., Kveraga, K. & Bar, M. The role of the parahippocampal cortex in cognition. Trends Cogn. Sci. 17, 379–390 (2013).
Christoff, K., Keramatian, K., Gordon, A. M., Smith, R. & Mädler, B. Prefrontal organization of cognitive control according to levels of abstraction. Brain Res. 1286, 94–105 (2009).
Dixon, M. L., Fox, K. C. R. & Christoff, K. Evidence for rostro-caudal functional organization in multiple brain areas related to goal-directed behavior. Brain Res. 1572, 26–39 (2014).
McCaig, R. G., Dixon, M., Keramatian, K., Liu, I. & Christoff, K. Improved modulation of rostrolateral prefrontal cortex using real-time fMRI training and meta-cognitive awareness. Neuroimage 55, 1298–1305 (2011).
Dixon, M. L. & Christoff, K. The decision to engage cognitive control is driven by expected reward-value: neural and behavioral evidence. PLoS ONE 7, e51637 (2012).
Yin, H. H. & Knowlton, B. J. The role of the basal ganglia in habit formation. Nat. Rev. Neurosci. 7, 464–476 (2006).
Burguière. E., Monteiro, P., Mallet, L., Feng, G. & Graybiel, A. M. Striatal circuits, habits, and implications for obsessive–compulsive disorder. Curr. Opin. Neurobiol. 30, 59–65 (2015).
Mathews, A. & MacLeod, C. Cognitive vulnerability to emotional disorders. Annu. Rev. Clin. Psychol. 1, 167–195 (2005).
Gotlib, I. H. & Joormann, J. Cognition and depression: current status and future directions. Annu. Rev. Clin. Psychol. 6, 285–312 (2010).
Nolen-Hoeksema, S., Wisco, B. E. & Lyubomirsky, S. Rethinking rumination. Perspect. Psychol. Sci. 3, 400–424 (2008).
Watkins, E. R. Constructive and unconstructive repetitive thought. Psychol. Bull. 134, 163–206 (2008). This comprehensive review and theory article links the psychological literature on task-unrelated or stimulus-independent thought to the clinical literature on rumination and other forms of repetitive thought, proposing multiple factors that govern whether repetitive thought is constructive or unconstructive.
Giambra, L. M. & Traynor, T. D. Depression and daydreaming; an analysis based on self-ratings. J. Clin. Psychol. 34, 14–25 (1978).
Larsen, R. J. & Cowan, G. S. Internal focus of attention and depression: a study of daily experience. Motiv. Emot. 12, 237–249 (1988).
Whitfield-Gabrieli, S. & Ford, J. M. Default mode network activity and connectivity in psychopathology. Annu. Rev. Clin. Psychol. 8, 49–76 (2012).
Anticevic, A. et al. The role of default network deactivation in cognition and disease. Trends Cogn. Sci. 16, 584–592 (2012).
Hamilton, J. P. et al. Functional neuroimaging of major depressive disorder: a meta-analysis and new integration of baseline activation and neural response data. Am. J. Psychiatry 169, 693–703 (2012).
Kaiser, R. H. et al. Distracted and down: neural mechanisms of affective interference in subclinical depression. Soc. Cogn. Affect. Neurosci. 10, 654–663 (2015).
Kaiser, R. H., Andrews-Hanna, J. R., Wager, T. D. & Pizzagalli, D. A. Large-scale network dysfunction in major depressive disorder. JAMA Psychiatry 72, 603–637 (2015). This meta-analysis of resting-state functional connectivity studies in major depressive disorder provides quantitative support for functional-network imbalances, which reflect heightened internally focused thought in this disorder.
Kaiser, R. H. et al. Dynamic resting-state functional connectivity in major depression. Neuropsychopharmacology 41, 1822–1830 (2015).
Spinhoven, P., Drost, J., van Hemert, B. & Penninx, B. W. Common rather than unique aspects of repetitive negative thinking are related to depressive and anxiety disorders and symptoms. J. Anxiety Disord. 33, 45–52 (2015).
Borkovec, T. D., Ray, W. J. & Stober, J. Worry: a cognitive phenomenon intimately linked to affective, physiological, and interpersonal behavioral processes. Cognit. Ther. Res. 22, 561–576 (1998).
Oathes, D. J., Patenaude, B., Schatzberg, A. F. & Etkin, A. Neurobiological signatures of anxiety and depression in resting-state functional magnetic resonance imaging. Biol. Psychiatry 77, 385–393 (2015).
