The human prefrontal cortex is a structurally and functionally heterogenous brain region, including multiple subregions that have been linked to different large-scale brain networks. It contributes ...to a broad range of mental phenomena, from goal-directed thought and executive functions to mind-wandering and psychedelic experience. Here we review what is known about the functions of different prefrontal subregions and their affiliations with large-scale brain networks to examine how they may differentially contribute to the diversity of mental phenomena associated with prefrontal function. An important dimension that distinguishes across different kinds of conscious experience is the stability or variability of mental states across time. This dimension is a central feature of two recently introduced theoretical frameworks-the dynamic framework of thought (DFT) and the relaxed beliefs under psychedelics (REBUS) model-that treat neurocognitive dynamics as central to understanding and distinguishing between different mental phenomena. Here, we bring these two frameworks together to provide a synthesis of how prefrontal subregions may differentially contribute to the stability and variability of thought and conscious experience. We close by considering future directions for this work.
The prefrontal cortex (PFC) plays a critical role in the generation and regulation of emotion. However, we lack an integrative framework for understanding how different emotion-related functions are ...organized across the entire expanse of the PFC, as prior reviews have generally focused on specific emotional processes (e.g., decision making) or specific anatomical regions (e.g., orbitofrontal cortex). Additionally, psychological theories and neuroscientific investigations have proceeded largely independently because of the lack of a common framework. Here, we provide a comprehensive review of functional neuroimaging, electrophysiological, lesion, and structural connectivity studies on the emotion-related functions of 8 subregions spanning the entire PFC. We introduce the appraisal-by-content model, which provides a new framework for integrating the diverse range of empirical findings. Within this framework, appraisal serves as a unifying principle for understanding the PFC's role in emotion, while relative content-specialization serves as a differentiating principle for understanding the role of each subregion. A synthesis of data from affective, social, and cognitive neuroscience studies suggests that different PFC subregions are preferentially involved in assigning value to specific types of inputs: exteroceptive sensations, episodic memories and imagined future events, viscero-sensory signals, viscero-motor signals, actions, others' mental states (e.g., intentions), self-related information, and ongoing emotions. We discuss the implications of this integrative framework for understanding emotion regulation, value-based decision making, emotional salience, and refining theoretical models of emotion. This framework provides a unified understanding of how emotional processes are organized across PFC subregions and generates new hypotheses about the mechanisms underlying adaptive and maladaptive emotional functioning.
Despite the ubiquitous nature of boredom, the definition, function, and correlates of boredom are still poorly understood. In this review, we summarize the “known” (consistent evidence) and “unknown” ...(inconsistent evidence) correlates of boredom. We show that boredom is consistently related to negative affect, task-unrelated thought, over-estimation of elapsed time, reduced agency, as well as to over- and under-stimulation. Activation of the default mode network was consistent across the few available fMRI studies, while the recruitment of other brain areas such as the hippocampus and anterior insular cortex, was a notable but less consistent correlate of boredom. Other less consistent correlates of boredom are also reviewed, such as the level of arousal and the mental attributions given to fluctuations of attention. Finally, we identify two critical factors that may contribute to current inconsistencies in the literature and may hamper further progress in the field. First, there is relatively little consistency in the way in which boredom has been operationalized across studies to date, with operationalizations of boredom ranging from negative affect paired with under-stimulation, over-stimulation, to negative affect paired with a lack of goal-directed actions. Second, preliminary evidence suggests the existence of distinct types of boredom (e.g., searching vs. apathetic) that may have different and sometimes even opposing correlates. Adopting a more precise and consistent way of operationalizing boredom, and arriving at an empirically validated taxonomy of different types of boredom, could serve to overcome the current roadblocks to facilitate further progress in our scientific understanding of boredom.
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.
Tremendous progress has been made in discerning the neurocognitive basis of value-based decision making and learning. Although the majority of studies to date have employed simple task paradigms, ...recent work has started to examine more complex aspects of value processing including: the value of engaging rule-based cognitive control; the integration of multiple pieces of information (e.g., reward magnitude and delay) to discern the best course of action; pursuing future rewards; valuation of abstract concepts (e.g., fairness); and comparing the value of executed versus imagined alternative actions. We provide a comprehensive review of functional neuroimaging, electrophysiological, and lesion evidence suggesting that the lateral prefrontal cortex (LPFC) plays a critical role in these complex aspects of value processing. In particular, we focus on the specific information that the LPFC represents, and argue that it includes both cognitive and value-based information. We also discuss how the role of the LPFC is distinct from other value-related regions. Finally, we articulate a framework for understanding the contribution of subregions along the rostro-caudal axis of the LPFC, and thereby bridge the cognitive control and decision making literatures.
