TY - JOUR T1 - Isolated from input: Transmodal cortex in the default mode network supports perceptually-decoupled and conceptually-guided cognition JF - bioRxiv DO - 10.1101/150466 SP - 150466 AU - Charlotte Murphy AU - Elizabeth Jefferies AU - Shirley-Ann Rueschemeyer AU - Mladen Sormaz AU - Hao-ting Wang AU - Daniel S. Margulies AU - Jonathan Smallwood Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/06/15/150466.abstract N2 - The default mode network supports a variety of mental operations such as semantic processing, episodic memory retrieval, mental time travel and mind-wandering, yet the commonalities between these functions remains unclear. One possibility is that the default mode network supports cognition that is independent of the immediate environment; alternatively or additionally, it might support higher-order conceptual representations that draw together multiple features. We tested these accounts using a novel paradigm that contrasted decisions based on perceptual and conceptual features, while separately manipulating whether these decisions were driven by features in the environment or recovered from memory. Task-based fMRI identified regions that responded when stimulus independence and semantic retrieval were combined: these included left and right angular gyri and left middle temporal gyrus. Although these sites were within the default mode network, they showed a stronger response to demanding memory judgements than to an easier perceptual task, contrary to the view that they support automatic aspects of cognition. In a subsequent analysis, we showed that these regions were located at the extreme end of a macroscale gradient, which describes gradual transitions from sensorimotor to transmodal cortex. This shift in the focus of neural activity towards transmodal default mode regions might reflect isolation from specific sensory inputs, both when decisions are guided by conceptual as opposed to perceptual features and when cognitive states are generated in the absence of input.Highlights Brain regions supporting meaning overlap with stimulus independence.Bilateral angular gyri and left MTG respond strongly to both features of cognition.These patterns reflect a shift in activity towards regions of transmodal cortex.Complex memory representations may emerge in cortical areas distant from input. ER -