Though only a decade has elapsed since the default network was

Though only a decade has elapsed since the default network was first emphasized as being a large-scale brain system recent years have brought great insight into the network’s adaptive functions. that self-generated thought is a multi-faceted construct whose component processes are supported by different subsystems within the network. Second we focus on the dynamic nature of the default network emphasizing its connection with executive control systems when regulating aspects of internal thought. We conclude by discussing medical implications of disruptions to the integrity of the network and consider disorders when thought content becomes polarized or network relationships become disrupted or imbalanced. (Package 1) are a complex and heterogeneous class of cognition. Sometimes they are created with effort and purpose and can be directly related to personal goals and aspirations; other occasions they unfold without our intention hijacking attention Rabbit polyclonal to FBXW8. until a salient stimulus or intermittent instant of awareness alerts us to the present instant.1 2 Self-generated thoughts can also be a source of creative insight facilitating novel solutions to ongoing problems.3 At the same time such thoughts can lead to distress and unhappiness 4 disrupting task performance and preventing us from dealing with immediate issues.5 Understanding the psychological and neural mechanisms underlying self-generated thoughts including their adaptive and maladaptive functional outcomes has been a key aim of cognitive and Trimebutine neuroscientific research in recent years. Box 1 Self-generated thought and related terms Thoughts and feeling can arise that are only loosely related to ongoing sensory input. In the literature these experiences have been described using a wide range of terms. Some capture their independence from ongoing events such as or Others capture their internal rather than external focus: or One Trimebutine term that captures both their active nature and their relative independence from ongoing sensory input is in 2008 7 several questions remained unanswered. What do people think about when left to their own musings? Are different aspects of self-generated thought supported by unique components within the DN? How does the DN interact with other large-scale brain systems when maintaining an internal train of thought? Though recent years have contributed substantial progress towards answering these questions much still remains to be comprehended. Here we synthesize this research drawing parallels with a growing psychological literature on mind-wandering and highlighting several avenues for future research. Box 2 Defining the default network Although the regions that compose the DN were originally defined by patterns Trimebutine of deactivation during goal-directed tasks compared to passive control conditions this pattern breaks down when goal-directed tasks are of an internal nature (observe main text). Because of this task-related variability we Trimebutine instead define the DN based on its patterns of temporal correlations using resting-state functional connectivity MRI (RSFC).14 51 242 In a comprehensive set of studies Yeo Choi Buckner and colleagues applied clustering techniques to RSFC data collected from 1 0 participants to partition the cortex striatum and cerebellum into Trimebutine seven intrinsic large-scale brain systems.51 52 53 As shown in Determine 1a the DN includes voxels spanning the mPFC (the dmPFC the rostral anterior cingulate and parts of the anterior and ventral mPFC) lateral frontal cortex (the superior frontal cortex and the inferior frontal gyrus) medial parietal cortex (the posterior cingulate and retrosplenial cortex) medial temporal lobe (the hippocampus and parahippocampal cortices) lateral parietal cortex (spanning the angular gyrus and the posterior supramarginal gyrus/TPJ) and lateral temporal cortex (extending anteriorly to the temporal poles). In addition to these cortical regions the DN also includes large areas of the cerebellum (including Crus I and Crus II subdivisions) and the striatum (the medial wall of the caudate and the posterior putamen). Interestingly there exists substantial convergence between the spatial extent of the DN as defined with RSFC and with large-scale meta-analyses of functional neuroimaging data using NeuroSynth65 (Fig. 1b). Physique 1 The default network. (A) The default network as revealed by resting-state functional connectivity MRI of the cortex striatum and cerebellum. Physique created using data from Yeo comprised the hippocampus the.