The dorsal and the default networks of the brain, which control externally directed and internally directed cognition, respectively, may work together more than previously believed.
Neuroscientists hypothesized the default network, responsible for tasks such as daydreaming, needed to be suppressed when the attention network was active, the region of the brain that controls decision making, in order to prevent interference.
But findings from a recent Journal of Neuroscience study suggest the two networks continuously interact to reconcile external goals with internal meaning.
The study involved a group of 36 adults who underwent functional neuroimaging while asked to differentiate famous from non-famous faces in a series of photographs. The participants were asked to identify and match faces that appeared earlier in the sequence -- tasks that involved both the attention and default networks.
Participants who had increased activation of the "reminiscing" default network on brain imaging also performed better on the goal-oriented cognitive portions of the task, the researchers found.
However, it remains unclear whether context affects the way the two brain networks work together, and if internally directed thought that is contextually irrelevant to the task at hand also improves externally focused cognition.
The human brain can concentrate on externally focused tasks, such as answering a question or solving a puzzle, or internally focused tasks, such as daydreaming. Until recently, these activities were believed to be mutually exclusive. That is, activating one suppressed the other. That is, activating one suppressed the other. But now, evidence suggests that engaging the internally focused brain network actually improves performance of the externally focused network.