Bar-Haim, Y., Lamy, D., Pergamin, L., Bakermans-Kranenburg, M. J. & van IJzendoorn, M. H. Threat-related attentional bias in anxious and nonanxious individuals: a meta-analytic study. Psychol. Bull. 133, 1–24 (2007).
Williams, J., Watts, F. N., MacLeod, C. & Mathews, A. Cognitive Psychology and Emotional Disorders (John Wiley & Sons, 1997).
Etkin, A., Prater, K. E., Schatzberg, A. F., Menon, V. & Greicius, M. D. Disrupted amygdalar subregion functional connectivity and evidence of a compensatory network in generalized anxiety disorder. Arch. Gen. Psychiatry 66, 1361–1372 (2009).
Ipser, J. C., Singh, L. & Stein, D. J. Meta-analysis of functional brain imaging in specific phobia. Psychiatry Clin. Neurosci. 67, 311–322 (2013).
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 2013).
Boonstra, A. M., Oosterlaan, J., Sergeant, J. A. & Buitelaar, J. K. Executive functioning in adult ADHD: a meta-analytic review. Psychol. Med. 35, 1097–1108 (2005).
Willcutt, E. G., Doyle, A. E., Nigg, J. T., Faraone, S. V. & Pennington, B. F. Validity of the executive function theory of attention-deficit/hyperactivity disorder: a meta-analytic review. Biol. Psychiatry 57, 1336–1346 (2005).
Kofler, M. J. et al. Reaction time variability in ADHD: a meta-analytic review of 319 studies. Clin. Psychol. Rev. 33, 795–811 (2013).
Shaw, G. A. & Giambra, L. Task unrelated thoughts of college students diagnosed as hyperactive in childhood. Dev. Neuropsychol. 9, 17–30 (1993).
Franklin, M. S. et al. Tracking distraction: the relationship between mind-wandering, meta-awareness, and ADHD symptomatology. J. Atten. Disord. http://dx.doi.org/10.1177/1087054714543494 (2014).
De La Fuente, A., Xia, S., Branch, C. & Li, X. A review of attention-deficit/hyperactivity disorder from the perspective of brain networks. Front. Hum. Neurosci. 7, 192 (2013).
Castellanos, F. X. & Proal, E. Large-scale brain systems in ADHD: beyond the prefrontal–striatal model. Trends Cogn. Sci. 16, 17–26 (2012).
Hart, H., Radua, J., Mataix-Cols, D. & Rubia, K. Meta-analysis of fMRI studies of timing in attention-deficit hyperactivity disorder (ADHD). Neurosci. Biobehav. Rev. 36, 2248–2256 (2012).
Hart, H., Radua, J., Nakao, T., Mataix-Cols, D. & Rubia, K. Meta-analysis of functional magnetic resonance imaging studies of inhibition and attention in attention-deficit/hyperactivity disorder. JAMA Psychiatry 70, 185–198 (2013).
Fassbender, C. et al. A lack of default network suppression is linked to increased distractibility in ADHD. Brain Res. 1273, 114–128 (2009).
Cortese, S. et al. Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies. Am. J. Psychiatry 169, 1038–1055 (2012).
Castellanos, F. X. et al. Cingulate-precuneus interactions: a new locus of dysfunction in adult attention-deficit/hyperactivity disorder. Biol. Psychiatry 63, 332–337 (2008).
Uddin, L. Q. et al. Network homogeneity reveals decreased integrity of default-mode network in ADHD. J. Neurosci. Methods 169, 249–254 (2008).
Tomasi, D. & Volkow, N. D. Abnormal functional connectivity in children with attention-deficit/hyperactivity disorder. Biol. Psychiatry 71, 443–450 (2012).
Mattfeld, A. T. et al. Brain differences between persistent and remitted attention deficit hyperactivity disorder. Brain 137, 2423–2428 (2014).
Sun, L. et al. Abnormal functional connectivity between the anterior cingulate and the default mode network in drug-naïve boys with attention deficit hyperactivity disorder. Psychiatry Res. 201, 120–127 (2012).
McCarthy, H. et al. Attention network hypoconnectivity with default and affective network hyperconnectivity in adults diagnosed with attention-deficit/hyperactivity disorder in childhood. JAMA Psychiatry 70, 1329–1337 (2013).
Fair, D. A. et al. The maturing architecture of the brain's default network. Proc. Natl Acad. Sci. USA 105, 4028–4032 (2008).
Sripada, C. et al. Disrupted network architecture of the resting brain in attention-deficit/hyperactivity disorder. Hum. Brain Mapp. 35, 4693–4705 (2014). By analysing data from more than 750 participants, this paper links childhood ADHD to abnormal resting-state functional connectivity involving the DN.
