“The Functional Architecture of Cognition Is Rhythmic”.  Indeed.

Randolph F. Helfrich, Robert T. Knight, Oscillatory Dynamics of Prefrontal Cognitive Control, In Trends in Cognitive Sciences, Volume 20, Issue 12, 2016, Pages 916-930, ISSN 1364-6613, https://doi.org/10.1016/j.tics.2016.09.007.

Ardid and Wang propose a model for task switching in which a weak rule signal provides a small bias that is dramatically amplified by reverberating dynamics in neural circuits. This leads to complete reconfiguration of sensory to motor mapping.  It seems to explain many observations in the extant literature.  Rules signals are often weak (but ubiquitous in frontal cortex), yet somehow manage to gain control over behavior

Peters et al used functional imaging in humans to examine the effects of the contents of working memory on extrastriate visual cortex.  Subjects performed a visual search task.  The target item in working memory enhanced processing of a matching visual input whereas other “accessory” items held in working memory suppressed extrastriate activity.  These dual effects may help focus on relevant tasks while avoiding distractions.