The frontoparietal control network (FPCN) plays a central role in executive control. It has been predominantly viewed as a unitary domain general system. Here, we examined patterns of FPCN functional ...connectivity (FC) across multiple conditions of varying cognitive demands, to test for FPCN heterogeneity. We identified two distinct subsystems within the FPCN based on hierarchical clustering and machine learning classification analyses of within-FPCN FC patterns. These two FPCN subsystems exhibited distinct patterns of FC with the default network (DN) and the dorsal attention network (DAN). FPCNA exhibited stronger connectivity with the DN than the DAN, whereas FPCNB exhibited the opposite pattern. This twofold FPCN differentiation was observed across four independent datasets, across nine different conditions (rest and eight tasks), at the level of individual-participant data, as well as in meta-analytic coactivation patterns. Notably, the extent of FPCN differentiation varied across conditions, suggesting flexible adaptation to task demands. Finally, we used meta-analytic tools to identify several functional domains associated with the DN and DAN that differentially predict activation in the FPCN subsystems. These findings reveal a flexible and heterogeneous FPCN organization that may in part emerge from separable DN and DAN processing streams. We propose that FPCNA may be preferentially involved in the regulation of introspective processes, whereas FPCNB may be preferentially involved in the regulation of visuospatial perceptual attention.
Contemporary investigations regard creativity as a dynamic form of cognition that involves movement between the dissociable stages of creative generation and creative evaluation. Our recently ...proposed Dynamic Framework of Thought (Christoff et al., 2016) offered a conceptualization of these stages in terms of an interplay between sources of constraint and variability on thought. This initial conceptualization, however, has yet to be fully explicated and given targeted discussion. Here, we refine this framework’s account of creativity by highlighting the dynamic nature of creative thought, both within and between the stages of creative generation and evaluation. In particular, we emphasize that creative generation in particular is best regarded as a product of multiple, varying mental states, rather than being a singular mental state in and of itself. We also propose that the psychedelic state is a mental state with high potential for facilitating creative generation and update the Dynamic Framework of Thought to incorporate this state. This paper seeks to highlight the dynamic nature of the neurocognitive processes underlying creative thinking and to draw attention to the potential utility of psychedelic substances as experimental tools in the neuroscience of creativity.
•Creativity involves the dynamic traversal of varying neurocognitive states•Creative generation can occur in a number of distinct states•The psychedelic state may facilitate creative generation•Psychedelics may be a useful tool in the neuroscience of creativity
The neural basis and cognitive functions of various spontaneous thought processes, particularly mind-wandering, are increasingly being investigated. Although strong links have been drawn between the ...occurrence of spontaneous thought processes and activation in brain regions comprising the default mode network (DMN), spontaneous thought also appears to recruit other, non-DMN regions just as consistently. Here we present the first quantitative meta-analysis of neuroimaging studies of spontaneous thought and mind-wandering in order to address the question of their neural correlates. Examining 24 functional neuroimaging studies of spontaneous thought processes, we conducted a meta-analysis using activation likelihood estimation (ALE). A number of key DMN areas showed consistent recruitment across studies, including medial prefrontal cortex, posterior cingulate cortex, medial temporal lobe, and bilateral inferior parietal lobule. Numerous non-DMN regions, however, were also consistently recruited, including rostrolateral prefrontal cortex, dorsal anterior cingulate cortex, insula, temporopolar cortex, secondary somatosensory cortex, and lingual gyrus. These meta-analytic results indicate that DMN activation alone is insufficient to adequately capture the neural basis of spontaneous thought; frontoparietal control network areas, and other non-DMN regions, appear to be equally central. We conclude that further progress in the cognitive and clinical neuroscience of spontaneous thought will therefore require a re-balancing of our view of the contributions of various regions and networks throughout the brain, and beyond the DMN.
•Spontaneous thought (e.g., mind-wandering) is closely linked to the default network.•Spontaneous thought also appears to recruit other, non-default network regions.•We review and meta-analyze all neuroimaging studies of spontaneous thought (n=24).•We find consistent activations in both default and executive network regions.•Future studies should not restrict analyses to default network regions-of-interest.
Meditation is a family of mental practices that encompasses a wide array of techniques employing distinctive mental strategies. We systematically reviewed 78 functional neuroimaging (fMRI and PET) ...studies of meditation, and used activation likelihood estimation to meta-analyze 257 peak foci from 31 experiments involving 527 participants. We found reliably dissociable patterns of brain activation and deactivation for four common styles of meditation (focused attention, mantra recitation, open monitoring, and compassion/loving-kindness), and suggestive differences for three others (visualization, sense-withdrawal, and non-dual awareness practices). Overall, dissociable activation patterns are congruent with the psychological and behavioral aims of each practice. Some brain areas are recruited consistently across multiple techniques-including insula, pre/supplementary motor cortices, dorsal anterior cingulate cortex, and frontopolar cortex-but convergence is the exception rather than the rule. A preliminary effect-size meta-analysis found medium effects for both activations (d=0.59) and deactivations (d=-0.74), suggesting potential practical significance. Our meta-analysis supports the neurophysiological dissociability of meditation practices, but also raises many methodological concerns and suggests avenues for future research.
Cognitive neuroscience investigations of self-experience have mainly focused on the mental attribution of features to the self (self-related processing). In this paper, we highlight another ...fundamental, yet neglected, aspect of self-experience, that of being an agent. We propose that this aspect of self-experience depends on self-specifying processes, ones that implicitly specify the self by implementing a functional self/non-self distinction in perception, action, cognition and emotion. We describe two paradigmatic cases – sensorimotor integration and homeostatic regulation – and use the principles from these cases to show how cognitive control, including emotion regulation, is also self-specifying. We argue that externally directed, attention-demanding tasks, rather than suppressing self-experience, give rise to the self-experience of being a cognitive–affective agent. We conclude with directions for experimental work based on our framework.
PDF
