Cognitive Mode Detectable with Task-Based fMRI: Default Mode B (DMB)

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 B (DMB), a task-negative and late-trial peaking cognitive mode. The BOLD signal configurations associated with DMB are modulated by a range of tasks, and here we present eight. For each task, we report: (1) specific pattern-based (as opposed to coordinate-based) anatomical details essential for distinguishing DMB from other BOLD-based cognitive modes, and (2) task-induced BOLD signal changes associated with DMB over a range of task conditions. In order to facilitate recognition, we nick-named the anatomical patterns specific to DMB as follows: (1) In Flight, (2) Medial Temporal Dots, (3) Snowman Nose, (4) Angel Wings, and (5) Tripod. Evidence for DMB was derived from the timing and magnitude of task-induced BOLD signal changes induced by the following tasks: working memory, spatial capacity, semantic association, evidence integration, Ravens matrices, autobiographical event simulation, meditation and social perception. It was observed that deactivations in DMB were sensitive to cognitive load during attention to specific features of the external environment, based on evidence from working memory, spatial capacity, semantic association, evidence integration, and Ravens matrices. It was also observed that activations in DMB involved a cognitive process for engaging in mental projection into self-relevant social narratives, based on evidence from autobiographical event simulation, meditation, and social perception. Future research may explore DMB activation over a wider range of tasks in larger samples.