Fair, D. A. et al. Atypical default network connectivity in youth with attention-deficit/hyperactivity disorder. Biol. Psychiatry 68, 1084–1091 (2010).
Anderson, A. et al. Non-negative matrix factorization of multimodal MRI, fMRI and phenotypic data reveals differential changes in default mode subnetworks in ADHD. Neuroimage 102, 207–219 (2014).
Power, J. D., Barnes, K. A., Snyder, A. Z., Schlaggar, B. L. & Petersen, S. E. Spurious but systematic correlations in functional connectivity MRI networks arise from subject motion. Neuroimage 59, 2142–2154 (2012).
Van Dijk, K. R. A., Sabuncu, M. R. & Buckner, R. L. The influence of head motion on intrinsic functional connectivity MRI. Neuroimage 59, 431–438 (2012).
Sonuga-Barke, E. J. S. & Castellanos, F. X. Spontaneous attentional fluctuations in impaired states and pathological conditions: a neurobiological hypothesis. Neurosci. Biobehav. Rev. 31, 977–986 (2007).
Kerns, J. G. & Berenbaum, H. Cognitive impairments associated with formal thought disorder in people with schizophrenia. J. Abnorm. Psychol. 111, 211–224 (2002).
Videbeck, S. L. Psychiatric Mental Health Nursing (Lippincott Williams & Wilkins, 2006).
Hales, R. E., Yudofsky, S. C. & Roberts, L. W. The American Psychiatric Publishing Textbook of Psychiatry 6th edn (American Psychiatric Publishing, 2014).
Haijma, S. V. et al. Brain volumes in schizophrenia: a meta-analysis in over 18 000 subjects. Schizophr. Bull. 39, 1129–1138 (2013).
Glahn, D. C. et al. Meta-analysis of gray matter anomalies in schizophrenia: application of anatomic likelihood estimation and network analysis. Biol. Psychiatry 64, 774–781 (2008).
Fornito, A., Yücel, M., Patti, J., Wood, S. J. & Pantelis, C. Mapping grey matter reductions in schizophrenia: an anatomical likelihood estimation analysis of voxel-based morphometry studies. Schizophr. Res. 108, 104–113 (2009).
Ellison-Wright, I. & Bullmore, E. Anatomy of bipolar disorder and schizophrenia: a meta-analysis. Schizophr. Res. 117, 1–12 (2010).
Vita, A., De Peri, L., Deste, G., Barlati, S. & Sacchetti, E. The effect of antipsychotic treatment on cortical gray matter changes in schizophrenia: does the class matter? A meta-analysis and meta-regression of longitudinal magnetic resonance imaging studies. Biol. Psychiatry 78, 403–412 (2015).
Cole, M. W., Anticevic, A., Repovs, G. & Barch, D. Variable global dysconnectivity and individual differences in schizophrenia. Biol. Psychiatry 70, 43–50 (2011).
Argyelan, M. et al. Resting-state fMRI connectivity impairment in schizophrenia and bipolar disorder. Schizophr. Bull. 40, 100–110 (2014).
Cole, M. W., Yarkoni, T., Repovs, G., Anticevic, A. & Braver, T. S. Global connectivity of prefrontal cortex predicts cognitive control and intelligence. J. Neurosci. 32, 8988–8999 (2012).
Baker, J. T. et al. Disruption of cortical association networks in schizophrenia and psychotic bipolar disorder. JAMA Psychiatry 71, 109–110 (2014).
Karbasforoushan, H. & Woodward, N. D. Resting-state networks in schizophrenia. Curr. Top. Med. Chem. 12, 2404–2414 (2013).
Jafri, M. J., Pearlson, G. D., Stevens, M. & Calhoun, V. D. A method for functional network connectivity among spatially independent resting-state components in schizophrenia. Neuroimage 39, 1666–1681 (2008).
Whitfield-Gabrieli, S. et al. Hyperactivity and hyperconnectivity of the default network in schizophrenia and in first-degree relatives of persons with schizophrenia. Proc. Natl Acad. Sci. USA 106, 1279–1284 (2009).
Palaniyappan, L., Simmonite, M., White, T. P., Liddle, E. B. & Liddle, P. F. Neural primacy of the salience processing system in schizophrenia. Neuron 79, 814–828 (2013).
Mittner, M., Hawkins, G. E., Boekel, W. & Forstmann, B. U. A neural model of mind wandering. Trends Cogn. Sci. 20, 570–578 (2016). This paper convincingly argues for the introduction of two important novel elements to the scientific study of mind-wandering: employing cognitive modelling and a consideration of neuromodulatory influences on thought.
