Insulation for Daydreams: A Role for Tonic Norepinephrine in the Facilitation of Internally Guided Thought

People vary in how often they have thoughts unrelated to the task at hand, and this variation is linked to longer reaction times when a target appears while baseline pupil diameter is elevated. Because increased baseline pupil diameter can indicate higher tonic activity in the norepinephrine system, the findings suggest that high tonic norepinephrine activity may facilitate task-unrelated thoughts. The authors hypothesize that a high tonic mode of norepinephrine broadly reduces the amplification of task-relevant information, thereby prioritizing internally generated thoughts and shielding them from potentially disruptive external events.

Study at a glance

Abstract

Although consciousness can be brought to bear on both perceptual and internally generated information, little is known about how these different cognitive modes are coordinated. Here we show that between-participant variance in thoughts unrelated to the task being performed (known as task unrelated thought, TUT) is associated with longer response times (RT) when target presentation occurs during periods when baseline Pupil Diameter (PD) is increased. As behavioral interference due to high baseline PD can reflect increased tonic activity in the norepinephrine system (NE), these results might implicate high tonic NE activity in the facilitation of TUTs. Based on these findings, it is hypothesised that high tonic mode NE leads to a generalised de-amplification of task relevant information that prioritses internally generated thought and insulates it from the potentially disruptive events taking place in the external environment.