Cognitive Mode Detectable with Task-Based fMRI: Default Mode A (DMA)

In the context of task-based functional magnetic resonance imaging (fMRI), cognitive modes can be defined as task-general cognitive/sensory/motor processes which reliably elicit specific blood-oxygen-level-dependent (BOLD) signal pattern configurations. A number of cognitive modes are detectable with task-based fMRI, and here we focus on Default Mode A (DMA), a task-negative cognitive mode. The BOLD signal configurations associated with DMA are modulated by a range of tasks, and here we present four. For each task, we report: (1) specific pattern-based (as opposed to coordinate-based) anatomical details essential for distinguishing DMA from other BOLD-based cognitive modes, and (2) task-induced BOLD signal changes associated with DMA over a range of task conditions. In order to facilitate recognition, we nick-named the anatomical patterns specific to DMA as follows: (1) Snowman Mouth, (2) Muted Medial Temporal Dots, (3) Penguin, (4) Kitten, and (5) You’re in Trouble. Evidence for DMA was derived from the timing and magnitude of task-induced BOLD signal changes induced by phonological and semantic judgement tasks, lexical decision, and task switching. The DMA cognitive mode was inversely correlated with the language mode, and therefore showed greater deactivation when linguistic processing was required, but less deactivation when suppression of linguistic processes enhanced performance. We also provide an anatomical and functional comparison to Default Mode B (DMB).