Fox, K. C. R. & Christoff, K. in The Cognitive Neuroscience of Metacognition (eds Fleming, S. M. & Frith, C. D.) 293–319 (Springer, 2014).
Foulkes, D. & Fleisher, S. Mental activity in relaxed wakefulness. J. Abnorm. Psychol. 84, 66–75 (1975).
Fox, K. C. R., Nijeboer, S., Solomonova, E., Domhoff, G. W. & Christoff, K. Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports. Front. Hum. Neurosci. 7, 412 (2013).
De Bono, E. Six Thinking Hats (Little Brown and Company, 1985).
Ellamil, M., Dobson, C., Beeman, M. & Christoff, K. Evaluative and generative modes of thought during the creative process. Neuroimage 59, 1783–1794 (2012).
Beaty, R. E., Benedek, M., Kaufman, S. B. & Silvia, P. J. Default and executive network coupling supports creative idea production. Sci. Rep. 5, 10964 (2015).
Fox, K. C. R., Kang, Y., Lifshitz, M. & Christoff, K. in Hypnosis and Meditation (eds Raz, A. & Lifshitz, M.) 191–210 (Oxford Univ. Press, 2016).
Fazelpour, S. & Thompson, E. The Kantian brain: brain dynamics from a neurophenomenological perspective. Curr. Opin. Neurobiol. 31, 223–229 (2015).
The authors are grateful to R. Buckner, P. Carruthers, M. Cuddy-Keane, M. Dixon, S. Fazelpour, D. Stan, E. Thompson, R. Todd and the anonymous reviewers for their thoughtful feedback on earlier versions of this paper, and to A. Herrera-Bennett for help with the figure preparation. K.C. was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) (RGPIN 327317–11) and the Canadian Institutes of Health Research (CIHR) (MOP-115197). Z.C.I. was supported by a Social Sciences and Humanities Research Council of Canada (SSHRC) postdoctoral fellowship, the Balzan Styles of Reasoning Project and a Templeton Integrated Philosophy and Self Control grant. K.C.R.F. was supported by a Vanier Canada Graduate Scholarship. R.N.S. was supported by an Alzheimer's Association grant (NIRG-14-320049). J.R.A.-H. was supported by a Templeton Science of Prospection grant.
The authors declare no competing financial interests.
A mental state, or a sequence of mental states, including the transitions that lead to each state.
- Mental state
A transient cognitive or emotional state of the organism that can be described in terms of its contents (what the state is 'about') and the relation that the subject bears to the contents (for example, perceiving, believing, fearing, imagining or remembering).
- Task-unrelated thoughts
Thoughts with contents that are unrelated to what the person having those thoughts is currently doing.
Thinking that is characteristically fanciful (that is, divorced from physical or social reality); it can either be spontaneous, as in fanciful mind-wandering, or constrained, as during deliberately fantasizing about a topic.
- Stimulus-independent thought
A thought with contents that are unrelated to the current external perceptual environment.
- Cognitive control
A deliberate guidance of current thoughts, perceptions or actions, which is imposed in a goal-directed manner by currently active top-down executive processes.
- Affective salience
The emotional significance of percepts, thoughts or other elements of mental experience, which can draw and sustain attention through mechanisms outside of cognitive control.
- Sensory salience
Features of current perceptual experience, such as high perceptual contrast, which can draw and sustain attention through mechanisms outside of cognitive control.
The process of spontaneously or deliberately inferring one's own or other agents' mental states.
- Constructive mental simulations
Flexible combinations of distinct elements of prior experiences, constructed in the process of imagining a novel (often future-oriented) event.
- Lucid dreaming
A type of dreaming during which the dreamer is aware that he or she is currently dreaming and, in some cases, can have deliberate control over dream content and progression.
The ability to produce ideas that are both novel (that is, original and unique) and useful (that is, appropriate and meaningful).
- Experience sampling
A method in which participants are probed at random intervals and asked to report on aspects of their subjective experience immediately before the probe.
- Content-based dimensions of thought
Different ways of categorizing a thought based on its contents, including stimulus dependence (whether the thought is about stimuli that one is currently perceiving), task relatedness (whether the thought is about the current task), modality (visual, auditory, and so on), valence (whether the thought is negative, neutral or positive) or temporal orientation (whether the thought is about the past, present or future).
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Christoff, K., Irving, Z., Fox, K. et al. Mind-wandering as spontaneous thought: a dynamic framework. Nat Rev Neurosci 17, 718–731 (2016). https://doi.org/10.1038/nrn.2016.113
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